The largest and most expensive clinical trial of an HIV vaccine ever is now under way in Thailand. Three Penn scientists and colleagues from 17 other universities and research institutes across the country have argued that the mega-trial is a waste of money and illustrates the need to rethink the way such trials are approved.

In a letter that appeared in the Jan. 16 issue of Science, Robert Doms, chair of microbiology, Jim Hoxie, professor of hematology and oncology, Neal Nathanson, professor emeritus of microbiology and 19 other scientists called for better integration of the latest medical science into the approval process.

The letter has stimulated a worldwide discussion about how to proceed with HIV clinical trials and intense media interest both in the United States and in Thailand. (The U.S. government is paying for the roughly $120 million study.) Stories about the letter and the controversy it sparked have run on BBC Thailand and in The Washington Post, USA Today and The Boston Globe, among other outlets.

The controversy erupted over the components of the proposed vaccine, VaxGen’s monomeric gp120 and Aventis Pasteur’s ALVAC. While the study’s proponents believe the combination of the two will provide a defense from infection by HIV, Doms pointed to the disappointment and failures of each in previous trials.

“We aren’t aware of any evidence to suggest these components provide any synergy when combined that does not happen with each separately,” said Doms. “A smaller trial could be used to verify [the combination] first, before this very large trial.”

Doms added, “When this trial was initially planned, there was no knowledge that one of the two components could fail utterly in initial studies, yet the trial is going on as planned.”

Since no clear path to an HIV vaccine has yet emerged, Doms said that the money could be better spent on numerous smaller trials. “The standard NIH research grant may cost around $300,000 per year for five years. You could easily fund 50 to 70 research projects using these funds. And the money is most needed back in research.”