Partners Arvinas, Inc. (NASDAQ: ARVN) and Pfizer Inc. (NYSE: PFE) have jointly presented preliminary data from the ongoing Phase Ib portion of the TACTIVE-U sub-study at the 2024 San Antonio Breast Cancer Symposium (SABCS) in San Antonio, Texas. The study assesses vepdegestrant in combination with Verzenios (abemaciclib) in patients with locally advanced or metastatic estrogen receptor positive (ER+)/human epidermal growth factor receptor 2 negative (HER2-) breast cancer.
Preliminary Results and Safety Profile
Preliminary results from 16 patients demonstrated a tolerable safety profile for the combination of abemaciclib 150 mg twice daily (BID) with the recommended Phase III monotherapy dose of vepdegestrant (200mg once daily; QD). An encouraging clinical benefit rate of 62.5% was observed among patients with both mutant ESR1 and wild-type ESR1 disease who had all been previously treated with a CDK4/6 inhibitor. The overall response rate (ORR) was 26.7%. Pharmacokinetic data showed no significant drug-drug interaction between vepdegestrant and abemaciclib, and no clinically meaningful effect on abemaciclib exposure was observed. The tolerability and safety of the combination were consistent with both the known properties of abemaciclib and observed data in other clinical trials for vepdegestrant.
Vepdegestrant’s Mechanism and Global Partnership
Vepdegestrant, a PROteolysis TArgeting Chimera (PROTAC) estrogen receptor (ER) degrader, is co-developed and commercialized by the two US companies via a global partnership agreement established in July 2021. The drug was granted a Fast Track designation by the U.S. Food and Drug Administration (FDA) as a monotherapy in the treatment of adults with ER+/HER2- locally advanced or metastatic breast cancer previously treated with endocrine-based therapy.-Fineline Info & Tech
