Rakuten Medical reels in another megaround to fund cancer R&D

Rakuten Medical has raised $100 million to advance its pipeline of photoimmunotherapy oncology prospects. The biotech hopes to use antibodies and light to destroy cancer cells while leaving healthy tissues unharmed. 

Since setting up shop in 2015, Rakuten Medical, formerly known as As­pyr­i­an Ther­a­peu­tics, has raised close to $500 million to invest in development of photoimmunotherapy candidates. The idea is to conjugate antibodies to a dye that responds to a certain type of light. Once the drug binds to the target antigen, exposure to light triggers anti-cancer effects, thereby driving the precision destruction of tumors.

That hypothesis has attracted the support of Mickey Mikitani, the Japanese billionaire who made his money by setting up and running online retailer Rakuten. Working through organizations including Rakuten, Mikitani made a series of investments in As­pyr­i­an, culminating in the biotech changing its name earlier this year.

Rakuten provided the latest $100 million financing, bringing its stake in the biotech that took its name up to 22.6%. Mikitani now plans to make strategic connections between the two organizations. 

"Culturally, the technology industry has revolutionized society by being bold, action-driven and innovative; and we hope to do the same at Rakuten Medical by exploring opportunities that will combine Rakuten's technology expertise with Rakuten Medical's first-in-class photoimmunotherapy platform," Mikitani, who now serves as CEO of the biotech, said in a statement.

In the near term, the focus at Rakuten Medical is on a phase 3 trial in recurrent head and neck squamous cell carcinoma that will provide the most rigorous test of photoimmunotherapy to date. The candidate in that trial, ASP-1929, consists of cetuximab—the anti-EGFR antibody better known as Erbitux—conjugated to the dye IRDye 700DX. Rakuten Medical plans to trial ASP-1929 in other cancers as well.