Drugmaker Pfizer has released that the data from the phase 3 clinical trial of its vaccine, Abrysvo for the treatment of severe respiratory syncytial virus (RSV)-associated lower respiratory tract disease (LRTD).
According to the company’s statement, the ongoing trial focuses on evaluating a single dose of Abrysvo versus placebo in adults 18 to 59 years of age at risk of developing the disease.
“Adults with certain underlying chronic conditions are at increased risk of developing, and being hospitalized for, RSV-associated LRTD. Among US adults 18 to 49 years of age, 9.5 per cent have a chronic condition that puts them at risk of severe RSV disease and this percentage rises to 24.3 per cent among persons 50 to 64 years of age. However, no RSV vaccines have been approved for use in adults 18 to 59 years of age. The MONeT study was initiated to address this significant unmet need by investigating the immunogenicity and safety of Abrysvo in adults aged 18 to 59 at increased risk for RSV disease, such as those with asthma, diabetes, and chronic obstructive pulmonary disease,” the company said in a statement.
During the trial, Abrysvo was well-tolerated, and safety findings were consistent with those from previous investigations of Abrysvo in other populations, the company stated.
Pfizer also met its diversity recruitment goals for the study providing data from participants that mirror the diverse US population and had a balanced representation across underlying medical conditions, it stated.
Pfizer intends to submit these data to regulatory agencies and request expansion of the age group from the current indication to 18 years of age and older, the company informed. Moreover, the company also intends to publish these findings in a peer-reviewed scientific journal and share them at an upcoming scientific conference.
“These encouraging results provide evidence that Abrysvo can help protect adults with increased risk against RSV-associated illness,” said Annaliesa Anderson, Ph.D., senior vice president and head, vaccine research and development, Pfizer. “We are excited to address a significant unmet need, pending regulatory authority approval, as Abrysvo has the potential to become the first and only RSV vaccine for adults 18 years and older.”
Respiratory syncytial virus (RSV) is a contagious virus and a common cause of respiratory illness. The virus can affect the lungs and breathing passages of an infected individual and can potentially cause severe illness in young infants, older adults, and individuals with certain chronic medical conditions. In the United States alone, among older adults, RSV infections account for approximately 60,000-160,000 hospitalizations and 6,000-13,000 deaths each year. RSV disease is caused by the respiratory syncytial virus. There are two major subgroups of RSV: RSV-A and RSV-B. Both subgroups cause disease and can co-circulate or alternate predominance from season to season.
Pfizer currently is the only company with an RSV vaccine to help protect older adults as well as infants through maternal immunization. Abrysvo is a bivalent vaccine that was designed to provide broad protection against all RSV-LRTD, regardless of the virus subgroup. In the prefusion state, the RSV fusion protein (F) is a major target of neutralizing antibodies, serving as the basis of Pfizer’s RSV vaccine. Variations in the F protein sequence among RSV-A and RSV-B subgroups are clustered in a key antigenic site, a target for potent neutralizing antibodies.
In May 2023, the FDA approved Abrysvo for the prevention of LRTD caused by RSV in individuals 60 years of age or older. This was followed by the ACIP’s recommendation of the vaccine for use in adults 60 years of age and older based on shared clinical decision making, which occurred in June 2023. In August 2023, the FDA approved Abrysvo for the prevention of LRTD and severe LRTD caused by RSV in infants from birth up to six months of age by active immunization of pregnant individuals at 32 through 36 weeks gestational age. This was followed in September 2023 with ACIP’s recommendation for maternal immunization to help protect newborns from RSV seasonally where the vaccine should be administered from September through January in most of the continental United States.
Also in August 2023, Pfizer announced that the European Medicines Agency (EMA) granted marketing authorization for Abrysvo for both older adults and maternal immunization to help protect infants. The vaccine has also received approvals from la Administración Nacional de Medicamentos, Alimentos y Tecnología Médica (ANMAT) of Argentina in September 2023; the Medicines and Healthcare products Regulatory Agency (MHRA) of the United Kingdom in November 2023; Health Canada in January 2024; the Pharmaceutical Administration Bureau of Macau in February 2024; the Ministry of Health, Labour, and Welfare of Japan for maternal immunization to help protect infants in January 2024 and for older adults in March 2024; and the Therapeutic Goods Administration of Australia in March 2024 for older adults.
