Sanofi announced today that it has entered into an agreement to acquire Vigil Neuroscience, Inc. (“Vigil”), a publicly traded clinical-stage biotechnology company focused on developing novel therapies for neurodegenerative diseases. This acquisition in neurology, one of Sanofi’s four strategic disease areas, enhances Sanofi’s early-stage pipeline and includes VG-3927, which will be evaluated in a phase 2 clinical study in Alzheimer’s disease. VG-3927 is an
oral small molecule TREM2 agonist. Activating TREM2 is expected to enhance the neuroprotective
function of microglia in Alzheimer’s disease.

Houman Ashrafian, MD, PhD ,Head of Research and Development, Sanofi

“This acquisition is fully supporting Sanofi’s strategic focus on neurology and on advancing
science and leveraging our expertise in immunology to solve areas of critical unmet need. TREM2
represents a compelling target at the intersection of immune dysregulation and
neurodegeneration, particularly in people living with Alzheimer’s because they face devastating
cognitive decline with limited treatment options. Vigil’s expertise is complementary to our
capabilities in neurology and reinforces our dedication to developing innovative medicines to
improve people’s lives. Vigil’s team are a welcome addition, and we look forward to working with
them and the patient community.”

Ivana Magovčević-Liebisch, PhD, JD ,President & Chief Executive Officer, Vigil,

“We are incredibly proud of the extraordinary and diverse team at Vigil and the progress we have
made in developing innovative TREM2-based therapeutics. We look forward to joining forces
with Sanofi’s team to leverage Sanofi’s resources, broad platform and far-reaching network to
fully unlock and accelerate the development of VG-3927 for the potential treatment of Alzheimer’s
disease – a devastating disease with significant unmet need.”

In neurodegenerative diseases such as Alzheimer’s disease, microglial activation is dysregulated,
leading to debris accumulation, chronic inflammation and neurodegeneration in the central
nervous system. Activation of TREM2 has shown to promote the migration of microglial cells to
sites of injury, enhance their capability for phagocytosis, proliferation, and survival.
Consequently, this facilitates the prevention of neural degeneration that is frequently associated
with adult-onset neurodegenerative diseases.

Currently approved therapies for Alzheimer’s disease do not stop or reverse the disease
progression and there are stringent eligibility requirements for treatment. There is a critical need
to develop more efficacious, safer, and convenient options for people living with Alzheimer’s
disease.

In June 2024, Sanofi made a $40 million strategic investment in Vigil that included the exclusive
right of first negotiation for an exclusive license, grant, or transfer of rights to research, develop,
manufacture, and commercialize VG-3927. This acquisition is a testament to Sanofi’s proactive
approach in equity investments to secure greater optionality in addressing critical healthcare
challenges. By strategically investing in promising ventures like Vigil, Sanofi demonstrates how
its forward-looking strategies are translating into tangible advancements in the neurology
pipeline and reinforcing a commitment to innovation.

VGL101, Vigil’s second molecule program, is not being acquired by Sanofi.

Financial considerations
Under the terms of the merger agreement, Sanofi and Vigil have agreed to the following:

• Sanofi will acquire all outstanding common shares of Vigil for $8 per share in cash at closing,
  representing an equity value of approximately $470 million (on a fully diluted basis)
• In addition, Vigil’s shareholders will receive a non-transferrable contingent value right (CVR)
  per Vigil share, which will entitle its holder to receive a deferred cash payment of $2,
  conditioned upon the first commercial sale of VG-3927.

To demonstrate their commitment to the transaction, Bruce Booth, Atlas Ventures, and CEO
Ivana Magovčević-Liebisch have signed voting and support agreements in favor of the deal. The
shares subject to these agreements represent a total of approximately 16.2% of Vigil’s total
common shares outstanding.

The closing of the acquisition is subject to other conditions customary for such a transaction,
including the approval of holders of a majority of the outstanding shares of Vigil common stock,
the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, and other customary conditions.

The companies expect the transaction to close in Q3 2025. The acquisition will not have an
impact on Sanofi’s financial guidance for 2025.