Brief Report: Safety and Antitumor Activity of Durvalumab Plus Tremelimumab in Programmed Cell Death-(Ligand)1-Monotherapy Pretreated, Advanced NSCLC: Results From a Phase 1b Clinical Trial

Introduction: Although first-line immunotherapy approaches are standard, in patients with non-small cell lung cancer (NSCLC) previously treated with programmed cell death protein-1 or programmed death-(ligand)1 (PD-[L]1) inhibitors, the activity of combined CTLA-4 plus PD-(L)1 inhibition is unknown. This phase 1b study evaluated the safety and efficacy of durvalumab plus tremelimumab in adults with advanced NSCLC who received anti-PD-(L)1 monotherapy as their most recent line of therapy.

Methods: Patients with PD-(L)1-relapsed or refractory NSCLC were enrolled between October 25, 2013, and September 17, 2019. Durvalumab 20 mg/kg plus tremelimumab 1 mg/kg was administered intravenously every 4 weeks for four doses, followed by up to nine doses of durvalumab monotherapy every 4 weeks for up to 12 months of treatment or disease progression. Primary end points included safety and objective response rate (ORR) on the basis of Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) per blinded independent central review; secondary end points were ORR on the basis of RECIST v1.1 per investigator; duration of response, disease control, and progression-free survival on the basis of RECIST v1.1 per blinded independent central review and investigator; and overall survival.

Clinicaltrials: gov identifier: NCT02000947.

Results: PD-(L)1-refractory (n = 38) and PD-(L)1-relapsed (n = 40) patients were treated. The most common treatment-related adverse events were fatigue (26.3%, PD-(L)1-refractory patients) and diarrhea (27.5%, PD-(L)1-relapsed patients). Grade 3 to 4 treatment-related adverse events occurred in 22 patients. Median follow-up duration was 43.6 months for PD-(L)1-refractory patients and 41.2 months for PD-(L)1-relapsed patients. The ORR was 5.3% for PD-(L)1-refractory patients (one complete response, one partial response) and 0% for PD-(L)1-relapsed patients.

Conclusions: Durvalumab plus tremelimumab had a manageable safety profile, but the combination did not have efficacy after PD-(L)1 treatment failure.