European Agency OKs Marketing Authorization for Puldysa to Treat Respiratory Decline in Duchenne MD

The European Medicines Agency (EMA) has validated a marketing authorization application for Puldysa (idebenone) for treating respiratory dysfunction in Duchenne muscular dystrophy (DMD) patients who do not take glucocorticoids.

This means that the submission, which was made as a conditional marketing authorization (potentially granted to therapies whose immediate benefit outweighs the risk of continuing clinical trials) is complete and that the review by EMA’s Committee for Medicinal Products for Human Use (CHMP) has started. Santhera Pharmaceuticals, the company marketing Puldysa, expects a decision in mid-2020.

“The initiation of the CHMP review of our application is an important milestone for patients with DMD who currently have no alternative treatment for the preservation of respiratory function,” Kristina Sjöblom Nygren, MD, Santhera’s chief medical officer and head of development, said in a press release.

“We are looking forward to working closely with the rapporteurs and CHMP during the review process to make Puldysa available to patients as soon as possible,” Nygren said.

If granted EMA approval, Puldysa will earn marketing authorization in all member states of the E.U., as well as in Norway, Liechtenstein, and Iceland. The EMA already has granted orphan drug designation to the therapy for DMD.

Glucocorticoids are the only available option to slow the decline in muscle strength and function in DMD patients. However, their effectiveness is limited and adverse side effects may occur.

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Puldysa is a synthetic benzoquinone, a compound with antioxidant and anti-inflammatory properties. It is able to help muscle cells maintain their cellular energy supply, compromised in DMD patients by the characteristic lack of the protein dystrophin.

The application was based on Phase 2 and 3 clinical trials. DELOS , a Phase 3 study (NCT01027884), lasted 52 weeks and included 64 participants aged 10–18 years, who received either Puldysa at 900 mg/day or a placebo and were not taking steroids.

The results showed that Puldysa eased the loss of respiratory function —  assessed via changes in percent predicted peak expiratory flow and forced vital capacity (the amount of air exhaled after a deep breath) — delaying the need for assisted ventilation by three years. However, despite the positive results collected during DELOS, the EMA issued two negative recommendations against extending the therapy’s label beyond the treatment of patients with Leber’s hereditary optic neuropathy, under the trade name Raxone.

Data supporting the use of Puldysa in boys with DMD also had been seen in the DELPHI Phase 2 study (NCT00654784) and its two-year extension study, called DELPHI-E (NCT00758225).

In turn, the SYROS study collected long-term respiratory function data from 18 patients who completed DELOS and subsequently took Puldysa under expanded access programs. The findings again demonstrated sustained reductions in the rate of respiratory dysfunction for up to six years.

The Switzerland-based company is currently enrolling participants for the international Phase 3 SIDEROS trial (NCT02814019), which is testing the ability of Puldysa to prevent respiratory decline in patients on glucocorticoids. A total of 266 patients are expected to participate across 60 locations in the U.S., Europe, and Israel.

Participants who complete SIDEROS may join its open-label extension (NCT03603288), which aims to evaluate Puldysa’s long-term safety and effectiveness.