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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 12/23/2025 has been entered.
Claim Status
Claims 2 and 5 have been cancelled and claims 1 has been amended, as requested in the amendment filed on 12/23/2025. Following the amendment, claims 1, 3-4, and 6 are pending in the instant application.
Claims 1, 3-4, and 6 are under examination in the instant office action.
Claim Interpretation
In in view of the instant claim amendments, independent claim 1 is being interpreted as a method of radio labeling a monoclonal antibody wherein (i) a hydroxamate ligand is exposed to a solution that comprises 89Zr and oxalic acid to yield 89Zr in oxalate form, (ii) the 89Zr in oxalate form is converted into 89Zr in chloride form which comprises less than 83 mM oxalate, and (iii) labelling a monoclonal antibody wherein the antibody is reacted with the 89Zr in chloride form comprising less than 83 mM oxalate to yield a radio-labeled antibody. Additionally, the fluoride/NaF (claims 3-4) is implicated in the purification/reaction to obtain 89Zr in oxalate form, and is not specifically implicated in the conversion to 89Zr in chloride nor the labeling reaction itself.
Claim Rejections - 35 USC § 112 - Maintained
Claims 1, 3-4, and 6 were rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, regarding scope of enablement. Claim 1 has been amended to recite that the 89Zr in oxalate form is converted into 89Zr in chloride form comprising less than 83 mM oxalate prior to radio labeling the antibody, which is enabled by the instant specification. As such, the rejection of claims 1, 3-4, and 6 under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, regarding scope of enablement, is withdrawn.
Claim Rejections - 35 USC § 112 - Maintained
Claims 1, 3-4, and 6 stand as 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.
With regard to claim 1, the claim as currently amended is still considered to be ambiguous. The claim is drawn to a method for radio labeling monoclonal antibodies wherein line 2 recites “preparing an 89Zr binding conjugate” and lines 6-7 recites “labeling the monoclonal antibody to form a bond conjugate comprising the 89Zr binding conjugate”. The identity of both the “89Zr binding conjugate” and the “bond conjugate” in the context of the method is ambiguous. It is unclear as to if “89Zr binding conjugate” refers to 89Zr in oxalate form, or if it is intended to refer to 89Zr in chloride form. It is suggested that Applicant remove recitations of “89Zr binding conjugate” and describe the method using clearer terms such as “89Zr in oxalate form” or “89Zr in chloride form” to clearly delineate the different method steps/reactions. Additionally, as presented, it appears as though the “89Zr binding conjugate” is referring to 89Zr in oxalate form. However, that would indicate that the “bond conjugate” comprises said 89Zr in oxalate form. It is noted that in radio labeling macromolecules, the 89Zr in oxalate form is being converted to chloride form, wherein the chloride form then complexes with a chelator (e.g., deferoxamine as recited in claim 6) to yield an 89Zr4+-Chelator complex which is then attached to said macromolecule. Without the recitation of a chelator in independent claim 1, it is not clear what additional steps may be required to actually perform the recited method to yield a radio labeled antibody.
Additionally, with regard to claim 6, the claim recites the limitation "the conjugate" in line 1. It is noted that independent claim 1, from which claim 6 depends, recites “an 89Zr binding conjugate” and “a bond conjugate”. As such, it is unclear as to what “the conjugate” in claim 6 is referring to and the presence of multiple possibilities (89Zr in oxalate form, 89Zr in chloride form, or the bond conjugate) renders the claims indefinite owed to multiple interpretations. For the purposes of examination, claim 6 is being interpreted such that “the conjugate” refers to the labeled monoclonal antibody (i.e., “bond conjugate”).
Claim Rejections - 35 USC § 103 - Maintained
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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
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.
With regard to the below-listed claim rejections, it is noted that in view of the amendment of claim 1, the teachings of Holland regarding the production of [89Zr]Zr-chloride (i.e., 89Zr in chloride form) from [89Zr]Zr-oxalate (i.e., 89Zr in oxalate form) are expanded upon as detailed below, and the teachings of Meijs has been removed as they are no longer relied upon; the rejections therefore rely on fewer than all of the previously cited references, but rely on the same teachings thereof provided in the previous Office Action. As such, the updated rejections do not constitute new grounds of rejection.
