8-K: Larimar Reports Positive Nomlabofusp Data for FA

Larimar Therapeutics announced positive long-term open label study data for nomlabofusp in Friedreich's ataxia, showing increased frataxin levels and clinical improvements, alongside a modified dosing regimen and a Q2 2026 BLA target.

Summary

• Positive 25 mg and 50 mg data from the ongoing long-term open label (OL) study evaluating daily subcutaneous injections of nomlabofusp in participants with Friedreich's ataxia (FA) were announced.
• 65 participants have received at least one dose of nomlabofusp across 4 completed studies and the ongoing OL study, with 39 in the OL study.
• 14 participants in the OL study have been on treatment for at least 6 months, and 8 for over 1 year.
• Skin frataxin (FXN) levels increased with both shortand long-term daily nomlabofusp administration.
• 100% of participants (10/10) with 6-month data achieved skin FXN levels over 50% of median levels in healthy volunteers, which is similar to levels found in asymptomatic carriers.
• Consistent directional improvement was observed across 4 key clinical outcomes (mFARS, FARS-ADL, 9-HPT, MFIS) after 1 year of nomlabofusp treatment, suggesting potential clinical benefit relative to a worsening in a FACOMS natural history study reference population.
• Specifically, OL study participants treated for 1 year demonstrated a median improvement in mFARS score of 2.25, compared to a median worsening of 1.00 observed in the FACOMS reference population.
• A Biologics License Application (BLA) submission seeking accelerated approval is targeted for Q2 2026.
• The company modified its starting dose regimen for nomlabofusp following two recent cases of anaphylaxis, and the FDA agreed with this approach.

Sentiment

Score: 8

Explanation: The positive clinical data, particularly the increase in frataxin levels to asymptomatic carrier levels and the observed clinical improvements relative to natural disease progression, are highly encouraging. The FDA's agreement with the modified dosing regimen and the BLA strategy for accelerated approval provides a clear path forward. While the anaphylaxis events are a concern, the company's proactive mitigation and FDA's acceptance temper the negative impact, indicating manageable risks for a rare, severe disease with high unmet need.

Positives

• 100% of participants with 6-month data achieved skin FXN levels over 50% of median healthy volunteer levels, indicating successful frataxin replacement.
• Consistent directional improvement across 4 key clinical outcomes (mFARS, FARS-ADL, 9-HPT, MFIS) after 1 year of treatment, suggesting potential clinical benefit.
• Median mFARS score improved by 2.25 in OL study participants after 1 year, contrasting with a median worsening of 1.00 observed in the FACOMS natural history reference population.
• The FDA agreed with the modified starting dose regimen and the overall clinical development program, including the BLA strategy for accelerated approval.
• BLA submission seeking accelerated approval is targeted for Q2 2026, indicating a clear and relatively near-term path to market.
• The long-term open label study was expanded to include adolescents and adults not previously in nomlabofusp studies, broadening the patient population.
• Pharmacokinetic profile in adolescents (12-17 years) was similar to adults, supporting broader applicability.
• The company has $203.6 million in pro forma cash and investments as of June 30, 2025, providing a projected cash runway into Q4 2026.

Negatives

• 7 participants in the OL study experienced anaphylaxis, leading to withdrawal from the study.
• Most anaphylaxis events occurred on the initial day of administration, and all occurred within the first 6 weeks of dosing.
• The need to modify the starting dose regimen due to anaphylaxis events indicates a safety concern that required mitigation.

