The approval of Arexvy by the US Food and Drug Administration (FDA) is specifically for the prevention of lower respiratory tract disease caused by RSV in adults aged 60 years and above. The decision was based on positive results from the phase 3 trial AReSVi-006, which showed an efficacy of more than 80% in older adults.
“Today marks a turning point in our effort to reduce the significant burden of RSV. Arexvy is the first approved RSV vaccine for older adults, expanding GSK’s industry-leading vaccine portfolio, which protects millions of people from infectious diseases each year,” said Tony Wood, Chief Scientific Officer of GSK.
“Our focus now is to ensure eligible older adults in the US can access the vaccine as quickly as possible and to progress regulatory review in other countries.”
RSV has lacked a vaccine
RSV is a common viral infection that affects the lungs and breathing passages. The infection can lead to pneumonia, hospitalisation and death and is particularly dangerous for older adults due to pre-existing conditions and weakened immune systems.
Despite more than 60 years of research, there had been no vaccine approved for RSV prior to Arexvy. This is due to a mixture of factors, with one being that the virus can evolve its surface proteins fast, making it difficult for the immune system to catch up.
Arexvy consists of a fragment of a protein that RSV uses to infect cells, training the immune system to watch out for the infection. The vaccine also contains a liposome-based adjuvant that boosts the function of T cells, which are key for effective immunity against viral infections.
The path to commercialization
Arexvy met its primary goal in AReSVi-006 in 2022, and this led the US FDA’s Vaccines and Related Biological Products Advisory Committee to vote in favor of approval in March 2023. The commercial launch of the vaccine in the US is planned for the incoming 2023/24 RSV season around winter, and GSK is exploring the possibility of providing shots annually.
Following the US FDA’s positive decision, GSK is expecting approval decisions from regulatory agencies in Europe (receiving a positive CHMP decision last week), Japan and other countries later this year.
The development of GSK’s RSV vaccine is ongoing in other clinical programs. GSK is testing the vaccine in a phase 3 trial in adults aged between 50 and 59 years, with the results due this year. The firm is also running two late-stage clinical trials of the RSV vaccine in combination with flu vaccines in older adults, and results are due by June 2023.
RSV showdown
GSK’s Arexvy is likely to be followed closely by other RSV candidates into the market. A candidate developed by Pfizer for protection in older adults was given a positive vote by the US FDA advisory committee in late February 2023, with a final approval decision expected by the end of May. Pfizer is awaiting an FDA decision on its RSV candidate for use in pregnant mothers for the protection of newborn infants, with the decision date set to August 2023.
Meanwhile, the messenger RNA giant Moderna is developing its own vaccine candidate for RSV, with positive phase 3 results announced in January 2023.