Larimar Therapeutics, Inc. announced that the U.S. Food and Drug Administration (FDA) has cleared the Company's four-week, placebo-controlled, Phase 2 dose exploration trial of CTI-1601 in patients with Friedreich's ataxia (FA) to proceed to a 50 mg cohort in which participants will be dosed daily for the first 14 days, and then every other day until day 28. In addition, Larimar's open label extension (OLE) trial was also cleared for initiation by the FDA. Participants in the OLE will receive 25 mg of CTI-1601 daily.

CTI-1601 is a novel protein replacement therapy designed to deliver frataxin to the mitochondria of patients with FA who have low levels of frataxin. Larimar received clearance to advance its Phase 2 trial to a 50 mg cohort and initiate its OLE trial following a review by the FDA of Larimar's complete response to its partial clinical hold that included unblinded safety, pharmacokinetic (PK), and pharmacodynamic (PD) data from the Phase 2 trial's completed 25 mg cohort. Data from the completed 25 mg cohort (n = 13) indicated that CTI-1601 was generally well tolerated and showed increases in frataxin (FXN) levels from baseline compared to placebo in all evaluated tissues (skin and buccal cells) at day 14 (the final day of daily dosing in the trial).

Further dose escalation in the Phase 2 and OLE trials and the initiation of additional U.S. clinical trials evaluating CTI-1601 are contingent on FDA review of results from the Phase 2 trial's 50 mg cohort in accordance with a partial clinical hold. Participants who complete treatment in the Phase 2 dose exploration trial, or who previously completed a prior clinical trial of CTI-1601, are eligible to screen for Larimar's OLE trial. Participants in the OLE trial will receive subcutaneous injections of 25 mg of CTI-1601 administered daily.

The trial is expected to begin in first quarter of 2024 with interim data expected in fourth quarter of 2024. CTI-1601 has been granted Orphan Drug (U.S. and Europe), Rare Pediatric Disease (U.S.), Fast Track (U.S.), and PRIME (Europe) designations for FA.