title: Optimization of Tubulysin Antibody-Drug Conjugates: A Case Study in Addressing ADC Metabolism.
abstract: As part of our efforts to develop new classes of tubulin inhibitor payloads for antibody-drug conjugate (ADC) programs, we developed a tubulysin ADC that demonstrated excellent in vitro activity but suffered from rapid metabolism of a critical acetate ester. A two-pronged strategy was employed to address this metabolism. First, the hydrolytically labile ester was replaced by a carbamate functional group resulting in a more stable ADC that retained potency in cellular assays. Second, site-specific conjugation was employed in order to design ADCs with reduced metabolic liabilities. Using the later approach, we were able to identify a conjugate at the 334C position of the heavy chain that resulted in an ADC with considerably reduced metabolism and improved efficacy. The examples discussed herein provide one of the clearest demonstrations to-date that site of conjugation can play a critical role in addressing metabolic and PK liabilities of an ADC. Moreover, a clear correlation was identified between the hydrophobicity of an ADC and its susceptibility to metabolic enzymes. Importantly, this study demonstrates that traditional medicinal chemistry strategies can be effectively applied to ADC programs.
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: L Nathan
authors.initials: LN
authors.lastname: Tumey
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Carolyn A
authors.initials: CA
authors.lastname: Leverett
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Beth
authors.initials: B
authors.lastname: Vetelino
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Fengping
authors.initials: F
authors.lastname: Li
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Brian
authors.initials: B
authors.lastname: Rago
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Han
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Frank
authors.initials: F
authors.lastname: Loganzo
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Musto
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Guoyun
authors.initials: G
authors.lastname: Bai
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Sai Chetan K
authors.initials: SC
authors.lastname: Sukuru
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Edmund I
authors.initials: EI
authors.lastname: Graziani
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Sujiet
authors.initials: S
authors.lastname: Puthenveetil
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Casavant
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Anokha
authors.initials: A
authors.lastname: Ratnayake
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Marquette
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Sarah
authors.initials: S
authors.lastname: Hudson
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Venkata Ramana
authors.initials: VR
authors.lastname: Doppalapudi
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Stock
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Lioudmila
authors.initials: L
authors.lastname: Tchistiakova
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Bessire
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Tracey
authors.initials: T
authors.lastname: Clark
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Judy
authors.initials: J
authors.lastname: Lucas
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Christine
authors.initials: C
authors.lastname: Hosselet
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: O'Donnell
authors.affiliation: Pfizer, Inc. , 445 Eastern Point Road, Groton, Connecticut 06379, United States.
authors.forename: Chakrapani
authors.initials: C
authors.lastname: Subramanyam
keywords: Antibody−drug conjugate (ADC); hydrophobic interaction chromatograph (HIC); plasma stability; tubulysin