# Vicebio
Vicebio Ltd was a London-headquartered biopharmaceutical startup developing next-generation respiratory vaccines, created by the venture firm Medicxi and acquired by Sanofi in a deal announced on 22 July 2025 and completed on 4 December 2025.[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) • [2](https://www.sanofi.com/en/media-room/press-releases/2025/2025-12-04-10-00-00-3199555) Its pipeline centered on VXB-241, a bivalent vaccine against respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) in exploratory Phase 1 testing, and VXB-251, a preclinical trivalent candidate adding parainfluenza virus type 3 (PIV3).[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150)
| Key facts | |
|---|---|
| Headquarters | London, UK, with locations in Belgium and Australia[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) • [3](https://endpoints.news/sanofi-to-buy-early-stage-vaccine-maker-vicebio-for-1-15b-upfront/) |
| Origin | Created by Medicxi; Molecular Clamp technology licensed from UniQuest, the University of Queensland's commercialization arm[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) |
| CEO | Emmanuel Hanon, former head of GSK vaccine R&D[4](https://endpoints.news/uk-vaccine-startup-vicebio-snags-100m-to-take-on-gsk-pfizer-and-moderna/) |
| Lead asset | VXB-241, bivalent RSV/hMPV vaccine, exploratory Phase 1 in adults 60 and above[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) |
| Last funding | $100 million Series B, 23 September 2024, led by TCGX[5](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html) |
| Outcome | Acquired by Sanofi for $1.15 billion upfront plus up to $450 million in milestones; completed 4 December 2025[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) • [2](https://www.sanofi.com/en/media-room/press-releases/2025/2025-12-04-10-00-00-3199555) |
## What Vicebio did: the Molecular Clamp platform and pipeline
Vicebio described itself as a biopharmaceutical company developing vaccines against life-threatening respiratory viral infections.[5](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html) Its core asset was the Molecular Clamp technology, which stabilizes viral proteins in their native shape so they can be produced at high yield as liquid multivalent formulations.[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) • [6](https://am.gs.com/en-au/advisors/news/press-release/2025/vicebio) Sanofi highlighted the practical consequence: fully liquid combination vaccines storable at 2–8°C in prefilled syringes, without freezing or freeze-drying.[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) According to the company's own announcement, the platform also applies to parainfluenza viruses, influenza, and coronaviruses.[7](https://www.prnewswire.com/news-releases/vicebio-next-generation-vaccine-biotech-to-be-acquired-by-sanofi-for-us1-6-billion-302510454.html)
The clinical pipeline had two named candidates. VXB-241 targeted RSV and hMPV together; at the time of its Phase 1 initiation the company noted there was no commercially available vaccine targeting both viruses.[5](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html) VXB-251, a trivalent candidate adding PIV3, was preclinical at acquisition.[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150)
## Founding, people and origins
Vicebio was created by Medicxi, the European life-sciences venture firm, with investment from Medicxi and a license to the Molecular Clamp technology from UniQuest, the [University of Queensland](https://www.edgepedia.org/university-of-queensland)'s commercialization arm.[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) The technology was developed at UQ by Prof. [Paul Young](https://www.edgepedia.org/paul-young), Prof. Daniel Watterson, and Prof. Keith Chappell.[7](https://www.prnewswire.com/news-releases/vicebio-next-generation-vaccine-biotech-to-be-acquired-by-sanofi-for-us1-6-billion-302510454.html) Endpoints News described the clamp as a second-generation iteration of UQ vaccine technology that was tested but ultimately sidelined in the early days of the Covid-19 pandemic.[4](https://endpoints.news/uk-vaccine-startup-vicebio-snags-100m-to-take-on-gsk-pfizer-and-moderna/)
The company was led by CEO Emmanuel Hanon, who had run GSK's vaccine R&D and moved its RSV vaccine into Phase 3 before departing in 2021, before that shot was approved as Arexvy.[4](https://endpoints.news/uk-vaccine-startup-vicebio-snags-100m-to-take-on-gsk-pfizer-and-moderna/) Vicebio operated from locations in the UK, Belgium, and Australia.[3](https://endpoints.news/sanofi-to-buy-early-stage-vaccine-maker-vicebio-for-1-15b-upfront/)
## Funding history
On 23 September 2024 Vicebio announced a $100 million Series B financing led by TCGX, with investment from Goldman Sachs Alternatives, Avoro Ventures, and venBio, and participation from UniQuest and founding investor Medicxi.[5](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html) The proceeds funded the Phase 1 study of VXB-241 and development of the trivalent VXB-251.[5](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html) Hanon said in September 2024 that he wanted Phase 1 data before potentially moving onto the public markets, an IPO path the acquisition superseded.[4](https://endpoints.news/uk-vaccine-startup-vicebio-snags-100m-to-take-on-gsk-pfizer-and-moderna/)
