Office Action 3: Non-Final Rejection (2023-06-13)
Rejection types: 103 - Obviousness, 112 - Written Description/Enablement

CLAIMS:
Amendments to the Claims:

This listing of claims will replace all prior versions, and listings, of claims in the application:

Listing of Claims:

Amdt date June 1, 2023 Reply to Office action of February 1, 2023

1 - 22. (canceled)221

23\. (New) A preparation method of an antibody-drug conjugate with a structure as shown in formula I:mAb-(L-D)n I wherein,
mAb represents a recombinant anti-CD20 monoclonal antibody, wherein the recombinant anti-CD20 monoclonal antibody is rituximab or a biosimilar thereof;
D represents a small molecule toxin, wherein the small molecule toxin is monomethyl auristatin-E (MMAE);
L is a linker connecting the antibody and the small molecule toxin, wherein the linker is maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl;n is an average number of the small molecule toxins conjugated to the antibody, and n is in a range of 4.2SVG {EMBED HERE} 0.100.080.5; and
"-" is a bond, and
wherein the structure of the antibody-drug conjugate is the following formula:mAbSVG {EMBED HERE} 1.3275.997SVG {EMBED HERE} 0.1430.347

wherein the preparation method comprises the steps of:
(1) performing a reduction reaction between the recombinant anti-CD20 monoclonal antibody and a reducing agent in a PB (phosphate buffer) reaction buffer (pH 7.6) at 25±10C for 90±10 minutes, thereby obtaining a reaction system comprising a reduced recombinant anti-CD20 monoclonal antibody, wherein the reducing agent is tris (2-carboxyethyl) phosphine, and a molar ratio of the recombinant anti-CD20 monoclonal antibody to the reducing agent is 1: 2.9 to 1: 3.1;
(2) adding a solution of the small molecule toxin in acetonitrile and water dropwise to the reaction system of step (1) and performing a coupling reaction at 4±0.5 0C for 60±10 minutes to obtain a coupling solution, wherein a volume ratio of acetonitrile to water is 1:1, and a molar ratio of the recombinant anti-CD20 monoclonal antibody in step (1) to the small molecule toxin is 1: 7.0 to 1: 8.0;
(3) adding into the reaction system obtained from step (2) a stopping solution of L-cysteine which is prepared by dissolving L-cysteine in a diethylenetriaminepentaacetic acid solution, to terminate the coupling reaction; and
(4) when the coupling reaction in step (3) is terminated, transferring the coupling solution to a tangential flow filtration (TFF) system for buffer replacement, thereby replacing the PB reaction buffer with a HT preparation buffer, and filtering the solution obtained with a 0.22 micrometer Rapid - Flow device, wherein the HT preparation buffer contains 3.18 g of L-histidine, 70 g of trehalose dihydrate, and 0.2 mL of Tween 80 per L, with pH adjusted to 6.5 using 0.5 mol/L hydrochloric acid, and then filtered through a 0.22 pm membrane.

24\. (New) The preparation method of claim 23, wherein n is in a range of 4.2 ± 0.3.

25\. (New) The preparation method of claim 23, wherein in step (1), the molar ratio of the recombinant anti-CD20 monoclonal antibody to the reducing agent is about 1:2.95-1:3.05.

26\. (New) The preparation method of claim 23, wherein in step (1), the molar ratio of the recombinant anti-CD20 monoclonal antibody to the reducing agent is about 1:2.99-1:3.01.

27\. (New) The preparation method of claim 23, wherein in step (1), the molar ratio of the recombinant anti-CD20 monoclonal antibody to the reducing agent is about 1:3.

28\. (New) The preparation method of claim 23, wherein in step (2), the molar ratio of the recombinant anti-CD20\_monoclonal antibody from step (1) to the small molecule toxin is about 1:7.2-1:7.7.

29\. (New) The preparation method of claim 23, wherein in step (2), the molar ratio of the recombinant anti-CD20\_monoclonal antibody from step (1) to the small molecule toxin is about 1:7.4-1:7.6.

30\. (New) The preparation method of claim 23, wherein in step (2), the molar ratio of the recombinant anti-CD20\_monoclonal antibody from step (1) to the small molecule toxin is about 1:7.5.

31\. (New) The preparation method of claim 23, wherein n is 4.2, and
in step (1), the reduction reaction between the recombinant anti-CD20 monoclonal antibody and the reducing agent is performed in the PB reaction buffer (pH

7.6) at 25 0C for 90 minutes, the molar ratio of the recombinant anti-CD20 monoclonal antibody to the reducing agent is 1:3; andin step (2), the solution of the small molecule toxin in acetonitrile and water is dropwise added to the reaction system of step (1) and the coupling reaction is performed at 4 0C for 60 minutes, and the molar ratio of the recombinant anti-CD20 monoclonal antibody in step (1) to the small molecule toxin is 1: 7.5.

32\. (New) An antibody drug conjugate prepared according to the preparation method of claim 23, wherein the average number of the small molecule toxins conjugated to the antibody is 4.2 ± 0.5.

33\. (New) The antibody drug conjugate of claim 32, wherein the average number of the small molecule toxins conjugated to the antibody is 4.2 ± 0.3.

34\. (New) An antibody drug conjugate pharmaceutical preparation prepared according to the preparation method of claim 23, wherein the average number of the small molecule toxins conjugated to the antibody is 4.2 ± 0.5.

35\. (New) The antibody drug conjugate pharmaceutical preparation prepared according to the preparation method of claim 34, wherein the average number of the small molecule toxins conjugated to the antibody is 4.2 ± 0.3.

