The Cost of Getting RNA to Mumble

By Mark McQuain

In my previous blog entry, I crudely summarized the genetic basis for Duchenne Muscular Dystrophy (DMD) and one pharmaceutical company’s (Sarepta) current effort to research, manufacture and finance a genetic treatment that increases the production of a muscle protein missing in patients with DMD called dystrophin. Please see my previous blog entry for that summary or this article for a more detailed thorough overview of the science and investigational process to date. For this blog entry, I want to consider the bioethics of the cost of Sarepta’s treatment eteplirsen (Exondys 51), currently estimated on average to be around $300,000 per year.

DMD is a devastating disease that generally causes the patient’s death by his mid-twenties but it only affects a very small number of boys and young men worldwide, estimated to be around 400-600 newborn males in the US each year. This small number of patients places medications for DMD in a category called Orphan Drugs, those that benefit fewer than 200,00 people per year. Eteplirsen is only beneficial in the 15% of DMD patients that have the specific RNA defect in dystophin protein production that eteplirsen corrects. Back-of-the napkin calculations mean that if 15% of all 600 boys born in the US every year with DMD (90 boys per year) used Sarepta’s $300,000-per-year drug, that is a $27 million increase in revenue (not profit) to Sarepta each year. While that sounds huge, it ignores the massive expensive cost barriers to bringing such a drug to market, including research, investigational studies to gain FDA approval and legal financial risk with future adverse effects yet unknown. Inability to gain FDA approval prohibits access to capital markets necessary to fund such a process. Were it not for grants available for orphan drugs, it is unlikely that eteplirsen would exist. Better for drug makers to target their R&D to a bigger disease market for the chance of a bigger reward (consider Bayer aspirin and their $3.3 BILLION profit in 2011 alone).

There are calls for Sarepta to “give back” some of their potential future income, calls from the very organizations that were their staunchest supporters in their FDA approval process. Strong ethical arguments are made that the company did benefit early on by using federal grants and this alone should require the company to reduce a portion of their future income by lowing the cost to patients. Calls for the FDA to federalize Sarepta’s patents and take government ownership will most certainly go unheeded as that would cause every other orphan drug manufacturer to immediately discontinue any further financial risk for fear of similar confiscation.

There are, however, opportunity costs beyond the financial. Some would say that the FDA approved eteplirsen with extremely flimsy data, as less than 10 boys showed borderline promising results when the drug was approved in November 2016. That FDA approval allowed Sarepta to survive as a company. Per the editorial board at the Wall Street Journal(subscription needed):

“But if FDA had cashiered that therapy, Sarepta would have lacked the resources to continue its research and testing to treat Duchenne and develop what may be an even better drug. If eteplirsen had failed to get approval, dollars and brain power would inevitably have flowed toward treating other diseases with more promise of success. FDA has tremendous influence over private investment.”

Indeed Sarepta has new genetic treatments in the pipeline which reportedly do provide increased levels of dystrophin, even for RNA patterns beyond what eteplirsen can presently correct. Have the ends justified the means? Presently, for DMD patients, despite the $300K yearly price tag for eteplirsen, that answer may be – yes. Sadly, there are no other currently functional treatment options for DMD – yet.

From a public health standpoint (and a public funding standpoint), orphan drugs for treatment of small population diseases like DMD are non-starters. Is the only answer to provide the opportunity for great financial reward to encourage individuals to assume all of the private risk?

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