Sarepta, BioMarin iron out Exondys 51 patent terms
- Sarepta Therapeutics and BioMarin Pharmaceutical plan to end a long-standing patent showdown through a new truce that would give one side a payout and the other rights to a class of drugs aimed at treating rare illnesses.
- The pending licensing agreement would have Sarepta fork over $35 million upfront for BioMarin's patent estate for Duchenne muscular dystrophy (DMD) treatments that work via exon-skipping. The big biotech can also reap milestone and royalty payments for compounds targeting exons 45, 53 or 51 — such as Sarepta's Exondys 51 (eteplirsen) — in the dystrophin gene, and possibly more products down the line.
- Importantly, should BioMarin want to develop its own exon-skipping therapy for DMD, the company can change the agreement to give itself co-exclusive rights to the estate. In order for the deal to close, it must be approved by Academisch Ziekenhuis Leiden (AZL), a research institute from which BioMarin licenses certain patent applications.
Patent disputes between the two drugmakers over exon-skipping DMD treatments have persisted over the last few years. As is often the case with pharma litigation, the battles appeared to be about shooing away competition. At the time, Sarepta was progressing with Exondys 51, while BioMarin was working on its own therapy, dubbed Kyndrisa (drisapersen).
The Food and Drug Administration rejected the latter drug in early 2016, though, resulting in the biotech shuttering drisapersen development. Conversely, the agency OK'd Exondys 51 before the end of September, bringing to U.S. market the first treatment for DMD.
For a second, right after Exondys 51's approval, Sarepta looked as though it would come out on top in the patent battle too. The U.S. Patent Trial and Appeal Board sided in favor of the company, refusing claims from AZL. However, BioMarin and AZL quickly appealed that decision.
Now, the patent storm is clearing up for both companies — taking some of the pressure off Sarepta, which already has plenty of other obstacles related to Exondys 51.
"If BioMarin or any of our competitors are successful in obtaining regulatory approval for any of their product candidates, it may limit our ability to gain or keep market share in the DMD space or other diseases targeted by our exon-skipping platform and product candidate pipeline," Sarepta said in its most recent 10-Q filing with the Securities and Exchange Commission.
Moving forward, Sarepta will likely focus on continuing to assuage payer distaste for the $300,000 per year price tag it set for Exondys 51. Last year, Anthem flat out said it wouldn't cover the treatment, whereas Humana decided to cover only patients who had received prior authorization.
Sarepta is also surely trying to avoid the same setbacks that Marathon experienced when it brought the second FDA-approved drug for DMD, Emflaza (deflazacort), to market. The treatment's lofty annual price of $89,000 spurred much backlash, and Marathon ended up offloading it to PTC, which immediately saw its stock fall from the transaction. Unlike Exondys 51, Emflaza is a corticosteroid that has been used off-label for the treatment of DMD for years.
According to an 8-K filed on July 18, Sarepta agreed to pay BioMarin milestone payments for Exondys 51, as well as casimersen and golodirsen, products that skip exons 45 and 53, respectively. As for royalties, Sarepta is to pay its partner 5% of net sales on exon-skipping products through 2023 in the U.S. and 8% of net sales on those medicines through Sept. 30, 2024 in the E.U. and other countries wherein the BioMarin and AZL patents still stand.
BioMarin may also receive another $10 million through a milestone payment that kicks in if Exondys 51 gains approval from the European Medicines Agency, and a $15 million payment should the drug ever hit $650 million in sales.
During the first quarter, Exondys 51 garnered $16 million in net revenue.
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