X0305 4 2012-03-29 0001080709 ARENA PHARMACEUTICALS INC ARNA 0001514346 Bielasz Jennifer Kathleen C/O ARENA PHARMACEUTICALS, INC. 6166 NANCY RIDGE DRIVE SAN DIEGO CA 92121 0 1 0 0 Sr.Dir. of Acct. & Cont. (PAO) Common Stock 2012-03-29 4 M 0 6250 1.49 A 15600 D Common Stock 2012-03-29 4 S 0 6250 3.0401 D 9350 D Common Stock 2012-03-29 4 S 0 4550 3.0101 D 4800 D Common Stock 30 I By son Employee Stock Option (right to buy) 1.49 2012-03-29 4 M 0 6250 0 D 2021-03-15 Common Stock 6250 18750 D The reporting person paid the issuer a total of $34.20 for the difference between the $1.90 per share price of the 30 shares her son purchased on February 1, 2012, and the $3.0401 per share price of 30 of the shares sold by the reporting person and reported on this line. The options, representing the right to purchase a total of 25,000 shares, vest in four equal annual installments beginning on March 15, 2012, which was the first anniversary of the date on which the options were granted. The options are exercisable once vested. Adam S. Chinnock, as Attorney-in-Fact 2012-03-30