Messenger RNA (mRNA) coronavirus vaccine candidates now appear to be batting two for two. Pfizer (PFE 2.40%) and BioNTech (BNTX 0.74%) announced great interim efficacy results for their experimental mRNA COVID-19 vaccine last week. This week, Moderna (MRNA -0.58%) followed up with fantastic efficacy results for its mRNA vaccine candidate.

It certainly seems as if the mRNA approach could be just the ticket for delivering a safe and effective vaccine to help turn the tide against the coronavirus. Are there other biotech stocks with mRNA vaccine programs that could also be winners? Absolutely. Here are three mRNA coronavirus vaccine stocks to check out that aren't Pfizer, BioNTech, or Moderna.

mRNA vaccine printed on the label of a vial held in a gloved hand.

Image source: Getty Images.

1. CureVac

CureVac (CVAC), like BioNTech, is a German biotech company focused on mRNA vaccine development. It's a little smaller than BioNTech, though, which could give the stock even more room to run if its mRNA COVID-19 vaccine CVnCoV proves successful.

The company announced encouraging interim results from a phase 1 study of CVnCoV earlier in November. Similar to the early stage results for the coronavirus vaccine candidates developed by Pfizer/BioNTech and Moderna, CVnCoV demonstrated a robust immune response in participants receiving two doses.

CureVac is currently evaluating its experimental vaccine in a phase 2a study in older adults in Panama and Peru. It expects to begin a phase 2b/3 study by the end of this year.

In addition to its COVID-19 vaccine candidate, CureVac's pipeline includes one other experimental mRNA vaccine for rabies in phase 1 testing. The biotech is also evaluating two RNA-based cancer immunotherapies in early stage clinical studies. 

2. Arcturus Therapeutics

Arcturus Therapeutics (ARCT -1.29%) ranks as the smallest of the biotechs with clinical-stage mRNA coronavirus vaccine candidates, with its market cap at only a little over $1 billion. The company could grow significantly, though, if experimental COVID-19 vaccine ARCT-021 fulfills its potential.

The interim results from a phase 1/2 study of ARCT-021 announced last week looked great. Arcturus reported promising immune system responses for the experimental vaccine, along with an encouraging safety profile. Even better, ARCT-021 could be effective with only one dose. Most of the leading coronavirus vaccines require two doses.

Arcturus is already talking with Singapore's Health Sciences Authority about advancing ARCT-021 into later-stage clinical studies. The company expects to initiate discussions over the next few weeks with other regulatory agencies about a path to late-stage testing of its COVID-19 vaccine candidate.

The biotech's pipeline features one other clinical-stage program, ARCT-810, an experimental therapy targeting rare genetic disease ornithine transcarbamylase (OTC) deficiency. This candidate is currently being evaluated in a phase 1b study. 

3. Translate Bio

Translate Bio (TBIO) lags behind Arcturus and CureVac with its coronavirus vaccine program. The Massachusetts-based biotech recently reported positive results from a preclinical study of mRNA-based COVID-19 vaccine candidate MRT5500.

It shouldn't be very long before Translate Bio advances MRT5500 into clinical testing in humans, though. The company plans to begin a phase 1/2 study of the experimental vaccine before the end of 2020.

Translate Bio's mRNA technology attracted the attention of a big drugmaker. Sanofi first teamed up with Translate Bio in 2018 to develop mRNA vaccines for up to five infectious disease pathogens. This partnership was expanded earlier this year to include a COVID-19 vaccine, then later changed to develop mRNA vaccines for all infectious diseases. 

Currently, Translate Bio has only one clinical-stage program, MRT5005. The mRNA therapeutic candidate is in a phase 1/2 clinical study for treating the underlying cause of cystic fibrosis. 

Still early

It's still too early to know if any of these mRNA coronavirus vaccine stocks will ultimately be successful. However, with the good news so far for Pfizer, BioNTech, and Moderna, the future could be promising for CureVac, Arcturus, and Translate Bio.