Prosecution Insights
Last updated: April 19, 2026
Application No. 18/555,776

METHOD FOR OBTAINING RIFAPENTINE WITH A NEW CRYSTALLINE FORM

Non-Final OA §102§112
Filed
Oct 17, 2023
Examiner
NEAGU, IRINA
Art Unit
1629
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Interquim S A De C V
OA Round
1 (Non-Final)
47%
Grant Probability
Moderate
1-2
OA Rounds
2y 9m
To Grant
99%
With Interview

Examiner Intelligence

Grants 47% of resolved cases
47%
Career Allow Rate
324 granted / 696 resolved
-13.4% vs TC avg
Strong +58% interview lift
Without
With
+58.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
52 currently pending
Career history
748
Total Applications
across all art units

Statute-Specific Performance

§101
1.5%
-38.5% vs TC avg
§103
39.5%
-0.5% vs TC avg
§102
11.7%
-28.3% vs TC avg
§112
23.1%
-16.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 696 resolved cases

Office Action

§102 §112
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. DETAILED ACTION Claims 1-8 are pending in the instant application. Claims 1-8 are being examined on their merits herein. Priority The instant application is a National Stage entry of International Patent Application PCT/MX2021/050020, filed on 21 April 2021. Information Disclosure Statement The information disclosure statement (IDS) submitted on 17 October 2023 is acknowledged and considered. Objection to the Specification The Specification is objected to because on page 11 it recites “ Figures 2 to 6 show the comparison of the X-ray powder diffraction pattern of the crystalline form of Rifapentine of the present invention with the reflections of the Crystalline Forms reported in WO 90/00553, WO 92/00302, Zhou, Li & Zheng, J. Molecular Structure (2010) and Zhou, Li &Zheng ” ; yet , no such comparison is presented - in Figures or otherwise . T he Specification, page 11, refers to Figures 2-6. T here are 3 Figures in this application, Figures 1-3; Figure 1 is diffraction pattern of the crystalline form of Rifapentine obtained according to the present invention. Figure 2 shows the synthesis scheme of Rifapentine according to the present invention. Figure 3 illustrates the molecular configuration of Rifapentine and the atom numbering scheme. There are no Figures 4, 5 or 6. Appropriate correction is required. Objection to the Drawings The drawings submitted on 17 October 2023 are objected to because the structures and text in Figure 2 are unclear. Applicant is to provide legible text and structures for Figure 2. Appropriate correction is required. Claim objection Claims 3, 4 are objected to because the terms “squeezing” (of a solid?) and “re-pulping” (of a product) seem incorrect/unusual translations into English of chemical terms. Applicant is required to provide the appropriate corresponding chemical terms in English. Claim 8 is objected to because the term “composition having the pure crystalline form” should read – composition comprising the pure crystalline form--. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.— The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 3-7 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 3 is drawn to a process for the preparation of the pure crystalline form of rifapentine comprising a number of steps; the claim should recite a pure crystalline form . Claim 3 fails to define the characteristics of the pure crystalline form of rifapentine ; as such, it is unclear whether claims 3-7 are related to claims 1, 2. The claims are generally narrative and indefinite, failing to conform with current U.S. practice. They appear to be a literal translation into English from a foreign document and are replete with grammatical and idiomatic errors. Claim 3, as written, seems to be an experimental procedure, written for an organic chemist working in a laboratory, with little regard for explaining how the steps relate to one another. For example, the second step listed is “adding rifamycin S and glacial acetic acid”, without indicating what is being added to what. Another step listed is “adding a solution […] at a temperature for 16 hours ’ - which begs the question whether the addition actually lasts for 16 hours. Claim 3 also recites cooling the reaction mixture, without defining a reaction mixture. Claim 3 recites filtering and washing the product, without defining what is the product; claim 3 further recites squeezing (what does that mean, in English, squeezing a product?) and dry vacuum, without explaining what is being squeezed (?). The claim recites “and carry out re-pulping of the product”, without explaining which product the claim refers to and what does it mean, in English, to re-pulp a chemical compound/product. Claims 3-7 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA), second paragraph, as being incomplete for omitting essential steps, such omission amounting to a gap between the steps. See MPEP § 2172.01. Claim 3 is drawn to a process for the preparation of a pure crystalline form of rifapentine, yet the claim fails to recite a step of crystallization or recrystallization, without which a crystalline form cannot be obtained. The omitted steps are: crystallization or recrystallization of rifapentine from a solvent or mixture of solvents. Claim 4 is indefinite because it depends on claim 3 and recites “the crude product”, it recites “dissolving the solid”, yet claim 3 does not recite a crude product, or a solid. As such, there is insufficient antecedent basis for the terms “the crude product”, “the solid”, of claim 4, in claim 3. Claim 4 recites washing with a mixture ethanol/water, without explaining what is actually washed. Claim 4 recites 2 volumes of water, without explaining what constitutes one volume or two volumes of water. Claim 5 depends on claim 3 and recites “the re-pulping stage in water”, yet claim 3 does not recite a re-pulping stage in water. As such, there is insufficient antecedent basis for the term “the re-pulping stage in water” of claim 5, in claim 3. Claim 5 is indefinite because it recites 8 volumes of water, or 1 volume of water, without