1. Cost of providing anti-retroviral therapy

Available data concerning the costs of providing ARV therapy are presented in two separate sections: the first presents the costs of the ARV drugs; the second presents the details on the other costs associated with providing them. A third section highlights other costs which may be important, especially in developing countries.

The cost of the ARVs themselves are shown in Table 1 below. The most recent figures suggest that, at market prices, AZT costs US$ 1.5/100mg tablet. Since the standard regimen involves 500mg/day, this means that the daily per patient cost is US$ 7.5, the average monthly cost per patient is US$ 228, and the annual cost per patient is US$ 2 738. This is considerably less than in the late 1980s, when the annual per patient cost of AZT was reported to be US$ 10 000 (Sabatier et al, 1989).

Meanwhile, three of the newer "nucleoside reverse transcriptase inhibitors" are slightly cheaper (didanosine costs US$175 per month, zalcitabine US$220 per month, and lamivudine US$214 per month), while a fourth - stavudine - is slightly more expensive at US$232 per month. The even more recent "protease inhibitors" are considerably more: ritonavir costs US$692 per month, saquinavir US$545 per month, and idinavir US$533 per month. The one "non-nucleoside reverse transcriptase inhibitor" - nevirapine - is at the lower end of the spectrum of costs, at US$272 per month. Double combination therapies range in costs from US$403 to US$ 773 per month, while the triple combination therapies range from US$662 to US$993, increasing to up to US$1 465 if ritonavir is added.

These costs are substantial. However, it is important to note that large reductions in these costs may be possible when drugs are purchased in bulk. To illustrate this, Table 2 below shows the drug costs which have been negotiated in Uruguay on the basis of bulk-purchase (Abreu, personal communication). This shows that annual treatment costs approximately two-thirds of those quoted above have been achieved for two of the drugs, and the cost of AZT has been reduced to 28% of the US market price quoted above.

In addition to drug costs, other important costs associated with providing therapy include: HIV tests to establish whether someone is HIV+ and hence eligible for therapy; pre- and post-test counseling; regular out-patient visits to monitor patients for side-effects and to issue supplies of drugs; laboratory tests such as CD4 counts, complete blood counts, viral loads, and chemistry panels to monitor patient health status; and out-patient visits/hospitalizations associated with adverse drug effects. Few data are available concerning their cost. Those cost data which could be accessed are shown in Table 3.

* assumed to be required once/month by Bozette et al and quarterly by Schulman et al ** assumed to be required once/month by both Bozette et al and Schulman ***assumed to be required quarterly by Schulman et al

There are also some additional costs which may be involved in providing ARV therapy, especially in developing countries, and it is worth highlighting these. Many of the costs quoted in Table 3 above are based on US cost data, where the costs of shipping equipment and supplies will be relatively low because they can be domestically produced. In developing countries where these items will probably have to be imported from countries a considerable distance away, costs are likely to be higher.

In addition, in developing countries laboratories may have to be strengthened considerably if they are to be capable of providing the diagnostic and monitoring support necessary for provision of ARV therapy. This could include installation of air-conditioners and back-up generators to cope with electricity cuts, and proper maintenance contracts. Developing such capacity may have large costs attached to it.