Dynavax Announces Upcoming Data Presentations for Three TLR9 Agonist Programs at the 2017 American Association for Cancer Research Annual Meeting

BERKELEY, CA--(Marketwired - March 20, 2017) - Dynavax Technologies Corporation (NASDAQ: DVAX) announced today that it will be presenting data on three programs based on stimulation of the immune response using Toll-Like Receptor 9 (TLR9) agonists at the 2017 American Association for Cancer Research Annual Meeting in Washington, D.C. from April 1-5, 2017.

Dynavax is presenting data which summarizes the clinical responses and biomarker assessments from an ongoing Phase 1b/2 study investigating SD-101, Dynavax's intratumoral TLR9 agonist, in combination with KEYTRUDA® (pembrolizumab), an anti-PD-1 therapy developed by Merck (known as MSD outside the United States and Canada). The results provide insight into the immune mechanisms underpinning the activity of SD-101 and its effect on the tumor microenvironment.

Dynavax is also presenting preclinical data demonstrating significant anti-tumor activity of an inhaled TLR9 agonist in mice bearing lung tumors. This treatment highlights the synergy of the TLR9 agonist with anti-PD-1 leading to further reduction of both lung tumor burden and metastases in other organs along with long-term survival of treated mice. These studies provide the rationale for the development of DV281, a TLR9 agonist optimized for aerosol delivery. DV281, in combination with anti-PD-1 therapy, will enter clinical studies in non-small cell lung carcinoma patients later this year.

A third presentation shows that intratumoral vaccination with nanoparticles incorporating tumor antigen peptides and a TLR9 agonist provides anti-tumor immunity superior to conventional subcutaneous vaccination. Direct intratumoral vaccination using this novel vaccine platform and mode of administration significantly increases both the magnitude and functional activity of vaccine-primed cytotoxic T lymphocytes (CTL) and enhances control of metastatic disease.

The details of the poster presentations are as follows:

Pharmacodynamic changes confirm the mechanism of action mediating SD-101 efficacy, in combination with pembrolizumab, in a phase 1b/2 study in metastatic melanoma (MEL-01)

Development of an inhaled TLR9 agonist for the immunotherapy of lung cancer

Intratumoral administration of a TLR9-adjuvanted nanoparticle cancer vaccine stimulates more effective immunity in both injected and un-injected tumor sites compared to subcutaneous administration

About SD-101

SD-101 is Dynavax's proprietary, second-generation, TLR9 agonist CpG-C class oligodeoxynucleotide. SD-101 is being studied for its multiple anti-tumor activities in innate immune cells and activation of plasmacytoid dendritic cells to stimulate T cells specific for antigens released from dying tumor cells. TLR9 agonists such as SD-101 enhance T and B cell responses and provide potent Type 1 interferon induction and maturation of plasmacytoid dendritic cells to antigen-presenting cells. SD-101 is being evaluated in several Phase 1/2 oncology studies to assess its safety and activity.

For information about SD-101 trials that are currently recruiting patients, please visit www.clinicaltrials.gov.

About Dynavax

Dynavax is a clinical-stage immunology company focused on leveraging the power of the body's innate and adaptive immune responses through toll-like receptor stimulation. Dynavax is developing product candidates for use in multiple cancer indications, as a vaccine for the prevention of hepatitis B and as a disease modifying therapy for asthma. Dynavax's lead product candidates are SD-101, an investigational cancer immunotherapeutic currently in Phase 1/2 studies, and HEPLISAV-B, a Phase 3 investigational adult hepatitis B vaccine. For more information, visit www.dynavax.com.

Forward-Looking Statements

This press release contains "forward-looking" statements, including expectations for the conduct and timing of clinical trials of SD-101, and other investigational compounds. Actual results may differ materially from those set forth in this press release due to the risks and uncertainties inherent in our business, including whether we can timely provide adequate clinical supplies; initiation, enrollment and completion of clinical trials of SD-101; the results of clinical trials and the impact of those results on the initiation or continuation of subsequent trials and issues arising in the regulatory process; the ability to successfully develop and commercialize SD-101; and whether or not Dynavax and parties with whom we are collaborating may reach any future agreement on further studies or a more extensive collaboration beyond the clinical trials contemplated under the existing agreements, as well as other risks detailed in the "Risk Factors" section of our current periodic reports with the SEC. We undertake no obligation to revise or update information herein to reflect events or circumstances in the future, even if new information becomes available. Information on Dynavax's website at www.dynavax.com is not incorporated by reference in our current periodic reports with the SEC.

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.