|  ☐ |  | Preliminary Proxy Statement | 
|  ☐ |  | Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) | 
|  ☐ |  | Definitive Proxy Statement | 
|  ☒ |  | Definitive Additional Materials  | 
|  ☐ |  | Soliciting Material Pursuant to § 240.14a-12 | 
| Rigel Pharmaceuticals, Inc. | 
| (Name of Registrant as Specified In Its Charter) | 
|  | 
| (Name of Person(s) Filing Proxy Statement if Other Than the Registrant) | 
|  ☒ |  |  No fee required. | |
|  ☐ |  | Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11. | |
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|  |  |  | Aggregate number of securities to which transaction applies: | 
|  |  |  | Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (Set forth the amount on which the filing fee is calculated and state how it was determined): | 
|  |  |  | Proposed maximum aggregate value of transaction: | 
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|  | Date Filed: | 
 
        