Phase 1/2 Study to Evaluate the Safety and Efficacy of ATA188 in Subjects With Progressive Multiple Sclerosis

Summary

Participation Requirements

Description

This is a multicenter, 2 part study in adult participants with progressive forms of MS (PPMS/SPMS) with an open-label, single-arm, sequential dose-escalation period (Part 1) and a double-blind, randomized, placebo-controlled dose-expansion period (Part 2) and open-label extension (OLE) period. Part ...

This is a multicenter, 2 part study in adult participants with progressive forms of MS (PPMS/SPMS) with an open-label, single-arm, sequential dose-escalation period (Part 1) and a double-blind, randomized, placebo-controlled dose-expansion period (Part 2) and open-label extension (OLE) period. Part 2 and the OLE will be initiated at the sponsor's discretion based on a review of data from the dose-escalation cohorts. This study will evaluate the safety and efficacy of ATA188 administered by intravenous (IV) infusion. ATA188 will be selected for each participant based on matching at least 2 human leukocyte antigen (HLA) alleles shared between ATA188 and the participant including at least 1 HLA-restricting allele. In Part 1, participants will receive 2 cycles of ATA188 and will enter 12 months follow-up period after the last dose of ATA188. Participants who have completed at least the first year of the dose-escalation period and are still active in the study may be allowed to enter in OLE period and will receive the same RP2D assigned to Part 2 participants at the time of the Part 1 participant's first dose in each year of the OLE. In OLE period, participants will receive 1 cycle of ATA188 treatment every 12 months (Q12M) for up to 4 years (ie, Years 2 to 5). Otherwise, end of study (EOS) visit will be conducted at 24 months after Cycle 1 Day 1. In Part 2, participants will be randomized in 1:1 ratio to receive ATA188 at the RP2D or matching placebo, stratified by progressive MS diagnosis (PPMS vs SPMS) and any prior exposure to anti-CD20 therapy (yes vs no). Initially 80 participants will be randomized to ATA188 or placebo. Randomization of additional participants into the study will be based on the results of the interim analysis. Participants will receive 2 cycles of ATA188 at the RP2D or matching placebo and will be followed for at least 12 months after the first dose of study drug (ie, Year 1). In second year (Year 2), participants who received placebo in Year 1 will receive 2 cycles of ATA188 at the RP2D assigned at randomization and participants who received ATA188 at the RP2D in Year 1 will receive 1 cycle of ATA188 (at the RP2D assigned at randomization) and 1 cycle of placebo. Participants who complete Year 2 will enter in OLE period to receive ATA188 Q12M for up to 3 years (ie, Years 3 to 5) at the RP2D that was last selected by the sponsor for Part 2. The end of study visit will be scheduled at 5 years (60 months) after the first dose of study drug (ie, Cycle 1 Day 1). Part 1 of the study recruitment has completed, Part 2 continues to recruit participants.

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