Tapeworm drugs hold promise to cure Covid

A group of medications long prescribed to treat tapeworm has inspired a compound that shows two-pronged effectiveness against Covid-19 in laboratory studies, a new study suggests.

The study, published in the journal ACS Infectious Disease, indicates that the compound, part of a class of molecules called salicylanilides, was designed in the laboratory by a team of researchers, including Kim Janda from Scripps Research. "It has been known for 10 or 15 years that salicylanilides work against certain viruses. However, they tend to be gut-restricted and can have toxicity issues," Janda said.

The experiments showed that of the many modified salicylanilides he had built in his laboratory, No 11 affected pandemic coronavirus infections in two ways. First, it interfered with how the virus deposited its genetic material into infected cells, a process called endocytosis which requires the virus to form a lipid-based packet around viral genes.

The packet enters the infected cell and dissolves, so the infected cell's protein-building machinery can read it and churn out new viral copies. No 11 appears to prevent the packet's dissolution. "The compound's antiviral mechanism is the key," Janda said. "It blocks the viral material from getting out of the endosome, and it just gets degraded. This process does not allow new viral particles to be made as readily," the researcher added. Importantly, because it acts inside cells rather than on viral spikes, questions about whether it would work in new variants like Delta and Lambda aren't a concern, he adds.

"This mechanism is not dependent on the virus spike protein, so these new variants coming up aren't going to relegate us to finding new molecules as is the case with vaccines or antibodies," Janda said.