According to the newspaper Financial Times, the British pharma group is in advanced talks to buy privately owned biotech company IDRx, citing people close to the discussions. The biotech, which was last valued at $430 million at a funding round in August 2024, could be sold for as much as $1 billion, the people added.

Neither GSK nor iDRX have yet commented on the reports.

IDRx, based in Cambridge, Massachusetts, is conducting early-stage trials of its targeted therapy for patients with a type of cancer called gastrointestinal stromal tumor (GIST), which affects between 4,000 and 6,000 people each year in the US.

The available treatments for GIST are not very effective because of resistance mutations in the cancer in 80% of cases, as well as tolerability issues. IDRx’s experimental drug is reported to have shown early signs of addressing this problem.

In a phase-one trial on patients that had already tried two other treatments that had stopped working, the IDRx drug stopped their tumors from growing for nearly 13 months.