DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Applicant’s claim for the benefit of a prior-filed application under 35 U.S.C. 119(e) is acknowledged. The instant application, filed August 11, 2023, claims priority to U.S. Provisional Application No. 63/371,228, filed August 12, 2022.
Status of Claims
Pursuant to a Preliminary Amendment dated October 23, 2023, claims 1-5, 17, 24, 74, 77 and 80-87 are pending. Claims 6-16, 18-23, 26-73, 75, 76, 78, and 79 are cancelled, claims 1, 2, 74, and 77 remain in their original form, claims 3-5, 17, and 24 are amended, and claims 80-87 are new.
Information Disclosure Statement
The Information Disclosure Statements submitted on July 2, 2025, and October 23, 2023, are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statements have been considered by the examiner.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Background
The examiner believes that an extended background section aids the understanding of the following rejection because the subject matter of the instant disclosure involves action on two separate molecular mechanisms by two separate drugs in the specific context of liver cirrhosis with portal hypertension. These references are not directly incorporated into the body of the rejection unless explicitly referenced in the analysis of a specific claim.
The instant claims are generally directed to the treatment of liver cirrhosis in a subject using a combination of an endothelin receptor A antagonist in the form of zibotentan and a sodium-glucose cotransporter 2 inhibitor in the form of dapagliflozin.
Please note, that in the art, the endothelin receptor A is usually abbreviated as “ETA”, “ETAR”, or “ET-A”. Despite the use of different abbreviations for the endothelin receptor A by different authors, these abbreviations refer to the same receptor.
Sodium-glucose cotransporter 2 is typically abbreviated as “SGLT2”.
Background Review of Endothelin Receptor Antagonists in Cirrhosis (Örmeci 2022)
By way of background, reference is made to Necati Örmeci, “Endothelins and liver cirrhosis”, Port. Hypertens. Cirrhos., vol. 1, no. 1, pp. 66-72 (June 2022), hereinafter “Örmeci 2022”, which is attached hereto.
Örmeci 2022 reviews the treatment of cirrhosis in subjects using endothelin-1 (“ET-1”) receptor antagonists.
Örmeci 2022 explains that ET-1 belongs to a family of oligopeptides called endothelins, and that endothelins act through binding endothelin receptor A (“ETAR”) and endothelin receptor B (“ETBR”):
Endothelins are a family of 21-amino acid oligopeptides, called endothelin-1 (ET-1), endothelin-2 (ET-2), and endothelin 3 (ET-3), with two intramolecular disulfide bonds. Endothelins are mainly located in interlobular veins, interlobular artery endothelial cells, and hepatic stellate cells (HSCs). Endothelins bind to two G protein-coated endothelin receptors, called endothelin receptors A (ETAR) and B (ETBR).1,2
Örmeci 2022 at 66 (emphasis added).
Örmeci 2022 explains that ET-1 induces long-lasting vasoconstriction through binding endothelin receptor A and vasodilation through binding endothelin receptor B:
ET-1, which induces long-lasting vasoconstriction through ETAR and vasodilatation through ETBR, was first isolated from porcine aortic endothelial cells in 1988.13
Örmeci 2022 at 67 (emphasis added).
Örmeci 2022 explains that levels of ET-1 are elevated in patients with liver cirrhosis:
The levels of ET-1, ETAR, and ETBR in tissue have respectively been shown to be 7-, 5-, and 4.6-fold higher, respectively, in patients with liver cirrhosis than in controls.7,8
Örmeci 2022 at 67.
Örmeci 2022 explains that ET-1 has a greater affinity towards endothelin receptor A than other endothelins (viz. ET-2 and ET-3):
ET-1 acts by binding to endothelin A and/or B receptors, which are located on the membranes of endothelial cells and HSCs in the liver, and on other cell types, including vascular smooth muscle cells, Kupffer cells, polymorphonuclear cells, macrophages, and cells in the heart, brain, lungs, kidneys, and liver.14,15 Platelet activating factors (PAF) in Kupffer cells and on membranes are increased 2- and 1.48-fold, respectively, in cirrhotic rats treated with by CCL4. Kupffer cells are the main reservoir of PAFs.16 ET-1 has over 100-fold greater affinity for ETARs than ET-2 and ET-3, whereas all three endothelins have equal affinity for ETBRs.17
Örmeci 2022 at 67 (emphasis added).
Örmeci 2022 explains that in healthy subjects, ET-1 is metabolized and quickly cleared; however, in subjects with cirrhotic livers, ET-1 is overexpressed and slowly metabolized:
ETs are not stored in the organs. Approximately 20% of synthesized endothelins are secreted into the circulation. Endothelins are cleared quickly from the circulation by the lungs, liver, heart, and kidneys, with the lungs removing about 50% of the circulating ET-1 through ETBRs.18 Although ET-1 is normally metabolized by healthy livers, ET-1 metabolism is reduced, while ET-1 is overexpressed, in cirrhotic livers.19,20,21
Örmeci 2022 at 67.
Örmeci 2022 explains that ET-1 receptor antagonists are known to have serious side effects:
Dual ET antagonists were reported to have several side effects, such as liver toxicity, acute liver failure, accumulation of salt and water, testicular toxicity, headache, and teratogenicity.
Örmeci 2022 at 70.
Örmeci 2022 further reviews the use of ET-1 receptor antagonists in the context of liver disease. Generally, ET-1 receptor antagonists may be selective for antagonism of endothelin receptor A, endothelin receptor B, or nonselective, which is often referred to as “mixed”, i.e., the antagonist antagonizes both endothelin receptor A and endothelin receptor B.
The following provides excerpts from some of the studies that Örmeci 2022 reviews.
Selective endothelin receptor A antagonism:
Bile duct ligation was found to increase portal pressure and ET-1 concentrations in humans and in animal models. Treatment of rats with the ETAR antagonist, LU135252, at a dose of 80 mg/day for 1-6 weeks after bile duct ligation improved liver histology, reduced liver collagen by 60%, and reduced the levels of messenger RNA encoding hepatic procollagen alfa 1 and TIMP-1 (two major effectors of fibrosis) and serum procollagen type III.37 These results showed that ETAR antagonists can be used as anti-fibrotic drugs in chronic parenchymal diseases.37
Örmeci 2022 at 68 (emphasis added).
Two weeks after bile duct ligation or sham operation, hepatic hemodynamics were measured before and after intraportal administration of ETAR, ETBR, and mixed ET receptors. The ETAR antagonist, B123, reduced portal vein pressure in cirrhotic rats but did not in noncirrhotic rats.
Örmeci 2022 at 69 (emphasis added).
Acute blockage of ETAR with a selective ETAR receptor antagonist, ambrisentan, does not affect portal hemodynamics….1 ETAR antagonists reduce intra-portal vascular resistance by dilatation of the portal vein. This, in turn, reduces the contraction of HSCs, increases the diameter of sinusoids, facilitates the regression of liver fibrosis, and restores liver parenchyma, by clearing ET-1 from the circulation.29
Örmeci 2022 at 68 (emphasis added).
The above passage discussing the study of ambrisentan (reference 1), a selective, endothelin receptor A antagonist, references Hsu, Shao‐Jung, et al. "Endothelin receptor blockers reduce shunting and angiogenesis in cirrhotic rats", European Journal of Clinical Investigation, vol. 46, no. 6, pp. 572-580 (2016), hereinafter “Hsu 2016”, which is attached hereto and incorporated as background by reference.
Hsu 2016 discloses that:
In this study, both bosentan and ambrisentan, a mixed ETAR and ETBR antagonist and a selective ETAR antagonist, ameliorated the severity of portosystemic shunting in rats with BDL-induced liver cirrhosis. Furthermore, the antiangiogenic effects acted through the down-regulation of VEGF pathway and relevant angiogenic factors. The mechanism of this study is illustrated in Fig. S1.
Hsu 2016 at 575.
Fig. S1 of Hsu 2016 is reproduced below:
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Hsu 2016, Fig. S1 (available online in the journal’s Supporting Information section).
Furthermore, in the above passage, reference 29 is to Ling et al., “Comparison of endothelin receptors in normal versus cirrhotic human liver and in the liver from endothelial cell-specific ETB knockout mice”, Life Sciences, vol. 91, no. 13-14, pp. 716-722 (2012), hereinafter “Ling 2012”, which is also attached hereto and incorporated as background by reference.
Ling 2012 explains that the observed hepatoxicity of endothelin receptor antagonists may be caused by ETB antagonism:
Interestingly sinusoid diameter was reduced three fold in the knockout compared to wild type mice and intrahepatic branches of the portal vein were congested with red blood cells (Fig. 6). This suggests that blood was unable to pass through sinusoids effectively owing to reduced sinusoidal diameter and produced congestion in the portal venous system. Hence, sinusoidal endothelial cell ETB may be critical in maintaining adequate sinusoidal diameter. Therefore, ETB blockade which causes sinusoid constriction and consequent liver ischaemia may contribute to the liver toxicity observed with mixed antagonists. This suggests additional benefit of ETA selective compounds.
Ling 2012 at 7221 (emphasis added).
