Nasal Influenza Vaccine Shows Promise for Cross-immunity

Jorma Hinkula, Director of Immunology, Eurocine Vaccines AB, in a presentation at the 2010 World Vaccine Congress in Lyon, France, discussed results from a clinical trial involving the Immunose nasal influenza vaccine. He told the audience that in a phase I/II study, Eurocine Vaccines’ nasal influenza vaccine, Immunose FLU, demonstrated “an immunological response both systemically, in serum, and locally, in the nasal mucosa.” The vaccine increased the amount of antibodies in the nasal mucosa, compared to the injected reference vaccine. Hinkula said that the results also indicated cross immunity.

For the study, 154 healthy volunteers were randomized into six dose groups of varying combinations of the Endocine adjuvant and antigen, or into three reference groups, one of which received a commercially available intramuscular influenza vaccine. The primary endpoints of the study were clinical safety and tolerability. The study showed that Immunose FLU produced a greater increase in the amount of antibodies in the nasal mucosa compared to an injected commercial influenza vaccine. Analyses of antibodies in nasal mucosa and serum indicated cross immunity, which means that the vaccine provides an immune response to more virus strains than those included in the vaccine.

“Immunose FLU shows a broader immune response compared to the intramuscular reference,” Hinkula said. He also noted that “Cross immunity may give protection against a broader range of virus strains rather than only against the strains in the vaccine, a feature with enormous potential, for example, in an urgent pandemic situation.”

Reported side effects were mostly mild and consisted of transient irritation of the nose and pharynx. The vaccine displayed a high degree of safety and thus met the primary endpoint. None of the participants had to discontinue the study due to side effects. “Safety is always a top priority for a prophylactic vaccine. In this study the nasal adjuvant Endocine that opens for nasal vaccination with an inactivated influenza vaccine shows the potential to meet that requirement. As the adjuvant consists of endogenous components, an attractive safety profile could be expected.” Hinkula said.

Altogether, Immunose FLU demonstrated an immunological response, including HAI (hemagglutination inhibition titer) levels, which confirms the development approach chosen by Eurocine Vaccines. The clear immune response in the nasal mucosa, at the entry point for an influenza infection, supports the view that there is the potential to stop the infection before it enters the body. “This implies a huge benefit in vaccine development,” said Hinkula. “Why invite the influenza virus to begin the party inside the fortress, when we simply can close the gates by nasal vaccination and conquer the virus before entering?”

Hinkula said that the company plans to continue the clinical development program, including phase III, in cooperation with a prospective partner.