Any shortlist of leaders in the race to develop a coronavirus vaccine will definitely include AstraZeneca (NASDAQ:AZN). And Regeneron Pharmaceuticals (NASDAQ:REGN) will certainly rank highly on any list of the top companies developing potential treatments for COVID-19.

So far this year, Regeneron has been by far the bigger winner. The biotech stock is up more than 60%, while AstraZeneca's shares have risen 11%. But which of these coronavirus-focused stocks is the better pick going forward?

Physician wearing a mask pointing index finger up next to an image of a coronavirus

Image source: Getty Images.

The case for AstraZeneca

AstraZeneca and the University of Oxford claim one of only six COVID-19 vaccine candidates in phase 3 testing. The two partners reported positive results from a phase 1 study of their investigational vaccine AZD1222 in July. 

Assuming the phase 3 testing of AZD1222 goes well, AstraZeneca will be quite busy shipping the vaccine across the world. The company has already lined up major supply deals with the U.S., U.K., France, Germany, Japan, Argentina, Mexico, and other countries.  

But AZD1222 isn't AstraZeneca's biggest opportunity. The company's oncology drugs generate roughly 40% of total revenue. Sales for two of those drugs, Imfinzi and Lynparza, continue to soar by more than 50% year over year. AstraZeneca's top-selling product, lung cancer drug Tagrisso, isn't too far behind with sales jumping 43% in the first half of 2020.

Half of AstraZeneca's 24 late-stage programs focus on treating cancer. Several of these programs target additional indications for approved cancer drugs such as Imfinzi and Lynparza. The company also has a couple of late-stage studies featuring new candidate capivasertib.

AstraZeneca claims significant growth potential outside of oncology as well. In particular, the company appears to be in a strong position to expand its market share in the respiratory market with continued momentum for blockbuster Symbicort and two promising late-stage asthma candidates.

Because of its abundance of portfolio and pipeline riches, Wall Street analysts think that AstraZeneca will be able to deliver average annual earnings growth of 19% over the next five years. With the company's dividend yield of close to 2.5% thrown in, AstraZeneca should generate market-beating total returns.

The case for Regeneron

Regeneron experienced one setback for its COVID-19 program in July. The company and its partner Sanofi announced that a late-stage study of arthritis drug Kevzara in treating COVID-19 failed to meet primary and secondary endpoints. However, Regeneron has made significant progress with another COVID-19 program.

The big biotech is currently evaluating REGN-COV2, a two-antibody cocktail, in late-stage studies for treating and preventing COVID-19. Regeneron won a $450 million deal in July with the U.S. government to supply REGN-COV2 if it wins FDA approval or emergency use authorization.

Blockbuster eye-disease drug Eylea remains Regeneron's top-selling product. But the company's growth is being driven in large part by Dupixent, which is approved for treating asthma, atopic dermatitis (eczema), and chronic rhinosinusitis. In the first half of this year, sales for the drug nearly doubled compared to the prior-year period.

Other drugs in Regeneron's lineup are also performing well. Cancer immunotherapy Libtayo, which Regeneron co-markets with Sanofi, ranks as an especially fast-rising star. Cholesterol drug Praluent and Kevzara are generating strong sales growth as well.

Regeneron hopes to add new indications for all of its top drugs, with late-stage studies in progress. Its pipeline also includes promising new candidates, including Ebola antibody therapy REGN-EB3 and cholesterol treatment evinacumab.

Analysts expect Regeneron to increase its earnings by an average of 12% annually over the next five years. The biotech doesn't currently pay a dividend. However, Regeneron claims a big cash stockpile that it could use to reward shareholders in other ways, including potential stock buybacks and acquisitions that could fuel growth.

And the better coronavirus stock is...

Investors might want to keep both of these healthcare stocks on their radar screens. However, I think the better coronavirus stock is AstraZeneca.

My view is that AstraZeneca offers more diversification across products than Regeneron does. Its growth prospects appear to be somewhat better. The company pays an attractive dividend whereas Regeneron doesn't. It's also possible that success for AZD1222 and other COVID-19 vaccines could limit the market potential for antibody therapies such as Regeneron's REGN-COV2. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.