What changed, and when

Sanofi moves to buy Dynavax for $2.2B ($15.50 per share) in cash, valuing the deal at about $2.2 billion, with close targeted in Q1 2026, subject to customary conditions including HSR review and a majority tender. (Sanofi press release). Independent coverage confirms per-share terms, equity value, tender structure and timeline. (Reuters, Investor’s Business Daily).

60-second thesis frame

This is a vaccines-focused tuck-in that adds an on-market adult hepatitis B vaccine with a differentiated two-dose, one-month schedule and a shingles candidate showing Shingrix-comparable immunogenicity with lower reactogenicity in early testing, which, if reproduced in larger and older cohorts, could open an attractive, durable adult franchise. HEPLISAV-B’s label and FDA page confirm adult indication and product status, and its 2-dose option fits CDC adult HepB guidance that explicitly allows a 2-dose HEPLISAV-B series for ages 19–59. (FDA HEPLISAV-B page, CDC adult schedule PDF) Early Z-1018 data indicate antibody and CD4+ T-cell responses comparable to GSK’s Shingrix with fewer grade 2/3 reactions, but the program remains Phase 1/2 and must prove durability and performance in ≥70-year adults. (Dynavax topline release, Reuters shingles study note) On access, U.S. Medicare Part D has zero cost-sharing for ACIP-recommended adult vaccines since 2023, a tailwind for uptake. (CMS fact sheet)
Note, some media discuss possible U.S. policy shifts to immunization recommendations, which are not reflected on CDC’s posted adult schedule as of Aug 7, 2025; we privilege the current CDC primary pages for payer and utilization assumptions. (CDC adult schedule, Reuters coverage).

The seven diligence questions

Clinical

• Can Z-1018 reproduce early immunogenicity and tolerability in a powered cohort ≥70 years, and what are the pre-specified non-inferiority or superiority margins versus Shingrix in Part 2 and Phase 3? (ClinicalTrials.gov NCT06569823, FDA SHINGRIX label)
• What is the durability of Z-1018 responses at 12–24 months, and are there signals in frailty subgroups or immunocompromised populations? (Dynavax topline release)

Payer or Access

• With Medicare Part D eliminating cost sharing for ACIP-recommended adult vaccines, how much incremental adherence uplift can HEPLISAV-B and a future Z-1018 capture in seniors and commercial lives? (CMS release)
• Are coding and payment friction points resolved, including product CPT 90739 and admin codes, for retail and provider-office settings? (HEPLISAV-B HCP ordering and coding sheet)

Ops or Adoption

• Can Sanofi scale CpG-adjuvanted supply reliably, and are there any bottlenecks in adjuvant or fill-finish capacity that could cap HEPLISAV-B growth post-integration? (Company ops not detailed in the deal release; monitor CMC in filings, PubMed case study)

Competitive

• How does Z-1018 position versus Shingrix’s updated pre-filled syringe presentation and GSK’s entrenched market access and physician familiarity? (GSK press note on pre-filled syringe, FDA SHINGRIX page)

Team or Cap table

• Is the 39% premium justified given Dynavax’s prior “distress zone” Altman Z-score and reliance on a single commercial asset? (GuruFocus analysis)

Red flags

• Z-1018 is early, and effect-size or safety could attenuate in older adults, risking an expensive Phase 3 with ambiguous differentiation versus Shingrix. (Dynavax topline release, Reuters shingles study note)
• HEPLISAV-B label expansion has faced setbacks, limiting near-term TAM unless payer and practice adoption bridges the gap. (Reuters on FDA declining expanded use, May 2024, FDA HEPLISAV-B page)
• Policy noise around U.S. immunization recommendations creates headline risk, so utilization assumptions should anchor to current CDC schedules until official changes are posted. (CDC adult schedule)

Next catalyst

Tender offer launch and filing of Schedule TO and Dynavax 14D-9, HSR waiting-period milestones, and updated timelines for Z-1018 Part 2 in ≥70-year adults. (Sanofi press release, ClinicalTrials.gov NCT06569823)

FAQ

• What exactly changed by Sanofi’s acquisition of Dynavax news on 24 Dec 2025, and why does it matter for adult vaccines?
  Sanofi agreed to buy Dynavax for $15.50 per share in cash, adding HEPLISAV-B and the Z-1018 shingles candidate, which strengthens Sanofi’s adult immunization footprint. (Sanofi press release, Reuters)
• What is the regulatory path after the Dynavax acquisition by Sanofi and what are the next formal steps in the US, UK, and EU?
  In the U.S., the deal proceeds via a cash tender offer and HSR review, with close aimed for Q1 2026; HEPLISAV-B remains FDA-approved for adults. (Sanofi press release, FDA HEPLISAV-B page)
• Which endpoints in the Z-1018 program were cited in the 24 Aug 2025 early results, and how meaningful was the effect size?
  Dynavax reported comparable antibody and CD4+ T-cell responses to Shingrix, with lower grade 2/3 local and systemic reactions in adults 50–69; durability and ≥70-year performance remain to be shown. (Dynavax topline release, Reuters study note)
• What safety issues matter post–Dynavax acquisition and do they change real-world use for HEPLISAV-B?
  HEPLISAV-B carries standard HepB vaccine cautions, and Z-1018’s early tolerability profile appears favorable; the key risk remains translation to older and immunocompromised populations. (FDA HEPLISAV-B page, Dynavax topline release)
• How will major U.S. payers treat access after the 24 Dec 2025 Dynavax acquisition news, including prior auth and billing, and are codes available?
  Adult vaccines recommended by ACIP are $0 cost sharing under Medicare Part D since 2023, and HEPLISAV-B uses CPT 90739 with standard admin codes, reducing friction at point of care. (CMS release, HEPLISAV-B HCP coding sheet)

Publisher / Disclosure

Publisher: LucidQuest Ventures Ltd. Produced: 24 Dec 2025, 10:30 London. Purpose: general and impersonal information. Not investment research or advice, no offer or solicitation, no suitability assessment. UK: directed at investment professionals under Article 19(5) and certain high-net-worth entities under Article 49(2)(a)–(d) of the Financial Promotion Order 2005. Others should not act on this. Sources and accuracy: public sources believed reliable, provided “as is,” may change without notice. No duty to update. Past performance is not reliable. Forward-looking statements carry risks. Methodology: questions-first framework using public sources. No conflicts. Authors do not hold positions unless stated. © 2025 LucidQuest Ventures Ltd.

Entities / Keywords

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