Company: SNY
Filing Date: 2025-06-17
Form Type: SC TO-T
Source: 0001193125-25-141704
Chunk: 5

Company: Sanofi
Filing Date: 2025-06-17
Form: SC TO-T
Chunk 5
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 incorporated herein by reference:

| • |     | Section 8 – “Certain Information Concerning Parent, Aventis, Purchaser and Certain Related 
 Persons”                                                                                   |

4

| • |     | Section 10 – “Background of the Offer; Past Contacts or Negotiations with the Company” |

| • |     | Section 11 – “The Merger Agreement; The CVR Agreement; Other Agreements” |

| • |     | Section 12 – “Purpose of the Offer; Plans for the Company” |

(a)(2) The information set forth in the following sections of the Offer to Purchase is incorporated herein by reference:

| • |     | Section 12 – “Purpose of the Offer; Plans for the Company” |

| • |     | Section 15 – “Conditions of the Offer” |

| • |     | Section 16 – “Certain Legal Matters; Regulatory Approvals” |

(a)(3) The information set forth in the following sections of the Offer to Purchase is incorporated herein by reference:

| • |     | Section 15 – “Conditions of the Offer” |

| • |     | Section 16 – “Certain Legal Matters; Regulatory Approvals” |

(a)(4) The information set forth in the following sections of the Offer to Purchase is incorporated herein by reference:

| • |     | Section 13 – “Certain Effects of the Offer” |

(a)(5) The information set forth in the following sections of the Offer to Purchase is incorporated herein by reference:

| • |     | Section 16 – “Certain Legal Matters; Regulatory Approvals” |

(c) The information set forth in the Offer to Purchase is incorporated herein by reference. Item 12. Exhibits.

| Exhibit No. |     | Description                                                                                                        |
| (a)(1)(A)   |     | Offer to Purchase, dated June 17, 2025.*                                                                           |
| (a)(1)(B)   |     | Letter of Transmittal (including Guidelines for Certification of Taxpayer Identification Number on IRS Form W-9).* |
| (a)(1)(C)   |     | Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*                                 |
| (a)(1)(D)   |     | Letter to Clients for use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.*              |
| (a)(1)(E)   |     | Form of Notice of Guaranteed Delivery.*