Desperate Times, Desperate Measures: The Case for RRx-001 in the Treatment of COVID-19

Semin Oncol. 2020 Oct;47(5):305-308. doi: 10.1053/j.seminoncol.2020.07.002. Epub 2020 Jul 7.


This article summarizes the likely attenuation properties of RRx-001 in COVID-19 based on its mechanism of action and the putative pathogenesis of the disease, which appears to activate inflammatory, oxidative, and immune cascades with the potential to culminate in acute respiratory distress syndrome, cytokine storm and death. An ongoing pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 appears to present with 3 major patterns of clinical symptomatology: (1) mild upper respiratory tract infection, (2) non-life-threatening pneumonia, and (3) severe pneumonia and acute respiratory distress syndrome that initially manifest as a mild prodrome lasting for 7-8 days before rapid clinical and radiological deterioration requiring ICU transfer. RRx-001 is a targeted nitric oxide donor. This small molecule, which has been evaluated in multiple Phase 1-2 clinical trials for cancer as well as a Phase 3 clinical trial for the treatment of small cell lung cancer called REPLATINUM (NCT03699956), is minimally toxic and demonstrates clear evidence of antitumor activity. During the course of these clinical trials it was noted that the rate of chronic obstructive pulmonary disease exacerbation and pneumonia in actively smoking small cell lung cancer patients treated with RRx-001 is less than 1%. Due to extensive history of tobacco use, 40%-70% of patients with lung cancer have chronic obstructive pulmonary disease and the expected rate of pulmonary infection in this population is 50%-70%, which was not observed in RRx-001 clinical trials. Moreover, in preclinical studies of pulmonary hypertension, RRx-001 was found to be comparable with or more effective than the FDA approved agent, Bosentan. The potential pulmonary protective effects of RRx-001 in patients with recurrent lung infections coupled with preclinical models demonstrating RRx-001-mediated reversal of pulmonary hypertension suggests RRx-001 may have therapeutic activity in patients with acute respiratory symptoms due to COVID 19. Clinical trials have been initiated to confirm the hypothesis that RRx-001 may be repurposed to treat SARS-CoV-2 infection.

Keywords: COVID-19; Nitric oxide; RRx-001; SARS-CoV-2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antihypertensive Agents / therapeutic use
  • Azetidines / therapeutic use*
  • Bosentan / therapeutic use
  • COVID-19 / epidemiology
  • COVID-19 / virology
  • COVID-19 Drug Treatment*
  • Drug Repositioning / methods
  • Drug Repositioning / trends
  • Humans
  • Lung / drug effects
  • Lung / physiopathology
  • Lung / virology
  • Nitric Oxide Donors / therapeutic use
  • Nitro Compounds / therapeutic use*
  • Pandemics
  • SARS-CoV-2 / drug effects*
  • SARS-CoV-2 / physiology


  • Antihypertensive Agents
  • Azetidines
  • Nitric Oxide Donors
  • Nitro Compounds
  • RRx-001
  • Bosentan