STAT+: Capricor Therapeutics’ Duchenne treatment is heading for an FDA rejection

Duchenne muscular dystrophy (DMD) is traditionally considered a primary muscle disorder, and AAV-mediated microdystrophin gene therapies have been successful in maintaining muscle structure. However, their effectiveness in improving functional results remains suboptimal. The researchers hypothesized that this limitation might be due to an overlooked problem in the peripheral nerve.

They discovered that the mdx mouse model exhibits a peripheral axonopathy, separate from muscle degeneration. Through single-nucleus RNA sequencing and structural assessments, they found an active denervation process and a significant deficiency in neural repair mechanisms. Crucially, they discovered that the complete-length dystrophin isoform Dp427c is expressed in healthy peripheral nerves, mirroring the cytoskeletal organization and concentrating at sites of high mechanical stress, like Schmidt-Lanterman incisures and Nodes of Ranvier.

In its absence, nerves of mdx mice experience a vital structural support, resulting in localized structural failure. Moreover, they demonstrated that muscle-specific microdystrophin gene therapy preserves the sarcolemmal integrity but fails to restore nerve-muscle connection or rectify neurotransmission problems. These discoveries revolutionize the perception of DMD as a comprehensive motor unit condition, highlighting the critical importance of adopting integrated therapeutic approaches that target both muscle and peripheral nervous system.