Phase 2b Study of an Ad26.RSV.preF Vaccine for Prevention of RSV-mediated Respiratory Tract Disease in Older Adults

• Published in: Innovation in aging 2021-12, Vol.5 (Supplement_1), p.1042-1042
• Main Authors: Falsey, Ann, Williams, Kristi, Gymnopoulou, Efi, Bart, Stephan, Ervin, John, De Paepe, Els, Comeaux, Christy, Heijnen, Esther
• Format: Article
• Language: English
• Subjects: Abstracts
• ISSN: 2399-5300; 2399-5300
• DOI: 10.1093/geroni/igab046.3723

Respiratory syncytial virus (RSV) may cause serious lower respiratory tract disease (LRTD) in older adults, and there is currently no licensed vaccine. CYPRESS (NCT03982199) is a randomized, double-blind, placebo-controlled Phase 2b proof-of-concept trial of an Ad26.RSV.preF-based vaccine for the prevention of RSV-mediated LRTD in older adults. Adults aged ≥65 years were randomized 1:1 before the RSV season to receive Ad26.RSV.preF-based vaccine or placebo. Acute respiratory infection symptoms were collected through a patient eDiary and/or clinician assessment until the end of the RSV season. The primary endpoint was the first occurrence of RTPCR-confirmed RSV-mediated LRTD according to any of 3 case definitions: (1) ≥3 symptoms of lower respiratory tract infection (LRTI), (2) ≥2 symptoms of LRTI, or (3) ≥2 symptoms of LRTI or ≥1 symptom of LRTI with ≥1 systemic symptom. Immunogenicity was assessed in a subset of approximately 200 participants. A total of 2891 participants in each study arm received study treatment. Vaccine efficacy was 80% (94.2% CI, 52.2-92.9%), 75% (50.1-88.5%), and 69.8% (43.7-84.7%) for case definition 1, 2, and 3, respectively (all P