Confirmatory Studies May Expand Uptake of Exondys 51



Demand trends

Sarepta Therapeutics (SRPT) reported that by the end of 3Q17, all Tier 1 and Tier 2 sites, which will be treating around 75% of DMD (Duchenne muscular dystrophy) patients with mutations amenable to exon-51 skipping, had submitted start forms for Exondys 51 (eteplirsen). The company has also witnessed an increase in start forms submitted by Tier 3 sites. Also, by the end of 3Q17, around 160 independent physicians had submitted start forms for the drug.

Currently, the average age of patients on Exondys 51 therapy is 13 years. However, as increasing awareness and expanding coverage helps diagnose younger patients, Sarepta expects the average age of patient on therapy to decrease.

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Sarepta has also played a pivotal role in creating awareness among payers, who now have a better understanding of DMD as well as about patients who are covered by their plans and will be benefiting from Exondys 51 therapy. Other rare disease players, such as Alexion Pharmaceuticals (ALXN), United Therapeutics (UTHR), and Alnylam Pharmaceuticals (ALNY), also focus on awareness initiatives as part of their business strategy. Sarepta Therapeutics accounts for around 0.11% of the iShares Russell 2000 ETF’s (IWM) portfolio.

Confirmatory studies

Since Exondys 51 was approved under the FDA’s accelerated approval process, Sarepta has been involved in designing confirmatory trials for early- and late-stage patients. Data from these trials as well as real-world evidence seen by around 100 key opinion leaders and physicians are expected to help further convince payers of the utility of Exondys 51.

Payers have also been reaching out to physicians to discuss the utility and safety of Exondys 51. This systematic feedback approach is expected to increase reauthorization rates for patients already on Exondys 51 therapy. In the next article, we’ll discuss Golodirsen’s research program in greater detail.


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