The US Food and Drug Administration (FDA) is facing a lawsuit filed by two public health advocacy organizations for its failure to provide clinical trial information on 'blockbuster' Hepatitis C drugs.

The June 25 lawsuit involves a Freedom of Information request for the information on Gilead Sciences' Harvoni and Sovaldi, the two Hepatitis C drugs known to have not only very high cure rates, but also very high costs.

A 12-week treatment costs $94,500 for Harvoni and $84,000 for Sovaldi. The complaint stresses that unless the clinical trial data is provided, safety, efficacy and cost effectiveness of the drugs will remain to be not understood.

According to a Gilead spokeswoman, the lawsuit is being reviewed by the drug maker. FDA declined to comment.

Treatment Action Group and the Global Health Justice Partnership requested for the date from Gilead late last year. However, they were not able to obtain the information they asked for and did not get a response. They further sought assistance from the FDA from whom approval was given for the drugs. The FDA denied this request for "expedited processing." It can take 18 to 24 months to look over the information.

The request for the clinical trial data has stirred up much concern among consumer groups, academics and drug makers. The lawsuit's goal is for independent researchers to study the results and further improve patient treatment or even to possibly lower the costs. Industry, however, says that this could "compromise trade secrets" as well as patient confidentiality.

Health groups are also concerned about the possible side effects of the drugs, and want to know more about the different responses of different patients involved in the clinical trials.

Treatment Action Group Tracy Swan, for instance, points out that there have been relapses in a trial for Harvoni that were only experienced by African-Americans. 

"This delay will leave doctors and patients in the dark for too long," stresses Yale Professor Amy Kapczynski. She also notes how thousands of prescriptions are written by doctors each week, while state and health care program budgets are strained since the FDA already collects the data, as long as it is promptly disclosed, treatment choices can become more informed, with "real and immediate consequences for public health and spending."