Abrysvo Demonstrates Safety and Efficacy as an RSV Vaccine in Immunocompromised Adults

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Pfizer announced top-line results from the ongoing Phase III MONeT (RSV IMmunizatiON Study for AdulTs at Higher Risk of Severe Illness), which is evaluating two doses of the Abrysvo in immunocompromised adults aged 18 and older at risk of developing severe RSV-associated lower respiratory tract disease (LRTD). According to the company, the study demonstrates Abrysvo’s potential to meet a critical need in a vulnerable population with no currently approved RSV vaccines for adults under 60 in the United States.¹

“Immunocompromised adults, such as patients with cancer or autoimmune disorders, have a substantially increased risk of experiencing severe complications from RSV, yet there are currently no vaccines approved for those aged 18 to 59 in the U.S.,” said Annaliesa Anderson, PhD., SVP, chief scientific officer, vaccine research and development, Pfizer, in a press release. “We are encouraged by the positive top-line data from this study, which provide important evidence that Abrysvo has the potential to address a significant unmet need in this vulnerable population.”

MONeT was a multicenter clinical trial (NCT05842967) investigating the safety, tolerability and immunogenicity of Abrysvo in adults at risk of RSV-associated disease, including adults with certain chronic medical conditions (substudy A) and adults who are immunocompromised (substudy B). Substudy A was classified as a double-blinded study that randomized 681 adults aged 18 to 59 with chronic conditions, with 2:1 to receive a single dose of Abrysvo or placebo, Substudy B was an open-label study that enrolled approximately 200 immunocompromised adults aged 18 or older, with close to half being over the age of 60 years old. This group received two doses a month apart. All participants had conditions such as non-small cell lung cancer, end-stage renal disease requiring hemodialysis, autoimmune inflammatory disorders, or were recipients of solid organ transplants.

Other than being reported as well tolerated, results found that its safety profile was consistent with previous studies. Notably, a single 120 µg dose of Abrysvo generated strong neutralizing responses against RSV-A and RSV-B across all age groups and cohorts. Pfizer stated that it plans on presenting these findings at a scientific conference, submit the data to regulatory agencies, and publish them in a peer-reviewed journal.

Pfizer warns against the use of Abrysvo in patients with a history of severe allergic reaction to any of its components. Additionally, adults with a weakened immune system may have a reduced reaction, fainting is common after injection, and it might not protect everybody dosed with it.¹

According to the Centers for Disease Control and Prevention (CDC), RSV leads to 2.1 million outpatient visits among children younger than five years old on an annual basis in the United States. Further, it leads to anywhere from 58,000-80,000 hospitalizations among children in that age group, 60,000-160,000 hospitalizations among adults over the age of 65 years old, 6,000-10,000 deaths among adults over 65 years old, and 100–300 deaths in children younger than five years old.²

“Prior to 2020, seasonal patterns for RSV in the United States were very consistent. However, the patterns of circulation for RSV and other common respiratory viruses have been disrupted since the start of the COVID-19 pandemic early in 2020. Beginning in the southern region of the United States, RSV circulation began to rise in the spring months of 2021 and peaked in July. It is too soon to predict when the previous seasonal patterns will return,” reports the CDC.

References

1. Pfizer Announces Top-Line Results of ABRYSVO® for RSV in Immunocompromised Adults. Business Wire. August 12, 2024. Accessed August 13, 2024. https://www.businesswire.com/news/home/20240812622927/en/Pfizer-Announces-Top-Line-Results-of-ABRYSVO%C2%AE-for-RSV-in-Immunocompromised-Adults

2. Surveillance of RSV. CDC. Accessed August 13, 2024. https://www.cdc.gov/rsv/php/surveillance/index.html#:~:text=Each%20year%20in%20the%20United,younger%20than%205%20years%20old.&text=58%2C000%2D80%2C000%20hospitalizations%20among%20children%20younger%20than%205%20years%20old.&text=60%2C000%2D160%2C000%20hospitalizations%20among%20adults%2065%20years%20and%20older.