RA Capital and a fleet of other investors are putting $175 million behind Oak Hill Bio, a startup trying to revive an experimental Angelman syndrome drug that Roche shelved.

Oak Hill is competing with Ultragenyx Pharmaceutical and Ionis Pharmaceuticals, both of which are already running Phase 3 trials of similar drugs for the same disease. Ultragenyx will have results this year.

Oak Hill is betting it has the best molecule.