The US Food and Drug Administration (FDA) cleared a phase 2 dose exploration clinical trial of CTI-1601, a potential new treatment for Friedreich ataxia (FA), to proceed to a 50 mg cohort.

In this part of the trial, participants will be given the trial drug every day for the first 14 days, and then every other day until day 28.

Read more about FA diagnosis

The FDA also cleared the open-label extension (OLE) part of the trial, in which participants will be given 25 mg of CTI-1601 every day.

“Gaining clearance to advance to a 50 mg cohort in our phase 2 trial and initiate the OLE trial are crucial steps in CTI-1601’s development,” said Carole Ben-Maimon, MD, the president and chief executive officer of Larimar Therapeutics, the developers of the treatment, in a press release. “We now look forward to data from our Phase 2 trial’s 50 mg cohort in the first half of 2024, which will help us further characterize the safety and [pharmacokinetic] profiles of CTI-1601.”

The phase 2 trial is a placebo-controlled trial lasting 4 weeks, the aim of which is to further characterize the safety, pharmacokinetics, and pharmacodynamics of CTI-1601.

Its 25 mg cohort of 13 patients with FA, which is already complete, showed that CTI-1601 was generally well tolerated and led to an increase in frataxin levels in the skin and buccal cells of patients at day 14 from baseline compared to placebo.

The OLE trial is designed for patients with FA who have previously been treated with CTI-1601. Its objective is to evaluate the safety, tolerability, and pharmacokinetics of long-term subcutaneous CTI-1601 as well as measures of frataxin levels and other pharmacodynamic markers in peripheral tissues.

CTI-1601 is a protein replacement therapy that aims to deliver frataxin to the mitochondria. Frataxin is a mitochondrial protein that plays a role in iron homeostasis. Its levels are decreased in FA.


Larimar Therapeutics receives FDA clearance to proceed to 50 mg cohort in CTI-1601’s phase 2 Friedreich’s ataxia trial and to initiate open label extension trial. News release. Larimar Therapeutics; July 25, 2023.

A double-blind, placebo-controlled, dose exploration study of CTI-1601 in adult subjects with Friedreich’s ataxia. US National Library of Medicine. Updated October 14, 2022, Accessed August 9, 2023.