Selective endothelin receptor B antagonism:
Intraportal administration of ET-1 or sarafotoxin, an ET-B receptor agonist, at a dose of 0.5 nmol/kg increased portal pressure progressively in both cirrhotic and healthy control rats. Portal pressure was not reduced by administration of ETAR and ETBR antagonists alone, but was reduced in rats treated with both ETAR and ETBR antagonists. These results indicate that ET-1 plays a major role in portal hypertension accompanying liver cirrhosis.41
Örmeci 2022 at 68-69 (emphasis added).
Two weeks after bile duct ligation or sham operation, hepatic hemodynamics were measured before and after intraportal administration of ETAR, ETBR, and mixed ET receptors. … [T]he ETBR antagonist, BQ788, had no effect on cirrhotic rats but increased portal vein pressure in noncirrhotic rats.
Örmeci 2022 at 69 (emphasis added).
Mixed ETA and ETB antagonism
Both ET-1 and the ETBR agonist sarafotoxin increase HSC contractility, whereas bosentan, a mixed ET antagonist, decreases portal vein pressure in rats with portal hypertension.25
Örmeci 2022 at 67.
Intraperitoneal administration of 0.15 mg/kg CCl4 twice weekly for 8 weeks to rats induced liver cirrhosis, whereas intravenous administration of the ET-1 antagonist TAK-044 reduced portal pressure, improved hepatocellular necrosis about 35%, and reduced the concentrations of liver enzymes.38 Similarly, TAK-044 treatment of rats with CCl4-induced liver cirrhosis decreased ET-1 concentrations and ET receptor densities to normal levels.39 Although lipopolysaccharide (LPS) induces cirrhosis in rats, administration of LPS plus tezosentan, a mixed ET receptor antagonist, reduced liver enzyme and plasma TNF-alfa levels, along with hepatic myeloperoxidase activity and hepatic neutrophil levels, while increasing survival rates when compared with rats that received only LPS.40
Örmeci 2022 at 68.
Oral administration of bosentan results in a rapid decrease in pulmonary arterial pressure and an increase in cardiac index.18 Bosantan treatment of a patient with portopulmonary hypertension due to cryptogenic cirrhosis for 16 and 31 weeks reduced pulmonary artery pressure from 88 mmHg to 43 and 58 mmHg, respectively, and reduced hepatic portal vein pressure gradient from 26 mmHg to 7 and 17 mmHg, respectively.54 Similarly, bosentan treatment of a patient with portopulmonary hypertension due to alcoholic cirrhosis for 9 months reduced pulmonary vascular resistance 60% and mean pulmonary artery pressure from 55 to 44 mmHg. Moreover, bosentan was well tolerated.55
Örmeci 2022 at 69-70.
Background Review of SGLT2 Inhibitors in Liver Patients (Hsiang 2020)
By way of background, reference is made to Hsiang, John Chen, and Vincent Wai-Sun Wong. "SGLT2 inhibitors in liver patients." Clinical Gastroenterology and Hepatology, vol. 18, no. 10, pp. 2168-2172 (2020), hereinafter “Hsiang 2020”, which is attached hereto.
Hsiang 2020 reviews the use of SGLT2 inhibitors in liver patients. As background, Hsiang 2020 discloses that:
SGLT2 inhibitors are relevant to gastroenterologists and hepatologists for 2 main reasons. First, because of their multiple metabolic benefits, SGLT2 inhibitors may be useful in patients with nonalcoholic fatty liver disease (NAFLD) (or recently proposed to be renamed as metabolic associated fatty liver disease). Second, type 2 diabetes is a major risk factor of cirrhosis and hepatocellular carcinoma. Some patients with clinical indications for SGLT2 inhibitors would have underlying cirrhosis and even hepatic decompensation. In this article, we summarize current knowledge about the effect of SGLT2 inhibitors on NAFLD, side effects of this class of drug, and their safety in patients with cirrhosis.
Hsiang 2020 at 2168.
Hsiang 2020 reports the effect of SGLT2 inhibitors on liver fat in Table 1:
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Hsiang 2020 at 2169.
Background Review of Zibotentan
As the Specification explains, zibotentan, or ZD4054, was disclosed in a patent application that published in 1996 and “is a selective endothelin (ETA) receptor antagonist with a high level of selectivity over ETB (ETA IC50=13 nM, no effect at the ETB up to 50 mM)”. Specification at page 11, paragraph [0055] (citing Morris et al., Br J Cancer 2005, 92(12):2148-2152). The chemical structure of zibotentan is provided below.
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Specification at page 11, paragraph [0055].
Single oral dose of 10 mg zibotentan is known to be safe to administer to patients with hepatic impairment. See, for example, Helen Tomkinson et al., “Pharmacokinetics and tolerability of zibotentan (ZD4054) in subjects with hepatic or renal impairment: two open-label comparative studies”, BMC Clinical Pharmacology, vol. 11, no. 3, pp. 1-11 (2011), hereinafter “Tomkinson 2011”, at page 10 of 11:
Following administration of a single oral dose of ziboten-tan 10 mg to subjects with hepatic or renal impairment, the Cmax of zibotentan was unchanged, although ziboten-tan exposure (AUC) was higher in subjects with hepatic or renal impairment as a consequence of slower clearance of zibotentan. The magnitude of the increase in exposure was related to the degree of hepatic or renal impairment. Despite this increased exposure, there were no differences in the type or severity of AEs. Zibotentan 10 mg is cur-rently undergoing further clinical investigation in patients with CRPC in a large Phase III clinical programme [11].
Tomkinson 2011 at page 10 of 11.
Background Review of Dapagliflozin
The Specification explains that dapagliflozin “is a potent, selective, and orally active inhibitor of sodium-glucose cotransporter 2 (SGLT2)….” Specification at pages 11-12, paragraph [0056]. The chemical structure of dapagliflozin is provided below.
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Specification at pages 11-12, paragraph [0056].
AstraZeneca AB markets 5 mg and 10 mg dapagliflozin tablets under the name FARXIGA® (FARXIGA® received FDA approval in 2014). See FARXIGA® Label, revised 04/2021, pages 1-52, hereinafter the “04/2021 FARXIGA® Label”, at 1. As seen in the 04/2021 FARXIGA® Label, FDA approved FARXIGA® for the following new indications:
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04/2021 FARXIGA® Label at 2.
FARXIGA® is known to be safe to administer to patients with hepatic impairment.
No dose adjustment is recommended for patients with mild, moderate, or severe hepatic impairment. However, the benefit-risk for the use of dapagliflozin in patients with severe hepatic impairment should be individually assessed since the safety and efficacy of dapagliflozin have not been specifically studied in this population [see Clinical Pharmacology (12.3)].
04/2021 FARXIGA® Label at 15.
Claims 1 - 5 were obvious over Zipprich 2020 in view of WO’251, Montalvo-Gordon 2020, and Smeijer 2021
Claims 1-5 are rejected under 35 U.S.C. 103 as being unpatentable over Zipprich, Alexander, et al., "Effect of ET‐A blockade on portal pressure and hepatic arterial perfusion in patients with cirrhosis: A proof of concept study." Liver International, vol. 41, no. 3, pp. 554-561 (2021), hereinafter “Zipprich 2020”, in view of Navarro, Iker, “Treatment of Portal Hypertension and Cirrhosis”, International Publication No. Wo 2020/094251 A2, published on May 14, 2020, hereinafter “WO’251”, Montalvo‐Gordon, Iaarah, et al., "Sodium‐glucose cotransporter 2 inhibitors ameliorate ascites and peripheral edema in patients with cirrhosis and diabetes", Hepatology, vol. 72, no. 5, pp. 1880-1882 (2020), hereinafter “Montalvo‐Gordon 2020”, and Smeijer, David J. et al., “Endothelin receptor antagonists for the treatment of diabetic and nondiabetic chronic kidney disease”, Current Opinion in Nephrology and Hypertension, vol. 30, no. 4, pp. 456-465 (July 2021), hereinafter “Smeijer 2021”.
Claim 1 is generally directed to a method of treating liver cirrhosis using combination of an endothelin receptor A antagonist and a sodium-glucose cotransporter 2 inhibitor.
In particular, applicants allege a drug combination of zibotentan, a known endothelin receptor A antagonist, and dapagliflozin, a known sodium-glucose cotransporter 2 (“SGLT2”) inhibitor SGLT2 inhibitor. Applicants purport that the combination may be used to treat cirrhosis patients with features of portal hypertension and propose certain studies of the efficacy, safety, and tolerability of the combination therapy. Applicants do NOT report any clinical data or experimental results from the combination.
Zipprich 2020
Zipprich 2020 discloses the use of endothelin receptor A (“ET-A”) antagonists to treat patients with cirrhosis and portal hypertension, wherein the “[a]dministration of a selective ET-A antagonist decreases the portal pressure in cirrhotic patients.” Zipprich at Abstract.
In particular, Zipprich 2020 reports the study of endothelin receptor A antagonists BQ-123 and ambrisentan in patients with cirrhosis:
Two different substudies were performed: the first substudy was performed to evaluate the local effects of endothelin-A receptor blockade (BQ-123) administered to the hepatic artery. This via of administration was chosen in order to try to minimize the systemic effects of the drug. The second substudy evaluated the systemic oral administration of Ambrisentan, a selective ET-A inhibitor….
Zipprich 2020 at 555 (emphases added).
