Summit Therapeutics PLC (ADR) (NASDAQ:SMMT) Is Hot On Sarepta Therapeutics Inc (NASDAQ:SRPT)’s DMD Tail

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Duchenne’s Muscular Dystrophy (DMD) is a hot topic right now. The furor surrounding Sarepta Therapeutics Inc (NASDAQ:SRPT)’s Eteplirsen, which just picked up a delay response from the FDA, and the announcement regarding BioMarin Pharmaceutical Inc.(NASDAQ:BMRN)’s now discontinued candidate are grabbing headlines, but these two companies are far from exclusive in the space.  Summit Therapeutics PLC (ADR) (NASDAQ:SMMT) just announced the first patient enrolled in a phase II for its lead candidate Ezutromid, and expects to offer up some interim (24 week) data as soon as January next year.

As the trials get going, and move towards reporting come January, we will likely see some interim releases alluding to efficacy and tolerability. Each of these updates has the potential to inject some upside momentum into the company’s market capitalization, making it an intriguing one to watch as we move forward. So, with this in mind, here’s some detail on the drug in question, and a look at whether Summit can compete with Sarepta’s offering if both get a green light.

First then, the drug. DMD is a condition that derives from a mutation in the gene that codes for dystrophin. Dystrophin is a protein that plays a vital role in the structural integrity of muscles, and when it is not produced (or is dysfunctional, depending on the mutation in question) it can cause the muscle wastage that is the hallmark of DMD.

As it turns out, we’ve got another protein called utrophin, which is structurally similar to dystrophin, and there is mounting evidence that it can mimic the latter functionally. Ezutromid is what’s called a utrophin modulator – it upregulates the production and release of utrophin. This utrophin (theoretically) then gets to work structurally reinforcing muscles and reversing the effect of long term dysfunctional dystrophin.

So what’s the difference between this and Eteplirsen, and what does this difference mean for Summit going forward? DMD is caused by a host of different mutations, all of which have the same end result – dystrophin that doesn’t work. Sarepta’s Eteplirsen targets a number of these mutations, accounting for about 12-13% of the DMD patient population, and uses a gene editing technique to attempt to produce a sort of semi functional dystrophin alternative. In contrast, Ezutromid doesn’t have any effect on the dysfunctional dystrophin genes, so it can be used to treat the entire DMD population, if it gets an agency nod.

So what is the status of the trial, and what are we looking out for come data release?

Well, it’s a phase II that is extending into the US, out of the UK, ad it’s set up as a proof of concept study. Preclinical and a phase I that looked at tolerability suggested some clinical evidence, but neither were wide enough to say for sure whether the drug works. This proof of concept trial is essentially trying to show that the drug is absorbed and taken up correctly, as well as attempting to establish a clinical benefit from the perspective of improved muscle function. The primary endpoint relates to a change from a pre-established baseline in magnetic resonance imaging parameters, looking at fat infiltration and inflammation of the leg muscles. Secondary (exploratory) endpoints include the six-minute walk distance, which is now a famous measuring stick based on the high profile of the Eteplirsen study, and what’s called the North Star Ambulatory Assessment as well as patient reported outcomes.

The trial is a 48-week trial, and the January 2017 data release will only address the first 24 weeks of treatment, so we are probably looking at topline some point during the second or third quarter of 2017.

So what’s the takeaway here? Well, Sarepta is grabbing all the headlines with Eteplirsen, but Summit is hot on the company’s trail with its own DMD candidate, and has the potential to target a much wider patient population if it gets approval. There’s still plenty of time to go before any sort of NDA filing, but this doesn’t mean data can’t provide interim catalysts. The just kicked off phase II is one such opportunity for a number of catalysts, making the trial (and the company) one to watch throughout the latter half of 2016.

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