Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the U.S. Food and Drug Administration (FDA) has approved ENFLONSIA™ (clesrovimab-cfor) for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates (newborns) and infants who are born during or entering their first RSV season.

默克公司（纽约证券交易所代码：MRK），在美国和加拿大以外地区称为MSD，今天宣布美国食品和药物管理局 (FDA) 已批准ENFLONSIA™（clesrovimab-cfor）用于预防新生儿（出生婴儿）和在第一个呼吸道合胞病毒（RSV）季节期间出生或进入的婴儿的RSV下呼吸道疾病。

ENFLONSIA is a preventive, long-acting monoclonal antibody (mAb) designed to provide direct, rapid and durable protection through 5 months, a typical RSV season, with the same 105 mg dose regardless of weight. A typical RSV season usually spans autumn to spring of the next year..

ENFLONSIA 是一种预防性、长效单克隆抗体 (mAb)，旨在通过同一剂量（105 毫克，无论体重如何）提供直接、快速且持久的保护，持续时间覆盖典型的 5 个月 RSV 流感季。典型的 RSV 流感季通常从秋季持续到次年春季。

“RSV disease is the leading cause of infant hospitalization in the U.S. and can lead to serious respiratory conditions like bronchiolitis and pneumonia,” said Dr. Octavio Ramilo, chair of the Department of Infectious Diseases at St. Jude Children’s Research Hospital and investigator for the CLEVER (MK-1654-004) and SMART (MK-1654-007) trials.

“RSV 疾病是美国婴儿住院的主要原因，可能导致支气管炎和肺炎等严重的呼吸道疾病，”圣犹大儿童研究医院传染病科主任、CLEVER (MK-1654-004) 和 SMART (MK-1654-007) 试验的首席研究员 Octavio Ramilo 博士说道。

“ENFLONSIA combines dosing convenience with strong clinical data showing significant reductions in RSV disease incidence and hospitalizations, making it a promising new intervention to help protect infants from RSV.”.

“ENFLONSIA 将剂量便利性与显示 RSV 疾病发病率和住院率显著降低的有力临床数据相结合，成为一种保护婴儿免受 RSV 侵害的有前景的新干预措施。”

ENFLONSIA should not be administered to infants with a history of serious hypersensitivity reactions, including anaphylaxis, to any component of ENFLONSIA. See additional Selected Safety Information below.

ENFLONSIA 不应给予对 ENFLONSIA 的任何成分有严重过敏反应史（包括过敏性休克）的婴儿。请参阅以下额外的选定安全信息。

The approval is based on results from the pivotal Phase 2b/3 CLEVER trial (MK-1654-004) evaluating a single dose of ENFLONSIA administered to preterm and full-term infants (birth to 1 year of age). The trial met its primary and key secondary endpoints, as outlined below.

该批准基于关键的 2b/3 期 CLEVER 试验（MK-1654-004）的结果，该试验评估了给予早产儿和足月婴儿（出生至 1 岁）单剂量 ENFLONSIA 的效果。试验达到了其主要终点和关键次要终点，具体如下。

ENFLONSIA demonstrated a reduction in incidence of RSV-associated medically attended lower respiratory infections (MALRI) requiring ≥1 indicator of lower respiratory infection (LRI) or severity compared to placebo through 5 months (primary endpoint) by 60.5% (95% CI: 44.2, 72.0, p<0.001) (incidence rates: ENFLONSIA, 0.026; placebo, 0.065)..

ENFLONSIA在五个月内（主要终点）将与RSV相关的需要≥1个下呼吸道感染（LRI）或严重性指标的医学观察下呼吸道感染（MALRI）发生率降低了60.5%（95%置信区间：44.2, 72.0，p<0.001）（发生率：ENFLONSIA，0.026；安慰剂，0.065）。

ENFLONSIA demonstrated a reduction in RSV-associated hospitalizations through 5 months (key secondary endpoint) by 84.3% (95% CI: 66.7, 92.6, p<0.001) (incidence rates: ENFLONSIA, 0.004; placebo, 0.024), showing increasing efficacy with increasing disease severity.

