First-patient dosing anticipated in the third quarter of 2026 in a U.S. Phase 1 study of a first-in-class dual PI3K/EGFR inhibitor

MINNEAPOLIS, May 19, 2026 /PRNewswire/ — MEKanistic Therapeutics, a biotechnology company developing first-in-class precision medicines designed to overcome cancer resistance mechanisms, today announced that the U.S. Food and Drug Administration has cleared the Investigational New Drug application for MTX-531, the company’s lead oncology candidate.

With the IND now in effect, MEKanistic may proceed with its planned Phase 1 clinical study of MTX-531, subject to standard study start-up activities.

MTX-531 is a potential first-in-class small molecule designed to selectively inhibit PI3K and EGFR, two signaling pathways implicated in tumor growth, survival and adaptive resistance.

“IND clearance marks an important milestone for MEKanistic and advances MTX-531 into the clinic,” said Danny Cunagin, chief executive officer of MEKanistic Therapeutics. “We believe MTX-531’s differentiated dual-targeting approach has the potential to address meaningful unmet needs in oncology, provide new options for cancer patients and support a new treatment approach for hard-to-treat cancers.”

The Phase 1 study will evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary anti-tumor activity of MTX-531 in patients with advanced solid tumors characterized by dysregulated EGFR and/or PI3K signaling, including head and neck and endometrial cancers and other tumor types in which these pathways are implicated. The study will include dose-escalation with expansion cohorts at multiple U.S. sites, with first-patient dosing anticipated in the third quarter of 2026.

Preclinical findings published in Nature Cancer in 2024 demonstrated potent inhibition of EGFR and PI3K, durable tumor regressions and a differentiated tolerability profile. IND-enabling toxicology studies were supported through the National Cancer Institute’s Experimental Therapeutics, or NExT, Program.

About MTX-531

MTX-531 is a dual inhibitor of PI3K and EGFR designed to block key signaling pathways involved in tumor progression and adaptive resistance.

About MEKanistic Therapeutics

MEKanistic Therapeutics is a privately held biotechnology company developing innovative kinase inhibitors for cancer.

Forward-Looking Statements

This press release contains forward-looking statements regarding MTX-531, including the planned Phase 1 study and anticipated timing. Actual results may differ materially due to risks and uncertainties.

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SOURCE MEKanistic Therapeutics, Inc.