Posted: Monday, September 12, 2022
In the phase III KEYNOTE-189 trial, pembrolizumab plus pemetrexed and platinum seemed to demonstrate improved clinical activity versus a placebo plus pemetrexed and platinum in patients with previously untreated, metastatic nonsquamous non–small cell lung cancer (NSCLC) without sensitizing EGFR/ALK alterations, regardless of the PD-L1 tumor proportion score. Results of the 5-year follow-up analysis, which were presented by Marina C. Garassino, MD, of the University of Chicago, and colleagues during the European Society for Medical Oncology (ESMO) Congress 2022 (Abstract 973MO), further support the adoption of this combination as a standard of care.
“First-line pembrolizumab plus pemetrexed and platinum continued to show overall and progression-free survival benefits with manageable toxicity…irrespective of PD-L1 expression,” the investigators remarked. “Patients who completed 35 cycles of pembrolizumab experienced durable responses.”
A total of 616 patients were randomly assigned in a 2:1 ratio to receive up to 35 cycles of 200 mg of pembrolizumab or a placebo once every 3 weeks in combination with 4 cycles of pemetrexed plus the investigator’s choice of carboplatin or cisplatin. Maintenance therapy with pemetrexed was administered until disease progression or unacceptable toxicity. After experiencing disease progression, patients were permitted to cross over from the placebo to pembrolizumab monotherapy.
The median duration of overall survival was longer with pembrolizumab than with the placebo (22.0 vs. 10.6 months); the 5-year overall survival rates were 19.4% and 11.3%, respectively. The median duration of progression-free survival was 9.0 months with pembrolizumab and 4.9 months with the placebo. The incidence rates of grade 3 to 5 adverse events were 72.8% and 67.3%, respectively, among patients who were administered at least one dose of the assigned treatment. Among the 57 patients who completed 35 cycles of pembrolizumab, the objective response rate was 86.0%, and the 3-year overall survival rate was 71.9%.
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