Risks

• Anaphylaxis and Allergic Reactions: Allergic reactions, including anaphylaxis, are a known risk associated with nomlabofusp, with 7 participants experiencing anaphylaxis in the OL study. While a modified dosing regimen has been implemented and agreed upon by the FDA, the risk of such events remains.
• Clinical Trial Outcomes: Preliminary clinical trial results may differ from final results, and earlier non-clinical and clinical data may not be predictive of the results or success of later clinical trials.
• Regulatory Approval: The FDA may not ultimately agree with the nomlabofusp development strategy or grant accelerated approval, despite current agreement.
• Manufacturing and Supply Chain: The ability to optimize and scale nomlabofusp's manufacturing process and ensure commercial supply, including successful process performance qualification (PPQ), is crucial.
• Patient Recruitment: Delays in patient recruitment, including as a result of changes in clinical protocols and adverse events, could impact timelines.
• Competition: The only treatment currently approved for FA does not address frataxin deficiency, but future competitive therapies could emerge.
• Capital Requirements: The company's ability to raise necessary capital to conduct its product development activities is a continuous risk, despite the current cash runway.

Future Outlook

The company targets a Biologics License Application (BLA) submission seeking accelerated approval for nomlabofusp in Q2 2026, with a U.S. launch targeted for early 2027. A global Phase 3 double-blind placebo-controlled study is being prepared, with sites being qualified in the U.S., Europe, U.K., Canada, and Australia. The open label study protocol has been amended to include adolescent and adult patients not previously in nomlabofusp studies, and there are plans to enroll children aged 2-11 years directly into the OL study in the future. Process performance qualification (PPQ) on commercial scale drug substance is planned for Q4 2025.

Management Comments

• "We are excited to announce the consistent directional improvements across 4 key clinical outcomes observed in the OL study relative to a Friedrichs Ataxia Clinical Outcomes Measure Study (FACOMS) reference population and the observed increase in skin frataxin (FXN) levels. These new data, as well as the improvement in abnormal lipid profiles observed in prior completed studies, provide support that nomlabofusp increases FXN in patients with FA and that the strategy of FXN replacement has the potential to result in a clinical benefit. Importantly, achieving tissue FXN levels equivalent to more than 50% of those found in healthy volunteers means participants are at levels found in asymptomatic carriers who do not develop the disease." Carole Ben-Maimon, MD, President and Chief Executive Officer of Larimar.
• "The changes observed in skin FXN levels, lipid profiles, and clinical outcomes after nomlabofusp administration across diverse participants with FA – including individuals with advanced disease – are all directionally consistent and suggest a potential treatment effect. Allergic reactions, including anaphylaxis, are a known risk associated with nomlabofusp, similar to many other approved therapies, particularly proteins. To date, all anaphylaxis events have occurred within the first 6 weeks of nomlabofusp administration. In this rare neurodegenerative disease with limited therapeutic options, patients with FA continue to express interest in having access to new potentially disease modifying agents." Dr. Rusty Clayton, Chief Medical Officer of Larimar.
• "FA is a relentlessly progressive disease that is life-altering and can be life-shortening. Treatment approaches, like nomlabofusp, that target the root cause of FA by FXN supplementation are of great interest to the FA community. We are encouraged by the increases in FXN protein and improved clinical outcomes relative to the FACOMS reference population observed in the individuals who have maintained nomlabofusp therapy. FA patients and their families are informed and engaged. They understand that therapies come with side effects and risks that must be evaluated in the context of potential benefit. We appreciate Larimar’s commitment to patient safety and their regular communications and updates on study outcomes." Jennifer Farmer, Chief Executive Officer of the Friedreich’s Ataxia Research Alliance (FARA).

Industry Context

Friedreich's ataxia (FA) is a rare, progressive, and systemic neurodegenerative disease affecting approximately 20,000 patients globally, with about 5,000 in the U.S. It is characterized by a genetic defect leading to lowered frataxin (FXN) levels, causing symptoms like unsteady posture, frequent falling, and eventual wheelchair confinement, with a life expectancy of 30-50 years. There is a significant unmet medical need, as the only currently approved treatment for FA does not address the underlying frataxin deficiency. Nomlabofusp is positioned as the first potential disease-modifying therapy designed to systemically address this root cause by delivering additional frataxin. The observed increases in FXN levels to those found in asymptomatic carriers and consistent directional improvements in clinical outcomes are highly significant in this context.

