Moderna doses first patient in Phase 3 trial mRNA cytomegalovirus vaccine

Moderna CEO Stéphane Bancel has stressed that the company is not just a COVID-19 vaccine maker.

Now, Cambridge, Massachusetts–based Moderna (NSDQ:MRNA) has announced that its mRNA-based cytomegalovirus (CMV) vaccine candidate is entering a Phase 3 pivotal registration study.

“Moderna has been focusing on a vaccine against CMV for a number of years,” said Lori Panther, vice president, clinical development, infectious diseases at Moderna. “We’re very excited to launch this Phase 3 trial.”

While there are currently no licensed CMV vaccines available, researchers have worked on developing such a vaccine for decades. In 1999, the Institute of Medicine assigned a CMV vaccine the highest priority in its assessment of targets for vaccine development. “It’s certainly an unmet medical need,” Panther said.

Known as mRNA-1647, the investigational vaccine integrates six mRNAs in a single vaccine.

Dr. Lori Panther

Five mRNAs encode the subunits that form the membrane-bound pentamer complex. The sixth mRNA encodes the full-length membrane-bound glycoprotein B (gB). “The pentamer antigen actually plays a pretty significant role in terms of viruses’ ability to enter and infect cells,” Panther said.

CDC notes that more than half of U.S. adults have been infected with CMV by the age of 40. Expectant mothers can pass the virus on to unborn children. One out of 200 newborns has the virus. Roughly one in five babies with the virus has health problems stemming from the infection, including jaundice, low birth weight, hearing loss, seizures and blindness. In addition, CMV in newborns is often linked to congenital disabilities in the U.S.

“Mothers aren’t screened for CMV infection during their pregnancy,” Panther said. “That would require a lot of infrastructure and a lot of cost to periodically screen mothers throughout pregnancy.”

“We believe that our mRNA vaccine technology is well-suited to provide protection against this latent virus,” Bancel said in a news release.

Moderna is referring to the Phase 3 study as “CMVictory.” It is the second Phase 3 study in its history.

The CMVictory trial will be powered to show vaccine efficacy with biostatistical power in the seronegative population. The study will also include seropositive participants.

The company is also developing vaccine candidates for Epstein-Barr virus (EBV), human immunodeficiency virus (HIV), herpes simplex virus (HSV), varicella-zoster virus (VZV), among others.

Moderna said it intends to optimize for diversity in the clinical trial.