GSK nears US $1 billion deal for IDRx’s targeted therapy for rare tumor

U.K. – GSK is reportedly in advanced talks to acquire IDRx, a privately-held biotech company, in a deal valued at approximately US $1 billion.

This acquisition would center around IDRx’s experimental therapy, IDRX-42, designed to treat a rare form of gastrointestinal stromal tumor (GIST).

The rumored transaction, first reported by the Financial Times, is expected to coincide with the upcoming JPMorgan Healthcare Conference, a key event known for sparking mergers and acquisitions in the biopharma sector.

IDRx, headquartered in Cambridge, Massachusetts, is backed by prominent investors such as Andreessen Horowitz, RA Capital, and Blackstone Group.

Last August, the company raised US $120 million in a Series B funding round, bringing its valuation to about US $430 million.

The funds were intended to support the clinical development of IDRX-42, particularly its phase 1/1b StrateGIST 1 trial, and to prepare for a pivotal trial of the drug. The company had also been exploring the possibility of a public listing.

The StrateGIST 1 trial is testing IDRX-42, a selective KIT inhibitor, in patients with KIT-mutant GIST who have failed previous therapies, including Novartis’ Gleevec (imatinib mesylate) and other targeted drugs.

Results from the phase 1 portion of the trial, presented at the ASCO cancer conference last year, showed promising outcomes.

Among patients who had received a median of four prior treatments, the drug demonstrated a 23% objective response rate (ORR). In patients treated as a second-line therapy, the ORR rose to 43%.

For GSK, this acquisition aligns with its strategy to rebuild its oncology pipeline after largely exiting the field a decade ago when it sold its cancer assets to Novartis.

In recent years, GSK has made a series of strategic acquisitions to strengthen its portfolio, including its US $1.9 billion purchase of Sierra Oncology in 2022, adding the myelofibrosis drug Omjjara (momelotinib).

Additionally, the company has invested in antibody-drug conjugates from Hansoh Pharma, worth US $1.7 billion and $1.58 billion, and made smaller deals with Rgenta Therapeutics and Duality Biologics.

This push into oncology comes as GSK faces looming challenges, such as the 2027 patent expiration of its blockbuster HIV drug dolutegravir and increasing competition for its shingles vaccine Shingrix, which is currently its top-selling product.

Neither GSK nor IDRx has commented on the rumored negotiations. However, if the deal is finalized, it could mark another significant step in GSK’s effort to solidify its presence in the oncology space.

GIST, though a rare cancer, is the most common type of soft tissue sarcoma in the gastrointestinal tract, affecting 4,000 to 6,000 people annually in the United States, according to IDRx.

Approximately 80% of these cases are driven by mutations in the KIT gene, making IDRX-42 a potentially transformative therapy for this patient population.