OFFICE ACTION:
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 6/1/2023 has been entered.
The rejection under section 11(b) is withdrawn in view of Applicant’s amendments.
The rejection under section 103 is moot since the rejected claims have been canceled.  The rejection is newly applied to product-by-process claims 32-35:
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.
Claim(s) 32-35 are rejected under 35 U.S.C. 103 as being unpatentable over Jain et al., Pharm Res (2015) 32:3526–3540 (Jain);
in view of U.S. Publication No. 20050180972 based on an application by Wahl et al. (Wahl) and Chen et al., Determination of Drug-to-Antibody Ratio for Antibody-Drug Conjugates Purified from Serum, Agilent Technologies, pp. 1-9, 2016 (Agilent).
Jain teaches VAL-CIT-MMAE antibody conjugates:
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Jain teaches that these ADC’s with the recited drug-antibody-ratio (DAR) are known:
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Jain may fail to explicitly teach ADC’s with an anti-CD-20 antibody.  However, it is for that proposition that the examiner joins Wahl.  Specifically, Wahl teaches that conjugating mc-vc-PABC-MMAE to anti-CD20 antibodies, like rituximab, was common for cancer therapy:
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Wahl also discloses the recited excipients suitable for these ADC.s see paragraphs 247+.
In this way, those of ordinary skill could have applied anti-CD20 antibodies in the manner required and in a predictable fashion for the purposes of providing the recited ADC’s.  As outlined above, Jain teaches that the recited ADC’s with the recited drug-antibody-ratio (DAR) are common, such as mc-vc-PABC-MMAE.  Wahl is added for the proposition that anti-CD-20 antibodies are applicable to these ADC’s.  Specifically, Wahl teaches that the particular known technique of conjugating anti-CD-20 ADC’s with mc-vc-PABC-MMAE was recognized as part of the ordinary capabilities of one skilled in the art.  In this manner, those of ordinary skill would have recognized that applying the known technique to anti-CD-20 antibodies, like rituximab, would have yielded predictable results.  Accordingly, using anti-CD20 antibodies with mc-vc-PABC-MMAE would have been prima facie obvious.
With regard to the average number of the small molecule toxins conjugated to the antibody of 4.2 + 1, it is understood that the DAR in the table is an average DAR.  Indeed, those of ordinary skill would understand that preparation of the Rituximab vcMMAE in Wahl would produce a number of ADC’s with different DAR’s, including 4.
Nonetheless, there are a limited and finite number of DAR’s for a cysteine-bound antibody-drug conjugate (ADC), around 8. The prior art demonstrates that optimization of the DAR is a critical part of ADC development, since the DAR value affects the efficacy of the drug, as low drug loading reduces the potency, while high drug loading can negatively affect pharmacokinetics (PK)1 and toxicity. At the time the invention was made, easy, accurate and reproducible DAR calculation of ADC’s was within the purview of those of ordinary skill, see Agilent:
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In this manner, it would have been obvious to one having ordinary skill in the art at the time of applicant’s invention to have prepared ADC’s within the recited DAR with a reasonable expectation that the resulting ADC would be useful in treating cancer. In this connection, it is well-settled that cysteine-conjugated ADC’s with a DAR from 1-8 are well within the purview of those of ordinary skill (see above); and it would have been obvious to one of ordinary skill in the art at the time the invention was made to have chosen from this finite number of DAR options with a reasonable expectation of success of producing an ADC with a functional DAR.
Specifically, the DAR pf cysteine-bound ADC’s is optimizable.  It is well within the skill of the artisan to try any of the 1-8 DAR targets. As outlined above, a DAR value affects the efficacy of the drug, as low drug loading reduces the potency, while high drug loading can negatively affect pharmacokinetics (PK)1 and toxicity. Here, a skilled chemist at the time would simply make the known ADC’s of the known 8 DAR’s. Indeed, it would have been part and parcel to make the different DAR’s to find one that is pharmaceutically acceptable. See Agilent: (“The DAR is a critical quality attribute of an ADC that is optimized and closely monitored during ADC development, as it can affect efficacy and toxicity.”)  Therefore, the applied references provide ample reason to make the recited ADC’s with a DAR in the recited range.
With regard to any unpredictability associated with the DAR’s, the notion that unpredictability confers patentability in cases of DAR’s of known ADC’s should be disregarded since a rule of law equating unpredictability to patentability, applied in this case, would mean that any new ADC based on a different DAR would be separately patentable, simply because the formation and properties of each ADC must be verified through testing. This cannot be the proper standard since the expectation of success need only be reasonable, not absolute.
Here, the references provide the reasonable expectation of success. Namely, the references demonstrate the reasonable expectation of success since the references sufficiently characterize the instant ADC’s including the required heavy and light chains (i.e., Rituximab), conjugated to MMAE via a val/cit linker (see Jain and Wahl). Again, the expectation of success need only be reasonable, as it is here, and not absolute, (“obviousness does not require absolute predictability, only a reasonable expectation of success, i.e., a reasonable expectation of obtaining similar properties. See, e.g., In re O’Farrell, 853 F.2d 894, 903, 7 USPQ2d 1673, 1681 (Fed. Cir. 1988).”).
