A single dose of APL-10456, an adjuvanted recombinant protein subunit vaccine targeting rhinovirus, induced broad cross-reactive T cell responses against all three rhinovirus species in healthy adults, according to Phase I data reported by Apollo Therapeutics. The finding addresses a major obstacle that has frustrated rhinovirus vaccine development: the roughly 180 genetically distinct strains circulating across three species. Apollo noted that rhinovirus is responsible for an estimated 25%–50% of chronic obstructive pulmonary disease (COPD) exacerbations and over 600,000 COPD-related hospitalizations annually in the US.
APL-10456 addresses the dozens of distinct rhinovirus strains across three species by using a conserved protein antigen with high sequence homology across strains, combined with Th1-polarizing adjuvants designed to generate CD4+ and CD8+ T cell responses that recognize peptide sequences shared across all three species. Rather than relying on neutralizing antibodies alone, the strategy targets cellular immunity to accelerate viral clearance after infection regardless of which strain is encountered.
The Phase I randomized, double-blind, placebo-controlled study enrolled 144 participants across two parts. Part A evaluated three single dose levels in adults aged 18–54 years. Apollo reported that a single dose was well-tolerated, induced seroconversion, and generated Th1-skewed rhinovirus-specific cell-mediated immunity. T cell responses were detected against peptide pools representing RV-A, RV-B, and RV-C. The most common adverse events were mild-to-moderate injection-site reactions, and no serious adverse events were reported. No quantitative immunogenicity data — such as responder rates or fold-rise in titers — were disclosed. Part B, evaluating a two-dose regimen in adults aged 55 years and older, has completed enrollment and dosing, with results expected in Q4 2026. Apollo said it plans to initiate a randomized, double-blind, placebo-controlled Phase II trial in COPD patients in the first half of 2027.
Existing approved therapies for COPD — including bronchodilators, inhaled corticosteroids, and biologics such as Sanofi and Regeneron's Dupixent (dupilumab) and GSK's Nucala (mepolizumab) — address airway inflammation or selected COPD phenotypes but do not specifically target rhinovirus, while no rhinovirus vaccine or antiviral is approved. Apollo describes APL-10456 as the only vaccine in development for this indication, and the company said the Part A findings are consistent with preclinical data showing broad cross-strain immunity and rapid clearance of heterotypic rhinovirus.