Company: SNY
Filing Date: 2025-07-18
Form Type: SC TO-T/A
Source: 0001193125-25-160629
Chunk: 3

Company: Sanofi
Filing Date: 2025-07-18
Form: SC TO-T/A
Chunk 3
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, without interest and subject to any withholding of taxes required by applicable legal requirements, other than Shares (i) held in the treasury of the Company or owned by the Company
or any direct or indirect wholly owned subsidiary of the Company, by Parent or any direct or indirect wholly owned subsidiary of Parent (other than Purchaser), or by stockholders of the Company who have properly exercised and perfected their
statutory rights of appraisal under Delaware law, or (ii) irrevocably accepted by Purchaser for purchase in the Offer.

Following the
Merger, the Shares will no longer be listed on the NASDAQ Global Select Market and will be deregistered under the Exchange Act.

SIGNATURES After due inquiry and to the best knowledge and belief of the undersigned, each of the undersigned certifies that the information set forth in this statement is true, complete and correct. Date: July 17, 2025

|     |     | Rothko Merger Sub, Inc. |     |                                            |
| By: |     | /s/ Michael J. Tolpa    |     |                                            |
|     |     | Name:                   |     | Michael J. Tolpa                           |
|     |     | Title:                  |     | President                                  |
|     |     | SANOFI                  |     |                                            |
| By: |     | /s/ Roy Papatheodorou   |     |                                            |
|     |     | Name:                   |     | Roy Papatheodorou                          |
|     |     | Title:                  |     | Executive Vice President, General Counsel  |
|     |     | Aventis Inc.            |     |                                            |
| By: |     | /s/ Jamie Haney         |     |                                            |
|     |     | Name:                   |     | Jamie Haney                                |
|     |     | Title:                  |     | Vice President, General Counsel, Secretary |