# EDGAR Filing Document

**Accession Number:** 0001029142
**File Stem:** 0001193125-25-332269
**Filing Date:** 2025-12
**Character Count:** 41389
**Document Hash:** 1778999349d65ef3e861f44a44d2fcf0
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-332269.hdr.sgml**: 20251229

**ACCESSION NUMBER**: 0001193125-25-332269

**CONFORMED SUBMISSION TYPE**: SC14D9C

**PUBLIC DOCUMENT COUNT**: 4

**FILED AS OF DATE**: 20251229

**DATE AS OF CHANGE**: 20251229

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** DYNAVAX TECHNOLOGIES CORP
- **CENTRAL INDEX KEY:** 0001029142
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 330728374
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC14D9C
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-80035
- **FILM NUMBER:** 251603058

**BUSINESS ADDRESS:**
- **STREET 1:** 2100 POWELL STREET
- **STREET 2:** SUITE 720
- **CITY:** EMERYVILLE
- **STATE:** CA
- **ZIP:** 94608
- **BUSINESS PHONE:** 5108485100

**MAIL ADDRESS:**
- **STREET 1:** 2100 POWELL STREET
- **STREET 2:** SUITE 720
- **CITY:** EMERYVILLE
- **STATE:** CA
- **ZIP:** 94608
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** DYNAVAX TECHNOLOGIES CORP
- **CENTRAL INDEX KEY:** 0001029142
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 330728374
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC14D9C

**BUSINESS ADDRESS:**
- **STREET 1:** 2100 POWELL STREET
- **STREET 2:** SUITE 720
- **CITY:** EMERYVILLE
- **STATE:** CA
- **ZIP:** 94608
- **BUSINESS PHONE:** 5108485100

**MAIL ADDRESS:**
- **STREET 1:** 2100 POWELL STREET
- **STREET 2:** SUITE 720
- **CITY:** EMERYVILLE
- **STATE:** CA
- **ZIP:** 94608

**UNITED STATES** 

**SECURITIES AND EXCHANGE COMMISSION** 

**Washington, D.C. 20549** 

**SCHEDULE 14D-9** 

**(Rule 14d-101)** 

**SOLICITATION/RECOMMENDATION STATEMENT** 

**UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934** 

## Dynavax Technologies Corporation
**(Name of Subject Company)** 

**(Name of Person(s) Filing Statement)** 

**COMMON STOCK, PAR VALUE $0.001 PER SHARE** 

**(Title of Class of Securities)** 

**268158201** 

**(CUSIP Number of Class of Securities)** 

**Ryan Spencer** 

**Chief Executive Officer** 

**Dynavax Technologies Corporation** 

**2100 Powell Street, Suite 720** 

**Emeryville, California 94608** 

**(510) 848-5100** 

***With copies to:***

**Barbara L. Borden** 

**Bill Roegge** 

**Steven M. Przesmicki** 

**Cooley LLP** 

**10265 Science Center Drive** 

**San Diego, California 92121** 

**(858) 550-6000** 

**(Name, address, and telephone numbers of person authorized to receive notices and communications** 

**on behalf of the persons filing statement)** 

☒ Check the box if the filing relates solely to preliminary communications made before the commencement of a
tender offer.

------

This Schedule 14D-9 filing relates solely to preliminary communications made before the commencement of a planned tender offer (the "Offer") by Samba Merger Sub, Inc., a Delaware corporation ("Purchaser"), a wholly owned subsidiary of Sanofi, a French société anonyme ("Parent"), to acquire all of the issued and outstanding shares of common stock, par value $0.001 per share, of Dynavax Technologies Corporation, a Delaware corporation (the "Company" or "Dynavax"), to be commenced pursuant to the Agreement and Plan of Merger, dated as of December 23, 2025, by and among Parent, Purchaser and the Company (the "Merger Agreement"). Upon the consummation of the Offer, Purchaser will merge with and into the Company (the "Merger") pursuant to Section 251(h) of the Delaware General Corporation Law, with the Company as the surviving corporation. This Schedule 14D-9 filing consists of the following documents relating to the proposed Offer and Merger:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Exhibit 99.1: Email from Ryan Spencer, Chief Executive Officer of the Company, to employees on December 24,
2025. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Exhibit 99.2: Letter to Dynavax Key Partners, first sent on December 24, 2025.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Exhibit 99.3: Ryan Spencer Employee All Hands Meeting Remarks, first used on December 24, 2025.

