Switch to an antiretroviral treatment of expected lower potency after effective highly active antiretroviral therapy (HAART)

Antiretroviral Therapy in the??Real World

OBJECTIVE AND METHODS

The aim of our study was to analyse retrospectively the nature and frequency of antiretroviral prescriptions for 990 HIV-infected patients followed at our outpatient centre in Bologna, Italy, from January 2003 to March 2004. The main focus of the study was to identify the most commonly prescribed combinations and their related expenses, in order to identify the most competitive treatment regimens with regard to costs. Prescriptions were given directly to patients at monthly intervals, and drug treatment adherence data was stored in an electronic database. Antiretroviral regimens administered for the longest period to each patient during the 15 months of the study were selected for the study. All patients treated for <9 consecutive months and/or with treatment adherence levels <90% were excluded. Physicians assessed antiretroviral therapy at least quarterly according to efficacy and safety criteria, but not in terms of pharmacoeconomic considerations. Direct pharmacy expenses were obtained for the 24 most commonly used therapeutic regimens, covering 80.1% of patients.

RESULTS

The zidovudine-lamivudine-efavirenz combination proved to be the most prescribed combination (7.3%), followed by zidovudine-lamivudine- nevirapine (7.1%), lamivudine-stavudine (6.2%), zidovudine-lamivudine- lopinavir-ritonavir (5.2%), didanosine-stavudine-lopinavir-ritonavir (4.8%), and lamivudine-stavudine-nevirapine (4.7%). Anti-HIV combinations varied from a minimum yearly cost of euro3895.6 for lamivudine-stavudine to euro9422.8 for the zidovudine-lamivudine-lopinavir-ritonavir combination (+241.9%) [year of costing 2003]. There was a significant difference between the two first-line regimens for antiretroviral-naive subjects, with lopinavir-ritonavir-based combinations costing more than euro9000 per patient/year compared with efavirenz-containing combinations, which were 28% less expensive. Mean daily costs varied substantially, from a minimum of euro10.7 per day for lamivudine-stavudine to a maximum of euro25.8 per day (+241.1%) for zidovudine-lamivudine-lopinavir-ritonavir. Regimens based on non-nucleoside reverse transcriptase inhibitors (NNRTIs) were less costly than most of those including protease inhibitors (PIs). The increased expense of each combination was compared with the cheapest therapeutic selection (lamivudine-stavudine), and costs of all triple combinations were also compared. Regimens based on NNRTIs accounted for 29.3% of our cohort (nevirapine-containing therapies 15.1%, and efavirenz-based ones 14.2%), while PIs were used in the majority of cases (37.3%), with lopinavir-ritonavir as the leading combination (13.6% of patients), followed by nelfinavir (9.9%) and indinavir (9.2%). When drug-related costs were examined, dual nucleoside analogues showed the lowest expense (euro10.7-euro11.6 per day), while triple nucleoside/nucleotide analogue combinations cost nearly twice as much (euro18.5-euro20.4 per day). Among the NNRTIs, there were comparable costs for nevirapine-based combinations (euro18.3-euro18.7 per day), while efavirenz-including regimens were 10% more costly (euro19.2-euro20.l per day). A very broad range of combinations and related costs were found with PIs, but apart from indinavir and saquinavir combinations (euro15.7-euro21.7 per day), all other regimens had a higher daily cost (from euro22.0 per day for ritonavir-based regimens to euro23.4-euro24.3 per day for nelfinavir combinations, and up to euro24.9-euro25.8 per day with lopinavir-ritonavir). When considering nelfinavir- and lopinavir-containing combinations, the difference compared with NNRTI-based regimens varied from 41% when nevirapine- and lopinavir-ritonavir were compared, to 11.6% when efavirenz and nelfinavir were compared.

CONCLUSIONS

Investigations that link prescribing patterns and related costs in the setting of HIV disease therapy are needed to improve patient management and help with the planning of healthcare resource allocation.

HIV disease and advanced age: an increasing therapeutic challenge

The mean age of patients at both first HIV detection and AIDS diagnosis is progressively rising over time. However, reliable epidemiological estimates, clinical data or controlled therapeutic and outcome figures are lacking for elderly patients, especially with regard to laboratory and clinical response to antiretroviral therapy, treatment tolerability, drug-drug interactions, short- and long-term toxicity, and interactions with underlying illnesses and concurrent pharmacological treatment. In fact, the large majority of randomised, controlled trials evaluating and comparing new antiretroviral drugs or anti-HIV therapeutic strategies, as well as antimicrobial treatment or chemoprophylaxis of HIV-related complications, either excluded patients with advanced age and/or concurrent disorders or did not offer substudies or detailed data analysis focusing on older patients compared with younger ones. The life expectancy of HIV-infected persons receiving highly active antiretroviral therapy (HAART) is now extended (approaching that of the general population), so that the definition of AIDS has lost its epidemiological and clinical significance thanks to the immune reconstitution resulting from potent antiretroviral therapy. However, an ever-increasing number of individuals aged > or =50 years with HIV infection is expected in the coming years, as a result of both increased survival of patients with treated disease and delayed recognition of individuals with occult HIV disease. The limited data available about combined antiretroviral therapy in the elderly seem to show an overlapping virological success rate but a slower and blunted immune recovery compared with younger patients. Thymic output, however, seems somewhat preserved even in adulthood and may contribute to the reconstitution of most of the quantitative and functional T cell abnormalities caused by HIV disease. More attention must be paid to underlying end-organ disorders, as well as expected pharmacological interactions and combined drug toxicity that may interfere with HAART efficacy and patients' compliance with recommended regimens and could lead to increased adverse effects. The available guidelines for antiretroviral treatment and therapy and prophylaxis of AIDS-related illnesses should be regularly updated and should include problems related to HIV disease in an aging population. Specific trials or substudies focusing on older people are warranted to obtain controlled data on all issues of antiretroviral therapy in the elderly, including time and mode of initiation, and modification and salvage HAART regimens. Antiretroviral drug dosage adjustment to take into account underlying pathological conditions or other pharmacological treatments is another emerging issue.