Visterra, a clinical-stage biotechnology company that uses its novel Hierotope platform to identify unique disease targets and to design and engineer precision antibody-based biological medicines against such targets that are not adequately addressed with conventional approaches, today announced that it has completed a Series C financing round raising a total of $46.7 million, including a new extension totaling $23.6 million. The company raised an initial $23.1 million in June 2016. The extension of the Series C supports Visterra's focus on its two lead product candidates, VIS410 and VIS649, as well as further leveraging of its Hierotope platform, including ViStar antibody Fc engineering capabilities.

The Series C financing round included existing investors - the Bill & Melinda Gates Foundation, MRL Ventures Fund, Vertex Venture Holdings Ltd., Polaris Partners, Flagship Pioneering, Omega Funds, Cycad Group, Alexandria Venture Investments - and new investors, Serum Institute of India Pvt. Ltd., CTI Life Sciences and Allegheny Financial Group.

"We are grateful for the funding and support from high-quality new and existing investors, which recognizes the versatility and unique potential of our novel Hierotope platform and supports the advancement of Visterra's product pipeline," said Brian J. G. Pereira, M.D., President and CEO of Visterra. "We look forward to several key milestones over the next 18 months, including top-line results from our VIS410 Phase 2a clinical trial in ambulatory patients with influenza A in early 2018 and the initiation of our VIS410 Phase 2b clinical trial in hospitalized patients with influenza A in early 2018, as well as the initiation of clinical trials for both VIS649, our IgA nephropathy product candidate, and VIS513, our antibody for the treatment of dengue, currently being developed by our partner, the Serum Institute of India."

Dr. Pereira also commented, "Our Hierotope platform has been very productive in generating a range of promising therapeutic antibodies beyond VIS410, VIS513 and VIS649. As we continue to apply and further enhance our Hierotope platform, including our novel ViStar antibody Fc engineering capabilities, we will consider collaborations with strategic partners relating to these capabilities and for select assets generated from our platform."

A majority of the proceeds from the Series C financing have and will be used to prepare for a planned Phase 2b clinical trial for Visterra's lead product candidate, VIS410, an antibody in development for the treatment of hospitalized patients with influenza A, regardless of the viral strain, and to advance VIS649, an antibody in development for the treatment of IgA nephropathy that has demonstrated promising results in animal models, to a Phase 1 clinical trial. In addition, a portion of the proceeds will be used to further develop the company's ViStar antibody Fc engineering capabilities, which are focused on developing novel modifications to the Fc region of an antibody to enhance half-life and improve effector function.

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 against such targets that are not adequately addressed with conventional approaches. These targets include infectious organisms such as viruses, bacteria and fungi, which have a high degree of diversity among strains with frequent mutations. Visterra's technology is also uniquely capable of engineering biological medicines that selectively modify the activity of endogenous targets that have limited surface area, are hard to access, have dynamic structures, and/or are similar to other proteins in the body that should be avoided. Visterra's lead product candidate, VIS410, is a monoclonal antibody in development as a single-dose administration for the treatment of hospitalized patients with influenza A, regardless of the viral strain. The company's other product candidates are VIS513, a monoclonal antibody in development as a single-dose administration for the treatment of dengue, VIS649, a monoclonal antibody in development for the treatment of IgA nephropathy, and VIS705, an antibody-drug conjugate being developed as a single-dose curative therapy, engineered to kill all strains of the deadly Pseudomonas aeruginosa bacteria, including potentially multi-drug resistant strains. In addition, Visterra has applied its Hierotope platform to develop novel modifications to the Fc region of an antibody, to enhance half-life by as much as ten-fold while maintaining and often improving effector function. These capabilities, called ViStar™ antibody Fc engineering, support the development of long-acting monoclonal antibodies for the extended protection in infectious diseases and less frequent administration in chronic diseases. For more information, visit www.visterrainc.com.