• Provides growth capital to advance pneumococcal  vaccine to clinic and beyond
• Preeminent executive vaccinologist, Moncef  Slaoui, appointed Board Chairman
• Strategic alignment established with Lonza  Pharma & Biotech to create end-to-end supply chain

Foster City, CA, June 7, 2018 – SutroVax, a biopharmaceutical company dedicated  to the delivery of best-in-class conjugate vaccines and novel complex antigen-based  vaccines to prevent serious infectious diseases, today announced the closing of an upsized $85 million Series C financing led by new investor TPG Growth, the global  middle market and growth equity platform of TPG. Other new investors include Medicxi  and Foresite Capital.  All of SutroVax's existing institutional investors,  including Abingworth, Longitude Capital, Frazier Health Care Partners, Pivotal  bioVenture Partners, Roche Venture Fund, and CTI Life Sciences Fund also  participated in the financing.

Proceeds of the financing will be used to  advance the company's potentially best-in-class broad-spectrum pneumococcal  conjugate vaccine (PCV) candidate through mid-stage clinical development and  continue to expand its pipeline of novel vaccines.  SutroVax's PCV is designed  to prevent invasive pneumococcal disease caused by Streptococcus  pneumoniae and is uniquely positioned to significantly expand  protection against circulating strains of pneumococcus.

SutroVax is also announcing a strategic contractual  relationship with Lonza Pharma & Biotech, one of the world's leading  contract manufacturers of complex biologics, to manufacture its PCV program via  an end-to-end supply relationship. The parties have established strong  alignment on process and conjugation development, as well as microbial  manufacturing scale-up for drug substance at Lonza's Visp, Switzerland, site.  This close technical collaboration between SutroVax and Lonza will support the  successful delivery of this potentially best-in-class vaccine to the clinic as  efficiently as possible and to streamline its advance to the market.

"Assembling growth capital with world-class  manufacturing capabilities enhances our ability to bring to market a better  version of the best-selling vaccine of all time and provides the building  blocks for the company to mature into a fully integrated vaccine company," said  Grant Pickering, CEO and Founder of SutroVax. "Furthermore, we are delighted to  welcome Dr. Moncef Slaoui to the Chairman role, where his experience building  GSK into the world's leading vaccine company will serve us well as we work to  deliver on the vast potential of this opportunity. We also want to thank Kurt  von Emster for his Chairmanship over the past three years, while the company  delivered on its initial vision and fortified its position raising over $170M  in equity capital."
 
In conjunction with the closing of the financing,  Heath Lukatch, Ph.D., Partner at TPG, will  join the SutroVax Board of Directors and Francesco de Rubertis, Ph.D., Founding  Partner of Medicxi, will join as a Board Observer.

"SutroVax's unique  technology has the potential to disrupt the conjugated vaccine space," said  Lukatch. "The company's ability to create high-valency vaccines with strong  immunogenicity is what attracted TPG Growth to this deal. We believe that  SutroVax's PCV program is well positioned to dramatically improve on the current  standard of care for prevention of pneumococcal disease, offering the  opportunity to replace existing pneumococcal vaccines used in both infants and  adults."

Moncef Slaoui,  Ph.D. commented, "After almost a year as an independent board member, I have  come to fully appreciate the huge potential of SutroVax's PCV program. I am  thrilled to take on the Chairman role and I am confident we will advance this  program to a clear clinical proof of concept and ultimately make it available  for broad  use."

"The marriage of  this state-of-the art vaccine with broad organizational alignment between our  two companies is a perfect fit with our strategy of being one of the world's  leading, integrated value-added solution providers," said Karen Fallen, VP,  Business Unit Head Clinical Development & Manufacturing. "Lonza's expertise  in complex molecule development, microbial production and conjugation capabilities,  along with our commercial production presence, will support delivery of this  important vaccine for SutroVax at this critical phase in the lifecycle of their  company."

