Adenovirus vector containing RSV pre-F induces neutralizing antibodies

Sadoff J, De Paepe E, DeVincenzo J, Gymnopoulou E, Menten J, Murray B, Bastian AR, Vandebosch A, Haazen W, Noulin N, Comeaux C, Heijnen E, Eze K, Gilbert A, Lambkin-Williams R, Schuitemaker H, Callendret B

Janssen Pharmaceuticals has shown that a single intramuscular injection with an adenovector (Ad26) -based RSV vaccine is highly immunogenic and able to induce a six-fold increase in RSV A2 neutralizing antibody titers. Viral replication upon RSV A challenge at day 28 after immunization was reduced substantially in vaccinees, although infection was not completely prevented. Similarly, symptom scores were largely reduced upon challenge with RSV A in vaccinated volunteers. However, side effects were seen more often in vaccinees as compared to placebo recipients, which requires further study. No severe side effects were observed. This study shows that an adenovector can be used to elicit prefusion immunity against RSV when containing the RSV-F gene encoding for the protein stabilized in the prefusion conformation. Further field studies are expected to demonstrate efficacy in relevant high risk populations.