The addition of pembrolizumab to first-line chemotherapy extended PFS but failed to significantly extend OS among patients with extensive-stage small cell lung cancer, according to topline data released by the agent’s manufacturer.
Small cell lung cancer accounts for 10% to 15% of lung cancer cases. An estimated 6% of patients survive 5 years.
The randomized, phase 3 KEYNOTE-604 study included 453 patients with newly diagnosed extensive-stage small cell lung cancer.
Researchers randomly assigned patients to the anti-PD-1 therapy pembrolizumab (Keytruda, Merck) plus chemotherapy or chemotherapy alone.
Patients assigned pembrolizumab received 200 mg on day 1 of each 21-day cycle. Chemotherapy consisted of etoposide dosed at 100 mg/m2 on days 1, 2 and 3, as well as investigator's choice of platinum chemotherapy.
OS and PFS served as dual primary endpoints. Secondary endpoints included objective response rate, duration of response, safety and quality of life.
Results of a prior interim analysis revealed a significant PFS improvement with pembrolizumab (HR = 0.75; 95% CI, 0.61-0.91).
Results of the final analysis showed longer OS in the pembrolizumab group (HR = 0.8; 95% CI, 0.64-0.98); however, the difference did not reach statistical significance per the prespecified statistical plan.
Pembrolizumab exhibited a safety profile consistent with that observed in previous studies.
Complete results of KEYNOTE-604 will be submitted for presentation at a future scientific meeting. Healio will provide an update when those results are available.
Pembrolizumab previously received FDA approval for five lung cancer indications. The agent also is approved for treatment of certain patients with head and neck squamous cell carcinoma, melanoma, hepatocellular carcinoma, classical Hodgkin lymphoma, primary mediastinal large B-cell lymphoma, urothelial carcinoma, gastric cancer, cervical cancer, Merkel cell carcinoma and microsatellite instability-high cancers.