Cabaletta Bio (NASDAQ: CABA) to share new rese-cel RESET-PV data at ASGCT 2026

Rhea-AI Filing Summary

Cabaletta Bio filed a current report describing plans to present new clinical and translational data from four refractory pemphigus vulgaris patients treated with rese-cel in its RESET-PV trial. These patients received the lowest rese-cel dose without preconditioning chemotherapy and had 24–36 weeks of follow-up as of an April 2, 2026 data cut.

The company will share these data at the ASGCT 2026 Annual Meeting on May 14, 2026. Cabaletta also highlights broader development plans for rese-cel across several autoimmune diseases and notes it plans to add a new dose-escalation cohort to the RESET-SLE trial, with initial no-preconditioning dose data anticipated in the first half of 2026.

Insights

Biotech clinical-stage analyst

Cabaletta outlines upcoming rese-cel data in pemphigus vulgaris and broader autoimmune trials, but results and impact remain uncertain.

Cabaletta Bio plans to present early clinical and translational data from four refractory pemphigus vulgaris patients in the RESET-PV trial who received rese-cel at the lowest dose without cyclophosphamide or fludarabine preconditioning. Follow-up spans 24–36 weeks from an April 2, 2026 cutoff, so these are still initial observations.

The company links this dataset to a wider rese-cel program in SLE, myositis, systemic sclerosis, generalized myasthenia gravis, pemphigus vulgaris, and multiple sclerosis, including a new dose-escalation cohort in RESET-SLE with first no-preconditioning dose data expected in the first half of 2026. However, extensive risk language emphasizes uncertainties around safety, efficacy, enrollment, regulatory outcomes, and whether interim signals will predict longer-term results, underscoring that the ultimate clinical and commercial value is not yet clear.

8-K Event Classification

2 items: 8.01, 9.01

2 items

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Key Figures

Number of RESET-PV patients in dataset: 4 patients Follow-up duration range: 24–36 weeks Data cutoff date: April 2, 2026 +2 more

5 metrics

Number of RESET-PV patients in dataset 4 patients Refractory pemphigus vulgaris patients receiving lowest rese-cel dose without preconditioning

Follow-up duration range 24–36 weeks Follow-up for four RESET-PV patients as of April 2, 2026 data cutoff

Data cutoff date April 2, 2026 RESET-PV clinical and translational data used for upcoming presentation

ASGCT 2026 meeting date May 14, 2026 Planned presentation of new RESET-PV rese-cel data

Timing for initial RESET-SLE no-preconditioning data First half of 2026 Initial data at the first dose in no-preconditioning cohort

Key Terms

RESET-PV, rese-cel, preconditioning, Phase 1/2 clinical trials, +2 more

6 terms

RESET-PV medical

"The RESET-PV® (pemphigus vulgaris) trial at the American Society of Gene & Cell Therapy"

rese-cel medical

"patients that received rese-cel at the lowest dose without preconditioning in the RESET-PV trial"

preconditioning medical

"to evaluate rese-cel without the use of cyclophosphamide and fludarabine as preconditioning agents"

Preconditioning is a deliberate, controlled treatment or brief exposure to mild stress applied to cells, tissues, organs, or patients before a main medical procedure or therapy to make them more resistant to injury and improve the therapy’s effectiveness. For investors, evidence that a treatment benefits from preconditioning can signal higher chances of safer, more effective outcomes, smoother regulatory review, and a stronger commercial case—like a warm-up improving performance and reducing injury risk.

Phase 1/2 clinical trials medical

"advancement of separate Phase 1/2 clinical trials of rese-cel in patients with SLE, myositis, SSc, gMG and PV"

Orphan Drug Designation regulatory

"Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation and Fast Track Designation"

Orphan drug designation is a special status given to medicines developed to treat rare diseases affecting only a small number of people. This status often provides benefits like faster approval processes and financial incentives, making it more attractive for companies to develop these drugs. For investors, it signals potential for exclusive market rights and reduced competition, which can impact the drug’s profitability.

