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Agios's Tibsovo Trial Fails to Meet Overall Survival Endpoint in IDH1-Mutated Bile Duct Cancer

NEW YORK – Agios Pharmaceuticals said on Monday that its Phase III ClarIDHy trial did not demonstrate a statistically significant survival advantage for ivosidenib (Tibsovo) in patients with IDH1-mutated cholangiocarcinoma compared to placebo.

The ClarIDHy has already met its primary endpoint by demonstrating that patients with IDH1-mutated tumors on ivosidenib had a median progression-free survival of 2.7 months compared to 1.4 months on placebo. 

The Cambridge, Massachusetts-based firm now plans to submit this data with the US Food and Drug Administration in a supplemental new drug application in Q1 2021 and to seek approval for the drug in previously-treated IDH1-mutant cholangiocarcinoma, a type of bile duct cancer. Approximately 10 percent of cholangiocarcinoma patients have IDH1 mutations in their tumors.

The company explained in a statement that while the overall survival endpoint did not reach statistical significance, there was as a "consistent trend" toward improved survival for patients in the ivosidenib arm. Around 70 percent of patients in the placebo arm crossed over to the ivosidenib arm, which also may have confounded the survival analysis, the company said.

"The data from the ClarIDHy Phase III study show that treatment with Tibsovo has the potential to lengthen time to disease progression and have a clinically meaningful impact on life expectancy for patients with IDH1-mutant cholangiocarcinoma," Agios Chief Medical Officer Chris Bowden said in a statement. "We will collaborate closely with regulators to advance this potential new oral, targeted treatment option for patients."

The company will conduct a full analysis of the ClarIDHy trial data and present it at a future meeting. Ivosidenib is already approved in the US for IDH1-mutated acute myeloid leukemia.