Rese-cel's registrational myositis readout will test whether Phase 1/2 response rates hold in a confirmatory single-arm cohort supporting BLA submission

Bull

A positive outcome would be a high proportion of the ~17-patient registrational cohort achieving a moderate or major TIS response at 16 weeks after discontinuation of all immunomodulators, consistent with the 80% rate seen in Phase 1/2. This would validate the Phase 1/2 signal as reproducible, support BLA submission, and establish rese-cel as a potentially curative, immunomodulator-free therapy in DM and antisynthetase syndrome — indications with no approved disease-modifying options — substantially de-risking the entire platform.

Bear

The most likely failure modes are a meaningful drop in response rate in the registrational cohort due to patient selection differences, difficulty in achieving or maintaining immunomodulator discontinuation in a broader population, or delayed or incomplete responses that do not meet the 16-week primary endpoint. Any response rate materially below the Phase 1/2 benchmark would raise questions about whether the earlier data was inflated by small-sample variability or favorable patient selection, undermining the BLA pathway and the broader platform thesis.