A phase II study by Riess et al investigating the IO102-IO103 vaccine plus pembrolizumab as first-line treatment in patients with non–small cell lung cancer (NSCLC) showed “promising” overall response rates and 6-month progression-free survival, with an acceptable safety profile. The study (Abstract 756) is being presented during the Society for Immunotherapy of Cancer (SITC) 39th Annual Meeting & Pre-Conference Programs, November 6–10, 2024, in Houston and virtually.

Study Methodology

The researchers enrolled 37 patients with metastatic anti–PD-1 naive NSCLC with a PD-L1 tumor proportion score ≥ 50%, without known targetable mutations in a noncomparative, open-label, multicenter, multicohort trial. The median age of patients was 71 years; 51% were female; and 24% and 65% were current and former smokers, respectively.

The patients received 3-week cycles of subcutaneous IO102-IO103, a first-in-class, dual-antigen, immune-modulatory vaccine that stimulates activation of T cells against indoleamine 2,3-dioxygenase 1 (IDO1) and PD-L1–positive cells in cancer, in combination with pembrolizumab for up to 2 years.

The primary endpoint was overall response rate (ORR) by Response Evaluation Criteria in Solid Tumors version 1.1. Secondary endpoints included progression-free survival and safety.

Key Results

Of the 31 patients considered evaluable for efficacy, 1 had a complete response, and 14 patients had a partial response (confirmed ORR = 48.4%; 95% confidence interval [CI] = 30%–67%); 10 patients (32.3%) had stable disease, and 6 (19.4%) had progressive disease. The researchers found that the disease control rate was 80.6%. Progression-free survival (PFS) rate at 6 months was 61%.

Treatment-related adverse events of any grade were reported in 29 patients (78.4%); 9 (24.3%) were grade ≥ 3, and 3 (8.1%) were serious events. Injection-site reaction was the most common adverse event reported (n = 12; 32.4%), all grade 1 or 2.

“IO102-IO103/pembrolizumab as first-line treatment of PD-L1–high NSCLC showed promising ORR and 6-month PFS rate, with an acceptable safety profile. These data build on the encouraging clinical evidence of IO102-IO103 in combination with [an] anti–PD-1 inhibitor, including earlier reported data in melanoma, NSCLC, and squamous cell carcinoma of [the] head and neck. At the time of data cutoff, a positive trend in median PFS was observed. Longer follow-up for PFS and duration of response, along with exploratory biomarkers, are planned to be presented at the meeting,” concluded the study authors.