Ibrance disappoints on OS in new Phase III breast cancer trial

Blockbuster drug Ibrance (palbociclib) combined with fulvestrant was not statistically significant in extending overall survival (OS) in certain patients breast cancer patients, the secondary endpoint of a late-stage trial.

Pfizer (NYSE: PFE) has announced OS results from the Phase III PALOMA-3 trial, which evaluated Ibrance in combination with fulvestrant compared to placebo plus fulvestrant in women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer whose disease has progressed after prior endocrine therapy.

The results demonstrated a positive trend in the hazard ratio favoring the Ibrance combination, although this trend did not reach statistical significance. Overall survival is a secondary endpoint of the PALOMA-3 trial and, as such, the trial design was not optimized to detect a statistically significant difference in OS.