FDA panel recommends more research on motavizumab; against approval

The FDA’s Antiviral Drugs Advisory Committee (ADVAC) said more data are needed on MedImmune’s motavizumab regarding the product's safety, efficacy and indications and voted 14-3 against approving the product for marketing.

AstraZeneca's U.S.-based MedImmune developed motavizumab (MEDI-524) as a prophylaxis for lower respiratory tract disease caused by respiratory syncytial virus (RSV).

The panel reviewed one phase-2 and two phase-3 trials that compared motavizumab with palivizumab, (Synagis), which is also designed to prevent RSV.

Results from one of the phase-3 studies demonstrated that motavizumab was noninferior to palivizumab for prevention of RSV-related hospitalizations in high-risk children. Many of the children enrolled in this study, however lived in the Southern Hemisphere, and ADVAC members questioned if these data would hold true for those living in North America.

The panel noted that non-fatal hypersensitivity adverse events were also more prevalent among children receiving motavizumab when compared with those taking palivizumab or placebo in all three trials. MedImmune researchers noted that these negative reactions were mostly mild to moderate in severity and easily resolved on their own or with antihistamine treatment.

Panel members, however, remained cautious, with many noting that the prophylaxis would likely be indicated for use in sicker children than those evaluated in the study. Because of their underlying conditions, those children may sustain more intense adverse reactions to motavizumab, committee members said.

Most panel members agreed that more research into populations for which motavizumab would be best suited for use is needed. They also called for more data on the drug’s effect in larger pediatric populations with more severe RSV-related infections, and further study on adverse events and how they can be treated in the future. “We continue to believe motavizumab offers a meaningful clinical benefit to patients at high risk for a very common and serious illness,” Genevieve Losonsky, MD, vice president, clinical development, infectious disease at MedImmune said in a press release. “We thank the committee for the thoroughness of its review. We will work to address the issues raised by the committee and look forward to continuing to work with the FDA as it completes its review of our application.”– by Melissa Foster

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