Excerpts from Zipprich 2020 regarding the two substudies referenced in the above passage are provided below:
Local Administration of Endothelin Receptor A Antagonist BQ-123 Infused into the Hepatic Artery
In this study, different doses of a selective ET A Blocker (BQ 123) were infused into the hepatic artery. HVPG decreased from 17 mm Hg [IQR: 11-20] to 14 mm Hg [IQR: 9-19; P = .05] as a result of the administration of BQ 123 (Table 2; Figure 2A). This corresponds to a relative decrease of −12.5% (IQR: −40 to 0). The haemodynamic effects were greater and clinically relevant in Child-Pugh B −30% (IQR: −43.8 to −11.8) but not in Child-Pugh C patients −6.2% (IQR: −17.4 to 4.2; Figure 3B). No differences in the baseline HVPG was seen among those who had a clinically relevant reduction of HVPG.
Zipprich 2020 at 557 (emphasis added).
Table 2 referenced in the above passage is reproduced below:
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Zipprich 2020 at 557, Table 2.
Oral Systemic Administration of Endothelin Receptor A Antagonist Ambrisentan
The effects of the oral administration of the selective endothelin-A blocker on hepatic haemodynamics (hepatic vein catheterization), pulmonary and systemic haemodynamics as measured by right heart catheterization and on the hepatic arterial haemodynamics, as measured by percutaneous ultrasound are shown on Table 3. While there was a slight but significant decrease in mean arterial pressure (−2.0 mm Hg [IQR: −7.3 to 0.0]; P = .002), there were no changes in CO, CI, and SVR. Central venous pressure did not change because of the administration of Ambrisentan (P = .13). The decrease in mean pulmonary arterial pressure (mPAP) under Ambrisentan was borderline significant (P = .054), whereas the wedge pulmonary pressure had no significant change (P = .24; Table 3). There were no changes in the pulsatility (P = .38) and resistance index (P = .93) of the hepatic artery during the administration of Ambrisentan (Table 3).
Zipprich 2020 at 558-59 (emphasis added).
Table 3 referenced in the above passage is reproduced below:
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Zipprich 2020 at 559, Table 3.
The selective endothelin-A blocker led to a significant reduction of HVPG in all patients (−5.0% [IQR: −11.5% to 0.0%], P = .01; Figure 2B). There were no differences between the two different doses (Figure 3D). Five patients showed a clinically relevant reduction (ie reduction of 10%) of HVPG. Two patients had a decrease of HVPG but less than 10%. Five patients had no change of HVPG and one patient had an increase (Figure 2B). The relative changes of HVPG are shown in Figure 3C with a significant reduction in Child-Pugh A and B. There were no differences in the magnitude of the reduction of HVPG between patients with Child-Pugh A and B cirrhosis compared to Child-Pugh class C patients (P = .61) most likely towing to the small number of patients. There was no correlation between the relative changes of HVPG and Doppler-derived relative changes of portal vein flow (r = 0.37; P = .29). Additionally, there was no correlation between relative changes of HVPG and relative changes of mean blood pressure (r = 0.18; P = .5) and relative changes of pulsatility index of the hepatic artery (r = −0.22; P = .43). Furthermore, there was no correlation between relative changes of the systemic blood pressure and relative changes of the changes in hepatic arterial PI (r = −0.04; P = .88). In summary, no correlation between relative changes of systemic blood pressure or hepatic arterial Doppler flow parameters and changes in portal pressure could be observed, suggesting that the effect of oral administration of endothelin-A blocker on portal pressure was due its local effect independent from changes in systemic haemodynamics.
Zipprich 2020 at 559 (emphasis added).
Comparison to Administration of Mixed Endothelin Receptor Agonists and Prior Studies
This result contrasts with the previous study evaluating endothelin blockade in portal hypertension, in which no effect on HVPG was observed.16-18 The main difference between the studies is that the previous studies used a systemic administration of BQ123,18 so that the exact dose reaching the liver was unclear or an oral non-selective endothelin blocker which blocked both ET-A and ET-B receptors such as Tezosentan or Macitentan.16, 17 In the present study, a selective ET-A blocker was administered locally and systemically.
Endothelin-1 is one of the key molecules for vasoconstriction in the intrahepatic vascular bed. Several animal and human studies have shown an increased concentration of endothelin-1 in cirrhosis in hepatic tissue and serum.23-27 Endothelin-1 binds to both receptors, the endothelin-A and endothelin-B receptor,12 the former with vasoconstrictive properties while the latter has mainly vasodilatory properties. These receptors are found on hepatic stellate cells (endothelin-A receptor) and sinusoidal endothelial cells (Endothelin-B receptor).28 The hepatic stellate cells are the main cell type responsible for intrahepatic vasoconstriction and are located in the Space of Disse.28 Once endothelin-1 binds to the ET-A receptor on the hepatic stellate cell, this leads to an increase of inositol triphosphate, diacylglycerol and protein kinase C which in turn leads to vasoconstriction.28, 29 On the other hand, the endothelin-B receptor is located on the sinusoidal endothelial cells and mediates vasodilatation.28 Therefore, it is logical that inhibition of both receptors leads to a mitigation or lack of effect on HVPG, while use of a selective endothelin-A receptor blocker has a greater effect on HVPG. Indeed, our results indicate a major role of the endothelin-A receptor in the increased intrahepatic resistance in cirrhosis.
Zipprich 2020 at 559 (emphases added).
Zipprich 2020 further teaches that:
In conclusion, local and systemic administration of a selective endothelin-A blocker leads to a decrease in portal pressure, which was dose independent.
Zipprich 2020 at 560 (emphasis added).1,2
While Zipprich 2020 teaches that local and systemic administration of a selective endothelin receptor A antagonist leads to a decrease in portal pressure in patients with cirrhosis, it does not explicitly teach: 1) the specific selection of the endothelin receptor A antagonist zibotentan; 2) the addition of dapagliflozin, an SGLT2 inhibitor.
However, one of ordinary skill in the art at the time of filing would have a reasonable expectation of success in selecting zibotentan and dapagliflozin because:
WO’251 discloses the use of zibotentan in the treatment of portal hypertension associated with cirrhosis;
Montalvo‐Gordon 2020 discloses the use of SGLT2 inhibitors in the treatment of ascites and peripheral edema in patients with cirrhosis;
the combination of zibotentan and dapagliflozin have a proven safety profile when used together (Smeijer 2021).
WO’251
WO’251 generally discloses the treatment of portal hypertension associated with cirrhosis using endothelin receptor A (“ETA”) antagonists:
This invention relates to the treatment and prevention of Portal Hypertension and its complications, in particular to Portal Hypertension associated with cirrhosis and to related therapeutic and prophylactic formulations.
WO’251 at 1.
WO’251 generally reviews the use of endothelin receptor antagonists in the treatment of cirrhosis, including citation to Zipprich 2020 discussed above. See WO’251 at 1-6 (citation to Zipprich 2020 appears on page 5).
WO’251 teaches that:
The inventors have found that portal hypertension, in particular portal hypertension associated with cirrhosis, can be prevented and treated by administering selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).
WO’251 at 6 (emphasis added).
WO’251 teaches many embodiments for the treatment of portal hypertension, cirrhosis progression and the complications cirrhosis that include the use of ambrisentan,3 see, e.g., WO’251 at 16-23.4
WO’251 discloses that zibotentan may be used instead of ambrisentan:
The above embodiments also apply to zibotentan and atrasentan, and their individual embodiments are also included.
WO’251 at 23 (emphases added).
WO’251 further discloses that treatment with endothelin receptor agonists may induce fluid retention, particularly when endothelin receptor B is significantly antagonized:
"Does not significantly antagonize endothelin receptor type B" means that the administered compound does not antagonize ETB at all or to such an extent that the vasodilatory effect of the ETA antagonism is not compromised or adverse renal effects, such as fluid retention and which are secondary to an antagonism of the ETB receptor, are not observed in a patient. When the ETB is significantly antagonized, the reduction in portal pressure caused by antagonizing ETA is reduced, not observed or even counteracted completely.… When [endothelin receptor type B is] significantly antagonized in a patient, the incidence and severity of adverse renal effects such as weight gain, retention of fluid, formation of ascites, and/or pulmonary edema are increased.
WO’251 at 10-11 (emphases added, citation modified in brackets for clarity).
Montalvo‐Gordon 2020
Montalvo‐Gordon 2020 discloses results from the administration of SGLT2 inhibitors in patients with cirrhosis and diabetes. As background, Montalvo‐Gordon 2020 explains that while SGLT2 inhibitors, such as dapagliflozin, are indicated for patients with type 2 diabetes (“T2D”), 1) patients with cirrhosis commonly have T2D, 2) that SGLT2 inhibitors are safe and well-tolerated in patents with cirrhosis, and 3) that SGLT2 inhibitors exert a benefit with respect to ascites (a type of fluid retention cirrhotic patients may develop):
Sodium-glucose cotransporter 2 inhibitors (SGLT2-I; empagliflozin, canagliflozin, and dapagliflozin) are the most recently approved drugs for type 2 diabetes (T2D).(1)
T2D is common in patients with cirrhosis, particularly in those with nonalcoholic steatohepatitis (NASH). SGLT2-I appear to be safe and well-tolerated in patients with cirrhosis,(2) and because, besides promoting urinary glucose excretion, they also promote sodium excretion, they could have an additional benefit in those with ascites.(3)
We describe the course of fluid retention in 3 patients with NASH cirrhosis and T2D who received SGLT2-I.
