Data from an ongoing study of an allogeneic EBV T-cell immunotherapy (ATA188; Atara Biotherapeutics, South San Francisco, CA) showed safety and efficacy for the treatment of progressive multiple sclerosis (PMS). Composite scales of clinical outcome and of sustained disability improvement (SDI) were assessed in participants receiving 1 of 4 escalating doses of the T-cell immunotherapy. Data from cohorts 1 to 4 at 6 months (n=24) and cohorts 1 to 3 at 12 months (n=17) were presented at the European Academy of Neurology Virtual Congress 2020. The SDI was reported at 6 months and 12 months and was defined as a composite of clinically significant improvement in expanded disability satus scale (EDSS) or timed 25-foot walk (T25FW), confirmed at consecutive measures.
Dr. Manher (AJ) Joshi, head of Clinical Development and chief medical officer at Atara Biotherapeutics, said, “We studied ATA188 in 4 dose-escalating cohorts with 6 participants per cohort. These data demonstrate that ATA188 was well-tolerated across all 4 dose cohorts there was a higher proportion of participants in each cohort showing improvements as the dose increased, and for all patients with 12 month data, SDI seen at 6 months was maintained at 12 months.” Dr. Joshi also noted this potential treatment is different from existing options, in that it is focused on the core pathologic cells involved in both the relapsing and progressive forms of MS.
All participants who achieved SDI at 6 months, maintained disability improvement through 12 months. Additionally, a dose-related increase in the number of participants with SDI was observed. . For cohorts 1 and 2, each cohort had 1 participant that achieved SDI at 6 months with maintained improvement at 12 months, and for cohort 3 there were 2 participants with SDI at 6 months, with maintained improvement at 12 months. Also, for cohort 3, a third participant achieved SDI at 12 months. For cohort 4, there were 2 participants with SDI at 6 months, neither of whom has yet reached the 12-month time point.
No dose-limiting and no fatal adverse events have been reported. Rhinorrhea is the only treatment-related event that occurred in more than one subject (experienced by two patients). Additionally, treatment with ATA188 shows no clinically meaningful effect on cytokine production post-infusion.