Merck & Co – known as MSD outside the US and Canada – has shared positive phase 3 results for its Keytruda (pembrolizumab) in combination with chemotherapy (CRT) in patients with high-risk, early-stage triple-negative breast cancer (TNBC).
The PD-1 therapy is the first and only immunotherapy-based regimen to show a statistically significant improvement in overall survival (OS) as a pre-operative treatment with CRT and as a single agent after surgery compared to pre-operative chemotherapy in this patient population.
Accounting for 24% of newly diagnosed cancers worldwide, TNBC is one of the most aggressive forms of breast cancer and has the highest risk of recurrence within the first five years after diagnosis.
Cancer cells in TNBC do not contain oestrogen or progesterone receptors and do not produce much of the HER2 protein.
The KEYNOTE-522 study has been evaluating Keytruda in combination with CRT in 1,174 patients with TNBC and is the fourth study of a Keytruda-based regiment in an earlier stage of cancer to demonstrate an OS benefit.
Results showed that Keytruda demonstrated a statistically significant and clinically meaningful OS compared to pre-operative CRT, with a safety profile that remained consistent with that observed in previous studies and no new safety signals.
Dr Gursel Aktan, vice president, global clinical development, Merck Research Laboratories, commented: “To have achieved OS from this landmark study is highly encouraging and builds upon the positive pathological complete response and event-free survival results that led to approvals for this regimen around the world.”
Already approved in the US for two indicated in TNBC, Keytruda works to enhance the immune system’s ability to detect and fight tumour cells.
Results from the study come after Merck shared positive phase 3 results from the KEYNOTE-A18 trial, which showed that Keytruda with concurrent CRT had a statistically significant and clinically meaningful improvement in OS newly diagnosed patients with high-risk locally advanced cervical cancer, compared to concurrent CRT alone and met its primary endpoint of progression-free survival.
Most recently, Merck’s Keytruda received approval from the European Commission in March for expanded lung cancer use, based on results from the phase 3 KEYNOTE-671 trial.