One-time immune cell therapy held MS steady in early trial, maker says

Bristol Myers Squibb (BMS) has reported the first results of a one-time engineered immune cell treatment in 66 people with multiple sclerosis (MS) whose disease kept flaring or worsening despite standard drugs¹. The company said most patients treated at the main dose stayed stable without any other MS medicine during follow-up so far. It also disclosed that one patient died of pneumonia 44 days after treatment¹².

The therapy is called zolacabtagene autoleucel, or zola-cel (lab code BMS-986353)¹. The data were presented in a talk at MSToronto 2026, the 10th joint meeting of the American and European MS research societies, held October 21-23 in Toronto¹³.

What happened

Zola-cel is a CAR-T therapy. Doctors take a patient’s own T cells, a type of immune cell, and engineer them to carry a new receptor that locks onto a marker called CD19 on B cells, another kind of immune cell¹⁴. Before the infusion, patients get chemotherapy drugs (fludarabine and cyclophosphamide) that clear room in the immune system⁵.

The idea comes from blood cancers. Engineered T cells have been used to seek out and destroy cancerous B cells in lymphoma and leukemia. In MS, the thinking is that some B cells help drive the immune attack on the brain and spinal cord, so removing them deeply might “reset” the immune system⁴. BMS describes the aim as “treatment-free remission” after a single treatment¹.

The trial, called Breakfree-2, is a Phase 1 study, meaning an early test whose main goal is safety. It is single-arm, so every patient got the treatment and there was no comparison group¹⁵. It included 30 people with highly active relapsing MS (the type with flare-ups) and 36 with progressive MS (where disability builds steadily)¹. Patients had tried a median of two earlier MS drugs¹.

The evidence so far

BMS said that all 60 patients treated at the second dose level remained off their long-term MS drugs at last follow-up. Nine of them had been followed for more than 12 months¹. The company also said the treatment caused complete depletion of B cells¹.

The more detailed results come from a smaller group of 32 patients who got the second dose and had at least 26 weeks (about six months) of follow-up¹:

• Relapsing MS: 6 of 7 patients who could be assessed met a standard called “no evidence of disease activity”, meaning no relapses, no worsening disability and no new activity on MRI brain scans¹.
• Relapsing MS, disability: all 8 patients assessed on a common disability scale were stable or improved¹.
• Progressive MS: 22 of 24 patients (92%) were stable or improved on disability, even though their disease had been getting worse before treatment¹.
• Progressive MS, scans: all 24 showed no new MRI activity¹.

Jeffrey A. Cohen, a neurologist at the Cleveland Clinic quoted in the company’s release, said the data “suggest that CD19-directed CAR T cell therapy may offer a new approach to treating multiple sclerosis,” adding that “more research is needed”¹.

Safety and the death

Safety was the trial’s main goal¹. About 42% of patients (28 of 66) had cytokine release syndrome, a whole-body inflammatory reaction common with CAR-T. Most cases were the mildest grade, and all cleared in a median of two days¹.

Five patients (7.6%) had ICANS, a nerve-related side effect of this kind of therapy that can cause confusion and other symptoms. Most were mild to moderate and cleared in a median of two days. One severe (grade 4) case in a patient with progressive MS was treated with steroids and an anti-inflammatory drug and cleared within four days¹. At an earlier look at this trial in 2025, no ICANS had been reported⁴.

After the data cutoff, one patient with relapsing MS died. According to BMS, the patient developed late movement-related symptoms that the company said were not ICANS, and that did not improve with steroids and antibody infusions (IVIG). The patient was then given high-dose cyclophosphamide, developed septic pneumonia, and died the next day, 44 days after the infusion¹. BMS said the patient’s CAR-T cells had multiplied about as much as in other patients¹. Trade publication Scrip framed the challenge in its headline: BMS “must balance patient death with promise” of the therapy².

BMS said no other deaths from side effects have been reported across its zola-cel autoimmune programs, which have treated 190 patients in early studies¹.

What it does not show yet

These are interim results from an ongoing early trial, shared by the company that makes the treatment, and not yet published in a peer-reviewed journal. Several limits matter:

• No comparison group. Without patients on other treatments for comparison, it is not possible to say how much of the stability came from zola-cel¹.
• Small numbers. The detailed efficacy results rest on 32 patients, and some measures on only 7 or 8 people¹.
• Short follow-up. Only nine patients had more than a year of follow-up¹. MS often unfolds over many years, so whether any effect lasts is unknown.
• Risk. The treatment involves chemotherapy beforehand and side effects that need hospital-level care, and one patient died¹⁵.

The trial is still running. Its registry record lists an estimated 120 participants in total, including people with myasthenia gravis, a different autoimmune nerve-and-muscle disease, and a planned main completion date of July 15, 2027⁵.

Who is behind it

The study is sponsored by Juno Therapeutics, a Bristol Myers Squibb company, and started in March 2024⁵. The results above come from the company’s own announcement¹. Lynelle B. Hoch, who leads BMS’s cell therapy organization, said the company is advancing zola-cel “with the goal to redefine autoimmune care with a single, transformative treatment”¹.

Zola-cel uses the same engineered receptor as lisocabtagene maraleucel, a CAR-T therapy already approved for blood cancers. It is made with a newer process the company calls NEX-T, designed to shorten manufacturing time⁶.

How it fits the field

Zola-cel is one of several CAR-T therapies being tried in MS. A 2025 review counted six ongoing early trials and noted signs that these cells can reach the brain and spinal cord⁷. At the same Toronto meeting, another early study reported results for a different CAR-T product in 3 people with progressive MS⁴.

BMS is also testing zola-cel in other autoimmune diseases. In a 2025 report from an earlier trial, patients with systemic sclerosis, a disease that hardens skin and can scar the lungs, showed early improvements in skin and lung measures⁶. A larger trial comparing zola-cel with standard care in systemic sclerosis is registered, with 92 planned participants and a listed start date of February 2027⁸. Sources differ on that trial’s status: the official registry lists it as not yet recruiting⁸, while a drug-tracking database lists it as suspended, along with a mid-stage trial in two autoimmune blood disorders⁷. The sources reviewed do not explain the difference.

What to watch next

• Longer follow-up showing whether patients stay stable off MS drugs beyond one year.
• More detail on the patient who died, and whether the company changes how the trial is run.
• Whether BMS moves zola-cel in MS into a larger trial with a comparison group.
• Results from the myasthenia gravis part of the same study⁵.