Monoclonal Antibodies Linked to Reduced RSV Burden in Young Kids

Prophylactic use of three monoclonal antibodies was associated with substantial reductions in respiratory syncytial virus (RSV)-related infections and hospitalizations in children under 5, a systematic review and meta-analysis showed.

Across 14 randomized controlled trials involving over 18,000 high-risk children, moderate- to high-certainty evidence showed that nirsevimab, palivizumab, and motavizumab were associated with significant reductions in RSV-related infections and hospitalizations per 1,000 participants compared with placebo, reported Long Ge, PhD, of Lanzhou University in Lanzhou City, China, and colleagues:

• Nirsevimab: -123 (95% CI -138 to -100) and -54 (95% CI -64 to -38)
• Palivizumab: -108 (95% CI -127 to -82) and -39 (95% CI -48 to -28)
• Motavizumab: -136 (95% CI -146 to -125) and -48 (95% CI -58 to -33)

Moderate-certainty evidence showed that intensive care unit admissions per 1,000 participants were significantly lower with motavizumab (-8, 95% CI -9 to -4) and palivizumab (-5, 95% CI -7 to 0), as was supplemental oxygen use per 1,000 participants (-59 [95% CI -63 to -54] and -55 [95% CI -61 to -41], respectively), while nirsevimab was associated with significantly reduced supplemental oxygen use per 1,000 participants (-59, 95% CI -65 to -40), they noted in JAMA Network Open.

No significant differences were found in all-cause mortality or drug-related adverse events.

While four monoclonal antibodies were included in the meta-analysis, suptavumab showed no significant benefits.

“The World Health Organization published documents in 2021 that already encouraged the development of preventive interventions for RSV,” Ge and team wrote. “Palivizumab is currently the most widely used prophylaxis for preventing RSV disease in infants.”

“Although the efficacy of palivizumab has been proved, it is not available in some countries, such as China,” they noted. “Meanwhile, the high price of palivizumab imposes a substantial economic burden on low- and middle-income families. Therefore, new monoclonal antibodies (mAbs) have been developed, such as nirsevimab, which could protect infants from RSV-related infection and hospitalization during an entire RSV season with a single dose.”

“However, the relative efficacy and safety of different mAbs have not been compared comprehensively,” they added, which led them to conduct their study.

Amesh Adalja, MD, of Johns Hopkins Bloomberg School of Public Health in Baltimore, told MedPage Today that “the findings are not surprising. We’ve seen data on the efficacy of monoclonal antibodies in the prevention of RSV and high-risk individuals for some time. We have an approved product here in the United States, as well as a new approved product in the European Union, which will likely soon be approved in the United States.”

“The new monoclonal antibody coupled with new vaccines will hopefully have a major impact on RSV in future seasons, making it much more manageable and decreasing its burden,” he said.

For this review and meta-analysis, Ge and colleagues searched PubMed, Embase, CENTRAL, and ClinicalTrials.gov for relevant trials from database inception to March 2022. They included 14 randomized controlled trials involving 18,042 children under 5 years of age. Median age at study entry was 3.9 months, the median proportion of boys was 52.4%, and most were white. About 67% were born prematurely, 8.1% had chronic lung disease, and 14% had congenital heart disease.

Ge and team noted that some comparison groups lacked direct evidence and could only be assessed through indirect comparisons.

In addition, some comparisons were rated as low certainty of evidence, mainly due to risk of bias and imprecision because of lacking evidence or a wide credible interval, they said, and future studies are needed to address these issues.