Kaletra is an HIV protease inhibitor approved for the treatment of HIV-1 infection. It consists of two components: lopinavir and ritonavir. Lopinavir is an inhibitor of the HIV protease, which is a chemical necessary for HIV to multiply. Ritonavir inhibits the (CYP3A-mediated) metabolism of lopinavir, thereby increasing levels of lopinavir in the blood. The FDA has granted accelerated approval to Kaletra based on favorable results in reducing HIV viral load and on CD4 T-cell counts.
Patients Who Have Not Received Prior Antiretroviral Therapy
Study 863 is an ongoing, randomized, double-blind, multicenter trial comparing treatment with Kaletra versus nelfinavir. Both products were administered with stavudine and lamivudine - two nucleoside reverse transcriptase inhibitors (NRTI) - to 653 patients new to HIV therapy. Through 24 weeks of therapy, the proportion of patients with HIV RNA <50 copies/ mL was 65% in the group receiving Kaletra, and 60% in the nelfinavir group. Additionally, the mean increase from baseline in CD4 cell count was 154 cells/ mm3 for the Kaletra group and 150 cells/ mm3 for the nelfinavir group.
Study 720 is an ongoing, randomized, blinded, multicenter trial evaluating treatment with Kaletra at three dose levels (plus lamivudine and stavudine) in 100 patients. Through 72 weeks of treatment, the proportion of patients with undetectable levels of the virus (HIV RNA <400 copies/ mL) was 80% and the mean increase from baseline in CD4 cell count was 256 cells/ mm3 for the 51 patients originally receiving a 400/ 100 mg dose of Kaletra.
Patients Who Have Received Prior Antiretroviral Therapy
Study 765 is an ongoing, randomized, blinded, multicenter trial evaluating treatment with Kaletra at two dose levels plus nevirapine and two NRTIs. The treatment group consisted of 70 patients who had not previously taken a non-nucleoside reverse transcriptase inhibitor (NNRTI) but were single protease inhibitor experienced. Through 72 weeks of treatment, the proportion of patients with HIV RNA <400 copies/ mL was 75% and the mean increase from baseline in CD4 cell count was 174 cells/ mm3 for the 36 patients receiving the 400/ 100 mg dose of Kaletra. (from FDA Label)
Possible side effects of Kaletra include (but are not limited to) the following:
Additionally, some patients taking Kaletra can develop serious problems with their pancreas. Patients should immediately inform their doctor if nausea, vomiting, or abdominal pain occurs, as these may be signs of pancreatitis.
Lopinavir, an inhibitor of the HIV protease, prevents cleavage of the Gag-Pol polyprotein, resulting in the production of immature, non-infectious viral particles. (from FDA label)
For additional information on Kaletra, please visit the web site of Abbott Laboratories.