New antibody-based prevention and treatment options for influenza.

The antigenic diversity of human influenza viruses represents a challenge to the development of vaccines with durable immune protection. In addition, small molecule anti-influenza viral drugs can bring clinical relief to influenza patients but the emergence of drug resistant viruses can rapidly limit the effectiveness of such drugs. In the past decade, a number of human monoclonal antibodies have been described that can bind to and neutralize a broad range of influenza A and B viruses. Most of these monoclonal antibodies are directed against the viral hemagglutinin (HA) stalk and some have now been evaluated in early to mid-stage clinical trials. An important conclusion from these clinical studies is that hemagglutinin stalk-specific antibodies are safe and can reduce influenza symptoms. In addition, examples of bi- and multi-specific anti-influenza antibodies are discussed, although such antibodies have not yet progressed into clinical testing. In the future, antibody-based therapies might become part of our arsenal to prevent and treat influenza.