LX2006 gene therapy now on FDA fast track for heart disease in FA
Heart problems affect most patients, but no treatments are approved to date
The U.S. Food and Drug Administration (FDA) has put Lexeo Therapeutics’ LX2006, a gene therapy candidate for heart disease in people with Friedreich’s ataxia (FA), on the fast track for development.
The award of fast track status aims to expedite the development and regulatory review of investigational therapies filling unmet medical needs in serious conditions. It makes the company eligible for more frequent meetings and discussions with the FDA. It also may make LX2006 eligible for accelerated FDA approval and priority review.
“FA cardiomyopathy is the leading cause of death among FA patients, and there are currently no approved treatment options,” R. Nolan Townsend, Lexeo’s CEO, said in a company press release.
“The FDA’s fast track designation for LX2006 underscores the significant unmet need for effective treatment options to address the cardiac impact of this debilitating disease,” Townsend said.
FDA fast track status follows orphan drug, rare pediatric disease designations
FA is caused by mutations in the FXN gene resulting in a deficiency of frataxin, a protein needed for the functioning of mitochondria, the cell’s energy production centers. Nerve and muscle cells are particularly affected, leading to ataxia — a loss of muscle control and coordination that’s an FA hallmark.
Heart problems affect most FA patients, among them cardiomyopathy, a condition of the heart muscle that affects its size, thickness, and function. This leads to symptoms such as fatigue, shortness of breath, and a fast or irregular heartbeat.
LX2006 uses a modified and harmless adeno-associated virus to deliver a functional copy of the gene coding for frataxin (FXN) to the heart. This intends to promote frataxin production and normal mitochondrial function in the heart muscle. Designed as a one-time treatment, the experimental gene therapy is delivered via an intravenous, or into-the-vein, infusion.
The therapy is being tested in the Phase 1/2 SUNRISE-FA clinical trial (NCT05445323). That study is assessing the safety, tolerability, and preliminary efficacy of LX2006 in people with FA-related cardiomyopathy, initially for one year. The trial is recruiting eligible patients, ages 18 to 50, at sites in the U.S. and Canada.
We believe today’s fast track designation, along with the previously announced rare pediatric disease and orphan drug designations granted to LX2006, will allow for enhanced regulatory interactions and the potential for this life-improving therapy to reach FA patients more quickly.
Initial data from the first group of participants indicated the therapy was well tolerated, with no unexpected safety concerns or toxicity.
In SUNRISE, LX2006’s efficacy will be assessed by evaluating heart structure and function, as well as blood biomarkers. Participants will be followed up for four years after completing the main part of the study to assess long-term safety and efficacy, resulting in a total of five years of monitoring.
According to Lexeo, preclinical studies showed that the gene therapy reversed cardiac abnormalities in models of FA, improved cardiac function and survival, and had a favorable safety profile.
LX2006 has previously been granted rare pediatric disease and orphan drug designations by the FDA, which are intended to accelerate the development of new treatments for rare diseases. In the U.S., a rare disease is one affecting less than 200,000 people.
“We believe today’s fast track designation, along with the previously announced rare pediatric disease and orphan drug designations granted to LX2006, will allow for enhanced regulatory interactions and the potential for this life-improving therapy to reach FA patients more quickly,” Townsend said.
