X0306 4 2020-11-25 0 0001080709 ARENA PHARMACEUTICALS INC ARNA 0001814928 Cabell Christopher C/O ARENA PHARMACEUTICALS, INC. 6154 NANCY RIDGE DRIVE SAN DIEGO CA 92121 0 1 0 0 EVP, Head of R&D, and CMO Common Stock 2020-11-25 4 M 0 2500 0.00 A 2500 D Common Stock 2020-11-25 4 F 0 1099 65.50 D 1401 D Performance Restricted Stock Unit 2020-11-25 4 M 0 2500 0.00 D 2022-01-03 Common Stock 2500 5000 D On January 4, 2019, the Reporting Person was granted 5,000 target Performance Restricted Stock Units ("PRSUs"). The PRSUs represented a contingent right to receive a number of shares of Arena's common stock equal to 50%, 100%, or 200% of the target PRSU amount. Such common shares vest, if at all, upon Arena's common stock reaching certain Nasdaq "Closing Price" thresholds during the 3-year performance period from Jan. 4, 2019, through Jan. 3, 2022 (the "Performance Period") and satisfaction of a subsequent continuing service requirement. 2,500 of the shares subject to the PRSUs vested in Oct. 2019 (50% of the target amount). On Nov. 25, 2020, another 2,500 of the shares subject to the PRSUs vested (50% of the target amount). The final Closing Price target has been met and an additional 5,000 shares will be issuable pursuant to the PRSUs (200% of the target amount, less the 100% already vested) if the Reporting Person satisfies the subsequent continuing service requirement. Represents the number of shares withheld by, and surrendered to, Arena relating to tax withholding in connection with the issuance of shares under the PRSUs. The amount reported in Column 7 of Table II represents the common shares that vested on November 25, 2020. The PRSUs' final Closing Price target has been met and the Reporting Person has a contingent right to receive 5,000 additional common shares if the subsequent continuing service requirement is met. /s/ Andrew J. Cronauer, as Attorney-in-Fact 2020-11-30