The FDA has approved the first vaccine for respiratory syncytial virus, a pathogen that typically circulates in the fall and winter months, leading to serious and potentially deadly infections, particularly in infants and the elderly.
The Wednesday approval of the vaccine, known in development as RSVPreF3 OA, covers the prevention of RSV infection in adults age 60 and older. GSK will market its new product under the brand name “Arexvy.” The British pharmaceutical giant said it plans to launch its new vaccine before the 2023/2024 RSV season. In April, the European Medicines Agency’s Committee for Medicinal Products for Human Use recommended approval of the GSK RSV vaccine. A decision in Europe is expected in coming months.
“Our focus now is to ensure eligible older adults in the U.S, can access the vaccine as quickly as possible and to progress regulatory review in other countries,” GSK Chief Scientific Officer Tony Wood said in a prepared statement.
Though RSV can infect anyone, people with strong immune systems usually fight off the virus experiencing symptoms no more serious than those of the common cold. But in infants who have narrow breathing passages and immune systems that are still developing, RSV infection can become deadly. The infection is also serious in the elderly, who may have weaker immune systems or underlying conditions that put them at higher risk of complications. RSV infection can lead to lower respiratory tract disease, such as pneumonia and bronchiolitis. According to the Centers for Disease Control and Preventioneach year RSV leads to an estimated 60,000 to 160,000 hospitalizations in those 65 and older, and an estimated 6,000 to 10,000 deaths in that age group.
Arexvy is designed to spark an immune response to RSV F, a protein on the surface of the virus that it uses to fuse to and enter a cell. The vaccine contains an engineered part of a prefusion form of RSV F (RSVPref3). This antigen is combined with a proprietary GSK adjuvant, an ingredient that boosts the immune response.
Arexvy is being evaluated in an ongoing placebo-controlled Phase 3 study enrolling about 25,000 participants in the U.S. and around the world. The study is designed to assess a single dose of the GSK vaccine. The study will follow participants for two additional RSV seasons to assess how long the shot’s effects last as well as the safety and efficacy of repeat vaccination.
The FDA based its approval on data from the first RSV season. Those results showed the vaccine significantly reduced the risk of developing RSV-associated lower respiratory tract disease by 82.6%. Results also showed the shot reduced the risk of developing severe lower respiratory tract disease by 94.1%. GSK first reported those Phase 3 results last October.
In the clinical trial results so far, the FDA said the most commonly reported side effects in a subset of those in the vaccination group included injection site pain, fatigue, muscle pain, headache, and pain and joint stiffness. The agency also noted that across the entire study population, atrial fibrillation was reported within 30 days in 10 participants who received Arexvy and four who were injected with a placebo.
More serious problems may be associated with interactions with other vaccines. In one other study testing Arexvy in those 60 and older, the FDA said some participants received the GSK vaccine at the same time they received an approved influenza vaccine. Two of those participants developed acute disseminated encephalomyelitis (ADEM), a rare type of brain and spinal cord inflammation. One of those who developed this type of inflammation died. In yet another study testing Arexvy in older adults, a participant developed Guillain-Barré syndrome, a rare condition in which the body’s immune system damages nerve cells, causing muscle weakness and even paralysis.
The FDA is requiring GSK to conduct a post-marketing study to assess the risk signs for both Guillain-Barré syndrome and ADEM. The FDA also said GSK has committed to assess atrial fibrillation in the post-marketing research, though the agency is not requiring the company to do so.
Other companies are on GSK’s heels with their own RSV vaccines. Pfizer’s RSV vaccine for adults is still under FDA review. Moderna has said it expects to submit an application for its RSV vaccine in the first half of this year. Johnson & Johnson formally withdrew from the RSV vaccine race in March. Though J&J’s shot led to strong results in mid-stage testing, the company stopped a Phase 3 study as part of what it described as a reprioritization of assets.
Image by GSK