Drug used for more than a decade to treat cancer could cure Covid-19

A drug that’s been used for more than a decade to treat cancer could cure people with Covid-19, according to a new study.

The drug, called pralatrexate, is a chemotherapy medication that was originally developed to treat lymphomas – tumours that originate in the glands.

Chinese researchers found pralatrexate outperforms remdesivir, which is currently the leading anti-viral medication used to treat Covid-19 patients. 

Pralatrexate was approved by the US Food and Drug Administration in 2009 for patients with terminal disease in spite of its toxicity. 

Adverse effects of pralatrexate include fatigue, nausea and mucositis – inflammation and ulceration of the mucous membranes lining the digestive tract. 

However, repurposing pralatrexate in a way that eliminates its side effects shows much potential, according to researchers.  

Colourised scanning electron micrograph of an apoptotic cell (pink) heavily infected with SARS-COV-2 virus particles (green), isolated from a patient sample. pralatrexate, a chemotherapy medication originally developed to treat lymphoma, could potentially be repurposed to treat Covid-19

‘Identifying effective drugs that can treat Covid-19 is important and urgent, especially the approved drugs that can be immediately tested in clinical trials,’ say the study authors, led by Dr Haiping Zhang at the Shenzhen Institutes of Advanced Technology, China. 

‘Our study discovered that pralatrexate is able to potently inhibit SARS-CoV-2 replication with a stronger inhibitory activity than remdesivir within the same experimental conditions.’   

Following the global outbreak of Covid-19, researchers were inspired by the idea of repurposing existing drugs that were originally developed to treat other conditions.  

Remdesivir was initially developed to treat hepatitis C and then repurposed as a potential Ebola treatment, Due to the similarity in the structures of these viruses to SARS-CoV-2, the virus which causes Covid-19, experts hoped it may be able to help fight the current pandemic 

Artificial intelligence can help identify such drugs by simulating how different drugs would interact with SARS-CoV-2, the virus that causes Covid-19. 

To aid virtual screening of existing drugs, Zhang and colleagues combined multiple computational techniques that simulate drug-virus interactions. 

They used this hybrid approach to screen 1,906 existing drugs for their potential ability to inhibit replication of SARS-CoV-2 by targeting a viral protein called RNA-dependent RNA polymerase (RdRP).

RdRP is an essential protein encoded in the genomes of all RNA-containing viruses, such as SARS-CoV-2.

The novel screening approach identified four promising drugs, which were then tested against SARS-CoV-2 in lab experiments. 

Two of the drugs, pralatrexate and azithromycin, successfully inhibited replication of the virus. 

Further lab experiments showed that pralatrexate more strongly inhibited viral replication than remdesivir, suggesting the former could potentially be repurposed for Covid. 

However, this chemotherapy drug can prompt significant side effects and, as it is used for people with terminal lymphoma, immediate use for Covid-19 patients is not guaranteed. 

Despite this, the findings support the use of the new screening strategy to identify drugs that could be tweaked, according to the team.

‘We have demonstrated the value of our novel hybrid approach that combines…