Agios wins FDA nod for targeted AML drug Tibsovo

A year after its Celgene-partnered drug Idhifa won FDA approval to treat certain patients with relapsed/refractory acute myeloid leukemia, Agios Pharmaceuticals has scored its first FDA nod for a wholly-owned medicine, Tibsovo.

An oral drug to treat r/r AML patients with the IDH1 mutation, Tibsovo won FDA approval based on data from a phase 1/2 study in 174 patients. In the study, Tibsovo demonstrated a complete remission or complete remission with partial hematologic recovery rate of 32.8%. The median duration of those responses was 8.2 months. Additionally, 37.3% of patients who started the trial dependent on red blood cell or platelet transfusions became independent during any 56-day post-baseline period.

About 6% to 10% of AML patients have the IDH1 mutation, according to the biotech. Tibsovo is the only approved drug for patients with the mutation. 

Agios CEO David Schenkein said in a statement that the approval is an "incredibly exciting milestone" for the biotech and for patients "who have been waiting for new treatment options that work radically different than conventional chemotherapy."

According to SunTrust analyst Yatin Suneja, Agios priced the drug at $26,115 per month. He predicts Tibsovo can generate $300 million in the indication at peak. There are about 700 to 1,100 patients with the mutation in the U.S., he wrote in a note.

Agios and Celgene last year won FDA approval for Idhifa, an IDH2 inhibitor the companies partnered on back in 2010. The FDA approved the drug to treat relapsed/refractory AML patients with an IDH2 mutation.

Between 8% and 19% of AML patients have that mutation, according to Celgene. Already, the Idhifa launch is "tracking ahead of expectations," Suneja wrote. With the two approvals, Agios drugs cover about 20% of the AML patient population, according to the analyst.

The FDA approved Tibsovo with a black box warning detailing risks of differentiation syndrome, but Suneja wrote that doctors know how to manage the side effect. He said the warning is "unlikely" to be a barrier to uptake. 

To support the Tibsovo launch, Agios has deployed more than 30 "senior hematology consultants" around the U.S. to communicate the drug's promise, according to Suneja. The drug was approved in conjunction with an Abbott diagnostic for the IDH1 mutation.