Dynavax Presents Promising Clinical Data from Lead Immuno-Oncology Candidate, SD-101, at the International Congress on Targeted Anticancer Therapies

BERKELEY, CA--(Marketwired - March 06, 2017) - Dynavax Technologies Corporation (NASDAQ: DVAX) announced the presentation of findings in patients with metastatic melanoma in the dose escalation phase of 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. Results evaluating 17 patients for efficacy and 22 patients for safety were reported. In patients naïve to anti-PD-1 treatment, responses were observed in six out of seven patients, for an Overall Response Rate (ORR) of 86%. This includes two (29%) complete responses (CR) and four (57%) partial responses (PR). Target tumor shrinkage was observed in all 7 evaluable patients. In 10 patients with progressive disease who initiated KEYTRUDA anti-PD-1 monotherapy prior to enrollment, one PR was observed and five patients had stable disease (SD) while receiving KEYTRUDA and SD-101, with four of the 10 patients experiencing target tumor shrinkage. These data are being presented by Robert Janssen, M.D., chief medical officer for Dynavax, in an oral presentation at the International Congress on Targeted Anticancer Therapies which begins today in Paris, France.

"We are pleased with the response in the anti-PD-1 naïve group with 2 complete responses and tumor shrinkage in all 7 evaluable patients," said Dr. Janssen. "In addition, we are encouraged to have seen a partial response at the highest dose in the anti-PD-1 refractory group with little toxicity. This allows us to explore higher doses of SD-101 in anti-PD-1 refractory patients in the expansion phase to further develop the best path forward for this hard to treat population."

SD-101 in combination with KEYTRUDA generally was well-tolerated. No dose-limiting toxicities of the combination were observed in any dose cohort, and a maximum tolerated dose (MTD) was not identified. The most common treatment-emergent adverse events were injection site reactions and transient grade 1 to 2 flu-like symptoms, including fever, chills and myalgia that respond to over the counter medications such as acetaminophen. The study also includes biomarker assessments, suggesting that treatment with SD-101 and KEYTRUDA resulted in elevation of gene signatures consistent with an increase in Th1 immune cell types as well as an increase in immune cell infiltrates such as CD8+ T-cells in the tumor microenvironment.