Pfizer Stops Ibrance Trial Early Due to Efficacy

Interim results of a Phase III clinical trial of Pfizer’s Ibrance breast cancer drug were so good that the drugmaker has halted the study.

Patients showed clear improvement in progression-free survival in the trial, which compared Ibrance (palbociclib) plus AstraZeneca’s Faslodex (fulvestrant) with Faslodex and placebo in patients with hormone receptor positive, HER2- metastatic breast cancer whose disease had progressed following endocrine therapy.

The FDA granted Ibrance accelerated approval in February as a first-line treatment for women with metastatic estrogen receptor positive, HER2- breast cancer, based on results of a Phase II trial that showed patients gaining approximately 10 months of progression-free survival.

Pfizer’s not likely to see a major boost in sales should the FDA approve Ibrance for this latest indication because most metastatic breast cancer patients will opt for the drug first line, says Evercore ISI analyst Mark Schoenebaum.

But the positive results should lend weight to the Phase III confirmatory trial the drugmaker is conducting to support full regulatory approval, he adds. — Lena Freund