Bristol-Myers Squibb reported better-than-expected first-quarter revenue on Thursday and raised its full-year forecast due to growth from its portfolio of drugs that spur a patient's own immune system to fight cancer.

U.S.-listed shares of the company rose 1.4% in premarket trading.

The company's shares have dropped more than 20% over the past month as investor concerns about U.S. President Donald Trump's tariff threats have roiled the markets.

Chief Financial Officer David Elkins said in an interview that the company's global manufacturing footprint puts it in a good position to deal with whatever tariffs may come.

"We have a really resilient supply chain, and we have manufacturing globally," Elkins said. "That gives us a lot of flexibility to move our manufacturing as appropriate."

The U.S. started a probe into the pharmaceutical sector earlier this month as part of a bid to impose tariffs on the industry.

Elkins said it was too early to understand the impact of potential tariffs targeting the pharmaceutical industry, and that Bristol Myers' forecast did not include any assumptions related to them.

Revenue in the quarter fell less sharply than Wall Street analysts had forecast, coming in at $11.2 billion for the quarter, down from $11.9 billion a year earlier. Analysts had expected revenue of around $10.6 billion, according to LSEG data.

Sales of the company's cancer immunotherapy Opdivo were $2.3 billion in the quarter, compared with Wall Street forecasts of just under $2 billion. Sales of its older immunotherapy, Yervoy, were $624 million in the quarter, more than $100 million higher than analysts' forecasts.

The U.S. drugmaker also benefited as sales of some of its older or off-patent drugs like blood thinner Eliquis, which it shares with Pfizer PFE.N, and blood cancer drug Revlimid fell less than expected.

The company posted earnings of $2.5 billion, or $1.20 a share, roughly in line with Wall Street expectations.

It raised its full-year forecast for revenue to a range of $45.8 billion to $46.8 billion from its previous forecast of $45.5 billion.

It now expects full-year earnings in the range of $6.70 to $7 a share.