About  Pneumococcal Disease and the Pneumococcal Vaccine Market

Pneumococcal disease is an infection caused by  Streptococcus pneumoniae. This infection can cause a wide range of serious  illnesses including pneumonia, meningitis and blood stream infection as well as  ear and sinus infections. According to the Centers for Disease Control and  Prevention (CDC), an estimated 900,000 Americans suffer from pneumococcal  pneumonia each year and up to 400,000 hospitalizations occur in the US.  In addition, about 18,000 older adults die  each year from pneumococcal disease in the U.S. The market-leading vaccine is a  13-valent PCV, Prevnar 13®, that has worldwide sales of  approximately $6 billion annually, yet does not protect against a significant  number of circulating strains of pneumococcus causing invasive disease in  adults and children. In the U.S., the CDC's Advisory Committee on Immunization  Practices (ACIP) recommends all children aged two months to five years and  immunocompromised children aged six years and older be vaccinated with Prevnar  13.  In addition, the ACIP recommends all  adults aged 65 years and older and immunocompromised adults aged 19 years and  older be vaccinated with Prevnar 13 and Pneumovax®, a 23-valent  non-conjugate vaccine with over $800 million in annual sales.

About SutroVax
 
  SutroVax is an independent vaccine platform  and development company whose mission is to deliver best-in-class conjugate  vaccines and novel complex antigen-based vaccines to prevent serious infectious  diseases. SutroVax conjugate vaccines are developed utilizing the Company's  exclusive rights to Sutro Biopharma's Xpress CF™ Platform, a cell-free protein  synthesis technology. The platform represents a major advancement over  conventional conjugate vaccine production methods, by enabling precise and  consistent conjugation of antigens to site-specific locations on a protein  carrier that do not impede T-cell help resulting in higher-potency conjugates.  SutroVax is utilizing these more potent conjugates to develop, among other  programs, a broader-spectrum PCV product. For more information, visit www.sutrovax.com.

About TPG Growth

TPG  Growth is the middle market and growth equity investment platform of TPG,  the global alternative asset firm. With approximately $13.5 billion of  assets under management, TPG Growth targets investments in a broad range  of industries and geographies. TPG Growth has the deep sector  knowledge, operational resources, and global experience to drive value  creation, and help companies reach their full potential. The firm is backed  by the resources of TPG, which has more than $82 billion of assets under  management. For more information, visit www.tpg.com.

About Medicxi

Medicxi's  mission is to invest across the full healthcare continuum. Medicxi's team has  been investing in life sciences for over 20 years and was established by the  former Index Ventures life sciences team. Medicxi manages the legacy life  science portfolio of Index Ventures as well as the new funds launched as  Medicxi, Medicxi Ventures 1 (MV1) and Medicxi Growth 1 (MG1) focusing on  early-stage and late-stage investments in life sciences. GSK, Johnson &  Johnson and Novartis, three of the world's largest pharmaceutical companies  back Medicxi along with Verily, an Alphabet company. For more information,  visit www.medicxi.com.

About Foresite  Capital

Foresite Capital is a multi-stage healthcare  and life sciences investment firm that applies rigorous scientific and  data-driven approaches to investment analysis. The firm has $2 billion under  management. Foresite Capital takes a collaborative approach to investing with  its portfolio companies by providing a multidisciplinary team of scientists,  engineers, analysts, and clinicians who understand the unique business models  in healthcare in addition to capital. The company aims to address areas of  great unmet clinical need over the long term by funding promising healthcare  and life sciences businesses at all stages of their life cycles. Its portfolio  also emphasizes companies that are employing the tools of data science and  machine intelligence in healthcare. For more information, visit www.foresitecapital.com.

About Lonza
 
Lonza  is one of the world's leading and most-trusted suppliers to the pharmaceutical,  biotech and specialty ingredients markets. As an integrated solutions provider,  Lonza is boosting its value creation along and beyond the healthcare continuum  with a strong focus on patient healthcare, consumer preventive healthcare and  consumer's healthy environment. Lonza harnesses science and technology to  create products that support safer and healthier living and that enhance the  overall quality of life. With the recent Capsugel acquisition, Lonza now offers  products and services from the custom development and manufacturing of active  pharmaceutical ingredients to innovative dosage forms for the pharma and  consumer health and nutrition industries. Benefiting from its regulatory  expertise, Lonza is able to transfer its know-how from pharma to hygiene and  fast-moving consumer goods all the way to coatings and composites and the  preservation and protection of agricultural goods and other natural resources.  Founded in 1897 in the Swiss Alps, Lonza today is a well-respected global  company with more than 100 sites and offices and approximately 14,500 full-time  employees worldwide. The company generated sales of CHF 5.1 billion in 2017  with a CORE EBITDA of CHF 1.3 billion. For more information, visit www.lonza.com.

Contact: 
Julie Rathbun
Rathbun Communications
206-769-9219
julie@rathbuncomm.com