UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549 

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 3)* 

Juno Therapeutics, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value

(Title of Class of Securities)

48205A109

(CUSIP Number)

Robert J. Hugin

Executive Chairman

Celgene Corporation

86 Morris Avenue

Summit, New Jersey 07901

(908) 673-9000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

March 28, 2016

(Date of Event Which Requires Filing of This Statement) 

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g) check the following box:  ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).  

SCHEDULE 13D

CUSIP No. 48205A109

This Amendment No. 3 amends the Schedule 13D (the “Schedule 13D”) filed with the Securities and Exchange Commission (the “Commission”) on July 8, 2015, as amended by Amendment No. 1 filed with the Commission on August 4, 2015, and Amendment No. 2 filed with the Commission on December 21, 2015, with respect to common stock, par value $0.0001 per share (“Common Stock”), of Juno Therapeutics, Inc., a Delaware corporation (“Juno”). Capitalized terms used, but not defined herein, have the meanings ascribed to them in the Schedule 13D.

No modification.

Item 2 is hereby amended and supplemented by adding the Schedule A hereto. During the past five years, none of the Reporting Persons, nor, to the knowledge of the Reporting Persons, any of the persons listed on Schedule A hereto, has been (i) convicted in a criminal proceeding (excluding traffic violations and similar misdemeanors), or (ii) a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Item 3 is hereby amended and supplemented by adding the following:

Celgene Switzerland made the March 2016 Purchase (as defined in Item 4) with working capital of Celgene Switzerland set aside for the general purpose of investing.

Item 4 is hereby amended and supplemented by adding the following:

March 2016 Purchase

On March 28, 2016, Celgene Switzerland purchased an aggregate of 1,137,593 shares of Common Stock from Juno for an aggregate purchase price of approximately $46,999,996, or approximately $41.32 per share, for investment purposes (the “March 2016 Purchase”). The March 2016 Purchase was effected under section 2.3(a) of the Purchase Agreement, which is described under “Share Purchase Agreement—First Period Top-Up Rights” in this Item 4.

Item 5(a)-(c) is hereby amended and restated as follows:

(a)-(b) The information contained on the cover pages of this Schedule 13D are incorporated herein by reference.

(c) The information contained in Item 4 under “March 2016 Purchase” is incorporated herein by reference. Celgene also acquired beneficial ownership of an additional 1,137,593 shares of Common Stock due to the March 2016 Purchase.

No modification.

No modification.

SIGNATURE

After reasonable inquiry and to the best of its knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct.

SCHEDULE A

Name, business address, present principal occupation or employment and place of citizenship of the directors
and executive officers of the Reporting Persons

The name, business address and present principal occupation or employment of each of the directors and executive officers of the Reporting Persons are set forth below. The business address of each director and executive officer is c/o 86 Morris Avenue, Summit, New Jersey 07901. Unless otherwise indicated, each director and executive officer is a citizen of the United States.

CELGENE CORPORATION — BOARD OF DIRECTORS

CELGENE CORPORATION — EXECUTIVE OFFICERS

CELGENE SWITZERLAND LLC