Summit’s DMD drug cuts muscle inflammation in POC trial

Duchenne muscular dystrophy
Histopathology of gastrocnemius muscle from a DMD patient (Dr. Edwin P. Ewing, Jr./Public domain)

Summit Therapeutics has posted further data from the ongoing phase 2 trial of ezutromid. The latest analysis links the utrophin modulator to a statistically significant decline in muscle inflammation in boys with Duchenne muscular dystrophy (DMD).

Oxford, U.K.-based Summit generated the data on muscle inflammation by measuring MRI transverse relaxation time T2 (MRS-T2). The technique quantifies the breakdown and inflammation of muscle, making it a useful tool for assessing the progression of DMD. MRS-T2 values rise as DMD progresses but can be brought down by steroids.

The Summit data suggest ezutromid may drive reductions in MRS-T2 beyond those achieved by the use of steroids alone. All 38 participants in the proof-of-concept trial were on stable steroid regimes. After 24 weeks of twice-daily ezutromid doses, MRS-T2 decreased by 0.861 milliseconds, on average.

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Summit needs to do more work to show whether that finding and others generated to date have a meaningful effect on the lives of people with DMD. But some observers see the data gathered so far as a source of encouragement.

“The decrease in MRS-T2 seen in PhaseOut DMD is encouraging and suggests ezutromid is having a positive effect on muscle health,” H. Lee Sweeney, director of the Myology Institute at the University of Florida, said in a statement. “These data could be an early indication that these patients are experiencing a decrease in disease severity and highlight ezutromid's potential as a disease modifying treatment.”

RELEASE: Summit Therapeutics unveils encouraging early data for Duchenne drug

Publication of the data on MRS-T2 comes a month after Summit shared a look at other endpoints. That earlier data drop linked ezutromid to a decline in muscle damage and an uptick in utrophin protein intensity levels. Together with the muscle inflammation readout, the data form the backbone of early efforts to show ezutromid is a disease-modifying therapy suited for use by all DMD patients.

Summit is short of making that argument conclusively. The next step is to post data from the full 48-week trial. Beyond that, Summit plans to move ezutromid into a pivotal study. 

The progress of those studies will be closely watched by the DMD community and Sarepta, which celebrated the approval of its drug targeting the disease by striking a deal with Summit. Sarepta paid $40 million upfront and committed to more than $500 million in milestones to secure the rights to ezutromid in Europe and some other markets.