A repurposed drug, originally abandoned as a cancer treatment, has demonstrated broad-spectrum antiviral activity in laboratory studies, potentially offering a single pill solution for common viral infections like the flu, common cold, norovirus, and even COVID-19. The drug, now known as MDL-001 (formerly ERA-923), works by targeting a conserved section of a viral enzyme critical for replication, a chokepoint in the viral lifecycle.
Repurposing a Forgotten Drug
The breakthrough came not through traditional drug development, but via an AI-powered platform developed by Model Medicines, a California-based company. This platform analyzed decades of chemical and biological data, identifying that ERA-923, which failed in clinical trials for breast cancer in the early 2000s, could inhibit a range of viruses through an unrelated mechanism. The AI identified that the drug could block the viral RNA-dependent RNA polymerase, a key enzyme used by many viruses to replicate their genetic material.
Lab Results: Wide-Ranging Activity
In lab tests, MDL-001 inhibited influenza A and B viruses, several coronaviruses (including those responsible for common colds and COVID-19), respiratory syncytial virus (RSV), norovirus, and hepatitis B, C, and D. Animal studies showed efficacy in mice infected with COVID-19 and hepatitis B/C, reducing viral loads and improving outcomes. This broad activity is significant because current antiviral treatments are typically virus-specific; a single drug that tackles multiple viral families is a novel approach.
Skepticism and Next Steps
While promising, the findings have met with some skepticism from experts. Peter White at the University of New South Wales notes that other drugs targeting the same viral enzyme have only worked against hepatitis C. Model Medicines argues that MDL-001 binds to the enzyme differently, allowing it to act across multiple viruses. Clinical trials are planned to begin early next year, first to establish safety, but the drug has previously shown minimal side effects in humans.
The potential impact of such a pill is substantial: rapid, at-home treatment for common viral illnesses would reduce lost productivity and offer a ready response to future pandemics. The idea of a single pill for viral infections is a major step forward.
“As far as we can tell, this is the first drug that’s ever demonstrated activity across all these viral families,” says Daniel Haders, co-founder of Model Medicines.
