Santhera Seeks European Approval of Puldysa to Address Respiratory Problems in DMD

Santhera Pharmaceuticals has submitted a marketing authorization request to the European Medicines Agency (EMA) for Puldysa (idebenone) as a treatment for respiratory dysfunction in patients with Duchenne muscular dystrophy (DMD).

The request is made as a conditional marketing authorization (CMA), which may be granted to medicines whose benefit of immediate availability outweighs the risk of continuing clinical trials to gather data about the therapy. Valid for one year, the CMA can be renewed annually, and the applicant is expected to outline a timeline for delivering additional data.

Under the CMA, Puldysa will be used to treat respiratory dysfunction in patients with DMD who are not using glucocorticoids. Glucocorticoids are the only available treatment for slowing the decline in muscle strength and function in DMD. The therapy is not targeted to specific disease-causing mutations. The effectiveness of glucocorticoids, however, is limited and linked to side effects.

Santhera’s request to EMA is supported by data from Phase 2 and Phase 3 clinical trials, namely DELOS (NCT01027884) and the recently completed SYROS trial.

The Phase 3 DELOS study enrolled 64 patients, age 10 to 18, who were randomized to receive either idebenone (900 mg/day) or a placebo three times a day with meals for 52 weeks. Results showed that idebenone reduced the loss of respiratory function, delaying the need for assisted ventilation by three years.

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In the SYROS trial, researchers collected long-term, retrospective real-world data from 18 patients who completed the DELOS study and continued idebenone treatment (same dose) for about 4.2 years (ranging from 2.4 to 6.1 years).

The trial measured patients’ respiratory function for up to six years and compared it with the period before idebenone treatment.

Once again, the results showed that idebenone reduced respiratory function decline by 50%, measured by the predicted forced vital capacity of each patient.

“The new data included in this regulatory submission confirm clinically relevant patient benefits and long-term therapeutic efficacy with idebenone in patients with DMD. Thereby, we have closed earlier data gaps and respond[ed[ to requirements from the regulatory authorities,” Kristina Sjöblom Nygren, MD, chief medical officer and head of development at Santhera said in a press release.

Santhera is currently recruiting participants for the Phase 3 SIDEROS study (NCT02814019), which is evaluating whether Puldysa is able to prevent respiratory decline in DMD patients taking glucocorticoid steroids over a period of 18 months. The trial is enrolling an estimated 266 patients, making it the larger actively recruiting DMD trial, across 60 clinical sites in the U.S., Europe and Israel. To date, 214 patients have enrolled.

Participants who complete the SIDEROS trial may enroll in the open-label SIDEROS-Extension study (NCT03603288) that aims to assess the long-term safety and effectiveness of Puldysa in DMD patients.

Idebenone is a synthetic analog of ubiquinone, a key antioxidant that also plays a role in the cellular production of energy. The chemical compound allows muscle cells to maintain their cellular energy supply, which has been compromised by a disease-specific lack of dystrophin.

Idebenone, marketed under the brand name Raxone, is already approved in Europe to treat visual impairment in adults and adolescents 12 and older who have Leber hereditary optic neuropathy (LHON). For treatment in DMD patients, it will be marked as Puldysa to differentiate between the two indications.