SAB05 blocked CD40 signaling and delivered its glucocorticoid payload selectively into CD40-positive immune cells in vitro
In a mouse arthritis model, a surrogate of SAB05 at higher doses matched the efficacy of daily free glucocorticoid without the associated weight loss
Poster presentation November 9 at 10:30 a.m. ET
ALAMEDA, Calif., Nov. 9, 2026 (GLOBE NEWSWIRE) – Santa Ana Bio, a clinical-stage precision immunology company, today is presenting preclinical data on SAB05, its CD40-targeted glucocorticoid antibody-drug conjugate (ADC), at ACR Convergence 2026, the annual meeting of the American College of Rheumatology, in Orlando, Florida.
SAB05 delivers a highly potent glucocorticoid to CD40-expressing cells that drive autoimmune and inflammatory disease. The goal is to preserve the powerful effects of glucocorticoids while reducing their systemic exposure that can lead to toxicity.
“SAB05 combines two anti-inflammatory mechanisms in one molecule, blocking CD40 signaling and delivering a highly potent glucocorticoid into CD40-positive immune cells,” said Peter Emtage, Ph.D., founder and chief executive officer of Santa Ana Bio. “We believe the data presented today support developing SAB05 for immune-mediated diseases that respond to glucocorticoids.”
The poster (abstract #1047), “SAB05, a CD40-Targeted Antibody-Drug Conjugate of a Highly Potent Glucocorticoid, Delivers Cell-Selective Immunosuppression and Disease Control with Steroid-Sparing Safety in Models of Autoimmune and Inflammatory Disease,” will be presented from 10:30 a.m. to 12:30 p.m. ET in the Rheumatoid Arthritis – Translational Models and Mechanisms Poster B session.
Key findings:
- Cell-selective delivery. SAB05 was internalized and localized to the lysosome of CD40-positive cells. It activated the glucocorticoid receptor in CD40-positive but not CD40-negative reporter cells and induced the glucocorticoid-responsive genes GILZ and FKBP5 in CD40-positive B cells but not in CD40-negative T cells. By confining glucocorticoid activity to targeted cells, SAB05 has the potential to separate efficacy from steroid toxicity.
- Suppression of immune-cell activation. In human primary cells, SAB05 suppressed the activation of B cells, peripheral blood mononuclear cells, M1 macrophages, and monocyte-derived dendritic cells, and suppressed cytokine secretion in an allogeneic mixed lymphocyte reaction. This breadth across disease-driving cell types supports SAB05’s potential in multiple indications.
- T cell-dependent antibody responses. A single dose of the mouse surrogate nearly abolished the day 28 IgG response to the test antigen, keyhole limpet hemocyanin, with no effect on body weight, extending SAB05’s activity from cell assays to a durable effect in vivo after a single dose.
- Arthritis. In a therapeutic collagen-induced arthritis model, weekly dosing of the mouse surrogate at the two highest doses tested matched the efficacy of daily free glucocorticoid and outperformed the unconjugated antibody and an anti-TNF antibody. Mice in these groups ended the study above their starting body weight, whereas mice given daily free glucocorticoid lost weight, an in vivo signal of the steroid-sparing safety SAB05 is designed to provide.
About SAB05
SAB05 is an Fc-null, CD40-targeted antibody-drug conjugate that blocks CD40–CD40L signaling and delivers a low-permeability glucocorticoid payload, more potent than dexamethasone, into CD40-expressing immune cells. The molecule is designed to separate the efficacy of glucocorticoids from their systemic toxicity. SAB05 is in preclinical development.
About Santa Ana Bio
Santa Ana Bio is a biotechnology company developing a pipeline of innovative therapeutics that leverage a multi-omics platform to advance precision medicines for autoimmune and inflammatory diseases. The company’s mission is to improve the lives of patients affected by a wide range of chronic and life-impacting diseases. Santa Ana is advancing a portfolio of innovative product candidates designed to address the biology underlying autoimmune and inflammatory conditions. For more information, please visit www.santaana.bio and follow us on LinkedIn.
Contacts
Neil Abdollahian
[email protected]