PF-06380101 is an auristatin microtubule inhibitor and is a cytotoxic Dolastatin 10 analogue. When compared to other synthetic auristatin analogues that are used in the preparation of ADCs, PF-06380101 displays excellent potencies in tumor cell proliferation assays and differential ADME properties.

PF-06380101 is considered likely to pose a low risk of causing pharmacokinetic drug interactions for drugs primarily cleared via metabolism by CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and/or CYP3A4/5 enzymes. It has been found to distribute more in human plasma than in whole blood and is identified as a P-glycoprotein (P-gp) substrate. In pharmacokinetic evaluations, PF-06380101 demonstrated a mean systemic clearance (Cl) rate of 70 mL/min/kg and a volume of distribution (Vss) of 14.70 L/kg following an intravenous (IV) dose of 20a at 20 μg/kg in Wistar Han rats. This resulted in a terminal elimination half-life (t1/2) of approximately 6 hours. The potential of new auristatin analogues, particularly 20a (PF-06380101), as antibody-drug conjugate (ADC) payloads, will be elaborated in forthcoming reports.