Study of an Intrathecal Port and Catheter System for Subjects With Spinal Muscular Atrophy

This is a multicenter, multi-national, prospective, non-randomized, single arm, group sequential design, pivotal clinical investigation (device exemption study) to assess the safety and performance of the ThecaFlex DRx™ System in subjects with SMA. The subject population will include subjects aged ≥ 3 years with SMA who are considered candidates for intrathecal port and catheter implantation because they require chronic, bolus intrathecal administration of necessary therapy, and who meet all the inclusion/exclusion criteria for the clinical investigation. After a screening period of up to 200 days, all enrolled subjects will undergo implantation of the investigational device (ThecaFlex DRx™ System) and will be followed for 12 months after receiving the implant. In agreement with the nusinersen dosing information, the treatment frequency will be adapted for non-naïve and naïve subjects: Subjects who are not naïve to nusinersen should have nusinersen maintenance doses administered via the implant every 4 months (i.e., 4, 8, and 12 months after their last nusinersen dose, before enrollment in the clinical investigation). Subjects who are naïve to nusinersen will have their first three loading doses administered via the implant at 14-day intervals. The fourth loading dose should be administered 30 days after the third dose. A maintenance dose should be administered once every 4 months thereafter within the 12 months post-implantation. A DMC and Clinical Events Committee (CEC), independent of each other and the Sponsor, will be used to perform ongoing consistent adjudication of events related to the safety throughout the entire duration of the clinical investigation and to periodically review data that relate to the safety of the study. The clinical investigation will enroll 90 subjects. The clinical investigation incorporates a lead-in phase which consists of 10 subjects enrolled, implanted, and followed for 30-days. Enrollment for the lead-in phase is expected to take approximately 6 to 9 months, at which point the Data Monitoring Committee (DMC) will review the data for safety and approve continuation of enrollment. The second phase of enrollment is expected to take approximately 12 to 15 months. Individual subjects are anticipated to be enrolled in the clinical investigation for approximately 37 months. The total duration of this clinical investigation is estimated to be approximately 60 months.