Efficacy and Safety of Clesrovimab (MK-1654) in Infants (MK-1654-004)

Summary

The primary objectives of this phase 2b/3 double-blind, randomized, placebo-controlled study are to evaluate the efficacy and safety of clesrovimab in healthy pre-term and full-term infants. It is hypothesized that clesrovimab will reduce the incidence of respiratory syncytial virus (RSV)-associated medically attended lower respiratory infection (MALRI) from Days 1 through 150 postdose compared to placebo.

Timeline

Start

2021-04-07

Primary completion

2024-07-09

Completion

2024-07-09

Outcome

Met primary endpoint

registry RSV Season 1: Clesrovimab 105 mg vs RSV Season 1: Placebo; p <0.001; Efficacy estimate 60.4 (95% CI 44.1 to 71.9) NCT04767373 ↗

release “本試験の有効性の主要評価項目として、投与後150日目（5カ月目）までにRSウイルス関連の医療介入が必要となった下気道感染症（MALRI: medically attended lower respiratory infections）（下気道感染症（LRI）または重症度の指標が1つ以上）の発生率をプラセボと比較したところ、60.4%（95% CI: 44.1, 71.9, p<0.001）低下しました。” msd.co.jp ↗

Publications

• Zar HJ, Simoes EAF, Madhi SA, Ramilo O, Senders SD, Shepard JS, Laoprasopwattana K, Piedrahita J, Novoa JM, Vargas SL, Dionne M, Jackowska T, Liu E, Ishihara Y, Ikeda K, Zhang Y, Railkar RA, Lutkiewicz J, Vora KA, Zang X, Maas BM, Lee AW, Guerra A, Sinha A; CLEVER (MK-1654-004) Study Group. Clesrovimab for Prevention of RSV Disease in Healthy Infants. N Engl J Med. 2025 Oct 2;393(13):1292-1303. doi: 10.1056/NEJMoa2502984. Epub 2025 Sep 17.
• Ginsburg AS, Srikantiah P. Respiratory syncytial virus: promising progress against a leading cause of pneumonia. Lancet Glob Health. 2021 Dec;9(12):e1644-e1645. doi: 10.1016/S2214-109X(21)00455-1. Epub 2021 Nov 11. No abstract available.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	Clesrovimab	Monoclonal antibody	105 mg	Intramuscular

Indications