Tolerability and antitumor activity of cemiplimab, a human monoclonal anti–PD-1, as monotherapy in patients with pretreated non-small cell lung cancer (NSCLC): data from the Phase 1 NSCLC expansion cohort

Abstract Objectives Blockade of programmed cell death-1 (PD-1) and its ligand (PD-L1) has transformed the treatment of NSCLC. In a first-in-human, Phase 1, dose escalation and cohort expansion study, cemiplimab, a monoclonal antibody directed against PD-1, was evaluated for the treatment of patients with advanced solid tumors (NCT02383212). Here, we report results in patients with advanced NSCLC from the dose expansion cohort. Materials and methods Immune-checkpoint inhibitor naive patients with advanced NSCLC (stage III/IV), irrespective of PD-L1 status, who had progressed after, or were refractory to first- or later-line therapy were enrolled and received cemiplimab 200 mg every 2 weeks intravenously for up to 48 weeks. Primary study objectives were to assess safety and tolerability, and to evaluate clinical activity of cemiplimab. Results Twenty patients with NSCLC were enrolled. Median age was 64.0 years (range: 50‒82); 65.0% were male; 80.0% had an ECOG performance status of 1; 60.0% had a histology of adenocarcinoma. Median number of prior lines of systemic therapy was 2 (range: 1–4). Median duration of follow-up was 7.0 months (range: 1.0–18.2). All patients experienced ≥1 treatment-emergent adverse event (TEAE) of any grade. Most common TEAEs were arthralgia, asthenia, cough, and dyspnea (each 4/20; 20.0%). Grade ≥3 TEAEs occurred in 60.0% (12/20) of patients. Of patients with measurable disease per independent central review (ICR), five had partial response (PR), four had stable disease (SD) and 10 had progressive disease. Objective response rate (ORR; complete response + PR) was 25.0% (95% CI: 8.7–49.1%). Duration of response exceeded 8 months in four of the five responding patients at the time of data cut-off (April 30, 2019). The disease control rate per ICR (ORR + SD) was 50.0% (95% CI: 27.2–72.8%). Conclusion Cemiplimab showed an acceptable safety profile and demonstrated antitumor activity in pretreated patients with NSCLC.