UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 8, 2011

6166 Nancy Ridge Drive, San Diego, California 92121

858.453.7200

N/A

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

[ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

In this report, “Arena Pharmaceuticals,” “Arena,” “Company,” “we,” “us” and “our” refer to Arena Pharmaceuticals, Inc., unless the context otherwise provides.

Item 1.01 Entry into a Material Definitive Agreement.

On November 8, 2011, we entered into what is sometimes termed an equity line of credit arrangement with Azimuth Opportunity, L.P., or Azimuth. Specifically, we entered into a Common Stock Purchase Agreement, or the Purchase Agreement, that provides that, upon the terms and subject to the conditions set forth therein, Azimuth is committed to purchase up to $50 million worth of shares of our common stock over the 24-month term of the Purchase Agreement; provided, however, that, except as otherwise provided in the Purchase Agreement, in no event may we sell under the Purchase Agreement (i) more than 29,204,965 shares of our common stock, which is equal to one share less than twenty percent of our outstanding shares of common stock on the effective date of the Purchase Agreement, or (ii) a number of shares that would result in us breaching our obligations under the rules and regulations of the NASDAQ Global Select Market or would require us to obtain stockholder approval. From time to time over the term of the Purchase Agreement, and at our sole discretion, we may present Azimuth with draw down notices to purchase our common stock over ten consecutive trading days or such other period mutually agreed upon by us and Azimuth, or the draw down period, with each draw down subject to limitations based on the price of our common stock at the time of such draw down. We are able to present Azimuth with up to 24 draw down notices during the term of the Purchase Agreement, with only one such draw down notice allowed per draw down period and a minimum of five trading days required between each draw down period.

Once presented with a draw down notice, Azimuth is required to purchase a pro rata portion of the dollar amount of the shares specified in the notice on each trading day during the pricing period on which the daily volume weighted average price for our common stock exceeds a threshold price determined by us for such draw down. The per share purchase price for these shares will equal the daily volume weighted average price of our common stock on each date during the draw down period on which shares are purchased, less a discount ranging from 3.25% to 6.50%, based on the trading price of our common stock. If the daily volume weighted average price of our common stock falls below the threshold price on any trading day during a draw down period, the Purchase Agreement provides that Azimuth will not be required to purchase the pro rata portion of shares of common stock allocated to that day. However, at its election, Azimuth may buy the pro rata portion of shares allocated to that day at the threshold price less the discount described above.

The Purchase Agreement also provides that, from time to time and at our sole discretion, we may grant Azimuth the right to exercise one or more options to purchase additional shares of our common stock during each draw down period for an amount of shares specified by us based on the trading price of our common stock. Upon Azimuth’s exercise of an option, we would sell to Azimuth the shares of our common stock subject to the option at a price equal to the greater of the daily volume weighted average price of our common stock on the day Azimuth notifies us of its election to exercise its option or the threshold price for the option determined by us, less a discount calculated in the same manner as it is calculated in the draw down notices.

In addition to our issuance of shares of common stock to Azimuth pursuant to the Purchase Agreement, our Registration Statement on Form S-3 (File No. 333-166481) also covers the sale

of those shares from time to time by Azimuth to the public. Azimuth is an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act of 1933, as amended (the “Securities Act”).

We have agreed to indemnify and hold harmless Azimuth, its affiliates, employees, representatives and advisors and each person who controls Azimuth against certain liabilities, including certain liabilities related to violations of securities laws and rules and regulations of the NASDAQ Global Select Market. We have agreed to pay up to $35,000 of Azimuth’s reasonable attorneys’ fees and expenses (exclusive of disbursements and out-of-pocket expenses) incurred by Azimuth in connection with the preparation, negotiation, execution and delivery of the Purchase Agreement and related transaction documentation and legal due diligence. Further, if we issue a draw down notice and fail to deliver the shares to Azimuth on the applicable settlement date, and such failure continues for ten trading days, we have agreed to pay Azimuth liquidated damages in cash or restricted shares of our common stock, at Azimuth’s option.

Azimuth has agreed to indemnify and hold harmless us and each of our directors, officers and persons who control us against certain liabilities, including certain liabilities under the Securities Act that may be based upon written information furnished by Azimuth to us for inclusion in a prospectus or prospectus supplement related to this transaction.

Upon each sale of our common stock to Azimuth under the Purchase Agreement, we have also agreed to pay Reedland Capital Partners, an Institutional Division of Financial West Group, or Reedland, a placement fee equal to 0.75% of the aggregate dollar amount of common stock purchased by Azimuth. We have agreed to indemnify and hold harmless Reedland against certain liabilities, including certain liabilities under the Securities Act.

The foregoing descriptions are qualified in their entirety by reference to the Purchase Agreement, a copy of which is attached hereto as Exhibit 10.1.

Item 9.01 Financial Statements and Exhibits.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX