Efficacy and safety of abacavir plus lamivudine versus didanosine plus stavudine when combined with a protease inhibitor, a nonnucleoside reverse transcriptase inhibitor, or both in HIV-1 positive antiretroviral-naive persons.

PURPOSE: The combination of abacavir + lamivudine (ABC+3TC) versus didanosine + stavudine (ddI+d4T), each combined with other classes of antiretrovirals (ARVs) in ARV-naive patients, was compared for the combined endpoint of time to plasma HIV RNA >50 copies/mL (at or after the 8-month visit) or death (primary endpoint) in a nested substudy of an ongoing multicenter randomized trial. METHOD: The substudy enrolled 182 patients; mean HIV RNA and CD4+ cell counts at baseline were 5.1 log10 copies/mL and 212 cells/mm3, respectively. RESULTS: After a median follow-up of 28 months, rates of primary endpoint were 57.2 and 67.8 per 100 person-years for the ABC+3TC and ddI+d4T groups (hazard ratio [HR]=0.81, 95% confidence interval [CI] 0.58-1.14, p=.23). CONCLUSION: There was a trend for treatments containing ABC+3TC to be better than treatments containing ddI+d4T with respect to HIV RNA decreases, CD4+ cell count increases, and tolerability.

The rationale and design of the CPCRA (Terry Beirn Community Programs for Clinical Research on AIDS) 058 FIRST (Flexible Initial Retrovirus Suppressive Therapies) trial.

The CPCRA (Terry Beirn Community Programs for Clinical Research on AIDS) 058 FIRST (Flexible Initial Retrovirus Suppressive Therapies) trial is a large, long-term, randomized, prospective comparison of three different antiretroviral strategies in highly active antiretroviral therapy-naïve, HIV-1-infected persons. The trial was designed as a flexible framework upon which other studies could be added to answer more limited, but still important, questions. This article presents the study design, discusses the challenges we have faced in implementing the trial, and describes our preliminary experiences. Control Clin Trials 2001;22:176-190

A randomized trial of daily and thrice-weekly trimethoprim-sulfamethoxazole for the prevention of Pneumocystis carinii pneumonia in human immunodeficiency virus-infected persons. Terry Beirn Community Programs for Clinical Research on AIDS (CPCRA)

We enrolled 2,625 human immunodeficiency virus-infected patients into a randomized trial to assess the efficacy and tolerability of daily vs. thrice-weekly trimethoprim-sulfamethoxazole (160 mg/800 mg) for prophylaxis of Pneumocystis carinii pneumonia (PCP). The rate of PCP was 3.5 and 4.1 per 100 person-years in the daily and thrice-weekly groups, respectively, with a relative risk (RR) of 0.82 (95% confidence interval [CI], 0.61-1.09; P = .16) (RR of <1.0 favors daily trimethoprim-sulfamethoxazole). The RR for PCP determined by on-treatment analysis was 0.59 (P = .03). The RR for death was 0.91 (P = .12); for bacterial pneumonia, 0.82 (P = .06); and for combined PCP and bacterial pneumonia, 0.84 (P = .04). Discontinuation due to adverse events occurred more commonly in the daily trimethoprim-sulfamethoxazole group (RR, 2.14; 95% CI, 1.73-2.66; P < .001). Overall estimates for efficacy end points favored daily trimethoprim-sulfamethoxazole, although rates of intolerance were higher among patients receiving that dose. Daily trimethoprim-sulfamethoxazole may offer advantages as a first choice for PCP prophylaxis; thrice-weekly dosing is an appropriate option for patients intolerant of the daily dose.

Atovaquone compared with dapsone for the prevention of Pneumocystis carinii pneumonia in patients with HIV infection who cannot tolerate trimethoprim, sulfonamides, or both. Community Program for Clinical Research on AIDS and the AIDS Clinical Trials Group.

BACKGROUND: Although trimethoprim-sulfamethoxazole is the drug of choice for the prevention of Pneumocystis carinii pneumonia, many patients cannot tolerate it and must switch to an alternative agent. METHODS: We conducted a multicenter, open-label, randomized trial comparing daily atovaquone (1500-mg suspension) with daily dapsone (100 mg) for the prevention of P. carinii pneumonia among patients infected with the human immunodeficiency virus who could not tolerate trimethoprim-sulfamethoxazole. The median follow-up period was 27 months. RESULTS: Of 1057 patients enrolled, 298 had a history of P. carinii pneumonia. P. carinii pneumonia developed in 122 of 536 patients assigned to atovaquone (15.7 cases per 100 person-years), as compared with 135 of 521 in the dapsone group (18.4 cases per 100 person-years; relative risk for atovaquone vs. dapsone, 0.85; 95 percent confidence interval, 0.67 to 1.09; P=0.20). The relative risk of death was 1.07 (95 percent confidence interval, 0.89 to 1.30; P=0.45), and the relative risk of discontinuation of the assigned medication because of adverse events was 0.94 (95 percent confidence interval, 0.74 to 1.19; P=0.59). Among the 546 patients who were receiving dapsone at base line, the relative risk of discontinuation because of adverse events was 3.78 for atovaquone as compared with dapsone (95 percent confidence interval, 2.37 to 6.01; P<0.001); among those not receiving dapsone at base line, it was 0.42 (95 percent confidence interval, 0.30 to 0.58; P<0.001). CONCLUSIONS: Among patients who cannot tolerate trimethoprim-sulfamethoxazole, atovaquone and dapsone are similarly effective for the prevention of P. carinii pneumonia. Our results support the continuation of dapsone prophylaxis among patients who are already receiving it. However, among those not receiving dapsone, atovaquone is better tolerated and may be the preferred choice for prophylaxis against P. carinii pneumonia.

Data analysis issues for protocols with overlapping enrollment.

Many persons with HIV require and take several medications. The efficacy and safety of many of these medications are uncertain. Usually limited data on drug interactions are available. Thus simultaneous and sequential enrolment of patients into multiple studies is desired for reasons of science and efficiency. This paper discusses the analysis of data arising from coenrolment in multiple studies sponsored by the Community Programs for Clinical Research on AIDS (CPCRA). Factorial designs and those in which patients are sequentially instead of simultaneously randomized are compared. Approaches to data analysis, based on intention-to-treat, for individual and pairs of trials are described. An antiretroviral trial and a trial for prophylaxis of Pneumocystis carinii pneumonia (PCP) are used for illustration. We conclude that such analyses may yield useful information on drug interactions and that a more vigorous coenrolment policy should be pursued in AIDS research.