New FA drug nomlabofusp on track for US filing in June seeking its approval
Protein replacement therapy now awarded FDA breakthrough status
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Following feedback from the U.S. Food and Drug Administration (FDA), Larimar Therapeutics is on track to soon submit an application seeking accelerated approval — which gets a drug to patients but still requires additional testing — of nomlabofusp, its protein replacement therapy for Friedreich’s ataxia (FA).
Larimar recently met with the FDA as part of its participation in the START (Support for Clinical Trials Advancing Rare Disease Therapeutics) pilot program. The company said the regulatory agency confirmed key aspects of its planned application for nomlabofusp for FA.
The drug developer expects to submit the application in June, according to a company press release. If all goes well, Larimar aims to have nomlabofusp commercially available in the U.S. by the first half of 2027.
“We are pleased to have continued engagement with the FDA on our planned BLA [biologics license application] submission for nomlabofusp and we appreciate FDA’s thorough review of the preliminary clinical data. This regulatory progress supports our BLA readiness seeking accelerated approval and allows us to focus on continued execution,” said Carole Ben-Maimon, MD, president and CEO of Larimar.
The company also announced that the FDA has awarded nomlabofusp breakthrough therapy designation. Such status is given to medicines designed to treat serious diseases that have shown promise in early clinical testing. The designation aims to speed the development of important new therapies.
According to Rusty Clayton, a board-certified pediatric pulmonologist and Larimar’s chief medical officer, “receiving Breakthrough Therapy Designation underscores the FDA’s recognition of the high unmet medical needs and the potential for nomlabofusp to demonstrate a substantial improvement over available therapy on clinically significant endpoints.”
FA is caused by mutations that lead to low levels of the protein frataxin; nomlabofusp aims to deliver a healthy version of this protein to the body’s cells.
Nomlabofusp aims to boost frataxin protein levels in body’s cells
Larimar is planning to seek accelerated approval of the therapy based on data showing it increased frataxin protein levels in skin cells of people with FA in an ongoing open-label study (NCT06447025). In an open-label study, both participants and researchers know the therapy being given.
Recent data from that trial showed all 10 evaluable patients had frataxin protein levels within the range that’s typical for FA carriers — that is, people who carry a disease-causing mutation that they could pass to their biological children, but who do not themselves have FA symptoms. These increases were accompanied by improvements in a range of functional measures. The FDA’s decision to grant breakthrough therapy was based largely on a review of these early data.
“As part of the [breakthrough therapy designation] request, the FDA reviewed preliminary nomlabofusp data demonstrating improvements in [functional measures], as well as decreased fatigue, in the context of increased tissue [frataxin] to levels similar to those observed in asymptomatic carriers with no signs of disease,” Clayton said.
Clayton said the trial results to date are promising.
“We are encouraged by the increasing body of clinical data supporting the potential of nomlabofusp to modify disease progression by targeting the root cause of FA, [frataxin] deficiency,” Clayton said. “We look forward to continued collaboration with the FDA as we proceed toward potential registration.”
Larimar expects to have full data from the open-label study available in the next few months. The company will use those results as a basis for applying for accelerated approval, a type of conditional approval in which the FDA allows a therapy to be brought to market based on early clinical data that it will likely benefit patients.
We are committed to ensuring a robust and comprehensive data package [for the FDA filing] that captures the favorable benefit-risk profile of nomlabofusp and its potential to meaningfully improve outcomes for patients with FA.
Larimar said the FDA’s recent feedback confirmed that the agency is willing to consider increased frataxin protein levels as a basis for accelerated approval. The agency also confirmed its alignment with the analysis approaches Larimar is planning to use to evaluate the study results.
“We are committed to ensuring a robust and comprehensive data package that captures the favorable benefit-risk profile of nomlabofusp and its potential to meaningfully improve outcomes for patients with FA,” Ben-Maimon said.
Accelerated approval decision would require further clinical testing
If the FDA does grant nomlabofusp accelerated approval, Larimar would be required to conduct additional clinical testing aimed at proving the therapy actually does offer clinical benefit to patients, with long-term approval contingent on the results.
The company noted that it has already made plans for a confirmatory Phase 3 trial, which it expects to launch in the coming months in tandem with the application seeking accelerated approval. In its recent feedback, the FDA agreed to key aspects of the Phase 3 trial’s design, including its main goal: showing that the therapy can help improve Upright Stability Score (USS), a measure of balance.
“We continue to plan for a June 2026 BLA submission seeking accelerated approval and are excited to initiate our confirmatory Phase 3 study in the U.S., [the EU], [the] U.K., Canada and Australia,” Ben-Maimon said. “We are proud to have clinical trial applications related to our Phase 3 study currently under review in France and Canada, with submission to U.K. regulatory authorities soon to follow.”