Fast Track Designation regulatory

"retain and recognize the intended incentives conferred by Orphan Drug Designation and Fast Track Designation or other designations"

A "fast track designation" is a process that speeds up the review and approval of a product or project, allowing it to reach the market or be completed more quickly than usual. For investors, it can signal that a product may become available sooner, potentially leading to earlier revenue or benefits, and indicating a priority status that might influence company performance and market opportunities.

Understanding 8-K Material Events →

false 0001759138 0001759138 2026-05-04 2026-05-04

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 4, 2026

CABALETTA BIO, INC.

(Exact name of Registrant as Specified in Its Charter)

Delaware		001-39103		82-1685768
(State or Other Jurisdiction of Incorporation)		(Commission File Number)		(IRS Employer Identification No.)

2929 Arch Street Suite 600
Philadelphia, Pennsylvania		19104
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s Telephone Number, Including Area Code: (267) 759-3100

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, par value $0.00001 per share		CABA		The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events.

Cabaletta intends to present new clinical and translational data from 4 refractory patients that received rese-cel at the lowest dose without preconditioning in the RESET-PV^® (pemphigus vulgaris) trial at the American Society of Gene & Cell Therapy (ASGCT) 2026 Annual Meeting, being held on May 14, 2026. The RESET-PV trial is the first study within Cabaletta’s RESET clinical development program to evaluate rese-cel without the use of cyclophosphamide and fludarabine as preconditioning agents.

Key clinical and translational insights from these 4 refractory patients who received rese-cel at the lowest dose without preconditioning and had follow-up between 24 and 36 weeks as of the data cut-off date of April 2, 2026, include:

• After discontinuing all immunomodulators, clear biologic and clinical activity was observed without preconditioning.

• 2 of 4 patients demonstrated compelling clinical activity through 6 months follow-up.

• 3 of 4 patients remained off all immunomodulators and steroids as of the data cut-off.

• Complete peripheral B cell elimination was observed in 3 of 4 patients.

• On safety, cytokine release syndrome (CRS) was observed in 1 of 4 patients (Grade 1) and no immune effector cell-associated neurotoxicity syndrome (ICANS) was observed of any grade.

• Based on the safety profile observed at the lowest dose, multiple additional patients have been enrolled at a higher dose cohort in the RESET-PV trial and durability data at the higher dose is anticipated in the second half of 2026.

• In the RESET-SLE trial evaluating rese-cel without preconditioning in patients with lupus, the initial dose cohort is fully enrolled with initial data at the first dose anticipated in the first half of 2026.

Forward-Looking Statements

The information under this Item 8.01 contains “forward-looking statements” of Cabaletta within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: Cabaletta’s business plans and objectives as a whole; Cabaletta’s ability to successfully complete research and further development and commercialization of its drug candidates in current or future indications, including the timing and results of Cabaletta’s clinical trials and its ability to conduct and complete clinical trials; expectation that clinical results will support rese-cel’s safety and activity profile; Cabaletta’s ability to leverage its emerging clinical data and its efficient development strategy; the clinical significance of the clinical data read-out at upcoming scientific meetings and timing thereof; the clinical significance of clinical and translational data from the RESET-PV trial evaluating rese-cel without preconditioning, including the anticipated timing and results of additional dose cohorts; the Company’s advancement of separate Phase 1/2 clinical trials of rese-cel in patients with SLE, myositis, SSc, gMG and PV and advancement of the RESET-MS trial, including updates related to status, safety data, efficiency of clinical trial design and timing of data read-outs or otherwise; and Cabaletta’s plans to incorporate a new dose-escalation cohort into the RESET-SLE trial and the status of enrollment in the initial dose cohort of the no preconditioning cohort in the RESET-SLE trial, with initial data at the first dose anticipated in the first half of 2026;

