Under new leadership, IDRx has raised $120 million to push its targeted treatment for a rare digestive tract cancer through early-stage studies.
The company plans to use the money to continue clinical studies of a targeted drug for GIST — a type of tumor that grows in the digestive tract lining. The therapy, known as IDRX-42, goes after tumors with a KIT mutation, which is found in over 80% of GIST cases.
The company’s Series B raise was led by RA Capital, Commodore Capital, and Blackstone. It’s the latest in a string of biotech rounds that have exceeded $100 million.
In March, IDRx brought in former Theseus executives Tim Clackson and Brad Dahms to lead the company as CEO and CFO, respectively. Former CEO Ben Auspitz now chairs the board for IDRx, a company he started with serial biotech entrepreneur Alexis Borisy.
Theseus had also been developing an experimental drug for GIST but discontinued its lead program after the drug ran into tolerability problems.
“GIST has very well understood biology, but it has been a challenging chemistry problem,” Dahms told Endpoints News in an interview. He added the goal is to “thread that needle” of eliciting deep, durable responses, while also ensuring a tolerable treatment.
At ASCO in June, IDRx presented early clinical results that showed its treatment shrunk tumors in 23% of patients, regardless of how many prior regimens they had tried, and 43% in second-line patients.
A key point with future clinical data will be how long the treatment continues to work — people can live with GIST tumors for a long time and many survive past five years.
“You’re treating patients for a very long time, so the duration element is key,” said Clackson in the joint interview. He pointed to what he described as “eye-popping” data from ASCO of Pfizer’s targeted lung cancer drug Lorbrena, which is for mutations in a gene called ALK. In the five-year follow-up analysis, 50% of patients in the study were still receiving the drug.
“Those are the kinds of aspirations we have,” Clackson said.
The next step is to continue the Phase 1b part of the trial, where the company has selected a dose it wants to move forward with, Dahms said. Clackson noted that IDRx plans to provide a follow-up readout on its early-stage study in the fourth quarter of this year.
IDRx’s goal is to reach a pivotal study around the “middle of 2025,” Dahms said.
In the world of GIST, Ono Pharmaceutical in April announced plans to acquire Deciphera and its GIST drug Qinlock for $2.4 billion. Blueprint Medicines, which Borisy also co-founded, won the first approval for a targeted GIST treatment Ayvakit in 2020 for a small subset of patients with a specific mutation. Blueprint has since developed Ayvakit primarily into a drug for a rare white blood cell disorder.
IDRx licensed IDRX-42 from Merck KGaA.