Positive Results Seen in Ibrance Breast Cancer Trial

Pfizer announced Ibrance met its primary endpoint in postmenopausal women with human epidermal growth factor receptor 2-negative (ER+, HER2-) advanced or metastatic breast cancer.

Pfizer recently announced promising results from a phase 3 trial for palbociclib (Ibrance) as a first-line treatment for a specific group of breast cancer patients.

PALOMA-2 is a randomized (2:1), multicenter, multinational, double-blind phase 3 study.

Progression free survival (PFS) was evaluated in 666 postmenopausal women with human epidermal growth factor receptor 2-negative (ER+, HER2-) advanced or metastatic breast cancer.

Patients enrolled in the trial had not received previous systemic treatment.

Patients were randomized to receive a combination therapy of Ibrance (125-mg daily for 3 of 4 weeks in repeated cycles) and letrozole (2.5 mg once daily) or letrozole plus placebo as a first-line treatment.

Researchers found that patients receiving the combination of Ibrance and letrozole showed an improvement in PFS compared with patients receiving letrozole and a placebo.

Adverse events experienced with Ibrance and letrozole were said to be consistent with its safety profile.

Ibrance is first-in-class inhibitor of cyclin-dependent kinases (CDKs) 4 and 6.

The drug was initially approved in February 2016 for hormone receptor-positive, HER2-advanced or metastatic breast cancer in combination with fulvestrant in women with disease progression following endocrine therapy.

“PALOMA-2 represents the third randomized study to demonstrate the benefit of Ibrance when added to hormonal therapy in the management of women with ER+, HER2- advanced breast cancer. Ibrance remains the only CDK 4/6 inhibitor with Phase 3 data in this disease,” said Mace Rothenberg, MD, chief medical officer, Pfizer Oncology and senior vice president, Global Product Development, Oncology. “These results provide confirmatory evidence for PALOMA-1 and will be used to support regulatory submissions around the world, including a request for conversion of Ibrance from accelerated to full approval in the United States. We look forward to sharing the detailed results of PALOMA-2 with the oncology community and advancing our discussions with regulatory authorities.”