RAPT Therapeutics Announces Positive Data, Including Objective Response Rates and Progression-Free Survival, from its Phase 2 Trial of FLX475 in Combination with a Checkpoint Inhibitor in Patients with Advanced NSCLC

- Confirmed objective response rate (ORR) of 40% in PD-L1 positive (TPS ≥1%) patients with no prior checkpoint inhibitor therapy (CPI)

- Median progression-free survival (PFS) of 6.3 months in PD-L1 positive patients at time of data cut off

- Confirmed ORR of 50% in patients with PD-L1 high expression (TPS ≥50%) and 38% in patients with PD-L1 low expression (TPS 1-49%)

- RAPT to host webcast conference call today at 10:00 am PT

SOUTH SAN FRANCISCO, Calif., Nov. 03, 2023 (GLOBE NEWSWIRE) -- RAPT Therapeutics, Inc. (Nasdaq: RAPT), a clinical-stage, immunology-based therapeutics company focused on discovering, developing and commercializing oral small molecule therapies for patients with significant unmet needs in inflammatory diseases and oncology, today announced safety and efficacy data from its Phase 2 trial of FLX475 (tivumecirnon) in patients with advanced non-small cell lung cancer (NSCLC) who had no prior checkpoint inhibitor therapy. The trial evaluated FLX475, an oral small molecule CCR4 antagonist designed to block the migration of regulatory T cells, in combination with the checkpoint inhibitor pembrolizumab. In this cohort of NSCLC patients, 36 patients were evaluable for efficacy, of which 20 were PD-L1 positive. In these PD-L1 positive patients, the combination of FLX475 and pembrolizumab showed a 40% (8/20) confirmed ORR and a median PFS of 6.3 months as of the data cut off date, with seven patients continuing on study. For comparison, historical pembrolizumab monotherapy activity in checkpoint inhibitor-naïve and previously-treated NSCLC patients showed a confirmed ORR of 18% and a median PFS of 4.0 months. The confirmed ORR for the combination of FLX475 and pembrolizumab in PD-L1 low and high subsets were 38% (6/16) and 50% (2/4), respectively. For comparison, the ORR for pembrolizumab monotherapy in the PD-L1 low and high subsets has been previously reported as 10% and 30%, respectively.

The data were presented today in a poster at the Society for Immunotherapy of Cancer (SITC) 38^th Annual Meeting being held in San Diego. The presenting author was Julie Brahmer, M.D., Co-director of the Upper Aerodigestive Department and Professor of Oncology, Johns Hopkins University.

“We are excited by the response rates and PFS data for FLX475 in combination with a checkpoint inhibitor in this cohort of NSCLC patients. The data from this cohort, which will continue to mature and potentially improve, met our criteria to advance development of FLX475,” said Brian Wong, M.D., Ph.D., President and Chief Executive Officer of RAPT. “We are particularly intrigued to see differentiating efficacy in patients with cool (PD-L1 low) tumors, which are typically poorly responsive to checkpoint inhibitors and checkpoint inhibitor combinations, such as those with anti-TIGIT antibodies. Along with RPT193, we now have two internally discovered compounds that have demonstrated clinical proof of concept in large, commercially attractive indications.”