Comparison to Industry Standards

• Nomlabofusp's observed median improvement in mFARS score of 2.25 after 1 year in the OL study compares favorably to a median worsening of 1.00 observed in patients from the Friedreich's Ataxia Clinical Outcome Measures Study (FACOMS) natural history reference population (N=185). This suggests a potential clinical benefit relative to the natural progression of the disease.
• Achieving skin FXN levels over 50% of median levels in healthy volunteers, similar to asymptomatic carriers, is a significant benchmark, as asymptomatic carriers do not develop the disease. This level of FXN replacement is a strong indicator of therapeutic potential.
• The current landscape for FA treatment is limited, with only one approved therapy that does not address the underlying frataxin deficiency. Nomlabofusp, by targeting FXN supplementation, aims to be the first disease-modifying therapy, setting a new standard if approved.
• The company's engagement with the FDA through the START pilot program and the FDA's agreement with the modified dosing regimen and BLA strategy indicate a collaborative and potentially expedited regulatory pathway, which is a positive sign in the biotech industry for rare disease therapies.

Stakeholder Impact

• Shareholders: Potential for significant value appreciation due to positive clinical data, clear regulatory pathway for accelerated approval, and strong cash position. The successful development of a first-in-class disease-modifying therapy for a rare disease could lead to substantial market opportunities.
• Patients with Friedreich's Ataxia: Offers hope for a new, potentially disease-modifying treatment that addresses the root cause of their progressive and life-altering condition, where current options are limited. The expansion of the OL study to include more patient groups and the planned global Phase 3 study indicate broader access in the future.
• Caregivers: Provides a potential new therapeutic option for managing the disease, which could improve the quality of life for patients and reduce the burden on caregivers.
• Regulatory Authorities (FDA, EMA, MHRA): The company's engagement through programs like START and the FDA's agreement on the development strategy demonstrate a collaborative approach to bringing new therapies to market for unmet medical needs.
• Employees: Positive clinical and regulatory progress can boost morale and provide job security, as the company moves closer to commercialization.

Next Steps

• Implement the new modified dosing regimen in the open label study in Q4 2025.
• Conduct Process Performance Qualification (PPQ) on commercial scale drug substance in Q4 2025.
• Continue enrolling participants on the new starting dose regimen in the OL study, including adolescents and those new to nomlabofusp.
• Plan to enroll children (2-11 years of age) directly into the OL study in the future.
• Initiate the global Phase 3 double-blind placebo-controlled study, with sites currently being qualified in the U.S., Europe, U.K., Canada, and Australia.
• Submit a Biologics License Application (BLA) seeking accelerated approval in Q2 2026.
• Target U.S. launch for early 2027.

Key Dates

Recommendation

The filing presents compelling positive data for nomlabofusp, demonstrating significant increases in frataxin levels to a therapeutically relevant range (similar to asymptomatic carriers) and consistent directional improvements across multiple key clinical outcomes relative to natural disease progression in Friedreich's ataxia. The FDA's agreement with the modified dosing regimen and the strategy for accelerated approval, targeting a BLA submission in Q2 2026 and a U.S. launch in early 2027, de-risks the regulatory pathway considerably. Despite the reported anaphylaxis events, the company's proactive mitigation and the FDA's acceptance suggest these are manageable risks in the context of a severe rare disease with high unmet medical need. The strong cash position provides runway into Q4 2026, supporting ongoing development. This combination of strong clinical efficacy signals, a clear and expedited regulatory path, and financial stability positions Larimar Therapeutics for significant upside potential as it advances towards commercialization of a potential first-in-class disease-modifying therapy.

Keywords

Friedreich's ataxia, nomlabofusp, CTI-1601, frataxin, FXN, rare disease, biotechnology, clinical trial, open label study, BLA, accelerated approval, anaphylaxis, mFARS, FACOMS, neurodegenerative