Nov 7 (Reuters) - Drugmaker Gilead Sciences on Tuesday said third-quarter sales were little changed from a year earlier, but earnings rose 21% due mainly to lower taxes.

The Foster City, California-based company reported a quarterly profit of $2.29 per share excluding items, on total revenue of $7.1 billion, up from $1.90 a share on revenue of just over $7 billion in the year-ago quarter.

Wall Street analysts had expected an adjusted profit of $1.92 per share on revenue of $6.8 billion, according to LSEG data.

Sales of HIV drug Biktarvy rose 12% to $3.1 billion, which was in line with analysts' estimates. Sales of COVID drug Veklury fell 31% to $636 million, but still came in well above Wall Street expectations of $363 million.

Oncology sales rose 33% to $769 million.

"We are seeing strong growth in our core base business, driven by Biktarvy in HIV and Trodelvy in cancer," Gilead CEO Daniel O'Day said in an interview.

He noted that Gilead will be announcing results from several pivotal-stage clinical trials next year, including Trodelvy as a first-line treatment for lung cancer and oral antiviral obeldesivir as a treatment for COVID.

Gilead said its effective tax rate for the third quarter dropped to 6.3% from 26.6% for the same period in 2022, primarily due to a decrease in tax reserves related to a settlement with the U.S. Internal Revenue Service for prior tax years.

For 2024, Gilead said it continues to expect a tax rate of 16% percent.

Gilead raised its full-year forecast for adjusted earnings and now expects $6.65 to $6.85 per share, up from $6.45 to $6.80. The company also increased its 2023 revenue estimate to a range of $26.7 billion to $26.9 billion from a previous forecast of $26.3 billion to $26.7 billion. (Reporting By Deena Beasley Editing by Bill Berkrot)