Ultragenyx Resumes Dosing Antisense Trial In Rare Neurogenetic Disorder - Ultragenyx Pharmaceutical (NASDAQ:RARE)

The FDA has removed the clinical hold on GeneTx Biotherapeutics LLC and Ultragenyx Pharmaceutical Inc's RARE GTX-102 trial for Angelman syndrome.
The companies can begin dosing naïve patients in the Phase 1/2 study of GTX-102 in pediatric patients.
Ultragenyx paused dosing after patients temporarily lost the ability to walk. All subjects had lower extremity weakness after receiving GTX-102.
Under the amended U.S. protocol, eight patients (4 to less than 8 years of age) who were not previously treated with GTX-102 will be enrolled into two groups, an active group, and an age-matched comparator group.
The active group will receive four monthly 2 mg of GTX-102, while the comparator group will have limited assessments at baseline and Day 128.
Patients in the comparator group will then be eligible to receive GTX-102 under the same dosing strategy as the active group.
All U.S. patients who have completed the dose-loading phase will then move to a maintenance phase during which they will receive 2 mg of GTX-102 every three months and continue to be monitored for response and safety.
GeneTx previously received clearance, under a separate amendment, to begin the Phase 1/2 study in the U.K. and Canada.
Under the protocol approved in the U.K. and Canada, approximately 12 patients will be enrolled into two cohorts split by age.
The starting doses in Cohorts 4 and 5 will be 3.3 and 5 mg, respectively. Patients will receive three to four monthly doses and will then move to a maintenance phase.
Related content: Benzinga's Full FDA Calendar.
Price Action: RARE stock is down 2.29% at $92.93 during the market session on the last check Monday.

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