Moderna Sees Potential Blockbuster in Investigational Vaccine for Disease That Can Cause Birth Defects

Moderna Therapeutics is inching closer to becoming a commercial company and the company sees a potential blockbuster in an experimental treatment.

Moderna Therapeutics is inching closer to becoming a commercial company and the company sees a potential blockbuster in an experimental treatment for cytomegalovirus (CMV), the most common infectious cause of birth defects in the United States.

On Thursday, Cambridge, Mass.-based Moderna released positive seven-month interim safety and immunogenicity data from its Phase I trial of its CMV vaccine, mRNA-1647. Moderna said the analysis, which was taken after the third and final vaccination, shows continued boosting of neutralizing antibody titers in patients. The findings from the interim analysis build on previously reported data that was collected following two vaccinations. That information was announced at the company’s R&D Day in September. A 12-month interim analysis is planned, which will report safety and immunogenicity through six months after the third vaccination, Moderna said.

As a result of the Phase I study, the company has already launched a Phase IIa trial. The first patient was dosed in the dose-confirmation study. Three-month interim data expected in the second half of 2020. That data will be used to inform a Phase III dose selection, the company said. A Phase III trial could begin in 2021. There is no approved vaccine to prevent CMV in the United States.

Tal Zaks, Moderna’s chief medical officer, said the data from the Phase I interim analysis is significant because, after the third dose, “mRNA-1647 continues to increase durable immune responses that exceed the levels of those with natural CMV infection.”

Moderna’s wholly-owned mRNA-1647 is a vaccine based on the company’s messenger RNA platform. The investigational mRNA-1647 comprises six mRNAs encoding two antigens in one vaccine. Of the six mRNAs, five encode the subunits of the CMV pentamer complex and one mRNA encodes the glycoprotein B (gB) protein, both of which are highly immunogenic. Both pentamer and gB proteins are essential for CMV to enter epithelial cells, which is the first step in CMV infection, the company said. It is designed to protect against CMV infection. Cytomegalovirus is a common pathogen and is the leading infectious cause of birth defects in the United States with approximately 25,000 newborns in the U.S. infected every year. CMV is passed from the mother to her unborn child. Birth defects occur in about 20% of infected babies. The defects can include neurodevelopmental disabilities such as hearing loss, vision impairment, varying degrees of learning disability and decreased muscle strength and coordination.

“There is no approved vaccine to prevent CMV infection despite repeated attempts over the last 50 years. With mRNA-1647, which encodes for both the pentamer and gB antigens, we believe we can significantly reduce the burden of CMV infection, including in women of childbearing age,” Zaks said in a statement.

Stéphane Bancel, Moderna’s chief executive officer, said prevention of CMV is an urgent unmet medical need. He said they believe the mRNA-1647 program as a potential blockbuster commercial opportunity. Moderna’s mRNA-1647 is the first mRNA vaccine for an infectious disease to enter a Phase II clinical trial, Bancel said.

“These new data, after the third vaccination, represent another critical clinical milestone in our CMV vaccine program and we are extremely pleased with this continued progress as we move into late-stage development, prepare for a pivotal Phase III study as quickly as possible and ensure commercial readiness,” Bancel said in a statement.

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