motavizumab motavizumab motavizumab (proposed inn, trade name numax) is a humanized monoclonal antibody. it is being investigated by medimmune (today a subsidiary of astrazeneca) for the prevention of respiratory syncytial virus infection in high-risk infants. as of september 2009, it is undergoing phase ii and iii clinical trials. motavizumabmonoclonal antibodytypewhole antibodysourcehumanized (from mouse)targetrsv glycoprotein fclinical datatrade namesnumaxroutes ofadministrationintravenousatc codej06bd02 (who) pharmacokinetic dataprotein bindingnoneidentifierscas number677010-34-3 ndrugbankdb06310 ychemspidernoneunii50y163lk8qkeggd06621 ychemical and physical dataformulac6476h10014n1706o2008s48molar mass145438.16 g·mol−1 ny (what is this?) (verify) in june 2010, the fda antiviral drugs advisory committee declined to endorse medimmune's request for licensure of motavizumab in a 14 to 3 decision. the members of that panel cited several reasons for the decision, and many were concerned that "we're not looking at a product that has evidence of superiority in terms of efficacy" when compared to the already available monoclonal antibody palivizumab. in december 2010, astrazeneca in a stock market statement stated that it would be writing down $445m (£286m) after discontinuing a key development programme for motavizumab. the company stated that it would no longer develop motavizumab for the prevention of respiratory syncytial virus (rsv), and as a result was withdrawing its licence application to the us food and drug administration. it added that it would continue to develop motavizumab for other treatments of rsv.