Replies to post #48144 on Biotech Values

[DewDiligence]

Re: Tyzeka vs Clevudine

>small modifications can markedly alter the therapeutic and toxicity patterns of various chemotherapeutics. Just taking a gander at the structures says little about how similar these two agents are.<

True as a generalization, but the generalization does not hold in this case. We know that:

1. Both molecules are direct antiviral agents with high specificity against HBV. (E.g., neither agent has activity against HIV.)

2. Both molecules are polymerase inhibitors that inhibit HBV replication by acting as chain terminators in the HBV polymerase.

3. Both molecules accomplish polymerase chain termination by mimicking the naturally occurring thymidine nucleoside. (Tyzeka is the biologically inactive stereoisomer of naturally occurring thymidine.)

4. Last but not least, the two molecules have generated roughly similar clinical results to date in the single-agent treatment of chronic HBV infection.

All told, I would say, yes, these molecules are very similar.