In addition, the trial showed a 71% reduction in the incidence of RSV-specific lower respiratory infections (LRIs) requiring outpatient management (9.5% in placebo group and 2.8 percent in the motavizumab group), which was a secondary endpoint.
Motavizumab is an investigational monoclonal antibody (MAb) being evaluated for its potential to prevent serious disease caused by respiratory syncytial virus (RSV) in high-risk pediatric patients. This phase III trial involved 1,410 full-term infants less than six months of age in two Native American populations. In previous medical studies these populations were shown to have high rates of hospitalization due to RSV.
The randomized, double-blind study was designed to compare monthly intramuscular injections of motavizumab against placebo. After an interim analysis conducted by an independent data safety monitoring committee, the study was unblinded early due to statistical evidence demonstrating that motavizumab reduced RSV hospitalizations and LRIs requiring outpatient medical management within this population.
Motavizumab was well tolerated in these Native American infants, with an overall incidence and severity of adverse events that were similar between the motavizumab and the placebo groups. The mortality rates were not statistically different between groups and were not considered to be related to the study drug. As was suggested in the pivotal phase III trial conducted in high-risk, preterm infants, rates of hypersensitivity related skin rashes within two days of dosing were seen in about 1% of treated children in the motavizumab group.