Rakuten Medical, a San Diego-based biotechnology company developing its Alluminox platform-based photoimmunotherapy, has closed a $100 million oversubscribed Series F financing to support a global Phase 3 program for its lead investigational therapy ASP-1929 and advance toward a planned U.S. Biologics License Application submission in 2028.
The round includes $70 million of new capital and the conversion of $30 million in convertible promissory notes plus accrued interest. Rakuten Medical said the upsized financing was double its initial target, citing strong investor demand and confidence in the company’s ability to execute on late-stage development and global expansion.
Proceeds will primarily fund the company’s top near-term objective: securing U.S. regulatory approval for ASP-1929, its first investigational drug developed on the Alluminox platform. Rakuten Medical is enrolling patients in a global Phase 3 trial (ASP-1929-381, NCT06699212) evaluating ASP-1929 photoimmunotherapy in combination with pembrolizumab as a first-line treatment for recurrent head and neck cancer. The company said the financing will help expand operational capacity and speed enrollment across trial geographies including the U.S., Taiwan, Japan, Ukraine, and Poland.
Alongside the U.S. push, Rakuten Medical said it is leveraging regulatory materials and post-market real-world evidence from Japan—where the therapy is approved and commercialized as Akalux (ASP-1929) used with the BioBlade Laser System device—to support additional international regulatory filings. The company emphasized that its photoimmunotherapy approach remains investigational outside Japan, and it plans to work with strategic partners with regional regulatory expertise to accelerate expansion efforts.
Rakuten Medical also outlined plans to broaden clinical development beyond head and neck cancer through internal programs and investigator-initiated trials supported by grants and other external funding sources. In Japan, the company expects to initiate a Phase 1 trial for RM-0256 photoimmunotherapy in solid tumors, including malignant skin tumors, in the second quarter of 2026 with support from a Japan Agency for Medical Research and Development (AMED) grant. The company also plans to support ongoing investigator-initiated studies in esophageal and gynecologic cancers in Japan and is preparing additional investigator-initiated work in pancreatic cancer and non-small cell lung cancer in the U.S., potentially backed by external grants.
Commercially, Rakuten Medical said it intends to continue growing sales of ASP-1929 photoimmunotherapy for head and neck cancer in Japan, positioning the Japanese business as a source of profitability and a longer-term funding engine to support broader global development and expansion.
The Series F financing was led by TaiAx Life Science Fund L.P., an international life science venture capital fund jointly established by Taiwania Capital Management in Taipei and Japan-based Axil Capital Group. Rakuten Medical said the round attracted the largest institutional investor group in its history, including Japanese financial institutions Daiwa Securities, Mitsui Sumitomo Insurance, and Sumitomo Mitsui Banking, as well as Taiwanese venture firms ABIES Capital and Nexus CVC. Strategic partner OEP Group joined the syndicate, alongside existing investors including SBI Group, Rakuten Group, and Rakuten founder and executive Mickey Mikitani, who also serves as Rakuten Medical’s CEO.
Rakuten Medical’s platform integrates a drug component—an antibody-dye conjugate designed to bind tumor-associated targets—with a medical device that delivers localized red-light illumination to activate the therapy. ASP-1929 combines the anti-EGFR antibody cetuximab with a light-activatable dye, and the company says targeted illumination triggers selective cell killing at the tumor site. In Japan, ASP-1929 received marketing approval in September 2020 for unresectable locally advanced or recurrent head and neck cancer under the Sakigake Designation System and the Conditional Early Approval System, while global development efforts now focus on generating Phase 3 data to support potential approvals in additional markets.
KEY QUOTES:
“Securing significant investment from leading life science investors underscores the strength of our technology and the excellence of our team. The Alluminox platform underlines a new treatment modality that requires advanced expertise in both drug development and medical device technology. Rakuten Medical is tightly focused and mission driven, having successfully developed, received approval for and commercialized an innovative therapy in 15 years. This financing will enable us to accelerate clinical development, expand our global reach and prepare for the next phase of growth.”
Mickey Mikitani, CEO, Rakuten Medical (and Chairman and CEO, Rakuten Group)
“This oversubscribed Series F financing reflects our strong conviction in Rakuten Medical’s differentiated technology and its ability to address profound unmet medical needs. We are thrilled to lead this round and to form a strong, like-minded global syndicate united by a shared vision to advance the future of cancer care.”
Michael Huang, Managing Partner, Taiwania Capital Management
