There were not enough data at 6 months to predict expanded disability status scale (EDSS) improvements after treatment.
ATA188, Atara Biotherapeutics’ Epstein-Barr Virus (EBV)-targeting multiple sclerosis (MS) cell therapy did not show significant improvements in the interim analysis of phase 2 EMBOLD trial (NCT03283826).1
The study will continue, without sample size adjustment based on the Independent Data and Safety Monitoring (DSM) Committee’s recommendation after reviewing efficacy, safety, and biomarker data from an interim analysis.
“Following the EMBOLD IA, we are proceeding with the IDSMC’s recommendation that the study continue to completion without sample size adjustment,” Jakob Dupont, MD, Head of Global Research & Development, Atara Biotherapeutics, said in a statement.1 “After reviewing the clinical and safety data available at the data cut-off, the IDSMC did not highlight any safety concerns in the ongoing study. We are pleased to have completed the target enrollment for the EMBOLD study and look forward to sharing the topline results as planned at an appropriate forum in October 2023.”
The interim analysis was primarily assessing expanded disability status scale (EDSS) improvement at 6 months and overall safety from the 34 evaluable patients at 6 months and 15 evaluable patients at 12 months. Other clinical data including magnetization transfer ratio (MTR) biomarker data were also assessed. Previously, data from 24 patients in the open-label phase 1 study showed some EDSS improvement at 12 months.
The DSM decided that there were not sufficient data at 6 months to be able to assess the predictive value of 6-month EDSS improvement for 12-month EDSS improvement at the 6-month endpoint and the 6-month endpoint is an inaccurate measure. The study will continue unadjusted until 12-month endpoints can be assessed.
Since the interim analysis, the study has exceeded its 80-patients enrollment target. Final data on 12-month EDSS improvements are expected in October 2023. The therapy has been well-tolerated so far.
“We look forward to completing the EMBOLD study as we aspire to demonstrate a potentially transformative profile for ATA188 in patients with progressive MS who have high unmet need and limited options,” Pascal Touchon, President and chief executive officer, Atara, added to the statement.1
Atara’s approach to treating MS was supported in February 2022 with the publication of a paper that elucidated the relationship between MS and EBV in Science.2 The paper revealed the high prevalence of EBV infections associated with MS. CGTLive previously spoke with Dupont in an interview about the implications of this research.
“Over the course of the last 5 years, the data for this relationship between Epstein Barr Virus and multiple sclerosis has become stronger and stronger. I would say that's from academic groups working on this question of the relationship between EBV and MS, but also some of the work that we've generated in the clinic with our physicians and patient collaborators to determine whether or not an EBV-directed therapy can make a real difference for patients with MS,” Dupont said.