Cabaletta Bio, Inc. SEC Filings

Cabaletta Bio filed an 8-K outlining its 2026 strategic priorities for rese-cel, its investigational CD19 CAR T therapy for autoimmune diseases. The company has initiated a dermatomyositis and antisynthetase myositis registrational cohort expected to evaluate 17 patients, targeting a Biologics License Application submission for rese-cel in myositis next year. Cabaletta has aligned with the FDA on new registrational cohort designs in systemic lupus erythematosus and lupus nephritis and received a Regenerative Medicine Advanced Therapy designation for systemic sclerosis, with further regulatory alignment updates planned in 1H26 and mid-2026. The company also obtained IND clearance to use Cellares’ automated Cell Shuttle platform for rese-cel manufacturing and expects multiple Phase 1/2 data readouts across RESET trials in 1H26.

Cabaletta Bio reported a larger quarterly loss as it advanced its cell therapy programs and flagged liquidity risk. For the three months ended September 30, 2025, net loss was $44.9 million, compared with $30.6 million a year ago, driven by higher research and development spending of $39.8 million versus $26.3 million. General and administrative expense was $6.8 million, roughly flat year over year.

Cash, cash equivalents and short‑term investments totaled $159.9 million as of September 30, 2025. The company disclosed that substantial doubt exists about its ability to continue as a going concern, noting current cash, cash equivalents and investments may not fund operations for at least the next twelve months from issuance of the financial statements.

To bolster liquidity, Cabaletta closed a June 2025 financing, raising net proceeds of $93.6 million through common stock, pre‑funded warrants and common stock warrants. As of quarter‑end, 6,000,000 pre‑funded warrants remained outstanding; no common warrants had been exercised. The company also established a $150.0 million at‑the‑market program in August 2025. Voting common shares outstanding were 96,265,204 as of October 31, 2025.

Cabaletta Bio, Inc. filed an 8-K announcing it released financial results for the third quarter ended September 30, 2025. The press release detailing these results was furnished as Exhibit 99.1.

The company stated that the information in Item 2.02, including Exhibit 99.1, is being furnished and is not deemed “filed” under Section 18 of the Exchange Act, nor incorporated by reference into Securities Act or Exchange Act filings except as specifically referenced. Cabaletta Bio’s common stock trades on the Nasdaq Global Select Market under the symbol CABA.

Cabaletta Bio reported an administrative update. The company filed an 8-K stating it posted an updated corporate presentation on October 29, 2025, available on the Investors & Media section of its website. The presentation is attached as Exhibit 99.1 and incorporated by reference. The filing is presented under Item 8.01 (Other Events) with related exhibits listed under Item 9.01(d).

Cabaletta Bio (CABA) furnished new rese‑cel clinical data and development updates across RESET‑Myositis, RESET‑SSc and RESET‑SLE, aligned to an ACR Convergence 2025 data cut as of September 11, 2025.

In RESET‑Myositis, all 4 DM/ASyS patients who met registrational criteria with sufficient follow‑up achieved immunomodulatory‑free TIS moderate or major improvement at week 16; safety included 4 of 13 with grade 1 CRS and no ICANS. The company will initiate a DM/ASyS registrational cohort enrolling 14 patients with a 16‑week primary endpoint, with enrollment starting this quarter. In IMNM, 2 of 4 with sufficient follow‑up achieved TIS at week 24 and additional Phase 1/2 enrollment is planned.

In RESET‑SSc, 4 of 4 patients with at least 3 months’ follow‑up achieved an rCRISS‑25 response off immunomodulators and steroids; low‑grade CRS occurred in three patients and one previously reported grade 3 ICANS event. In RESET‑SLE (n=9), three of four SLE patients achieved DORIS and renal responses were seen in lupus nephritis; all nine were off immunomodulators at cut‑off, with a median 8‑point SLEDAI‑2K reduction. A no‑preconditioning, weight‑based dose cohort will be added to RESET‑SLE, with initial data anticipated in 2026.

Cabaletta Bio (CABA) filed a Form 3 as an initial statement of beneficial ownership for its Chief Commercial Officer. The filing, effective as of 10/13/2025, states that no securities are beneficially owned. An Exhibit 24 Power of Attorney is included, and the document is signed by an attorney-in-fact.

This is a routine administrative disclosure noting the officer’s current ownership status at the time of joining or becoming subject to reporting.

Cabaletta Bio (CABA) disclosed a Form 4 showing its Chief Commercial Officer received a grant of stock options to purchase 275,000 shares at an exercise price of $2.49 on October 13, 2025.

The option was granted under the company’s 2025 Inducement Plan pursuant to NASDAQ Listing Rule 5635(c)(4). It vests with 25% on October 13, 2026, and the remainder in twelve substantially equal quarterly installments thereafter, subject to continued service. The option expires on October 12, 2035. Following the grant, the reporting person holds 275,000 derivative securities directly.

Cabaletta Bio reported early clinical and translational data for its autologous CAR T candidate rese-cel from three patients. All three showed substantial peripheral B cell depletion within the first month and rapid reductions in disease‑linked autoantibodies in two patients, consistent with deep tissue B cell depletion. Rese-cel had a generally tolerable safety profile: no ICANS was reported, one transient fever consistent with grade 1 cytokine release syndrome occurred, and one patient required a short steroid course for a post‑infusion flare but tapered below baseline by 3 months. Meaningful early clinical responses were seen by Pemphigus Disease Area Index (PDAI) scores: Patient 1 improved from 24 to 10 at 4 months, Patient 2 from 83 to 3 at 3 months, and Patient 3 from 22 to 2 at 1 month.

Cabaletta Bio, Inc. furnished an updated corporate presentation for investors under a Regulation FD disclosure. On September 3, 2025, the company posted this new “Corporate Presentation” to the “Investors & Media” section of its website and furnished it as Exhibit 99.1. The presentation is dated September 2025 and is provided as supplemental information only, as it is being furnished rather than filed and is not automatically incorporated into other Securities Act or Exchange Act filings unless specifically referenced.

Alyeska entities and Anand Parekh report shared beneficial ownership of 8,904,367 shares of Cabaletta Bio common stock, representing 9.9% of the outstanding class. The reported position reflects 4,800,000 directly held shares plus warrants exercisable only to the extent permitted under their terms so that post-exercise ownership does not exceed 9.9% of the company's outstanding common stock. The filing notes the warrant cap limits actual exercisable shares to 4,104,367 under the agreement and that the percentage calculation uses the issuer's prospectus share count of 89,943,101. The reporting parties filed a joint statement and certify the holdings are in the ordinary course of business.