Electra Therapeutics Launches Phase 1 Trial of ELA822, a SIRPγ-Specific Antibody for Chronic T Cell-Mediated Diseases
核心洞察
Electra Therapeutics (搜索) has initiated a Phase 1 trial of ELA822 (搜索), a fully human SIRPγ (搜索)-specific monoclonal antibody, in healthy volunteers, with the study beginning in Europe in August 2026.
ELA822 (搜索) is designed to selectively deplete activated pathogenic T cells while sparing naive and regulatory T cells, potentially enabling durable use in chronic immune and inflammatory diseases.
Preclinical data in giant cell arteritis (搜索) and graft-versus-host disease (搜索) models showed reduced activated T cell infiltration and inflammatory cytokine expression, with improved disease activity and survival measures.
Electra Therapeutics (搜索) has initiated a Phase 1 clinical trial of ELA822 (搜索), a novel SIRPγ (搜索)-specific monoclonal antibody, in healthy volunteers, the South San Francisco-based clinical-stage biopharmaceutical company announced on Sept. 10, 2026. The study, a randomized, placebo-controlled, single-ascending-dose trial, will evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of ELA822. According to a separate regulatory filing, the Phase 1 healthy volunteer study began in Europe in August 2026.
ELA822 (搜索) is a fully human IgG1κ monoclonal antibody designed to selectively bind SIRPγ (搜索), with no binding to SIRPα (搜索) or SIRPβ1. Signal regulatory proteins (SIRP) are a family of cell surface receptors whose expression is restricted to specific immune cell populations and increases upon activation, enabling selective depletion of disease-driving cells while preserving normal immune function. SIRPγ is expressed predominantly on T cells, and by engaging cells expressing high levels of SIRPγ, ELA822 is designed to deplete activated, pathogenic T cells while sparing naive and regulatory T cells.
Preclinical Activity in T Cell-Driven Disease Models
In nonclinical models of giant cell arteritis (搜索) and graft-versus-host disease (搜索), ELA822 (搜索) reduced activated T cell infiltration and inflammatory cytokine expression and was associated with improvements in measures of disease activity and survival. The antibody was also well-tolerated in non-human primate studies, according to the company.
"We have built significant expertise at Electra in the biology of SIRP protein expression across activated immune cell populations and applying that biology to precision immune cell depletion," said Graham Parry, Ph.D., Chief Scientific Officer of Electra Therapeutics (搜索). "Selective targeting of individual SIRP members has historically been challenging, and because SIRPγ (搜索) is expressed only in primates, preclinical characterization of SIRPγ-targeted therapies has been limited."
Parry said the company's discovery platform has produced antibodies with well-defined and differentiated binding characteristics, ranging from pan-SIRP engagement, as with lead clinical candidate ipsoprubart (搜索), to highly specific SIRPγ (搜索) targeting, as with ELA822 (搜索). "We have also built humanized model systems to evaluate SIRPγ engagement. In those, ELA822 demonstrated selective depletion of activated T cells in vitro and activity in humanized mouse models of T cell-driven diseases in vivo," he said.
Positioning in Chronic T Cell-Mediated Disease
"ELA822 (搜索) is the second development candidate from our proprietary library of SIRP-targeted antibodies to advance into the clinic, extending our precision immune cell depletion approach to address unmet needs in chronic immune and inflammatory diseases," said Kim-Hien Dao, D.O., Ph.D., Chief Medical Officer of Electra Therapeutics (搜索). "Many approaches to T cell-driven diseases broadly suppress or deplete immune cells, which can limit their use in chronic settings. By selectively targeting SIRPγ (搜索) to deplete activated pathogenic T cells, we believe ELA822 may be well suited for a broad range of chronic T cell-mediated diseases where durable efficacy and long-term tolerability are important therapeutic objectives."
Pipeline Context and Financing Plans
ELA822 (搜索) is the second clinical-stage product candidate generated from Electra's proprietary library of SIRP-targeted antibodies. The company's lead product candidate, ipsoprubart (搜索) (ELA026), is a pan-SIRP monoclonal antibody currently in a global registrational program for secondary hemophagocytic lymphohistiocytosis (搜索) (sHLH), a severe hyperinflammatory syndrome for which there are no broadly approved therapies and survival has remained consistently poor over the past two decades. Ipsoprubart is also being evaluated in a clinical trial for T cell and natural killer cell malignancies.
According to a regulatory filing dated Aug. 28, 2026, Electra plans to list on the Nasdaq Global Select Market under the ticker "ETRA." Proceeds from the proposed offering are intended to fund registrational trials for ipsoprubart (搜索) in sHLH, oncology expansion, and early clinical development of ELA822 (搜索), including advancing the candidate through the Phase 1 healthy volunteer study and starting a Phase 1/2 trial in T cell-mediated disorders.
The filing describes ipsoprubart (搜索) as being in a global Phase 2/3 registrational study in sHLH and holding FDA Breakthrough Therapy and Fast Track designations as well as EMA PRIME designation. It also reports that a Phase 1b trial of ipsoprubart showed 100% 8-week overall survival and 100% overall response rate in 12 frontline monogenic HLH patients, with 8 of 8 objective tumor responses in sHLH patients with T/B-cell lymphomas. Electra reported a net loss of $62.0 million for fiscal year 2025 and had 46 employees as of June 30, 2026, with approximately 30 clinical sites planned globally for the SURPASS study.