**<u>Dynavax Note Regarding Forward-Looking Statements</u>**

Certain statements either contained in or incorporated by reference into this document, other than purely historical information, including statements relating to the sale of Dynavax and any statements relating to Dynavax's business and expected operating results, and the assumptions upon which those statements are based, are "forward-looking statements." These forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as "believes," "plans," "anticipates," "projects," "estimates," "expects," "intends," "strategy," "future," "opportunity," "may," "will," "should," "could," "potential," or similar expressions. Such forward-looking statements include those relating to the ability to complete and the timing of completion of the transactions contemplated by the Merger Agreement including the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions set forth in the Merger Agreement, including the time and benefits thereof, and the possibility of any termination of the Merger Agreement; potential effect of the merger on Dynavax's clinical pipeline, market share and beliefs that hepatitis B and shingles represent significant adult vaccination opportunities and important public health needs, and other statements that are not historical facts. The forward-looking statements contained in this document are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. Actual results and the timing of events may differ materially from those anticipated in such forward-looking statements because of risks associated with uncertainties which include, without limitation, risks related to the timing of the tender offer and the subsequent merger; whether sufficient stockholders of Dynavax will tender their shares in the tender offer; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the offer or the merger may not be satisfied or waived, including that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the tender offer or the merger; risks associated with acquisitions, such as the risk that the effects of disruption from the transactions of Dynavax's business and the fact that the announcement and pendency of the transactions may make it more difficult to establish or maintain relationships with employees and business partners; as well as other risks related to Dynavax's businesses detailed in Dynavax's public filings with the SEC from time to time, including the most recent Annual Reports on Form 10-K for the year ended December 31, 2024, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. The reader is cautioned not to unduly rely on these forward-looking statements. Dynavax expressly disclaims any intent or obligation to update or revise publicly these forward-looking statements except as required by law.

Additional Information for US Shareholders and Where to Find It

The tender offer for the outstanding shares of Dynavax common stock referenced in this communication has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell shares of Dynavax, nor is it a substitute for the tender offer materials that Sanofi and its acquisition subsidiary will file with the U.S. Securities and Exchange Commission (the "***SEC***") upon

------

commencement of the tender offer. At the time the tender offer is commenced, Sanofi and its acquisition subsidiary will file tender offer materials on Schedule TO, and Dynavax will file a Solicitation/Recommendation Statement on Schedule 14D-9 with the SEC with respect to the tender offer. The tender offer materials (including an Offer to Purchase, a related Letter of Transmittal and certain other tender offer documents) and the Solicitation/Recommendation Statement will contain important information. HOLDERS OF SHARES OF DYNAVAX ARE URGED TO READ THESE DOCUMENTS WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT DYNAVAX STOCKHOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES. The Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, will be made available to all holders of shares of Dynavax at no expense to them. The tender offer materials and the Solicitation/Recommendation Statement will be made available for free at the SEC's web site at www.sec.gov. Additional copies may be obtained for free on Dynavax's website at https://investors.dynavax.com/sec-filings.

In addition to the Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, Sanofi files annual and special reports and other information with the SEC and Dynavax files annual, quarterly and special reports and other information with the SEC. You may read and copy any reports or other information filed by Sanofi and Dynavax at the SEC public reference room at 100 F. Street, N.E., Washington D.C. 20549. Please call the Commission at 1-800-SEC-0330 for further information on the public reference room. Sanofi's and Dynavax's filings with the SEC are also available to the public from commercial document-retrieval services and at the website maintained by the SEC at <u>www.sec.gov</u>.

## Exhibit 99.1

**Exhibit 99.1** 

**Subject:** An Important Update About Our Company's Future

Dear Team,

Earlier today, we announced that Dynavax has entered into an agreement to be acquired by Sanofi, a global pharmaceutical company with world-class leadership in launching and commercializing innovative vaccines, and deep scientific, operational, and commercial capabilities.

This was not a decision we made lightly. After a thorough evaluation by our Board of Directors, we believe this strategic move represents the best path forward for our vaccine programs and our science, as well as our patients, employees, and our shareholders.