Claims 1 and 6 stand as rejected under 35 U.S.C. 103 as being unpatentable over non-patent literature by Holland et. al. (Nuclear Medicine and Biology, 2009, 36, 729-739; previously cited on PTO-892; herein after referred to as "Holland") in view of non-patent literature by Vosjan et. al. (Nature Protocols, 2010, 5(4), 739-743; previously cited on PTO-892; herein after referred to as "Vosjan"), and EP 0035765 A2 (previously cited on PTO-892; herein after referred to as “Yokoyama”).
With regard to claim 1, Holland teaches 89Zr was isolated in high radionuclidic and radiochemical purity (>99.99%) as [89Zr]Zr-oxalate by using a solid-phase hydroxamate resin with >99.5% recovery of the radioactivity; new methods for the facile production of [89Zr]Zr-chloride are also reported and radiolabeling studies using the trihydroxamate ligand desferrioxamine B (DFO) gave 100% radiochemical yields in <15 min at room temperature, and in vitro stability measurements confirmed that [89Zr]Zr-DFO is stable with respect to ligand dissociation in human serum for >7 days (Abstract). 89Zr was purified from the 89Y target material by use of a hydroxamate resin; irradiated 89Y-foil target was dissolved in 4x0.5 ml fractions of 6 M HCl(aq.), H2O2 was added to ensure complete oxidation, the solution was diluted with water to a concentration of <2 M HCl(aq.), then transferred to the hydroxamate column (i.e., hydroxamate ligand) (Pages 730-731). After loading the 89Zr activity, the column was washed with 2 M HCl(aq.) (4x2.5 ml) and water (4x2.5 ml) to remove the soluble Y(III) ions and other impurities and the 89Zr activity was slowly eluted with 5 successive portions of 1.0 M oxalic acid (4x0.5 ml, and 1x1.0 ml, elution time >2 min. for the first two fractions; i.e., contacting hydroxamate ligand with 89Zr and oxalic acid to yield [89Zr]Zr-oxalate) (Page 731, Column 2, Paragraph 1). [89Zr]Zr-oxalate solution in 1.0 M oxalic acid was loaded
onto an activated Waters Sep-pak Light QMA strong anion exchange cartridge (an acrylic acid/acrylamide copolymer on Diol silica; surface functionality: –C(O)NH(CH2)3N(CH3)3+Cl–, 300 Å pore size, 37–55 μm particle size, 0.22 mmol/g ligand density), pre-washed with 6 ml MeCN, 10 ml 0.9% saline and 10 ml water (chelex) (Page 732; Section 2.6). In all experiments >99.9% of the 89Zr activity remained trapped on the cartridge and the cartridge was then washed with water (>40 ml, chelex) and eluted with 1.0 M HCl(aq.) (300–500 μl; i.e., yielding [89Zr]Zr-chloride) wherein the amount of residual oxalic acid was estimated by collecting the eluate in a pre-weighed glass culture tube, and re-weighing after boiling the solution to dryness at 110–120 °C for 10 min; from the calculated mass of oxalic acid loaded onto the QMA cartridge, the estimated residual amount after elution was <0.2% (Id.). Thus, if 1 M oxalic acid was loaded onto the column, the residual oxalic acid after conversion to [89Zr]Zr-chloride is <0.002 M (i.e., <2 mM). The [89Zr]Zr-chloride can be reconstituted in either water, 0.9% saline or 0.1 M HCl(aq.) (Id.). [89Zr]Zr-DFO was prepared by the complexation of either [89Zr]Zr-oxalate (in 1.0 M oxalic acid) or [89Zr]Zr-chloride [in 0.1 M HCl(aq.)] with DFO; aliquots of either [89Zr]Zr-oxalate or [89Zr]Zr-chloride (typically <20 μl, 300–500 μCi) were diluted in 100 μl of either water or 0.9% saline in 1.8-ml centrifuge tubes and the excess 1.0 M oxalic acid or 0.1 M HCl was neutralized by adding the appropriate volume of Na2CO3(aq.) [1.0 M or 0.1 M in water] and the pH adjusted to 7–8 with <1-μl portions of 0.1 M HCl(aq.) and 0.1 M Na2CO3(aq.), after which DFO was added (Page 732, Column 2, Paragraph 2); i.e., the 89Zr in oxalate and/or chloride form was buffered prior to any conjugation reaction. Although the [89Zr]Zr-oxalate solution is suitable for complexation reactions involving the DFO ligand, oxalic acid is highly toxic (due to decalcification of blood and acute renal failure due to the obstruction of kidney tubules by calcium oxalate) and must be removed before performing any in vitro or in vivo studies; and thus the authors investigated methods regarding [89Zr]Zr-chloride (Page 736, Column 1; First Full Paragraph). Stability results demonstrate that DFO is a suitable choice of ligand for complexation and conjugation of 89Zr (IV) ions (i.e., oxalate and/or chloride form) to biologically active vectors such as mAbs (Page 736, Column 2, Paragraph 2). In contrast to [89Zr]Zr-oxalate, the [89Zr]Zr-chloride in 0.1 M HCl(aq.) was found to react rapidly with
