PHILADELPHIA, PA — Cabaletta Bio Inc. (Nasdaq: CABA) reported sustained clinical responses lasting at least one year in small groups of patients with three severe autoimmune diseases following a single infusion of its experimental cell therapy, strengthening the clinical evidence behind a treatment the Philadelphia biotechnology company plans to submit for regulatory approval in 2028.
The Phase 1/2 findings, presented at the American College of Rheumatology’s Convergence 2026 meeting in Orlando, Florida, showed that patients with dermatomyositis, lupus nephritis and systemic sclerosis experienced improvements in disease activity while remaining off immunomodulatory medications.
Cabaletta’s investigational therapy, resecabtagene autoleucel, or rese-cel, is being developed to reset immune system activity in patients with autoimmune diseases that can cause organ damage, disability and death.
The findings came from open-label, single-arm clinical studies in which patients received one weight-based infusion of rese-cel following preconditioning treatment. The data cutoff was Sept. 4, 2026.
The company reported that all six dermatomyositis patients evaluated at one year maintained moderate-to-major responses on the Total Improvement Score, a measure of disease improvement, without immunomodulatory medications.
Five of those six patients, or 83%, had achieved that response by Week 16, the assessment point corresponding to the primary endpoint in Cabaletta’s ongoing registrational study involving dermatomyositis and antisynthetase syndrome.
Most patients were also no longer taking steroids at Week 52.
Improvements extended to muscle strength, skin disease activity and patient-reported physical function and fatigue.
The results are significant for Cabaletta’s development program because the company expects to report topline findings from its registrational adult dermatomyositis and antisynthetase syndrome cohort during the second half of 2027.
Cabaletta plans to submit a Biologics License Application to the Food and Drug Administration in the first quarter of 2028 for rese-cel in myositis, incorporating adult dermatomyositis findings and available juvenile dermatomyositis Phase 1/2 data.
Separate results involving lupus nephritis, an autoimmune condition that damages the kidneys, showed remission and favorable biopsy findings among five patients who underwent repeat kidney tissue examinations.
All five met the Definition of Remission in Systemic Lupus Erythematosus, or DORIS, while taking no immunomodulators and either no steroids or low-dose steroids.
Repeat kidney biopsies also showed histologic response or remission in all five patients, indicating reduced or absent disease activity in the examined tissue.
The biopsies were optional, making the findings specific to the patients who underwent the additional procedure.
Cabaletta indicated that the results could help distinguish persistent proteinuria caused by earlier structural kidney damage from proteinuria associated with ongoing disease activity.
That distinction matters because some patients may continue showing elevated protein levels in urine despite improvements in kidney tissue, potentially preventing them from meeting conventional criteria for complete renal response.
In systemic sclerosis, a disease associated with skin thickening and potentially serious internal organ complications, five of seven patients achieved an rCRISS-50 response after one year.
The measure evaluates improvement across multiple aspects of systemic sclerosis disease activity.
Six of the seven patients, or 86%, achieved the less stringent rCRISS-25 response.
Among five patients with interstitial lung disease, average percent-predicted forced vital capacity improved by 9% after one year.
Forced vital capacity measures the amount of air a person can forcibly exhale and is used to assess lung function.
Patients also demonstrated improvement in skin involvement, measured using the modified Rodnan Skin Score.
Cabaletta is enrolling a registrational systemic sclerosis cohort focused on patients with interstitial lung disease, a serious complication associated with the condition.
The company also presented safety findings from 71 patients treated with rese-cel following preconditioning across clinical studies involving myositis, systemic sclerosis, lupus and myasthenia gravis.
Of those patients, 67, or 94%, experienced either no cytokine release syndrome or Grade 1 symptoms, the mildest classification.
Four patients, representing 6%, experienced Grade 2 cytokine release syndrome.
Cytokine release syndrome is an inflammatory reaction associated with certain immune-based therapies.
The company reported that 68 of 71 patients, or 96%, experienced no immune effector cell-associated neurotoxicity syndrome, a neurological complication associated with cell therapies.
No cases of immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome, another potentially serious inflammatory complication, were reported.
David J. Chang, MD, Cabaletta’s chief medical officer, emphasized the duration of responses and patients’ ability to discontinue medications used to suppress or modify immune activity.
“In three different autoimmune diseases where patients are at risk of severe disability, end-organ damage, and increased risk of death despite current therapies, a single weight-based dose of rese-cel delivered immunomodulator-free clinical improvements that were durable through at least one year with a favorable benefit-risk profile,” Chang stated.
The results remain preliminary because they involve small patient groups treated in studies without randomized comparison arms.
The one-year dermatomyositis findings involve six patients, while the lupus nephritis biopsy results involve five and the systemic sclerosis analysis includes seven.
The data therefore provide early evidence of clinical activity and durability rather than establishing how rese-cel compares with existing treatments.
Cabaletta presented the dermatomyositis findings in an oral presentation Nov. 8 and the lupus nephritis results in a poster presentation Nov. 9.
The company also hosted an industry-supported symposium Nov. 10 examining the therapy and its broader RESET clinical development program.
Cabaletta is developing rese-cel as a targeted cell therapy intended to produce lasting improvements in autoimmune disease activity following a single treatment.
Its next major development milestones include the anticipated 2027 registrational results in dermatomyositis and antisynthetase syndrome and the planned 2028 regulatory submission for myositis.
Support the local news that supports Chester County. MyChesCo delivers reliable, fact-based reporting and essential community resources—free for everyone. If you value that, click here to become a patron today.