BIONEWS
Oak Hill Bio raised $175 million to compete with two rivals already in Phase 3 for Angelman syndrome, a rare brain disorder with no approved therapy.
A Roche-shelved molecule that sat in development limbo is now the basis for a $175 million bet that the third company to start a Phase 3 trial in Angelman syndrome can still finish first. Oak Hill Bio closed the financing from RA Capital and a syndicate of other investors this month, the company said, and is also merging with the SPAC Research Alliance Corporation III to become a publicly listed rare-disease biotech (BioSpace mirror of the announcement). The trigger, according to STAT News, was RA Capital leading a $175 million financing round for Oak Hill Bio to compete with Ultragenyx and Ionis in the same disease (STAT+).
Angelman syndrome is a rare genetic disorder, often diagnosed in infancy, that causes severe developmental delays, seizures, and a characteristic happy demeanor with frequent laughter. There is no approved disease-modifying treatment; current care focuses on managing symptoms. The disorder traces to a missing or silent copy of the UBE3A gene on the chromosome inherited from the mother. The brain can partly compensate using the father's copy, but only if a long non-coding RNA called UBE3A-ATS is suppressed. All three competing drugs are antisense oligonucleotides, or ASOs: short synthetic strands designed to bind that RNA and unsilence the paternal UBE3A copy.
Ultragenyx's GTX-102 sets the clock for the field. Phase 3, the large, late-stage clinical trial that usually precedes a regulatory filing, is the threshold each program is racing to clear. The company said in May it had finished enrolling the Phase 3 Aspire study, and a readout is expected this year (Ultragenyx IR). A positive result would give Ultragenyx a regulatory filing and, plausibly, a multi-year head start on the market. Ionis is also already dosing patients in its pivotal Phase 3 REVEAL study of ION582 (Ionis IR). Oak Hill is the third company to reach this stage; its BEACON Phase 3 study is registered on ClinicalTrials.gov as NCT07605429.
Oak Hill's argument for entering third is chemistry. Rugonersen, the company's drug, was originally developed at Roche, which stopped work on it before Oak Hill's founders revived the program. The Phase 1 TANGELO study was published in Nature Medicine, the company said, with a 50-milligram dose showing improvements across sleep, seizure, and communication endpoints (Oak Hill Bio announcement, Angelman Syndrome Foundation). Oak Hill's pitch is that the three ASOs differ enough in target site, chemistry, and delivery that the "best molecule" question is not yet answered.
The investment case rests on that bet, and the upcoming Phase 3 readouts will be the first hard test. GTX-102 has a documented history that includes an FDA partial clinical hold on the lower-back delivery procedure, a context the program's later data resolved. Rugonersen and ION582 were designed with different chemistry and delivery approaches. A cleaner safety profile, more durable effect, or easier dosing would each be enough to justify the bet. Ultragenyx's Aspire readout will be the first hard Phase 3 data point from any of the three programs, and Oak Hill's BEACON study is still enrolling.
Oak Hill is capitalized to make the bet publicly. The $175 million round follows an earlier $32.5 million Series A (Fundraiseinsider) and the SPAC merger, a deal that takes a private company public by combining it with a shell already listed on a stock exchange. A third-place entry chasing a defined clock is a familiar pattern in rare-disease drug development. The shelved-asset revival has produced real wins; it has also produced programs that returned to the shelf when a faster rival won the race. The next visible milestone is the Aspire readout window later this year.