Vaccines may be available for pneumococcal infections, but none of them, including the widely used Prevnar 13, can cover all strains. SutroVax is one of the startups trying to solve that problem, and today raised $64 million to test its approach in humans.
New investors Frazier Healthcare Partners and Pivotal bioVenture Partners led the Series B financing round for Foster City, CA-based SutroVax. Also participating in the round were earlier investors Abingworth, Longitude Capital, Roche Venture Fund, and CTI Life Sciences Fund. In addition to the $60 million Series B investment, SutroVax says the earlier investors are also putting another $4 million into the company.
SutroVax is a spinout of South San Francisco-based Sutro Biopharma, one of several companies to specialize in antibody-drug conjugates, cancer therapies that link monoclonal antibodies to cancer-killing chemicals. In 2014, Celgene (NASDAQ: CELG) nabbed an option to buy Sutro outright expanding what had already been a broad alliance to develop ADC’s for cancer. The following year, SutroVax, hoping to apply a similar conjugation technique to vaccines, raised a $22 million Series A to fund the effort.
SutroVax pairs an antigen—a piece of a bacterial or viral protein that prompts an immune response—with another protein called a protein carrier. This protein carrier is intended to boost the body’s immune response. Pneumococcal disease, caused by Streptococcus pneumonia bacteria, is SutroVax’s first target.
Pneumococcal disease can lead to infections in the lungs, the blood, and the brain. Pneumococcal pneumonia is the most common form of the disease, affecting an estimated 900,000 Americans annually, according to the Centers for Disease Control and Prevention. The disease kills 5 to 7 percent of those patients, the CDC says.
Conjugate vaccines are already available to prevent these infections. The Pfizer (NYSE: PFE) vaccine Prevnar 13 was developed to prevent disease caused by 13 Streptococcus pneumonia strains and it generates blockbuster sales for the drugmaker. But SutroVax claims its technology can be develop more potent vaccine conjugates that address a broader spectrum of strains that cause the disease. It’s not alone in that quest. Another small startup backed by the Bill & Melinda Gates Foundation and aligned with Astellas Pharma, Affinivax, has similar plans.
So far, SutroVax has tested its approach only in animals. The funding will help SutroVax start test in humans, though the company didn’t say when those trials would begin. The capital will also support SutroVax’s research efforts in other diseases. The company did not specify which other diseases it would target.