Susceptibility of HIV-1 to tipranavir and other antiretroviral agents in treatment-experienced patients: The UTILIZE Study.

OBJECTIVES: The primary objective was to assess HIV-1 susceptibility to the protease inhibitor (PI) tipranavir and other antiretroviral (ARV) agents among treatment-experienced patients (TEP). Secondarily, clinicians' use of resistance testing was examined. METHODS: UTILIZE was an observational study conducted at 40 sites in the United States. Patients currently failing a PI-based regimen were randomized to receive either a genotype (GT) or combined phenotype-genotype test (PGT) and a treatment decision was made at the second study visit. RESULTS: 246 patients enrolled, 236 had resistance test results, and 139 (59%) had evidence of HIV-1 resistance to >or=1 PI. Among these 139 patients, more than 50% had viruses that remained sensitive to tipranavir and darunavir, whereas susceptibility to other PIs was markedly lower (<22%). Increasing prior PI exposure was associated with reduced susceptibility to most ARV agents. After obtaining resistance test results, 83% of patients changed therapy. Newly available or investigational ARVs were used frequently. The reason investigators most often cited for changing therapy was the patient resistance test results (82%) and the most common reason for not changing therapy was the inability to construct an active regimen. The majority of patients who exhibited PI resistance received two or more active agents in the new regimen. CONCLUSIONS: Overall, 59% of TEPs failing a PI-based regimen had HIV-1 with PI resistance. The majority of these patients' viruses remained sensitive to either tipranavir or darunavir. Investigators used results from resistance assays to construct a new regimen, frequently with newer agents. In PI-experienced patients, tipranavir and darunavir remain the most likely available active PIs.

Randomized, controlled study of the effects of a short course of prednisone on the incidence of rash associated with nevirapine in patients infected with HIV-1.

OBJECTIVE: To examine the effect of 2 weeks of treatment with prednisone on the incidence of nevirapine-associated rash in HIV-1-infected patients receiving combination antiretroviral therapy. METHODS: This was a 24-week, prospective, randomized, open-label, international study. Patients were randomized to receive nevirapine plus open-label prednisone (40 mg once daily for 14 days) (n = 69) or nevirapine alone (n = 69). All patients received at least two other antiretroviral drugs. Nevirapine was administered at the lead-in dosage of 200 mg once daily. After the initial 2 weeks of the study, the nevirapine dosage was increased to 200 mg twice daily. RESULTS: During the first 6 weeks of treatment, rash was not reduced in the patients who received prednisone: prednisone treatment group, 23 (33%)/69; nonprednisone treatment group, 13 (19%)/69 (one-tailed Fisher exact test for prednisone reducing the incidence of rash, p =.984). There tended to be more severe rashes (7% versus 1%, respectively) and more therapy discontinuations due to rash (16% versus 9%, respectively) in the prednisone treatment group than in the nonprednisone treatment group. Risk factors for rash included higher pretreatment CD4 cell count, lower HIV-1 RNA level, female sex, and higher trough nevirapine concentrations. The prednisone treatment group had a marked increase in the median CD4 cell count in the first 2 weeks, which stabilized at a level similar to that in the nonprednisone treatment group. HIV-1 RNA responses were similar between the two groups. Treatment-naive patients had similar decreases in plasma HIV-1 RNA levels at week 24: approximately 2.3 log(10) copies/mL. CONCLUSIONS: This study demonstrated that 2 weeks of concomitant therapy with prednisone does not decrease the occurrence of nevirapine-associated rash. The use of prednisone is not recommended to prevent rash in patients receiving nevirapine. Prednisone administration had no adverse effects on the virological responses or on CD4 cell count changes at 24 weeks.

Pharmacokinetic interaction between nevirapine and ethinyl estradiol/norethindrone when administered concurrently to HIV-infected women.

OBJECTIVE: To determine the effects of nevirapine (NVP), a nonnucleoside reverse-transcriptase inhibitor of HIV-1 and P450 inducer, on the pharmacokinetics (PK) of ethinyl estradiol (EE)/norethindrone (NET), a widely used oral contraceptive, and to assess the effects of EE/NET on the steady-state PK of NVP. METHODS: Ten HIV-1-infected women underwent intensive PK sampling after single-dose administration of EE/NET (days 0-1). Oral NVP 200 mg once daily (days 2-15), followed by 200 mg twice daily (days 16-29), was added to background potent antiretroviral therapy. On day 30, intensive PK sampling was performed after concurrent administration of NVP 200 mg and a single dose of EE/NET. RESULTS: Concomitant administration of NVP at steady state with EE/NET resulted in a significant (29%) median reduction in the area under the plasma concentration time curve (AUC(infinity)) and a significant reduction in mean residence time (MRT) and half-life (t(1/2)) of EE. There was a significant (18%) median reduction in the AUC(infinity) for NET that was not associated with a detectable change in NET C(max), MRT, or t(1/2). CONCLUSION: Oral contraceptives should not be the primary method of birth control in women of child-bearing potential who are treated with NVP.