(Adds Revlimid background, analyst comment)

July 28 (Reuters) - U.S. biotechnology company Celgene Corp raised its adjusted earnings forecast for 2016 and posted a better-than-expected quarterly profit due to higher demand for its blockbuster cancer drug, Revlimid.

Revlimid's sales jumped about 18 percent to $1.70 billion, above the consensus estimate of $1.66 billion compiled by RBC Capital Markets.

The drugmaker has been working on expanding Revlimid's use and geographical reach, but earlier this week, data showed the drug failed to extend survival as a maintenance therapy for a type of blood cancer after patients had responded to prior treatment.

The drug, which generates annual sales of about $6 billion and accounted for about 62 percent of net product sales in the second quarter, will continue being tested for use in a variety of lymphomas.

However, Celgene on Thursday nudged up its full-year sales forecast for Revlimid to $6.8 billion from $6.7 billion.

It also raised its adjusted earnings forecast for 2016 to a range of $5.70-$5.75 per share, from $5.60-$5.70.

Excluding items, Summit, New Jersey-based Celgene earned $1.44 per share in the second quarter, topping the average analyst estimate of $1.38, according to Thomson Reuters I/B/E/S.

"Strong performance of core products in-line or better than expectations, continued good operating leverage, and share buybacks prompt a beat-and-raise 2Q for CELG," Jefferies analyst Brian Abrahams said in a note.

Celgene purchased about 3.4 million of its shares for about $343 million in the quarter.

The company's total revenue, which includes net product sales and other revenue, rose about 21 percent to $2.75 billion in the quarter ended June 30, roughly in line with Wall Street estimate of $2.7 billion.

Celgene's net income rose to $598.2 million, or 75 cents per share, from $356.2 million, or 43 cents per share, a year earlier.

(Reporting by Natalie Grover in Bengaluru; Editing by Maju Samuel)