Larimar announces 25 mg, 50 mg data from OL study of nomlabofusp

Larimar Therapeutics (LRMR) announced 25 mg and 50 mg data from the ongoing long-term open label study evaluating daily subcutaneous injections of nomlabofusp self-administered or administered by a caregiver in participants with Friedreich’s ataxia , a rare, progressive, and systemic disease with neurologic deterioration. The Company also provided a nomlabofusp development program update. The OL study is evaluating the safety and tolerability, pharmacokinetics, and FXN levels in skin and buccal cells, along with exploratory pharmacodynamic markers and clinical outcomes following long-term subcutaneous administration of nomlabofusp. Participants were initially administered 25 mg of nomlabofusp daily. The dose was increased to 50 mg in the fourth quarter of 2024, with all newly enrolled patients receiving the 50 mg dose since November of 2024. Participants who completed treatment in a Phase 1 or Phase 2 study evaluating nomlabofusp were the first group of eligible patients to screen for the OL study. The OL study protocol has now been amended to include adolescent and adult patients who have not participated in a prior nomlabofusp study. As of August 27, 2025, 39 participants in the OL study had received at least one dose of nomlabofusp and 25 participants were receiving daily dosing of nomlabofusp for up to 527 days. This includes the time from the initial dose of 25 or 50 mg to the last dose of nomlabofusp prior to the data cut off. Among the study participants, approximately 50% were non-ambulatory at baseline.In participants receiving long term continuous treatment, including 14 participants on nomlabofusp for at least 6 months, 8 of whom continue to be on nomlabofusp for over 1 year, daily administration of nomlabofusp was generally well-tolerated. Most common adverse events continue to be local injection site reactions that were mild to moderate and did not lead to any participant withdrawal from the study. 65 patients have received at least one dose of nomlabofusp in 4 completed studies and the ongoing OL study. Seven OL study participants experienced anaphylaxis and were withdrawn from the study.1 Most of the events occurred on the initial day of administration and all occurred within the first 6 weeks of dosing; all participants returned to their usual state of health after receiving standard treatment. Larimar consulted its experts and decided to modify its starting dose regimen. Larimar provided the FDA with a full update on the clinical development program including the safety, FXN, and clinical data in this press release and FDA agreed with our proposal. Trends towards improvement were observed in modified Friedreich Ataxia Rating Scale, FARS-Activities of Daily Living, 9 Hole Peg Test, and Modified Fatigue Impact Scale at 1 year relative to baseline These clinical findings support that FXN increases after treatment with nomlabofusp may lead to a potential clinical benefit across a broad spectrum of patients with FA, including those with advanced disease. Friedreich’s Ataxia Clinical Outcome Measures Study, a longitudinal natural history study, includes patients with confirmed FA diagnosis Based on the range of baseline characteristics of participants in the OL study, Larimar identified patients from the FACOMS dataset with similar characteristics using data recorded over the last 4 years for each patient mFARS has been used as a primary outcome measure in other clinical trials. OL study participants treated for 1 year with nomlabofusp daily demonstrated a median improvement in mFARS score of 2.25 relative to a worsening of 1.00 observed in patients in the FACOMS reference population. Directional improvements in the other three clinical outcomes were also observed in OL study participants, while worsening in these outcomes was observed in the FACOMS reference population.