As part of our Spotlight on Formulation series, Rob Harris, Director of Beyond Quality, has written a guest blog which discusses the drug repurposing exercise in the quest to find a vaccine and treatments for COVID-19.
The race is now on to develop a vaccine for COVID-19. In the meantime, our doctors are having to use whatever they have in their existing armoury to treat patients. Consequently, there’s been a second race to find the most effective drugs for treating the most severe COVID-19 symptoms. On the 14th September 2020, the market data and analysis company Global Data, stated that 1,239 drugs, including novel drug combinations, were currently in the pipeline globally. While 67.6% were in the discovery or pre-clinical phase, it could be argued that this has turned out to be the largest drug repurposing exercise ever known.
A few potential candidates soon made the headlines, some for the wrong reasons. The US pushed the use of hydroxychloroquine to ward off the virus, even though there was no evidence for its effectiveness as a prophylactic for COVID-19 and its use in this way being strongly opposed by medical opinion (it can lead to death in patients with underlying health issues). Of the 503 clinical trials testing the efficacy of hydroxychloroquine, 45 have been withdrawn, suspended or terminated (Global Data).
Gilead’s Remdesivir, which was developed to treat Ebola virus infection, but shown to be ineffective, is the new standard of care in the US and has Emergency Use Authorisation (EUA) in the US and in South Korea. Remdesivir is also approved in the EU, Japan, India, Singapore, Australia, and Canada for treatment in hospitalised patients. However, Remdesivir is not the game changer most were hoping for.
Much of the efforts in identifying drugs for treating COVID-19 patients have bordered on trial and error. However, there have been examples of multidisciplinary, collaborative and scientific thinking being practiced during these challenging times. For instance, an excellent paper was published in Nature in March 2020 which described the use of protein interaction mapping for SARS-CoV-2 to identify drugs which could potentially be used as anti-virals against COVID-19 (A SARS-CoV-2 protein interaction map reveals targets for drug repurposing. Nature, 583: 459–468). The work was conducted by a consortium of scientific groups from across the globe. It identified 69 compounds (29 drugs approved by the FDA, 12 in clinical trials and 28 pre-clinical compounds) which can interfere with SARS-CoV-2 and human protein interactions and hence potentially offer antiviral activity. As expected, there is now much activity in further evaluating antiviral activity of those compounds identified from the study.
Interestingly, hydroxychloroquine was amongst the 69 compounds mentioned above as having potential antiviral activity. Did the US know something we didn’t? For the rest of us, we watch with anticipation at the outcomes of the Herculean repurposing effort occurring on a global scale.