Pfizer Announces Positive Results from Pivotal Phase 3 Trial of Abrysvo
Pfizer announces positive results from pivotal phase 3 trial of Abrysvo for RSV in immunocompromised adults
Overview
Pfizer Inc. announced positive top-line safety and immunogenicity results from substudy B of the ongoing pivotal phase 3 clinical trial (NCT05842967) MONeT (RSV I Mmunizati ONStudy for Adul Ts at Higher Risk of Severe Illness), evaluating two doses of Abrysvo vaccine in immunocompromised adults aged 18 and older at risk of developing severe respiratory syncytial virus (RSV)-associated lower respiratory tract disease (LRTD).
More prone for RSV-LRTD
- Adults with immunocompromising conditions have an increased risk of developing RSV-LRTD.
- Substudy B of the MONeT trial was conducted to assess the safety and immunogenicity of two doses of Abrysvo, administered one month apart, in four groups of immunocompromised adults:
*those with non-small cell lung cancer, those on haemodialysis due to end-stage renal disease,
*those with autoimmune inflammatory disorder receiving active immunomodulator therapy, and solid organ transplant recipients.
- Of the 203 adults enrolled in the substudy, approximately half were between the ages of 18 to 59, and approximately half were 60 years or older.
About Abrysvo
- Abrysvo was well-tolerated during the trial, showing a safety profile consistent with findings from other studies of the vaccine.
- While the company evaluated two doses, a single 120 µg dose of Abrysvo generated a strong neutralizing response against both subtypes of RSV, RSV-A and RSV-B, across all cohorts and age groups in the study.
- Pfizer plans to share these findings at an upcoming scientific conference and publish them in a peer-reviewed scientific journal, as well as submit these data to the regulatory agencies for review.
From Vaccine Research and Development Section: Pfizer
- “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 US,” said Annaliesa Anderson, Ph.D., senior vice president and chief scientific officer, vaccine research and development, Pfizer.
- “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.”
About the Previous Trials and Outcomes
- These most recent data in immunocompromised adults build on the body of evidence supporting the profile of Abrysvo in high-risk adults.
- In June of 2024 at the meeting of the Advisory Committee on Immunization Practices ( ACIP ), Pfizer presented results from a cohort of adults aged 18-59 with certain chronic medical conditions.
- In the double-blinded study, 681 adults aged 18 to 59 with chronic conditions were randomized 2:1 to receive a single dose of Abrysvo or placebo.
- Participants demonstrated RSV-A and RSV-B subgroup neutralizing responses non-inferior to the response seen in the phase 3 (NCT05035212) RENOIR study of Abrysvo, which previously demonstrated Abrysvo’s efficacy in a population of adults aged 60 or older.
- These results support previous data presented at the ACIP showing high Abrysvo clinical effectiveness against lower respiratory tract disease among a population of adults age 60 years and older that included a substantial proportion of immunocompromised persons.
FDA Approval for ACT-O-VIAL Presentation of Abrysvo
- Additionally and as previously announced, the US Food and Drug Administration (FDA) has approved Pfizer’s supplemental Biologics License Application for the ACT-O-VIAL presentation of Abrysvo.
- This approval allows Pfizer to bring a new option to market alongside its existing needle-free reconstitution kits.
- The ACT-O-VIAL System is a dual-component vial system that simplifies the reconstitution of Abrysvo within a single, compact device.
- Designed to support safety, workflow improvements and storage efficiency, the system offers significant storage space savings, which may be appealing to retailers during peak vaccination seasons.
About MONeT Trial
- MONeT (RSV I Mmunizati ONStudy for Adul Ts at Higher Risk of Severe Illness) is a phase 3, 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 is 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 is an open-label study that enrolled approximately 200 immunocompromised adults aged 18 or older, roughly half of which were aged 60 or older, who received two doses of Abrysvo, one month apart.
About Respiratory Syncytial Virus
- 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.
- 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.
Sole RSV Vaccine
- 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 protection against 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.
FDA approval for Abrysvo in 2023
- In May 2023, the FDA approved Abrysvo for the prevention of LRTD caused by RSV in individuals 60 years of age or older.
- The Advisory Committee on Immunization Practices (ACIP) of the US Centers for Disease Control and Prevention recommends RSV vaccines as a single dose for all adults 75 and older and for adults 60 and older at increased risk of severe RSV disease.
- 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.
EMA Marketing Authorization for Abrysvo
- 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.
In addition to MONeT, Pfizer has initiated a clinical trial evaluating Abrysvo in children ages two to less than 18 years who are at higher risk for RSV disease.
About Abrysvo
Abrysvo is a vaccine indicated in the US for: the prevention of lower respiratory tract disease (LRTD) caused by respiratory syncytial virus (RSV) in people 60 years of age and older; pregnant individuals at 32 through 36 weeks gestational age for the prevention of LRTD and severe LRTD caused by RSV in infants from birth through 6 months of age.
