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regarding our current beliefs, expectations and assumptions regarding: our business, future plans and strategies for our CAAR T technology; our ability to grow our autoimmune-focused pipeline; the ability to capitalize on and potential benefits
resulting from our research and translational insights; including those related to any similarly-designed constructs or dosing regimens; the anticipated market opportunities for rese-cel in patients with autoimmune diseases; the Company s
business plans and objectives; our expectations around the potential success and therapeutic and clinical benefits of rese-cel and our other product candidates, as well as our ability to successfully complete research and further development and
commercialization of our drug candidates in current or future indications, including the timing and results of our clinical trials and our ability to conduct and complete clinical trials; expectation that clinical results will support
rese-cel s safety and activity profile; our plan to leverage increasing clinical data and a unique development program for rese-cel; the clinical significance of the clinical data read-out at upcoming
medical or scientific meetings; our belief that rese-cel may enable achieving drug-free, durable meaningful clinical responses, through an immune reset; the Company s advancement of separate Phase 1/2 clinical trials of rese-cel in patients
with SLE, myositis, SSc and gMG and advancement of the RESET-PV and RESET-MS trials, including updates related to status, safety data, efficiency of clinical trial
design and timing of data read-outs or otherwise; our ability to leverage our experience in autoimmune cell therapy; our ability to enroll the requisite number of patients, dose each dosing cohort in the intended manner, and advance the trial as
planned in our Phase 1/2 clinical trials of rese-cel; the timing any planned regulatory filings for our development programs, including IND applications; the progress and results of our MusCAARTe Phase 1 trial, and impact around reported safety and
clinical and translational data of cohorts from our MusCAARTe Phase 1 trial; Cabaletta s advancement of the whole blood manufacturing program as a potential replacement for apheresis, as well as its potential alignment with FDA in connection
thereto; expectation that clinical results will support rese-cel s safety and activity profile; statements regarding the timing of regulatory filings and interactions with regulatory authorities, including such authorities review of
safety information from our ongoing clinical trials and potential registrational pathway for rese-cel; our ability to successfully complete our preclinical and clinical studies for our product candidates, including our ability to enroll the
requisite number of patients, dose each dosing cohort in the intended manner, and progress the trial; our ability to increase enrollment from our rapidly expanding clinical network in the RESET clinical trial program in the US and Europe; our
ability to obtain and maintain regulatory approval of our product candidates, including our expectations regarding the intended incentives conferred by and ability to retain Fast Track Designations for our product candidates; our ability to
accelerate our pipeline and to develop meaningful therapies for patients, including in collaboration with academic and industry partners and the ability to optimize such collaborations on our development programs; our ability to contract with
third-party suppliers and manufacturers and retain such manufacturers, whether due to legislative action or otherwise; to implement an enhanced manufacturing process and further develop our internal manufacturing strategy, capabilities and
facilities; our ability to execute our manufacturing strategy to enable expansion of clinical supply and efficiently scale commercial supply for rese-cel; our potential commercial opportunities, including value and addressable market, for our
product candidates. Words such as, but not limited to, look forward to, believe, expect, anticipate, estimate, intend, plan, would, should
