UPDATE: Cabaletta Bio (CABA) - The Third Gate Just Cracked Open
EULAR drops 83% DM responders at 1.5-year durability, SSc named as second pivotal indication, the first JDM patient hits — and the stock yawns at $3.58.
Executive Summary: The Data I Was Waiting For at EULAR Landed Better Than I Expected
On May 14, after the ASGCT no-preconditioning readout, I wrote that EULAR was “the big week” and that “the PC-free Lupus signal is the commercial market-expander.” I framed three gating questions in the original deep dive: can you scale manufacturing cheaply, can you give it without chemo, and will the FDA bless the single-arm myositis design.
The first two got real, positive data points across the spring. Today’s EULAR drop attacks the third one — not by getting a yes from the agency, but by widening the BLA bet so it doesn’t depend on one trial design in one indication anymore.
Cabaletta announced systemic sclerosis (SSc) as a second pivotal indication, with a ~25-patient single-arm registrational study in SSc-ILD starting 4Q26 using an FVC-based primary endpoint at 52 weeks. They also dropped the strongest myositis durability data I’ve seen from this program — 83% (5/6) of adult DM patients achieved an IM-free moderate-to-major TIS response at 16 weeks, with all five maintaining response off all immunomodulators through latest follow-up as long as 1.5 years. And the first juvenile dermatomyositis (JDM) patient hit a moderate TIS response maintained to 32 weeks, putting JDM into the 2H27 BLA submission alongside adult DM and opening the door to a priority review voucher via Rare Pediatric Disease Designation.
The stock closed at $3.58, down 0.8% from May 14’s $3.61. That is a market that is not paying attention.
