Edward M. Kaye, M.D., will resign as president and CEO of Sarepta Therapeutics, the company has disclosed in a regulatory filing, after a year and a half, during which he steered the company to gaining a controversial first-ever approval by the FDA for a Duchenne muscular dystrophy (DMD) treatment.

Dr. Kaye will remain a director on Sarepta’s board and serve the company as a special regulatory and scientific advisor following his resignation from the company’s helm, which was unexpected. Dr. Kaye will resign “upon the conclusion of his current employment term on September 20, 2017 or some other future date,” according to the filing, submitted yesterday to the U.S. Securities and Exchange Commission.

The filing did not say who would succeed Dr. Kaye as CEO.

During a conference call with analysts yesterday, Dr. Kaye said he resigned in order to focus on upcoming initiatives for Sarepta—including approval of Exondys 51™ (eteplirsen) in Europe, advancement of treatments based on the company’s phosphorodiamidate morpholino oligomer (PPMO) platform, and advancement of additional DMD treatments, including gene therapy.

“With the approval of Exondys 51 and our successful transition to a commercial-stage entity, as well as the initial steps we've taken toward becoming a global company, I believe now is the right time to narrow my focus on the key areas of the business where I can have the most impact,” Dr. Kaye said, according to published transcripts of the conference call.

Until this month, Dr. Kaye had also been Sarepta’s chief medical officer—a position he relinquished when Catherine Stehman-Breen, M.D., joined the company as svp and CMO.

Dr. Kaye became CEO in 2015 following the resignation of predecessor Chris Garabedian, and led Sarepta in successfully persuading the FDA to approve Exondys 51, indicated for DMD amenable to exon 51 skipping.

Exondys 51 generated $16.3 million in net product revenue during the first quarter, in what the company said was a successful launch of the treatment. Sarepta yesterday raised its net revenue guidance for this year from more than $80 million to more than $95 million.

The FDA approved Exondys 51 on September 19, 2016, despite recommendations by two advisory committees against approving the treatment and over objections from some administrators. Those administrators included the then-director of the FDA’s Office of New Drugs (OND), John K. Jenkins, M.D., subsequently retired from the federal government.

Dr. Jenkins and other opponents of Exondys approval were overruled by administrators who included Janet Woodcock, M.D., director of FDA’s Center for Drug Evaluation and Research (CDER), and the FDA’s then-Commissioner Robert M. Califf, M.D. Parents of boys with DMD argued that neither FDA nor clinical studies had found any safety problems with eteplirsen, and that the drug improved patients’ conditions—though Dr. Califf later called for retraction of a 2013 clinical study that help support the approval.

Upon winning approval for Exondys 51, Sarepta also obtained a Rare Pediatric Disease Priority Review Voucher (PRV) that it sold to Gilead Sciences in February for $125 million upfront.