and could, and similar expressions or words, identify forward-looking statements. Various risks, uncertainties and assumptions could cause actual results to differ materially from those anticipated or implied in our forward-looking
statements. Such risks and uncertainties include, but are not limited to, risks related to the success, cost, and timing of our product candidate development activities and preclinical studies and clinical trials, risks related to our ability to
demonstrate sufficient evidence of safety, efficacy and tolerability in our preclinical studies and clinical trials of rese-cel and MuSK-CAART, the risk that the results observed with the similarly-designed construct, including, but not limited to,
due to dosing regimen, are not indicative of the results we seek to achieve with rese-cel, the risk that signs of biologic activity or persistence may not inform long-term results, the risk that persistence observed with effective CD19-CAR T oncology studies in combination with lymphodepletion is not indicative of, or applicable to, clinical responses in patients with mPV, risks related to clinical trial site activation or enrollment rates
that are lower than expected, our ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; risks that modifications to trial design or approach may not have the
intended benefits and that the trial design may need to be further modified; our ability to protect and maintain our intellectual property position, risks related to our relationships with third parties, uncertainties related to regulatory
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to regulatory filings and potential clearance, the risk that any one or more of our product candidates will not be successfully developed and commercialized, the risk that the results of preclinical studies or clinical studies will not be predictive
of future results in connection with future studies, and risks related to volatile market and economic conditions and public health crises. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and
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Develop and launch the first curative targeted cellular therapies for patients with autoimmune diseases
3 2025: Realizing our vision by defining an efficient path to approval Planning to leverage increasing clinical data and unique
development program for rese-cel (resecabtagene autoleucel; CABA-201) Compelling clinical efficacy Unique development strategy Multiple near-term catalysts with favorable safety profile designed to accelerate
time including clarity on potential & rapidly growing enrollment to approval and launch path to approval Compelling clinical efficacy data in Multiple disease-specific cohorts with a Plan to meet with FDA to align on
active, refractory autoimmune patients1 common design allow for a potentially registrational trial design in 1H25 Favorable safety profile in first 10 accelerated path to approval with broad Enroll and complete dosing in multiple
patients dosed, 90% experienced either evaluation of autoimmune indications disease-specific cohorts in 2025 no CRS or grade 1 (fever) CRS and One weight-based dose administered as Present clinical data on rese-cel at 90% experienced
no ICANS a single infusion; dose supported by medical meetings throughout 2025, clinical & translational data1 Immunosuppressant-free outcomes including data evaluating rese-celobserved with patients discontinuing all
Industry-leading clinical network without preconditioning immunosuppressants from rese-cel with 44 active clinical sites and growing in infusion through follow up period1 the US and Europe2 Patients are seeking a drug-free, symptom-free life which
is rarely achieved despite current therapies; physicians also prioritize prevention of end-organ damage3 1. Abstract 1733: Safety and efficacy of CABA-201, a fully
human, autologous 4-1BB anti-CD19 CAR T cell therapy in patients with immune-mediated necrotizing myopathy and systemic lupus erythematosus from the RESET-MyositisTM and RESET-SLETM clinical trials. ACR
Convergence 2024. 2. Clinicaltrials.gov as of December 31, 2024 4 3. Golder, et al. Lupus. 2018;27(3): 501-506
Innovative clinical strategy with potential for accelerated regulatory path RESET clinical program has disease-specific cohorts designed
