X0306 4/A 2016-06-30 2016-07-01 0 0001594864 Juno Therapeutics, Inc. JUNO 0001480212 Bishop Hans Edgar C/O 307 WESTLAKE AVENUE N STE 300 SEATTLE WA 98109 1 1 0 0 CEO & President Common Stock 2016-06-30 4 M 0 44000 6.36 A 2657859 D Common Stock 2016-06-30 4 S 0 108894 38.4053 D 2548965 D Common Stock 2016-06-30 4 S 0 6356 39.177 D 2542609 D Stock Option (Right to Buy) 6.36 2016-06-30 4 M 0 44000 0.00 D 2024-09-08 Common Stock 44000 795506 D This Form 4/A is being filed solely to correct the transaction code used for the sales that were reported in the Form 4 filed by the reporting person on July 1, 2016. The transaction code was erroneously reported as "D" instead of as "S." The sales reported on this Form 4/A were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 17, 2016. This transaction was executed in multiple trades at prices ranging from $38.03 to $39.02. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $39.03 to $39.54. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. 1/48th of the shares subject to the option became vested and exercisable on October 9, 2014 and 1/48th of the shares subject to the option vested monthly thereafter. /s/ Zachary D. Hale, attorney-in-fact 2016-09-02