Montalvo‐Gordon 2020 at 1880 (emphasis added).
Regarding fluid retention in cirrhotic patients (e.g., ascites), Montalvo‐Gordon 2020 explains that ascites is a critical complication of cirrhosis, and that ascites is often treated with diuretics:
Ascites is the most frequent complication of cirrhosis and is the one with the poorest survival rate. Treatment of ascites is based on achieving a negative sodium balance by increasing sodium excretion (diuretics) and by decreasing dietary sodium intake. Patients on diuretics may develop complications such as encephalopathy, hyponatremia, or AKI that require dose reduction or discontinuation, resulting in inadequate control of ascites/edema. In these cases, management options for ascites consist of serial large-volume paracenteses or transjugular intrahepatic portosystemic shunts, treatments not free of complications.
Montalvo‐Gordon 2020 at 1881 (emphases added).
Montalvo‐Gordon 2020 reports three patients with nonalcoholic steatohepatitis (“NASH”) cirrhosis and T2D who were free of ascites and edema following treatment with SGLT2 inhibitors. See Montalvo‐Gordon 2020 at 1880-1881 (Patient 1 free of ascites and edema after 10 mg and 25 mg q.d. empagliflozin, later spironolactone added to treat mild peripheral edema; Patient 2 on insulin and propranolol free of ascites and edema after 100 mg q.d. canagliflozin; Patient 3 free of ascites and edema after 150/1,000 mg b.i.d. canagliflozin/metformin).
Montalvo‐Gordon 2020 reports that administration of SGLT2 inhibitors to the cirrhotic patients did not cause abnormalities in patients’ laboratory values:
Changes in liver enzymes, bilirubin, and INR (International Normalized Ratio) were not observed in any of the 3 cases (Table 1). Urinary sodium levels were not obtained. A urinary tract infection was not observed in any case.
Montalvo‐Gordon 2020 at 1881.
Montalvo‐Gordon 2020 explains 1) that SGLT2 inhibitors exert a diuretic effect through a different mechanism than the mainstay diuretic therapy in cirrhosis, and that 2) the results support the investigation of SGLT2 inhibitors in clinical trials for patients with cirrhotic ascites/edema without diabetes:
SGLT2-I induce natriuresis by inhibiting proximal tubular reabsorption of both glucose and Na+ (for every molecule of glucose that is not absorbed, the transport of one Na+ ion is inhibited).(1) This is a different mechanism from that of spironolactone (the mainstay of diuretic therapy in cirrhosis), which acts by blocking the aldosterone-dependent Na-K exchange site in distal tubules. NASH is a rising cause of cirrhosis worldwide and is frequently associated with T2D. Although these drugs have been shown to be safe in patients with NASH cirrhosis,(2, 3) their usefulness in the management of cirrhotic ascites and edema has not been examined. We have described three cases of patients with cirrhosis, T2D mellitus, and fluid retention with normal baseline creatinine, in whom the use of SGLT2-I had a beneficial effect on fluid retention, with improvement in serum sodium, without development of AKI or encephalopathy, and without evidence of hepatotoxicity. These findings support the performance of clinical trials exploring the inclusion of SGLT2-I in the therapeutic algorithm of cirrhotic ascites/edema, even in those without T2D. Close monitoring of patients on these drugs is necessary, as they may lead to hypotension/volume depletion (particularly in those also on diuretics) and have been associated with urinary tract infections.(4)
Montalvo‐Gordon 2020 at 1881-1882 (emphasis added).
Smeijer 2021
Smeijer 2021 generally discloses clinical findings of endothelin receptor antagonists (“ERAs”) in various etiologies of kidney disease (e.g., diabetic chronic kidney disease). Smeijer 2021 discloses that ERAs, even those that specifically target the endothelin receptor A, are known for their fluid retaining effects:
Despite use of low doses of ERA with high selectivity for the ETA receptor, their fluid retaining effects and associated risks of edema and heart failure remain present. Diuretic treatment in combination with ERA may mitigate fluid retention as previously shown. Sodium glucose cotransporter-2 (SGLT2) inhibitors were originally developed as glucose-lowering drugs and have been shown to exert diuretic effects. In addition, SGLT2 inhibitors reduce albuminuria and reduce the risks of kidney failure, heart failure, and mortality in patients with CKD with and without type 2 diabetes [52]. Because SGLT2 inhibitors exert diuretic effects, whereas ERA heighten the risk of sodium and fluid retention, the diuretic properties of an SGLT2i could attenuate the fluid retaining effects of an ERA, whereas the antialbuminuric effects may be complimentary owing to the different mechanisms of action of the two drug classes.
Smeijer 2021 at 462-463 (emphases added).
Smeijer 2021 further discloses 1) that studies have been designed to combine ERAs with SGLT2 inhibitors in order to take advantage of the diuretic effects that SGLT2 inhibitors exert, and 2) the specific combination of zibotentan and dapagliflozin:
Interestingly, a recent posthoc analysis of the SONAR trial reported that combination treatment with SGLT2 and atrasentan indeed enhanced albuminuria reduction, whereas the fluid retaining effects of atrasentan were mitigated when atrasentan was co-administered with an SGLT2 inhibitor (Fig. 5) [53▪]. As this analysis concerned a retrospective analysis of small number of patients, prospective clinical trials are needed. The ongoing phase 2 ZENITH trial (NCT04724837) will examine whether fluid retention with the ERA zibotentan can be mitigated by the SGLT2 inhibitor dapagliflozin in patients with type 2 diabetes and CKD.
Smeijer 2021 at 463 (emphasis added).5
Claim 1 was Obvious at the Time of Filing
First, one having ordinary skill in the art at the time of filing would be motivated to treat liver cirrhosis in a subject in need thereof using an endothelin receptor A antagonist because Zipprich 2020 discloses that administration of a selective endothelin receptor A antagonist, such as ambrisentan, decreases the portal pressure in cirrhotic patients. Zipprich 2020 at Abstract. One having ordinary skill in the art at the time of filing would have a reasonable expectation of success in selecting zibotentan as the endothelin receptor A antagonist because WO’251 discloses that “portal hypertension, in particular portal hypertension associated with cirrhosis, can be prevented and treated by administering selective ETA antagonists [ambrisentan, zibotentan, or atrasentan] in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).” WO’251 at 6 (citation modified in brackets, support appears in WO’251 at 23, discussed above).
Second, one having ordinary skill in the art at the time of filing would be motivated to treat liver cirrhosis in a subject in need thereof using an SGLT2 inhibitor because Montalvo-Gordon 2020 discloses that “[a]scites is the most frequent complication of cirrhosis and is the one with the poorest survival rate”, id. at 1881, and that in “three cases of patients with cirrhosis, T2D mellitus, and fluid retention with normal baseline creatinine, … the use of SGLT2-I had a beneficial effect on fluid retention, with improvement in serum sodium, without development of AKI or encephalopathy, and without evidence of hepatotoxicity. These findings support the performance of clinical trials exploring the inclusion of SGLT2-I in the therapeutic algorithm of cirrhotic ascites/edema, even in those without T2D.” id. at 1881. One of ordinary skill in the art would have a reasonable expectation of success in selecting dapagliflozin as the SGLT2 inhibitor because Montalvo-Gordon 2020 discloses dapagliflozin is an approved SGLT2 inhibitor, as well as empagliflozin and canagliflozin.
Third, one having ordinary skill in the art at the time of filing seeking to design a method to treat cirrhosis using an endothelin receptor A antagonist would be drawn to the literature surrounding administration of endothelin receptor A antagonist in patients with diabetes because “T2D is common in patients with cirrhosis”. Montalvo-Gordon 2020 at 1880. Therefore, one of ordinary skill in the art at the time of filing would be aware of the teachings of Smeijer 2021 that disclose “[d]espite use of low doses of ERA with high selectivity for the ETA receptor, their fluid retaining effects and associated risks of edema and heart failure remain present.” Smeijer 2021 at 462. One having ordinary skill in the art at the time of filing would be motivated to combine zibotentan and dapagliflozin because Smeijer 2021 discloses the combination has a proven safety profile as evidenced through “[t]he ongoing phase 2 ZENITH trial (NCT04724837) [that] will examine whether fluid retention with the ERA zibotentan can be mitigated by the SGLT2 inhibitor dapagliflozin in patients with type 2 diabetes and CKD.” Smeijer 2021 at 463 (citation modified in brackets).
Therefore, one having ordinary skill in the art at the time of filing would have a reasonable expectation of success in designing a method of treating liver cirrhosis in a subject by administering a combination of zibotentan and dapagliflozin because 1) both zibotentan and dapagliflozin belong to limited classes of drugs known to be individually therapeutically effective in the treatment of cirrhosis, as explained above by WO’251 and Montalvo-Gordon 2020, respectively, 2) the benefit of the combination of zibotentan and dapagliflozin whereby dapagliflozin would reduce fluid retention caused by zibotentan was known (Smeijer 2021), and 3) their combination was safe to administer to patients with type 2 diabetes and chronic kidney disease (Smeijer 2021).
