Words by Jade Williams
The FDA has lifted its partial clinical hold on ersodetug, a novel therapy for the treatment of congenital hyperinsulinism (HI) after new research showed that the previous adverse results seen in laboratory rats may not have been caused by the drug itself.
This partial hold on the drug was originally imposed in 2022 due to historical preclinical data suggesting liver toxicity in Sprague-Dawley laboratory rats treated with ersodetug. This liver toxicity has now been shown to be rat species specific and does not pose a risk to human safety. However, the agency has imposed some restrictions, including dose restrictions for studies of ersodetug.
In May 2023, the rare disease company behind the drug Rezolute completed a follow-up toxicology study that showed no liver abnormalities, prompting regulatory authorities and clinical investigators to reconsider the clinical hold.
“We are delighted that FDA has completely removed the partial clinical holds and are allowing us to proceed in the US at all doses and in participants as young as three months of age as part of our ongoing global study,” said Nevan Elam, Founder and CEO, Rezolute. “Of note,” he continued, “FDA specifically concluded that the liver toxicity observed in Sprague Dawley rats is likely strain-specific and not otherwise relevant to humans.”
This update comes as Rezolute prepares for enrolment into sunRIZE, a global phase III study, in early 2025, with study results anticipated in the second half of the year. The trial will test whether ersodetug helps patients with congenital HI, a genetic disorder leading to dangerously low blood sugar levels. It is set to involve up to 56 participants between the ages of three months old to 45 years old across more than 12 countries.