to evolve directly into registrational studies Program1 Trial Preclinical Phase 1/2 Pivotal Dermatomyositis Rheumatology Antisynthetase syndrome RESET-Myosit Neurology Immune-mediated necrotizing myopathy Dermatology Juvenile Myositis Contains
cohort(s) without preconditioning Pediatric Indication Lupus Nephritis RESET-SLE Rese-cel FTD Non-Renal SLE (CABA-201) Skin +
Organ Cohort RESET-SSc 4-1BB CD19-CAR T Skin Cohort AChR-Ab pos. gMG RESET-MG AChR-Ab neg. gMG
RESET-MS Relapsing MS Progressive MS RESET-PV Mucocutaneous & mucosal pemphigus vulgaris RESET REstoring SElf-Tolerance; Ab Antibody; AChR
Acetylcholine receptor; gMG Generalized myasthenia gravis; MS Multiple sclerosis; SLE Systemic lupus erythematosus 1. Additional pipeline candidate includes MuSK-CAART for MuSK-Ab positive MG, currently being evaluated in a
Phase 1 trial. 2. FDA Fast Track Designation received in dermatomyositis, SLE and lupus nephritis, systemic sclerosis, mucosal pemphigus vulgaris, MuSK-Ab positive MG, and multiple sclerosis. 5
Chimeric Antigen Receptor T Cells for Autoimmunity (rese-cel) 6
Rese-cel: CD19-CAR T specifically designed for autoimmunity Cabaletta rese-cel binder with
similar in vitro & in vivo activity to construct used in academic studies1,3 Rese-cel product design & clinical / translational data Fully human anti-CD19 binder 4-1BB costimulatory domain
with fully human binder Binder with similar affinity & biologic activity to academic FMC63 binder while binding to the same epitopes1,2 4-1BB costimulatory domain Same weight-based dose as in
academic studies Potential to provide immune reset based on CD3- signaling domain initial clinical and translational data5 Rese-cel4 Initial patients treated with rese-cel have shown
compelling clinical responses with safety data that supports autoimmune development6 1. Peng, Binghao J, et al. Preclinical specificity and activity of CABA-201, a fully human 4-1BB containing CD19 CAR T therapy for treatment-resistant autoimmune disease. Poster presented at: American Society Gene and Cell Therapy 26th Annual Meeting; 2023 May 19; Los Angeles, CA. 2. Dai, Zhenyu, et
al. Development and functional characterization of novel fully human anti-CD19 chimeric antigen receptors for T-cell therapy. Journal of Cellular Physiology
236.8 (2021): 5832-5847. 3. M ller, Fabian, et al. CD19 CAR T-Cell Therapy in Autoimmune Disease A Case Series with Follow-up. New England Journal
of Medicine 390.8 (2024): 687-700. 4. Transmembrane domain in rese-cel is CD8 vs. TNFRSF19 (Troy) utilized in the academic construct. The two transmembrane domains have not been shown to have a
significant difference in function or IFN- ³ production in preclinical studies. The CD8 transmembrane domain is employed in tisagenlecleucel. 5. Volkov, Jenell, et al. Case
study of CD19 CAR T therapy in a subject with immune-mediate necrotizing myopathy treated in the RESET-Myositis phase I/II trial. Molecular Therapy 32.11 (2024): 3821-3828. 6. Abstract 1733: Safety and Efficacy of CABA-201, a Fully Human, Autologous 4-1BB Anti-CD19 CAR T Cell Therapy in Patients with Immune-Mediated Necrotizing Myopathy and Systemic Lupus 7 Erythematosus from the
RESET-MyositisTM and RESET-SLETM Clinical Trials. ACR 2024.
RESET program addressing several autoimmune markets Broad por ith six RESET trials designed to address high unmet need and realize the
potential of rese-cel Phase 1/2 TrialsNo Flu/Cy Myositis SLE SSc gMG MS PV Typical onset middle age Affects young women & Middle age onset Bimodal age of onset Chronic inflammation, Pure autoantibody &Only FDA-approved people of color common axon loss, cognitive B-cell mediated therapy is IVIg in DM Progressive skin & Profound weakness that impairment, and ~40% with
lupus can be disabling autoimmune disease High mortality due to nephritis, which carries organ fibrosis with lung, irreversible neurologic Risk for myasthenic Characterized by painful lung & cardiac ~25% risk of death or cardiac, renal
damage damage crises, with respiratory blisters & erosions involvement ESRD within 10y Average survival of 12y failure U.S. Prevalence ~68k ~160-320k ~88k ~55k ~750k ~13k EU Prevalence ~85k ~150k ~60k
