Costs of intermittent versus continuous antiretroviral therapy in patients with controlled HIV infection: a substudy of the ANRS 106 Window Trial

Background: Structured treatment interruptions in chronic HIV infection have been explored as a drug-sparing strategy to reduce drug-related adverse events and costs while maintaining CD4 cell counts at a level high enough to prevent the risk of disease progression.

Objectives: To test the hypothesis and put a figure on the reduction in total medical costs, we conducted a cost study analysis in the setting of a randomized open-label study comparing an intermittent to a continuous antiretroviral regimen.

Patients and methods: Four hundred three HIV-1-infected adults who were tolerating highly active antiretroviral therapy (HAART), with a nadir CD4 count of 100 cells per microliter or more and a CD4 count above 450 cells per microliter at screening, were randomly assigned to switch to a fixed 8-week off, 8-week on intermittent treatment (IT) or to maintain their current treatment (CT) strategy. The proportions of patients who reached a CD4 cell count below 300 cells per microliter through 96 weeks (primary end point) were not significantly different between arms. Costs were estimated from the viewpoint of the payer over the 96-week study period. Unit costs were provided from the national reimbursement schedules for hospital inpatient and outpatient admissions and ambulatory visits and the national selling price for medications. All analyses were performed on an intention-to-treat basis.

Results: Complete cost data were available for 391 patients (197 patients in the IT and 194 in the CT arms). The mean cost in euros (Euro) per patient over the 96 weeks of follow-up (excluding protocol-driven costs) was 9738 in the IT arm vs. 16,162 in the CT arm, a 6424 difference almost entirely due to the difference in HAART cost. Mean protocol-driven costs represented Euro290 in the IT vs. Euro280 in the CT arm. The use of IT achieved a 40% reduction in the total cost of HAART.

Conclusions: Reducing by 40% the cost ofHAART medications in a treatment interruption strategy did not increase the costs related to adverse events or consultations.