FDA Rejects Merck's Keytruda Application In High-Risk Breast Cancer Patients

The FDA slapped Merck & Co Inc’s MRK Keytruda with a complete response letter in high-risk triple-negative breast cancer, in combination with chemotherapy as neoadjuvant treatment, then continuing as a single agent as adjuvant treatment after surgery.

• Merck is reviewing the letter and will discuss the next steps with the FDA.
• Last month the agency’s Oncologic Drugs Advisory Committee unanimously recommended the deferral of a regulatory decision on the immuno-oncology therapy.
• 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.
• The marketing application was based on pCR data and early interim event-free survival findings from the Phase 3 KEYNOTE-522 trial, continuing to evaluate for survival. 
• The following interim analysis will occur in the third quarter of this year.
• The letter does not affect Keytruda’s approval as a combination therapy with chemo in locally advanced PD-1 expressing TNBC tumors, metastatic or cannot be surgically removed.
• Price Action: MRK shares closed 1.7% higher at $78.3 on Monday.