A Durham-based pharmaceutical company saw its stock drop by more than 12 percent Monday after it announced positive results from a study done on a drug treating ototoxicity.

Fennec Pharmaceuticals Inc. opened Monday at $12.04 but dropped as low as $9.99 — its lowest mark since moving its stock to the NASDAQ in September — before closing at $10.59.

On Friday, Fennec concluded the third phase of a study of PEDMARK, the company’s drug for pediatric cancer patients. It found the drug reduced platinum chemotherapeutic ototoxicity, or platinum chemotherapy-induced hearing loss, of pediatric cancer patients, according to a filing with the Securities and Exchange Commission.

“We are very pleased with the results of this study,” CEO Rosty Raykov said in a statement. “We would like to thank all the patients and their families who participated in this trial, physicians, the entire SIOPEL 6 team, and Dr. Neuwelt and his research team at OHSU. We believe that if approved PEDMARK would be an important therapy for patients and caregivers where currently there are no treatment options.”

The study found that 67 percent of evaluated patients who did not receive the drug during platinum chemotherapy experienced hearing loss while just 37 percent of evaluated patients who did receive the drug during platinum chemotherapy experienced hearing loss.

“I am absolutely delighted that after 30 years of research we have found a safe way to reduce ototoxicity in children receiving platinum containing chemotherapy,” said Penelope Brock, M.D., PhD, International Chair of SIOPEL. “This means that children who are cured from cancer after receiving platinum treatment can look forward to a normal healthy life, fully integrated into society. I believe this marks a new standard of care in pediatric oncology.”

Fennec presented the results at the 49th Congress of the International Society of Pediatric Oncology 2017 Meeting. It will pursue approval of PEDMARK from the Food and Drug Administration as well as the European Medicines Agency, according to the Form-8K.

The filing can be found here.