TMC278 is an investigational non-nucleoside reverse transcriptase inhibitor (NNRTI) under development by the Belgian company Tibotec.

Test-tube evidence suggests that TMC278 is effective against HIV that is resistant to other NNRTIs (de Bethune 2005). As it has a long half-life of 38 hours, it may be able to be dosed once a day.

In a seven-day trial of TMC278 alone in HIV-positive patients, median viral load dropped by 1.29 log₁₀ in patients taking 25mg daily, by 1.23 log₁₀ in those taking 50mg daily, by 1.07 log₁₀ in those taking 100mg daily and by 1.17 log₁₀ in thsoe taking 150mg daily (Goebel 2005). There was no change in the viral load of patients taking placebo. On the basis of these data, the investigators have not isolated a dose with which to move forward, although longer treatment may reveal a difference between these drug doses.

There were no serious side-effects in this study, and CD4 cell counts increased by a mean of 55 cells/mm³ in the patients taking TMC278.

A multinational phase IIb dose-finding study began in March 2005.

References

de Bethune MP et al. TMC278, a new potent NNRTI with an increased barrier to resistance and good pharmacokinetic profile. Twelfth Conference on Retroviruses and Opportunistic Infections, Boston, abstract 556, 2005.

Goebel F et al. TMC278: potent anti-HIV activity in antiretroviral therapy-naive patients. Twelfth Conference on Retroviruses and Opportunistic Infections, Boston, abstract 160, 2005.