Amantadine variant - aryl conjugates that inhibit multiple M2 mutant - amantadine resistant influenza a viruses

Abstract

Influenza A viruses can cause a serious future threat due to frequent mutations. Amantadine and rimantadine inhibit influenza A M2 wild-type (WT) viruses by binding and blocking M2 WT channel-mediated proton current. The resistant to the drugs amantadine and rimantadine influenza A viruses bearing the S31 N mutant in the M2 proton channel can be inhibited by amantadine - aryl conjugates, in which amantadine and an aryl group are linked through a methylene, which block M2 S31 N channel-mediated proton current. However, the M2 amantadine/rimantadine resistant viruses bearing one of the four mutations L26F, V27A, A30T, G34E in residues that line the M2 protein pore pose an additional concern for public health. Here, we designed 33 compounds based on the structure of three previously published and potent amantadine-aryl conjugates against M2 S31 N virus, by replacing amantadine with 16 amantadine variants. The compounds were tested against M2 WT and the five M2 amantadine-resistant viruses aiming at identifying inhibitors against multiple M2 mutant - amantadine resistant viruses. We identified 16 compounds that inhibited in vitro two influenza A viruses with M2 WT or L26F channels. Additionally, compounds 21 or 32 or 33, which are conjugates of the rimantadine variant with CMe2 (instead of CHMe in rimantadine) or the diamantylamine or the 4-(1-adamantyl)benzenamine with the 2-hydroxy-4-methoxyphenyl aryl group, were in vitro inhibitors against three influenza A viruses with M2 WT or L26F or S31 N, while compound 21 inhibited also in vitro the M2 G34E virus and 32 inhibited also in vitro the M2 A30T virus. For these compounds we performed a preliminary drug metabolism and pharmacokinetics study. Also, using electrophysiology, we showed that compound 21 was an efficient blocker of the M2 WT and M2 L26F channels, compound 32 blocked efficiently the M2 WT channel and compound 33 blocked the M2 WT, L26F and V27A channels. The drug metabolism and pharmacokinetics studies showed these compounds need further optimization.