Therefore, claim 1 was obvious at the time of filing.
Claim 2 was Obvious at the Time of Filing
Regarding claim 2, it recites the method of claim 1, wherein the subject has “features of portal hypertension”. Because the Specification does not offer a special definition of the term “features of portal hypertension”, the term is afforded its plain and ordinary meaning consistent with the specification, which is at least two signs or symptoms associated with portal hypertension such as ascites, edema, elevated HVPG, or simply a clinical finding of portal hypertension.
Zipprich 2020, WO’251, Montalvo-Gordon 2020, and Smeijer 2021 are relied upon as above.
Zipprich 2020 discloses treatment of patients “with cirrhosis who underwent TIPS evaluation without any exclusion criteria”, id. at 555, and provides baseline characteristics of the patients in Tables 1-3 that indicate portal hypertension, id. at 557 and 559 (Tables 2 and 3 are reproduced above in the section pertaining to claim 1).
WO’251 discloses its “invention relates to the treatment and prevention of Portal Hypertension and its complications, in particular to Portal Hypertension associated with cirrhosis”. WO’251 at 1 (emphasis added).
Montalvo‐Gordon 2020 discloses the treatment of cirrhotic patients with both ascites and edema. See Montalvo-Gordon 2020 at 1180-1881, discussed above.
One having ordinary skill in the art at the time of filing would have a reasonable expectation of success in designing a method of claim 1, wherein the subject has features of portal hypertension, because Zipprich 2020, WO’251, and Montalvo-Gordon 2020 each apply to patients with features of portal hypertension.
Therefore, claim 2 was obvious at the time of filing over the references for the reasons given above, and for the same reasons that claim 1 was obvious over the references at the time of filing.
Claims 3 - 5 were Obvious at the Time of Filing
Claims 3, 4, and 5 recite the method of claim 1, wherein the subject has a hepatic venous pressure gradient (“HVPG”) greater than 5, 7.5, and 10 mmHg, respectively.
The Specification at page 14, paragraph [0064], defines portal hypertension based on an HVPG of > 5 mmHg. See Specification at page 14, paragraph [0064] (“An HVPG of > 5 mmHg defines portal hypertension, and if the measurement exceeds 10 mmHg it is called clinically significant portal hypertension. At levels above 12 mm Hg, the risk for variceal haemorrhage may further increase.”).
Zipprich 2020, WO’251, Montalvo-Gordon 2020, and Smeijer 2021 are relied upon as above.
Zipprich 2020 discloses patient baseline HVPG measurements of 11.0 – 25.0 mmHg. See Zipprich 2020 at 557, Table 1.
WO’251 discloses in one example that “[a]ll subjects had portal hypertension as determined by HVPG at baseline (mean 19.7 mmHg, range 9-29 mmHg).” WO’251 at 41.
Montalvo-Gordon 2020 discloses the treatment of patients with both ascites and edema, which indicates that the patients had portal hypertension. See Montalvo-Gordon 2020 at 1180-1881, discussed above.
One having ordinary skill in the art at the time of filing would have a reasonable expectation of success in designing a method of claim 1, wherein the subject has an HVPG above 5, 7.5, or 10.0 mmHg, because 1) Zipprich 2020, WO’251, and Montalvo-Gordon 2020 each apply to patients with portal hypertension, and 2) Zipprich 2020 and WO’251 expressly teach reduction in portal hypertension in cirrhotic patients with HVPG above 10 mmHg.
Therefore, claims 3-5 were obvious at the time of filing over the references for the reasons given above, and for the same reasons that claim 1 was obvious over the references at the time of filing.
Claim 17 was obvious over Zipprich 2020 in view of WO’251, Montalvo-Gordon 2020, Smeijer 2021, Tomkinson 2011, Clarkson-Jones 2011, 2003 FDA Guidance, and 2005 FDA Guidance
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Zipprich 2020, in view of WO’251, Montalvo‐Gordon 2020, Smeijer 2021, Helen Tomkinson et al., “Pharmacokinetics and tolerability of zibotentan (ZD4054) in subjects with hepatic or renal impairment: two open-label comparative studies”, BMC Clinical Pharmacology, vol. 11, no. 3, pp. 1-11 (2011), hereinafter “Tomkinson 2011”, Clarkson-Jones et al., “The disposition and metabolism of zibotentan (ZD4054): an oral-specific endothelin A receptor antagonist in mice, rats and dogs”, Xenobiotica, vol. 41, no. 9, pp. 784-796 (2011), hereinafter “Clarkson-Jones 2011”, U.S. Department of Health and Human Services, Food and Drug Administration, Center for Drug Evaluation and Research (CDER), “Guidance for Industry: Pharmacokinetics in Patients with Impaired Hepatic Function: Function: Study Design, Data Analysis, and Impact on Dosing and Labeling”, May 2003, hereinafter the “2003 FDA Guidance”, and U.S. Department of Health and Human Services, Food and Drug Administration, Center for Drug Evaluation and Research (CDER), “Guidance for Industry: Estimating the Maximum Safe Starting Dose in Initial Clinical Trials for Therapeutics in Adult Healthy Volunteers”, July 2005, hereinafter the “2005 FDA Guidance”.
Zipprich 2020, WO’251, Montalvo-Gordon 2020, and Smeijer 2021 are relied upon as above.
Claim 17 recites the method of claim 1, wherein the composition comprises about 0.5 mg to about 20 mg zibotentan.
The Specification states that the term “about” is used to indicate that a value includes inherent variation of error, which may be approximately up “20% or higher variability” of the recited value that “about” modifies. Specification at page 9, paragraph [0047].
Zipprich 2020, WO’251, Montalvo-Gordon 2020, and Smeijer 2021 do not explicitly teach a dose of about 0.5 mg to about 20 mg zibotentan.
However, one of ordinary skill in the art at the time of filing would have a reasonable expectation of success in selecting a range of about 0.5 mg to about 20 mg zibotentan for use in the method of claim 1 because:
the range of 5 mg – 22.5 mg zibotentan was known in the art (Tomkinson 2011),
WO’251 suggests a lower starting dose of endothelin receptor antagonists for the treatment of subjects with portal hypertension, and
safety concerns regarding the administration of zibotentan to patients with hepatic impairment indicate a lower starting dose (Clarkson-Jones 2011, 2003 FDA Guidance and 2005 FDA Guidance).
Tomkinson 2011
Tomkinson 2011 discloses that 10 mg zibotentan was safe for single oral dose administration to subjects with hepatic impairment. See Tomkinson 2011 at Conclusion, page 10 of 11. Compared to control subjects, the Cmax of zibotentan was unchanged, while AUC was higher due to reduced clearance. Id. However, “there were no differences in the severity of [adverse events]” compared to the control group. Id.
Tomkinson 2011 cites to other studies of zibotentan in patients with other conditions, wherein patients received zibotentan at doses of:
between 5 mg and 15 mg zibotentan, exhibiting dose-linear increase (id. at page 2 of 11, citing Ranson et al., “Pharmacokinetic and tolerability profile of once-daily zibotentan (ZD4054) in Japanese and Caucasian patients with hormone-resistant prostate cancer”, Int J Clin Pharm Ther 2010, 48:708-717),
22.5 mg zibotentan, exhibiting adverse events (id. at page 10 of 11, citing Schelman et al., “A phase I study of zibotentan (ZD4054) in patients with metastatic, castrate-resistant prostate cancer”, Invest New Drugs 2009, 29:118-125).
WO’251
WO’251 discloses that approved dosages of endothelin receptor antagonists for treating pulmonary arterial hypertension may lead to plasma levels of the agonist that significantly antagonizes the effects of endothelin on the endothelin receptor B in subjects with portal hypertension, which may offset the benefit of antagonizing the endothelin receptor A in subjects with portal hypertension:
Contrary to the methods and formulations of the present invention, the approved dosage and formulations of endothelin receptor antagonists for the treatment of PAH create plasma levels of the endothelin receptor antagonist that significantly antagonize the effects of endothelin on the ETB receptors as well as the effects of endothelin on the ETA receptors in subjects with portal hypertension thereby causing no effect or increased rather than decreased portal pressure. For example, ambrisentan, sold under the product name of Letairis® in the US and Volibris® in Europe, was approved for daily oral administration at a dosage strength of 5 mg and 10 mg. Plasma levels following one-time administration of Letairis® in patients without liver impairment often reach 700 ng/ml, and generally are found in the range of about 350 ng/ml or 670 ng/ml for the 5 mg and 10 mg doses, respectively. In patients with liver impairment, concentrations of ambrisentan are higher. Such concentrations are too high to be effective in treating portal hypertension and in fact are counterproductive because they contribute to the loss of intra-hepatic vasodilation and hence may increase the pressure in the portal venous system and induce fluid retention by the kidney.
