Aim: To present updated results of a phase 1/2 study of nivolumab (N) alone or in combination with ipilimumab (I) in pretreated patients with SCLC.
Methods: Patients with progressive disease, regardless of platinum sensitivity, tumor programmed death ligand-1 expression, or number of prior chemotherapy regimens, were assigned to intravenous N 3 mg/kg Q2W or N+I (1+1 mg/kg or 1+3 mg/kg) Q3W for 4 cycles, followed by N 3 mg/kg Q2W. Primary objective was overall response rate (ORR). Additional objectives included safety, progression-free survival, overall survival, and biomarker analysis.
Results: Ninety patients were enrolled (N, n=40; N1+I1, n=3; N1+I3, n=47); 53% had ≥2 prior regimens. ORR was 18% (7/39), 33% (1/3), and 17% (7/42) in the N, N1+I1, and N1+I3 arms, respectively, with corresponding median durations of response of 4.1–11+, 11.1+, and 1.5–6.9+ months. Eight patients (20%) in the N arm, 1 (33%) in the N1+I1 arm, and 20 (43%) in the N1+I3 arm remain on treatment. Three patients (8%) treated with N, zero with N1+I1, and 5 (11%) with N1+I3 discontinued due to treatment-related adverse events (TRAEs). Grade 3–4 TRAEs occurred in 6 patients (15%) with N (stomatitis, fatigue, amylase increase, g-glutamyl transpeptidase increase, hyperglycemia, encephalitis in 1 patient each), zero patients with N1+I1, and 16 patients (34%) with N1+I3 (in ≥2 pts [4%]: diarrhea 8.5%, increased lipase 6.4%, vomiting 4.3%, rash 4.3%, rash maculo-papular 4.3%, and dermatitis 4.3%). Two patients (grade 1–2) in the N arm and 1 (grade 3–4) in the N1+I3 arm experienced treatment-related pneumonitis. One fatal case of treatment-related myasthenia gravis occurred in the N1+I3 arm.
Conclusions: Patients with SCLC treated with N or N+I achieved durable responses after progressing on platinum-based therapy. The safety profile was consistent with that observed in other tumors, and was manageable with established safety guidelines.