Utilization and efficacy of palivizumab for children with Down syndrome.

BACKGROUND

Palivizumab is a prophylactic drug used for severe respiratory syncytial virus (RSV) infection in young children with high-risk factors, such as prematurity and congenital heart diseases. Although Japan expanded the use of palivizumab for Down syndrome (DS) in 2013 regardless of additional high-risk factors, there is not enough evidence to support its use. We analyzed health insurance claim data from the JMDC (Tokyo, Japan) to investigate the prescription pattern and efficacy of palivizumab in children with DS.

METHODS

We enrolled children of ≤24 months of age with DS at the start of the RSV epidemic season (2007-2015). We compared the risk of RSV-related admission with and without palivizumab prophylaxis using mixed effects logistic regression models accounting for patient-level clustering.

RESULTS

Of 632 children, 30% (81/268) and 83% (303/364) received palivizumab before and after the expanded program (2007-2012 and 2013-2015), respectively. Among children with DS but without additional high-risk factors (n = 135), palivizumab use surged from 0% (0/62) to 73% (53/73). In the whole study population, RSV-related hospitalization occurred in 4.2% (16/384) patients with prophylaxis and 6.0% (15/248) patients without prophylaxis. The multivariate analysis revealed that palivizumab was associated with reduced RSV-related hospitalization (odds ratio: 0.41, 95% confidence interval: 0.18-0.92, P = 0.03).

CONCLUSIONS

Virtually all children with DS in Japan have now received palivizumab, the use of which was associated with a reduction in RSV-related hospitalization in DS. Further evidence is required to clarify whether palivizumab prophylaxis should be risk-tailored or universal for DS.