WO’251 at 14-15
WO’251 further discloses that in subjects with portal hypertension associated with cirrhosis, the comorbidities of liver dysfunction and possible renal impairment may cause higher drug accumulation that may lead to the blockade of the endothelin receptor B, which may induce fluid retention:
In addition, subjects, who develop portal hypertension, in particular portal hypertension associated with cirrhosis, generally suffer from significant liver dysfunction and occasionally renal impairment. Because of these comorbidities, this patient population cannot metabolize administered medications effectively, resulting in a higher accumulation of the drug compared to subjects without liver and/or renal impairment. Thus, the blood level of ambrisentan, when administered daily for oral administration as approved for PAH, will achieve concentrations that are too high and steadily increase over a few days to a trough (i.e. pre-dose) concentration in blood that is well above the desired and effective concentration used in the present invention. These high concentrations may lead to the blockade of ETB receptor sites, which in turn leads to loss of intra-hepatic vasodilation and hence may aggravate the pressure in the portal venous system and induce fluid retention by the kidney.
WO’251 at 15.
WO’251 further discloses other factors leading to a recommendation that the starting dose for endothelin receptor agonists in the treatment of portal hypertension associated with cirrhosis. See, e.g., WO’251 at 15-16 (discussing drug formulation and circulating total protein factors).
Therefore, WO’251 suggests the use of endothelin receptor A antagonists at doses to achieve a much lower blood concentration of the agonist than commonly approved for therapies for pulmonary arterial hypertension:
Accordingly, the methods and formulations of the present invention contemplate the use of ETA antagonists to achieve much lower blood concentrations than are commonly used for approved therapies for PAH
WO’251 at 16.
In certain examples, WO’251 discloses the following doses to maintain plasma levels of ambrisentan below about 10 ng/ml.:
Adult subjects with a history of cirrhosis and portal hypertension received ambrisentan at 1 day 50 µg s.c. q.d., 13 days 100 µg oral b.i.d., then 1 day 50 µg s.c. q.d. WO’251 at 40.
Adult subjects with a history of cirrhosis and portal hypertension received ambrisentan at 1 day 10 µg s.c. q.d., 13 days 14 µg oral b.i.d., then 1 day 10 µg s.c. q.d. WO’251 at 40.
Clarkson-Jones 2011
Clarkson-Jones 2011 generally discloses results from studies of the pharmacokinetics of zibotentan in mice, rats and dogs. The studies employed [14C]-zibotentan as the source of zibotentan.
Male and female Wistar rats (192-266 g) received oral administration of 3 and 10 mg/kg zibotentan, and 3 and 5 mg/kg zibotentan by iv route. Id. at 785.
Male and female Beagle dogs (8.1-11 kg) received 1 mg/kg oral and iv zibotentan. Id. at 785-786.
Male and female CD-1 mice (23-39g) received oral administration of 8 mg/kg zibotentan. Id. at 785-786.
No adverse effects from the administration of zibotentan were reported in Clarkson-Jones 2011. Clarkson-Jones 2011 further reports a number of metabolites of from the administration of zibotentan. See, e.g., Clarkson-Jones 2011 at Tables 4-7 and Figure 5, pages 793-795.
2003 FDA Guidance
The 2003 FDA Guidance generally discloses recommendations for those planning to assess the influence of hepatic impairment on the pharmacokinetics and pharmacodynamics of a drug. In particular, the 2003 FDA Guidance states:
If the effect of hepatic impairment on the PK of the drug is obvious (e.g., two-fold or greater increase in AUC), dosage adjustments should be recommended in labeling.
2003 FDA Guidance at pdf page 10 of 19.
Further, the 2003 FDA Guidance recommends reduced dosing for patients with hepatic impairment when concerns arise from drug toxicity:
A multiple-dose study is desirable when the drug or an active metabolite is known to exhibit nonlinear or time-dependent PK. Although the planned clinical dose is generally recommended as the appropriate dose to be used in the study, a reduced dose may be appropriate in patients with hepatic impairment if concern exists about drug toxicity in patients with increased blood levels.
Id. at pdf page 8 of 19 (emphasis added).
2005 FDA Guidance
The 2005 FDA Guidance generally discloses a method “for deriving the maximum recommended starting dose (MRSD) for first-in-human clinical trials of new molecular entities in adult healthy volunteers….” 2005 FDA Guidance at pdf page 4 of 30. In general, a new molecular entity is administered to test animal species in order to determine the no observed adverse effect levels (“NOAELs”). Id. at pdf page 6 of 30. The NOAELs are then converted to human equivalent doses (“HEDs”) using appropriate scaling factors. Id. Further, “[a] safety factor should then be applied to the HED to increase assurance that the first dose in humans will not cause adverse effects.” Id. at pdf page 7 of 30. “In practice, the MRSD for the clinical trial should be determined by dividing the HED derived from the animal NOAEL by the safety factor. The default safety factor that should normally be used is 10.” Id. at pdf page 10 of 30. However, a number of considerations apply which may result in raising or lowering the safety factor. See id. at pdf pages 13-15 of 30.
Moreover, in certain cases, FDA recommends further lowering the starting dose. For example, The 2005 FDA Guidance states that:
As previously stated, for purposes of initial clinical trials in adult healthy volunteers, the HED should ordinarily be calculated from the animal NOAEL. If the HED is based on an alternative index of effect, such as the pharmacologically active dose (PAD), this exception should be prominently stipulated in descriptions of starting dose calculations.
2005 FDA Guidance at 4 (emphasis added), and
Additionally, for certain classes of drugs or biologics (e.g., vasodilators, anticoagulants, monoclonal antibodies, or growth factors), toxicity may arise from exaggerated pharmacologic effects. The PAD in these cases may be a more sensitive indicator of potential toxicity than the NOAEL and might therefore warrant lowering the MRSD.
Id. at pdf page 15 of 30 (emphases added).
Claim 17 was Obvious at the Time of Filing
One of ordinary skill in the art at the time of filing seeking to design a protocol to study the combination of zibotentan and dapagliflozin would recognize that the dosing range of zibotentan was well explored. However, a subject with hepatic impairment may have reduced clearance and therefore may require a smaller dose of drug compared to a subject with normal liver function. See, for example, Tomkinson 2011 at Conclusion, page 10 or 11 (confirming the safety of single dose 10 mg zibotentan in subjects with hepatic impairment). One of ordinary skill in the art at the time of filing would be motivated to limit the highest dose to not reach 22.5 mg because of the adverse events observed from that dose. See supra discussion of Tomkinson 2011, citing Schelman et al. Moreover, one of ordinary skill in the art at the time filing would be aware of results showing dose-linear increase pharmacokinetics of zibotentan ranging from doses of 5-15 mg. See supra discussion of Tomkinson 2011, citing Ranson et al.
Turning to the lower end of the recited range, i.e., about 0.5 mg to less than 5 mg zibotentan, as an initial matter, one of ordinary skill in the art at the time of filing seeking to study the safety and efficacy of an endothelin A receptor antagonist in subjects with cirrhosis would be motivated to decrease the starting dose of the endothelin A receptor antagonist relative to the dose used in subjects without cirrhosis because WO’251 discloses numerous comorbidities that cirrhotic patients suffer from that affects the metabolism of the endothelin A receptor antagonist, which in turn results in higher plasma concentrations of the agonist in cirrhotic patients. See, e.g., WO’251 at 15-16. One having ordinary skill in the art at the time of filing would be motivated to avoid having high concentrations of the agonist in the plasma of cirrhotic patients because:
Regarding the safety, “These high concentrations may lead to the blockade of ETB receptor sites, which in turn leads to loss of intra-hepatic vasodilation and hence may aggravate the pressure in the portal venous system and induce fluid retention by the kidney.” WO’251 at 15.
Regarding the efficacy - “Such concentrations are too high to be effective in treating portal hypertension and in fact are counterproductive because they contribute to the loss of intra-hepatic vasodilation and hence may increase the pressure in the portal venous system and induce fluid retention by the kidney.” WO’251 at 14-15 (emphasis added).
Moreover, one of ordinary skill in the art at the time of filing would consider starting a clinical study to assess the safety of any drug for administration in subjects with hepatic impairment at a dose lower than indicated from data collected from healthy human subjects because the 2003 FDA Guidance recommends that “a reduced dose may be appropriate in patients with hepatic impairment if concern exists about drug toxicity in patients with increased blood levels.” 2003 FDA Guidance at pdf page 8 of 19 (emphasis added). One of ordinary skill in the art at the time of filing would have such concern about drug toxicity of zibotentan in cirrhotic patients because:
Tomkinson 2011 discloses that single dose studies of zibotentan administered to subjects with hepatic impairment resulted in increased AUC relative to control subjects, Tomkinson 2011 at Conclusion, page 10 of 11.
The 2003 FDA Guidance recommends that “if the effect of hepatic impairment on the PK of the drug is obvious (e.g., two-fold or greater increase in AUC), dosage adjustments should be recommended in labeling.” 2003 FDA Guidance at page 10 of 19,
Clarkson-Jones 2011 reports a number of metabolites of zibotentan whose toxicity were not evaluated in nonclinical studies. See, e.g., Clarkson-Jones 2011 at Tables 4-7 and Figure 5, pages 793-795 discussed above,
The 2005 FDA guidance warns that “for certain classes of drugs … (e.g., vasodilators …), toxicity may arise from exaggerated pharmacologic effects.” 2005 FDA Guidance at pdf page 15 of 30 (emphasis added).
Endothelin receptor antagonists exert a vasodilatory effect through antagonism of the endothelin receptor A. See WO’251 at 10-11, discussed above regarding claim 1.
