The AIDS Healthcare Foundation has filed an amended lawsuit in federal court against drugmaker GlaxoSmithKline, challenging the company's patents on three of its anti-HIV medications, Reuters Health reports. AHF's original lawsuit--claiming that several of Glaxo's patents were invalid and that its prices on the medications exorbitantly exceeded the company's licensing, manufacturing, and distribution costs--was dismissed last month, but the judge allowed for the refiling of an amended complaint. The amended lawsuit, filed in U.S. district court in Los Angeles, says that because Glaxo's drugs Epivir (3TC), Retrovir (AZT), and Ziagen were partially developed with federal tax dollars, the company's exclusive patents on the medications are invalid. The suit also alleges that Glaxo has monopolized the anti-HIV drug market. Michael Weinstein, AHF president, said in a statement that the organization is appealing the lawsuit because Glaxo's high antiretroviral prices have "cost untold numbers [of] lives. Despite GlaxoSmithKline's attempts to dismiss our lawsuit as 'frivolous,' our complaint is very serious indeed." Glaxo officials called the amended lawsuit "without merit."