Myostatin Modulation in Spinal Muscular Atrophy: A Systematic Review of Preclinical and Clinical Evidence.

Spinal Muscular Atrophy (SMA) is a genetic disorder characterized by the progressive loss of motor neurons and consequent muscle atrophy. Although SMN-targeted therapies have significantly improved survival and motor outcomes, residual muscle weakness remains a major clinical challenge, particularly in patients treated later in the disease course. Myostatin, a potent negative regulator of skeletal muscle mass, has emerged as a promising therapeutic target to address this gap. This review summarizes the preclinical and clinical evidence supporting the modulation of the myostatin pathway in SMA. Preclinical studies have demonstrated that inhibiting myostatin, especially when combined with SMN-enhancing agents, can increase muscle mass, improve motor function, and enhance neuromuscular connectivity in SMA mouse models. These findings provide a strong rationale for translating myostatin inhibition into clinical practice as an adjunctive strategy. Early clinical trials investigating myostatin inhibitors have shown favorable safety profiles and preliminary signs of target engagement. However, large-scale trials have yet to demonstrate widespread, robust efficacy across diverse patient populations. Despite this, myostatin pathway inhibition remains a compelling approach, particularly when integrated into broader treatment paradigms aimed at enhancing motor unit stability and function in individuals with SMA. Further clinical research is essential to validate efficacy, determine optimal timing, and define the patient subgroups most likely to benefit from myostatin-targeted therapies.