- Commercial stage biopharma Sarepta Therapeutics has signed an exclusive partnership with Myonexus Therapeutics covering five limb-girdle muscular dystrophy (LGMD) gene therapies, two of which are in preclinical testing and three are in clinical trials.
- Sarepta will pay $60 million upfront, followed by milestone payments of up to $45 million. Under the terms of the deal, Sarepta has an exclusive option to purchase Myonexus at any time for a pre-negotiated, fixed price with sales-related payments.
- The collaboration aims to develop corrective treatments for five distinct forms of LGMD. Sarepta plans to give an update on its entire pipeline and data in June 2019.
Limb-girdle muscular dystrophy is a group of rare muscle disorders that affect the muscles around the hips and shoulders. These are degenerative and potentially life-threatening diseases, each with different symptoms and outcomes, including fatal cardiopulmonary complications.
Myonexus' focus is on the five most common and severe forms, and its lead candidate targets LGMD2E, also known as beta-sarcoglycanopathy. The experimental drug uses the same vector system as Sarepta's micro-dystrophin gene therapy program. In preclinical models, MYO-101 restored a full length version of the affected protein, beta-sarcoglycan, and returned function in mice.
"We will commence the first [Phase 1/2a] clinical trial with MYO-101, begin development for Limb-girdle 2e in mid-2018, and we will report gene expression data in late-2018 to early-2019," said Sarepta CEO Doug Ingram on the company's first quarter earnings call.
Other products covered by the ingredient are: MYO-102 for LGMD2D; MYO-103 for LGMD2C; MYO-201 for LGMD2B; and MYO-301 for LGMD2L.
Sarepta has a marketed product for Duchenne muscular dystrophy, Exondys 51 (eteplirsen). In a process that was more dramatic than usual, the Food and Drug Administration approved the exon-skipping drug for DMD in September 2016. Things weren't straightforward after approval either; insurer Anthem initially stated that it would not cover the drug, and then reversed its decision just over a year later. Exondys 51 sales were $65 million in the first quarter of 2018, and are forecast to total between $295 million and $305 million for the full year.
Golodirsen, which targets patients skipping exon 53 of the DMD gene, is on track to complete a rolling New Drug Application submission by the end of 2018, with potential approval in mid-2019.
"From a commercial perspective, the partnership with Myonexus Therapeutics makes strategic sense because with success we would be calling upon the same neuromuscular experts with whom we have relationships," said Bo Cumbo, Sarepta chief commercial officer, on the call. "Between our gene therapy programs for both DMD and limb-girdle muscular dystrophy, our team is preparing to launch up to six different gene therapy programs within the two year window of time."