The greatest global epidemic in recent times, HIV / AIDS, is a socio-health problem of enormous magnitude. Since its appearance, the number of cases has gradually increased until the discovery of a large number of drugs that, associated in tri or tetratherapy, are able to control the infection. However, the cost of antiretroviral treatment, close to 1,000 euros per patient per month, makes access difficult for many patients.
The treatment of HIV / AIDS has changed radically in recent years. The first drug that gave hope to patients infected with the human immunodeficiency virus (HIV) was zidovudine, which, as monotherapy, was an important improvement in the fight against this new disease.
Subsequently, more antiretroviral drugs appeared, and it was observed that their joint administration produced notable increases in the therapeutic response. Now, these drugs have from the outset been a great cost to which society must confront.
The emergence of therapeutic combinations of two or more antiretrovirals has managed to multiply the precise total cost for antiretroviral drugs by several units, causing a serious deterioration to the state coffers to the point that, at present, and since their appearance, all these medicines They are classified as specialties for hospital use, not being allowed to be dispensed through pharmacies but through hospital pharmacy services.
The transfer of antiretroviral drugs from the community pharmacy to the hospital has meant:
On the one hand, a large workload for these centers, since each hospital makes its dispensation to all patients included in the treatment program who reside in the area of influence of the center.
On the other hand, outpatient dispensing in hospital centers has led to a significant reduction in acquisition costs because, at least, these are reduced in the margin of contribution to the benefit of pharmacies and pharmaceutical distributors, which are fixed legally this amount.
Notwithstanding the above, the cost of treating this disease does not correspond faithfully with the cost of acquiring the precise drugs, but there is a great diversity of costs that must be taken into account when carrying out the pharmacoeconomic assessment of the treatment of the disease.
HIV AIDS. It is for this reason that the dispensing in pharmacies of hospitals, instead of in pharmacies, although it supposes a decrease of the acquisition costs, would not be the best way to reduce the global cost of the disease.
The first step is to analyze in its entirety the costs involved in the treatment. The most relevant are, in addition to the one produced by the drugs, those corresponding to different tests and explorations and the one originated by the hospitalizations of the patients.
The next step lies in the analysis of the causes that cause a therapeutic failure, such as non-adherence to treatment, the resistance generated to drugs and opportunistic infections and other complications.
All this means that in the absence of therapeutic success, no matter how much the cost of acquiring the drugs used would be reduced by actions of any kind, efficiency would tend to zero, giving way to these measures.
Currently, there are two groups of antiretroviral drugs 1 (Table 1): reverse transcriptase inhibitors (ITI), which are divided into nucleoside analogs (NRTIs) and non-nucleoside analogues (NNRTIs), and protease inhibitors (IP) ).
They act by inhibiting HIV replication by blocking the copy of viral RNA in DNA. One subgroup are nucleoside analogues (NIT) and others are not (NNRTI). The nucleoside analogs include abacavir (ABC), didanosine (ddI), stavudine (d4T), lamivudine (3TC), aalcitabine (ddC), and zidovudine (AZT); among the non-analogues are efavirenz and nevirapine.
They act by inhibiting HIV proteinase, an enzyme that produces specific breaks in viral precursor proteins in infected cells, to produce infectious viral particles. They are the last antiretrovirals that have appeared. Among them are amprenavir, indinavir, nelfinavir, ritonavir and saquinavir.
Cost of antiretrovirals
The costs of acquisition of drugs are large: between 2.67 and 20.99 euros for each day of treatment. This has led us to think, from the beginning, whether the pharmacoeconomic parameters of antiretroviral treatment are within the usual ranges, since this is the initial way to evaluate the true value of a new therapy.
Schulman et al 2 performed a pharmacoeconomic analysis of zidovudine (AZT) in its early stages, based on data obtained from the AIDS Clinical Trials Group Protocol 019 , estimating that AZT therapy had an incremental cost of $ 2,653 and a cost of year of life saved between $ 6,553 and $ 70,526 (depending on which epidemiological model of the long-term effect was chosen). The estimation of a ratio with the first antiretroviral, similar to that of other common treatments, showed the efficiency of the treatment.
Chancellor et al 3 subsequently analyzed the combination of AZT with lamivudine (3TC) versus AZT only from a cohort of patients treated at the Chelsea and Westminster Hospital in London, finding an incremental cost of 6,276 pounds sterling per year of life saved, which also falls within the internationally accepted ranges.
Subsequently, the combination of two drugs, the association of three or more, high activity antiretroviral therapy (HAART) appeared, which resulted in a significant improvement in the effectiveness of the treatment. But the question about the real value of these compositions gained even more strength, as their cost increased significantly. Again, the pharmacoeconomic parameters of the HAART showed that these treatments enjoyed incremental cost/effectiveness ratios that fell within the margins accepted in developed countries for other therapies.