ENFLONSIA 在5个月内（关键次要终点）将RSV相关住院率降低了84.3%（95% CI：66.7，92.6，p<0.001）（发生率：ENFLONSIA，0.004；安慰剂，0.024），显示出随着疾病严重程度增加而提高的疗效。

The approval is also supported by results from the Phase 3 SMART trial (MK-1654-007) evaluating the safety and efficacy of ENFLONSIA versus palivizumab in infants at increased risk for severe RSV disease.

该批准还得到了 3 期 SMART 试验 (MK-1654-007) 的结果支持，该试验评估了 ENFLONSIA 与帕利珠单抗在严重 RSV 疾病高风险婴儿中的安全性和有效性。

“ENFLONSIA provides an important new preventive option to help protect healthy and at-risk infants born during or entering their first RSV season with the same dose regardless of weight,” said Dr. Dean Y. Li, president, Merck Research Laboratories. “We are committed to ensuring availability of ENFLONSIA in the U.S.

“ENFLONSIA为在呼吸道合胞病毒（RSV）季节出生或进入其第一个RSV季节的健康和有风险的婴儿提供了一种重要的新预防选择，无论体重如何，都使用相同剂量，”默克研究实验室总裁李延年博士表示。“我们致力于确保ENFLONSIA在美国的供应。”

before the start of the upcoming RSV season to help reduce the significant burden of this widespread seasonal infection on families and health care systems.”.

“在即将到来的RSV季节开始之前，帮助减轻这种广泛传播的季节性感染对家庭和医疗系统的重大负担。”

The U.S. Centers for Disease Control and Prevention’s (CDC’s) Advisory Committee on Immunization Practices is expected to meet later this month to discuss and make recommendations for the use of ENFLONSIA in infants. Ordering is anticipated to begin in July, with shipments delivered before the start of the 2025-2026 RSV season..

美国疾病控制与预防中心 (CDC) 的免疫实践咨询委员会预计将于本月晚些时候召开会议，讨论并就ENFLONSIA在婴儿中的使用提出建议。预计订购将在7月开始，并在2025-2026年RSV季节开始前完成发货。

About ENFLONSIA™ (clesrovimab-cfor)

关于ENFLONSIA™（clesrovimab-cfor）

ENFLONSIA (clesrovimab-cfor) is Merck’s extended half-life monoclonal antibody (mAb) indicated for passive immunization for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in newborns and infants who are born during or entering their first RSV season. ENFLONSIA is administered using non-weight-based dosing and is designed to provide direct, rapid and durable protection through 5 months, a typical RSV season.

ENFLONSIA（clesrovimab-cfor）是默克公司开发的长效单克隆抗体（mAb），用于被动免疫，预防在第一个呼吸道合胞病毒（RSV）季节出生或进入该季节的新生儿和婴儿的RSV下呼吸道疾病。ENFLONSIA采用非体重依赖性剂量给药，旨在通过典型的5个月RSV季节提供直接、快速且持久的保护。

For infants born during the RSV season, ENFLONSIA is to be administered starting from birth. For infants born outside of the RSV season, ENFLONSIA should be administered prior to the start of their first RSV season. For infants undergoing cardiac surgery with cardiopulmonary bypass during or entering their first RSV season, an additional 105 mg dose is recommended as soon as the infant is stable after surgery..

对于在RSV季节出生的婴儿，应从出生开始给予ENFLONSIA。对于在RSV季节之外出生的婴儿，应在他们第一个RSV季节开始前给予ENFLONSIA。对于在第一个RSV季节期间或进入第一个RSV季节时接受带心肺旁路的心脏手术的婴儿，建议在手术后婴儿情况稳定时尽快追加105毫克的剂量。

Selected Safety Information for ENFLONSIA

恩氟烷精选安全信息

(clesrovimab-cfor)

（clesrovimab-cfor）

Do not administer ENFLONSIA to infants with a history of serious hypersensitivity reactions, including anaphylaxis, to any component of ENFLONSIA.

请勿对有任何ENFLONSIA成分严重过敏反应史（包括过敏性休克）的婴儿使用ENFLONSIA。

Serious hypersensitivity reactions, including anaphylaxis, have been observed with other human immunoglobulin G1 (IgG1) monoclonal antibodies. If signs or symptoms of a clinically significant hypersensitivity reaction or anaphylaxis occur, initiate appropriate medications and/or supportive therapy.

