Positive interim results announced in study of therapeutic for Becker muscular dystrophy

Edgewise Therapeutics Inc. announced positive 4-month interim results from the ongoing ARCH study of investigational, orally administered EDG-5506 for the treatment of Becker muscular dystrophy in adults.

EDG-5506 is a small molecule myosin modulator designed to protect injury-susceptible fast skeletal muscle fibers in dystrophinopathies, including Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), per a release issued by Edgewise.

The 12 adults with BMD enrolled in the ARCH study were dose escalated to daily 15 mg oral doses of EDG-5506 at night after having initially received a 10 mg dose during the first 2 months of the study. At 4 months, plasma pharmacokinetics reached the target exposures observed in the phase 1b study, in which BMD participants were dosed with 20 mg EDG-5506 once-daily for 2 weeks.

According to the release, EDG-5506 was well-tolerated in all participants with no discontinuations or dose reductions. The most common adverse events observed to date were dizziness, drowsiness and headache. All eligible patients have subsequently been dose escalated to 20 mg daily as per protocol.

Treatment with EDG-5506 led to a significant decrease in key biomarkers of muscle damage when assessed by laboratory assays, the company stated. Specifically, creatine kinase (CK) and fast skeletal muscle troponin I were reduced by an average of 29% and 74%, respectively, after 4 months. While CK reductions were sustained and in line with observations made at 2 months, mean fast skeletal muscle troponin I levels decreased with continued exposure to EDG-5506.

Like observations made after 2 months, both CK and fast skeletal muscle troponin I were significantly decreased in the context of typical everyday activity levels as measured with a pedometer, according to the release.

“Those with BMD have no approved options to treat their condition,” Joanne Donovan, MD, PhD, chief medical officer at Edgewise, said in the release. “We continue to be encouraged by EDG-5506’s safety profile, and these interim 4-month data allow us to make some critical decisions on how to potentially accelerate our clinical programs in BMD and DMD.”

Further, North Star Ambulatory Assessment (NSAA) scale measurements increased by an average of 1.17 points after 4 months of EDG-5506, compared with pre-treatment baseline levels, and nine of 12 participants demonstrated either functional improvement or no decline on NSAA compared with baseline.

“We appreciate the individuals with BMD who are participating in the ARCH open-label study,” Kevin Koch, PhD, president and CEO at Edgewise, said in the release. “These early NSAA results, along with the steep decline in biomarkers of muscle damage, are very encouraging and highlight EDG-5506’s potential to alter the course of the disease.”