Atara Biotherapeutics Announces Primary Analysis Data from Phase 2 EMBOLD Clinical Trial of ATA188 in Non-Active Progressive Multiple Sclerosis

Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a leader in T-cell immunotherapy, leveraging its novel allogeneic Epstein-Barr virus (EBV) T-cell platform to develop transformative therapies for patients with cancer and autoimmune diseases, today announced primary analysis data from its Phase 2 EMBOLD study of ATA188 in non-active progressive multiple sclerosis (PMS). The study did not meet the primary endpoint of confirmed disability improvement (CDI) by expanded disability status scale (EDSS) at 12 months compared to placebo. In addition, fluid and imaging biomarkers did not provide further supportive evidence.

"We are surprised and deeply disappointed with the results of EMBOLD, particularly for the MS patient community which is in urgent need of new treatment options. We are grateful to the patients and investigators who participated in the study, and to colleagues at Atara for their steadfast work,” said Pascal Touchon, President and Chief Executive Officer of Atara. “We are further evaluating the EMBOLD data as we continue to believe in the critical role EBV plays in MS pathogenesis, however we anticipate stopping the study as no treatment benefit was observed.”

Preliminary safety data showed there were no new safety signals in the EMBOLD study, reinforcing the favorable safety profile observed with ATA188 to date.

Atara is actively reviewing the totality of the data, including a 6 percent disability improvement in the treatment arm compared to 33 percent disability improvement observed in the Phase 1 study, in addition to identifying the factors related to a substantially greater than expected placebo rate of 16 percent for CDI at 12 months compared with an expected rate of 4-6 percent in non-active PMS patients. These evaluations will help Atara determine the next steps for the program.

“Looking ahead, we maintain our strong conviction in the potential of our pipeline reinforced by the first ever regulatory approval of an allogeneic T-cell immunotherapy, EBVALLO^TM, in Europe,” Dr. Touchon continued. “Following anticipated additional payments and significant double-digit royalties from the recently expanded tab-cel partnership with Pierre Fabre, we are currently well positioned with a cash runway well beyond upcoming milestones, including pre-clinical data for ATA3431 at ASH in December, preliminary clinical data from our Phase 1 study of ATA3219 in relapsed/refractory B-cell non-Hodgkin’s lymphoma anticipated in the second half of 2024, and expanding ATA3219 development into autoimmune disease.”