其他人类免疫球蛋白G1（IgG1）单克隆抗体已观察到严重的超敏反应，包括过敏反应。如果出现具有临床意义的超敏反应或过敏反应的迹象或症状，应开始适当的药物和/或支持治疗。

The most common adverse reactions were injection-site erythema (3.8%), injection-site swelling (2.7%) and rash (2.3%).

最常见的不良反应是注射部位红斑 (3.8%)、注射部位肿胀 (2.7%) 和皮疹 (2.3%)。

About Clinical Trials and Data Supporting U.S. FDA Approval

关于支持美国FDA批准的临床试验和数据

The CLEVER trial (MK-1654-004) (

CLEVER试验（MK-1654-004）（

NCT04767373

NCT04767373

) was a Phase 2b/3, randomized, double-blind, placebo-controlled trial to evaluate the safety and efficacy of ENFLONSIA in early and moderate preterm infants (≥29 to <35 weeks gestational age [GA]) and late preterm and full-term infants (≥35 weeks GA) entering their first RSV season. Participants were randomized 2:1 to receive a single 105 mg dose of ENFLONSIA (N=2,411) or saline placebo (N=1,203) by intramuscular (IM) injection..

) 是一项 IIb/III 期、随机、双盲、安慰剂对照试验，旨在评估 ENFLONSIA 在早期和中度早产儿（≥29 至 <35 周胎龄 [GA]）以及晚期早产儿和足月婴儿（≥35 周 GA）中的安全性和有效性，这些婴儿正处于他们的第一个 RSV 流感季节。参与者按 2:1 的比例随机分配，通过肌肉注射 (IM) 接受单次 105 毫克剂量的 ENFLONSIA（N=2,411）或生理盐水安慰剂（N=1,203）。

The primary endpoint was the incidence of participants with RSV-associated medically attended lower respiratory infection (MALRI) characterized as cough or difficulty breathing and requiring ≥1 indicator of LRI (wheezing, rales/crackles) or severity (chest wall in-drawing/retractions, hypoxemia, tachypnea, dehydration due to respiratory symptoms) from Day 1 through Day 150 (5 months) after dosing.

主要终点是从第1天到第150天（5个月）给药后，出现伴有咳嗽或呼吸困难且需要≥1项下呼吸道感染（LRI）指标（喘息、啰音/爆裂音）或严重程度指标（胸壁内陷/回缩、低氧血症、呼吸急促、因呼吸道症状导致脱水）的RSV相关需医疗护理的下呼吸道感染（MALRI）的参与者发生率。

Medically attended includes all health care provider visits in settings such as outpatient clinic, clinical study site, emergency department, urgent care center and/or hospital. The key secondary endpoint was RSV-associated hospitalization through Day 150 (5 months)..

医学观察包括在门诊诊所、临床研究地点、急诊科、紧急护理中心和/或医院等场所的所有医疗服务提供者访问。关键的次要终点是通过第150天（5个月）的RSV相关住院情况。

The trial demonstrated that the safety profile of ENFLONSIA in infants entering their first RSV season was generally comparable to placebo. The most common adverse reactions were injection-site erythema occurring within 5 days post-dose (ENFLONSIA: 3.8%; placebo: 3.3%), injection-site swelling occurring within 5 days post-dose (ENFLONSIA: 2.7%; placebo: 2.6%) and rash occurring within 14 days post-dose (ENFLONSIA: 2.3%; placebo: 1.9%).

该试验表明，在进入第一个RSV季节的婴儿中，ENFLONSIA的安全性特征总体上与安慰剂相当。最常见的不良反应为：剂量后5天内注射部位红斑（ENFLONSIA：3.8%；安慰剂：3.3%）、剂量后5天内注射部位肿胀（ENFLONSIA：2.7%；安慰剂：2.6%）以及剂量后14天内出现皮疹（ENFLONSIA：2.3%；安慰剂：1.9%）。

Participants were monitored for serious adverse events (SAEs) through the duration of their participation for up to 365 days post-dose. Most (≥97%) of the adverse reactions were toxicity grade 1 (mild) or grade 2 (moderate)..