With regard to any alleged unexpected property possessed by those ADC’s with a DAR within the claimed range, it is error to assume that any superior property is unexpected, especially in the instant case, where the pharmacodynamic and pharmacokinetic properties of different DAR’s are not predictable. In this case, given the range of 8 possible DAR’s, one skilled in the art would expect different DAR’s to provide ADC’s having a range of properties, some of which would be superior, and some of which would be inferior.
Rather, Applicant has conducted a common optimization of the known DAR’s to produce the claimed ADC, which is routine. Specifically, Applicant engaged in routine, verification testing to optimize selection of one of several known and clearly suggested DAR’s to prepare a pharmaceutically-acceptable conjugate. In this regard, creating a “product or process that is more desirable, for example because it is stronger, cheaper, cleaner, faster, lighter, smaller, more durable, or more efficient . . . to enhance commercial opportunities . . . is universal—and even common-sensical.” see DyStar Textilfarben GmbH v. C.H. Patrick Co., 464 F.3d 1356 at 1368.
Finally, the claims recite product-by-process limitations.  Applicant has not demonstrated how these limitations distinguish the recited ADC, see MPEP 2113 (“[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process. In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985)”).
Therefore, the recited ADC’s with the recited DAR is obvious, within the meaning of section 103.
The rejected claims are product by process claims, the merits of which depend on the product, see MPEP 2113 (““[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985)”).
Claim(s) 23-31 are rejected under 35 U.S.C. 103 as being unpatentable over Jain et al., Pharm Res (2015) 32:3526–3540 (Jain) in view of (Wahl) and (Agilent); in further view of:
Agarwal et al., Bioconjugate Chem. 2015, 26, 2, 176–192 (Agarwal); and
Sun et al., Bioconjug Chem. 2005; 16: 1282- 1290 (Sun); and
Li Y et al., J Chromatogr A. 2015; 1393: 81- 88 (Li Y); and
Protein Concentration and Diafiltration by Tangential Flow Filtration, Millipore Techinical Brief, 2003, downloaded 7 June 2023 from http://wolfson.huji.ac.il/purification/PDF/dialysis/MILLIPORE_TFF.pdf (Millipore);
Teeters et al., Biotechnology and Bioengineering, Vol. 108, No. 6, June, 2011 (Teeters); and
U.S. Publication No. 20160045615 based on an application by Li et al. (Li); and
U.S. Publication No. 20170326251 based on an application by Evan et al. (Evans); and
Package Insert Herceptin (Trastuzumab) Genetech, Inc., 2000, downloaded 7 June 2023 from https://www.accessdata.fda.gov/drugsatfda_docs/label/2000/trasgen020900lb.htm (Herceptin).
The recited ADC is prima facie obvious, see section 103 rejection above citing Jain in view of Wahl and Agilent, which is incorporated herein by reference.  These references may fail to teach the required preparation steps.  However, it is for that proposition that the examiner joins the following references.
See Agarwal, teaching that the reduction steps were known:
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TCEP = tris(carboxyethyl)phosphine.
Once the conjugation is complete, cysteines, or N-acetyl-l-cysteine (NAC) can be used to quench any excess amount of thiol-reactive drug-linkers, often maleimide-containing drug-linkers, see for example, ADC preparation from Kozak.
For ADCs using reduced interchain cysteines for conjugation, the chemical steps include reduction of interchain disulfide bonds, conjugation, and quench of thiol-reactive drug-linkers before the final ultrafiltration and diafiltration (UF/DF) operation, see Sun and Li Y.
The TFF unit operation is a mainstay in concentration of proteins and buffer exchanges and has shown to be effective at removing solutes when the molar masses of the solutes are significantly lower than the protein.  Ultrafiltration (UF) is one of the most widely used forms of TFF and is used to separate proteins from buffer components for buffer exchange, desalting, or concentration, see Millipore.
For drug substance manufacturing, ultrafiltration/diafiltration (UF/DF) is typically the final process step performed to concentrate and exchange the purified drug substance to achieve the protein concentration, pH, and excipient concentrations necessary for product formulation, see Teeters.
See also, Li teaching ADC purification with TFF.
The prior art also provides sufficient reasons to exchange with the recited buffer in order to formulae the ADC, see paragraph 0386 of Evans.
See also Herceptin:
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The claims also cover relative amounts of reagents/reactants and solvents that may not be explicitly taught by the references.  However, these are results-effective parameters since they affect the efficiency of the process.  In this manner, their optimization by those of ordinary skill in the art is well within the ordinary skill of the purview of those of ordinary skill, and therefore, prima facie obvious.
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 23-35 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.
The instant conjugation step recites adding a solution of the small molecule toxin to the system.  However, in order to prepare the ADC of the formula in claim 23, conjugation is required between the linker/small molecule toxin.  The definition of the small molecule toxin in the specification does not include the linker portion.  Therefore, it is unclear how conjugation between the small molecule toxin and the reduced antibody can prepare the conjugate of claim 23, if the linker is not present.
Conclusion

