(In first sentence corrects to say Gilead forecast a further slowdown in the current year, not next year. In 3rd paragaph, corrects to say the $1.78 per share is excluding one-time items, not after one-time items)
By Deena Beasley
Feb 6 (Reuters) - Gilead Sciences Inc on Tuesday said fourth-quarter sales of its flagship hepatitis C drugs fell by more than half amid increased competition and forecast a further slowdown in the current year, sending its shares lower after the closing bell.
For full-year 2018, the biotechnology company forecast product sales of $20 billion to $21 billion, down from $25.7 billion last year. The company also projected a 2018 tax rate of 21 percent to 23 percent.
Gilead, which last year paid nearly $12 billion for cancer immunotherapy company Kite Pharma, said it earned $1.78 a share in the fourth quarter excluding one-time items. Wall Street analysts, on average, had forecast $1.67 a share, according to Thomson Reuters I/B/E/S.
Including a $6 billion income tax charge related to U.S. corporate tax changes, the company posted a fourth-quarter net loss of $3.87 billion.
Quarterly sales of hepatitis C drugs totaled $1.5 billion, down from $3.2 billion a year earlier, but in line with analysts' forecasts. The company's antiviral and HIV drug sales rose to $3.7 billion from $3.4 billion.
Shares of Gilead, which rose 2.5 percent to close at $80.38 in regular trading on the Nasdaq, were down 3 percent at $78 after hours. (Reporting by Deena Beasley, editing by G Crosse)