A phase Ib open-label, multicenter study of inhaled DV281, a TLR9 agonist, in combination with nivolumab in patients with advanced or metastatic non-small cell lung cancer

Purpose: Although PD-(L)1 inhibitors have shown efficacy in advanced/metastatic non-small cell lung cancer (NSCLC), many patients do not respond to this treatment and more effective combinations with acceptable toxicities are needed. To assess the potential benefit of combining localized innate immune stimulation with checkpoint blockade, the TLR9 agonist DV281 was combined with nivolumab in a phase Ib study. Patients and Methods: Patients after one or two prior lines of systemic therapy were enrolled in a dose-escalation study with a 3+3 design. DV281 was administered via inhalation in five dose cohorts at 1 to 25 mg; nivolumab 240 mg was administered intravenously every 2 weeks. Safety, tolerability, pharmacodynamics, and response to treatment were assessed. Results: Twenty-six patients with advanced NSCLC enrolled. Baseline programmed death ligand 1 (PD-L1) expression was present in 16 patients (61.5%); 21 (80.7%) had received previous anti-PD-1/PD-L1. Thirteen patients (50%) had stable disease, nine (34.6%) had progressive disease, and four (15.4%) were not evaluable. Median duration of disease control was 124 days. Adverse events were seen in 16 patients (61.5%), mostly grade 1/2 chills, fatigue, flu-like symptoms, diarrhea, and rash; there was only one grade 3 adverse event (dyspnea). Pharmacodynamic assessment, measured by IFN- inducible gene expression, showed target engagement in all dose cohorts. Systemic pharmacodynamic responses plateaued in the 2 highest dose cohorts. Conclusions: DV281 with nivolumab was well tolerated with target engagement observed at every dose. Pharmacodynamic advantages at doses above 10 mg were unclear. The long duration of disease control in 50% of patients suggests clinically relevant activity in this population of heavily pretreated patients.