Hybridon Unveils Oral Antisense Candidate For HIV

Hybridon already has an antisense drug targeting HIV infection called GEM 91 in clinical trials, but now believes it has gone one better with its second-generation candidates. Although only in early-stage development, animal studies suggest that these hybrid drugs may offer the possibility of delivering antisense therapy in tablet form.

The breakthrough has been reported in two studies published in the current issue of Biochemical Pharmacology. The results of the first study show that a hybrid oligonucleotide targeting the HIV gene gag has increased stability in vivo compared to a "standard" phosphorothioate oligonucleotide, which promises a longer duration of action and hopefully improved antiviral effectiveness.

The second study looked more closely at the feasibility of delivering the hybrid via the oral route. The drug was given to rats by mouth, and intact biologically-active drug was found in tissues (including plasma, kidney and liver), confirming that the compound is stable in the gastrointestinal tract and was absorbed.