**Why we made this decision** 

Over the past three decades, you have built a truly special company, creating an incredible legacy. As HEPLISAV-B continues to grow its market leadership position and as our pipeline advances, the scale, capital, and global infrastructure required to bring these vaccines to patients continue to grow. Becoming a part of Sanofi will accelerate that journey and significantly increase the likelihood that our work reaches many more patients around the world, faster.

**What this means right now** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• For today and until the acquisition officially closes, it will be business as usual in how we operate. Your role,
manager, compensation, and benefits remain the same.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• We will continue to focus on executing our day-to-day work in advancing our science and programs.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• The acquisition is expected to close in the first quarter of 2026, subject to customary regulatory reviews.

**What we don't know yet** 

Some of you may be involved in integration planning activities, and any decisions regarding future organizational structure or roles will be communicated transparently, as new information becomes available, and with respect for everyone involved.

**Our commitment to you** 

We know this news can bring uncertainty and a wide range of emotions. Our leadership team is committed to:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Communicating clearly and regularly

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Sharing information as soon as it becomes available

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Treating every employee with fairness and respect throughout this process

**Next steps** 

We will host an optional All Hands Meeting to walk through the announcement, the timeline, and to answer your questions. We understand that the timing may be difficult due to the holidays, and so we also plan to hold another All Hands Meeting in early January to reconnect after the holiday break and to address any additional questions you may have. Further, our Dusseldorf site will also receive an invitation for a separate All Hands Meeting as another opportunity to connect with leadership in the coming days.

Thank you for your dedication, resilience, and belief in our mission. I am incredibly proud of what we have built here, and our impact on improving public health truly matters. This agreement is a testament to the strength of your work and will ensure that Dynavax's legacy endures through our joint mission to bring life-saving vaccines to many more people around the world.

Sincerely,

Ryan

\*\*\*\*

------

**Betreff: Eine wichtige Mitteilung über die Zukunft unseres Unternehmens** 

Liebe Kolleginnen und Kollegen,

Heute haben wir bekanntgegeben, dass Dynavax eine Vereinbarung zur Übernahme durch Sanofi getroffen hat – ein globales Pharmaunternehmen mit erstklassiger Expertise in der Einführung und Vermarktung innovativer Impfstoffe sowie umfassenden wissenschaftlichen, operativen und kommerziellen Fähigkeiten.

Diese Entscheidung haben wir nicht leichtfertig getroffen. Nach einer gründlichen Prüfung durch unseren Aufsichtsrat sind wir überzeugt, dass dieser strategische Schritt den besten Weg für unsere Impfstoffprogramme, unsere Wissenschaft sowie für unsere Patientinnen und Patienten, Mitarbeitenden und Aktionäre darstellt.

Warum wir diese Entscheidung getroffen haben

In den vergangenen drei Jahrzehnten habt ihr ein wirklich außergewöhnliches Unternehmen aufgebaut und ein beeindruckendes Vermächtnis geschaffen. Während HEPLISAV-B seine führende Marktposition weiter ausbaut und unsere Pipeline voranschreitet, steigen die Anforderungen an Größe, Kapital und globale Infrastruktur, um diese Impfstoffe zu den Patientinnen und Patienten zu bringen. Die Integration in Sanofi wird diesen Weg beschleunigen und die Wahrscheinlichkeit deutlich erhöhen, dass unsere Arbeit weltweit schneller mehr Menschen erreicht.

Was das jetzt bedeutet

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Bis zum offiziellen Abschluss der Übernahme bleibt alles wie gewohnt: Eure Rolle, Eure Führungskraft,
Eure Vergütung und Sozialleistungen bleiben unverändert.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Wir konzentrieren uns weiterhin darauf, unsere tägliche Arbeit zur Weiterentwicklung unserer Wissenschaft
und Programme auszuführen.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Der Abschluss der Übernahme wird im ersten Quartal 2026 erwartet, vorbehaltlich der üblichen
behördlichen Prüfungen.

Was wir noch nicht wissen

Einige von Euch werden möglicherweise in Integrationsplanungen eingebunden. Entscheidungen zur zukünftigen Organisationsstruktur oder zu Rollen werden transparent kommuniziert, sobald neue Informationen vorliegen – stets mit Respekt gegenüber allen Beteiligten.

