LigoCyte Shows Positive Results from its Norovirus Vaccine Challenge Study

LigoCyte Pharmaceuticals, Inc. (Bozeman, MN) has announced positive results from a Phase 1–2 challenge study of its norovirus virus-like particle (VLP) vaccine candidate. Baylor College of Medicine’s Robert Atmar, MD, the study's principal investigator, shared data from the trial via an oral presentation at the Infectious Diseases Society of America (IDSA) 2010 Annual Meeting on October 23 in Vancouver, British Columbia.

In his presentation, entitled “Efficacy of An Intranasal (IN) Norovirus (NoV) Vaccine to Prevent Acute Gastroenteritis (AGE) Following Experimental Live GI.1 NoV Challenge,” Atmar described the challenge study in which 84 adults completed the challenge after receiving two doses of the vaccine or placebo. The vaccine was generally well tolerated, and demonstrated 47% efficacy against any norovirus illness, including mild illness, (p = 0.006) and 26% efficacy against norovirus infection (p = 0.046). In the 77 adults who completed the trial per its original protocol, vaccination decreased the incidence of AGE caused by norovirus from 69.2% to 36.8%, and the incidence of norovirus infection from 82.1% to 60.5%. The severity of illness also was significantly reduced in those vaccinated in the trial (p = 0.011).

LigoCyte's intranasal norovirus vaccine is a dry powder formulation containing VLP antigens representing the live virus but lacking the ability to reproduce or cause illness. VLPs mimic the natural virus by preserving the authentic structure of the viral capsid (the shell of protein that protects the nucleic acid of a virus). LigoCyte's vaccine formulation also includes the adjuvant Monophosphoryl Lipid A, provided under license from GlaxoSmithKline, and the nasal vaccine incorporates chitosan.