As far as troubled backstories go, Sarepta Therapeutics’ Exondys 51 has a doozy with a contentious approval process and a major insurer backing away from the targeted therapy. Now the pricey Duchenne muscle dystrophy (DMD) treatment has a new problem: an influential gatekeeper says it simply isn’t cost-effective.
At its current list price of $892,000 per year, Exondys 51 “would not be cost-effective … even with assuming extremely favorable treatment effects that are not credible given clinical experience,” according to a Thursday draft evidence report from the Institute for Clinical and Economic Review (ICER).
The ICER report also looked at Sarepta’s DMD follow-up hopeful golodirsen and PTC Therapeutics’ Emflaza—which isn't cost-effective, either, at least not at its current list price of $62,900, the organization said.
DMD is an ultra-rare and often fatal neuromuscular condition that results in the progressive loss of muscle function. An estimated 400 to 600 patients are diagnosed in the U.S. each year. Exondys is the only therapy approved to treat a small subset of the DMD patient population with a particular genetic mutation.
In its report, ICER measured the three treatments against corticosteroid supportive care, the current standard in DMD, and in Exondys’ case found little clinical evidence the drug was cost-effective at any price, let alone its current list.
“The underlying evidence for evaluating the cost-effectiveness of treatments in DMD remains sparse,” ICER wrote. “For (Exondys), at its current price, no plausible treatment effects were found to make this treatment reach cost-effectiveness thresholds. Similar results are expected of golodirsen if it is priced similar to (Exondys).”
Those findings are even more troubling news for Exondys, which has had a troubled path to launch, to say the least.
In 2016, Exondys received FDA approval after officials expressed sincere doubts about the therapy’s clinical effectiveness, based on an unusually small patient pool and wishy-washy results in improving motor function. External pressure also had a part to play in the decision after hundreds of advocates stormed an FDA advisory committee meeting to demand the drug’s approval despite its trial shortcomings.
Despite bowing to the full-court press, the FDA required Sarepta to launch a follow-up trial aimed at beefing up its limited clinical findings. The results of that study are due in May 2021.
But after that long-awaited success, Sarepta was stung by major U.S. insurer Anthem’s decision not to back Exondys, citing “uncertainty” in whether the drug actually worked. And in 2018, pharmacy benefits manager Express Scripts dropped the treatment from its preferred formulary list, again referring to unclear clinical data.
With Exondys’ future in the air, Sarepta has leaned heavily into follow-up candidates and other indications, with FDA approvals in limb girdle muscular dystrophy and four other hopefuls in the pipeline. RBC Capital Markets analyst Brian Abrahams said Sarepta could be looking at more than $3 billion in additional revenue tied to four meds it's developing in mucopolysaccharidosis type IIIA, Charcot-Marie-Tooth type 1A, Pompe disease and LGMD 2A.
“While many are still early and have risk, and not all share exactly the same attributes as the DMD/LGMD programs, based on our analysis of their respective profiles, we are increasingly confident that (Sarepta) will be able to leverage its growing gene therapy expertise to drive success,” Abrahams said.