I should know, but don't know, when any patents relating to TAF were first filed. If filed more than 1 year subsequent to that publication in 2001, it seems to me that any patents relating to TAF could be subject to a number of statutory bars under 35 U.S.C. 102(b).
"In an animal study published in 2001, the company’s scientists found that TAF had 1,000-fold greater activity against HIV than [Viread]. That raised the possibility of less toxicity.
Gilead paid doctors to recruit 30 HIV patients in Los Angeles, New York, Philadelphia and Palo Alto for preliminary studies to see how it worked in humans. The trial found that TAF, the modified formulation, “had greater antiviral potency” at a fraction of the dose."
