Human antibody for acute infection treatment of RSV

The National Institute of Allergy and Infectious Diseases awarded Trellis Bioscience, Inc. $999,759 on August 1, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to complete clinical trial preparation of TRL3D3, a human monoclonal antibody targeting respiratory syncytial virus.

TRL3D3 is directed against the RSV G protein, which serves as the key attachment factor for infecting airway epithelial cells and modulates host immune response contributing to pathological airway congestion. The award funds fill/finish manufacturing and bioanalytical characterization to advance TRL3D3 as a leading clinical candidate for acute RSV infection treatment. Existing approved prophylaxis monoclonal antibodies (palivizumab and nirsevimab) and numerous agents targeting the viral F protein have not yielded drugs for acute infection treatment, and escape from anti-F protein agents has been documented; preclinical research demonstrates TRL3D3 is highly effective as an acute infection therapeutic in model systems.

Work is performed in California. The period of performance extends from August 1, 2026, through July 31, 2028. This is a Project Grant, the standard assistance type under the program for supporting innovative research addressing infectious disease threats.

Abstract

Respiratory syncytial virus (RSV) is a leading cause of serious lower respiratory tract disease. The monoclonal antibody (MAB) palivizumab (synagis®) is only approved for prophylaxis against RSV in premature birth infants. Nirsevimab (beyfortus®) has recently been approved to prevent RSV in full-term infants. Neither of these mabs, or numerous other agents tested over the past two decades targeting the same viral protein (the F protein), has yielded a drug approved for acute infection treatment. Moreover, escape from anti-F protein agents has been well documented. Preclinical research has established that the other major RSV envelope protein (the G protein) is the key attachment factor for infecting airway epithelial cells. The same protein, both as viral associated and as a soluble factor secreted from infected cells, modulates the host immune response in a manner that contributes substantially to the pathological airway congestion. Trellis's human MAB TRL3D3 against the G protein is highly effective as an acute infection therapeutic in model systems. IT is the leading clinical candidate for validating the G protein as a therapeutic target in humans. In this CRP proposal, we will complete the preparation of TRL3D3 for clinical trials (fill/finish and bioanalytical characterization).