Stifel analysts said that Lexeo’s data showing reduced size and thickness of the heart’s left ventricle are “supportive of a drug effect” for the company’s gene therapy in Friedreich’s ataxia cardiomyopathy.
Lexeo Therapeutics’ investigational gene therapy LX2006 can reduce the size and thickness of the left ventricle by one-fourth in patients with Friedreich’s ataxia cardiomyopathy, the biotech said in a data rollout on Monday.
In a note to investors, Stifel analysts called Lexeo’s findings “compelling and supportive of a drug effect” in this indication, adding that LX2006’s benefits manifest “early.” Additionally, the analysts noted that even patients with less severe heart disease symptoms “demonstrated disease stabilization.”
“It continues to look like there’s a real drug effect here given the consistency of effect across dose-cohorts and clinical measures,” Stifel wrote.
In its Monday readout, Lexeo focused on six patients with abnormal left ventricular mass index (LVMI) at baseline. Increased mass in the heart’s left ventricle is an indicator of a variety of heart diseases. In these patients, treatment with LX2006 resulted in a 25% mean improvement in LVMI at 12 months or sooner. Five of the six reached normal LVMI measurements by their latest visit.
The data also indicated a dose-dependent effect of LX2006, according Lexeo, adding that the gene therapy also aced key secondary cardiac, functional and patient-reported outcomes. In 12 patients who had been followed for at least six months, 10 saw reductions in lateral wall thickness while 11 demonstrated a more than 25% drop in high-sensitivity troponin I levels.
Cardiac frataxin, a protein that is under-expressed in Friedreich’s ataxia, increased in a dose-dependent manner at three months after LX2006 treatment, as per Lexeo’s release. According to Stifel, the gene therapy’s impact on frataxin is “encouraging” and its effects on other relevant biomarkers “corroborate the efficacy signal.”
With Monday’s findings, Lexeo is now planning to take LX2006 into pivotal trials, with a registrational study set to start by early 2026, building toward an efficacy readout in 2027.
“We view the co-primary endpoints as favorable, and believe [Lexeo] has a solid chance at success,” Stifel wrote.
Still, the analysts noted that there remains “uncertainty” for Lexeo—and for gene therapy developers more broadly—given the “recent changes” at the FDA, “but we think rare disease dynamics are probably less likely to change.”
Late last month, Peter Marks, former head of the FDA’s Center for Biologics Evaluation and Research (CBER), exited the agency over differences with the Trump administration’s health leadership, particularly regarding vaccines. As CBER head, Marks championed accelerated approvals for gene therapies for rare diseases and it remains to be seen whether his departure will change this regulatory flexibility at the agency.
