Armed with a patented version of a drug first approved in 1973 for a much different use, Soleno Therapeutics Inc. has initiated a phase III trial aimed at addressing one of the chief symptoms of Prader-Willi syndrome (PWS): insatiable hunger, or hyperphagia. The Redwood City, Calif.-based company, formed last year after Capnia Inc. acquired Essentialis Inc., has already scored both U.S. and EU orphan status for the drug, a controlled-release formulation of diazoxide choline. Now, with its trial kicking off at Seattle Children's Hospital, it's getting closer to potentially addressing a large portion of the 300,000 to 400,000 individuals worldwide with the rare genetic condition.