CTI-1601 is an investigational therapy being developed for people with Friedreich’s ataxia (FA). Chondrial Therapeutics, which began work on CTI-1601, has now merged with Zafgen to form a new company, Larimar Therapeutics, which will continue the development of CTI-1601.

The U.S. Food and Drug Administration (FDA) has designated CTI-1601 an orphan drug and rare pediatric disease to support its development, and placed it on fast track, which could allow for priority review should it come up for approval.

How does CTI-1601 work?

Friedreich’s ataxia is a genetic neuromuscular disease caused by a genetic defect that inhibits the expression of the FXN gene. FXN encodes for a protein called frataxin, which is an essential mitochondrial protein. Mitochondria are the energy-producing centers in the cell. Inadequate amounts of the frataxin protein affect the workings of mitochondria, hampering energy production and increasing oxidative stress in cells.

Lack of frataxin eventually leads to symptoms that include loss of coordination, progressive muscle weakness, and diminishing eyesight. Currently, this disease has no approved disease-modifying treatments.

CTI-1601 uses a platform technology that makes use of a carrier protein to deliver the frataxin protein to the mitochondria of patients. Mitochondria then process this carrier-bound frataxin to become mature frataxin, which plays an active role in mitochondrial metabolism. This could restore protein levels, helping mitochondria to carry out their essential work within cells.

Higher mature frataxin protein levels and healthier mitochondria may help to minimize patients’ symptoms and prevent disease progression.

CTI-1601 in clinical trials

A Phase 1 clinical trial (NCT04176991) is testing the safety, tolerability, and early efficacy of single, ascending doses of CTI-1601, given as an under-the-skin injection, against a placebo in adults with Friedreich’s ataxia. Its primary outcome measure is the number of adverse events recorded throughout the study, which runs for about 2.5 months (70 days). Secondary measures include evaluations of its pharmacokinetics (how the body affects a drug) and pharmacodynamics (how a drug affects the body). Patients will give blood samples and cheek swabs at intervals following treatment, which researchers will analyze.

This study, which began dosing in December 2019 but was paused due to the COVID-19 pandemic, may still be recruiting eligible patients at its one New Jersey site; information is available here. Top-line data is expected to be released in the first half of 2021.


Last updated: June 3, 2020


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