Ultragenyx buys gene therapy partner after new study results

Dive Brief:

• Ultragenyx Pharmaceuticals has acquired privately held GeneTx BioTherapeutics for $75 million, convinced an experimental therapy the two companies are developing has promise for treating a rare neurogenetic condition known as Angelman syndrome.
• Ultragenyx and GeneTx have been working together on the therapy since August 2019, when Ultragenyx secured an option to buy the smaller drug developer that it’s now followed through on. Along with the upfront payment, Ultragenyx has promised as much as $115 million more if certain milestones are met.
• The acquisition was announced by the companies Monday afternoon alongside interim results from a small clinical trial testing their treatment in the U.K., Canada and the U.S. The data, Ultragenyx said, supported changes in its testing plans that will allow higher doses to be studied across more patients in the U.K. and Canada.

Dive Insight:

The study results released by Ultragenyx Monday are preliminary and come from just 14 patients. But Ultragenyx saw enough to go forward with an acquisition that gives it full control of the therapy and its future development.

The disease it’s targeting, Angelman syndrome, has no current treatment and causes delays in development as well as problems with communication, balance and motor function. The condition is triggered by a missing or mutated version of a gene known as UBE3A, resulting in little expression of the related protein.

Ultragenyx’s treatment — a type of drug known as an antisense oligonucleotide — is designed to reactivate expression of another version of the gene that’s paternally inherited but is naturally silenced. However, testing was stopped in October 2020 after lower limb muscle weakness left two of five initially treated patients temporarily unable to walk. Regulators in the U.K., Canada and, eventually, the U.S. allowed the study to resume, but at lower treatment doses.

Across the 14 patients treated under the new dosing plan, there were no treatment-related serious adverse reactions, Ultagenyx said Monday, nor any side effects related to lower extremity weakness. Vomiting, COVID-19 and transient back pain were the most commonly reported adverse events in this group.

Efficacy results showed seven of nine patients in the U.K. and Canada with data through day 128 of the study experienced improvement from baseline in at least three of five areas, like sleep, behavior or communication. Most of the improvements were rated as “minimal” on the rating scale used, although other patients experienced more significant benefits.

Both patients who were evaluable in the U.S. group had similar-level improvements on at least three of five areas as well.

“The changes that we have seen clinically in less than a year in both the original five patients and the current patients … may seem small but are truly important improvements, given the rate of developmental progress in Angelman syndrome,” said Elizabeth Berry-Kravis, a professor of pediatrics at Rush University Medical Center and a study investigator, in a statement provided by Ultragenyx.

Others were more cautious. The therapy’s efficacy was not “as dramatic” as reported for the earlier cohort, analysts at Piper Sandler wrote in a note to clients, adding that “there nonetheless is a treatment effect.”

Joseph Schwartz, an analyst at SVB Securities, described the data in a note to clients as “encouraging but variable.”

With the data in hand, Ultragenyx now has regulators’ approval in the U.K. and Canada to enroll new patients with higher starting doses based on age. In the company’s statement, CEO Emil Kakkis said he expects the greater dose levels to be more efficacious. (The maximum dose under the new plan is still lower than what was originally tested in the first five patients.)

Ultragenyx plans to discuss its dosing plan with the Food and Drug Administration, which required lower dosing than in the U.K. and Canada. Further updates are expected in late 2022 or early 2023, the company said.

GeneTx was launched in 2017 by the Foundation for Angelman Syndrome Therapeutics, and licensed its technology from Texas A&M University.

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