Summit Therapeutics Publishes Preclinical Data on Disease-Modifying Potential of Utrophin Modulation in DMD

  • Publication in Human Molecular Genetics supports utrophin modulation as mechanism to treat DMD regardless of mutation status

OXFORD, United Kingdom, July 13, 2015 (GLOBE NEWSWIRE) -- Summit Therapeutics plc (NASDAQ:SMMT) (AIM:SUMM), the drug discovery and development company advancing therapies for Duchenne muscular dystrophy ('DMD') and C. difficile infection, today announced the publication of preclinical data on the disease-modifying potential of utrophin modulation in the treatment of DMD.

Upon modulation of utrophin protein with the second generation utrophin modulator SMT022357, in vivo models of DMD showed significantly improved muscle stability and a marked reduction of muscle regeneration, necrosis and fibrosis, the hallmark of DMD pathology. Interestingly, researchers found that utrophin was expressed across the entire length of the muscle fibre, likely contributing to its ability to significantly reduce disease progression in animal models. The data were published in the August 1, 2015 issue of Human Molecular Genetics.

"These data strongly support utrophin modulation as a potentially valuable mechanism to treat DMD and highlight the importance of the continued development of second-generation, orally available utrophin modulator candidates," said Professor Dame Kay E. Davies of the University of Oxford. "There is tremendous therapeutic potential for utrophin modulation in this devastating disease because there is currently no approved disease modifying therapy applicable to all patients with DMD and many other candidates in clinical development are restricted to a single mutation."

Utrophin is structurally and functionally similar to dystrophin, the protein which is lacking in boys with DMD, and is normally present during muscle development and repair. By modifying utrophin to be continuously produced in boys with DMD, this potentially disease-modifying approach could circumvent the need for dystrophin in all patients with this devastating disease. Summit is currently in Phase 1b clinical studies with SMT C1100, a first-generation utrophin modulator. The paper, "Second-generation compound for the modulation of utrophin in the therapy of DMD," describes the significant disease-modifying potential of SMT022357, a structurally related compound to SMT C1100, which has enhanced pharmaceutical properties.

In the reported study, SMT022357 treatment for five weeks resulted in increased utrophin expression, localized along the entire length of the muscle fibre membrane in both slow- and fast-twitch muscles. This addressed the primary cause of fibre degeneration and increased muscle stability in hind-limb muscles of the mdx mouse, which resulted in reduced regeneration and necrosis, enhanced protection of the muscle against contraction-induced damage and improved muscle function. Utrophin expression in the heart and diaphragm is highly desirable in DMD as loss of function in these organs is life-limiting in DMD. Treatment with SMT022357 resulted in significant increases in utrophin expression in both the heart and diaphragm. Notably SMT022357 treatment resulted in reduced fibrosis in the diaphragm, a significant observation due to the disease pathology in the diaphragm of the mdx model closely resembling that of DMD patients. These data suggest that SMT022357 results in significant improvement in the pathology of DMD and could represent a disease-modifying therapeutic strategy for all patients with DMD.

The paper was authored by Simon Guiraud, Sarah E. Squire, Benjamin Edwards, Huijia Chen, David T. Burns, Nandini Shah, Arran Babbs, Stephen G. Davies, Graham M. Wynne, Angela J. Russell and Kay E. Davies of the University of Oxford, and David Elsey, Francis X. Wilson and Jon M. Tinsley of Summit Therapeutics (reference: Hum. Mol. Genet. (2015) 24 (15): 4212-4224).

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About DMD and Utrophin Modulation

DMD is a progressive muscle wasting disease that affects around 50,000 boys in the developed world. The disease is caused by different genetic faults in the gene that encodes dystrophin, a protein that is essential for the healthy function of all muscles. There is currently no cure for DMD and life expectancy is into the late twenties. Utrophin protein is functionally and structurally similar to dystrophin. In preclinical studies, the continued expression of utrophin has meaningful, positive effect on muscle performance. Utrophin modulation has the potential to slow down or even stop the progression of DMD, regardless of the underlying dystrophin mutation. It is also expected that utrophin modulation could potentially be complementary to other therapeutic approaches for DMD.

About Summit Therapeutics

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

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Source:Summit Therapeutics plc