Unser Versprechen an Euch

Wir wissen, dass diese Nachricht Unsicherheit und unterschiedliche Emotionen auslösen kann. Unser Führungsteam verpflichtet sich:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Klar und regelmäßig zu kommunizieren

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Informationen so schnell wie möglich weiterzugeben

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Jede Mitarbeiterin und jeden Mitarbeiter fair und respektvoll zu behandeln

Nächste Schritte

Wir werden ein optionales All-Hands-Meeting veranstalten, um die Ankündigung, den Zeitplan und eure Fragen zu besprechen. Uns ist bewusst, dass der Zeitpunkt aufgrund der Feiertage schwierig sein kann. Daher planen wir ein weiteres All-Hands-Meeting Anfang Januar, um nach der Feiertagspause erneut in den Austausch zu gehen und zusätzliche Fragen zu klären. Darüber hinaus wird unser Standort in Düsseldorf eine Einladung zu einem separaten All-Hands-Meeting erhalten, um in den kommenden Tagen eine weitere Gelegenheit zum Austausch mit der Geschäftsführung zu bieten.

Vielen Dank für Euer Engagement, Euer Durchhaltevermögen und Euren Glauben an unsere Mission. Ich bin unglaublich stolz auf das, was wir hier aufgebaut haben – unser Beitrag zur Verbesserung der öffentlichen Gesundheit ist von großer Bedeutung. Diese Vereinbarung ist ein Beweis für die Stärke Eurer Arbeit und stellt sicher, dass das Erbe von Dynavax fortbesteht durch unsere gemeinsame Mission, lebensrettende Impfstoffe zu noch mehr Menschen weltweit zu bringen.

Mit freundlichen Grüßen

Ryan

------

**<u>About Dynavax</u>**

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<sup>®</sup> 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<sup>®</sup> adjuvant. For more information about Dynavax's marketed products and development pipeline, visit <u>www.dynavax.com</u>.

**<u>Dynavax Note Regarding Forward-Looking Statements</u>**

Certain statements either contained in or incorporated by reference into this press release, other than purely historical information, including statements relating to the sale of Dynavax and any statements relating to Dynavax's business and expected operating results, and the assumptions upon which those statements are based, are "forward-looking statements." These forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as "believes," "plans," "anticipates," "projects," "estimates," "expects," "intends," "strategy," "future," "opportunity," "may," "will," "should," "could," "potential," or similar expressions. Such forward-looking statements include those relating to the ability to complete and the timing of completion of the transactions contemplated by the Agreement and Plan of Merger dated as of December 23, 2025 by and among Dynavax, Samba Merger Sub, Inc., and Sanofi (the "***Merger Agreement***") including the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions set forth in the Merger Agreement, including the time and benefits thereof, and the possibility of any termination of the Merger Agreement; potential effect of the merger on Dynavax's clinical pipeline, market share and beliefs that hepatitis B and shingles represent significant adult vaccination opportunities and important public health needs, and other statements that are not historical facts. The forward-looking statements contained in this document are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. Actual results and the timing of events may differ materially from those anticipated in such forward-looking statements because of risks associated with uncertainties which include, without limitation, risks related to the timing of the tender offer and the subsequent merger; whether sufficient stockholders of Dynavax will tender their shares in the tender offer; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the offer or the merger may not be satisfied or waived, including that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the tender offer or the merger; risks associated with acquisitions, such as the risk that the effects of disruption from the transactions of Dynavax's business and the fact that the announcement and pendency of the transactions may make it more difficult to establish or maintain relationships with employees and business partners; as well as other risks related to Dynavax's businesses detailed in Dynavax's public filings with the SEC from time to time, including the most recent Annual Reports on Form 10-K for the year ended December 31, 2024, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. The reader is cautioned not to unduly rely on these forward-looking statements. Dynavax expressly disclaims any intent or obligation to update or revise publicly these forward-looking statements except as required by law.

