HIV Digest	HIV Digest Archive

Tipranavir was found to have activity against many forms of PI-resistant virus in a recent study comparing the efficacy and safety of tipranavir (TPV), a new HIV-1 protease inhibitor (PI), combined with low-dose ritonavir (RTV, Norvir) to other boosted PI regimens.

Patients who were failing a PI-containing regimen had a genotype performed. An expert panel reviewed the genotype and then suggested an optimized background regimen.

All 610 patients in the study were given resistance tests and assigned to an optimized background regimen of two drugs. Patients were randomized to add either tipranavir boosted with ritonavir (500 mg/200 mg) or a comparator PI (called a CPI) boosted with ritonavir, which could include one of the following PIs: lopinavir (LPV), amprenavir (APV, Agenerase), indinavir (IDV, Crixivan) or saquinavir (SQV, Fortovase, Invirase).

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By week 24, 263 of the patients in the tipranavir arm remained on treatment and 48 discontinued; only 13 patients experienced virologic failure. In comparison, only 151 in the CPI arm were still on treatment and 139 had discontinued with 109 people experiencing virologic failure.

However, toxicities such as nausea, diarrhea, and increased serum levels of ALT, cholesterol and triglycerides were seen significantly more frequently in the tipranavir arm of this study than in the CPI arm.

From these 24-week results, the authors concluded that tipranavir demonstrates significant efficacy and safety in treatment-experienced patients who have significant PI mutations. When boosted with ritonavir, tipranavir shows significantly more activity in terms of viral load reduction or CD4+ cell increase compared to other ritonavir-boosted regimens. The positive effect of tipranavir was clearly increased when drugs such as enfuvirtide were added to a regimen. Of concern was the significant amount of lipid abnormalities and gastrointestinal symptoms seen, which, although a consistent and expected finding with other ritonavir-boosted regimens, may limit tipranavir's use in some patients.

Editor's Note: from theBodyPro.com