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
| Asset | MoA | Current development status | Setting/select combinations |
|---|---|---|---|
| Vepdegestrant (Arvinas collaboration) | ER-degrading PROTAC | Phase 3 Veritac-2 | 2L monotherapy, patients after prior CDK4/6i |
| Phase 3 Veritac-3 | 1L combination with Ibrance | ||
| PF-07104091 | CDK2 inhibitor | FIH Phase 1/2 trial | Combination with Ibrance was discontinued |
| Phase 1b/2 combination trial | Multiple settings in combination with CDK4 inhibitor (PF-07220060) | ||
| PF-07248144 | KAT6 inhibitor | FIH Phase 1 trial | Combinations with Ibrance and CDK4 inhibitor (PF-07220060) |
Source: OncologyPipeline & company updates.
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