Additional Information for US Shareholders and Where to Find It

The tender offer for the outstanding shares of Dynavax common stock referenced in this communication has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell shares of Dynavax, nor is it a substitute for the tender offer materials that Sanofi and its acquisition subsidiary will file with the U.S. Securities and Exchange Commission (the "***SEC***") upon commencement of the tender offer. At the time the tender offer is commenced, Sanofi and its acquisition subsidiary will file tender offer materials on Schedule TO, and Dynavax will file a Solicitation/Recommendation Statement on Schedule 14D-9 with the SEC with respect to the tender offer. The tender offer materials (including an Offer to Purchase, a related Letter of Transmittal and certain other tender offer documents) and the Solicitation/Recommendation Statement will contain important information. HOLDERS OF SHARES OF DYNAVAX ARE URGED TO READ THESE DOCUMENTS WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT DYNAVAX STOCKHOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES. The Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, will be made available to all holders of shares of Dynavax at no expense to them. The tender offer materials and the Solicitation/Recommendation Statement will be made available for free at the SEC's web site at www.sec.gov. Additional copies may be obtained for free on Dynavax's website at https://investors.dynavax.com/sec-filings.

------

In addition to the Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, Sanofi files annual and special reports and other information with the SEC and Dynavax files annual, quarterly and special reports and other information with the SEC. You may read and copy any reports or other information filed by Sanofi and Dynavax at the SEC public reference room at 100 F. Street, N.E., Washington D.C. 20549. Please call the Commission at 1-800-SEC-0330 for further information on the public reference room. Sanofi's and Dynavax's filings with the SEC are also available to the public from commercial document-retrieval services and at the website maintained by the SEC at <u>www.sec.gov</u>.

## Exhibit 99.2

**Exhibit 99.2** 

**Dynavax Key Partners, Vendors, and Customers Letter** 

**To:** Partners / Vendors / Customers

**From:** 

**Subject:** Sanofi to Acquire Dynavax

Today, we announced that we have entered into an agreement to be acquired by Sanofi. A press release announcing the news is available here: https://investors.dynavax.com/news-releases/news-release-details/sanofi-acquire-dynavax-adding-marketed-adult-hepatitis-b-vaccine.

This acquisition aligns with Sanofi's strategic ambition to shape the future of immunization. Dynavax further strengthens Sanofi's adult vaccination portfolio with a commercial hepatitis B adult vaccine and promising shingles vaccine candidate, addressing significant unmet public health needs. We believe Sanofi's commercial reach, development capabilities, and commitment to evidence-based immunization will amplify the opportunity for HEPLISAV-B and our innovative pipeline to address important public health needs, further advancing our mission to help protect the world against infectious disease.

For the time being, the transaction is expected to have no impact on our relationship with you, including any previously disclosed timelines.

Until the transaction closes, which we expect in the first quarter of 2026, we will continue to operate as a separate, standalone business, and our operations will continue unaffected by the proposed acquisition by Sanofi. As we progress toward closing the transaction, we are committed to providing updates when we have additional information to share. In the meantime, if you have any questions about this news and would like to discuss further, please do not hesitate to reach out to your normal Dynavax point of contact directly.

We are incredibly grateful to you for being a part of Dynavax's journey.

Sincerely,

**<u>About Dynavax</u>**

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<sup>®</sup> 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<sup>®</sup> adjuvant. For more information about Dynavax's marketed products and development pipeline, visit <u>www.dynavax.com</u>.

------

**<u>Dynavax Note Regarding Forward-Looking Statements</u>**

Certain statements either contained in or incorporated by reference into this press release, other than purely historical information, including statements relating to the sale of Dynavax and any statements relating to Dynavax's business and expected operating results, and the assumptions upon which those statements are based, are "forward-looking statements." These forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as "believes," "plans," "anticipates," "projects," "estimates," "expects," "intends," "strategy," "future," "opportunity," "may," "will," "should," "could," "potential," or similar expressions. Such forward-looking statements include those relating to the ability to complete and the timing of completion of the transactions contemplated by the Agreement and Plan of Merger dated as of December 23, 2025 by and among Dynavax, Samba Merger Sub, Inc., and Sanofi (the "***Merger Agreement***") including the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions set forth in the Merger Agreement, including the time and benefits thereof, and the possibility of any termination of the Merger Agreement; potential effect of the merger on Dynavax's clinical pipeline, market share and beliefs that hepatitis B and shingles represent significant adult vaccination opportunities and important public health needs, and other statements that are not historical facts. The forward-looking statements contained in this document are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. Actual results and the timing of events may differ materially from those anticipated in such forward-looking statements because of risks associated with uncertainties which include, without limitation, risks related to the timing of the tender offer and the subsequent merger; whether sufficient stockholders of Dynavax will tender their shares in the tender offer; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the offer or the merger may not be satisfied or waived, including that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the tender offer or the merger; risks associated with acquisitions, such as the risk that the effects of disruption from the transactions of Dynavax's business and the fact that the announcement and pendency of the transactions may make it more difficult to establish or maintain relationships with employees and business partners; as well as other risks related to Dynavax's businesses detailed in Dynavax's public filings with the SEC from time to time, including the most recent Annual Reports on Form 10-K for the year ended December 31, 2024, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. The reader is cautioned not to unduly rely on these forward-looking statements. Dynavax expressly disclaims any intent or obligation to update or revise publicly these forward-looking statements except as required by law.

