Kura Oncology and Kyowa Kirin to Present First Ziftomenib-FLT3 Inhibitor Clinical Data at ASH 2026

Kura Oncology details ziftomenib’s clinical progress and safety profile ahead of key ASH presentations.

What the company is saying

Kura Oncology and Kyowa Kirin are highlighting the breadth of ziftomenib’s clinical development, with eight abstracts—including four oral presentations—accepted for the 2026 ASH Annual Meeting. The announcement emphasizes their strategic collaboration to develop and commercialize ziftomenib for acute myeloid leukemia (AML) globally. The companies frame ziftomenib as a potential backbone therapy, citing new data to be presented on combinations with FLT3 inhibitors and other agents, as well as exploratory analyses in additional AML subtypes. Mollie Leoni, M.D., Chief Medical Officer of Kura Oncology, positions the strategy as building clinical evidence across complementary approaches, extending into FLT3 inhibitor combinations. The release provides detailed safety and adverse event data from clinical trials, including rates of differentiation syndrome, QTc interval prolongation, and other serious adverse reactions. The tone is measured and data-driven, with forward-looking statements about ziftomenib’s potential but no overstatement of unproven benefits.

What the data suggests

The announcement provides granular safety data from clinical trials of ziftomenib (KOMZIFTI) in relapsed or refractory NPM1-mutated AML. Differentiation syndrome occurred in 26% of 112 patients, with Grade 3 events in 13% and fatal outcomes in two patients. Across all AML genetic forms, differentiation syndrome was seen in 25% of patients, with four fatal cases among 39 KMT2A-rearranged AML patients. QTc interval prolongation was reported in 12% of patients, Grade 3 in 8%, QTcF > 500 msec in 9%, and an increase from baseline QTcF > 60 msec in 12%. Dose reduction for QTc prolongation was needed in 1% of cases. Fatal adverse reactions occurred in 4% of patients, with serious adverse reactions in 79%. Dosage interruption due to adverse reactions occurred in 54% of patients, dose reduction in 4%, and permanent discontinuation in 21%. The most common (≥20%) adverse reactions included aspartate aminotransferase increased (53%), infection without identified pathogen (52%), potassium decreased (52%), albumin decreased (51%), alanine aminotransferase increased (50%), sodium decreased (49%), creatinine increased (45%), alkaline phosphatase increased (41%), hemorrhage (38%), diarrhea (36%), nausea (35%), fatigue (34%), edema (30%), bacterial infection (28%), musculoskeletal pain (28%), bilirubin increased (27%), potassium increased (26%), differentiation syndrome (26%), pruritus (23%), febrile neutropenia (22%), and transaminases increased (21%). No new efficacy data are disclosed; all upcoming clinical results are scheduled for presentation at ASH. The FDA approval of KOMZIFTI for relapsed or refractory NPM1-mutated AML is a realised milestone, but broader efficacy and safety in other populations remain to be established.

Analysis

The announcement is primarily factual, detailing the acceptance of eight abstracts for presentation at the 2026 ASH Annual Meeting and providing extensive, specific clinical safety and adverse event data for ziftomenib. While several claims are forward-looking—such as the promise of new clinical results and exploratory analyses—these are appropriately framed as upcoming presentations rather than as realised breakthroughs. The only realised, material milestone is the FDA approval of KOMZIFTI for a specific AML population, which is clearly stated. There is no evidence of exaggerated language or narrative inflation; the tone is measured and clinical. No large capital outlay or immediate financial impact is discussed, and the absence of financial metrics is appropriate for a clinical pipeline update. The gap between narrative and evidence is minimal, as the release does not overstate the significance of the upcoming data presentations.

Risk flags

• ●Safety remains a significant concern, with 26% of patients experiencing differentiation syndrome, 13% at Grade 3 severity, and fatal outcomes in both NPM1-mutated and KMT2A-rearranged AML populations. These rates may limit broader adoption or trigger regulatory scrutiny.
• ●Serious adverse reactions occurred in 79% of patients, and permanent discontinuation due to adverse events was required in 21%, indicating a high overall toxicity burden that could impact real-world use and market uptake.
• ●The announcement does not disclose new efficacy data from the upcoming ASH presentations, so claims about ziftomenib’s potential as a backbone therapy remain unsubstantiated until those results are released.
• ●QTc interval prolongation, reported in up to 14% of younger patients and 10% of older patients, introduces additional cardiac safety risk, especially in a population with high comorbidity burden.

Bottom line

Kura Oncology’s update provides a comprehensive look at ziftomenib’s clinical safety profile and pipeline breadth ahead of major data presentations at the 2026 ASH Annual Meeting. The FDA approval for relapsed or refractory NPM1-mutated AML is a meaningful achievement, but the high rates of serious and fatal adverse reactions underscore substantial safety risks. No new efficacy results are disclosed in this release; the true impact of ziftomenib in broader AML populations will depend on the imminent ASH data. Investors should focus on the detailed clinical outcomes to be presented in December, as these will determine whether ziftomenib can expand its role beyond its current narrow approval. The most important takeaway is that while the company’s clinical activity is robust, the safety profile is challenging and the commercial potential remains unproven until further data are available.

