Clinical-stage biotech companies like Moderna (NASDAQ:MRNA) and Inovio Pharmaceuticals (NASDAQ:INO) have been stealing the limelight in the coronavirus vaccine race. That may be due to their rapid entry into clinical trials and dramatic share-price gains. For example, Moderna's investigational coronavirus vaccine was the first to enter human trials, and Inovio was close behind. Moderna's shares have gained 258% this year, while Inovio has climbed 256%.

But these companies may not be closest to a win in this race. In fact, a big pharma rival might be on the brink of leaping across the finish line. I'm talking about Pfizer (NYSE:PFE), which partnered with Germany's BioNTech (NASDAQ:BNTX) in March. Why do I think Pfizer has a solid chance of winning the race? Let's take a closer look.

A medical professional vaccinates a woman in a clinical trial.

Image source: Getty Images.

First, a little background. Like Moderna, the Pfizer/BioNTech team is developing a messenger RNA (mRNA) vaccine. Traditional vaccines introduce weakened virus into the body to stimulate immunity. The Pfizer candidate instead uses mRNA to instruct the body's cells to produce proteins that will prevent infection.

Promise in key areas

Results from a phase 1 trial of the Pfizer candidate show promise in key areas. The first: neutralizing antibodies. These are important because their role is to block infection. In the trial, neutralizing antibody levels in younger volunteers -- those ages 18 through 55 -- were 3.8 times those found in recovered coronavirus patients.

Now here's the second key area: vaccine performance in older patients. Safety and efficacy in this group are essential since the elderly have been among the most vulnerable during this outbreak. Trial results showed that in participants ages 65 through 85, neutralizing antibodies were 1.6 times the level found in recovered coronavirus patients.

The vaccine candidate also scored a win on safety, with light-to-moderate fever noted in just under 20% of trial volunteers.

Pfizer recently proposed an expansion of its phase 3 trial to the U.S. Food and Drug Administration (FDA). The trial would include 44,000 participants instead of 30,000 as originally planned. The expansion is meant to include a wider range of volunteers, such as those with chronic, stable HIV, or hepatitis. This is positive, as it would offer data on populations with pre-existing conditions. They, too, have been vulnerable during the outbreak.

1.3 billion doses

As for manufacturing, big pharma rival AstraZeneca (NYSE:AZN) is a leader. The company's supply agreements bring its capacity to nearly 3 billion doses. Still, Pfizer is prepared to deliver as many as 1.3 billion doses by the end of next year and has signed supply agreements with the U.S., Europe, and others. And Pfizer's capacity remains greater than that of Moderna, its closest biotech rival in terms of timeline. Moderna aims to deliver between 500 million and 1 billion doses annually starting next year.

All of this looks good and supports my view of Pfizer as a possible winner at this point in the race. But what makes the big pharma company stand out has to do with the timing of clinical-trial results. Pfizer expects a "conclusive readout" on the vaccine candidate's efficacy by the end of October. In fact, the company has even said a regulatory submission by the end of the month is a possibility.

In a "normal" situation, regulatory submission prior to the conclusion of a phase 3 study would seem impossible. But FDA Commissioner Stephen Hahn recently said the agency would consider emergency use authorization (EUA) for coronavirus vaccine candidates prior to phase 3 completion. This would allow a vaccine to enter the market while researchers compile final results to support a possible approval.

Data readouts

Rivals have been less specific when speaking about data readouts. For instance, AstraZeneca said it expects late-stage study results "later this year." And Moderna recently said results to support an EUA may be available by late November. 

So, considering the elements above, we can say Pfizer may win this vaccine race -- if current trials continue smoothly and results are positive. Anything can happen in a clinical trial -- even during the final stages. That's an important point to keep in mind when investing in biotech and pharmaceutical stocks.

And here's where Pfizer offers another advantage beyond its position in the coronavirus vaccine race. With its vast product portfolio and 89 pipeline projects, Pfizer's long-term revenue prospects won't depend on the outcome of its coronavirus program. So, coronavirus vaccine victory or not, Pfizer stock may be a long-term winner in investors' portfolios.