Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disorder caused by deletions or mutations in the SMN1 gene, leading to reduced SMN protein levels. This results in motor neuron degeneration, causing muscle weakness and wasting. SMA can lead to difficulties with movement, breathing, and swallowing. Despite available SMN-upregulating treatments, many patients continue to experience muscle weakness and fatigue.

The Sparkle study is designed to evaluate how an investigational study drug* may work (also known as efficacy), and how safe it is for use in children and teenagers living with SMA. This study will evaluate the investigational study drug compared with placebo.

*The investigational study drug, adimanebart, is not approved by any regulatory agency for use in patients living with SMA, as efficacy and safety have not been established.

Your child may be eligible to participate if they are:

• Between 5 and less than 18 years of age
• Diagnosed with 5q-SMA
• Able to walk at least 50 meters without walking aids
• Currently receiving a stable SMA treatment regimen (nusinersen or risdiplam) and/or have a history of onasemnogene abeparvovec treatment

Additional criteria to participate apply, which the study doctor will discuss with you. 

If your child joins the study, they will participate for up to 3 years (148 weeks). During this time, they may need to visit the study center approximately 38 times.
The study consists of:

• Screening period: up to 4 weeks
• Main double-blinded period: 24 weeks
  (your child may receive placebo OR investigational study drug during this period)
• Active-treatment extension period: up to 100 weeks
  (your child will receive investigational study drug during this period)
• Safety follow-up period: 20 weeks after the last dose

The investigational study drug and placebo are given through an infusion into a vein in the arm (intravenously).