Announcement summary

(NASDAQ:KURA) Kura Oncology, Inc. and Kyowa Kirin Co., Ltd announced that eight abstracts related to ziftomenib, including four oral presentations and four posters, have been accepted for presentation at the 2026 American Society of Hematology (ASH) Annual Meeting, scheduled for December 12-15 in New Orleans. The companies are collaborating under a strategic agreement to develop and commercialize ziftomenib for acute myeloid leukemia (AML) worldwide. Presentations will include first clinical results for ziftomenib in combination with FLT3 inhibitors quizartinib and gilteritinib, longer-term frontline data for ziftomenib plus venetoclax and azacitidine, and exploratory analysis of ziftomenib activity in AML subtypes beyond NPM1-mutated and KMT2A-rearranged disease. FLT3 mutations occur in nearly one third of AML patients and about one half of those with an NPM1 mutation, making NPM1/FLT3 co-mutated AML a key population for ziftomenib combination development. Two oral presentations will report preliminary safety and clinical activity from ziftomenib combinations with FLT3 inhibitors: KOMET-007 (ziftomenib plus quizartinib and intensive chemotherapy in newly diagnosed NPM1/FLT3-ITD co-mutated AML) and KOMET-008 (ziftomenib plus gilteritinib in relapsed or refractory NPM1/FLT3 co-mutated AML). A poster from KOMET-007 will provide longer-term follow-up on response durability, overall survival, and safety with ziftomenib plus venetoclax and azacitidine in newly diagnosed NPM1-mutated AML patients ineligible for intensive chemotherapy, supporting the ongoing global Phase 3 KOMET-017 study. An exploratory analysis from KOMET-001 will describe ziftomenib monotherapy activity in R/R AML patients without NPM1 mutations or KMT2A rearrangements but with other genomic alterations associated with MEIS1 expression. Two additional oral presentations will feature ziftomenib: one reporting initial results from the PedAL Phase 1 ITCC-101/APAL2020K trial in pediatric R/R acute leukemia, and another presenting preclinical findings from menin-associated leukemia subsets. All eight abstracts are available on the ASH website. KOMZIFTI (ziftomenib) is an FDA-approved, once-daily oral menin inhibitor for adults with relapsed or refractory NPM1-mutated AML with no satisfactory alternative treatment options. In clinical trials, differentiation syndrome (DS) occurred in 29 (26%) of 112 patients with R/R AML with an NPM1 mutation treated with KOMZIFTI at the recommended dosage; DS was Grade 3 in 13% and fatal in two patients. In all patients with any genetic form of AML treated with KOMZIFTI monotherapy, DS occurred in 25% of patients. Four fatal DS cases occurred out of 39 patients with KMT2A-rearranged AML treated with KOMZIFTI. In the 112 patients with an NPM1 mutation, DS was observed as early as 3 days and up to 46 days after initiation, with a median onset of 15 days. Treatment was interrupted and resumed in 15 (13%) patients, and permanently discontinued in 2 (2%) patients. QTc interval prolongation was reported as an adverse reaction in 12% of 112 patients, with Grade 3 in 8%, QTcF > 500 msec in 9%, and increase from baseline QTcF > 60 msec in 12%. Dose reduction due to QTc prolongation was required for 1% of patients. QTc prolongation occurred in 14% of patients under 65 and 10% of those 65 or older. Fatal adverse reactions occurred in 4 (4%) patients, including 2 with differentiation syndrome, 1 with infection, and 1 with sudden death. Serious adverse reactions were reported in 79% of patients. Serious adverse reactions in ≥5% included infection without identified pathogen (29%), febrile neutropenia (18%), bacterial infection (16%), differentiation syndrome (16%), and dyspnea (6%). Dosage interruption due to adverse reaction occurred in 54% of patients. Adverse reactions requiring dose interruption in ≥2% included infection without identified pathogen (15%), differentiation syndrome (13%), febrile neutropenia (5%), pyrexia (4%), electrocardiogram QT prolonged (4%), leukocytosis (4%), bacterial infection (3%), cardiac failure (2%), cholecystitis (2%), diarrhea (2%), pruritus (2%), and thrombosis (2%). Dose reduction due to adverse reaction occurred in 4% of patients. Permanent discontinuation due to adverse reaction occurred in 21% of patients. Adverse reactions requiring permanent discontinuation in ≥2% were infection without identified pathogen (8%), bacterial infection (4%), cardiac arrest (2%), and differentiation syndrome (2%). Most common (≥20%) adverse reactions, including laboratory abnormalities, were aspartate aminotransferase increased (53%), infection without identified pathogen (52%), potassium decreased (52%), albumin decreased (51%), alanine aminotransferase increased (50%), sodium decreased (49%), creatinine increased (45%), alkaline phosphatase increased (41%), hemorrhage (38%), diarrhea (36%), nausea (35%), fatigue (34%), edema (30%), bacterial infection (28%), musculoskeletal pain (28%), bilirubin increased (27%), potassium increased (26%), differentiation syndrome (26%), pruritus (23%), febrile neutropenia (22%), and transaminases increased (21%).

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