Drug stocks are tumbling as investors worry about how the coronavirus outbreak may impact their operations. The pandemic, which is halting a great part of the world economy, may also slow clinical trials, drug development, and drug manufacturing. In spite of these near-term -- and temporary -- disruptions, the following three pharma stocks are bargains today considering future revenue prospects.

Pills spill out of a bottle on a counter.

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1. Sanofi

Sanofi (NASDAQ:SNY) has been making headlines for its work on coronavirus treatment and prevention. While any success there would be a plus, my attention is on products with more potential for long-term growth. Sanofi must find ways to compensate for declines in older blockbuster drugs. Diabetes drug Lantus is a good example. The drug used to generate $7 billion annually, but competition from biosimilars and other new drugs has halved that figure.

New CEO Paul Hudson's strategy involves a shift into higher growth areas. He ended Sanofi's diabetes and cardiovascular research, and in January, Sanofi completed the acquisition of immuno-oncology company Synthorx. The French drugmaker also is betting on eczema drug Dupixent, and in the latest earnings report said the drug is on its way to the goal of generating peak sales of $11 billion. In the fourth quarter, Dupixent sales surged 135% and annual sales soared 152% to $2.3 billion. Sanofi shares are down 18% so far this year, offering a decent entry point to bet on the company's transformation.

2. Novartis

What I like most about Novartis (NYSE:NVS) right now is the fact that it started the year with more newly approved drugs than any other big pharma company. The Food and Drug Administration approved five new Novartis drugs last year, and Novartis says each has blockbuster potential.

One of these new additions is Piqray, the first FDA-approved treatment for people with a PIK3CA gene mutation in HR+/HER2- advanced breast cancer. A DelveInsight report shows the market size for this cancer type in major global markets was $5.2 billion in 2017 and will grow at a 0.8% compound annual growth rate through 2028. So far, Piqray generated $43 million in its first quarter on the market and $67 million in the quarter that followed.

In the most recent earnings call, Novartis said it has 15 major launches spanning the next three years. That equals many more opportunities to compensate for declining sales of former blockbusters, like cancer drug Gleevec, that have been hurt by generic competition. Novartis' stock has slipped 19% this year, trading near its lowest level in relation to earnings in about a year.

3. Bristol Myers Squibb

Bristol Myers Squibb's (NYSE:BMY) acquisition of Celgene last year adds more earnings potential to a company that already has surpassed analysts' earnings per share estimates for the past four quarters. At the time of the acquisition announcement, Bristol Myers Squibb said the deal represented more than $15 billion in potential revenue, with six product launches in the near term.

This week, the FDA approved a drug Bristol Myers Squibb acquired as part of the Celgene deal. Ozanimod, to be commercialized under the name Zeposia, is a potential blockbuster for the treatment of multiple sclerosis. Celgene originally predicted peak annual sales of $4 billion to $6 billion for the drug. Usually, pharmaceutical companies launch newly approved products as soon as possible, but considering the coronavirus outbreak, Bristol Myers Squibb said it will delay the launch of Zeposia. The company said it would continue to "monitor the environment" before determining when to begin marketing the drug. This represents a short-term hurdle as it delays revenue, but the long-term impact should be limited. Zeposia is currently under review in Europe, and an approval decision is expected in the first half of this year.

Bristol Myers Squibb shares are down 23% this year, trading near their lowest ever in relation to book value, offering an attractive entry point to this pharmaceutical stock