Kura Oncology, Inc.: Kura Oncology Reports Preclinical Data Supporting Opportunity for Ziftomenib in Treatment of Gastrointestinal Stromal Tumors (GIST)

- Combination of ziftomenib and imatinib shows robust and durable antitumor activity in imatinib-sensitive (1L) and imatinib-resistant (2L/3L) GIST models -

- Proof-of-concept study of ziftomenib plus imatinib in patients with advanced GIST after imatinib failure to begin in 1H 2025 -

SAN DIEGO, Oct. 24, 2024 (GLOBE NEWSWIRE) -- Kura Oncology, Inc. (Nasdaq: KURA), a clinical-stage biopharmaceutical company committed to realizing the promise of precision medicines for the treatment of cancer, today reported preclinical data supporting the development of the Company's menin inhibitor, ziftomenib, for the treatment of advanced gastrointestinal stromal tumors (GIST).

The new findings are being presented at the 36^th EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics in Barcelona. A copy of the poster, entitled "Menin Inhibitor Ziftomenib Synergizes with Imatinib in Tyrosine Kinase Inhibitor (TKI)-Resistant Gastrointestinal Stromal Tumor Models," is available in the Posters and Presentations section on Kura's website.

"Kura has generated a substantial body of preclinical data that support potential for ziftomenib in combination with KIT inhibitors for the treatment of patients with advanced GIST," said Francis Burrows, Ph.D., Senior Vice President, Translational Research. "Our results indicate that the combination of ziftomenib and imatinib acts via a synthetic lethal mechanism through which ziftomenib targets an epigenetic vulnerability of GIST tumors, creating potent synergy even with KIT inhibitors that are otherwise inactive as monotherapy. Indeed, the activity of ziftomenib appears to be agnostic to the mutational status of KIT in GIST, suggesting an opportunity to explore the combination for all patients, even in the frontline setting."

The combination of ziftomenib and imatinib unexpectedly showed robust and durable antitumor activity in both imatinib-sensitive and imatinib-resistant GIST patient-derived xenograft models, and in all cases was significantly superior to imatinib monotherapy. Mechanistically, the data reveal a KIT-dependent mechanism, with ziftomenib and imatinib combining to sharply reduce KIT expression and/or activity, effectively silencing both the ERK and AKT/mTOR signaling pathways and driving robust cell cycle arrest and apoptosis.

Given that imatinib is well established as the frontline standard of care in patients with GIST, and that generic versions are available, imatinib represents a promising combination partner for ziftomenib.

In August 2024, Kura announced clearance by the U.S. Food and Drug Administration (FDA) of the Investigational New Drug (IND) application for ziftomenib for the treatment of advanced GIST. The Company is now preparing to initiate a proof-of-concept study evaluating ziftomenib and imatinib in patients with advanced GIST after imatinib failure in the first half of 2025. For more information regarding the study, please visit www.clinicaltrials.gov (identifier: NCT06026410).

About GIST

Gastrointestinal stromal tumors (GIST) are the most common form of sarcoma, characterized as KIT-dependent solid tumors. Despite the successful disease control achieved with imatinib in advanced GIST patients, most patients eventually progress due to acquired secondary KIT mutations. TKIs such as sunitinib can target imatinib-resistant genotypes and are approved in later lines, but response rates and long-term outcomes are modest, so new therapeutic options are needed. Previously published data show that the menin-MLL complex regulates KIT expression in GIST cells, and menin inhibitors display additive therapeutic activity in combination with imatinib in imatinib-sensitive GIST models¹.

About Ziftomenib

Ziftomenib is a potent, selective and oral menin inhibitor currently in development for the treatment of genetically defined AML patients with high unmet need. In April 2024, ziftomenib received Breakthrough Therapy Designation (BTD) by the FDA for the treatment of relapsed/refractory (R/R) NPM1-mutant acute myeloid leukemia (AML) based on data from Kura's ongoing KOMET-001 clinical trial. Additional information about clinical trials for ziftomenib can be found at kuraoncology.com/clinical-trials/ziftomenib.

About Kura Oncology

Kura Oncology is a clinical-stage biopharmaceutical company committed to realizing the promise of precision medicines for the treatment of cancer. The Company's pipeline consists of small molecule drug candidates that target cancer signaling pathways. Ziftomenib, a once-daily, oral drug candidate targeting the menin-KMT2A protein-protein interaction, has received BTD for the treatment of R/R NPM1-mutant AML. Kura has completed enrollment in a Phase 2 registration-directed trial of ziftomenib in R/R NPM1-mutant AML (KOMET-001). The Company is also conducting a series of clinical trials to evaluate ziftomenib in combination with current standards of care in newly diagnosed and R/R NPM1-mutant and KMT2A-rearranged AML. Kura is evaluating KO-2806, a next-generation farnesyl transferase inhibitor (FTI), in a Phase 1 dose-escalation trial as a monotherapy and in combination with targeted therapies (FIT-001). Tipifarnib, a potent and selective FTI, is currently in a Phase 1/2 trial in combination with alpelisib for patients with PIK3CA-dependent head and neck squamous cell carcinoma (KURRENT-HN). For additional information, please visit Kura's website at www.kuraoncology.com and follow us on X and LinkedIn.

Forward-Looking Statements

This news release contains certain forward-looking statements that involve risks and uncertainties that could cause actual results to be materially different from historical results or from any future results expressed or implied by such forward-looking statements. Such forward-looking statements include statements regarding, among other things, the efficacy, safety and therapeutic potential of ziftomenib, potential benefits of combining ziftomenib with appropriate standards of care, and progress and expected timing of the ziftomenib program and clinical trials. Factors that may cause actual results to differ materially include the risk that compounds that appeared promising in early research or clinical trials do not demonstrate safety and/or efficacy in later preclinical studies or clinical trials, the risk that Kura may not obtain approval to market its product candidates, uncertainties associated with performing clinical trials, regulatory filings, applications and other interactions with regulatory bodies, risks associated with reliance on third parties to successfully conduct clinical trials, the risks associated with reliance on outside financing to meet capital requirements, and other risks associated with the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics, and in the endeavor of building a business around such drugs. You are urged to consider statements that include the words "may," "will," "would," "could," "should," "believes," "estimates," "projects," "promise," "potential," "expects," "plans," "anticipates," "intends," "continues," "designed," "goal," or the negative of those words or other comparable words to be uncertain and forward-looking. For a further list and description of the risks and uncertainties the Company faces, please refer to the Company's periodic and other filings with the Securities and Exchange Commission (SEC), including the Company's Form 10-Q for the quarter ended June 30, 2024 filed with the SEC on August 8, 2024, which are available at www.sec.gov. Such forward-looking statements are current only as of the date they are made, and Kura assumes no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

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¹ Hemming ML et al., Cancer Discov. 2022;12:1804-1823.