Potent Anti-Inflammatory: OP-101


Current anti-inflammatory drugs cause broad immune suppression leading to side effects and secondary infections


  • Targets the cause of hyperinflammation at its source, including activated macrophages attacking lungs and organs

  • Restores the number of macrophages to normal levels, preventing further inflammation from occurring

  • Profound effects of reducing neuroinflammation in multiple animal models

  • Converts activated proinflammatory macrophages and microglia to normal anti-inflammatory phenotype, preventing further inflammation from occurring

OP-101: A Targeted Selective Anti-Inflammatory Agent

Dexamethasone does appear to be life saving for those sickest patients …but it's a pretty big sledgehammer in terms of what it does to the immune system. Maybe there's something a little more subtle that would be even more effective with less in the way of side-effects.

Merad & Martin Nature Rev 2020

Mechanism of Action

  • OP-101 (acetylcysteine zidrimer) is selectively taken up by activated macrophages – More potent than steroids across multiple models
  • Mechanism demonstrated in animal models of lipopolysaccharide (LPS) induced inflammation (ARDS, TB, neuroinflammation, etc.)
  • After uptake, OP-101 returns macrophage to “normal” shutting down multiple pathways resulting in inflammation.
  • OP-101 also reduces oxidative stress, a process that can damage cells (corticosteroids do not address oxidative stress)

Kannan 2012; Nance 2017

OP-101: Safety Established in Healthy Humans

2x Phase 1, Single-dose – Intravenous Doses Up to 40 mg/kg

Subcutaneous Doses Up to 8 mg/kg
Excellent Safety Profile to Date
5-10x Therapeutic Window – Predicted Therapeutic Dose = 2-8 mg/kg

Study Objectives:

Complete safety, Pharmacokinetics (PK) metabolism, clearance and safety of single-dose administration in adult subjects

Study Results Summary:

  • All doses well tolerated with no clinical adverse events
  • No metabolites detected in urine
  • Complete recovery of the drug in the urine in healthy humans (no cellular uptake)

Excellent Safety Profile to Date

5-10x Therapeutic Window – Predicted Therapeutic Dose = 2-8 mg/kg

Phase 2a Trial in Severe COVID-19 Patients

Double Blind, Placebo Controlled Study of OP-101 in Severe COVID-19 Patients

OP-101 Dosed at 2, 4 or 8 mg/kg IV

Top-line Study Results

  • OP-101 improved survival compared to standard of care placebo control (82.4% vs 42.8%)
  • Significant and sustained reduction in pro-inflammatory biomarkers above corticosteroids alone (p < 0.01)
  • Significantly reduced neuronal injury biomarker (p < 0.001) to healthy control levels
  • Well tolerated with no drug related adverse events
  • Shuts down multiple pathways associated with hyperinflammation and crosses the blood-brain barrier

Study Published: Gusdon et al., Sci. Transl. Med. 14, eabo2652 (2022) 20 July 2022