APPLICANT REBUTTAL: REMARKS/ARGUMENTS
Claims 23-35 are currently pending in the present application. Claims 1-22 have been canceled, without prejudice and without disclaimer. Claims 23-35 are newly added. No new matter has been introduced.
In this amendment, Applicant has added various claims and canceled the others to expedite allowance of the application without prejudice or disclaimer. Applicant is not conceding patentability of the subject matter encompassed by the claims prior to this amendment over the art cited by the Examiner. As such, Applicant respectfully reserves the right to pursue these claims in one or more continuing applications, including claims capturing the subject matter encompassed by the claims prior to this amendment and additional claims. With this amendment, Applicant respectfully requests reconsideration and allowance of the pending claims.
Claim Amendments
Without conceding to any issues, in an effort to advance prosecution of the present application, Applicant has canceled Claims 1-22 and added claims 23-35 which are directed to a preparation method to better set forth the subject matter being claimed. Please refer to the new Claim 23, in which the steps and the features claimed are fully supported by paragraphs [0029]-[0043] as well as by Example 2 of the specification as originally filed. Further, new Claims 24-31 are directed to the additional technical features in the process of the preparation method depended from the new Claim 23 and supported by the specification as filed; and additionally, new Claims 32-35 directed to the ADCs and the pharmaceutical preparation obtained by the preparation method according to Claim 23. No new matter has been added.
Rejection of Claims Under 35 U.S.C.
%
Claims 1,5-7, 9, 11 -22 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre- AlA), 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.
Without conceding to any issues, in an effort to expedite allowance of the present application and to better set forth the subject matter being claimed, Applicant has canceled Claims 1-22 and added claims 23-35 which are directed to a preparation method. Accordingly, the rejection of the claims should now be moot. Applicant respectfully requests withdrawal of the rejections under 35 U.S.C. @ 112(b) or 35 U.S.C. 112 (pre-AIA), second paragraph.
Moreover, Applicant would like to further note that:
For "biosimilar" maintained in Claim 23, according to 42 U S C @ 262, term "biosimilar" or "biosimilarity", in reference to a biological product that is the subject of an application under subsection (k), means:
(A) that the biological product is highly similar to the reference product notwithstanding minor differences in clinically inactive components; and
(B) there are no clinically meaningful differences between the biological product and the reference product in terms of the safety, purity, and potency of the product.
In this case, based on 42 U S C @ 262:
"Rituximab" refers to a monoclonal antibody targeting CD20 developed by Roche, and has brand name "Rituxan". In the present application "Rituximab" is the reference product.
"Rituximab biosimilar" refers to a monoclonal antibody targeting CD20 developed by other companies, which has the same amino acid sequence and similar physicochemical properties, efficacy, pharmacokinetics, and safety to the reference product (Rituximab) developed by Roche.
In the field of biological product, due to different preparation processes, the TRS001 prepared by the Applicant should not be exactly the same as the rituximab prepared by Roche. In the present application, Example 1, the antibody (TRS001) developed by Applicant should be a Rituximab biosimilar.
Rej
ection of Claims Under 35 U.S.C.
§
Claim(s) 1,5-7, 9, 11 -22 are rejected under 35 U.S.C. § 103 as being unpatentable over Jain et al., Pharm Res (2015) 32:3526-3540 (hereinafter "Jain"); in view of U.S. Publication No. 20050180972 based on an application by Wahl et al. (hereinafter "Wahl") and Chen et al., Determination of Drug-to-Antibody Ratio for Antibody-Drug Conjugates Purified from Serum, Agilent Technologies, pp. 1-9, 2016 (hereinafter "Agilent").
Without conceding to any issues, in an effort to expedite allowance of the present application and to better set forth the subject matter being claimed, Applicant has canceled Claims 1-22 and added claims 23-35 which are directed to a preparation method. Applicant respectfully submits that Jain, Wahl, and Agilent, individually or in combination, should not teach, disclose, suggest, or provide for even the insight of the limitations and features recited by claims 23-35. Therefore, the present claims should be allowable over the references of record, and Applicant respectfully requests that the rejection under 35 U.S.C. § 103 be withdrawn.
In addition, Applicant notes Claims 23 - 31 should correspond to the subject matters claimed in CN application No. 201710087313.9 which have been granted as a patent right by the China National Intellectual Property Administration (CNIPA). Please refer to the enclosed Certificate of Invention just issued (Exhibit A), and the granted claims in that issued patent.
It should be noted that, during the examination on CN application No. 201710087313.9 and regarding inventiveness of the claims, U.S. Publication No.
20050180972 was also cited by the Examiner at CNIPA, as the primary or closest prior art. However, the CNIPA Examiner recognized the inventiveness of the claims directed toward the preparation method.
Here, as noted in a related cooperative program between the USPTO and participating foreign patent offices to expedite the allowance of utility patent applications that previously received favorable rulings (i.e., the Patent Prosecution Highway (PPH)), the USPTO notes that:
The Patent Prosecution Highway (PPH) speeds up the examination process for corresponding applications filed in participating intellectual property offices.
Under PPH, participating patent offices have agreed that when an applicant receives a ruling from a first patent office that at least one claim is allowable, the applicant may request fast track examination of corresponding claim(s) in a corresponding patent application that is pending in a second patent office. PPH leverages fast-track examination procedures already in place among participating patent offices to allow applicants to reach final disposition of a patent application more quickly and efficiently than standard examination processing.
As such, Applicant hopes the Examiner here may facilitate the examination of the allowability of the new claims in the USPTO based on at least the information discussed above and/or the work already done by the Examiner at the participating (CNIPA) patent office.
Concluding Remarks
In view of the foregoing amendments and remarks, Applicant earnestly solicits a timely issuance of a Notice of Allowance. If there are any remaining issues that can be addressed over the telephone, the Examiner is cordially invited to call Applicant's attorney at the number listed below.
Payment of any fee required to enter and process this amendment is provided. The Director is authorized to charge any underpayment of fees or credit any overpayment of fees to Deposit Account No. 03-1728.
Respectfully submitted, LEWIS ROCA ROTHGERBER CHRISTIE LLP

