TOKYO & SAN DIEGO, April 24, 2026

Kyowa Kirin and Kura Oncology have announced a major clinical milestone with the initiation of a Japanese Phase 2 registrational trial evaluating ziftomenib, an oral menin inhibitor, for patients with relapsed or refractory (R/R) NPM1-mutated acute myeloid leukemia (AML). This development represents a critical step toward expanding global access to precision oncology therapies, particularly for patients facing limited treatment options. The trial, which has already dosed its first patient, is expected to support a future regulatory filing in Japan, highlighting the growing momentum behind targeted therapies in hematologic malignancies.

Advancing Targeted Therapy for High-Unmet AML Needs

The Phase 2 study is a multicenter, open-label, single-arm clinical trial designed to assess the efficacy and safety of ziftomenib in adult patients with NPM1-mutated AML, a subtype that accounts for approximately 30% of AML cases. Patients with relapsed or refractory disease often face poor prognosis and limited therapeutic options, making the development of novel targeted treatments a top priority in oncology research.

The primary endpoint of the study focuses on composite complete remission rates, including complete remission (CR) and complete remission with partial hematologic recovery (CRh), which are key indicators of treatment success. Ziftomenib has already demonstrated a favorable safety and efficacy profile in previous trials and received U.S. FDA approval in November 2025 under the brand name KOMZIFTI™, further reinforcing its potential as a next-generation therapy for AML patients worldwide.

Strategic Collaboration Driving Global Development

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The collaboration between Kyowa Kirin and Kura Oncology reflects a strategic global partnership aimed at accelerating innovation in cancer treatment. Under their agreement, Kyowa Kirin leads development and commercialization outside the United States, while Kura Oncology oversees U.S.-based clinical and regulatory efforts, ensuring a coordinated global development strategy.

This partnership leverages the strengths of both organizations to bring cutting-edge precision medicines to patients faster and more efficiently. According to leadership from both companies, the initiation of this trial underscores their shared commitment to addressing urgent unmet medical needs in hematologic cancers, while also paving the way for broader applications of menin inhibitors across multiple genetic mutations, including KMT2A and FLT3.

Future Outlook for Precision Oncology in AML

Beyond this trial, ziftomenib is being explored in combination therapies and earlier treatment settings, signaling its potential to transform the standard of care for AML. Experts believe that targeting specific genetic mutations such as NPM1 represents a paradigm shift toward precision oncology, enabling more personalized and effective treatment strategies. The initiation of this Japanese trial not only strengthens the global clinical development pathway for ziftomenib but also reinforces the importance of regional regulatory strategies in accelerating patient access.

As the study progresses, successful outcomes could lead to regulatory approval in Japan, expanding treatment availability and offering renewed hope to AML patients who currently have limited therapeutic alternatives. The continued evolution of targeted cancer therapies is expected to redefine treatment landscapes, with ziftomenib emerging as a key contender in next-generation leukemia care.

Source: Kyowa Kirin, Kura Oncology press release