A vaccine Moderna has long been developing for the world’s most common congenital infection has failed a Phase 3 trial.
The biotechnology company said late Wednesday that the shot, dubbed mRNA-1647, missed its main goal in a late-stage trial against cytomegalovirus, or CMV. The vaccine was only between 6% to 23% effective at preventing infections in the study, which enrolled nearly 7,500 women between 16 and 40 years of age. Those efficacy numbers were “well below” Moderna’s target, leading the company to stop further testing of the vaccine against CMV. Only a Phase 2 study in bone marrow transplant patients will continue.
"Today's announcement is disappointing for families and healthcare professionals who have been eagerly awaiting a CMV vaccine," Moderna CEO Stéphane Bancel said in the statement.
Bancel added that the “majority of the data” from the trial are still forthcoming, and will be shared with the scientific community so “our learnings can contribute to the continued pursuit of a CMV vaccine.”
Though it doesn’t trigger symptoms for most people, CMV can cause serious health problems for those with weakened immune systems. It’s also a leading cause of birth defects, as babies born with it can have developmental delays and other long-term issues like hearing loss.
There are no vaccines available to prevent CMV infections. Moderna has long sought to change that with mRNA-1647 and, before its ascent to stardom during the pandemic, envisioned it as a future blockbuster. Some analysts projected $3 billion in peak annual sales for mRNA-1647, if it were to prove successful in a late-stage trial.
A positive outcome became more critical for Moderna over the last couple years. The company’s stock price has plummeted amid declining COVID-19 vaccine sales and revised financial forecasts that have eroded confidence in its management team and spurred a restructuring. Uptake of a second shot for respiratory syncytial virus has been slow. The change in leadership at U.S. public health agencies has hurt, too, leading to narrower clearances for COVID shots and skepticism of the messenger RNA technology Moderna is known for.
Investor optimism surrounding the CMV program had diminished in recent months, according to Leerink Partners analyst Mani Foroohar. The vaccine didn’t clear an early bar for declaring study success in January, and afterwards, Moderna updated its statistical analysis plan, suggesting the odds of success were “dwindling,” Foroohar wrote in August.
“Like most investors, we saw CMV failure [as] a matter of when, not if,” Foroohar added in a Wednesday client note.
Despite the study setback, Moderna doesn’t expect any impact to its current financial forecasts or ability to break even in 2028. Still, it faces greater pressure to turn around slowing respiratory vaccine sales until its oncology portfolio can become a “meaningful” contributor, Foroohar wrote.