------

Additional Information for US Shareholders and Where to Find It

The tender offer for the outstanding shares of Dynavax common stock referenced in this communication has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell shares of Dynavax, nor is it a substitute for the tender offer materials that Sanofi and its acquisition subsidiary will file with the U.S. Securities and Exchange Commission (the "***SEC***") upon commencement of the tender offer. At the time the tender offer is commenced, Sanofi and its acquisition subsidiary will file tender offer materials on Schedule TO, and Dynavax will file a Solicitation/Recommendation Statement on Schedule 14D-9 with the SEC with respect to the tender offer. The tender offer materials (including an Offer to Purchase, a related Letter of Transmittal and certain other tender offer documents) and the Solicitation/Recommendation Statement will contain important information. HOLDERS OF SHARES OF DYNAVAX ARE URGED TO READ THESE DOCUMENTS WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT DYNAVAX STOCKHOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES. The Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, will be made available to all holders of shares of Dynavax at no expense to them. The tender offer materials and the Solicitation/Recommendation Statement will be made available for free at the SEC's web site at www.sec.gov. Additional copies may be obtained for free on Dynavax's website at https://investors.dynavax.com/sec-filings.

In addition to the Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, Sanofi files annual and special reports and other information with the SEC and Dynavax files annual, quarterly and special reports and other information with the SEC. You may read and copy any reports or other information filed by Sanofi and Dynavax at the SEC public reference room at 100 F. Street, N.E., Washington D.C. 20549. Please call the Commission at 1-800-SEC-0330 for further information on the public reference room. Sanofi's and Dynavax's filings with the SEC are also available to the public from commercial document-retrieval services and at the website maintained by the SEC at <u>www.sec.gov</u>.

## Exhibit 99.3

**Exhibit 99.3** 

**All Hands Meeting – CEO Remarks** 

Good morning, everyone.

Thank you for joining today's All Hands meeting, especially on short notice. I know many of you have already seen the news: earlier today, we announced that Dynavax has entered into an agreement to be acquired by Sanofi, a global leader in vaccines.

I want to start by acknowledging that this is a significant moment for our company—and for each of you. Change of this magnitude brings questions, uncertainty, and a range of emotions. I want you to know that our leadership team is committed to communicating openly, sharing information as soon as it's available, and treating every employee with fairness and respect throughout this process.

This decision was not made lightly. After a thorough evaluation by our Board of Directors, we believe that being acquired by Sanofi is the best path forward for our vaccine programs, our science, our patients, our shareholders, and employees. As our programs advance, the scale, capital, and global infrastructure required to bring our vaccines to patients have grown. Becoming a part of Sanofi will accelerate our mission and maximize our impact, and help bring our innovative vaccines to many more people around the world, faster.

For today and the period leading up to the anticipated acquisition close in Q1, it is business as usual.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Nothing changes in how we operate.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• Your role, your manager, your compensation, and your benefits all remain exactly the
same.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• We are still Dynavax, operating as Dynavax. Our absolute focus must remain on executing our day-to-day work, advancing our science, and serving our patients with the excellence you always demonstrate.

Your hard work has built a legacy that will not only endure but will be significantly amplified through this partnership, bringing life-saving vaccines to many more people around the world.

Today, we are happy to address any questions you have. We also plan to hold another All Hands Meeting in early January to reconnect after the holiday break and to address any additional questions.

