By Kate Goodwin

Pictured: Merck headquarters/iStock, JHVEPhoto
Phase III results released Tuesday showed Merck’s anti-PD-1 therapy Keytruda is the first to improve overall survival when used as a neoadjuvant and adjuvant treatment versus pre-operative chemotherapy for patients with non-small cell lung cancer, according to the company’s announcement. 
In the KEYNOTE-671 trial, Keytruda plus chemotherapy was given to patients with resectable stage II, IIIA or IIIB non-small cell lung cancer (NSCLC) prior to surgery. After resection, Keytruda was administered as a single agent.  
While the data was not provided in Tuesday's announcement, Merck called the trial the first Phase III to “show a statistically significant overall survival benefit for these patients with stage II, IIIA or IIIB” NSCLC. 
The company said results from the analysis of KEYNOTE-671 will be presented later this month at the European Society for Medical Oncology (ESMO) Congress and shared with global regulatory authorities. 
Previous interim results from March 2023 showed the trial had also met one of its dual primary endpoints for event-free survival. Secondary endpoints achieved include pathological complete response and major pathological response. 
The latest results come just before the FDA’s PDUFA date for Merck’s new supplemental Biologics License Application, submitted after the prior data drop, to get the indication added to Keytruda's ever-growing label. The agency assigned a target action date of Oct. 16.  
Last week, the pharma giant reported Keytruda also met one of its dual primary endpoints in a Phase III bladder cancer trial. An interim analysis review showed a statistically significant and clinically meaningful improvement in disease-free survival compared with simple observation in patients with muscle-invasive urothelial carcinoma. 
Keytruda is projected to be the world’s top-selling drug by a wide margin by 2028, according to Evaluate’s World Preview 2023 report. Already the treatment has generated global sales of more than $12 billion in the first half of 2023. It’s approved for 27 indications so far and listed in over 200 Phase III studies.  
However, it’s not all wins for Merck’s best seller. Last month, Keytruda flopped in two investigational trials combining it with Eisai’s Lenvima for metastatic NSCLC in patients whom EGFR-, ALK- or ROS1-directed therapies were confirmed to be not indicated.
It’s been a series of losses for the partners, previously failing late-stage trials in melanoma, colorectal cancer and head and neck squamous cell carcinoma.