FDA Casts Doubt On Merck's Keytruda Trial Data In Early-Stage Breast Cancer - Merck & Co (NYSE:MRK)

Merck & Co Inc (NYSE: MRK) isn’t likely to win the FDA go-ahead for Keytruda’s use in pre and post-surgery triple-negative breast cancer anytime soon.
The FDA advisory committee voted unanimously to recommend deferral of a regulatory decision on Keytruda (pembrolizumab) to treat patients with high-risk, early-stage triple-negative breast cancer.
The AdCom did not support accelerated approval of pembrolizumab, combined with chemotherapy, due in part to concerns about immature event-free survival and overall survival data from the KEYNOTE-522 trial.
An interim analysis showed that pembrolizumab’s addition to neoadjuvant chemotherapy significantly increased the pathologic complete response rate (64.8% vs. 51.2% in the control arm; percentage-point difference, 13.6%). The most recent interim analysis, including all randomly assigned patients, showed a percentage-point increase of 7.5% with pembrolizumab (63% vs. 55.5%).
Panelists also expressed concerns about immune-related adverse events observed with pembrolizumab among this patient population, with 19% of patients who received pembrolizumab had an unresolved immune-mediated adverse event at the last assessment. Four patient deaths were reported.
Additional data from the KEYNOTE-522 study are anticipated later this year.
Price Action: MRK shares inched lower by 0.35% at $74.78 during market hours on the last check Wednesday.