In case you haven't noticed, antibody therapies are all the rage when it comes to developing potential treatments for COVID-19. Two companies in the thick of the race with experimental novel-coronavirus antibody therapies are Sorrento Therapeutics (NASDAQ:SRNE) and Regeneron Pharmaceuticals (NASDAQ:REGN).

Both biotech stocks have been big winners so far in 2020. Sorrento's shares have skyrocketed more than 50%, while Regeneron is up more than 40%. Which of these coronavirus-focused stocks is the better pick for long-term investors?

Gloved hand separating fallen wooden dominoes spelling out COVID19 from a set of standing dominoes

Image source: Getty Images.

The case for Sorrento Therapeutics

Two potential COVID-19 cures waiting in the wings? That's how Sorrento Therapeutics CEO Henry Ji might put it. After Sorrento first announced in May that it had identified an antibody that could completely neutralize SARS-CoV-2, Ji went on TV saying that his company could be on track to have a cure for COVID-19.

Earlier this month, Sorrento reported that another antibody, discovered in March, also demonstrated the ability to completely inhibit the novel coronavirus. These two antibodies that could potentially serve as antidotes to COVID-19 aren't the only coronavirus programs that Sorrento is working on, though.

The company recently submitted an application to the Food and Drug Administration for Emergency Use Authorization for its COVI-TRACK in vitro diagnostic test for detecting COVID-19 antibodies. It's collaborating with Mount Sinai Health System in New York City to develop COVID-19 antibody cocktail therapies. Sorrento also launched an effort to develop a COVID-19 vaccine.

None of Sorrento's COVID-19 antibody therapy or vaccine candidates have advanced beyond preclinical testing yet. However, the biotech's pipeline includes five clinical-stage programs that aren't related to the coronavirus. Its lead candidate, resiniferatoxin (RTX), is being evaluated in phase 2 clinical studies for treating the pain of terminal cancer and pain associated with osteoarthritis. Sorrento also has three cancer immunotherapies in early-stage development.

The biggest argument for buying Sorrento shares is that pretty much any success would likely be a major catalyst. Sorrento's market cap is currently around $1 billion. All it would take for the biotech to take off would be some positive news from planned clinical testing of its COVID-19 programs.

The case for Regeneron

Regeneron is mounting a fight against COVID-19 on two fronts. The company and its partner Sanofi are evaluating rheumatoid arthritis drug Kevzara in a phase 2/3 study for treating patients with respiratory illness caused by COVID-19. After a review by the study's Independent Data Monitoring Committee in late April, the trial refocused only on more critical patients.

Last week, Regeneron began a phase 1 clinical study evaluating an antibody cocktail for both preventing and treating COVID-19. The biotech thinks that this antibody cocktail could be available much sooner than a vaccine, and treat patients already diagnosed with the novel coronavirus disease. It also anticipates that the cocktail could be helpful for elderly and immunocompromised patients who don't respond well to COVID-19 vaccines.

Unlike Sorrento, Regeneron doesn't need its COVID-19 programs to go well to be successful. The company raked in $1.83 billion in sales in the first quarter of 2020, up 33% year over year. It's already quite profitable, with earnings soaring 36% year over year in Q1 to $625 million.

Regeneron claims multiple big winners in its lineup. Sales continue to climb for blockbuster eye-disease drug Eylea. Momentum is picking up strongly for immunology drug Dupixent. Recent positive clinical results for Libtayo could lead to expanded indications for the immunotherapy, as a first-line treatment for non-small cell lung cancer and as a second-line treatment for advanced basal cell carcinoma.

Meanwhile, Regeneron's pipeline is loaded with candidates that could pave the way for future growth. The company has eight late-stage programs, 12 phase 2 programs, and 10 phase 1 programs (including its COVID-19 antibody cocktail).

The better coronavirus stock

You've probably heard the old expression that "a bird in the hand is worth two in the bush." I think that adage applies to the choice between Sorrento and Regeneron.

Sorrento has some intriguing candidates, but they're all early in development. Regeneron has several successful drugs already on the market, plus a deep pipeline. Sorrento could potentially become a big winner; Regeneron already is a big winner. And with its antibody cocktail already in clinical testing, it has a big head start over Sorrento on the COVID-19 front.

Regeneron is the better coronavirus stock. It's the better stock, period.

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.