Rakuten Medical to Present Interim Data on ASP-1929 Photoimmunotherapy for Head and Neck Cancer at ASCO 2024

Rakuten Medical, Inc., a global biotechnology firm specializing in precision cell-targeting photoimmunotherapy, has presented promising interim findings from a Phase 1b/2 study (ASP-1929-181/NCT04305795) of ASP-1929 in combination with anti-PD-1 for treating recurrent and/or metastatic head and neck squamous cell carcinoma (HNSCC). The updated safety and efficacy data, analyzed as of August 31, 2023, were announced in San Diego on May 24, 2024, and will be showcased at the 2024 American Society of Clinical Oncology Annual Meeting (ASCO 2024) on June 2, 2024.

The study enrolled 19 patients and demonstrated the potential of ASP-1929 photoimmunotherapy combined with anti-PD-1 in yielding favorable early results for locoregional and metastatic HNSCC patients. Notably, the median overall survival (OS) was not reached at the time of the data cut-off, but the estimated survival rate stood at 52.4% at 24 months. The objective response rate (ORR) was reported at 35.3%, including 4 complete responses (CR) and 2 partial responses (PR). Median progression-free survival (PFS) was 2.9 months.

Safety analysis indicated that adverse events were generally manageable and tolerable. There were no fatal serious adverse events (SAEs), though two Grade 4 SAEs were noted: laryngeal edema related to photoimmunotherapy and tumor hemorrhage unrelated to the treatment. Both conditions were resolved, and no synergistic SAEs were observed from the combination of ASP-1929 and anti-PD-1.

Following these promising interim results, Rakuten Medical concluded a Type B End-of-Phase 2 (EOP2) meeting with the U.S. Food and Drug Administration (FDA). The discussions focused on the design and key aspects of a multi-regional registrational study for this combination treatment in the first-line recurrent HNSCC setting. Plans are in place to initiate a global Phase 3 clinical trial with a primary endpoint of overall survival (OS) in the second half of 2024.

This investigational approach leverages Rakuten Medical's proprietary Alluminox™ platform, which integrates a drug component with targeting moieties and dyes, and a device component that emits light to activate the drug locally. The activation process induces rapid necrosis of targeted cancer cells and potentially stimulates local and systemic immune responses. ASP-1929, the first pipeline drug from the Alluminox platform, is an antibody-dye conjugate comprising cetuximab and IRDye® 700DX. It targets epidermal growth factor receptors (EGFR) on cancer cells, and when activated by red light, it selectively destroys these cells. ASP-1929 has already received Fast Track designation from the FDA and marketing approval in Japan for unresectable locally advanced or recurrent head and neck cancer.

These findings underscore the potential of ASP-1929 photoimmunotherapy combined with anti-PD-1 in improving outcomes for HNSCC patients. While the interim results are encouraging, ongoing studies are essential to confirm these benefits and ensure the therapy's safety and efficacy on a broader scale. As Rakuten Medical prepares for the Phase 3 trial, the medical community awaits further data that could substantiate the use of this innovative treatment in clinical practice.