Zidovudine - Patent Issues

Patent Issues

The patents on AZT have been the target of some controversy. In 1991, Public Citizen filed a lawsuit claiming that the patents were invalid. Subsequently, Barr Laboratories and Novopharm Ltd. also challenged the patent, in part based on the assertion that NCI scientists Samuel Broder, Hiroaki Mitsuya, and Robert Yarchoan should have been named as inventors, and those two companies applied to the FDA to sell AZT as a generic drug. In response, Burroughs Wellcome Co. filed a lawsuit against the two companies. The United States Court of Appeals for the Federal Circuit ruled in 1992 in favor of Burroughs Wellcome, claiming that even though they had never tested it against HIV, they had conceived of it working before they sent it to the NCI scientists. This suit was appealed up to the Supreme Court of the US, but they declined to formally review it. In 2002, another lawsuit was filed over the patent by the AIDS Healthcare Foundation.

However, the patent expired in 2005 (placing AZT in the public domain), allowing other drug companies to manufacture and market generic AZT without having to pay GlaxoSmithKline any royalties. The U.S. FDA has since approved four generic forms of AZT for sale in the U.S.

In November 2009 GlaxoSmithKline formed a joint venture with Pfizer which combined the two companies' HIV assets in one company called ViiV Healthcare. This included the rights to Zidovudine.