phosphate and in PBS solution, insoluble species form which remain at the origin of the ITLC experiments; in this respect, [89Zr]Zr-chloride behaves in a similar way to [86/90Y]Y-chloride, and it is anticipated that radiolabeling experiments with [89Zr]Zr-chloride may best be achieved in
acetate buffers at pH 4.5–6.0 (Id.). Thus, Holland indicates that both [89Zr]Zr-oxalate and [89Zr]Zr-chloride can be used in conjugation reactions (wherein the pH of the chloride form solution should be adjusted to 4.5-6.0), including conjugation to macromolecules such as monoclonal antibodies, wherein DFO is a suitable ligand for complexation and conjugation of 89Zr (IV) ions (i.e., oxalate and/or chloride form) wherein conversion to chloride form may be preferred as the conversion removes 99.8% of highly toxic oxalic acid (which must be removed prior to any in vitro or in vivo studies).
Holland does not explicitly detail the conjugation of 89Zr to a macromolecule/monoclonal antibody. This deficiency is remedied by Vosjan and Yokoyama.
Vosjan discloses the step-by-step procedure for the facile radiolabeling of mAbs or other proteins with 89Zr using p-isothiocyanatobenzyl-desferrioxamine (Df–Bz–NCS) wherein Df–Bz–NCS is first coupled to the lysine–NH2 groups of a mAb at pH 9.0 (pre-modification; i.e., binding conjugate which comprises deferoxamine), followed by purification using gel filtration, after which the pre-modified mAb is labeled at room temperature by the addition of [89Zr]Zr-oxalic acid solution (i.e., 89Zr in oxalate form) followed by purification using gel filtration (Abstract). Specifically, steps 9-12 of the disclosed protocol detail the concentration of the oxalic acid solution; the final concentration of oxalic acid present in the reaction vial of step 11 is ~0.1 M (i.e., oxalic acid concentration is <1 M; 89Zr in oxalate form is buffered prior to reaction with monoclonal antibody); the stock oxalic solution of 1 M was heavily diluted to achieve radio labeling of typically >85% (Page 741; Steps 9-12). Thus, Vosjan discloses a method for radio labeling monoclonal antibodies with 89Zr (i.e., using 89Zr in oxalate form) wherein the method comprises buffering an 89Zr binding conjugate (i.e., 89Zr in oxalate form) then contacting the buffered 89Zr binding conjugate with a monoclonal antibody itself and/or mAb-Df-Bz-NCS) to yield a radio labeled monoclonal antibody. Thus, Vosjan discloses a radio labeling method wherein Df is first conjugated to an antibody via a thiol, and 89Zr in oxalate form is then exposed
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to the modified antibody wherein 89Zr complexes with Df (see Figure 1 below).
Yokoyama teaches a radioactive diagnostic agent and a non-radioactive carrier therefor; the invention relates to a radioactive diagnostic agent comprising deferoxamine, and a physiologically active substance and a radioactive metallic element bonded thereto, and a non-radioactive carrier comprising deferoxamine, and a physiologically active substance bonded thereto and being useful for preparation of said radioactive diagnostic agent (Page 1). The invention describes the preparation of human serum albumin-combined deferoxamine (i.e., deferoxamine modified serum albumin) as follows (Page 9, Example 1):
(i) Deferoxamine was dissolved in a mixture of 0.01 M phosphate buffer and 0.15 M aqueous sodium chloride solution (pH 7.4 ) (hereinafter referred to as "PBS") to make a concentration of 1.2 x 10-4 mol/ml. To the resultant solution, glutaraldehyde (25 % aqueous solution) was added to make an equimolar concentration to deferoxamine and, after 10 minutes, stirred at room temperature to give a solution (A).
(ii) Separately, human serum albumin (lyophilized; 266 mg) was dissolved in PBS (20 ml) to give a solution (B).
