Cabaletta Bio Says EULAR Data Bolster Rese-Cel Push Across Autoimmune Diseases

Cabaletta Bio (NASDAQ:CABA) executives said newly released EULAR data support the company’s strategy to advance its lead cell therapy candidate, rese-cel, across multiple autoimmune diseases, including myositis, scleroderma and lupus.

Speaking during a fireside chat, Chief Executive Officer Steven Nichtberger said Cabaletta has now treated more than 50 patients with rese-cel across “five or six different autoimmune diseases.” He said the company’s press release and updated corporate slide deck summarize findings being presented at EULAR on both efficacy and safety.

“We are thrilled to finally be able to share a body of data,” Nichtberger said, adding that Cabaletta views rese-cel as both “a pipeline and a product.”

Myositis Data Support Phase 3 Program

Nichtberger said that in Cabaletta’s Phase 1/2 myositis study, more than 80% of treated patients would have met the primary endpoint of the company’s ongoing Phase 3 program. He said current estimates suggest that “no more than 50%” of patients would need to be positive in that study to support a successful registrational filing.

The company is prioritizing dermatomyositis, an autoimmune condition for which Nichtberger said the current standard of care includes only one approved therapy, IVIG. He described IVIG as burdensome for patients and hospital systems and said rese-cel could offer a one-time approach that allows patients to stop other immunomodulatory medicines.

Nichtberger said 100% of patients who achieved the Phase 1/2 primary endpoint maintained their response throughout available follow-up, which extends as long as 1.5 years. He also said that 100% of patients treated with rese-cel in the myositis trial stopped myositis medicines and did not restart them, including those who did not meet the moderate or major Total Improvement Score threshold at week 16.

Cabaletta also reported treatment of the first patient with juvenile dermatomyositis. Nichtberger said the patient responded similarly to adults, with a moderate to higher-level Total Improvement Score response that has been durable. He said adult dermatomyositis and juvenile dermatomyositis are expected to form the basis of a biologics license application filing in the second half of 2027, and that the juvenile filing could create an opportunity for a priority review voucher.

Commercial Focus Includes Durability and Outpatient Use

Chief Commercial Officer Steve Gavel said Cabaletta is conducting market research with payers to determine what evidence will be required for reimbursement. He said payers have been consistent in wanting to see at least 52 weeks of durability, along with patients remaining off other therapies.

“What we’re starting to see in the data that we’re now obviously presenting here at EULAR … is we are starting to hit that mark,” Gavel said.

Gavel also highlighted rese-cel’s toxicity profile as a potential commercial advantage. He said the safety profile could allow most patients to be treated in outpatient settings, which he said is important because hospitals are resource constrained by inpatient cell therapy administration.

Gavel said 94% of patients do not experience cytokine release syndrome, or CRS. Nichtberger later clarified that two-thirds of all patients have no CRS and no ICANS, and that there has been no ICANS in the company’s myositis program. He described Grade 1 CRS as fever that has been manageable over a two- to three-day period.

Scleroderma Program Moving Toward Registrational Trial

Nichtberger said Cabaletta has aligned with the FDA on a registrational plan in scleroderma, where the company will focus on patients with interstitial lung disease. He said the primary endpoint in the single-arm study will be forced vital capacity, or FVC.

According to Nichtberger, about 70% of scleroderma patients develop interstitial lung disease, and current therapies are approved to slow decline rather than improve lung function. He said Cabaletta’s Phase 1/2 scleroderma data show improvements in interstitial lung disease measurements in the “vast majority” of treated patients and that 100% of patients achieved the revised ACR-CRISS endpoint by the end of one year.

On safety, Nichtberger said most scleroderma patients had modest side effects, with a majority having no CRS, some experiencing Grade 1 fever and one or two patients experiencing Grade 2 hypotension that resolved with intravenous fluids. He also discussed one Grade 3 ICANS case, which he attributed to a protocol violation related to screening for infection. He said Cabaletta has not seen another ICANS case in rese-cel patients in the 15 months since that event.

The company plans to initiate the scleroderma registrational trial in the coming months.

Preconditioning-Free Regimen Shows Early Signals

Cabaletta is also studying rese-cel without preconditioning chemotherapy. Nichtberger said that in pemphigus vulgaris, two of four patients treated at the lowest dose had durable outcomes at six months, and that one patient showed signs consistent with a durable immune reset.

In lupus, the company has dosed the first two patients with a preconditioning-free regimen. Nichtberger said one of the two showed pharmacokinetic and pharmacodynamic responses similar to patients who received rese-cel with preconditioning and later had an immune reset.

He said Cabaletta plans to escalate the dose in lupus and ultimately select a dose for a registrational program. However, he said the company does not expect to provide rapid updates on individual patients for competitive reasons.

Manufacturing Partnership Cited as Key to Scale

Nichtberger also pointed to Cabaletta’s partnership with Cellares as part of its strategy to support future demand. He said the company has already dosed “a couple of patients” with rese-cel produced by Cellares and presented data showing the product looked comparable to rese-cel produced elsewhere.

He said automated manufacturing could help Cabaletta achieve low cost of goods and avoid the capital investment historically associated with autologous CAR T manufacturing.

About Cabaletta Bio (NASDAQ:CABA)

Cabaletta Bio is a clinical-stage biotechnology company pioneering chimeric autoantibody receptor T cell (CAAR-T) therapies for B cell–mediated autoimmune diseases. Its proprietary platform engineers patient-derived T cells to selectively target and eliminate pathogenic B cells that produce disease-driving autoantibodies, with the aim of preserving overall immune function and reducing off-target toxicity.

The company’s lead candidate, DSG3-CAART, is being evaluated in pemphigus vulgaris, a rare blistering disorder caused by autoantibodies against desmoglein 3.