Equillium (EQ) Stifel 2026 Virtual Immunology and Inflammation Forum summary

Program pipeline and scientific rationale

• EQ504 is an oral aryl hydrocarbon receptor (AhR) modulator formulated for colonic delivery, with an inhaled version in development for fibrotic and inflammatory lung diseases.

• EQ302 is an oral peptide inhibiting IL-15 and IL-21, targeting celiac disease and potentially other indications.

• EQ504 was selected for its improved solubility, potency, and selectivity over natural AhR modulators, addressing key drug development challenges.

• AhR plays a critical role in barrier tissues, modulating immune homeostasis and tissue integrity, with strong translational and clinical validation in ulcerative colitis and lung fibrosis.

• EQ504’s design enables local tissue delivery, optimizing target engagement while minimizing systemic exposure and potential side effects.

Preclinical and translational data

• EQ504 demonstrated efficacy in tissue healing models, improving epithelial barrier integrity and function in both cell lines and organoid systems.

• The molecule modulates immune responses by suppressing T effector cells and enhancing regulatory T cell activity, as well as shifting macrophages toward anti-inflammatory phenotypes.

• Preclinical studies confirmed EQ504 induces miR-124, a downstream biomarker of AhR activation, and modulates key cytokines like IL-10 and IL-22 in relevant models.

• CYP1A1 induction is used as a primary biomarker for AhR engagement, with translational work supporting its relevance across healthy and diseased tissues.

• Local delivery to the colon is expected to maximize efficacy in ulcerative colitis by targeting damaged epithelial and immune cells while reducing systemic exposure.

Clinical development and financial outlook

• Phase I study of EQ504 is set to begin in Q4, with first subject dosing triggering a $20 million financing tranche and data expected within six months.

• The phase I trial will focus on safety, tolerability, PK/PD, and proof of mechanism via CYP1A1 induction in colon biopsies from healthy volunteers.

• Inhaled EQ504 is advancing through formulation and toxicology studies, targeting indications such as COPD, IPF, and ILDs, with IND filing timing to be determined.

• EQ302 is positioned as an oral bispecific for celiac disease, aiming to address tissue distribution challenges seen with monoclonals and targeting a large patient population.

• Cash and equivalents stand at $57.2 million, with an additional $20 million expected, providing sufficient runway for ongoing and planned clinical activities.