(iii) The solution (B) was admixed with the solution (A) (0.3 ml) at a temperature of 0 to 4°C, and stirring was continued at the same temperature as above for about 1 hour. To the resultant mixture, sodium borohydride (5 mg) was added, and stirring was further continued at a temperature of 0 to 4°C for about 1 hour, whereby reduction proceeded. The reaction mixture was subjected to column chromatography on Sephadex G-50 (5 x 20 cm) using PBS as an eluting solution for elimination of unreacted materials, etc. to give a human serum albumin-combined deferoxamine solution as a pale-yellow clear solution.
Thus, Yokoyama teaches direct conjugation of deferoxamine to a macromolecule. For labeling of the non-radioactive carrier (e.g., deferoxamine) with a radioactive metallic element (e.g., 67Ga ), 99m Tc, 111In, 201Tl), such carrier may be treated with the radioactive metallic element in an appropriate form, usually in an aqueous medium; when, for instance, the radioactive metallic element is Ga, the carrier may be treated with 67Ga in the form of gallium chloride in an aqueous medium and, when required, an oxidizing agent or a reducing agent may be present in the aqueous medium for producing an atomic valency of the radioactive metallic element which is necessitated for formation of a chelating bond (Page 7).
It would have been prima facie obvious to one of ordinary skill in the art at the time the invention was followed that that the methods of Holland could be combined with the methods of Vosjan/Yokoyama to yield a method of radio labeling a monoclonal antibody comprising (i) contacting a solution of 89Zr and oxalic acid with a hydroxamate ligand (e.g., resin/column) to obtain 89Zr in oxalate form (as suggested by Holland), (ii) converting 89Zr in oxalate form chloride form in order to remove/reduce oxalic acid concentration (as suggested by Holland, wherein Vosjan also discloses reducing oxalic acid concentrations for conjugation), and (iii) contacting the 89Zr in chloride form with a monoclonal antibody to yield a radio labeled monoclonal antibody (as suggested by the combination of Holland and Vosjan). One of ordinary skill in the art would have been motivated to combine the teachings of the references in order to develop an efficient conjugation method wherein excess oxalic acid (>98.8%), which is highly toxic, is removed prior to conjugation as suggested by Holland. It is further noted, that one of ordinary skill in the art would have had a reasonable expectation of success as conjugation methods using 89Zr are well established in the art, and Holland discloses that the chloride form is suitable for use in addition to the oxalate form when the pH of the chloride from solution is properly adjusted to 4.5-6.0 prior to conjugation to a macromolecule; subsequently it would also be reasonably expected that the chloride form could be complexed with Df and then added to a macromolecule (e.g., an antibody) as suggested by the methods of Holland, Vosjan, and Yokoyama, which together suggest that DFO is a suitable ligand for complexation and conjugation of 89Zr (IV) ions (i.e., oxalate and/or chloride form) wherein the conjugation of Df to a macromolecule may be direct, or an antibody could be pre-modified with Df. Thus, the combination of prior art elements according to known methods would reasonably be expected to yield predictable results in view of the teachings detailed above.
With regard to claim 6, it is noted that Holland teaches [89Zr]Zr-DFO (DFO is Desferol, which is also known as deferoxamine). Furthermore, Vosjan teaches discloses the step-by-step procedure for the facile radiolabeling of mAbs or other proteins with 89Zr using p-isothiocyanatobenzyl-desferrioxamine (Df–Bz–NCS).Yokoyama also teaches radio labeling macromolecules using chelator Df as a carrier. Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art at the effective filing date of the invention as evidenced by the references.
Claims 3-4 stand as rejected under 35 U.S.C. 103 as being unpatentable over non-patent literature by Holland et. al. (Nuclear Medicine and Biology, 2009, 36, 729-739; previously cited on PTO-892; herein after referred to as "Holland") in view of non-patent literature by Vosjan et. al. (Nature Protocols, 2010, 5(4), 739-743; previously cited on PTO-892; herein after referred to as "Vosjan"), and EP 0035765 A2 (previously cited on PTO-892; herein after referred to as “Yokoyama”), as applied to claims 1 and 6 above, and in further view of non-patent literature by Trubert et. al. (Analytica Chimica Acta, 1998, 374, 149-158; previously cited on PTO-892; herein after referred to as “Trubert”).
With regard to claim 3, the method of claim 1 is rendered obvious by the combination of Holland, Vosjan, and Yokoyama. However, none of the cited references explicitly disclose that the 89Zr/oxalic acid solution comprises fluoride. This deficiency is remedied by Trubert.