Therefore, one having ordinary skill in the art at the time of filing would have a reasonable expectation of success in designing a method to treat liver cirrhosis using a combination of zibotentan and dapagliflozin, wherein the dose of zibotentan is about 0.5 mg to 20 mg, because 1) the combination was obvious at the time of filing for the reasons stated regarding claim 1, 2) the range of 5 mg – 22.5 mg zibotentan was known in the art, 3) WO’251 teaches that endothelin receptor antagonists are more effective at lower doses when treating portal hypertension, and 4) safety concerns regarding the administration of zibotentan to patients with hepatic impairment such as cirrhosis with portal hypertension indicate a lower starting dose.
Therefore, claim 17 was obvious at the time of filing.
Claim 24 was obvious over Zipprich 2020 in view of WO’251, Montalvo-Gordon 2020, Smeijer 2021, the 04/2021 FARXIGA® Label, Komoroski 2009, and 2003 FDA Guidance
Claim 24 is rejected under 35 U.S.C. 103 as being unpatentable over Zipprich 2020, in view of WO’251, Montalvo‐Gordon 2020, Smeijer 2021, FARXIGA® Label, revised 04/2021, pages 1-52, hereinafter the “04/2021 FARXIGA® Label”, B. Komoroski et al., “Dapagliflozin, a Novel SGLT2 Inhibitor, Induces Dose-Dependent Glucosuria in Healthy Subjects”, Clinical Pharmacology & Therapeutics, vol. 85, no. 5, pp. 520-526 (2009), hereinafter “Komoroski 2009”, and the 2003 FDA Guidance.
The previously cited references are relied upon as above.
Claim 24 recites the method of claim 1, wherein the composition comprises about 1 mg to about 10 mg dapagliflozin.
Zipprich 2020, WO’251, Montalvo-Gordon 2020, Smeijer 2021 and 2003 FDA Guidance do not explicitly teach a dose of about 1 mg to about 10 mg dapagliflozin.
However, one of ordinary skill in the art at the time of filing would have a reasonable expectation of success in selecting a range of about 1 mg to about 10 mg dapagliflozin for use in the method of claim 1 because:
the range of 2.5 mg – 10 mg zibotentan was known in the art (04/2021 FARXIGA® Label and Komoroski 2009), and
safety concerns regarding the administration of dapagliflozin to patients with hepatic impairment indicate a lower starting dose (2003 FDA Guidance).
04/21 FARXIGA® Label
The 04/2021 FARXIGA® Label discloses 5 mg and 10 mg administration of dapagliflozin tablets. 04/2021 FARXIGA® Label at 1. Regarding patients with hepatic impairment, the label discloses that dose adjustment is not recommended for patients with mild, moderate, or severe hepatic impairment. Id. at 15. However, the label recommends a benefit-risk assessment for the use of dapagliflozin in patients with severe hepatic impairment because “the safety and efficacy of dapagliflozin have not been specifically studied in this population [see Clinical Pharmacology (12.3)].” Id.
Regarding the pharmacokinetics of dapagliflozin in patients with hepatic impairment, the 04/2021 FARXIGA® Label discloses that:
In subjects with mild and moderate hepatic impairment (Child-Pugh classes A and B), mean Cmax and AUC of dapagliflozin were up to 12% and 36% higher, respectively, as compared to healthy matched control subjects following single-dose administration of 10 mg dapagliflozin. These differences were not considered to be clinically meaningful. In patients with severe hepatic impairment (Child-Pugh class C), mean Cmax and AUC of dapagliflozin were up to 40% and 67% higher, respectively, as compared to healthy matched controls [see Use in Specific Populations (8.7)].
04/2021 FARXIGA® Label at 18-19.
Komoroski 2009
Komoroski 2009 generally discloses results from the pharmacokinetics of dapagliflozin in healthy subjects. In particular, Komoroski 2009 discloses results from single and multiple ascending dose studies wherein the dose of dapagliflozin rose from 2.5 mg to up to 500 mg daily. See Komoroski 2009 at Abstract. Adverse events were reported in subjects receiving 2.5 mg dapagliflozin in both the single and multiple dose studies. Id. at 521. Furthermore, subjects receiving 2.5 mg dapagliflozin exhibited laboratory abnormalities in absolute neutrophils + bands, ALT, and potassium. Id. at 521-522. Other laboratory abnormalities were reported for other doses in total bilirubin, AST, BUN, and creatinine. Id. at 521-522. However, none of the abnormalities were considered clinically significant. Id.
Claim 24 was Obvious at the Time of Filing
One of ordinary skill in the art at the time of filing seeking to design a protocol to study the combination of zibotentan and dapagliflozin would recognize that the dosing range of dapagliflozin was well explored. First, one of ordinary skill in the art at the time of filing would review the 04/2021 FARXIGA® Label and find that 5 mg and 10 mg dapagliflozin dosages were recommended for patients with mild, moderate and severe hepatic impairment. 04/2021 FARXIGA® Label at 1 and 15. However, one having ordinary skill in the art at the time of filing would be aware that in cases of patients with severe hepatic impairment, mean Cmax and AUC of dapagliflozin were significantly elevated compared to healthy matched controls. Id. at 9. Based upon the known increased Cmax and AUC of dapagliflozin in patients with severe hepatic impairment, one having ordinary skill in the art at the time of filing would be motivated to decrease the dose of dapagliflozin for such patients because the 2003 FDA Guidance recommends a reduced dose in patients with hepatic impairment if concern exists about drug toxicity in patients with increased blood levels, 2003 FDA Guidance at 8, and in particular when the effect of hepatic impairment on the PK of the drug is obvious, 2003 FDA Guidance at 10.
Furthermore, one having ordinary skill in the art at the time of filing would be aware of the studies of the pharmacokinetics of dapagliflozin in healthy subjects reported in Komoroski 2009 that disclose 2.5 mg dapagliflozin elicited adverse events and laboratory abnormalities in values relating liver function (e.g., ALT) in healthy subjects. Komoroski 2009 at 521-522. Combined with the recommendation on the 04/2021 FARXIGA® Label to assess the benefit-risk of administration of dapagliflozin to patients with severe hepatic impairment, one having ordinary skill in the art at the time of filing would be motivated to further decrease the starting dose of dapagliflozin because the 2003 FDA Guidance recommends a reduced dose in patients with hepatic impairment if concern exists about drug toxicity in patients with increased blood levels, 2003 FDA Guidance at 8, and in particular when the effect of hepatic impairment on the PK of the drug is obvious, 2003 FDA Guidance at 10.
Therefore, one having ordinary skill in the art at the time of filing would have a reasonable expectation of success in designing a method to treat liver cirrhosis using a combination of zibotentan and dapagliflozin, wherein the dose of dapagliflozin is about 1 mg to 10 mg, because 1) the combination was obvious at the time of filing for the reasons stated regarding claim 1, 2) the range of 2.5 mg – 10 mg dapagliflozin was known in the art, and 3) safety concerns regarding the administration of dapagliflozin to patients with hepatic impairment indicate a lower starting dose.
Therefore, claim 24 was obvious at the time of filing.
Claims 74, 77, and 80-83 were obvious over Zipprich 2020 in view of WO’251, Montalvo-Gordon 2020, and Smeijer 2021
Claims 74, 77, and 80-83 are rejected under 35 U.S.C. 103 as being unpatentable over Zipprich 2020, in view of WO’251, Montalvo‐Gordon 2020, and Smeijer 2021.
Claim 74 recites a method of reducing the risk of variceal haemorrhage and/or death, or preventing and/or delaying progression of variceal haemorrhage and/or death, in a subject in need thereof, comprising administering to the subject a composition comprising a therapeutically effective amount of zibotentan and dapagliflozin.
Claim 77 recites a method of reducing the risk of cirrhosis decompensation or preventing and/or delaying progression of cirrhosis decompensation, in a subject in need thereof, comprising administering to the subject a composition comprising a therapeutically effective amount of zibotentan and dapagliflozin.
The previously cited references are relied upon as above.
Both claims 74 and 77 are related to the extent that they are generally directed to reducing the risk of cirrhosis decompensation and its complications. For example, the Specification explains that variceal hemorrhage and/or ascites are various decompensation events. See Specification at page 16, paragraph [0070] (listing “variceal hemorrhage, hepatic encephalopathy, and/or ascites” as various decompensating events).
WO’251 discloses that the major complications of cirrhosis, such as ascites and varices, are driven by portal hypertension:
Portal hypertension (also referred to as "increased portal pressure") is an abnormal increase in pressure of the portal venous system, which drains blood from the intestine, pancreas and spleen into the liver. Portal hypertension is of importance as it is the underlying abnormality leading to the major complications of cirrhosis, which account for most of the morbidity and mortality in patient with cirrhosis. These major complications include ascites and its complications (e.g. spontaneous bacterial peritonitis, refractory ascites, hepatorenal syndrome, dilutional hyponatremia), upper gastrointestinal bleeding from gastroesophageal varices, pulmonary arterial hypertension (referred to as Portopulmonary Hypertension), splenomegaly and thrombocytopenia, jaundice and hepatic encephalopathy, among others.
WO’251 at 1 (emphases added).
