Industry Partner News: Summit Therapeutics Completes 48 Weeks of Dosing in PhaseOut DMD

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Summit Completes Dosing of Ezutromid in PhaseOut DMD Clinical Trial
Top-line Data On-track to be Reported During Q3 2018

Oxford, UK, and Cambridge, MA, US, 19 April 2018 – Summit Therapeutics plc (NASDAQ: SMMT, AIM: SUMM) announces the completion of ezutromid dosing in patients with Duchenne muscular dystrophy (‘DMD’) for the full 48-week PhaseOut DMD clinical trial. Top-line data from the full trial continue to be expected in the third quarter of 2018.

“We believe the early improvements seen in muscle health in the interim data from PhaseOut DMD indicate ezutromid is reducing DMD disease severity. In the full trial results, we aim to see continued utrophin modulation and sustained changes in magnetic resonance parameters,” said Dr David Roblin, Chief Medical Officer and President of R&D of Summit. “These results, if positive, could form the basis of a regulatory filing of ezutromid, bringing this universal treatment to patients more rapidly.” 

PhaseOut DMD is a Phase 2 open-label, multi-centre trial of the Company’s utrophin modulator, ezutromid, in patients with DMD. Previously announced 24-week interim data from PhaseOut DMD showed evidence of activity across three different measures. Specifically, ezutromid:

  • Maintained the production of utrophin, a naturally occurring protein that can potentially substitute for dystrophin, as measured by muscle biopsy;
  • Significantly and meaningfully reduced muscle damage, as measured by muscle biopsy; and
  • Significantly reduced muscle inflammation, as measured by magnetic resonance.

About Utrophin Modulation in DMD

DMD is the most common and severe form of muscular dystrophy, impacting 50,000 patients in the developed world alone. DMD is caused by the lack of dystrophin, a protein that maintains healthy muscle function. The absence of dystrophin results in a catastrophic cycle of muscle damage and repair that leads to progressive loss of functional ability and ultimately in premature death.

Utrophin and dystrophin play a similar role in maintaining muscle function, but do so at different times. Utrophin plays this role when new muscle fibres are being formed, or when damaged fibres are being repaired, but then switches off to make way for dystrophin to perform this role in mature muscle fibres. Since patients with DMD are not able to produce dystrophin, a cycle of muscle damage and repair occurs, which eventually leads to muscle fibre failure. Utrophin modulation aims to address the root cause of DMD by maintaining the production of utrophin to substitute for the missing dystrophin. The presence of utrophin in mature muscle fibres could break the cycle of damage and repair and ultimately slow, or even stop, disease progression. Importantly, this approach has the potential to treat all patients with DMD regardless of their underlying dystrophin gene mutation.

The Company’s lead utrophin modulator, ezutromid, is an orally administered, small molecule drug. DMD is an orphan disease, and the US Food and Drug Administration (‘FDA’) and the European Medicines Agency have granted orphan drug status to ezutromid. Orphan drugs receive a number of benefits including additional regulatory support and a period of market exclusivity following approval. In addition, ezutromid has been granted Fast Track designation and Rare Pediatric Disease designation by the FDA. 

About PhaseOut DMD

PhaseOut DMD is an open-label, multi-centre trial that has enrolled 40 patients in the US and UK, aged from their fifth to their tenth birthdays. PhaseOut DMD is 48 weeks in length after which patients have the option of enrolling into an extension phase and continuing to be dosed with ezutromid. The primary endpoint is the change from baseline in magnetic resonance parameters related to the leg muscles. Biopsy measures evaluating utrophin and muscle damage are included as secondary endpoints. Exploratory endpoints include the six-minute walk distance, the North Star Ambulatory Assessment and patient reported outcomes.

About Summit Therapeutics

Summit is a biopharmaceutical company focused on the discovery, development and commercialisation of novel medicines for indications for which there are no existing or only inadequate therapies. Summit is conducting clinical programmes focused on the genetic disease Duchenne muscular dystrophy and the infectious disease C. difficile infection. Further information is available at www.summitplc.com and Summit can be followed on Twitter (@summitplc).