ASCO: Keytruda Scores Phase III NSCLC Win, Outperforms AstraZeneca’s Imfinzi

Pictured: Merck logo on building/iStock, Sundry Photography

Pictured: Merck logo on building/iStock, Sundry Photography

Saturday, Merck released highly anticipated data from its Phase III KEYNOTE-671 trial of Keytruda (pembrolizumab) plus chemotherapy as a perioperative treatment regimen in resectable stage II, IIIA or IIIB non-small cell lung cancer at the 2023 American Society of Clinical Oncology annual meeting.

For patients in the combination treatment arm, Keytruda was administered in combination with chemotherapy before surgery and as a single agent after surgery. Compared to those treated with chemotherapy and placebo, the combination significantly improved event-free survival (EFS), one of two primary endpoints, and reduced the risk of disease recurrence, progression or death by 42%. 

That was enough to distinguish Keytruda from its main competitor: AstraZeneca’s Imfinzi (durvalumab). 

In April, the British biopharma released data from the Phase III AEGEAN trial studying Imfinzi before and after surgery in patients with resectable stage II, IIIA or IIIB NSCLC. Those treated with Imfinzi showed a 32% EFS rate, compared to Keytruda’s 42% in KEYNOTE-671.

Merck also noted that “a favorable trend” was observed in the study’s other primary endpoint, overall survival, but stated these data “are not mature and did not reach statistical significance.” The trial will continue to allow for additional follow-up analysis of this endpoint, according to the company.  

The trial enrolled a total of 797 patients with resectable stage II, IIIA or IIIB NSCLC. The results will be presented during a clinical science symposium at ASCO and simultaneously published in the New England Journal of Medicine. 

According to the press release, these data mark the eighth trial evaluating a Keytruda-based regimen in patients with earlier stages of cancer to meet its primary endpoint.

Keytruda also met key secondary endpoints, including pathological complete response (pCR) and major pathological response (mPR).

Daina Graybosch, senior managing director and biotechnology analyst for immuno-oncology at SVB Securities, previously told BioSpace that if the data were positive, it could lead to a major label expansion for Keytruda in even earlier stages of NSCLC, adding that it has the potential to be the “most practice-changing impact data” in lung cancer presented at this year’s ASCO. 

Merck’s new supplemental Biologics License Application for Keytruda in earlier-stage NSCLC has been accepted by the FDA, with an Oct. 16 decision date looming that could move Keytruda into resectable stage II, IIIA or IIIB NSCLC in combination with chemotherapy prior to surgery (neoadjuvant) and as a single agent post-surgery (adjuvant).

Also on Merck’s list to present at ASCO are long-term data from the KEYNOTE-826 trial, which studied Keytruda added to standard chemotherapy, with or without Genentech (Roche)'s Avastin (bevacizumab), in metastatic, recurrent or persistent cervical cancer.

The company will also present data from a final, pre-specified analysis of the Phase III CLEAR/KEYNOTE-581 trial studying Keytruda with Eisai’s Lenvima (lenvatinib) in advanced renal cell carcinoma.

Rosemary Scott is an editor at BioSpace, focusing on the job market and career development for professionals in the life sciences. You can reach her at and on LinkedIn.

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