Thank you for your dedication, resilience, and belief in our mission. What we have built here is truly special, and this acquisition is a testament to your work and impact on public health. Together, we will ensure Dynavax's legacy endures and our science reaches even more patients worldwide.

**<u>About Dynavax</u>**

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<sup>®</sup> 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<sup>®</sup> adjuvant. For more information about Dynavax's marketed products and development pipeline, visit <u>www.dynavax.com</u>.

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**<u>Dynavax Note Regarding Forward-Looking Statements</u>**

Certain statements either contained in or incorporated by reference into this press release, other than purely historical information, including statements relating to the sale of Dynavax and any statements relating to Dynavax's business and expected operating results, and the assumptions upon which those statements are based, are "forward-looking statements." These forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as "believes," "plans," "anticipates," "projects," "estimates," "expects," "intends," "strategy," "future," "opportunity," "may," "will," "should," "could," "potential," or similar expressions. Such forward-looking statements include those relating to the ability to complete and the timing of completion of the transactions contemplated by the Agreement and Plan of Merger dated as of December 23, 2025 by and among Dynavax, Samba Merger Sub, Inc., and Sanofi (the "***Merger Agreement***") including the parties' ability to satisfy the conditions to the consummation of the tender offer and the other conditions set forth in the Merger Agreement, including the time and benefits thereof, and the possibility of any termination of the Merger Agreement; potential effect of the merger on Dynavax's clinical pipeline, market share and beliefs that hepatitis B and shingles represent significant adult vaccination opportunities and important public health needs, and other statements that are not historical facts. The forward-looking statements contained in this document are based on current expectations and assumptions that are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. Actual results and the timing of events may differ materially from those anticipated in such forward-looking statements because of risks associated with uncertainties which include, without limitation, risks related to the timing of the tender offer and the subsequent merger; whether sufficient stockholders of Dynavax will tender their shares in the tender offer; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the offer or the merger may not be satisfied or waived, including that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the tender offer or the merger; risks associated with acquisitions, such as the risk that the effects of disruption from the transactions of Dynavax's business and the fact that the announcement and pendency of the transactions may make it more difficult to establish or maintain relationships with employees and business partners; as well as other risks related to Dynavax's businesses detailed in Dynavax's public filings with the SEC from time to time, including the most recent Annual Reports on Form 10-K for the year ended December 31, 2024, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. The reader is cautioned not to unduly rely on these forward-looking statements. Dynavax expressly disclaims any intent or obligation to update or revise publicly these forward-looking statements except as required by law.

Additional Information for US Shareholders and Where to Find It

The tender offer for the outstanding shares of Dynavax common stock referenced in this communication has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell shares of Dynavax, nor is it a substitute for the tender offer materials that Sanofi and its acquisition subsidiary will file with the U.S. Securities and Exchange Commission (the "***SEC***") upon commencement of the tender offer. At the time the tender offer is commenced, Sanofi and its acquisition subsidiary will file tender offer materials on Schedule TO, and Dynavax will file a Solicitation/Recommendation Statement on Schedule 14D-9 with the SEC with respect to the tender offer. The tender offer materials (including an Offer to Purchase, a related Letter of Transmittal and certain other tender offer documents) and the Solicitation/Recommendation Statement will contain important information.

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HOLDERS OF SHARES OF DYNAVAX ARE URGED TO READ THESE DOCUMENTS WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT DYNAVAX STOCKHOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES. The Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, will be made available to all holders of shares of Dynavax at no expense to them. The tender offer materials and the Solicitation/Recommendation Statement will be made available for free at the SEC's web site at www.sec.gov. Additional copies may be obtained for free on Dynavax's website at https://investors.dynavax.com/sec-filings.

In addition to the Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, Sanofi files annual and special reports and other information with the SEC and Dynavax files annual, quarterly and special reports and other information with the SEC. You may read and copy any reports or other information filed by Sanofi and Dynavax at the SEC public reference room at 100 F. Street, N.E., Washington D.C. 20549. Please call the Commission at 1-800-SEC-0330 for further information on the public reference room. Sanofi's and Dynavax's filings with the SEC are also available to the public from commercial document-retrieval services and at the website maintained by the SEC at <u>www.sec.gov</u>.