Important Update on CAR-T Trials in Autoimmune Disease
MSU wants to update our community about important recent safety developments involving
CAR-T clinical trials for autoimmune diseases, including trials involving people with myositis.
Novartis – rap-cel (YTB323)
Novartis has temporarily paused screening, enrollment and treatment in its immunology and
neuroscience trials of rapcabtagene autoleucel (rap-cel/YTB323), a CD19-directed CAR-T
therapy, including its study in idiopathic inflammatory myopathies.
In information provided to the patient community, Novartis stated that the pause followed
notification of serious immune effector cell-associated hemophagocytic syndrome (IEC-HS)
events. The company is reviewing the clinical and safety data with independent Data Monitoring
and Steering Committees and is sharing information with global health authorities. Novartis has
indicated that it cannot provide additional details while the review is ongoing.
Separately, Novartis has confirmed to news organizations that three patients experienced serious
IEC-HS and that complications from these events resulted in fatal outcomes. Novartis is
conducting a comprehensive review to better understand what occurred and determine
appropriate next steps.
The company has stated that this is a temporary pause and not a discontinuation of the rap-cel
program. Patients who have already received treatment will continue to be monitored through
their clinical trial teams.
What is IEC-HS?
IEC-HS is a recognized but uncommon and potentially serious complication of CAR-T and other
immune-effector-cell therapies, previously observed primarily in patients receiving CAR-T for
blood cancers (e.g., myeloma).
It is a hyperinflammatory reaction in which activation of the immune system can become
excessive and affect multiple organs. It can be associated with high or rapidly rising ferritin,
abnormalities in blood counts and clotting, liver inflammation and, in severe cases, organ
dysfunction.
IEC-HS is related to, but distinct from, the better-known cytokine release syndrome (CRS) that
can occur following CAR-T treatment. IEC-HS can be treated, particularly when identified early,
but severe cases can be life-threatening. Each center has a protocol for treatment of adverse
effects.
At this time, we do not know why these serious events occurred in the Novartis autoimmune
program, and it would be premature to assume that the same risk applies to other CAR-T
products.
Bristol Myers Squibb – zola-cel
Bristol Myers Squibb (BMS) has separately voluntarily paused enrollment in autoimmune trials
involving its investigational CD19 CAR-T therapy, zolacabtagene autoleucel (zola-cel).
BMS has described the events prompting its decision as “transient and reversible
inflammatory events” identified during routine safety surveillance. The company is reviewing
its clinical data before determining next steps.
The circumstances therefore should not be assumed to be the same as those involving the
Novartis program.
Cabaletta – RESET-Myositis continues
Because many members of our community are following the RESET-Myositis trial, MSU
contacted Cabaletta Bio directly regarding the status of its investigational CD19 CAR-T therapy,
rese-cel.
Cabaletta confirmed to MSU that:
- RESET-Myositis continues to enroll patients.
- The FDA has not requested Cabaletta to pause enrollment in any rese-cel clinical trial.
- More than 90 patients with autoimmune diseases have now received a single, weight-based
- dose of rese-cel across the RESET program.
- According to Cabaletta, no cases of IEC-HS of any grade have been observed to date with res-cel.
Cabaletta also noted that rese-cel uses a well-characterized 9-day manufacturing process similar
to manufacturing approaches used for established oncology CAR-T products and the academic
CD19 CAR-T experience at Erlangen University.
RESET-Myositis continues to recruit participants, including patients with dermatomyositis
(DM).
What does this mean for patients?
These developments are important, but they should not be interpreted as evidence that all CAR-T
trials for autoimmune disease have the same safety concerns.
CAR-T therapies being studied by different companies are different investigational products.
They may differ in their CAR design, manufacturing process, dose, patient population and othercharacteristics. We do not yet know which factors contributed to the events now under investigation.
The experience also illustrates why clinical trials include intensive safety monitoring and
independent review committees. Pausing enrollment while unexpected safety findings are
investigated is an important part of that process.
CAR-T remains a promising but still investigational approach for myositis and other
autoimmune diseases and continued careful evaluation of both benefits and risks is essential.
MSU will continue communicating directly with companies and investigators involved in
myositis CAR-T research and will update our community as additional information becomes
Information current as of September 4, 2026
Please download the item below to read more about the CAR T therapy and share it with your family members.
This brochure was developed through a patient-centered process. Three people living with myositis who underwent CAR T cell therapy (two with dermatomyositis and one with antisynthetase syndrome) shared their experiences. Their insights shaped the content, ensuring that the questions and answers reflect the real concerns, challenges, and hopes of patients going through this journey.
To make sure the information is accurate and aligned with current research, the brochure was also reviewed by the Myositis Clinical Trial Consortium (MCTC), a leading group of specialists and researchers driving myositis clinical trials worldwide.
This combination of lived experience and expert review makes the brochure both authentic and reliable—a guide designed by patients, for patients, with the support of the medical community.
