The FDA has granted a full approval to frontline pembrolizumab for use in combination with standard chemotherapy for patients with metastatic nonsquamous non–small cell lung cancer.
The FDA has granted a full approval to frontline pembrolizumab (Keytruda) for use in combination with standard chemotherapy for patients with metastatic nonsquamous non—small cell lung cancer (NSCLC), based on findings from the phase III KEYNOTE-189 trial.
The addition of pembrolizumab to pemetrexed (Alimta) and either cisplatin or carboplatin in the first-line setting reduced the risk of death by 51% in patients with NSCLC without EGFR or ALK mutations.1,2 The median overall survival (OS) was not reached with pembrolizumab cohort compared with 11.3 months (95% CI, 8.7-15.1) in the chemotherapy-alone arm. At a median follow-up of 10.5 months, the estimated 12-month OS rate was 69.2% (95% CI, 64.1-73.8) in the pembrolizumab arm compared with 49.4% (95% CI, 42.1-56.2) in the control group (HR, 0.49; 95% CI, 0.38-0.64; P <.001).
The study also met the coprimary endpoint of progression-free survival (PFS), with a median PFS of 8.8 months (95% CI, 7.6-9.2) in the pembrolizumab group versus 4.9 months (95% CI, 4.7-5.5) in the control arm (HR, 0.52; 95% CI, 0.43 to 0.64; P <.001).
The approval was granted ahead of expectations, under a new FDA approval pathway for supplemental applications. Under the program, called Real-Time Oncology Review, the agency reviews pivotal clinical trial data as soon as it becomes available, prior to the formal submission of an application.
“Over the last few years, we’ve seen significant clinical advances and an incredible shift in the way we approach the treatment of people diagnosed with metastatic non-small cell lung cancer,” Shirish Gadgeel, MD, professor in thoracic oncology at the University of Michigan Rogel Cancer Center, said in a statement. “As a practicing physician, I welcome today’s news, as Keytruda in combination with pemetrexed and platinum chemotherapy significantly prolonged overall survival and progression-free survival in the KEYNOTE-189 trial, compared with chemotherapy alone.”
The prior accelerated approval for pembrolizumab in this setting was based on cohort G in the KEYNOTE-021 trial, in which the 12-month PFS rate was 56% with pembrolizumab combined with pemetrexed and carboplatin compared with 34% with chemotherapy alone (HR, 0.50; 95% CI, 0.29-0.84; P = .0038).3
In the experimental arm (n = 410), patients received pembrolizumab at a 200-mg fixed dose every 3 weeks plus 500 mg/m2 of pemetrexed plus either 75 mg/m2 of cisplatin or carboplatin (AUC 5) on day 1 every 3 weeks for 4 cycles, followed by 200 mg of pembrolizumab plus 500 mg/m2 of pemetrexed every 3 weeks. The regimen administered to the control group (n = 206) was identical, except that pembrolizumab was replaced with placebo.
Patient characteristics were well balanced between the 2 arms. The median age was 65.0 years in the pembrolizumab arm (range, 34.0-84.0), 62.0% of the patients were male, and all but 1 of the patients had an ECOG performance status of 0 or 1. Current/former smokers comprised 88.3% of the cohort and 96.1% of patients had adenocarcinoma.
The pembrolizumab OS benefit was observed across PD-L1 subgroups, including the <1% expression group (12-month OS rate, 61.7% vs. 52.2%; HR, 0.59; 95% CI, 0.38-0.92); the 1% to 49% cohort (12-month OS rate, 71.5% vs. 50.9%; HR, 0.55; 95% CI, 0.34-0.90), and those with a score of 50% or greater (12-month OS rate, 73.0% vs. 48.1%; HR, 0.42; 95% CI, 0.26-0.68).
The objective response rate per blinded, independent central radiologic review was 47.6% (95% CI, 42.6-52.5) in the pembrolizumab arm and 18.9% (95% CI, 13.8-25.0) with chemotherapy alone (P <.001). The disease control rate was 84.6% versus 70.4%, and the median duration of response was 11.2 months versus 7.8 months in the pembrolizumab versus control arms, respectively.
The rate of discontinuation of all study drugs due to adverse events (AEs) was 13.8% in the pembrolizumab arm compared with 7.9% in the control arm. The discontinuation rate of pembrolizumab was 20.2% and placebo was 10.4%. Death related to AEs occurred in 6.7% versus 5.9% of the pembrolizumab versus control arms, respectively.
Diarrhea (30.9% vs 21.3%) and rash (20.2% vs 11.4%) were the only 2 AEs occurring in ≥10% of patients that occurred more commonly in the pembrolizumab versus the chemotherapy-alone arm. Grade ≥3 AEs occurring in at least 10% of patients in either arm were anemia (16.3% with pembrolizumab vs 15.3% in the control group) and neutropenia (15.8% vs 11.9%, respectively).
The rate of acute kidney injury was 5.2% in the pembrolizumab arm versus 0.5% in the chemotherapy-alone arm. Eight patients (2.0%) receiving the PD-1 inhibitor had grade ≥3 acute kidney injury.
Immune-mediated AEs occurred in 22.7% of the pembrolizumab group versus 11.9% of the control group, including grade ≥3 AEs in 8.9% versus 4.5%, respectively. Pneumonitis led to 3 deaths in the pembrolizumab cohort.
The double-blind phase III KEYNOTE-189 study accrued 616 patients with advanced or metastatic nonsquamous NSCLC, regardless of PD-L1 expression. Patients were not EGFR- or ALK-positive, and had not received systemic therapy for advanced disease. The trial randomization was 2:1 in favor of the pembrolizumab arm.