Positive Results From LigoCyte's Norovirus Vaccine Challenge Study Presented at IDSA Annual Meeting

BOZEMAN, Mont., Oct. 25 /PRNewswire/ -- LigoCyte Pharmaceuticals, Inc., a private, clinical-stage biopharmaceuticals company developing innovative vaccine products, today announced positive results from a Phase I/II challenge study of its norovirus virus-like particle (VLP) vaccine candidate. Baylor College of Medicine's Robert Atmar, M.D., 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.

"We are extremely pleased with the opportunity to share the important results from this carefully designed proof-of-concept, multi-center challenge study. Challenge studies are rigorous tests and we have established for the first time that immunized subjects can reduce their risk of norovirus illness by receiving a vaccine," said Donald P. Beeman, Chief Executive Officer. "The study data are very encouraging, indicating statistically significant reductions in clinical norovirus illness, infection, and severity of illness in subjects who received vaccine compared to those who received placebo."

In his presentation, entitled "Efficacy of An Intranasal (IN) Norovirus (NoV) Vaccine to Prevent Acute Gastroenteritis (AGE) Following Experimental Live GI.1 NoV Challenge," Dr. 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 percent efficacy against any norovirus illness, including mild illness, (p=0.006) and 26 percent efficacy against norovirus infection (p=0.046). In the 77 adults who completed the trial as per its original protocol, vaccination decreased the incidence of AGE due to norovirus from 69.2 percent to 36.8 percent and the incidence of norovirus infection from 82.1 percent to 60.5 percent. The severity of illness was also significantly reduced in those vaccinated within the trial (p=0.011).

"At LigoCyte, we are focused on developing a vaccine that has the potential to help address the critical unmet medical need resulting from the burden of norovirus illness in both developed and developing countries," added Mr. Beeman.

Additional information on LigoCyte's norovirus vaccine program was presented last week at the Fourth International Conference on Calicivirus Meeting in Santa Cruz, Chile. In addition, a poster by LigoCyte's Chief Scientific Officer Robert Bargatze, Ph.D., has been accepted for presentation at the Keystone Symposia on Immunological Mechanisms of Vaccination to take place next week in Seattle, Washington.

About Norovirus Infection

Norovirus infection, well known as "the stomach flu," is one of the most common causes of AGE, afflicting nearly 23 million Americans annually and an important contributor to gastrointestinal disease worldwide. Norovirus infection is characterized by the acute onset of nausea, vomiting, abdominal cramps, diarrhea, and occasionally fever. Noroviruses are highly infective and easily transmitted. Epidemic outbreaks occur in community environments, particularly hospitals, hotels, schools, day care facilities and nursing homes, with mounting socioeconomic cost to families, the health care system and businesses. Military units are significantly affected when the virus strikes, as outbreaks impact combat readiness. Severe clinical outcomes are associated with at-risk populations such as immunocompromised individuals where complications caused by infection can disrupt primary treatment regimens and even lead to death.

About the Phase I/II Norovirus Vaccine Study

The Phase I/II randomized, double blind, multi-center, placebo-controlled safety and efficacy study was designed to evaluate the norovirus monovalent GI.1 VLP vaccine versus placebo in approximately 90 healthy adult volunteers between the ages of 18 and 50 years. The study consisted of two stages: the Vaccination Stage with post-vaccination follow-up, followed by the Challenge Stage with post-challenge follow-up. Subjects received a two-dose intranasal regimen of either the vaccine or placebo on Days 0 and 21 and were evaluated for vaccine safety and immune responses. On or after Study Day 42, subjects were admitted to an inpatient nursing unit, challenged with live norovirus, held in the unit for at least four days following challenge and then followed for post-challenge safety and efficacy with multiple clinical assessments and collection of stool specimens. The study was conducted at Baylor College of Medicine, the University of Cincinnati and Cincinnati Children's Hospital Medical Center, the Johns Hopkins School of Medicine and SNBL CPC, Inc., a clinical research organization in Baltimore, MD.

About LigoCyte's Intranasal Norovirus Vaccine Candidate

LigoCyte's intranasal norovirus vaccine is a dry powder formulation containing virus-like particle (VLP) antigens representing the live virus while 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 (NYSE: GSK), and the nasal vaccine incorporates chitosan. This application of chitosan (ChiSys®) has been licensed from Archimedes Development Ltd.(1)

A clinical study of an intramuscular bivalent formulation of LigoCyte's norovirus vaccine is ongoing.

About LigoCyte

LigoCyte is a private, clinical-stage biopharmaceutical company focused on developing novel vaccines for gastrointestinal and respiratory indications. LigoCyte's expertise in virus-like particle technology supports a pipeline of enhanced product candidates, including vaccines against norovirus, influenza and respiratory syncytial virus. LigoCyte has funded its product development efforts through a mix of private investment as well as grants and contracts administered through the National Institutes of Health and the U.S. Department of Defense, including a recent $3.6 million commitment from the agency. LigoCyte's investors include Forward Ventures, JAFCO, Novartis Venture Fund, Fidelity Biosciences, MedImmune Ventures, Athenian Venture Partners and MC Life Sciences Ventures (Mitsubishi International Corporation). The company closed its most recent financing in October 2010 from its existing venture investors. GlaxoSmithKline is also a shareholder of the company. For additional information on LigoCyte, please visit www.ligocyte.com.

(1) ChiSys is a trademark of Archimedes Development Ltd., and is registered as a CTM, as a U.S. Registered Trademark and in certain other jurisdictions.

SOURCE LigoCyte Pharmaceuticals, Inc.