Dynavax Presents Positive Topline Data from Part 1 of Phase 1/2 Trial for Shingles Vaccine Candidate at IDWeek 2025 and Announces Initiation of Part 2 of Trial

• Z-1018 demonstrates comparable antibody and CD4+ T-cell responses to Shingrix® with a favorable tolerability profile
• Newly presented data outline robust polyfunctional CD4+ T-cell responses in Z-1018 arms
• Company initiates Part 2 of Phase 1/2 head-to-head versus Shingrix in adults 70 years and older

EMERYVILLE, Calif., Oct. 21, 2025 /PRNewswire/ -- Dynavax Technologies Corporation (Nasdaq: DVAX), a commercial-stage biopharmaceutical company developing and commercializing innovative vaccines, today presented positive topline data from Part 1 of its randomized, observer-blinded, active-controlled Phase 1/2 clinical trial of Z-1018, the Company's novel shingles vaccine candidate, in a late-breaker session at IDWeek 2025. Dynavax also today announced it has initiated Part 2 of the trial evaluating Z-1018 head-to-head versus Shingrix^® in older adults.

"Today's presentation reinforces our belief that Z-1018 has the potential to deliver best-in-class performance by combining robust immunogenicity with a differentiated tolerability profile," said Robert Janssen, M.D., Chief Medical Officer of Dynavax. "With Part 2 now initiated in adults aged 70 and older, we are moving quickly to confirm these advantages by studying our optimal dose of Z-1018 head-to-head versus Shingrix in the population at highest risk for shingles."

Part 1 of the Phase 1/2 trial was a randomized, observer-blinded, active-controlled, dose escalation, multicenter trial to evaluate the safety, tolerability, and immunogenicity of Z-1018 compared to Shingrix in healthy adult participants aged 50 through 69 years. A key objective of Part 1 was to evaluate three different dose levels of gE antigen (50 mcg, 100 mcg, 200 mcg) with two different adjuvant formulations (one with CpG 1018® adjuvant alone and one with CpG 1018 plus alum), as well as 8-week and 12-week dosing regimens. The key safety endpoint was solicited local and systemic post-injection reactions (PIRs), measured for up to seven days following each dose. The key immunogenicity endpoints included vaccine response rates (VRR) for anti-gE IgG antibodies and gE-specific CD4+ T cells, assessed four weeks after the second study injection. VRRs were defined as participants with greater than or equal to 4-fold increase in anti-gE IgG concentration and, separately, greater than or equal to 2-fold increase in CD4+ T-cell frequency over baseline.

Key highlights of the data presentation included:

• Z-1018 adjuvanted with CpG 1018 (with or without alum) showed favorable tolerability and strong humoral and cellular responses across a range of Dynavax-produced gE dosage levels and dosing intervals
• Z-1018 groups elicited high anti-gE IgG concentrations, robust CD4+ T-cell frequencies, and VRRs (per IgG and CD4+ criteria) comparable to Shingrix, at 4 weeks after dose 2
• In new data presented at IDWeek, Z-1018 induced a high proportion of polyfunctional CD4+ T-cell responses exhibiting multiple gE-specific activation markers, supporting the quality and breadth of the cellular immune response
• Formulation consisting of 100 mcg gE adjuvanted with CpG 1018 plus alum, administered at 0 and 8 weeks, was selected for advancement to Part 2 of the Phase 1/2 trial in which adults aged 70 years and older are being enrolled

Part 2 Study Initiated
Dynavax also announced today that the first participants have been dosed in Part 2 of the Phase 1/2 clinical trial. Part 2 of the Phase 1/2 trial is a randomized, active-controlled, multicenter study expected to enroll approximately 324 healthy adults aged 70 years and older at trial sites in Australia and New Zealand. The study is designed to further characterize immunogenicity, safety, and tolerability at the selected Z-1018 dose and regimen, including demonstrating non-inferiority to Shingrix on select immunogenicity measures.
Dynavax anticipates reporting topline Part 2 immunogenicity and safety data in the second half of 2026.

About Shingles
Herpes zoster, or shingles, is caused by reactivation of the varicella-zoster virus and affects approximately 1 in 3 people in their lifetime. The disease is characterized by a painful rash and can lead to serious complications, particularly in older adults. Despite the availability of an effective vaccine, there remains a need for broader access and improved tolerability.

About Z-1018
Z-1018 is an investigational non-live, recombinant subunit vaccine in development for the prevention of shingles in adults aged 50 and over. It combines an antigen, glycoprotein E, with Dynavax's proprietary adjuvant system, CpG 1018, and alum and may help overcome the natural age-related decline in responses to immunization that contributes to the challenge of protecting adults aged 50 and over from shingles.

About Dynavax
Dynavax is a commercial-stage biopharmaceutical company developing and commercializing innovative vaccines to help protect the world against infectious diseases. Dynavax has two commercial products, HEPLISAV-B^® vaccine [Hepatitis B Vaccine (Recombinant), Adjuvanted], which is approved in the U.S., the European Union and the United Kingdom for the prevention of infection caused by all known subtypes of hepatitis B virus in adults 18 years of age and older, and CpG 1018^® adjuvant, currently used in HEPLISAV-B and multiple adjuvanted COVID-19 vaccines. For more information about Dynavax's marketed products and development pipeline, visit www.dynavax.com.

Forward-Looking Statements
This press release contains "forward-looking" statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to a number of risks and uncertainties. All statements that are not historical facts are forward-looking statements. Forward-looking statements can generally be identified by the use of words such as "anticipate," "believe," "continue," "could," "estimate," "expect," "forecast," "intend," "will," "may," "plan," "potential,"  "would" and similar expressions, or the negatives thereof, or they may use future dates. Forward-looking statements made in this document include statements regarding the expected initiation of Part 2 of the Phase 1/2 trial and anticipated benefits from Part 2, the potential for Z-1018 to have a best-in-class profile and possibly disrupt the shingles vaccine market, and the possibility that a vaccine that provides a strong immune response alongside favorable tolerability, compared to the current standard of care, could provide an important new option for protection against shingles. Actual results may differ materially from those set forth in this press release due to the risks and uncertainties inherent in Dynavax's business, including, the risk risks related to the timing of initiation, completion and results of planned clinical studies, risks related to the development and pre-clinical and clinical testing of vaccines containing CpG 1018 adjuvant, as well as other risks detailed in the "Risk Factors" section of its Quarterly Report on Form 10-Q for the three months ended June 30, 2025 and periodic filings made thereafter, as well as discussions of potential risks, uncertainties and other important factors in its other filings with the U.S. Securities and Exchange Commission. These forward-looking statements are made as of the date hereof, are qualified in their entirety by this cautionary statement and Dynavax undertakes 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 its current periodic reports with the SEC.

For Investors/Media:
Paul Cox
pcox@dynavax.com
510-665-0499

Nicole Arndt
narndt@dynavax.com
510-665-7264

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SOURCE Dynavax Technologies