Trubert is a study focusing on the adsorption properties of Zr(IV), Hf(IV), Nb(V), Ta(V) and Pa(V) towards a strong basic macroporous anion exchanger in extended to HF-HCl mixtures, in order to define fast and efficient separation schemes (Page 149, Column 1, Paragraph 1). Experiments were carried out, using both static (batch technique) and dynamic conditions (column chromatography in the elution mode) and it is noted that elements in the oxidation state IV (Hf, Zr) as well as oxidation state V (Nb, Ta, Pa) are known to have a great tendency towards hydrolytic polymerization; it is also known that, when working at trace level, the formation of hydrolysis products (mono- and polynuclear) can be avoided by the presence of the fluoride anion even at low acidity, which ensures a satisfactory reproducibility of the chemical reactions studied (Page 150, Column 1, Paragraphs 1-2). According to Fig. 1, whatever the HF concentration, the Kd values of Zr and Hf decrease drastically with increase in HCl concentration; in 0.5 M HF, the Kd values of Zr and Hf decrease from 4x104 to 30 cm3 g-1 in 0.8 M HCl (Page 154, Column 1, Paragraph 4). Since in pure HCl medium (in the same range of concentration) no adsorption occurs, the presence of fluoride anions favors the formation of adsorbable complexes, probably negatively charged and additionally, according to
Fig. 1, the range of HCl concentration where the Kd values of Zr and Hf are larger than 100, increases with increasing HF concentration; fluoride ions, on one hand, allow the formation of stable anionic complexes, and on the other avoid hydrolysis phenomena (Id.). Thus, Trubert suggests that the presence of fluoride ions at low pH (e.g., in HCl solutions) favors the formation of adsorbable complexes and prevents hydrolysis.
Thus, it would have been prima facie obvious to one of ordinary skill in the art that the method rendered obvious by Holland, Vosjan, and Yokoyama could have been further modified such that in the step for obtaining 89Zr in oxalate form, Zr89 after exposure to a hydroxamate ligand (e.g., hydroxamate column, an anion-exchanger) could be eluted with an HCl/oxalic acid solution as suggested by Holland, wherein fluoride is also present (e.g., by adding HF). One of ordinary skill in the art would have been motivation to make such a modification in order to improve adsorption and prevent hydrolysis, with a reasonable expectation of success as suggested by Trubert. Thus, the combination of prior art elements according to known methods would be expected to yield predictable results with a reasonable expectation of success, as Trubert teaches the advantages of Zr adsorption, complexation, and hydrolysis in the presence fluoride ions in anion exchange chromatography.
With regard to claim 4, it is noted that none of the recited references explicitly indicate the use of NaF to provide fluoride 89Zr/oxalic acid solution. However, Trubert generally suggests that the presence of fluoride ions is beneficial for Zr adsorption, complexation, and preventing hydrolysis ((Page 150, Column 1, Paragraphs 1-2; Page 150, Column 1, Paragraphs 1-2). Thus, one of ordinary skill in the art would recognize that any source of free fluoride would be expected to have similar effects, and one of ordinary skill in the art would further recognize that a fluoride-containing ionic salt such as NaF would more efficiently dissociate to form free fluoride compared to HF as used by Trubert, for example. As such, one of ordinary skill in the art would recognize that the replacement of HF with NaF would be expected to have similar effects as it is still able to dissociate and provide free fluoride ions in solution, which would be expected have the same effects as fluoride ions provided by the dissociation of HF. Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art at the effective filing date of the invention as evidenced by the references.
Response to Arguments
It is noted that no specific arguments with regard to the claim rejections of record have been provided. On Page 7 of Remarks (12/23/2025), Applicant requested reconsideration of the rejections of record in view of the amended claims and prosecution on the merits of the amended claims pursuant to the request for continued examination. It was asserted that the amendment “is supported by the specification, overcomes the 112 rejections, and renders the pending claims non-obvious in view of the art of record” without any arguments to support this assertion. Applicant’s claim amendments have been considered, and have been fully addressed above wherein the claim rejections under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite and under 35 U.S.C. 103 as being unpatentable over Holland, Vosjan, and Yokoyama, and/or in further view of Trubert are maintained.
Conclusion
Claims 1, 3-4, and 6 are pending. Claims 1, 3-4, and 6 are rejected. No claims are allowed.
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/ALYSSA RAE STONEBRAKER/Examiner, Art Unit 1642
/SAMIRA J JEAN-LOUIS/Supervisory Patent Examiner, Art Unit 1642