Claims for Patent: 10,815,309

Summary for Patent: 10,815,309

Title:	Methods for preparing antibody-drug conjugates
Abstract:	This invention describes a method of conjugating a cell binding agent such as an antibody with an effector group (e.g., a cytotoxic agent) or a reporter group (e.g., a radionuclide), whereby the reporter or effector group is first reacted with a bifunctional linker and the mixture is then used without purification for the conjugation reaction with the cell binding agent. The method described in this invention is advantageous for preparation of stably-linked conjugates of cell binding agents, such as antibodies with effector or reporter groups. This conjugation method provides in high yields conjugates of high purity and homogeneity that are without inter-chain cross-linking and inactivated linker residues.
Inventor(s):	Kellogg; Brenda A. (Medford, MA), Singh; Rajeeva (Framingham, MA), Chari; Ravi V. (Newton, MA)
Assignee:	IMMUNOGEN, INC. (Waltham, MA)
Application Number:	16/265,249
Patent Claims:	1. A process for preparing a purified conjugate in a solution, wherein the conjugate comprises a maytansinoid comprising a thiol group linked to a cell binding agent, the process comprising the steps of: (a) contacting a maytansinoid comprising a thiol group with a bifunctional linker reagent comprising a maleimido-based moiety and an N-hydroxysuccinimide ester group to covalently attach the linker to the maytansinoid and thereby prepare an unpurified first mixture comprising the maytansinoid having linkers bound thereto, (b) conjugating a cell binding agent to the maytansinoid having linkers bound thereto by reacting the unpurified first mixture with the cell binding agent to prepare a second mixture, and (c) subjecting the second mixture to tangential flow filtration, dialysis, gel filtration, adsorptive chromatography, selective precipitation or a combination thereof to thereby prepare the purified conjugate wherein step (b) is carried out in a solution at a pH from about 4 to about 9. 2. The process of claim 1, wherein the pH of the solution in step (b) is from about 5 to about 8.7. 3. The process of claim 1, wherein the pH of the solution in step (b) is from about 6.5 to about 8.5. 4. The process of claim 1, wherein the second mixture in step (b) is substantially free of undesired cross-linked, hydrolyzed species formed due to intramolecular or inter-molecular reactions. 5. The process of claim 1, wherein the maytansinoid is DM1. 6. The process of claim 1, wherein the maytansinoid is DM4. 7. The process of claim 1, wherein the cell binding agent is an interferon, interleukin 2 (IL-2), interleukin 3 (IL-3), interleukin 4 (IL-4), interleukin 6 (IL-6), insulin, EGF, TGF-a, FGF, G-CSF, VEGF, MCSF, GM-CSF, transferrin, or an antibody. 8. The process of claim 7, wherein the cell binding agent is an antibody. 9. The process of claim 8, wherein the antibody is a monoclonal antibody. 10. The process of claim 8, wherein the antibody is a human or a humanized monoclonal antibody. 11. The process of claim 8, wherein the antibody is MY9, anti-B4, C242, or an antibody that binds to an antigen selected from EpCAM, CD2, CD3, CD4, CD5, CD6, CD11, CD19, CD20, CD22, CD26, CD30, CD33, CD37, CD38, CD40, CD44, CD56, CD79, CD105, CD138, EphA receptors, EphB receptors, EGFR, EGFRvIII, HER2, HER3, mesothelin, cripto, alphavbeta3, alphavbeta5, and alphavbeta6 integrin. 12. The process of claim 10, wherein the human or the humanized antibody is huMy9-6, huB4, huC242, huN901, DS6, CNTO 95, B--B4, trastuzumab, pertuzumab, bivatuzumab, sibrotuzumab, rituximab, or a human or humanized antibody that binds to an antigen selected from EphA2 receptor, CD38, and IGF-IR. 13. The process of claim 8, wherein the antibody is a fragment of an antibody. 14. The process of claim 13, wherein the fragment of an antibody is a scFv, Fab, Fab' or F(ab').sub.2. 15. The process of claim 1, wherein an excess of maytansinoid relative to the bifunctional linker reagent is used. 16. The process of claim 15, wherein the process further comprises the step of quenching the excess maytansinoid in the unpurified first mixture with a quenching reagent between steps (a) and (b). 17. The process of claim 16, wherein the quenching reagent is selected from 4-maleimidobutyric acid, 3-maleimidopropionic acid, N-ethylmaleimide, iodoacetamide, and iodoacetamidopropionic acid. 18. The process of claim 1, wherein the bifunctional linker reagent comprising a maleimido-based moiety and an N-hydroxysuccinimide ester group is selected from N-succinimidyl 4-(maleimidomethyl)cyclohexanecarboxylate (SMCC), N-succinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxy-(6-amidocaproa- te), .kappa.-maleimidoundecanoic acid N-succinimidyl ester (KMUA), .gamma.-maleimidobutyric acid N-succinimidyl ester (GMBS), .epsilon.-maleimidocaproic acid N-hydroxysuccinimide ester (EMCS), m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS), N-(.alpha.-maleimidoacetoxy)-succinimide ester (AMAS), succinimidyl-6-(.beta.-maleimidopropionamido)hexanoate (SMPH), and N-succinimidyl 4-(p-maleimidophenyl)-butyrate (SMPB), and N-(p-maleimidophenyl)isocyanate (PMPI). 19. The process of claim 18, wherein the bifunctional linker reagent comprising a maleimido-based moiety and an N-hydroxysuccinimide ester group is .gamma.-maleimidobutyric acid N-succinimidyl ester (GMBS).

Details for Patent 10,815,309

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Genentech, Inc.	RITUXAN	rituximab	Injection	103705	November 26, 1997	10,815,309	2039-02-01
Genentech, Inc.	HERCEPTIN	trastuzumab	For Injection	103792	September 25, 1998	10,815,309	2039-02-01
Genentech, Inc.	HERCEPTIN	trastuzumab	For Injection	103792	February 10, 2017	10,815,309	2039-02-01
Genentech, Inc.	PERJETA	pertuzumab	Injection	125409	June 08, 2012	10,815,309	2039-02-01