参与者在整个参与期间被监测了严重不良事件（SAEs），时间最长为接种后365天。大多数（≥97%）的不良反应为1级（轻度）或2级（中度）毒性。

The SMART trial (MK-1654-007) (

SMART试验（MK-1654-007）（

NCT04938830

NCT04938830

) was a Phase 3, randomized, partially-blind, palivizumab-controlled, multi-site trial to evaluate the safety and efficacy of ENFLONSIA in infants at increased risk of severe RSV disease, including early (<29 weeks GA) or moderate preterm infants (≥29 to ≤35 weeks GA) and infants with chronic lung disease of prematurity or congenital heart disease of any GA.

）是一项III期、随机、部分盲法、帕利珠单抗对照、多中心试验，旨在评估ENFLONSIA在严重RSV疾病高风险婴儿中的安全性和有效性，包括早期（<29周胎龄）或中度早产儿（≥29至≤35周胎龄）以及患有早产慢性肺病或任何胎龄的先天性心脏病的婴儿。

Participants were randomized 1:1 to receive ENFLONSIA (N=446) or palivizumab (N=450) by IM injection..

参与者被随机分配1:1接受ENFLONSIA（N=446）或帕利珠单抗（N=450）通过肌肉注射。

Among infants at increased risk of severe RSV disease and entering their first RSV season, the trial demonstrated that the safety profile of ENFLONSIA was generally comparable to palivizumab and consistent with the safety profile of ENFLONSIA in infants in the CLEVER trial. The efficacy of ENFLONSIA in infants at increased risk for severe RSV disease was established by extrapolation of efficacy of ENFLONSIA from the CLEVER trial to the SMART trial based on similar pharmacokinetic exposure.

在严重RSV疾病风险增加且进入第一个RSV季节的婴儿中，试验表明ENFLONSIA的安全性特征总体上与帕利珠单抗相当，并且与CLEVER试验中婴儿使用ENFLONSIA的安全性特征一致。ENFLONSIA在严重RSV疾病高风险婴儿中的疗效是通过将CLEVER试验中ENFLONSIA的疗效外推至SMART试验，并基于相似的药代动力学暴露水平来确定的。

The incidence rates of RSV-associated MALRI requiring ≥1 indicator of LRI or severity and RSV-associated hospitalization were generally comparable between ENFLONSIA (3.6%, 95% CI: 2.0, 6.0 and 1.3%, 95% CI: 0.4, 2.9, respectively) and palivizumab (2.9%, 95% CI: 1.5, 5.2 and 1.5%, 95% CI: 0.5, 3.2, respectively) through Day 150 (5 months)..

ENFLONSIA（3.6%，95% CI：2.0, 6.0 和 1.3%，95% CI：0.4, 2.9）与帕利珠单抗（2.9%，95% CI：1.5, 5.2 和 1.5%，95% CI：0.5, 3.2）在第150天（5个月）时，与RSV相关的MALRI（需要≥1个LRI或严重性指标）和RSV相关住院的发生率总体相当。

In clinical trials, when ENFLONSIA was given concomitantly with routine childhood vaccines, the safety profile of the co-administered regimen was generally comparable to the safety profile when ENFLONSIA and childhood vaccines were administered alone.

在临床试验中，当ENFLONSIA与常规儿童疫苗同时接种时，联合接种方案的安全性特征通常与单独接种ENFLONSIA和儿童疫苗时的安全性特征相当。

About Merck

关于默克

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines.

在默克（在美国和加拿大以外地区称为MSD），我们围绕一个使命团结一致：我们利用前沿科学的力量来拯救和改善全球生命。130多年来，我们通过开发重要的药物和疫苗为人类带来希望。

We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities.

我们立志成为全球首屈一指的研究密集型生物制药公司——今天，我们站在研究的最前沿，提供创新的健康解决方案，推动人类和动物疾病预防与治疗的进步。我们培养多元化和包容性的全球员工队伍，并每天负责任地运营，以确保为所有人和社区创造一个安全、可持续和健康的未来。