Pfizer enters phase 3 with a CDK4 inhibitor

Pfizer continues to advance its aim of developing a portfolio of next-generation therapies for treating ER-positive breast cancer. Among these assets is PF-07220060, a selective CDK4 inhibitor designed to improve on existing CDK4/6 inhibitors by maximising CDK4 coverage, and the first phase 3 trial of PF-07220060 has just been posted on clinicaltrials.gov and is due to start enrolling patients in December. Most HR-positive breast cancers express low CDK6, while CDK4 is likely to be a major cell cycle driver. Pfizer claims that the neutropenia seen with standard CDK4/6 inhibitors is mostly driven by the inhibition of CDK6, translating into an obstacle to complete CDK4 inhibition. The phase 3 trial will evaluate a combination of PF-07220060 and Faslodex versus investigator's choice of Faslodex alone or everolimus plus exemestane in advanced or metastatic HR-positive/HER2-negative breast cancer patients progressed on prior CDK4/6 inhibitor-based therapy. The dual primary endpoints are PFS and ORR, and according to clinicaltrials.gov data readout could be available as early as November 2025.

Other next-generation ER+ breast cancer therapies from Pfizer

Source: OncologyPipeline & company updates.