Clinical trials of niclosamide for COVID-19
Based on promising preclinical data, niclosamide is currently being evaluated as a potential COVID-19 treatment in 18 clinical trials relying on different formulations and/or routes of administration. Details of these trials can be found on public registries such as ClinicalTrials.gov and the WHO’s Trial search website. Twelve of these trials are in Phase 2/3 and investigate the efficacy of niclosamide across the full COVID-19 disease spectrum (Figure 2 and Table 2).
In the pre-symptomatic and mild COVID-19 disease stage, the potent antiviral activity of niclosamide is thought to limit disease symptomatology and progression. However, as COVID-19 progresses towards moderate and severe disease, the bronchodilatory and anti-inflammatory effects of niclosamide might contribute to efficacy. Its antibacterial efficacy could also benefit COVID-19 patients at risk for secondary bacterial infections, which is one of the leading causes of mortality in COVID-19 (Cevik, Kuppalli, Kindrachuk, & Peiris, 2020), particularly since the introduction of immunomodulators such as dexamethasone and tocilizumab as standard of care (SoC) medications.