Agios’ data on leukemia drug ivosidenib doesn’t excite investors

Myeloblasts with Auer rods seen in acute myeloid leukemia
The company highlighted combo data for ivosidenib and Idhifa with chemo in front-line AML.

Along with data that will support the filing of IDH1 inhibitor ivosidenib in refractory acute myeloid leukemia (AML), Agios is also readying data on a first-line combination for presentation at next month’s American Society of Hematology (ASH) conference.

Agios has been saying for months that it is on track to file ivosidenib for refractory AML before the end of the year and has provided a peek at the data it will use to support the application at ASH in the form of an abstract of a phase 1 dose-escalation trial of the drug.

The company is also presenting phase 1 data from combinations of ivosidenib and its IDH2 inhibitor Idhifa (enasidenib)—licensed to Celgene and approved in August—alongside current first-line therapies for AML that could unlock a much larger market for the two drugs.

“Early data from these phase 1 trials reinforce ongoing efforts at Agios and Celgene to advance the IDH inhibitors into the newly diagnosed setting,” said Agios CEO David Schenkein on the biotech’s third-quarter results call yesterday.

The company was upbeat about all the results on the call, but investors seemed unswayed as shares in the company fell almost 4% on the announcement on high-volume trading, bucking the general trend among other biotechs trumpeting their ASH data.

In the trial involving refractory AML patients with IDH1 mutations, which account for around 6% to 10% of all AML cases, Agios’ drug showed a complete remission rate including complete hematologic recovery (CR+ CRh+) of 21.6%, with another 8.8% seeing a complete remission with partial hematologic recovery. The data "was as compelling as the data we’ve shown on our lead program, which was given full approval by the FDA this year," said a spokesperson.

Agios will provide additional data at ASH on secondary measures such as transfusion independence and overall survival, said Chief Medical Officer Chris Bowden, M.D.

The results in newly diagnosed AML patients with IDH1 or 2 mutations—a group which collectively accounts for around 15% to 20% of all AML patients—revealed that adding ivosidenib or Idhifa to induction chemotherapy was generally well-tolerated. The overall response rate for ivosidenib in primary AML patients was 86% and 44% among patients whose AML was secondary to another blood-related disorder such as myelodysplastic syndrome. For Idhifa those response rates were 67% and 58%, respectively.

“The early data is encouraging and validate our existing and planned late stage efforts in the front-line setting,” said Bowden, who suggested that the company should be able to give more information on the path toward regulatory approval in front-line AML at an investor event during the ASH meeting on Dec. 11.

Ivosidenib was once part of the alliance between Agios and Celgene, but last year Celgene handed back ex-U.S. rights as part of a rerolling of the original 2010 pact between the two firms.