Friedreich Ataxia Has One Approved Drug. It Costs $370,000 a Year and Doesn't Touch the Heart Failure That Kills Most Patients.

Fifteen of 17. In a fatal disease with exactly one FDA-approved drug that costs $370,000 per year and does not address the organ that actually kills you, a research team just showed that a single intravenous injection reduced heart damage markers in 88% of patients. Published June 17 in JAMA Cardiology, the Phase 1 trial of AAVrh.10hFXN gene therapy represents both the first evidence that frataxin protein can be restored in human hearts and a stark economic indictment of how we currently treat Friedreich ataxia.

Friedreich ataxia (FA) affects roughly 1 in 50,000 Americans, about 5,000 diagnosed patients. A mutation in the FXN gene starves mitochondria of frataxin, a protein essential for iron-sulfur cluster assembly, and without it, cells that burn the most energy fail first. Neurons degrade and patients lose coordination, then the ability to walk. But the heart fails too: cardiomyopathy develops in the majority of patients and is responsible for up to 65% of deaths.

What Skyclarys Does, and What It Doesn't

Skyclarys (omaveloxolone), approved by the FDA in February 2023, activates the Nrf2 pathway to reduce oxidative stress. In its pivotal MOXIe trial, it improved neurological scores by 2.66 points on the 99-point mFARS scale over 48 weeks, a 2.7% improvement on a neurological rating scale at a cost of $370,000 per year with no demonstrated effect on cardiac outcomes.

Consider what that costs over a lifetime. FA typically manifests between ages 10 and 15. Modern life expectancy with cardiac involvement ranges from the mid-30s to 50, depending on disease severity. A conservatively estimated 25 years on Skyclarys costs $9.25 million per patient. For 5,000 US patients, that is $46.3 billion in cumulative pharmaceutical spending on a drug that does not treat the thing most likely to kill them.

One Injection, 17 Patients, Two Trials

Against that backdrop, researchers at Weill Cornell Medicine and Lexeo Therapeutics pooled data from two independent Phase 1 studies (NCT05302271 and NCT05445323). Between February 2022 and September 2025, 17 adults with FA cardiomyopathy received a single intravenous infusion of AAVrh.10hFXN at three escalating doses: 1.8×10¹¹, 5.6×10¹¹, and 1.2×10¹² viral genomes per kilogram.

What happened next is best read as a table.

Outcome	Result	Number Needed to Treat
Cardiac frataxin protein increase (biopsy at 3 months)	8/8 evaluated (100%)	1.0
High-sensitivity troponin I decrease ≥10%	15/17 (88%)	1.1
Left ventricular mass index decrease ≥10%	9/17 (53%)	1.9
Mean LVMI reduction at 12 months (elevated baseline, n=4)	11.4%	N/A
Serious adverse events	4/17 (3 prednisone-related, 1 myocarditis)	N/A

A Number Needed to Treat of 1.1 for troponin reduction means you treat roughly 10 patients and 9 respond. For a Phase 1 safety trial, those numbers are extraordinary. FA is a progressive disease. Cardiac biomarkers worsen over time without intervention. So the real comparison baseline is not "no change" but active, measurable deterioration.

Breaking Even: Gene Therapy vs. Skyclarys

No one has published pricing for AAVrh.10hFXN yet. But approved AAV gene therapies offer a bracket: Luxturna (retinal dystrophy) costs $850,000; Zolgensma (spinal muscular atrophy) costs $2.1 million; Hemgenix (hemophilia B) costs $3.5 million. All one-time infusions. All treating diseases with patient populations comparable to or smaller than FA's.

If AAVrh.10hFXN is priced at $2 million, it breaks even against Skyclarys in 5.4 years. At $3.5 million, break-even extends to 9.5 years. Neither estimate includes the cardiac hospitalizations, echocardiograms, MRIs, and cardiology visits that Skyclarys does nothing to prevent. A PROFA study published in The Lancet Neurology found annual societal costs of €32,679 ($35,293 at current exchange) per FA patient excluding Skyclarys. Add those in, and a $2 million gene therapy breaks even in 4.9 years.

