A U.K. court ruled against a patent extension filed by Gilead Sciences, the manufacturer of the highly effective HIV prevention drug Truvada, which will open the U.K. market to a generic version of the pill.

This week's ruling follows another European defeat for the pharmaceutical giant. Last year, Irish courts also ruled against Gilead's attempt to maintain an exclusive patent to produce Truvada. Across the world, Gilead has gone to court to extend and defend its patents, often fighting generics manufacturers Mylan and Teva. Increasingly, Gilead has been losing these cases across Europe.

In a statement sent to NBC News on Friday, a Gilead spokesperson said the company is "disappointed in the High Court of England and Wales' decision and intends to appeal."

In the U.S, Gilead is still the sole manufacturer of Truvada for HIV prevention, or PrEP (pre-exposure prophylaxis), and it costs about $2,000 for a month’s supply. The CDC recently estimated that only "a small percentage" of Americans who could benefit from PrEP are taking it. A new activist effort called #BreakThePatent is fighting the company's exclusive right to sell Truvada in the U.S., hoping the move will lower the treatment's cost and increase its availability.

HIV advocates applauded Wednesday's court decision, believing a new, cheaper drug would lead the U.K. government to finally approve the HIV-prevention treatment to be included as a free service across the U.K.'s National Health Services.

“I think that this [ruling] is arguably a kind of game changing-moment in terms of getting PrEP to be available," said Liam Beattie, campaigns officer at the Terrence Higgins Trust, the U.K.’s largest HIV and sexual health charity.

Deborah Gold, CEO of U.K.-based National Aids Trust, also welcomed this week's court ruling, saying a generic version of Truvada will be “a fraction of the cost." She lamented that "some have acquired HIV after being turned away from clinics" that were providing the preventive pill.

Gold and Beattie both called on the U.K. government to provide PrEP by next April. "That’s doable," Beattie said. "And given what the court ruling said, we think it’s more doable now.”

On Thursday, both Conservative and Labour members of parliament called for the U.K. government to speed its delivery of PrEP to all who need it. According to BBC News, Labour MP Stephen Doughty called PrEP a "life-saver for individuals, and a cost-saver for the NHS."

Those in favor of the ruling against Gilead hope the U.K. will see results similar to those seen in Ireland, where generic PrEP became available in December 2017 following a court ruling against Gilead.

"We have seen the monthly price drop from €400 to between €90 to €110 per month. We have also seen wider availability of PrEP," Niall Mulligan, executive director of HIV Ireland, told NBC News in an email. "The Irish Minister of Health, Mr. Simon Harris, has made a commitment to have an official PrEP Programme in place in early 2019."

In the U.S., the patent for Truvada as PrEP expired last year, and the FDA approved a generic version produced by Teva Pharmaceuticals. However, HIV activists have alleged that a confidential agreement between Teva and Gilead is preventing a generic from coming to market. They've accused Gilead and Teva of engaging in “pay for delay” — the controversial technique being investigated by the Federal Trade Commission in which the brand name manufacturer and the generic manufacturer confidentially agree about when to introduce a generic.

“This ruling provides further evidence that Gilead’s Truvada patents are weak,” Peter Staley, co-founder of PrEP4All, a group advocating for a national PrEP access program in the U.S., said of the U.K. court decision. “Prevention activists in the U.S. are exploring multiple avenues for challenging those patents here, and we are increasingly confident we can win.” Staley and his PrEP4All coalition have pushed Gilead on its alleged “pay for delay” deals.

Gilead’s most recent courtroom failure adds to growing calls to reduce the price of the drug, which in the U.S. has increased in price every year since it was released. When Truvada was approved for HIV prevention in 2012, it cost about $1,200 per month. Now, it costs roughly $2,000 per month.

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