ATA188 for multiple sclerosis
Last updated Aug. 18, 2025, by Lindsey Shapiro, PhD
Fact-checked by Inês Martins, PhD
What is ATA188 for MS?
ATA188 is a cell-based therapy that was investigated as a potential treatment for progressive forms of multiple sclerosis (MS), but its development was stopped after negative results in a Phase 1/2 clinical trial.
Administered via an intravenous infusion directly into the bloodstream, the therapy was specifically tested in people with nonactive primary progressive MS (PPMS) and nonactive secondary progressive MS (SPMS).
ATA188 was developed by Atara Biotherapeutics based on growing evidence that the Epstein-Barr virus (EBV) plays a key role in triggering MS. In people with MS, immune B-cells infected with this virus are thought to contribute to inflammatory damage to the brain and spinal cord.
The therapy was made of immune T-cells obtained from healthy donors who had previously been infected with EBV. The goal was to eliminate EBV-infected B-cells in MS patients, which was expected to slow or even halt disease progression.
Therapy snapshot
| Treatment name: | ATA188 |
| Administration: | Intravenous infusion |
| Clinical testing: | Development stopped after negative results in a Phase 1/2 trial |
ATA188 in MS clinical trials
ATA188 was investigated in the Phase 1/2 EMBOLD trial (NCT03283826), which enrolled adults with nonactive PPMS and nonactive SPMS at sites in the U.S., Australia, and Canada.
- In EMBOLD’s Phase 1 part, a total of 24 participants received increasing ATA188 doses and were followed for one year to determine the optimal dose for further testing. Data from the trial and its long-term extension showed that 20 participants experienced sustained easing of disability or stable disability levels, and that several patients maintained these benefits for multiple years.
- The Phase 2 part then investigated the therapy in 103 EBV-positive patients who were randomly assigned to receive ATA188 or a placebo, followed by a crossover after one year. The goal was to assess whether ATA188 led to more patients experiencing a confirmed disability improvement (CDI) versus the placebo. The trial failed, however, with approximately 6% of ATA188-treated patients achieving CDI after one year compared with 16% in the placebo group.
Atara had announced plans to start two parallel Phase 3 trials to support regulatory applications of ATA188, but the negative results in the EMBOLD trial instead prompted the company to discontinue its development for MS.
ATA188 was well tolerated in MS clinical trials, with no safety concerns identified. Runny nose was the only treatment-related side effect reported in more than one person.
Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
FAQs about ATA188 in MS
ATA188 was an investigational therapy for multiple sclerosis (MS) whose development was stopped. The therapy was designed to kill immune B-cells infected with the Epstein-Barr virus (EBV), a leading risk factor of MS. This was expected to slow or even halt MS progression, but clinical findings failed to support that idea.
ATA188 failed to show significant benefits compared with a placebo in a Phase 2 clinical trial involving people with nonactive progressive forms of multiple sclerosis (MS). For that reason, its development was discontinued, and it’s very unlikely that the therapy will ever be approved by the U.S. Food and Drug Administration for MS.
Clinical trials of ATA188 excluded patients who were pregnant or breastfeeding, so it was not known if the treatment could be safely used during pregnancy. The development of ATA188 has since been discontinued.
Multiple sclerosis can manifest differently in each patient, so individual responses to treatment may vary. In a Phase 1 clinical trial of ATA188, disability improvements were evident in some patients as early as six months after starting treatment. However, no benefits were observed in the subsequent Phase 2 trial, leading to a discontinuation of the therapy’s development.
Neither hair loss nor weight gain was reported as an ATA188 side effect in multiple sclerosis clinical trials. In general, patients who experience these or other unexpected reactions to any medication should speak with their healthcare team.
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