Considerations for the Characterization and Interpretation of Results Related to Alternative Complement Activation in

Scott P Henry1, Rosanne Seguin2, Joy Cavagnaro3

  • 11 Preclinical Development, Ionis Pharmaceuticals, Inc. , Carlsbad, California.

Insights

Phosphorothioate oligonucleotides can activate the alternative complement pathway, particularly in monkeys. This review details the mechanism, investigation strategies, and implications for clinical relevance.

Area of Science:

  • Pharmacology
  • Immunology
  • Toxicology

Background:

  • Phosphorothioate oligonucleotides are known to induce immune responses.
  • Complement activation is a significant concern in oligonucleotide safety studies.
  • The alternative complement pathway is frequently implicated.

Purpose of the Study:

  • To summarize discussions on oligonucleotide-induced complement activation.
  • To outline best practices for characterizing this effect.
  • To clarify clinical relevance and species specificity.

Main Methods:

  • Review of subcommittee discussions.
  • Analysis of toxicology study data.
  • Examination of chemical modification impacts.

Main Results:

  • Alternative complement pathway activation is common in monkeys with single-stranded phosphorothioate oligonucleotides.
  • Species specificity is a key consideration.
  • Chemical modifications can influence activation.

Conclusions:

  • Characterizing complement activation requires a strategic approach.
  • Understanding species differences is crucial for interpreting results.
  • Clinical relevance assessment is essential for oligonucleotide safety.