An attempt to give the US Food and Drug Administration (FDA) more power to force companies to carry out post-marketing studies – also known as Phase IV testing – has been defeated in the House of Representatives.

The amendment had been piggybacked onto a House appropriations bill in an attempt to get it through, shortly after the publication of a Government Accountability Office report which found there were deficiencies in the way the FDA monitored the safety of drugs once approved for marketing.

But the amendment was stripped from the legislation after it was decided that it amounted to legislation though the appropriations process – something that is not permitted under House rules.

Representative Rosa DeLauro, (D-Conn), who proffered the amendment, said after the amendment was killed that “the FDA lacks any real authority to order a company to conduct a safety study of a drug already on the market, even when serious safety concerns are raised.”

The GAO report was requested in the wake of high-profile drug safety scares, including Merck & Co's withdrawal of painkiller Vioxx (rofecoxib) from the marketplace in 2004 after it was linked to an increased risk of heart attack and stroke.

Another bill that would boost the FDA’s powers in demanding Phase IV studies, put forward by Senators Chuck Grassley and Christopher Dodd, remains on the table, while the Senate Health Education Labor and Pensions Committee (HELP) is also working on comprehensive legislation to revamp drug safety at the FDA.

Meanwhile, another amendment put forward by Representative Maurice Hinchey (D-New York) survived and is going forward. This would limit the number of external experts with drug company ties who vote on FDA advisory committees, something the agency itself has opposed.

At the moment, the agency can grant waivers to scientists or doctors with conflicts of interest, allowing them to serve on the panels. It claims its entire advisory committee structure would be compromised if the amendment goes though.

- Meanwhile Sen Grassley has asked the US Securities and Exchange Commission (SEC) to look into allegations that physicians involved with clinical trials have sold information to financial analysts in breach of insider trading laws.