Moderna (NASDAQ:MRNA) and Gilead Sciences (NASDAQ:GILD) may have gotten your attention in recent weeks if you've been following coronavirus stocks. Moderna was the first to enter human trials with its investigational vaccine. Gilead's big moment came when the U.S. Food and Drug Administration granted its investigational treatment, remdesivir, emergency use authorization. So, we can say both companies are leaders in the coronavirus space.

But there's more to these biotech players than their coronavirus programs. Both have full pipelines, and Gilead has a portfolio of commercialized products as well. Which is a better buy today? Let's take a closer look.

A doctor looks at a COVID-19 vial

Image Source: Getty Images

The case for Moderna

It's not an exaggeration to say Moderna has taken center stage due to the speed of its coronavirus vaccine development. Last month, the company announced positive interim results from its phase 1 trial. Information on neutralizing antibodies -- or those that block infection -- was only available for eight people. But in all eight, neutralizing antibodies were at or above levels of those of recovered coronavirus patients.

Now, it will be important to see if that holds true for the rest of the volunteers in the phase 1 trial and for the 600 people Moderna hopes to enroll in the phase 2 study. The company is currently dosing volunteers in that trial, which will examine the safety, immune response, and potential adverse effects in two groups -- age 18 to 55, and 55 and older. Moderna plans to begin a phase 3 study in 30,000 people next month.

Like rivals, Moderna is aiming to meet the U.S. government's Operation Warp Speed goal of delivering a vaccine to Americans by January. So, it's clear that any vaccine development news from now to then will be a catalyst for the share price. Moderna said it's on track to deliver from 500 million to possibly 1 billion doses of vaccine a year as of next year.

Beyond the coronavirus, Moderna is using its messenger RNA (mRNA) technology across its pipeline of more than 20 candidates addressing infectious diseases, cancer, autoimmune disorders, and other illnesses. Moderna harnesses the power of mRNA to instruct the body's cells to produce proteins to fight or prevent disease. Potential success in coronavirus may prove this method works in humans -- and that would be a positive sign for the rest of the pipeline.

The case for Gilead

Gilead may soon set pricing and start selling remdesivir for the treatment of coronavirus. The company promised to donate its existing supply, which totals about 1.5 million individual doses. That supply is expected to run out this month or in early July, Fierce Pharma reported, citing SVB Leerink analyst Geoffrey Porges. Gilead's Chief Financial Officer Andrew Dickinson told Porges that remdesivir sales may start in the second half of 2020, and he expects the product to be a multi-year opportunity.

Pricing will be a key point, as Gilead is prepared to invest as much as $1 billion in remdesivir this year. The company faces the challenge of setting a price that will satisfy investors and be affordable for patients.

The latest phase 3 trial data may lead to more demand for the treatment. Patients taking remdesivir for five days were 65% more likely to show clinical improvement on day 11 than those in a standard of care group. A separate National Institute of Allergy and Infectious Diseases study showed remdesivir led to more rapid recovery and early treatment produced better outcomes.

While everyone has been talking about Gilead's coronavirus program, we shouldn't forget the rest of what the company has to offer. Gilead has nearly 50 drug candidates in the pipeline and almost 30 commercialized products in areas including HIV, oncology, and cardiovascular disease. Gilead's HIV business is particularly attractive. Biktarvy, approved in 2018, is the No. 1 prescribed treatment regimen for HIV patients in the U.S. today. Sales of the drug more than doubled to nearly $1.7 billion in the first quarter compared with the year earlier period. And Gilead's HIV portfolio as a whole posted a 14% increase in sales for the quarter.

Moderna or Gilead?

As investors cheered on the progress of companies working on coronavirus treatment and prevention, Moderna stock soared 208% this year, while Gilead advanced 12%.

Moderna's market value has soared to $22 billion from less than $8 billion at the start of January. At that level, this clinical stage biotech is valued more than some companies with marketed products. Still, with more coronavirus vaccine trial data on the horizon, if the news is good, the shares surely will head higher. Moderna shares still have 44% to gain to reach Wall Street's average price estimate.

Gilead has also seen its market value grow -- to $91 billion from a little more than $80 billion -- but Gilead boasts a full portfolio of revenue-generating products. If remdesivir sales don't meet expectations, other drugs may compensate.

In the coronavirus race, vaccine development is generating the most excitement, so it is likely Moderna's gains will surpass those of Gilead in the near term. But in the long term, I favor Gilead for the strength of this biotech company's entire portfolio.

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.