NEXT OFFICE ACTION: 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 .
The rejections under section 103 are maintained, below:
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.
Claim(s) 32-35 are rejected under 35 U.S.C. 103 as being unpatentable over Jain et al., Pharm Res (2015) 32:3526–3540 (Jain);
in view of U.S. Publication No. 20050180972 based on an application by Wahl et al. (Wahl) and Chen et al., Determination of Drug-to-Antibody Ratio for Antibody-Drug Conjugates Purified from Serum, Agilent Technologies, pp. 1-9, 2016 (Agilent).
Jain teaches VAL-CIT-MMAE antibody conjugates:
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Jain teaches that these ADC’s with the recited drug-antibody-ratio (DAR) are known:
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Jain may fail to explicitly teach ADC’s with an anti-CD-20 antibody.  However, it is for that proposition that the examiner joins Wahl.  Specifically, Wahl teaches that conjugating mc-vc-PABC-MMAE to anti-CD20 antibodies, like rituximab, was common for cancer therapy:
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Wahl also discloses the recited excipients suitable for these ADC.s see paragraphs 247+.
In this way, those of ordinary skill could have applied anti-CD20 antibodies in the manner required and in a predictable fashion for the purposes of providing the recited ADC’s.  As outlined above, Jain teaches that the recited ADC’s with the recited drug-antibody-ratio (DAR) are common, such as mc-vc-PABC-MMAE.  Wahl is added for the proposition that anti-CD-20 antibodies are applicable to these ADC’s.  Specifically, Wahl teaches that the particular known technique of conjugating anti-CD-20 ADC’s with mc-vc-PABC-MMAE was recognized as part of the ordinary capabilities of one skilled in the art.  In this manner, those of ordinary skill would have recognized that applying the known technique to anti-CD-20 antibodies, like rituximab, would have yielded predictable results.  Accordingly, using anti-CD20 antibodies with mc-vc-PABC-MMAE would have been prima facie obvious.
With regard to the average number of the small molecule toxins conjugated to the antibody of 4.2 + 1, it is understood that the DAR in the table is an average DAR.  Indeed, those of ordinary skill would understand that preparation of the Rituximab vcMMAE in Wahl would produce a number of ADC’s with different DAR’s, including 4.
Nonetheless, there are a limited and finite number of DAR’s for a cysteine-bound antibody-drug conjugate (ADC), around 8. The prior art demonstrates that optimization of the DAR is a critical part of ADC development, since the DAR value affects the efficacy of the drug, as low drug loading reduces the potency, while high drug loading can negatively affect pharmacokinetics (PK)1 and toxicity. At the time the invention was made, easy, accurate and reproducible DAR calculation of ADC’s was within the purview of those of ordinary skill, see Agilent:
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In this manner, it would have been obvious to one having ordinary skill in the art at the time of applicant’s invention to have prepared ADC’s within the recited DAR with a reasonable expectation that the resulting ADC would be useful in treating cancer. In this connection, it is well-settled that cysteine-conjugated ADC’s with a DAR from 1-8 are well within the purview of those of ordinary skill (see above); and it would have been obvious to one of ordinary skill in the art at the time the invention was made to have chosen from this finite number of DAR options with a reasonable expectation of success of producing an ADC with a functional DAR.
Specifically, the DAR pf cysteine-bound ADC’s is optimizable.  It is well within the skill of the artisan to try any of the 1-8 DAR targets. As outlined above, a DAR value affects the efficacy of the drug, as low drug loading reduces the potency, while high drug loading can negatively affect pharmacokinetics (PK)1 and toxicity. Here, a skilled chemist at the time would simply make the known ADC’s of the known 8 DAR’s. Indeed, it would have been part and parcel to make the different DAR’s to find one that is pharmaceutically acceptable. See Agilent: (“The DAR is a critical quality attribute of an ADC that is optimized and closely monitored during ADC development, as it can affect efficacy and toxicity.”)  Therefore, the applied references provide ample reason to make the recited ADC’s with a DAR in the recited range.
With regard to any unpredictability associated with the DAR’s, the notion that unpredictability confers patentability in cases of DAR’s of known ADC’s should be disregarded since a rule of law equating unpredictability to patentability, applied in this case, would mean that any new ADC based on a different DAR would be separately patentable, simply because the formation and properties of each ADC must be verified through testing. This cannot be the proper standard since the expectation of success need only be reasonable, not absolute.
Here, the references provide the reasonable expectation of success. Namely, the references demonstrate the reasonable expectation of success since the references sufficiently characterize the instant ADC’s including the required heavy and light chains (i.e., Rituximab), conjugated to MMAE via a val/cit linker (see Jain and Wahl). Again, the expectation of success need only be reasonable, as it is here, and not absolute, (“obviousness does not require absolute predictability, only a reasonable expectation of success, i.e., a reasonable expectation of obtaining similar properties. See, e.g., In re O’Farrell, 853 F.2d 894, 903, 7 USPQ2d 1673, 1681 (Fed. Cir. 1988).”).
With regard to any alleged unexpected property possessed by those ADC’s with a DAR within the claimed range, it is error to assume that any superior property is unexpected, especially in the instant case, where the pharmacodynamic and pharmacokinetic properties of different DAR’s are not predictable. In this case, given the range of 8 possible DAR’s, one skilled in the art would expect different DAR’s to provide ADC’s having a range of properties, some of which would be superior, and some of which would be inferior.
Rather, Applicant has conducted a common optimization of the known DAR’s to produce the claimed ADC, which is routine. Specifically, Applicant engaged in routine, verification testing to optimize selection of one of several known and clearly suggested DAR’s to prepare a pharmaceutically-acceptable conjugate. In this regard, creating a “product or process that is more desirable, for example because it is stronger, cheaper, cleaner, faster, lighter, smaller, more durable, or more efficient . . . to enhance commercial opportunities . . . is universal—and even common-sensical.” see DyStar Textilfarben GmbH v. C.H. Patrick Co., 464 F.3d 1356 at 1368.
