A phase II study of durvalumab (MEDI4736) for previously treated patients with stage IV squamous NSCLC (SqNSCLC): Lung-MAP Sub-study SWOG S1400A

Abstract

Background: Durvalumab (MEDI4736) is an engineered human IgG1mAb targeting programmed cell death ligand-1 (PD-L1). Treatment with other anti-PD-1/PD-L1 antibodies has demonstrated meaningful clinical benefit in patients with advanced NSCLC. Methods: As part of the Lung Master Protocol S1400, a National Clinical Trials Network group “umbrella” trial for second-line SqNSCLC we conducted a phase II study of durvalumab in patients with Stage IV squamous NSCLC (ECOG PS 0-2; 1 prior systemic treatment regimens, including one platinum-based), EGFR/ALK wildtype. The primary endpoint was overall response rate (ORR) (RECIST v1.1); secondary endpoints included duration of response (DoR), ORR among PD-L1 positive patients disease control rate (DCR), investigator-assessed progression-free survival (PFS), overall survival (OS) and safety (CTCAE v4.03). The initial protocol was a randomized phase II/III comparison of durvalumab to docetaxel, and was amended to be a single arm phase II trial of single agent durvalumab. PD-L1 positive tumors were defined by 25% of tumor cells with membrane staining. Results: Of the 68 eligible patients (median [range] age 66 [35-92] years, PS 0/1/2 26%/62%/12%), 11 were responders (16% ORR, 95% Confidence Interval [CI] 7%, 25%). DCR was 54% (CI 43%, 66%), median OS was 11.5 months (CI 10.1-12.4 mos), and median PFS was 2.9 mos (CI 2.0-4.1 mos). Of the 11 responders, median time to response and DoR were 3.6 mos (CI 2.8-4.2 mos) and 18.6 months (95% CI 4.4-NR mos), respectively. Of the 14 PDL1-positive patients, 2 were responders (14% ORR 95% CI 0%, 33%), DCR was 57% (CI 31%, 83%), median OS and PFS were 10.7 mos (CI 9.2-10.7 mos) and 2.3 mos (CI 1.4-4.9 mos), respectively. Durvalumab showed a manageable safety and tolerability profile; most adverse events (AEs) were low grade and resolved with treatment delay and/or immunosuppressive interventions. Grade 3 treatment-related AEs occurred in 23(34%) of patients. Drug-related AEs led to discontinuation in 6 patients (9%, 95% CI 2%, 16%). Conclusions: Durvalumab demonstrated clinical benefit and durable responses in a previously treated metastatic NSCLC population with manageable toxicity profile. Results are comparable with other anti-PD-1/PD-L1 therapies in metastatic, relapsed NSCLC.