Shares of AstraZeneca (AZN -0.84%) have jumped more than 10% this week. On Monday, the British drugmaker reported positive results from a clinical study of Enhertu in treating HER2-positive early breast cancer. However, the main reason for AstraZeneca's big gain was Pfizer's (PFE -0.50%) announcement of a deal with the Trump administration.
Pfizer CEO Albert Bourla appeared with President Donald Trump at a press conference on Tuesday to announce the landmark agreement. Pfizer plans to slash the prices on many of its prescription drugs in the U.S. and invest $70 billion in expanding its domestic operations. It will also participate in a new TrumpRx website that will help consumers find medications at discounted prices.
In return, Pfizer will enjoy a three-year grace period during which it won't be affected by the Trump administration's tariffs on pharmaceutical imports to the U.S.
Why AstraZeneca could benefit, too
Good news for Pfizer could be good news for AstraZeneca, for two reasons.
First, President Trump hinted in the press conference earlier this week that other deals similar to Pfizer's could be on the way. As the fourth-largest pharmaceutical company based on market cap, AstraZeneca is likely to be among the drugmakers lining up to follow in Pfizer's footsteps.
Second, like Pfizer, AstraZeneca already has plans to expand in the U.S. CEO Pascal Soriot said in the company's 2025 first-half update, "As we enter our next phase of growth, we have pledged $50 billion to continue to grow in the U.S., which includes the largest manufacturing investment in AstraZeneca's history, set for Virginia."
The bottom line is that the chances seem to be pretty good that his company will be able to secure an exemption from tariffs over the next three years, as Pfizer has.

Image source: Getty Images.
Is AstraZeneca stock a buy?
Some of the uncertainty that was hovering over the entire biopharmaceutical industry, including AstraZeneca, has now been lifted. Is the stock a buy? Maybe so.
For one thing, it is priced reasonably with a forward price-to-earnings ratio of around 15, and it continues to deliver strong earnings growth. The company is also making great strides with its pipeline, announcing more than a dozen positive results from late-stage clinical studies in recent months.
I think AstraZeneca should be able to deliver solid gains for long-term investors. It's not the best pharma stock on the market, in my view, but it's still a pretty good one.