BARCELONA—For Agios, just running a global randomized phase 3 trial in a tough-to-treat bile duct cancer was a major milestone. The fact that it was positive has the company over the moon.
Monday at the European Society for Medical Oncology annual meeting, the Massachusetts biotech touted results showing its ivosidenib—a compound already approved in acute myeloid leukemia as Tibsovo—could benefit patients with advanced cholangiocarcinoma, an aggressive subtype of bile duct cancer.
Specifically, results from the study, called ClarIDHy, showed that the drug could cut the risk of death by 31% in patients with IDH1 mutations. Patients taking Tibsovo lived a median 10.8 months, compared with 9.7 months on placebo. But adjusting to account for the 57% of placebo patients crossing over to receive the Agios drug, the placebo figure dropped to 6 months, which is significantly shorter than the 10.8 Tibsovo posted.
Agios’ data are the very first to show a clinical benefit with targeted therapy in cholangiocarcinoma, which is “a relatively rare indication overall compared to colorectal cancer and gastric cancer,” Agios Chief Medical Officer Chris Bowden said. It’s also one that “just hasn’t proven very sensitive to any of the therapies that have been developed over the years”—and one that “hasn’t been an area of great interest to drug companies.”
Now, cholangiocarcinoma with IDH1 mutations—who make up up to 20% of the broader cholangiocarcinoma patient pool, could soon have a new option. They number about 2,000 to 3,000 between the U.S. and EU, according to Agios.
But Tibsovo’s success in the population will require doctors to test for the IDH1 mutation, something Bowden said the data show “is important.”
Meanwhile, the company now also boasts a 100% success rate in randomized trials, as the ClarIDHy study marked a first for Agios. It also provided, proof of concept for the drug in solid tumors, as it had only previously been tested in blood cancers.
It was an “important objective for the company and a really important milestone,” Bowden said.