UPDATE 1-Solid Biosciences medicines chief to step down, to cut workforce by one third

(Adds details on executive departures, background)

Jan 9 (Reuters) - Solid Biosciences Inc said on Thursday its head of medicines would step down and that it would layoff one third of its workforce as the drug developer works to bring an end to the clinical halt on a trial of its experimental gene therapy.

The company intends to curtail development of all its other clinical programs and focus on its gene therapy for Duchenne muscular dystrophy, a muscle wasting disorder.

The trial was halted in November for a second time in less than two years after a seven-year-old-boy experienced serious complications.

Chief Medical Officer Jorge Quiroz will exit along with Chief Operating Officer Alvaro Amorrortu, the company said.

Solid had 111 full-time employees as of Dec. 31, 2018. (Reporting by Manas Mishra in Bengaluru; Editing by Shinjini Ganguli)