Editor’s note: This story has been updated to reflect new information about the availability of the generic product and removes incorrect information from an FDA official about when this generic drug would be made available in the U.S.

The blockbuster announcement — long thought to be expected sometime in 2021 — took advocates for the HIV community by surprise: the Food and Drug Administration on Friday approved a generic version of Gilead Science’s antiretroviral tenofovir disoproxil fumarate/emtricitabine — commonly known as Truvada.

However, Gilead issued a statement late Friday that cast doubt on just how soon this generic combination treatment may be available to consumers, as Poz reported. The bottom line: don’t hold your breath.

“A generic version of Truvada will not be immediately available,” reads the statement. “It’s important to note that there are a number of factors involved in commercialization that are not tied directly to FDA approval.”

“It’s not uncommon in patent settlement agreements for generics to negotiate language permitting full approvals months and years in advance of the settlement license date,” Tim Horn, deputy executive director of HIV and HCV programs at Treatment Action Group, told Poz. “Regardless, now is the time to start thinking seriously about the advantages, as well as the drawbacks, of generic products to prevent and treat HIV.”

As Poz reported, Gilead’s patent for the tenofovir disoproxil fumarate component of Truvada expires next month. But exclusive rights for development and sale of the drug for pediatric use stays with the California-based company until next January. In most cases, according to the report, manufacturers of generic products often hold onto exclusive rights for a determined period before competitors are permitted to produce their own versions, which in turn drive down prices.

And according to Gilead, its patent for the other medication in Truvada, emtricitabine, does not expire until 2021.

Poz reported the company chosen by the FDA the right to produce generic Truvada is Teva Pharmaceuticals. A spokesperson for Teva confirmed the company received approval, but had nothing to add.

HIV activist James Krellenstein is credited with finding the FDA document dated June 5th, which shows the agency added Truvada to the agency’s list of medications that have been granted “paragraph IV patent certification.”

That certification for Truvada indicates that Teva applied for an abbreviated new drug application, otherwise known as ANDA, according to Martin Shimer, RPh, deputy director of the Office of Generic Drug Policy at the FDA. What that means is that Teva is challenging Gilead’s patent on the combination tablet and seeking the rights to produce a generic equivalent.

This certification doesn’t necessarily mean Truvada’s patent has been invalidated by the FDA. But as Poz reported, that could happen.

Still, the timing of the generic’s availability remains the big question.

“FDA’s ability to approve an ANDA,” said Shimer, “often does not result in immediate marketing by the ANDA applicant that just gained approval.”

One possible scenario, he told Poz, would be for Teva and Gilead to reach a legal compromise that details the near-term availability of generic Truvada. That is not something the FDA is typically made aware of, according to Shimer.

The fixed-dose combination tablet, like its brand-name version, is to be used as a component of an HIV treatment regimen and as pre-exposure prophylaxis or PrEP. The only difference between the generic and Truvada will be the cost and reportedly a variation on its famous powder-blue color.

“While this is stunning news that AIDS activists didn’t expect until 2021, I’m worried about the fallout,” ACT UP and Treatment Action Group veteran Peter Staley told Poz. “Gilead’s patient and copay assistance programs have become central pillars in patient access. They must maintain these programs, and Teva must establish equivalent or better assistance programs for their generic version.”