Moderna (MRNA -1.11%) has taken another step closer to making its dream of commercializing a coronavirus vaccine a reality. The company just released more detailed interim results from its phase 1 trial -- and they are enough for Moderna and investors to cheer about.

What's so encouraging about the results? And do they really bring Moderna close to victory? Let's take a look.

A researcher draws a dose of vaccine from a vial.

Image source: Getty Images.

Moderna's trial included 45 healthy volunteers ranging from 18 to 55 years old. Each participant was given two doses of mRNA-1273 28 days apart in one of three dosage levels. Based on the results, Moderna chose to pursue the 100-microgram dose -- the mid-range dose -- in late-stage trials.

Neutralizing antibody levels

The key positive in the phase 1 data has to do with neutralizing antibodies. These are the antibodies that actually block infection, so the ability of a vaccine to stimulate their production is crucial. Moderna, in a publication in The New England Journal of Medicine, reported that all evaluated trial participants showed neutralizing antibody production. And in the 100-microgram dosage group, levels were four times higher than those seen in recovered COVID-19 patients.

Initial data released in May only showed neutralizing antibody data for eight trial participants. While the neutralizing antibody levels came in at or above those of patients who had suffered from COVID-19, the sample wasn't big enough to demonstrate a clear trend. This latest report of neutralizing antibody production in all participants is a big step forward. Results also showed T-cell responses following the second dose in the lower-dosage group and in the 100-microgram dose. T cells are another important piece of the puzzle as they are an immune system tool to detect and fight infection.

Moderna will aim to replicate that positive data in as many as 30,000 people when the company begins phase 3 studies on July 27.

A step closer to the finish line

All of this is good news for Moderna. The biotech company has taken a step closer to the finish line. But others have been catching up. Moderna isn't as far ahead as it was several weeks ago.

AstraZeneca (AZN 1.67%) is conducting a phase 2/3 trial now. The U.S. Food and Drug Administration recently granted the Pfizer (PFE 0.91%) and BioNTech (BNTX 0.29%) team Fast Track designation for two vaccine candidates. Pfizer and BioNTech, like Moderna, are developing a vaccine using messenger RNA. They aim to begin a phase 2b/phase 3 trial in 30,000 participants later this month. Moderna, AstraZeneca, and the Pfizer and BioNTech team are among a handful of drugmakers closest to the finish line right now. 

Inovio Pharmaceuticals (INO 2.45%) and Novavax (NVAX 1.16%) are close behind. Inovio plans to begin a phase 2/3 study this summer, and Novavax expects to release phase 1/2 interim data at the end of this month and then begin the phase 2 part of the study shortly thereafter.

Of course, that list of "who is ahead" is all from a timeline perspective. What, ultimately, is most important -- and will determine the winner or winners -- is the safety and efficacy of the vaccine candidate. Though Moderna's results are encouraging, we still should rein in excitement.

Here's why: First there's the question of neutralizing antibodies. It's still not clear how long neutralizing antibodies will remain in the body and what level of antibodies is needed to prevent infection. Another question is the vaccine's performance in the elderly, a group heavily hit by COVID-19. A successful vaccine must be safe and effective in this population. Moderna is testing the vaccine in older and elderly volunteers in phase 2 and will also include these groups in phase 3.

What does this mean for investors?

Moderna shares have climbed 315% since the start of the year. The company doesn't yet have products on the market. Besides the COVID-19 vaccine, Moderna's most advanced candidate is in phase 2 studies. That means if Moderna's vaccine fails, the company is still years away from commercializing a product.

In the near term, with any good news, this biotech stock likely has more to gain. And if Moderna's vaccine is successful, the shares may skyrocket. But if the company loses this race or produces a vaccine that isn't as strong as a rival's, the result may be devastating for the shares. That's why, for now, long-term investors may want to watch Moderna's final sprint to the finish from the sidelines.