To evaluate patient treatment effects beyond TOPAZ trial endpoint measures to provide a deeper understanding of the potential benefit of apitegromab.

SMA is caused by deletion or mutation in SMN1 gene and is characterized by motor neuron deterioration that contributes to progressive muscle weakness and loss of motor function. Current SMN treatments have shown improvements in motor function; however, limitations remain that contribute to unmet needs. In a Phase 2 trial (TOPAZ, NCT03921528), we have reported safety and efficacy of apitegromab, a selective myostatin inhibitor, in patients with Types 2/3 SMA. HFMSE and RHS scales were used to evaluate efficacy.

This qualitative, cross-sectional study aimed to gain insights into the impact of SMA and potential treatment benefits based on patient’s/caregiver’s perceptions of SMA and experience with treatment during the TOPAZ trial through 24 months. A subset of 15 patients were invited to participate in a 2 hour semi-structured interview about their experience with SMA and perceptions of meaningful treatment benefit during the trial. Treatment effects observed during the trial were compared to pre-treatment signs and symptoms.

Twelve patients/caregivers were interviewed. Participants reported substantial burden in signs and symptoms associated with SMA including muscle weakness, fatigue, problems with balance, respiratory problems, and bowel difficulties. They also reported impacts of SMA on physical function, dependency, daily activities, and social activities. Improvements in signs, symptoms and impacts of SMA after treatment will be reported.

The symptoms and impacts of living with SMA as reported by 12 patients/caregivers provided insight related to meaningful treatment benefits experienced while receiving apitegromab during the TOPAZ trial, particularly around activities of daily living, fatigue, muscle weakness, physical functioning, independence, and balance. These data provide supplemental insights beyond what may be captured in a standardized questionnaire and give insight to the holistic improvement in the patient’s quality of life.