Paris, France and Amsterdam, The Netherlands - Sanofi (Euronext: SAN and NYSE: SNY) and Kiadis (Euronext Amsterdam and Brussels: KDS) today jointly announce the successful completion of Sanofi's acquisition of Kiadis, a clinical-stage biopharmaceutical company developing next generation 'off-the-shelf' NK cell-therapies.

Kiadis' proprietary platform is based on allogeneic or 'off-the-shelf' NK-cells from a healthy donor. NK-cells seek and identify malignant cancer cells and have broad application across various tumor types. The platform has the potential to make products rapidly and economically available for a broad patient population across a wide range of liquid and solid tumors, and create synergies with Sanofi's immuno-oncology pipeline.

Kiadis' NK cell-based medicines will be developed alone and in combination with Sanofi's existing pipeline and platforms.

The acquisition continues to build on Sanofi's emerging presence in immuno-oncology aligned with the company's strategy to pursue best-in-class treatments in defined areas.

As of the Settlement, which has taken place today, Sanofi holds approximately 95.03% of the issued and outstanding share capital of Kiadis on a Fully Diluted basis.

Shareholders who have not yet tendered their Shares will have the opportunity to tender their Shares under the same terms and conditions applicable to the Offer, during the Post-Closing Acceptance Period which started on 14 April 2021 and will end at 17:40 (CET) on 28 April 2021. Sanofi intends to initiate the Buy-Out in an expeditious manner. Reference is made to the joint press release by Sanofi and Kiadis dated 13 April 2021.

Upon Settlement the changes to the composition of the Supervisory Board and Management Board of Kiadis, as approved by the EGM on 30 March 2021, will become effective.

Contact:

Kiadis

Maryann Cimino, Director Investor Relations & Corporate Affairs

Tel: +1 (617) 710 7305

E: m.cimino@kiadis.com

Kiadis Media

LifeSpring Life Sciences Communication:

Leon Melens (Amsterdam)

Tel: +31 (20) 538 16 427

E: lmelens@lifespring.nl

Optimum Strategic Communications

Mary Clark

Supriya Mathur

Tel: +44 (203) 950 9144

E: kiadis@optimumcomms.com

Sanofi

Sanofi Media

Ashleigh Koss

Tel: +1 (908) 205 2572

E: ashleigh.koss@sanofi.com

Sanofi Investor

Paris

Eva Schaefer-Jansen

Arnaud Delepine

Yvonne Naughton

Sanofi Investor

North America

Felix Lauscher

Fara Berkowitz

Suzanne Greco

Tel: +33 (1) 53 77 45 45

E: ir@sanofi.com

About Kiadis

Founded in 1997, Kiadis is committed to developing innovative cell-based medicines for patients with life-threatening diseases. With headquarters in Amsterdam, The Netherlands, and offices and activities across the United States, Kiadis is reimagining medicine by leveraging the natural strengths of humanity and our collective immune system to source the best cells for life.

Kiadis is listed on the regulated market of Euronext Amsterdam and Euronext Brussels since July 2, 2015, under the symbol KDS. Learn more at www.kiadis.com.

About Sanofi

Sanofi is dedicated to supporting people through their health challenges. It is a global biopharmaceutical company focused on human health. Sanofi prevents illness with vaccines and provides innovative treatments to fight pain and ease suffering. Sanofi stands by the few who suffer from rare diseases and the millions with long-term chronic conditions.

With more than 100,000 people in 100 countries, Sanofi is transforming scientific innovation into healthcare solutions around the globe.

Sanofi, Empowering Life.

Kiadis forward-looking statements

Certain statements, beliefs and opinions in this press release are forward-looking, which reflect Kiadis' or, as appropriate, Kiadis' officers' current expectations and projections about future events. By their nature, forward-looking statements involve a number of known and unknown risks, uncertainties and assumptions that could cause actual results, performance, achievements or events to differ materially from those expressed, anticipated or implied by the forward-looking statements. These risks, uncertainties and assumptions could adversely affect the outcome and financial effects of the plans and events described herein. A multitude of factors including, but not limited to, changes in demand, regulation, competition and technology, can cause actual events, performance, achievements or results to differ significantly from any anticipated or implied development. Forward-looking statements contained in this press release regarding past trends or activities should not be taken as a representation that such trends or activities will continue in the future. As a result, Kiadis expressly disclaims any obligation or undertaking to release any update or revisions to any forward-looking statements in this press release as a result of any change in expectations or projections, or any change in events, conditions, assumptions or circumstances on which these forward-looking statements are based. Neither Kiadis nor its advisers or representatives nor any of its subsidiary undertakings or any such person's officers or employees guarantees that the assumptions underlying such forward-looking statements are free from errors nor does either accept any responsibility for the future accuracy of the forward-looking statements contained in this press release or the actual occurrence of the anticipated or implied developments. You should not place undue reliance on forward-looking statements, which speak only as of the date of this press release.

Sanofi forward-looking statements

This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. These statements include projections and estimates and their underlying assumptions, statements regarding plans, objectives, intentions and expectations with respect to future financial results, events, operations, services, product development and potential, and statements regarding future performance. Forward-looking statements are generally identified by the words 'expects', 'anticipates', 'believes', 'intends', 'estimates', 'plans' and similar expressions. Although Sanofi's management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Sanofi, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include among other things, risks related to Sanofi's ability to complete the acquisition on the proposed terms or on the proposed timeline, the possibility that competing offers will be made, other risks associated with executing business combination transactions, such as the risk that the businesses will not be integrated successfully, that such integration may be more difficult, time-consuming or costly than expected or that the expected benefits of the acquisition will not be realized, the uncertainties inherent in research and development, future clinical data and analysis, including post marketing, decisions by regulatory authorities, such as the FDA or the EMA, regarding whether and when to approve any drug, device or biological application that may be filed for any such product candidates as well as their decisions regarding labelling and other matters that could affect the availability or commercial potential of such product candidates, the fact that product candidates if approved may not be commercially successful, the future approval and commercial success of therapeutic alternatives, Sanofi's ability to benefit from external growth opportunities, to complete related transactions and/or obtain regulatory clearances, risks associated with intellectual property and any related pending or future litigation and the ultimate outcome of such litigation, trends in exchange rates and prevailing interest rates, volatile economic and market conditions, cost containment initiatives and subsequent changes thereto, and the impact that COVID-19 will have on us, our customers, suppliers, vendors, and other business partners, and the financial condition of any one of them, as well as on our employees and on the global economy as a whole. Any material effect of COVID-19 on any of the foregoing could also adversely impact us. This situation is changing rapidly and additional impacts may arise of which we are not currently aware and may exacerbate other previously identified risks. The risks and uncertainties also include the uncertainties discussed or identified in the public filings with the SEC and the AMF made by Sanofi, including those listed under 'Risk Factors' and 'Cautionary Statement Regarding Forward-Looking Statements' in Sanofi's annual report on Form 20-F for the year ended December 31, 2019. Other than as required by applicable law, Sanofi does not undertake any obligation to update or revise any forward-looking information or statements.

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