FDA Grants Fast Track Status to MT-125 in Glioblastoma

The FDA has given fast track designation to MT-125, a first-in-class dual small-molecule inhibitor, for the treatment of glioblastoma.¹

The FDA fast track designation recognizes drugs that serve to treat serious conditions and fill unmet needs.² With this designation, Myosin Therapeutics, the sponsor, is eligible for activities intended to facilitate drug development and expedite regulatory review, including more frequent communication with the FDA, eligibility for accelerated approval and priority review if criteria are met, and rolling review of a new drug application.

“Receiving [f]ast [t]rack designation validates our conviction that MT-125 has the potential to offer an entirely novel treatment approach to patients with even the most aggressive forms of glioblastoma,” said Courtney Miller, MD, chief executive officer of Myosin Therapeutics, in a press release.¹ “We are energized by the open communication with the FDA that the [f]ast [t]rack offers because it will ensure we advance MT-125 as quickly as possible with our patient-centered approach.”

Glioblastoma is a highly malignant and the most aggressive form of brain cancer, characterized by poor prognosis and minimal recent progress in treatment approvals.^3,4 MT-125 is a potent, selective, and central nervous system-permeable dual inhibitor that has demonstrated synergy with radiotherapy and oncogenic kinase inhibitors, promising long-term survival benefits, and a feasible safety profile in preclinical models. Employing a novel mechanism of action, the agent is designed to block the invasive activity of nonmuscle myosin II paralogs IIA and IIB while simultaneously enhancing the effect of radiation,³ which forms part of the current standard of care for glioblastoma.

MT-125 previously received FDA orphan drug designation for malignant gliomas including glioblastoma.¹

What are the next steps in development?

MT-125 will be evaluated in the imminent phase 1/2 STAR-GBM trial (NCT07185880), which is designed to evaluate the safety and tolerability, pharmacokinetics, and preliminary efficacy of the agent in combination with standard-of-care radiotherapy (RT).⁴

The objective of the phase 1 dose-escalation portion is to characterize the safety and tolerability of MT-125, to be administered 5 consecutive days per week with 2 days rest during 6 weeks of outpatient RT. Secondary objectives include establishing the maximum tolerated dose and/or recommended phase 2 dose to be used in the dose-expansion phase as well as assessing pharmacokinetics.

Afterwards, the phase 2 randomized dose-expansion study will assess the preliminary efficacy end points of overall response rate, progression-free survival, and overall survival at the established recommended dose.

This first-in-human study has been cleared by the FDA and is projected to launch in November 2025. While not currently recruiting, the study aims to enroll 36 adult patients with newly diagnosed glioblastoma that is histologically or molecularly confirmed IDH wild type and MGMT unmethylated. This subpopulation was selected for investigation as they do not benefit from standard-of-care temozolomide therapy.

REFERENCES:

1. Myosin Therapeutics Receives FDA Fast Track Designation for MT-125 in Glioblastoma. News release. Myosin Therapeutics. October 22, 2025. Accessed October 23, 2025. https://tinyurl.com/55dbpm7t

2. Fast Track. US Food & Drug Administration. Updated August 13, 2024. Accessed October 23, 2025. https://tinyurl.com/ms2695jn

3. Kenchappa RS, Radnai L, Young EJ, et al. MT-125 inhibits non-muscle myosin IIA and IIB and prolongs survival in glioblastoma. Cell. Published online June 1, 2025. doi:https://doi.org/10.1016/j.cell.2025.05.019

4. A Phase 1 Study of the Safety and Tolerability of MT-125 in GBM Patients (STAR-GBM). ClinicalTrials.gov. Updated September 22, 2025. Accessed October 23, 2025. https://clinicaltrials.gov/study/NCT07185880