Abstract
Oligonucleotide therapeutics are known to cause inflammatory adverse events such as influenza-like symptoms as a class effect. One of the possible mechanisms is the activation of the innate immune system via Toll-like receptors (TLRs), which are defense mechanisms against microbial nucleic acids. The challenges in evaluating the potential of innate immune activation are that the mechanism differs between humans and experimental animals, that it is difficult to predict clinical effects in the ordinal preclinical studies, and that test protocols for evaluation using human materials have not been fully established. To address these issues, a subgroup of the Consortium for Safety Evaluation of Oligonucleotide Therapeutics, in collaboration of five pharmaceutical companies, started a collaborative research project in FY2021 to establish an in vitro evaluation system that can detect innate immune activation potential in an early stage of drug development.
In the first year, we exposed human peripheral blood mononuclear cells (PBMC) to four TLR agonists (Poly(I:C) HMW, R848, ODN 2006, and ODN 2216) and confirmed a marked increase in the concentration of several cytokines in the culture supernatant and determined the conditions for positive control substances (presented at the 50th Annual Meeting). In the second year, we further evaluated the assay using antisense oligonucleotides (ASOs) with clinical data. The results showed similar cytokine changes for all ASOs, which were significantly lower compared to the positive controls (to be presented at this year's meeting). In the third and final year of the study, we are conducting a study to confirm the differences between studies and between institutions.
Through these studies, the extent of inter-donor differences and variation in cytokine measurements have been determined. The collaborative studies suggest that it is possible to evaluate the innate immune activating effects of oligonucleotide therapeutics by measuring cytokines using human PBMC.