Finally, the claims recite product-by-process limitations.  Applicant has not demonstrated how these limitations distinguish the recited ADC, see MPEP 2113 (“[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process. In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985)”).
Therefore, the recited ADC’s with the recited DAR is obvious, within the meaning of section 103.
The rejected claims are product by process claims, the merits of which depend on the product, see MPEP 2113 (““[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985)”).
Applicant argues that different DAR’s of MMAE-ADC’s were known in the art:
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However, Applicant even demonstrates that optimization of DAR was common, and accepted:
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Therefore, optimization of a known ADC, such as Rituximab vc-MMAE would have been well within the purview of those of ordinary skill, as exemplified by Applicant’s remarks, and as outlined in the rejection above.
Claim(s) 23-31 are rejected under 35 U.S.C. 103 as being unpatentable over Jain et al., Pharm Res (2015) 32:3526–3540 (Jain) in view of (Wahl) and (Agilent); in further view of:
Agarwal et al., Bioconjugate Chem. 2015, 26, 2, 176–192 (Agarwal); and
Sun et al., Bioconjug Chem. 2005; 16: 1282- 1290 (Sun); and
Li Y et al., J Chromatogr A. 2015; 1393: 81- 88 (Li Y); and
Protein Concentration and Diafiltration by Tangential Flow Filtration, Millipore Techinical Brief, 2003, downloaded 7 June 2023 from http://wolfson.huji.ac.il/purification/PDF/dialysis/MILLIPORE_TFF.pdf (Millipore);
Teeters et al., Biotechnology and Bioengineering, Vol. 108, No. 6, June, 2011 (Teeters); and
U.S. Publication No. 20160045615 based on an application by Li et al. (Li); and
U.S. Publication No. 20170326251 based on an application by Evan et al. (Evans); and
Package Insert Herceptin (Trastuzumab) Genetech, Inc., 2000, downloaded 7 June 2023 from https://www.accessdata.fda.gov/drugsatfda_docs/label/2000/trasgen020900lb.htm (Herceptin).
The recited ADC is prima facie obvious, see section 103 rejection above citing Jain in view of Wahl and Agilent, which is incorporated herein by reference.  These references may fail to teach the required preparation steps.  However, it is for that proposition that the examiner joins the following references.
See Agarwal, teaching that the reduction steps were known:
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TCEP = tris(carboxyethyl)phosphine.
Once the conjugation is complete, cysteines, or N-acetyl-l-cysteine (NAC) can be used to quench any excess amount of thiol-reactive drug-linkers, often maleimide-containing drug-linkers, see for example, ADC preparation from Kozak.
For ADCs using reduced interchain cysteines for conjugation, the chemical steps include reduction of interchain disulfide bonds, conjugation, and quench of thiol-reactive drug-linkers before the final ultrafiltration and diafiltration (UF/DF) operation, see Sun and Li Y.
The TFF unit operation is a mainstay in concentration of proteins and buffer exchanges and has shown to be effective at removing solutes when the molar masses of the solutes are significantly lower than the protein.  Ultrafiltration (UF) is one of the most widely used forms of TFF and is used to separate proteins from buffer components for buffer exchange, desalting, or concentration, see Millipore.
For drug substance manufacturing, ultrafiltration/diafiltration (UF/DF) is typically the final process step performed to concentrate and exchange the purified drug substance to achieve the protein concentration, pH, and excipient concentrations necessary for product formulation, see Teeters.
See also, Li teaching ADC purification with TFF.
The prior art also provides sufficient reasons to exchange with the recited buffer in order to formulae the ADC, see paragraph 0386 of Evans.
See also Herceptin:
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The claims also cover relative amounts of reagents/reactants and solvents that may not be explicitly taught by the references.  However, these are results-effective parameters since they affect the efficiency of the process.  In this manner, their optimization by those of ordinary skill in the art is well within the ordinary skill of the purview of those of ordinary skill, and therefore, prima facie obvious.
Applicant has not distinguished the residual rate of PB from that of the references.
Moreover, the references demonstrate that vc-MMAE have known to have a DAR of 4, see Jain:
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The references demonstrate that optimization of DAR was known, and routine.
Applicant submits references that show the recited DAR was common:
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Applicant has not shown why those of ordinary skill would not have reason to optimize DAR’ of the instant ADC’s.  In this regard, Applicant has not shown why those of ordinary skill would not expect a reasonable expectation of therapeutic success of the instant ADC’s with a DAR of 4.
Therefore, the rejection is maintained.
The rejection under section 112(b) is withdrawn in favor of the following new grounds of rejection, which are necessitated by Applicant’s amendments.
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 23-35 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.
The claims have been amended to recite that vc-MMAE is used as a conjugation reagent.  However, the formula in claim 23 also contains a maleimidocaproyl component not structurally-accounted for by vc-MMAE.
Claims 32-35 recite components of the instant ADC’s.  Some of the components are outside the recited DAR, e.g., 2, 6, 8, 0.    It is unclear how these components relate to the recited ADC’s. Moreover, if these are “components” of the instant ADC’s, it is unclear if Applicant is claiming an ADC or a composition of different ADC’s, some of which are outside the recited DAR.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action.  Accordingly, THIS ACTION IS MADE FINAL.  See MPEP § 706.07(a).  Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action.  In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action.  In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
Conclusion

