2.2. Galidesivir (Immucillin-A, BCX4430)
Galidesivir is an adenosine nucleoside analog (Figure 3) that is an active site inhibitor of RdRp (EC50 < 50 µM). Similar to remdesivir, it is a prodrug that is metabolized by cellular kinases to the corresponding active form of nucleoside triphosphate. The triphosphate form binds to the active site of the viral enzyme and gets incorporated into the growing viral RNA chain resulting in premature chain termination. The drug is being developed by BioCryst, U.S., and being tested in a phase 1 clinical trial for COVID-19 or Yellow Fever in Brazil in collaboration with the U.S. NIAID (NCT03891420; n = 132) [44,45,46,47].
The drug is used parenterally and has demonstrated a broad-spectrum, showing in vitro antiviral activity against at least 20 RNA viruses across eight different virus families including coronaviruses. In animal studies, the drug was effective in protecting against dangerous viruses such as Zika, Yellow Fever, Marburg, and Ebola viruses [44,45,46,47].