Any forward-looking statements in this Item 8.01 are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks related to regulatory filings and potential clearance; the risk that signs of biologic activity or persistence may not inform long-term results; Cabaletta’s ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; the risk that the results observed with the similarly-designed construct employed in academic publications, including due to the dosing regimen, are not indicative of the results we seek to achieve with rese-cel; risks that results from one program may not translate to results for another program; 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; risks related to clinical trial site activation, delays in enrollment generally or enrollment rates that are lower than expected; delays related to assessment of clinical trial results; risks related to unexpected safety or efficacy data observed during clinical studies; risks related to volatile market and economic conditions and public health crises; Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation and Fast Track Designation or other designations for its product candidates, as applicable; risks related to Cabaletta’s ability to protect and maintain its intellectual property position; risks related to fostering and maintaining successful relationships with Cabaletta’s collaboration and manufacturing partners; uncertainties related to the initiation and conduct of studies and other development requirements for its product candidates; the risk that any one or more of Cabaletta’s product candidates will not be successfully developed and/or commercialized; and the risk that the initial or interim results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Cabaletta’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in Cabaletta’s most recent annual report on Form 10-K as well as discussions of potential risks, uncertainties, and other important factors in Cabaletta’s other filings with the Securities and Exchange Commission. All information in this Item 8.01 is as of the date of this Current Report on Form 8-K, and the Company undertakes no duty to update this information unless required by law.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

104 Cover Page Interactive Data File (embedded within the Inline XBRL Document).

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

				CABALETTA BIO, INC.
Date: May 4, 2026				By:		/s/ Steven Nichtberger
						Steven Nichtberger
						Chief Executive Officer and President (Principal Executive Officer)

FAQ

What did Cabaletta Bio (CABA) announce in this 8-K filing?

Cabaletta Bio announced plans to present new clinical and translational data from four refractory pemphigus vulgaris patients treated with rese-cel in its RESET-PV trial at the ASGCT 2026 Annual Meeting, alongside an update on broader rese-cel development plans across multiple autoimmune indications.

What is the RESET-PV trial that Cabaletta Bio is highlighting?

RESET-PV is Cabaletta Bio’s clinical trial in pemphigus vulgaris evaluating rese-cel without cyclophosphamide or fludarabine preconditioning. The company will present data from four refractory patients treated at the lowest dose, each with 24–36 weeks of follow-up as of the April 2, 2026 data cutoff.

When and where will Cabaletta Bio present the new rese-cel data?

Cabaletta Bio plans to present the new RESET-PV clinical and translational data at the American Society of Gene & Cell Therapy (ASGCT) 2026 Annual Meeting, which is being held on May 14, 2026, providing an early look at rese-cel’s performance without preconditioning chemotherapy.

How many patients are included in Cabaletta Bio’s upcoming RESET-PV data readout?

The upcoming RESET-PV presentation will cover data from four refractory pemphigus vulgaris patients who received rese-cel at the lowest dose without preconditioning. These patients had between 24 and 36 weeks of follow-up as of the April 2, 2026 data cutoff referenced by the company.

What other rese-cel trials is Cabaletta Bio advancing besides RESET-PV?

Cabaletta Bio indicates it is advancing separate Phase 1/2 rese-cel trials in systemic lupus erythematosus, myositis, systemic sclerosis, generalized myasthenia gravis, and pemphigus vulgaris, plus the RESET-MS trial, reflecting a broad autoimmune pipeline anchored on the same cell therapy construct and development strategy.

What future milestone did Cabaletta Bio mention for the RESET-SLE trial?

Cabaletta Bio plans to incorporate a new dose-escalation cohort into the RESET-SLE trial’s no-preconditioning arm and notes that initial data at the first dose in this cohort are anticipated in the first half of 2026, marking an upcoming clinical milestone for its lupus program.

Filing Exhibits & Attachments

3 documents

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 3.1 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 17.6 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 11.0 KB