US-based Larimar Therapeutics has reported positive top-line data from a Phase II exploratory trial of Friedreich’s ataxia drug, nomlabofusp (CTI-1601).

Larimar Therapeutics’s CEO Dr Carole Ben-Maimon stated that the company plans to start a confirmatory trial for the drug, intending to file a biologics licence application (BLA) with the US Food and Drug Administration (FDA) in H2 2025.

The placebo-controlled Phase II trial (NCT05579691) enrolled 28 participants with Friedreich’s ataxia, a rare genetic, progressive, neurodegenerative movement disorder. Nomlabofusp demonstrated dose-dependent increases in frataxin (FXN) levels in all evaluated tissues (skin and buccal cells) after daily dosing for 14 days, followed by every other day dosing until day 28 in the 25mg and 50mg cohorts.

The participants in the 50mg cohort, with quantifiable baseline FXN skin levels, showed FXN levels in skin cells greater than 33% of the average level found in healthy volunteers after 14 days of treatment. Friedreich’s ataxia is associated with low levels of functional FXN, and it has been theorised that restoration of FXN level can improve patients' symptoms. Nomlabofusp is a protein replacement therapy designed to deliver frataxin protein to the cells of people with Friedreich’s ataxia.

The drug was generally well tolerated. One participant in the 25mg cohort reported a severe adverse event for an allergic reaction. While the reaction resolved with standard treatment, the participant withdrew from the trial.

In January, Larimar initiated an open-label extension study of nomlabofusp, with patient dosing planned to start in Q4 this year. The participants will self-administer a daily dose of 25mg of subcutaneous nomlabofusp. The trial aims to inform the long-term safety and self-administration of nomlabofusp following daily subcutaneous administration. The interim results from the trial are expected in Q4 2024.

Larimar aims to pursue accelerated approval for nomlabofusp. To that end, the company plans to use tissue FXN levels as a novel surrogate endpoint and stated that the FDA acknowledged that frataxin deficiency appears to be critical to the pathogenic mechanism of Friedreich’s ataxia. Larimar said it is having ongoing discussions with the agency to support accelerated approval of the therapy.

The Friedreich’s ataxia treatment landscape has changed dramatically in the past year. The first ever therapy for the disease, Reata Pharmaceuticals Skyclarys (omaveloxolone), was approved to treat Friedreich’s ataxia in patients aged 16 years and above by the FDA in March 2023. The therapy is now part of Biogen’s portfolio following the acquisition of Reata in September 2023.