WO’251 discloses that these complications may be prevented and treated by reducing portal pressure through administration of selective endothelin receptor A antagonists:
The inventors have further found that the major complications of cirrhosis (e.g. ascites, variceal bleeding, hepatic encephalopathy and jaundice), can be prevented and treated by reducing portal pressure through the administration of selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).
WO’251 at 6 (emphasis added).
Montalvo‐Gordon 2020 discloses that administration of SGLT2 inhibitors eliminated ascites in patients with cirrhosis and diabetes. See supra discussion of Montalvo‐Gordon 2020 in section regarding the obviousness of claim 1.
Claims 74 and 77 were Obvious at the Time of Filing
One having ordinary skill in the art at the time of filing would have a reasonable expectation of success in developing a method of treating liver cirrhosis in a subject in need thereof, comprising administering a composition comprising a therapeutically effective amount of zibotentan and dapagliflozin for the reasons stated in the section regarding the obviousness of claim 1.
One having ordinary skill in the art at the time of filing would have a reasonable expectation of success in using such a method for reducing the risk of cirrhosis decompensation because WO’251 discloses that ascites and variceal bleeding “can be prevented … by reducing portal pressure through the administration of selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).” WO’251 at 6.
One having ordinary skill in the art at the time of filing would have a reasonable expectation of success in using such a method for reducing the risk of variceal haemorrhage because WO’251 discloses that variceal bleeding “can be … treated by reducing portal pressure through the administration of selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).” WO’251 at 6.
Therefore, claims 74 and 77 were obvious at the time of filing.
Claims 80 – 83 were Obvious at the Time of Filing
Regarding claims 80 and 81, these claims bear similarities to claim 2, wherein the subject has “features of portal hypertension”.
Claim 80 depends upon claim 74, and recites that the subject has features of portal hypertension. Likewise, Claim 81 depends upon claim 77, and recites that the subject has features of portal hypertension.
The method of claim 1, wherein the subject has features of portal hypertension, was discussed above in the section regarding the obviousness of claim 2. Those reasons apply here as well.
Therefore, for the reasons set forth in the above parent claims 74 and 77, as well as those set forth for claim 2, claims 80 and 81 were obvious at the time of filing.
Regarding claims 82 and 83, these claims bear similarities to claim 3, wherein the subject has “a HVPG greater than 5 mmHg”.
Claim 82 depends upon claim 74, and recites that the subject has a HVPG greater than 5 mmHg. Likewise, claim 83 depends upon claim 77, and recites that the subject has a HVPG greater than 5 mmHg.
The method of claim 1, wherein the subject has a HVPG greater than 5 mmHg, was discussed above in the section regarding the obviousness of claim 3. Those reasons apply here as well.
Therefore, for the reasons set forth in the above parent claims 74 and 77, as well as those set forth for claim 3, claims 82 and 83 were obvious at the time of filing.
Claims 84 and 85 were obvious over Zipprich 2020 in view of WO’251, Montalvo-Gordon 2020, Smeijer 2021, Tomkinson 2011, Clarkson-Jones 2011, 2003 FDA Guidance, and 2005 FDA Guidance
Claims 84 and 85 are rejected under 35 U.S.C. 103 as being unpatentable over Zipprich 2020, in view of WO’251, Montalvo‐Gordon 2020, Smeijer 2021, Tomkinson 2011, Clarkson-Jones 2011, the 2003 FDA Guidance, and the 2005 FDA Guidance.
Regarding claims 84 and 85, these claims bear similarities to claim 17, wherein the composition comprises “about 0.5 mg to about 20 mg zibotentan”.
Claim 84 depends upon claim 74, and recites that the composition comprises about 0.5 mg to about 20 mg zibotentan. Likewise, Claim 85 depends upon claim 77, and recites that the composition comprises about 0.5 mg to about 20 mg zibotentan.
The method of claim 1, wherein the composition comprises about 0.5 mg to about 20 mg zibotentan, was discussed above in the section regarding the obviousness of claim 17. Those reasons apply here as well.
Therefore, for the reasons set forth in the above parent claims 74 and 77, as well as those set forth for claim 17, claims 84 and 85 were obvious at the time of filing.
Claims 86 and 87 were obvious over Zipprich 2020 in view of WO’251, Montalvo-Gordon 2020, Smeijer 2021, the 04/2021 FARXIGA® Label, Komoroski 2009, and 2003 FDA Guidance
Claims 86 and 87 are rejected under 35 U.S.C. 103 as being unpatentable over Zipprich 2020, in view of WO’251, Montalvo‐Gordon 2020, Smeijer 2021, the 04/2021 FARXIGA® Label, Komoroski 2009, and the 2003 FDA Guidance.
Regarding claims 86 and 87, these claims bear similarities to claim 24, wherein the composition comprises “about 1 mg to about 10 mg dapagliflozin”.
Claim 86 depends upon claim 74, and recites that the composition comprises about 1 mg to about 10 mg dapagliflozin. Likewise, Claim 85 depends upon claim 77, and recites that the composition comprises about 1 mg to about 10 mg dapagliflozin.
The method of claim 1, wherein the composition comprises about 1 mg to about 10 mg dapagliflozin, was discussed above in the section regarding the obviousness of claim 24. Those reasons apply here as well.
Therefore, for the reasons set forth in the above parent claims 74 and 77, as well as those set forth for claim 24, claims 86 and 87 were obvious at the time of filing.
Secondary Considerations Relevant to all Claims
Secondary conditions, such as unexpected results, may be indicia of obviousness or nonobviousness. For example, a showing that the combination of zibotentan and dapagliflozin at the recited dosages unexpectedly resulted in superior patient outcomes may overcome the above prima facie case of obviousness of the instant claims. However, “[a] showing of unexpected results must be based on evidence, not argument or speculation. In re Mayne, 104 F.3d 1339, 1343-44, 41 USPQ2d 1451, 1455-56 (Fed. Cir. 1997)….” MPEP 2145.
Here, the Specification fails to provide any results from any of the claimed methods of treating liver cirrhosis. Instead, the only example provided in the Specification appears to be an overview of a protocol for a proposed clinical trial studying the claimed methods of treating liver cirrhosis. Because the Specification fails to disclose evidence resulting from any of the claimed methods of treating liver cirrhosis, the examiner cannot assess whether a secondary consideration, such as unexpected results, may overcome the above case of obviousness.
Prior Art Cited but not Applied
The prior art made of record and not relied upon is considered pertinent to applicant’s disclosure.
The July 2, 2021 record history of the clinical trial titled “Zibotentan and Dapagliflozin for the Treatment of CKD (ZENITH-CKD Trial) (ZENITH-CKD)”, ClinicalTrials.gov ID No. NCT04724837, pp. 1-51, last update posted July 6, 2021, retrieved from the Internet on January 13, 2026.
Conclusion
No claims are allowed.
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/C.E.R./ Examiner, Art Unit 1629
/JEFFREY S LUNDGREN/ Supervisory Patent Examiner, Art Unit 1629
1 Regarding dosing for systemic oral administration of Ambrisentan, see Zipprich 2020 at 555 (“The dose of Ambrisentan was chosen according to the recommended dose for treatment of pulmonary hypertension. Owing to safety aspects, regulatory authorities (Bundesministerium für Arzeneimittel und Medizinprodukte, BfArM) required an initial lower dose of 5 mg in the first 10 patients. The results were then reported back before the rest of the patients could be administered the higher 10 mg dose. Non-invasive blood pressure measurement, heart rate and peripheral oxygen saturation were measured throughout the whole study.”).
2 Regarding dosing for local administration of BQ-123, see Zipprich 2020 at 555 (“In the first substudy (local administration; n = 12), and on top of the catheterization of the hepatic vein in order to measure the hepatic venous pressure gradient (see below), a catheter was placed into the hepatic artery (see below). This allowed continuous local infusion of a selective ET-A antagonist (BQ-123)19 at increasing doses, that is, 10 minutes 300, 10 minutes 500, 3 minutes 1000 and 3 minutes 2000 nmol min−1, and simultaneous and continuous measurement of the hepatic arterial blood flow with a Doppler wire.9, 20 The increasing doses were chosen because of safety reasons.”).
3 Ambrisentan administration for the treatment of cirrhosis was exemplified in Zipprich 2020, discussed supra.
4 For example, embodiments include “the treatment of portal hypertension”, WO’251 at 16, “in the treatment of portal hypertension associated with cirrhosis”, id. at 18, “the treatment of portopulmonary hypertension”, id. at 19, “the treatment of ascites”, id. at 19, “the prophylactic treatment of variceal bleeding”, id. at 19, “the treatment of variceal bleeding”, id. at 20, “the treatment of jaundice”, id. at 20, “the treatment of hepatic encephalopathy”, id. at 21, “the prophylactic treatment of the progression of cirrhosis”, id. at 21, “the prophylactic treatment of the progression of liver fibrosis”, id. at 21, “the treatment of Non-Alcoholic Steatohepatitis (NASH)”, id. at 22, “the treatment of subjects suffering from Non-Alcoholic Steatohepatitis (NASH) and reducing the progression of liver fibrosis and/or reduction of portal hypertension”, id. at 22.
5 A copy of the ClinicalTrials.gov ID No. NCT04724837, pp. 1-51, version 5, last update posted July 6, 2021, retrieved from the Internet on February 11, 2026, is attached hereto and referenced later in this office action.