Moderna's (MRNA -1.52%) third-quarter earnings report on Thursday is sure to be chock-full of exciting numbers and news. Investors are expecting another billion-dollar quarter. That's thanks to sales of the company's coronavirus vaccine. And I'll be watching for details -- such as future vaccine orders -- that could determine Moderna's path moving forward.

But no matter what Moderna has to say, it will be difficult to top something the company announced last week. Why? This news brings a potential blockbuster product one major step closer to commercialization. In fact, this candidate's next step should be a regulatory submission. Let's take a closer look at what may be Moderna's next billion-dollar revenue driver.

A healthcare worker vaccinates a person in a medical office.

Image source: Getty Images.

The next big product

Last week, Moderna said it dosed the first participant in the phase 3 pivotal trial of its cytomegalovirus (CMV) vaccine candidate. This could become Moderna's next big product. CMV is a common virus. For many people it doesn't develop into something serious. But for others, CMV could be devastating. Unborn babies and people with weakened immune systems are most at risk.

An approved vaccine currently doesn't exist for CMV. And the development programs of most potential competitors are earlier- stage. This means success could offer Moderna the first-to-market advantage. Moderna estimates peak annual revenue for an eventual CMV vaccine would be between $2 billion and $5 billion.

So, this could be an extremely important product for the biotech company. And as I always say about getting to market first, if healthcare providers are satisfied with the product, they are likely to stick with it.

Data so far are promising. Moderna's CMV candidate includes six mRNAs that encode for two viral proteins needed to infect. This technique prepares the body to produce an immune response against both proteins.

Now, exactly how far from commercialization is Moderna? We might think back to coronavirus vaccine development and expect a similar path for the CMV candidate. Unfortunately, investors will have to wait longer this time around. I'll explain.

Coronavirus vaccine versus CMV vaccine candidate

Coronavirus vaccine development benefited from two elements. First, it was easier than usual to enroll volunteers in clinical trials. Considering the pandemic, many people were eager to try a vaccine -- even in experimental stages. Outside of such extreme situations, it isn't always easy to quickly find participants for a clinical trial.

That's why it may take longer to enroll a CMV vaccine trial than a coronavirus vaccine one, even if the target number of participants is much lower. For example, for CMV, Moderna plans on enrolling 8,000 participants across 150 sites globally. Moderna enrolled about 30,000 volunteers in its phase 3 coronavirus vaccine trial.

The second reason the CMV candidate may take longer to reach the market: The U.S. Food and Drug Administration (FDA) offered a fast path to market for COVID-19 vaccine candidates -- Emergency Use Authorization (EUA). The FDA only offers EUAs during public health emergencies such as pandemics. That shortens review time from as long as 10 months to just a few weeks. Moderna, of course, can't apply for emergency authorization for the CMV candidate. So, the potential vaccine won't make it to market nearly as quickly as the coronavirus vaccine.

What does this mean for investors? We're all interested in Moderna's latest sales and profit numbers. And we want to know what lies ahead for the coronavirus vaccine program. But what may be most important is the next big revenue and profit driver down the road -- outside of the coronavirus program. And if all goes smoothly, that could be the CMV vaccine candidate.

That's why investors should keep a close eye on any comments from Moderna about its CMV program -- from trial data to regulatory request timeframe. This candidate may be key to Moderna's transformation from coronavirus vaccine company to an mRNA giant that can cover a wide variety of therapeutic areas.