CITED REFERENCE SUMMARIES: Ref US20160045615A1: Claims:
A method for removing benzodiazepine drug-related impurities from a mixture comprising benzodizepine ADCs and benzodiazepine drug-related impurities comprising subjecting the mixture to tangential flow filtration while maintaining a concentration of at least about 1% w/v cylodextrin in the mixture.
The method of claim 1 wherein the cyclodextrin is present in the mixture at the start of tangential flow filtration.
The method of claim 1 wherein the cyclodextrin is added to the mixture prior to any substantial removal of benzodiazepine drug-related impurities and cyclodextrin is thereafter maintained at a concentration of at least about 1% w/v in the mixture.
The method of claim 1 wherein the tangential flow filtration is constant volume diafiltration.
The method of claim 1 wherein the tangential flow filtration device comprises a pump, a filtration holder having an inlet, a filtrate outlet, a retentate outlet, an ultrafiltration membrane having a pore size of about 50 Kd or smaller that separates the filtration holder into an upstream compartment and a downstream compartment such that all filtrate must enter the inlet and pass through the ultrafiltration membrane before exiting the filtration holder through the filtrate outlet, a sample reservoir for holding the conjugation reaction mixture, and a buffer reservoir in fluid communication with the sample reservoir and wherein the buffer in the buffer reservoir comprises at least about 1% w/v cylodextrin, at least about 2% w/v cylodextrin, or at least about 3% w/v cylodextrin.
The method of claim 7 wherein the buffer replaces the filtration volume at the same rate as the filtrate flow such that the volume in the tangential flow filtration device remains constant.
The method of claim 1 wherein the filtration is discontinuous diafiltration.
The method of claim 1 further comprising the steps of (i) contacting an antibody with a benzodizepine drug-linker under conditions sufficient to form a conjugation reaction mixture comprising benzodiazepine ADCs, and (ii) contacting the reaction mixture with a quenching agent to form a quenched conjugation reaction mixture, wherein said mixture subjected to tangential flow filtration is a quenched conjugation reaction mixture.
The method of claim 1 wherein the benzodiazepine drug-related impurities are quenched benzodiazepine drug-linkers.
The method of claim 11 wherein the quenched benzodiazepine drug-linkers have a SlogP value of no more than 7.50 or no more than 6.5.
The method of claim 1 wherein the benzodiazepine drug-related impurities are reduced to a level of about 1 Î¼M or less, 0.5 Î¼M or less, 0.1 Î¼M or less, or 0.05 Î¼M or less
The method of claim 1 wherein the cyclodextrin is a chemically modified beta cyclodextrin selecting from the group consisting of hydroxypropyl beta cyclodextrin and sulfobutylether beta cyclodextrin.
The method of claim 1 wherein the benzodiazepine ADC is a monoclonal antibody conjugated to a pyrrolobenzodiazepine dimer, an indolinobenzodiazepine dimer or an oxazolidinobenzodiazepine dimer.
The method of claim 17 wherein the benzodiazepine ADC is a monoclonal antibody conjugated to a pyrrolobenzodiazepine dimer and having the following formula:
or a salt thereof, wherein Ab is a monoclonal antibody and p represents the average number of drug-linker molecules per antibody in the mixture and is about 2.
The method of claim 19 wherein the benzodiazepine drug-related impurity is a quenched drug-linker wherein the drug-linker prior to quenching has the formula:
or a salt thereof.
- 23 . (canceled)
A pharmaceutical formulation comprising: a benzodiazepine ADC; and cyclodextrin at a concentration of from about 3% w/v to about 30% w/v.
a benzodiazepine ADC; and
cyclodextrin at a concentration of from about 3% w/v to about 30% w/v.
The pharmaceutical formulation of claim 24 wherein the formulation further comprises at least one buffering agent; wherein the formulation is in an aqueous solution and the concentration of that at least one buffering agent is effective to maintain a physiologically suitable pH.
The pharmaceutical formulation of claim 24 , further comprising a lyoprotectant.
- 32 . (canceled)
The pharmaceutical formulation of claim 24 wherein the formulation has a pH of about 6.0 to about 8.0.
The pharmaceutical formulation of claim 25 wherein the at least one buffering agent is selected from the group consisting of Tris, acetate, histidine, citrate, phosphate, and succinate.
The pharmaceutical formulation of claim 24 wherein the benzodiazepine ADC is present at a concentration of from about 0.5 mg/ml, 1 mg/ml or 2 mg/ml to about 10 mg/ml or about 30 mg/ml.
- 41 . (canceled)
The pharmaceutical formulation of claim 24 wherein the cyclodextrin is a chemically modified beta cyclodextrin selecting from the group consisting of hydroxypropyl beta cyclodextrin and sulfobutylether beta cyclodextrin.
The pharmaceutical formulation of claim 24 wherein the benzodiazepine ADC is a monoclonal antibody conjugated to a pyrrolobenzodiazepine dimer, an indolinobenzodiazepine dimer or a oxazolidinobenzodiazepine dimer.
The pharmaceutical formulation of claim 45 wherein the benzodiazepine ADC is a monoclonal antibody conjugated to a pyrrolobenzodiazepine dimer and the benzodiazepine ADC is as follows:
or a pharmaceutically acceptable salt thereof; wherein Ab is a monoclonal antibody and p represents the average number of drug-linker molecules per antibody in the formulation and is about 2.
The pharmaceutical formulation of claim 24 wherein the antibody component of the ADC is an antibody that specifically binds to an extracellular domain of human CD33 or human CD70.
- 63 . (canceled)
The pharmaceutical formulation of claim 24 having improved stability as measured by a reduction in chemical degradation of the benzodiazepine drug linker present in the formulation as compared to a benzodiazepine drug linker having 2% w/v cyclodextrin or less.
The pharmaceutical formulation of claim 24 having 0.1 Î¼M or less benzodiazepine drug-related impurities in the formulation.
Ref US20170326251A1: Claims:
A method of synthesising synthesizing a biomolecule-drug-conjugate, the method comprising: a) optionally contacting a biomolecule with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide a chemically modified, enzymatically modified, or activated biomolecule; b) (i) when step (a) is carried out, contacting the chemically modified, enzymatically modified, or activated biomolecule of step (a) with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the chemically modified, enzymatically modified, or activated biomolecule and therefore provide an immobilised chemically modified, enzymatically modified, or activated biomolecule; or (ii) when step (a) is not carried out, contacting a biomolecule with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the biomolecule and therefore provide an immobilised biomolecule; c) optionally contacting the immobilised chemically modified, enzymatically modified, or activated biomolecule of step (b) (i) or the immobilised biomolecule of step (b) (ii) with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide an immobilised chemically modified, enzymatically modified, or and/or activated biomolecule; d) optionally washing the immobilised chemically modified, enzymatically modified, or activated biomolecule of step (b) (i); the immobilised biomolecule of step (b) (ii); or the immobilised chemically modified, enzymatically modified, or activated, immobilised biomolecule of step (c) with buffer to remove superfluous or unreacted chemical modification agent, enzymatic modification agent, or superfluous or unreacted activating agent, e) optionally repeating step (c) and step (d); f) optionally contacting a drug component with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide a chemically modified, enzymatically modified, or activated drug component; g) (i) when step (f) is carried out, contacting the immobilised biomolecule or the immobilised chemically modified, enzymatically modified, or and/or activated biomolecule with the chemically modified, enzymatically modified, or activated drug component of step (f) to form an immobilised biomolecule-drug-conjugate; or (ii) when step (f) is not carried out contacting the immobilised biomolecule or the immobilised chemically modified, enzymatically modified, or and/or activated biomolecule with a drug component to form an immobilised biomolecule-drug-conjugate; h) optionally washing the immobilised biomolecule-drug-conjugate of step (g) with buffer to remove superfluous or unreacted reagents, to provide a purified immobilised biomolecule-drug conjugate; i) releasing the purified biomolecule-drug-conjugate from the capture resin;
a) optionally contacting a biomolecule with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide a chemically modified, enzymatically modified, or activated biomolecule;
