A researcher in a Bristol-Myers Squibb laboratory. The drugs — ipilimumab (brand name Yervoy) and nivolumab (Opdivo) — belong to a class called checkpoint inhibitors and are made by Bristol-Myers Squibb.

Bristol-Myers Squibb said Thursday said it has voluntarily withdrawn its FDA application seeking approval for a drug combination to treat advanced lung cancer.

The New York-based pharmaceutical giant said it pulled its applications for a combination of its immunotherapy drugs Opdivo and Yervoy after recent discussions with the Food and Drug Administration.

Bristol, which announced a planned $74 billion acquisition of cancer drug maker Celgene earlier this month, is still pursuing approval for the combination for use by lung cancer patients with a different biomarker. Such usage is being tested in a separate part of the study.

Sales of Bristol's blockbuster drug Opdivo, which boosts the immune system to attack cancer, has fallen behind its leading competitor, Merck's Keytruda.

In two highly anticipated clinical trials presented in April, Keytruda edged out Opdivo in reducing the risk of death from advanced lung cancer when combined with chemotherapy. Keytruda's sales surpassed Opdivo's in the second quarter of last year and widened the gap even more in the third quarter.

Earlier this month, some analysts and investors suggested that one reason Bristol may have launched its bid for Celgene — the biggest pharmaceutical deal ever — was over concerns about Opdivo's ability to compete in the all-important lung cancer market.

The announcement came as the company posted better-than-expected fourth-quarter earnings, and forecast 2019 earnings roughly in line with Wall Street expectations.

The company reported earnings of 94 cents per share, 9 cents above estimates. Revenue of $5.97 billion was in line with analyst estimates.

Bristol forecast adjusted earnings of $4.10 to $4.20 per share, excluding any impact from the Celgene deal.

Its stock was slightly higher Thursday morning.

—Reuters contributed to this report.