Pfizer Inc. (PFE.US) achieves primary endpoint with potential "first-in-class" small molecule combination therapy.

Pfizer Inc. (PFE.US) announced on March 18 that its Phase 2 FOURLIGHT-1 study has met its primary endpoint. The results show that its small molecule therapy atirmociclib in combination with fulvestrant significantly improves progression-free survival (PFS) in hormone receptor (HR) positive, human epidermal growth factor receptor 2 (HER2) negative advanced or metastatic breast cancer (MBC) patients who have previously received treatment with cyclin-dependent kinase (CDK) 4/6 inhibitors. These positive results support Pfizer Inc.'s advancement of atirmociclib in first-line treatment and early-stage disease development strategies, aiming to achieve longer-lasting disease control with hormonal therapy in these populations and potentially bring greater clinical benefits. Currently, a Phase 3 registration study of atirmociclib for first-line metastatic breast cancer is ongoing, and results of a Phase 2 study for neoadjuvant therapy in early-stage breast cancer are also expected to be released soon. Atirmociclib is an investigational, potential "first-in-class" oral CDK4 inhibitor. CDK4 is a key factor in regulating the cell cycle process and driving cell proliferation. This drug, discovered by Pfizer Inc., is currently being developed for the treatment of HR positive, HER2 negative breast cancer.