~100k ~550k ~21k Rheum Neuro Derm SLE Systemic lupus erythematosus; DM Dermatomyositis; SSc Systemic sclerosis; gMG Generalized myasthenia gravis; MS multiple sclerosis; 8 ESRD
End-stage renal disease; PV pemphigus vulgaris
Industry-leading clinical site footprint across RESE program1 +1 SLE site in Europe SLE sites Myositis sites Juvenile myositis sites SSc
sites MG sites PV sites 21 patients enrolled2 across the RESETTM studies, with 44 actively recruiting clinical sites in the US & Europe 1. Data per clinicaltrials.gov as of December 31, 2024, as compared to companies with actively
recruiting U.S. clinical sites for autoimmune cell therapy trials under company-sponsored INDs. 2. As of December 31, 2024. 9
Rese-cel Clinical & Translational Data (Based on Presentation at ACR Convergence 2024) 10
Key inclusion and exclusion criteria in RESETTM clinical program Designed to evaluate the safety and tolerability of rese-cel in
subjects with active, refractory disease Key inclusion criteria1 3 Evidence of active disease despite prior or current treatment with standard of care RESET-Myosit RESET-SLE RESET-SSc Age 18
and 65 with an SLE diagnosis Age 18 and 75 with a diagnosis of IIM Positive ANA or anti-dsDNA at screening (ASyS, DM, or IMNM) Age 18 and 70 with a limited or diffuse SLE (non-renal): active, moderate to severe SSc diagnosis Presence of at least one myositis antibody SLE, SLEDAI-2K 8; pure class V LN patients Evidence of
significant skin, pulmonary, JIIM: Age 6 and 17 with presence of at least eligible for this cohort renal, or cardiac involvement one MSA or MAA LN: active, biopsy-proven LN class III or IV ( class V) Key exclusion
criteria1 3 B cell-depleting agent within prior 3-6 months; Previous CAR T therapy and/or HSCT Presence of kidney disease other than LN Cancer-associated myositis Current symptoms of
severe, progressive, or Severe lung or cardiac impairment Significant lung or cardiac impairment uncontrolled pulmonary or cardiac disease Anticipate enrolling and completing dosing in multiple disease-specific cohorts in 2025;
similarly designed RESET-MG Phase 1/2 trial enrolling ASyS, antisynthetase syndrome; CAR, chimeric antigen receptor; DM, dermatomyositis; HSCT, hematopoietic stem cell trans on; IIM, idiopathic inflammatory
myopathy; JIIM, juvenile idiopathic inflammatory myopathy; LN, lupus nephritis; MAA, myositis-associated antibody; SLEDAI-2k, SLE disease activity index 2000; SSc, systemic sclerosis. 1. ClinicalTrials.gov.
Available at: www.clinicaltrials.gov/study/NCT06121297 (accessed October 2024). 2. ClinicalTrials.gov. Available at: www.clinicaltrials.gov/study/NCT06328777 (accessed October 2024). 11 3. ClinicalTrials.gov. Available at:
www.clinicaltrials.gov/study/NCT06154252 (accessed October 2024).
Baseline characteristics of first 8 patients in the RESE program All patients had active, refractory disease and most had failed B
cell-targeting therapi RESET-Myositi RESET-SLE RESET-SSc SLE-1 SSc-Skin-1 Patient /
Cohort IMNM-1 IMNM-2 DM-1 SLE-2 SLE-3 LN-1 Class V LN (severe skin cohort) Age, sex 33 M 60 M 57 M 26 M 36 F 44 F 24 F 66 F Disease duration ~2 years ~4 years ~4 years ~6 years ~17 years ~9 years ~2 years ~2 years Autoantibodies SRP HMGCR SAE dsDNA
dsDNA dsDNA dsDNA RNA P III MMT-8 SLEDAI-2K mRSS Baseline 130 126 131 26 10 8 22 42 Disease activity* CK (U/L) UPCR (mg/mg) 617 4725 94 1.08 n/a n/a 7.22 Therapies
at GC, ANI, VOC, GC, MTX GC, IVIG GC, MMF, HCQ GC, MMF, HCQ GC, AZA, HCQ HCQ, MMF, BEL MMF Screening MMF, HCQ Other prior CYC, BEL, VOC, MSC, RTX, ANI, RTX, IVIG RTX, MMF, MTX IVIG GC, MTX BEL, LEF HCQ therapies TAC BEL, ADA, MTX GC dose at 5 5 20
10 7 n/a 20 n/a Screening (mg/day) *Baseline disease activity = activity before pre-conditioning. SLE-1 had class V LN; inclusion criteria for LN cohort
requires class III/IV LN. ADA, adalimumab; ANI, anifrolumab; AZA, azathioprine; BEL, belimumab; CK, creatinine kinase; dsDNA, double-stranded DNA; GC, glucocorticoid; HCQ, hydroxychloroquine; HMGCR, 3-hydroxy-3-methylglutaryl-coenzyme A reductase; IVIG, intravenous immunoglobulin; LEF, leflunomide; MMF, mycophenolate mofetil;
MMT-8, manual muscle testing 8; mRSS, modified Rodnan skin score; MSC, mesenchymal stem cell; MTX, methotrexate; RNA P III, RNA polymerase III; RTX, rituximab; SAE, small ubiquitin-like modifier activating