FOSTER CITY, Calif. ( TheStreet) -- Gilead Sciences ( GILD) reported disappointing second quarter earnings impacted by lower-than-expected sales of the company's key HIV drugs. The company lowered product sales guidance for 2010. Gilead reported net income of $712.1 million, or 79 cents a share, up from $571 million, or 61 cents a share in the year-ago quarter. On an adjusted basis, Gilead earned 85 cents a share in the June quarter, two cents below the consensus analyst estimate of 87 cents a share, according to Thomson Reuters. Total revenue in the quarter came in at $1.93 billion, up 17% from one year ago but lower than the $1.96 billion Wall Street forecast. Moving forward, Gilead said total product sales for 2010 would be in the range of $7.3 billion to $7.4 billion, a small drop from the previous guidance range of $7.4 billion to $7.5 billion. Gilead's business is dominated by sales of drugs used to treat patients with HIV and other viral-based diseases. Total antiviral sales (which includes HIV and hepatitis B) rose 13% to $1.69 billion in the quarter. But sales of two important HIV drugs fell below Wall Street forecasts. Atripla, a once-daily pill that combines three different HIV medicines including one from Bristol-Myers Squibb, recorded second-quarter sales of $715.8 million, below the consensus estimate of $726 million. Likewise Truvada sales of $641.7 million in the quarter fell below the $674 million expected by the Street. At an AIDS research meeting in Austria this week, Gilead is presenting late-stage data on a new single-pill HIV treatment nicknamed Btripla which combines Truvada with an experimental drug from Johnson & Johnson ( JNJ) known as TMC278. Gilead hopes Btripla can boost the company's profits and stave off generic competition to its HIV drug franchise, although investors haven't necessarily bought into that strategy. Ahead of its earnings announcement, Gilead shares closed Tuesday up fractionally to $33. The stock was down 4.5% to $31.57 in the after-hours trading session. -- Reported by Adam Feuerstein in Boston. Follow Adam Feuerstein on Twitter.