NEW YORK – IDRx said on Wednesday that it has raised $120 million in Series B financing to support development of its lead candidate, the KIT inhibitor IDRX-42, in patients with KIT-mutant gastrointestinal stromal tumors (GIST).
The financing was led by RA Capital Management, Commodore Capital, and Blackstone Multi-Asset Investing along with new investors Rock Springs Capital and an unnamed US-based healthcare-focused fund. IDRx's existing investors, including Andreessen Horowitz (a16z) Bio + Health, Casdin Capital, Nextech Invest, Forge Life Science Partners, IDRx Cofounder Nick Lydon, and Merck KGaA, also participated in the financing. Concurrent with the financing, Derek DiRocco, partner at RA Capital Management, has joined the IDRx board of directors.
The Plymouth, Massachusetts-based firm will use the funding to support the ongoing Phase I/Ib StrateGIST 1 trial of IDRX-42. The firm also plans to use the proceeds to launch a pivotal study of IDRX-42 as a second-line treatment for KIT-mutant GIST.
IDRX-42 is designed to target both primary KIT mutations that drive the progression of most cases of GIST as well as secondary resistance. In recent data published from the StrateGIST 1 trial, IDRX-42 demonstrated a 23 percent objective response rate across all GIST patients and a 43 percent response rate in second-line patients.
"IDRX-42 was designed to overcome the twin challenges of on-target treatment resistance and off-target driven adverse events, which limit the clinical benefit of currently available [tyrosine kinase inhibitors]," IDRx CEO Tim Clackson said in a statement. "We are extremely encouraged by the clinical data generated with IDRX-42 to date and are focused on rapidly advancing this potential new treatment option that could elevate the standard of care for GIST patients."
The firm launched in 2022 with IDRX-42, in-licensed from Merck KGaA, and IDRX-73, licensed from Blueprint Medicines. The company is also developing IDRX-73 for GIST. IDRx previously raised $122 million in Series A financing in 2022.