Gilead Sciences (NSDQ: GILD) has announced that it has identified tampered and counterfeit versions of its HIV drugs Biktarvy and Descovy in the U.S. supply chain. Biktarvy is a blockbuster drug cocktail, raking up $7.26 billion in sales last year. 2020 sales of Descovy were $478 million. Foster City, Calif.–based Gilead said that unauthorized distributors…