Scenario	Lifetime Cost (25 years)	Cardiac Benefit
Skyclarys alone	$9.25M	None demonstrated
Skyclarys + societal care costs	$10.13M	None demonstrated
One-shot gene therapy at $2M	$2M + residual care	88% troponin reduction, 53% LVMI reduction
Gene therapy at $3.5M	$3.5M + residual care	Same

Wall Street's Vote of No Confidence

Lexeo Therapeutics (NASDAQ: LXEO) holds the commercial rights to AAVrh.10hFXN, having gone public in November 2023 at $11 per share. As of June 28, 2026, the stock trades at $4.75, a 57% decline that values the company at $373 million.

Divide that by the addressable US patient population, roughly 3,250 FA patients with cardiomyopathy (65% of 5,000 diagnosed), and investors are valuing Lexeo at $114,769 per potential patient. If the therapy were priced at $2.5 million per infusion, the total addressable market would be $8.1 billion, which means a $373 million market cap implies Wall Street assigns roughly a 4.6% probability-weighted chance that Lexeo captures its full market. Rare disease biotech gets punished by the same capital markets that reward $370,000-per-year maintenance drugs.

Conflict of Interest, Disclosed but Significant

Dr. Ronald G. Crystal, the study's lead author, is the founder, chairman, and largest individual shareholder of Lexeo Therapeutics. He holds the patent on the AAVrh.10 vector platform. He is simultaneously the principal investigator of one of the two trials whose data were pooled and the person who stands to profit most from their success. JAMA Cardiology requires conflict disclosure, and the paper includes one. But "disclosed" and "resolved" are different words. Readers evaluating these results should weigh the fact that the person designing the trial, analyzing the data, and writing the paper is also the person whose company's stock price depends on the outcome.

What This Analysis Does Not Show

Several limitations deserve explicit acknowledgment. First, 17 patients is a tiny sample in an open-label, non-randomized design without a control arm. Troponin I can fluctuate for reasons unrelated to the intervention. Second, the NNT calculations above assume a natural-history comparison of zero improvement, which is reasonable for a progressive disease but not the same as a placebo-controlled estimate. Third, the pricing comparisons use Zolgensma and Hemgenix as benchmarks, but AAVrh.10hFXN has no announced price. Lexeo could price it at $5 million or $500,000. Fourth, cardiac frataxin restoration was measured by endomyocardial biopsy in only 8 of 17 patients. Whether protein expression is durable beyond 3 months remains unknown. Finally, this trial enrolled patients with early cardiomyopathy (ejection fraction >45%). Whether gene therapy works in advanced cardiac disease, where it would matter most, is untested.

Strongest Counterargument

Skyclarys and gene therapy are not substitutes. Skyclarys targets Nrf2-mediated oxidative stress across the nervous system. Gene therapy restores frataxin in cardiac tissue. A patient with FA has both neurological and cardiac disease, and there is no reason to assume treating one eliminates the need for the other. Comparing their costs as though they compete for the same therapeutic slot overstates the case for gene therapy's economic advantage. If gene therapy succeeds, patients may still need Skyclarys for neurological progression, making total treatment costs additive rather than substitutive. Furthermore, Skyclarys is approved and commercially available today. Gene therapy is in Phase 1. Approval, if it comes, is likely five to seven years away. Pricing gene therapy against a drug that exists now is a comparison between the real and the hypothetical.

What You Can Do

If you or a family member has FA: ClinicalTrials.gov lists NCT05302271 (Weill Cornell) and NCT05445323 (Lexeo) as active. Contact the Friedreich's Ataxia Research Alliance (curefa.org) for enrollment guidance. Both trials are recruiting adults 18-50 with confirmed FA cardiomyopathy and ejection fraction above 45%.

If you are a clinician treating FA patients: Endomyocardial biopsy confirmed frataxin protein restoration in all evaluated patients. Monitor the dose-response data closely. The 1.2×10¹² vg/kg cohort showed the most consistent LVMI reductions, but also produced the one case of myocarditis at 12 months.

If you follow rare disease economics: Track the Komodo Research Data analysis (PMID 40614535), which found FA patients have 59.2 times higher odds of cardiomyopathy and 3.9 times higher mortality risk than matched controls. That ratio establishes the economic ceiling for what payers should be willing to spend on a cardiac-targeted therapy.

The Bottom Line

We have spent three years and billions of dollars prescribing a $370,000-per-year drug that does not treat the organ failure responsible for most Friedreich ataxia deaths. A 17-patient trial just demonstrated that a single injection can restore the missing protein in human hearts, and while it is too early to know if that translates into longer lives, the economics of the current treatment paradigm are already clear: $9.25 million per patient over a lifetime, with no effect on the primary cause of death.