(Adds analyst comment, updates trading)

By Ransdell Pierson

Oct 27 (Reuters) - Bristol-Myers Squibb Co, whose high-profile Opdivo immunotherapy failed an important lung-cancer trial last summer, sharply raised its 2016 profit forecast after strong quarterly sales of other leading medicines.

The U.S. drugmaker on Thursday predicted 2016 earnings of $2.80 to $2.90 a share, up from a previous forecast of $2.55 to $2.65. It expects 2017 earnings of $2.85 to $3.05 per share.

Shares jumped 7.5 percent in afternoon trading. Despite that gain, the stock has shed about 30 percent since the unfavorable Opdivo lung cancer data was reported Aug. 5.

Sales of Opdivo, which treats melanoma and lung cancer, tripled to $920 million in the third quarter, but trailed forecasts by $27 million.

Opdivo had been considered the leader among a new class of cancer drugs called PD-1 inhibitors until August, when researchers said it failed to slow progression of symptoms in previously untreated patients with advanced lung cancer.

Earlier this month, researchers said Merck's rival Keytruda prolonged the life of similar patients; on Monday, it became the first of new immunotherapy drugs approved in the United States for initial lung cancer treatment.

Bristol-Myers authorized a new $3 billion share repurchase program, on top of $1.1 billion remaining under an authorization in 2012. It predicted flat operating expenses through 2020, which analysts said should help profit margins.

"We believe today's updates should begin to address Wall Street concerns on Bristol's near-term earnings outlook" in the wake of Opdivo's setbacks, JP Morgan analyst Chris Schott said in a research note.

Sales of Yervoy, an older melanoma treatment, jumped 19 percent to $285 million, $45 million more than expected, while sales of leukemia treatment Sprycel grew 15 percent to $472 million, $25 million above forecasts.

Eliquis, used to prevent blood clots and partnered with Pfizer Inc, jumped 90 percent to $884 million, $71 million above expectations, on compelling clinical trial data.

"We think Bristol-Myers will do very well over the long term," said Morningstar analyst Damien Conover. He expects Opdivo sales of almost $10 billion by 2020 if studies testing it in combination with Yervoy against lung cancer succeed. And he predicts Eliquis sales approaching $8 billion by 2021.

Bristol-Myers earned $1.2 billion, or 72 cents a share in the quarter, compared with $706 million, or 42 cents, a year ago. Revenue jumped 21 percent to $4.9 billion, topping forecasts of $4.79 billion.

Excluding special items, it earned 77 cents a share, well above expectations of 65 cents, according to Thomson Reuters I/B/E/S.

(Reporting by Ransdell Pierson; Editing by Bernadette Baum)