Visterra Doses First Patient in Phase 2a Trial for VIS410, its Monoclonal Antibody in Development for the Treatment of Hospitalized Patients with Influenza A

Cambridge, MA – January 11, 2017 – Visterra, Inc., a clinical-stage biopharmaceutical company, today announced that the first patient was dosed in a Phase 2a clinical trial of VIS410, a monoclonal antibody in development for the treatment of hospitalized patients with influenza A, regardless of the viral strain.

This global Phase 2a clinical trial is being conducted in approximately 150 ambulatory patients diagnosed with influenza A. Patients in the Phase 2a clinical trial will be randomized into one of three arms to receive either 2000 mg of VIS410, 4000 mg of VIS410, or placebo. The primary endpoint of the study is safety and tolerability and secondary endpoints include clinical symptoms of influenza, virology and pharmacokinetics of VIS410.

This project has been funded in whole or in part with Federal funds from the Department of Health and Human Services; Office of the Assistant Secretary for Preparedness and Response; Biomedical Advanced Research and Development Authority (BARDA), under Contract No. HHSO100201500018C.

About VIS410

VIS410 is a monoclonal antibody designed and engineered to target all known strains of influenza A and is being developed to treat hospitalized patients with influenza A. VIS410 is directed against a specific epitope, which we refer to as a Hierotope, on hemagglutinin, which is a surface protein of influenza viruses used for binding and entry into cells. VIS410 is designed to prevent fusion of the influenza virus with host cell membranes by binding to hemagglutinin and thereby terminating the viral replication cycle.

About Influenza

Influenza is an infectious disease that causes illness in humans worldwide with symptoms that range in severity from mild to life-threatening. The majority of seasonal influenza infections result in mild illness; however, some infections result in severe disease, which can involve rapidly progressive pneumonia, respiratory failure and, in some cases, death. Severe disease is more commonly observed in high-risk groups, including infants, pregnant women, the elderly, patients with underlying medical conditions, and patients with disease- or treatment-related immunosuppression. According to the CDC, approximately 35 million people suffer from influenza infections in the United States each year, resulting in as many as 400,000 hospitalizations and as many as 49,000 deaths. The World Health Organization reports that globally there are as many as five million severe influenza cases annually, leading to as many as 500,000 deaths. In addition to seasonal infections, epidemics that spread across countries and continents, or pandemics, are caused by influenza strains that have a high rate of humanto-human transmission and, if the strain causes severe disease, can lead to a high mortality rate.

About Visterra

Visterra is a clinical-stage biopharmaceutical company focused on applying its novel Hierotope® platform to identify unique disease targets and to design and engineer precision antibody-based biological medicines for infectious and non-infectious diseases. Visterra believes that its platform enables Visterra to address the significant unmet need for effective therapies to prevent and treat infectious diseases caused by organisms that have a high degree of diversity among strains, frequent mutations and a high prevalence of treatment resistance. Visterra’s platform also enables the design and engineering of antibody-based biological product candidates for the treatment of non-infectious diseases that are not being adequately addressed with conventional treatment approaches. Visterra’s lead product candidate, VIS410, is a monoclonal antibody in development for the treatment of hospitalized patients with influenza A, regardless of the viral strain. The company’s second product candidate, VIS513, is a monoclonal antibody in development for the treatment of Dengue, and its third product candidate, VIS649, is a monoclonal antibody in development for the treatment of IgA Nephropathy. Visterra was founded on the research into the fundamentals of viral evolution and epitope characterization by its scientific founder, Dr. Ram Sasisekharan at MIT. For more information, please visit www.visterrainc.com.

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