RIGEL PHARMACEUTICALS,INC. (NASDAQ:RIGL) Files An 8-K Results of Operations and Financial Condition
Item 2.02 Results of Operations and Financial Condition

On April18, 2018, Rigel Pharmaceuticals,Inc. filed a preliminary prospectus supplement with the U.S. Securities and Exchange Commission, or the SEC, to Rule424(b)(5), or the Prospectus Supplement,in which it disclosed that, although it has not finalized its financial statements for the quarter ended March31, 2018, it expects to report that it had approximately $94.3 million of cash, cash equivalents and short-term investments as of March31, 2018. We have not yet completed our quarter-end financial close process for the quarter ended March31, 2018. This estimate of our cash, cash equivalents and short-term investments as of March31, 2018 is preliminary, has not been audited and is subject to change upon completion of our financial statement closing procedures and the audit of our financial statements. Additional information and disclosure would be required for a more complete understanding of our financial position and results of operations as of March31, 2018.

Forward-Looking Statements

This Item 2.02 of this report contains forward-looking statements, including, without limitation, statements relating to our cash position as of March31, 2018. These forward-looking statements are based upon our current expectations. Actual results could differ materially from these forward-looking statements as a result of certain factors, including, without limitation, risks related to changes in estimated cash position based on the completion of our financial statement closing procedures and the review by our independent registered public accounting firm of such financial statements, and other risks detailed in our filings with the U.S. Securities and Exchange Commission, or the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this report. We do not undertake any obligation to update any forward-looking statements as a result of new information, future events, changed assumptions or otherwise.

The information in Item 2.02 of this report shall not be deemed to be “filed” for purposes of Section18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section11 and 12(a)(2)of the Securities Act of 1933, as amended. The information contained herein shall not be incorporated by reference into any filing with the SEC made by us, whether made before or after the date hereof, regardless of any general incorporation language in such filing.

Item 8.01. Other Events.

On April19, 2018, we entered into an underwriting agreement, or the Underwriting Agreement, with Jefferies LLC and Piper Jaffray& Co., as the representatives of the several underwriters named therein, collectively, the Underwriters, relating to the public offering, issuance and sale of 16,000,000 shares of our common stock, par value $0.001 per share, or the Common Stock. The price to the public in this offering is $3.90 per share, and the Underwriters have agreed to purchase the shares from us to the Underwriting Agreement at a price of $3.666 per share. Under the terms of the Underwriting Agreement, we also granted the Underwriters an option exercisable for 30 days to purchase up to an additional 2,400,000 shares of Common Stock at the public offering price, less underwriting discounts and commissions. The offering is expected to close on April24, 2018, subject to customary closing conditions.

The Underwriting Agreement contains customary representations, warranties and agreements by the Company, customary conditions to closing, indemnification obligations of us and the Underwriters, including for liabilities under the Securities Act of 1933, as amended, other obligations of the parties and termination provisions. The representations, warranties and covenants contained in the Underwriting Agreement were made only for purposes of such agreement and as of specific dates, were solely for the benefit of the parties to such agreement, and may be subject to limitations agreed upon by the contracting parties, including being qualified by confidential disclosures exchanged between the parties in connection with the execution of the Underwriting Agreement.

The offering is being made to our effective registration statement on FormS-3 and an accompanying prospectus (Registration Statement No.333-223564) previously filed with the SEC and a preliminary and final prospectus supplement thereunder. The Underwriting Agreement is filed as Exhibit1.1 to this report, and the description of the material terms of the Underwriting Agreement is qualified in its entirety by reference to such exhibit. A copy of the opinion of Cooley LLP relating to the legality of the issuance and sale of the shares in the offering is attached as Exhibit5.1 hereto.

Additionally, the Company is supplementing and updating certain aspects of the description of its business from that described under the heading, “Item 1. Business” in the Company’s Annual Report on Form10-K for the year ended December31, 2017, filed with the SEC on March6, 2018. The updated Company disclosure is filed herewith as Exhibit99.1 and is incorporated herein by reference.