Sarepta steps up DMD dealmaking
- Sarepta Therapeutics on Tuesday inked a licensing deal with U.K.-based Summit Therapeutics, paying $40 million upfront for European rights to Summit's experimental drug for Duchenne muscular dystrophy (DMD), along with a related pipeline.
- Summit's lead candidate, known as ezutromid, is designed to boost production of utrophin, a protein similar in function to the dystrophin protein missing in DMD patients. Summit believes ezutromid could potentially be disease-modifying for all DMD patients, whereas Sarepta's newly approved Exondys 51 only works in an estimated 13% of the patient population.
- Sarepta has been busy since winning a much-delayed green light from the FDA for Exondys, signing a joint research deal with Catabasis Therapeutics for a DMD combo late last month.
Sarepta has laid out a long chain of potentially lucrative milestones for Summit, including $42 million in development milestones for ezutromid. Over half of that will come due following dosing of the last patient in Summit's Phase 2 trial of ezutromid.
Other regulatory and sales milestones further down the line for ezutromid and Summit's pipeline could bring total deal value as high as $852 million, according to a regulatory filing with the Securities and Exchange Commission.
Data in support of ezutromid's efficacy has so far come from studies done in human muscle cells and in mice. But Summit is already recruiting patients at U.K. sites for its 40-patient Phase 2 study and plans to open recruiting at U.S. sites shortly, according to company CEO Glyn Edwards.
Summit, and now Sarepta, could have a clearer picture of ezutromid's efficacy as early as mid-next year.
"The first data which is of interest will be from biopsies taken at 24 weeks. We expect to announce that data sometime around the middle of next year, so either Q2 or Q3 of next year," Edwards said in an interview with BioPharma Dive.
The study will also measure biopsies taken at 48 weeks and compare both 24- and 48-week data to baseline biopsies.
Summit is hopeful ezutromid could be disease-modifying in all DMD patients, regardless of genetic mutations. The drug is aimed at keeping production of utrophin protein — similar in function to dystrophin — turned on in muscle cells. Usually, utrophin production kicks off after muscle cell formation and is replaced by dystrophin. That doesn't happen in DMD patients, leading to inflammation and muscle degradation.
Ezutromid could also work in complement with other DMD drugs, but Edwards emphasized Summit was focused on winning approval for ezutromid first.
"Our initial thrust is very much to show single agent activity and get a single agent approval. But I'm sure once we have done that, then we will be looking to do combination studies not just with Exondys 51 but with other treatments," Edwards said.
While the licensing discussions for ezutromid are relatively recent, Sarepta and Summit have collaborated in the past on biomarkers and biopsy methods.
Asked if the controversy surrounding the Food and Drug Administration's approval of Exondys 51 has changed Summit's approach, Edwards said the back-and-forth and delays reinforced the need to present well-recognized data to regulators.
"Our aim is to show the drug works in the right way so that we can go to the European regulators and the FDA and that it will be not a controversial decision to approve them," Edwards said. "I think the whole Sarepta experience has just confirmed exactly what people want to see in terms of surrogate endpoints in this area."
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