explaining what constitutes one volume or 8 volumes of water. Claim 6 depends on claim 3 and recites the yield of crude rifapentine; yet, it is unclear what constitutes crude rifapentine (where exactly in the process of claim 3 it is obtained), and it is unclear whether the yield in claim 6 refers to crude rifapentine before the step ”purify crude rifapentine” in claim 3 . Claim 7 depends on claim 3 and recites “pure rifapentine”; yet claim 3 does not recite pure rifapentine- rather, it recites pure crystalline form of rifapentine. As such, it is unclear what the yield in claim 7 refers to. Appropriate clarification of the claim language is required. Claim Rejections- 35 USC 10 2 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claim s 1, 2, 8 are rejected under 35 U.S.C. 102 (a)(1) as being anticipated by Zhou et al. (Front. Chem. Eng. China 2010, 4(1), 65-69, cited in IDS) . Zhou teaches (Figure 3) a crystalline form of rifapentine, with a distinct X-ray powder diffraction pattern (XRPD) similar to the one in the instant application, wherein the crystalline form of rifapentine is obtained by recrystallization from ethanol (preparation by dissolving predetermined amounts of rifapentine in 30 mL ethanol, page 66, left column, point 2.2). "When the PTO shows a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not." In re Spada, 911F.2d 705, 709, 15 USPO2d 1655, 1658 (Fed. Cir. 1990). Recrystallization of rifapentine from ethanol is reported by Zhou. As such, the claimed limitations appears to be met by the prior art. Applicants are reminded that the office does not have the facilities and resources to provide the factual evidence needed in order to establish that the product of the prior art does not possess the same material, structural and functional characteristics of the claimed method. In the absence of evidence to the contrary, the burden is on the applicant to prove that the function of the product is different from those taught by the prior art and to establish patentable differences. See In re Best 562F.2d 1252, 195 USPQ 430 (CCPA 1977) and Ex parte Gray 10 USPQ 2d 1922 (PTO Bd. Pat. App. & Int. 1989). As such, Zhou anticipates instant claims 1, 2, 8. Claim s 1, 2, 8 are rejected under 35 U.S.C. 102 (a)(1) and 102 (a)(2) as being anticipated by Das et al. (IN 202021050032, cited in PTO-892) . Zhou teaches a crystalline form of rifapentine, with a distinct X-ray powder diffraction pattern (XRPD) similar to the one in the instant application, wherein the crystalline form C2 of rifapentine is obtained by recrystallization from ethanol (preparation by dissolving predetermined amounts of rifapentine in ethanol, Description, last 15 lines). "When the PTO shows a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not." In re Spada, 911F.2d 705, 709, 15 USPO2d 1655, 1658 (Fed. Cir. 1990). Recrystallization of rifapentine from ethanol is reported by Das. As such, the claimed limitations appears to be met by the prior art. Applicants are reminded that the office does not have the facilities and resources to provide the factual evidence needed in order to establish that the product of the prior art does not possess the same material, structural and functional characteristics of the claimed method. In the absence of evidence to the contrary, the burden is on the applicant to prove that the function of the product is different from those taught by the prior art and to establish patentable differences. See In re Best 562F.2d 1252, 195 USPQ 430 (CCPA 1977) and Ex parte Gray 10 USPQ 2d 1922 (PTO Bd. Pat. App. & Int. 1989). As such, Das anticipates instant claims 1, 2, 8. Claim s 1, 2, 8 are rejected under 35 U.S.C. 102 (a)(1) and 102 (a)(2) as being anticipated by Occelli et al. ( US 5,306,715 , cited in PTO-892) . Occelli teaches a crystalline form of rifapentine, obtained by recrystallization from ethanol (preparation by dissolving predetermined amounts of rifapentine in ethanol, column 1, lines 44-53 ). "When the PTO shows a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not." In re Spada, 911F.2d 705, 709, 15 USPO2d 1655, 1658 (Fed. Cir. 1990). Recrystallization of rifapentine from ethanol is reported by Occelli . As such, the claimed limitations appears to be met by the prior art. Applicants are reminded that the office does not have the facilities and resources to provide the factual evidence needed in order to establish that the product of the prior art does not possess the same material, structural and functional characteristics of the claimed method. In the absence of evidence to the contrary, the burden is on the applicant to prove that the function of the product is different from those taught by the prior art and to establish patentable differences. See In re Best 562F.2d 1252, 195 USPQ 430 (CCPA 1977) and Ex parte Gray 10 USPQ 2d 1922 (PTO Bd. Pat. App. & Int. 1989). As such, Occelli anticipates instant claims 1, 2, 8. Conclusion Claims 1- 8 are rejected. Any inquiry concerning this communication or earlier communications from the examiner should be directed to FILLIN "Examiner name" \* MERGEFORMAT IRINA NEAGU whose telephone number is FILLIN "Phone number" \* MERGEFORMAT (571)270-5908 . The examiner can normally be reached FILLIN "Work Schedule?" \* MERGEFORMAT Mon-Fri 8-5 . Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, FILLIN "SPE Name?" \* MERGEFORMAT JEFFREY S. LUNDGREN can be reached at FILLIN "SPE Phone?" \* MERGEFORMAT (571)272-5541 . The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /IRINA NEAGU/ Primary Examiner, Art Unit 1629
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Prosecution Timeline

Oct 17, 2023
Application Filed
Mar 28, 2026
Non-Final Rejection — §102, §112 (current)

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Prosecution Projections

1-2
Expected OA Rounds
47%
Grant Probability
99%
With Interview (+58.1%)
2y 9m
Median Time to Grant
Low
PTA Risk
Based on 696 resolved cases by this examiner. Grant probability derived from career allow rate.

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