Inovio Pharmaceuticals (NASDAQ:INO) and Regeneron Pharmaceuticals (NASDAQ:REGN) are both deeply involved in making medicines to fight against COVID-19, but the similarities end there. Inovio is a clinical-stage biotech, hoping to utilize its DNA-based vaccine technology to produce an effective inoculation for the coronavirus that will cement the company's long-term survival. In contrast, Regeneron is older, larger, and more established, boasting consistent profitability and a bevy of antibody therapies. Whereas a successful coronavirus program could be revolutionary for Inovio's stock, Regeneron's antibody therapy for COVID-19 may not fundamentally change the company's ability to successfully compete, even if it provides a new source of revenue.

Both stocks have strongly outperformed the market this year, but their future growth prospects are quite different in terms of their level of risk, and they appeal to different types of investors as a result. In my view, Inovio is the preferable stock for investors with a very high tolerance for risk, whereas Regeneron is a better option for most people, especially those who are content with steady long-term growth. Let's take a look at each company to understand this dichotomy a bit more.

A stock chart with superimposed coronavirus particles.

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When will Inovio's coronavirus vaccine advance in trials?

Inovio's coronavirus vaccine has successfully finished its phase 1 clinical trials. Due to a regulatory hold by the U.S. Food and Drug Administration (FDA), the company can't proceed to the next phases for the time being. This hold may lift before the end of the year, but in the meantime it's clear that Inovio isn't about to be the first company to successfully make a coronavirus vaccine.

Once Inovio gets its coronavirus trial rolling again, the company's stock might grow rapidly, if the first half of the year is any indication. Until then, though, there isn't much for investors to look forward to. Inovio has no products on the market, and it isn't profitable, with no recurring revenue to speak of. While Inovio has several other vaccines for diseases including HIV and Ebola in its development pipeline, the coronavirus vaccine is clearly where the majority of the market's attention will be. In terms of its most advanced pipeline programs, Inovio's vaccine against precancerous cervical dysplasia is in phase 3, making it the closest to completion.

There's no guarantee that any of Inovio's ongoing programs will ever pan out in the form of earnings, which makes it a risky stock. On the other hand, headline-driven vaccine speculation could readily make shareholders rich. If you're comfortable with the idea of wild volatility and potentially multiple-fold growth that tracks sentiment about its vaccine, Inovio might be right up your alley.

Regeneron's antibody therapy makes a strong impression

Unlike Inovio, Regeneron is a good bet for investors who aren't comfortable with taking on large amounts of downside risk. Regeneron has a special expertise in developing therapeutic antibodies, of which it has seven on the market. One of Regeneron's medicines, Inmazeb, is approved for treating Ebola infections, whereas its Libtayo product treats metastatic cutaneous squamous cell carcinoma, a form of skin cancer. Thanks to this portfolio of products, Regeneron has a profit margin of 34% and $8.7 billion in trailing revenue. Year over year, its quarterly revenue expanded by 23.7%, whereas its quarterly earnings growth was an impressive 364.7%. It also has a substantial drug development pipeline that includes a balanced mixture of late- and early-stage therapeutics.

Its antibody therapy for COVID-19, REGN-COV2, is the company's primary program in development for the coronavirus market. Right now, Regeneron is investigating it in three separate clinical trials for applications ranging from preventing infection to saving patients who are hospitalized. Two of these programs are in their later stages. It also has a phase 3 program examining whether its antibody sarilumab could be useful for coronavirus patients in critical condition. Given the current level of need and its pace of development, it's possible that Regeneron could get emergency authorization for use as early as the end of this year.

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Overall, Regeneron's fortunes are not riding on the success of any single project in the way that Inovio's are. What's more, the company's recurring revenues and profitability will continue to deliver sustainable equity growth. While it may not have the chance for a rapid, massive price spike from vaccine speculation like Inovio does, it is also likely to be far more resilient in the face of bad news. Thus, Regeneron's demonstrated history of success makes it a far more appealing stock in the long term. Meanwhile, Inovio could still pull through with its vaccine, so investors should carefully consider whether the exposure to risk is worth the potential upside.

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.