Aug. 18 (Bloomberg) -- Half of China’s AIDS patients stopped responding to treatment over five years and didn’t have access to the back-up drugs available in developed nations, researchers found.

Among 48,785 HIV patients who received free treatment under a government program from 2002 to 2008, the drugs curbed AIDS- related deaths but failed to treat 50 percent of the group over the period, researchers led by Fujie Zhang at China’s Center for Disease Control and Prevention found. The results are similar to those for other low- and middle-income countries, they said.

Since 2002, people with HIV in China have been able to receive free treatment for the AIDS-causing virus with generic versions of medicines such as GlaxoSmithKline Plc’s Retrovir and Epivir and Boehringer Ingelheim GmbH’s Viramune. More expensive second-line pills that weren’t readily available in China are now being introduced to the national treatment program, Zhang and colleagues wrote in Annals of Internal Medicine today.

“The challenge will be to scale up access in a way that does not merely postpone treatment failure and the need for third-line treatment,” they wrote.

About 700,000 people in China had HIV at the end of 2007, according to estimates by UNAIDS, the United Nations’ AIDS- fighting agency. Among those, 223,501, or 32 percent, have been reported.

The study was funded by China’s health ministry, the U.S. National Institutes of Health and the U.S. Centers for Disease Control and Prevention.

To contact the reporter on this story: Simeon Bennett in Singapore at sbennett9@bloomberg.net

Last Updated: August 17, 2009 17:00 EDT