The Food and Drug Administration granted Moderna's experimental RSV vaccine an expedited review, but Moderna stock tumbled Monday.
The breakthrough designation allows for a speedier development and review period when a drug could treat a serious condition or demonstrate improvement over available therapies. In the case of respiratory syncytial virus, or RSV, there are currently no approved vaccines.
Moderna now joins Pfizer and GSK in the late stages of developing an RSV vaccine for adults age 60 and older. Typically, the virus causes cold-like symptoms. But it can lead to complications in newborns and older adults who have nonexistent or weakened immune systems.
"With this designation, we look forward to productive conversations with the FDA in the hopes of bringing our RSV vaccine candidate for older adults to the market safely and quickly," Moderna Chief Executive Stephane Bancel said in a written statement.
On the stock market today, Moderna stock sank 4.5% to close at 180.87. Pfizer and GSK shares dipped a fraction apiece.
Moderna Stock: Study Is Ongoing
Moderna has tested its RSV vaccine in two final-phase studies. Most recently, the company said its shot was 83.7% effective against lower respiratory tract disease associated with RSV. This is defined as two symptoms of the virus. Against more severe RSV — three or more symptoms — the vaccine proved 82.4% effective. Moderna stock jumped on Jan. 18 when the company unveiled the test results.
The company says its vaccine was generally well tolerated. The most common reactions were injection site pain, fatigue, headache and muscle/joint pain. Moderna says it's study is ongoing, but the company plans to provide an update when it asks for FDA approval.
This puts Moderna just behind Pfizer and GSK, which have already asked the FDA to sign off on their RSV vaccines. The FDA is reviewing theirs for potential approvals in May.
Moderna stock sank in line with its 50-day moving average on Monday, according to MarketSmith.com.
Follow Allison Gatlin on Twitter at @IBD_AGatlin.