Larimar Therapeutics’ clinical programme investigating nomlabofusp (CTI-1601) for the treatment of a neurodegenerative movement disorder is back on track after the US Food and Administration (FDA) lifted a partial clinical hold.
Larimar is testing nomlabofusp in an open-label extension study for the treatment of patients with Friedreich’s ataxia – a genetic condition that causes progressive nervous system damage and movement impairment.
The FDA lifted the partial clinical hold following a review of Phase II dose exploration data (NCT05579691), according to a 20 May press release by the US company.
The FDA imposed a full clinical hold on the programme back in 2021 due to safety concerns with higher doses of the drug causing deaths in preclinical studies with non-human primates. In 2022, the FDA lifted the full clinical hold but kept a partial clinical hold, limiting trials to the 25mg dose.
Shares in the biotech rose following the FDA’s decision, up 10% when the market opened on 21 May compared to the pre-announcement market close.
Nomlabofusp is a recombinant fusion protein that delivers human frataxin to cells. Patients with Friedreich’s ataxia are not able to make enough of this protein that is thought to play an important role in energy production in mitochondria.
Larimar initially evaluated nomlabofusp at 25mg, dosing the first patient in March this year. After analysing frataxin pharmacodynamics at this dose, the biotech is planning to hike up the drug’s dose up to 50mg, for which it now has FDA clearance.
Larimar’s CEO Carole Ben-Maimon said in a statement that interim data from the open-label extension study is expected in Q4 this year.
The partial clinical hold was a blemish on the record for a drug that garnered multiple FDA awards, including rare paediatric disease designation, fast track designation and orphan drug designation.
Nonetheless, Larimar touted positive results from the original Phase II study in February 2024. Data demonstrated that the nomlabofusp treatment over four weeks led to increases in frataxin levels in the skin and cells that line the cheeks and lips. Patients in the 50mg cohort had frataxin levels 33% higher than the control group’s average after two weeks.
However, one participant in the 25mg cohort reported a severe adverse event for an allergic reaction and withdrew from the trial.
The ongoing open-label extension study will add data on long-term safety and tolerability, pharmacokinetics, and peripheral tissue frataxin levels.
Reata Pharmaceuticals won the race for the first approved therapy for Friedreich’s ataxia in the US, with its Skyclarys (omaveloxolone) receiving FDA approval in February last year. The oral capsules, which likely work by activating a pathway important in oxidative stress response, are approved to treat the disease in patients aged 16 years and above. Biogen assimilated the therapy into its portfolio following the acquisition of Reata in September 2023.
