Shattuck Labs, Inc. (NASDAQ:STTK) saw its stock jump 17% on Monday after releasing Phase 1 clinical data for SL-325, its monoclonal antibody designed to block the DR3 receptor involved in inflammatory and immune-mediated conditions.
The early-stage study enrolled 72 healthy volunteers distributed across multiple dose cohorts spanning 0.1 mg/kg to 30.0 mg/kg. According to the company, SL-325 produced a low immunogenicity signal, with antidrug antibodies detected in 3.7% of participants.
Key pharmacodynamic findings included full DR3 receptor occupancy at every dose level tested, beginning at 0.1 mg/kg. At doses of 1 mg/kg and above, investigators observed complete blockade of TL1A binding to DR3 that persisted for more than three months. The report also notes that complete inhibition of TL1A binding was maintained for in excess of 10 weeks across dose groups.
Safety outcomes were favorable in this Phase 1 assessment. SL-325 was well tolerated across the studied dose range with no serious treatment-emergent adverse events reported. All treatment-related adverse events were Grade 1 in severity and occurred in 12 participants. The trial data showed no evidence of DR3 agonism or of SL-325 inducing lymphocyte proliferation.
Building on these results, Shattuck Labs intends to initiate RECEPTIVE-CD1, a randomized, double-blind, placebo-controlled Phase 2b trial in patients with moderate-to-severe Crohn's disease, in the third quarter of 2026. The trial will assess two dose levels of SL-325 administered as monotherapy versus placebo and is expected to enroll approximately 174 patients across sites in the United States, Canada, and Europe.
Separately, the company disclosed progress on its lead bispecific candidate, SL-846, which targets both DR3 and the IL-23 receptor. SL-846 is currently undergoing IND-enabling toxicology studies, and Shattuck expects to begin Phase 1 testing in the first half of 2027.
Implications for markets and sectors
- Biotechnology and pharmaceutical equities, particularly small-cap clinical-stage developers, are sensitive to trial readouts such as this and were directly affected by the share movement in STTK.
- Clinical-stage pipelines targeting immune-mediated diseases may receive renewed attention as companies and investors re-evaluate competitive positioning based on mechanism-specific data.
Further context and limitations
The information provided reflects the company's reported Phase 1 trial outcomes and its stated development timelines. The report does not include additional data beyond what was released regarding immunogenicity rates, duration of receptor blockade, safety grading, enrollment numbers, dosing ranges, or planned trial parameters.