Kura Oncology and Kyowa Kirin claim to have scored a phase 2 win for their oral leukemia treatment while reassuring analysts about the lack of any hard data to prove it.
Ziftomenib, an oral selective menin inhibitor, was undergoing a trial in patients with relapsed or refractory NPM1-mutant acute myeloid leukemia. The study hit its primary endpoint of demonstrating a statistically significant improvement in complete response (CR) rate as well as partial hematological recovery (CRh).
Kura and Kyowa used the announcement to confirm that they are on track to file a new drug approval application with the FDA in the second quarter of 2025. However, the release didn’t include any data, with the companies only promising to submit their topline findings at “an upcoming medical meeting” in the second quarter.
Analysts at Mizuho said that Kura had pointed to other biotechs who had been similarly coy with their cancer data to justify their decision to withhold more information. The reason for the lack of transparency was “largely due to conference rules,” according to the analysts’ note.
“[The trial] was powered to detect a CR/CRh rate of 20-30% and the company noted safety and tolerability in-line with previous data, all of which reads fine to us (i.e. likely in the "approvable" range),” the analysts said.
The second half of this year will see Kyowa and Kura launch two phase 3 trials for ziftomenib. One of these will see the drug combined with chemotherapy in AML patients with mutations in the NPM1 or KMT2A genes. The other will test ziftomenib along with Venclexta and Vidaza in NPM1 patients who are unfit to receive intensive chemotherapy.
“Even with approved therapies, up to 70% of patients who achieve a first CR will see their AML return within three years,” Kura’s Chief Medical Officer Mollie Leoni, M.D., said in the Feb. 5 release.
“Given this urgent need, we are pleased with the outcome of these FDA interactions and look forward to initiating our phase 3 trials to establish the benefit-risk profile of ziftomenib in both the intensive and non-intensive chemotherapy settings,” Leoni added.
Japan-based Kyowa Kirin fronted $330 million last year and pledged up to $1.1 billion in milestones to get in on the ziftomenib action. The two companies are sharing responsibility for launching various trials in AML and other blood cancers “over the next several years,” with Kura funding the development of ex-U.S. trials until the end of 2028, after which point the biotechs will split the costs.
Kura began 2024 posting fresh phase 1b data suggesting ziftomenib performed best on top of a standard-of-care combo regimen in newly diagnosed patients with specific mutations.