Old drug may have new trick: Protecting against COVID-19 lung injury, study finds

Serendipity has attached to disulfiram almost from the start of its history as a medicine. The compound was originally used in the production of rubber, and was later investigated as an anti-parasite treatment. Incidental observations that people taking it became mildly sick whenever they drank alcohol led to its FDA approval in 1951 as a deterrent to alcohol consumption for people with alcohol use disorder.

Scientists found in 2020 that disulfiram also inhibits part of the inflammatory process that can lead to NET formation by white blood cells called neutrophils. The finding prompted the testing of disulfiram as a NET blocker. “NETs will damage the tissue, but since disulfiram interferes with gasdermin D, a molecule needed to produce NETs, no NETs are formed after disulfiram treatment,” Dr. Egeblad said.

After confirming in lab-dish experiments that disulfiram does greatly reduce the formation of NETs by human and mouse neutrophils, the researchers tested it in models of TRALI and COVID-19, two diseases that are known to feature extensive neutrophil invasion of the lungs, NET formation and often fatal lung damage.

In a mouse model of TRALI, disulfiram treatment a day before and then again three hours before induction of the syndrome allowed 95 percent of the animals to survive, compared to just 40 percent of those not treated with the drug. The findings showed that disulfiram, apparently by reducing NET formation, blocked the progressive damage to lung tissue and vessels that occurred in untreated mice, and in so doing allowed lung function to stabilize and recover relatively quickly after initial damage. By contrast, an inhaled drug called DNase 1, which has been investigated as a potential TRALI treatment, had no significant effect in improving the mouse survival rate even when administered minutes before TRALI induction.

In earlier collaborative work published in the Journal of Experimental Medicine, autopsy results suggested that NETs were present in severe COVID-19 patients and raised a novel possibility.

“Currently there aren’t any good treatment options for COVID-related lung injury, so disulfiram appears to be worth investigating further in this regard, particularly in severe COVID-19 patients,” Dr. Schwartz said.

Next the researchers tested disulfiram in a golden hamster model of COVID-19. This form of COVID-19 is less severe than what is seen in the worst human cases, but disulfiram treatment a day before or a day after infection with SARS-CoV-2 led to clearly favorable outcomes: less NET formation, less scar-like tissue formation (fibrosis) in the lungs, and gene activity changes suggesting a significant reduction in the harmful inflammatory response without impairment of antiviral immunity.

By comparison, the standard severe-COVID-19 treatment dexamethasone, an immune-suppressing steroid drug, did less to protect lung tissue from disease-related changes, and led to higher levels of SARS-CoV-2 in the lungs.

“Disulfiram’s strong inhibitory effect on NET formation and its improvement of disease outcomes in different rodent models highlight the potential for its use and for the future development of even better inhibitors of NET formation in a variety of diseases,” Dr. Schwartz said. Other researchers have begun small clinical trials of disulfiram in COVID-19 patients, although the results of those trials have not yet been published, he noted.

Story Source: Weill Cornell Medicine