b) (i) when step (a) is carried out, contacting the chemically modified, enzymatically modified, or activated biomolecule of step (a) with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the chemically modified, enzymatically modified, or activated biomolecule and therefore provide an immobilised chemically modified, enzymatically modified, or activated biomolecule; or (ii) when step (a) is not carried out, contacting a biomolecule with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the biomolecule and therefore provide an immobilised biomolecule;
(i) when step (a) is carried out, contacting the chemically modified, enzymatically modified, or activated biomolecule of step (a) with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the chemically modified, enzymatically modified, or activated biomolecule and therefore provide an immobilised chemically modified, enzymatically modified, or activated biomolecule; or
(ii) when step (a) is not carried out, contacting a biomolecule with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the biomolecule and therefore provide an immobilised biomolecule;
c) optionally contacting the immobilised chemically modified, enzymatically modified, or activated biomolecule of step (b) (i) or the immobilised biomolecule of step (b) (ii) with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide an immobilised chemically modified, enzymatically modified, or and/or activated biomolecule;
d) optionally washing the immobilised chemically modified, enzymatically modified, or activated biomolecule of step (b) (i); the immobilised biomolecule of step (b) (ii); or the immobilised chemically modified, enzymatically modified, or activated, immobilised biomolecule of step (c) with buffer to remove superfluous or unreacted chemical modification agent, enzymatic modification agent, or superfluous or unreacted activating agent,
e) optionally repeating step (c) and step (d);
f) optionally contacting a drug component with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide a chemically modified, enzymatically modified, or activated drug component;
g) (i) when step (f) is carried out, contacting the immobilised biomolecule or the immobilised chemically modified, enzymatically modified, or and/or activated biomolecule with the chemically modified, enzymatically modified, or activated drug component of step (f) to form an immobilised biomolecule-drug-conjugate; or (ii) when step (f) is not carried out contacting the immobilised biomolecule or the immobilised chemically modified, enzymatically modified, or and/or activated biomolecule with a drug component to form an immobilised biomolecule-drug-conjugate;
(i) when step (f) is carried out, contacting the immobilised biomolecule or the immobilised chemically modified, enzymatically modified, or and/or activated biomolecule with the chemically modified, enzymatically modified, or activated drug component of step (f) to form an immobilised biomolecule-drug-conjugate; or
(ii) when step (f) is not carried out contacting the immobilised biomolecule or the immobilised chemically modified, enzymatically modified, or and/or activated biomolecule with a drug component to form an immobilised biomolecule-drug-conjugate;
h) optionally washing the immobilised biomolecule-drug-conjugate of step (g) with buffer to remove superfluous or unreacted reagents, to provide a purified immobilised biomolecule-drug conjugate;
i) releasing the purified biomolecule-drug-conjugate from the capture resin;
wherein the biomolecule is selected from the group consisting of an antibody, a modified antibody, and an antibody fragment.
The method of claim 1 , wherein step (a) is carried out.
The method of claim 3 , wherein step (a) involves reducing the biomolecule.
The method of claim 3 , wherein step (a) involves reacting the biomolecule with a crosslinker moiety, optionally wherein the crosslinker moiety is an amine-to-sulfhydryl crosslinker.
The method of claim 5 , wherein the crosslinker moiety is succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC).
The method of claim 1 any preceding claim, wherein step (b) involves incubation with the capture resin, optionally wherein the incubation is carried out at temperature of from about 5Â° C. to about 50Â° C. or and/or optionally wherein the incubation is for a period of time of from about 10 minutes to about 18 hours.
The method of claim 1 , wherein step (c) is carried out.
The method of claim 9 , wherein step (c) involves reducing the biomolecule.
The method of claim 9 , wherein step (c) involves reacting the biomolecule with a crosslinker moiety, optionally wherein the crosslinker moiety is an amine-to-sulfhydryl crosslinker.
The method of claim 11 , wherein the crosslinker moiety is succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC).
The method of claim 1 , wherein step (d) is omitted.
The method of claim 1 , wherein step (d) is carried out, optionally wherein the washing involves rinsing with a buffer, further optionally wherein the buffer is phosphate buffered saline (PBS).
The method of claim 1 , wherein step (f) is carried out.
The method of claim 16 , wherein the step of contacting the drug component with a chemical modification agent, an enzymatic modification agent, or an activating agent to provide a modified or activated drug component involves reacting the drug component with a crosslinker moiety, optionally wherein the crosslinker moiety is an amine-to-sulfhydryl crosslinker.
The method of claim 17 , wherein the crosslinker moiety is succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC).
The method of claim 1 , wherein step (g) involves simultaneously (1) carrying out the chemical modification, enzymatic modification or activation of the drug component and (2) contacting the immobilised biomolecule or the chemically modified, enzymatically modified, or and/or activated, immobilised biomolecule.
- 21 . (canceled)
The method of claim 1 , wherein step (h) is carried out, optionally wherein the washing involves rinsing with a buffer, further optionally wherein the buffer is phosphate buffered saline (PBS).
The method of claim 1 , wherein step (i) involves a) exposing the support-biomolecule compound to a release agent; or b) altering the pH to break the support-biomolecule bond.
The method of claim 1 , wherein the capture resin is selected from the group consisting of Fabsorbentâ¢ F1P HF resin, Mabsorbentâ¢ A1P resin, and Mabsorbenâ¢ A2P resin.
A method of synthesizing a chemically modified, an enzymatically modified, or an activated, immobilised biomolecule, the method comprising: (a) optionally contacting a biomolecule with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide a chemically modified, enzymatically modified, or activated biomolecule; (b) (i) when step (a) is carried out, contacting the chemically modified, enzymatically modified, or activated biomolecule of step (a) with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G, Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the chemically modified, enzymatically modified, or activated biomolecule and therefore provide an immobilised chemically modified, enzymatically modified or activated biomolecule; or (ii) when step (a) is not carried out, contacting a biomolecule with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G, and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the biomolecule and therefore provide an immobilised biomolecule; (c) contacting the immobilised chemically modified, enzymatically modified, or activated biomolecule of step (b) (i); or the immobilised biomolecule of step (b) (ii) with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide an immobilised chemically modified, enzymatically modified, or activated biomolecule; wherein the biomolecule is selected from the group consisting of an antibody, a modified antibody, and an antibody fragment.
(a) optionally contacting a biomolecule with an agent selected from the group consisting of a chemical modification agent, an enzymatic modification agent, and an activating agent to provide a chemically modified, enzymatically modified, or activated biomolecule;
(b) (i) when step (a) is carried out, contacting the chemically modified, enzymatically modified, or activated biomolecule of step (a) with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G, Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the chemically modified, enzymatically modified, or activated biomolecule and therefore provide an immobilised chemically modified, enzymatically modified or activated biomolecule; or (ii) when step (a) is not carried out, contacting a biomolecule with a capture resin comprising a non-peptide based capture moiety selected from the group consisting of Protein A, Protein G, and Protein L mimetic biomolecule capture moiety under conditions suitable to immobilise the biomolecule and therefore provide an immobilised biomolecule;
(i) when step (a) is carried out, contacting the chemically modified, enzymatically mo
[Truncated to input limit]