Ultragenyx exercises option to acquire GeneTx

Along with providing a program update on GTX-102 for the treatment of Angelman syndrome (AS), Ultragenyx Pharmaceuticals (Nasdaq: RARE) today announced it will acquire GeneTx Biotherapies, its partner on the candidate.

However, investors were not impressed, sending Ultragenyx’ shares down almost 22% to $49.93 following the announcement.

The company revealed what it described as encouraging interim data from the open-label, dose-escalating Phase I/II study in pediatric patients who have a genetically confirmed diagnosis of full maternal UBE3A gene deletion. Interim results on nine patients from the UK/Canada arm and two patients from the US arm of the Phase I/II study demonstrate a meaningful improvement in clinical disease and an acceptable safety profile. These interim data supported a protocol amendment to the Phase I/II study that was approved by the UK and Canadian health authorities in May 2022 to initiate additional, new cohorts of patients at higher monthly loading doses. The study has begun to enroll under the amended protocol and has dosed the first patient in these new cohorts.