An Open Label, Single Cohort Study to Assess How Nusinersen Is Processed Using the ThecaFlex DRx System Compared to Lumbar Puncture in Participants With Spinal Muscular Atrophy

What this Trial Is About

Researchers are evaluating how the body processes nusinersen, a drug used for spinal muscular atrophy (SMA), when it is delivered through an investigational implantable device called the ThecaFlex DRx System versus the standard lumbar puncture method. This Phase 1, open-label study aims to understand the drug's concentration in the blood after dosing with each delivery method. Participants in the PIERRE study, who have SMA, may join this PIERRE-PK study to help answer these questions. Participants will receive a 12 milligram dose of nusinersen by lumbar puncture first, followed by implantation of the ThecaFlex DRx System. After the device is implanted, participants will receive the same 12 milligram dose of nusinersen through the device. Blood samples will be collected before and after each dose to measure drug levels, with a final sample taken 24 hours after dosing. The study treatments and device implantation are part of the PIERRE and PIERRE-PK studies combined. The study involves a screening period of up to 30 days, which may overlap with the PIERRE study screening. Each participant's involvement in the PIERRE-PK study lasts about five months, overlapping with their first five months in the PIERRE study. Researchers will monitor blood samples for the highest drug concentration and overall exposure during the first 24 hours after dosing to understand how nusinersen behaves in the body with each delivery method.

A Study to Find Out How Nusinersen is Processed in the Body When Given Through the ThecaFlex DRx™ System in Adult and Pediatric Participants With Spinal Muscular Atrophy (PIERRE-PK)