PARIS - The Belgian company Tibotec Group NV reported "highly potent" activity for two of its leading anti-HIV compounds, TMC 120, a non-nucleoside reverse transcriptase inhibitor (NNRTI), and TMC 126, a protease inhibitor.

A multicenter Phase II trial of TMC 120, in which patients received 100 mg of the drug twice a day for a week, resulted in a decrease of up to 2 log (100 times) in viral load and a mean decrease of 1.51 ± 0.22 log (33-fold) at the end of the treatment. All patients responded to the therapy, which proved safe and well tolerated.

Tibotec, of Mechelen, also unveiled the results of in vitro studies showing that TMC 120 is equally effective against wild-type HIV-1 and NNRTI-resistant strains with K103N, Y181C and G190A/S mutations. The compound proved active against a high proportion of NNRTI-resistant recombinant clinical isolates as well.

TMC 126, which is the series prototype in Tibotec's research program on new protease inhibitors, "demonstrates an extraordinary capability to block viral replication in vitro across a broad spectrum of multidrug-resistant HIV strains while retaining high potency," the company said. It added that its PIs also show a "strong capacity for suppressing the emergence of resistant virus strains in laboratory experiments."

Tibotec said that TMC 126 is the only protease inhibitor to exhibit both these characteristics, the combination of which is known as "resistance repellence." - James Etheridge