## Clinical traction before the deal
Vicebio initiated the Phase 1 study of VXB-241 in September 2024, with initial clinical readouts expected mid-2025.[5](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html) • [9](https://www.biocentury.com/article/656546/first-clinical-evidence-spurs-sanofi-s-takeout-of-vicebio-for-1-15b-up-front) By the time of the acquisition announcement in July 2025, an interim analysis of the exploratory Phase 1 study showed a favorable safety and tolerability profile in adults aged 60 and above.[7](https://www.prnewswire.com/news-releases/vicebio-next-generation-vaccine-biotech-to-be-acquired-by-sanofi-for-us1-6-billion-302510454.html) The company also planned to enter Phase 1 with the trivalent vaccine in the coming months, and Hanon said all data seen so far were very encouraging.[3](https://endpoints.news/sanofi-to-buy-early-stage-vaccine-maker-vicebio-for-1-15b-upfront/) BioCentury reported that this first clinical evidence, together with the technology's stability and manufacturing benefits, spurred Sanofi's takeout.[9](https://www.biocentury.com/article/656546/first-clinical-evidence-spurs-sanofi-s-takeout-of-vicebio-for-1-15b-up-front)
## The Sanofi acquisition, by the numbers
On 22 July 2025 Sanofi agreed to acquire all of Vicebio's share capital for a total upfront payment of $1.15 billion, with potential milestone payments of up to $450 million based on development and regulatory achievements, a total potential value of $1.6 billion; closing was expected in Q4 2025.[1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150) • [7](https://www.prnewswire.com/news-releases/vicebio-next-generation-vaccine-biotech-to-be-acquired-by-sanofi-for-us1-6-billion-302510454.html) Sanofi completed the acquisition on 4 December 2025, in line with that timeline.[2](https://www.sanofi.com/en/media-room/press-releases/2025/2025-12-04-10-00-00-3199555) A SEC-filed exhibit confirmed the deal brought an early-stage combination RSV/HMPV vaccine candidate and expanded Sanofi's vaccine design and development capabilities with the Molecular Clamp technology.[8](https://www.sec.gov/Archives/edgar/data/1121404/000119312525317248/d593009dex991.htm)
Sanofi's stated rationale was portfolio fit rather than near-term revenue. The company said the acquisition enables it to offer increased physician and patient choice in RSV and HMPV by adding a non-mRNA vaccine to its pipeline.[2](https://www.sanofi.com/en/media-room/press-releases/2025/2025-12-04-10-00-00-3199555) Endpoints framed Vicebio as taking on the approved RSV shots from GSK and Pfizer and Moderna's RSV program, differentiating through prefilled-syringe liquid combination vaccines.[4](https://endpoints.news/uk-vaccine-startup-vicebio-snags-100m-to-take-on-gsk-pfizer-and-moderna/)
## Context: UK biotech exits, 2023–2025
The Vicebio deal followed a closely parallel transaction. When [AstraZeneca](https://www.edgepedia.org/astrazeneca) paid $838 million upfront for [Icosavax](https://www.edgepedia.org/icosavax) in December 2023, it also acquired a clinical-stage bivalent vaccine for RSV and hMPV.[3](https://endpoints.news/sanofi-to-buy-early-stage-vaccine-maker-vicebio-for-1-15b-upfront/) Vicebio's trajectory, from a September 2024 Series B to a July 2025 takeout, illustrates how quickly a favorable first-in-human readout can convert a private vaccine startup into an acquisition target.[5](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html) • [1](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150)
## References
1. [Sanofi press release: Sanofi to acquire Vicebio, expanding respiratory vaccines pipeline](https://www.sanofi.com/en/media-room/press-releases/2025/2025-07-22-05-30-00-3119150)
2. [Sanofi press release: Sanofi completes acquisition of Vicebio](https://www.sanofi.com/en/media-room/press-releases/2025/2025-12-04-10-00-00-3199555)
3. [Endpoints News: Sanofi to buy early-stage vaccine maker Vicebio for $1.15B upfront](https://endpoints.news/sanofi-to-buy-early-stage-vaccine-maker-vicebio-for-1-15b-upfront/)
4. [Endpoints News: UK vaccine startup Vicebio snags $100M to take on GSK, Pfizer and Moderna](https://endpoints.news/uk-vaccine-startup-vicebio-snags-100m-to-take-on-gsk-pfizer-and-moderna/)
5. [PR Newswire: Vicebio Announces $100 Million Series B Financing and Initiation of Phase 1 Clinical Study of RSV/hMPV Bivalent Vaccine](https://www.prnewswire.com/news-releases/vicebio-announces-100-million-series-b-financing-and-initiation-of-phase-1-clinical-study-of-rsvhmpv-bivalent-vaccine-302254783.html)
6. [Goldman Sachs Asset Management: Sanofi to acquire next-generation vaccine biotech Vicebio for US $1.6 billion](https://am.gs.com/en-au/advisors/news/press-release/2025/vicebio)
7. [PR Newswire: Vicebio, next-generation vaccine biotech, to be acquired by Sanofi for US$1.6 billion](https://www.prnewswire.com/news-releases/vicebio-next-generation-vaccine-biotech-to-be-acquired-by-sanofi-for-us1-6-billion-302510454.html)
8. [SEC EDGAR: EX-99.1, Sanofi filing exhibit on Vicebio acquisition](https://www.sec.gov/Archives/edgar/data/1121404/000119312525317248/d593009dex991.htm)
9. [BioCentury: First clinical evidence spurs Sanofi's takeout of Vicebio for $1.15B up front](https://www.biocentury.com/article/656546/first-clinical-evidence-spurs-sanofi-s-takeout-of-vicebio-for-1-15b-up-front)
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*Topic: Encyclopedia › Society and history › Economics and business › Business and work › Business and work overview › Companies and corporations › Venture-backed startups and growth companies › Health, biotech, and medtech startups › Biologics and antibody developers*
*Initially written Sep 17, 2026 · Edited: Oct 11, 2026; Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license