Pfizer Inc. (NYSE:PFE) on Tuesday announced topline results from the Phase 2 FOURLIGHT-1 study in pretreated metastatic breast cancer patients.

The trial, which included 264 patients with HR-positive, HER2-negative advanced or metastatic breast cancer, evaluated atirmociclib in combination with fulvestrant versus fulvestrant or everolimus plus exemestane for second-line treatment.

The study met its primary endpoint, showing a significant improvement in progression-free survival (PFS), consistent across all prespecified subgroups. Over 90% of patients started atirmociclib within three months of their last CDK4/6 inhibitor treatment.

Overall Survival Data Still Maturing

Overall survival (OS) data remains immature, with about 20% of participants experiencing an event. Atirmociclib was well tolerated, with 6.4% of patients discontinuing due to treatment-related adverse events.

The safety profile was consistent with prior studies, with no new safety signals. Detailed results will be presented at a future medical meeting.

A Phase 3 registrational study is evaluating atirmociclib in the first-line metastatic setting, and researchers will share results from a Phase 2 neoadjuvant study in early breast cancer at a future medical meeting.

Pfizer Complete FDA Approval For Mutated Colorectal Cancer

In February, the FDA granted full approval to Braftovi (encorafenib) in combination with cetuximab and fluorouracil-based chemotherapy for adult patients with metastatic colorectal cancer (mCRC) harboring a BRAF V600E mutation.

In December 2024, the FDA granted accelerated approval to Braftovi in combination with cetuximab and mFOLFOX6 for BRAF V600E-mutant mCRC.

The approval is based on results from the Phase 3 BREAKWATER trial, which demonstrated significant improvements in progression-free survival and overall survival.

PFE Stock Price Activity: Pfizer shares were up 1.35% at $26.97 at the time of publication on Tuesday, according to Benzinga Pro data.

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