- Regeneron said Friday that multiple patients died during the extension portion of a clinical trial evaluating one of its drugs in an ultra-rare disease. The biotech is investigating whether its drug is the cause, but in the meantime has told trial researchers to stop dosing patients.
- Early this year, Regeneron claimed victory in the main portion of the trial — which found that half a year into treatment, patients with a condition known as FOP showed significantly greater decreases in lesions than patients who got a placebo. FOP, or fibrodysplasia ossificans progressiva, is a disease in which bone grows in muscle tissue, leading to skeletal deformities, mobility loss and an early death. There are currently no approved therapies for the disorder.
- To Baird analyst Brian Skorney, Friday's news completely changed the outlook for Regeneron's drug, called garetosomab. While the prior results could have supported an approval, the new safety signals make that outcome unlikely, Skorney wrote. As a result, the Baird team has removed garetosomab from its models for Regeneron.
In January, with positive results from their LUMINA-1 trial in hand, Regeneron leadership said they intended to work with the Food and Drug Administration and other regulatory agencies to make garetosomab available to patients.
The main part of the study had found lesion activity declined 25% in drug-treated patients compared to placebo-treated patients — with a particularly noticeable effect on new lesions, which decreased 90% in comparison to the placebo group.
Regeneron also said patient-reported flare-ups fell by 50% over the course of the trial. Investigators reported adverse flare-up events in 10% of the garetosmab arm and 42% of the placebo arm.
That positive data is now overshadowed by the deaths, however. Regeneron didn't disclose how many patients have died during the extension period, and declined a BioPharma Dive request for further details. The three-part trial enrolled 44 patients, who either received garetosomab or placebo for six months before progressing to an open-label period in which placebo-treated patients switched onto garetosmab. After that, patients receive open-label follow-up treatment.
While Regeneron tries to determine whether garetosomab played a role in the patient deaths, the optimism around the drug may dim.
"[W]e no longer expect this medication is likely to gain approval given the occurrence of these serious safety events in the open-label portion of the study," Skorney wrote in a Nov. 1 note to clients.
Baird's price target for Regeneron shares is now down to $570 from $600, also in part because of a Friday update on the company's COVID-19 drug.
Regeneron isn't the only company to find unexpected challenges in FOP drug development. Last December, the FDA partially halted testing for all patients under 14 participating in studies of palovarotene, a drug being advanced by the Paris-based pharmaceutical company Ipsen.
A month later, Ipsen said it had paused dosing in two studies of palovarotene, after independent reviewers concluded the larger of those trials was unlikely to succeed. The FDA cleared Ipsen in March to resume testing the drug in FOP patients who are 14 or older.