of acting rationally and making decisions based on the best scientific evidence so that the long-term durability of individual patient regimens and the sustainability of ART programs will not be jeopardized. A lack of careful planning could create conditions conducive to treatment failure and the development of drug-resistant virus, leading ultimately to disillusionment and demoralization. While avoiding delays in delivering treatment, the international and national communities of donors, planners, and providers must remain vigilant in seeking continued improvements and necessary course corrections to maximize treatment benefits and extend as many lives as possible. Failed programs using first-line regimens, regardless of the reasons for failure, necessitate much more costly and less-sustainable second-line regimens or result in the termination of ART for affected patients; they also limit treatment opportunities for others afflicted today and for the tens of millions of additional HIV-infected persons anticipated over the next decade or so.

Ultimately, the best lessons may be learned from ART scale-up itself. Critical to the long-term success of these programs will be their ability to recognize where both desired outcomes and failures are encountered. These programs, their leaders, and their funders will require sufficient flexibility and commitment to quality to ensure that changes, when necessary, are made.

For now, ART programs already in various stages of implementation throughout the developing world provide advice worth heeding (see Figure 1-2). Some of these programs have met with success, others with high rates

FIGURE 1-2 Estimated worldwide coverage with antiretroviral treatment at the end of 2003.

SOURCE: WHO, 2004.