Molnupiravir

Molnupiravir is an orally effective experimental antiviral drug developed to treat the influenza flu.

It is a prodrug of the synthetic nucleoside derivative N4hydroxycitidine and by introducing copy errors during viral RNA replication it exerts its antiviral effect.

Highlights

The drug was developed at Emory University by the university’s pharmaceutical innovation company, Drug Innovation Ventures at Emory (DRIVE). Ridgeback Biotherapeutics, acquired it and later they worked with Merck & Co. to develop the drug further. Thor’s hammer, Mjölnir was the inspiration of this drug’s name. The idea is that the drug takes down the virus, like a powerful blow from the god of thunder.

Molnupiravir is metabolized to a cytidine-like ribonucleoside analog, βDN 4-hydroxycytidine 5′-triphosphate. During replication, the EIDD1931-5` virus triphosphate RNA polymerase enzyme accumulates in the newly produced RNA instead of using actual cytidine.

Molnupiravir can switch between two forms, one mimics uridine (U) and the other mimics cytidine (C). When the viral polymerase RNA tries to copy the molnupiravir, it sometimes interprets it as U and sometimes as a C. This leads to a massive number of mutations in all subsequent virus copies that exceed the threshold for the virus survive.

The active metabolite of molnupiravir, EIDD1931, was also found to induce DNA mutations  in a mammalian cell culture test, raising concerns about its possible carcinogenic and teratogenic effects. The first synthesis of molnupiravir was disclosed in a patent which was filed in the year by Emory University.