Demonstraters in Nairobi, Kenya on Thursday, Dec.
Demonstraters in Nairobi, Kenya on Thursday, Dec. 9, 2010, protest a potential free trade area agreement between the EU and India that could see cheap generic anti-AIDS drugs phased out. (AP Photo/Khalil Senosi)

A review of the guidelines for HIV treatment in poor countries finds priority should go to starting that treatment early.

"What we learned from a clinical standpoint, as well as a cost-effective standpoint, is that earlier anti-retroviral therapy improved five-year survival dramatically and resulted in a longer life expectancy," says Rochelle Walensky, an infectious disease researcher from Harvard.

Treatment for HIV has become more widespread, especially in poorer countries. It's also become cheaper, as pharmaceutical companies have lowered their prices for life-saving anti-retroviral drugs. But these drug regimens are still expensive and many countries are looking to create the biggest impact with scarce resources. That's where World Health Organization guidelines come in.

"If you read the guidelines, they talk about how you can prioritize by the need to make sure that everybody gets the same thing," Walensky says, "by the intervention that's going to save us the most lives. We need to prioritize by the intervention is going to give us the most bang for the buck or be most cost-effective."

Walensky and her colleagues used computer programs to model the most cost-effective disease interventions, as well as collected data from clinics in Africa and India about what works best. But cost-effective doesn't always mean affordable, especially for governments in poor countries. Countries still have to make difficult choices about how much treatment they can afford.

However, Walensky notes that first-line anti-retrovirals - those medicine given to newly diagnosed patients that can stave off symptoms for years - are much cheaper than they were a decade ago. "Second-line regimens have come down quite a bit but not to the level of first-line and countries are having a hard time affording them and increasingly over time, people are going to fail first-line therapy and they're going second-line therapy and then, eventually, they're going to need third-line therapy, some of them."

According to Walensky, history has shown that drug prices can come down when international pressure is applied to drug makers. That would change the calculus for governments. But for now, she says, countries should focus on treating as many people as they can, as early as possible.

Her paper is published in the online journal PLoS Medicine.