UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. )*

GLOBEIMMUNE, INC.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

37957B100

(CUSIP Number)

July 8, 2014

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

¨ Rule 13d-1(b)

x Rule 13d-1(c)

¨ Rule 13d-1(d)

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).

CUSIP No. 37957B100

CUSIP No. 37957B100

ITEM 1.

(A) NAME OF ISSUER:

GlobeImmune, Inc.

(B) ADDRESS OF ISSUER’S PRINCIPAL EXECUTIVE OFFICE:

1450 Infinite Drive, Louisville, Colorado 80027

ITEM 2.

(A) NAME OF PERSONS FILING:

Celgene International Inc. (“CII”)

Celgene Corporation (“Celgene”)

(B) ADDRESS OF PRINCIPAL BUSINESS OFFICE OR IF NONE, RESIDENCE:

86 Morris Avenue, Summit, New Jersey 07901

(C) CITIZENSHIP:

Delaware, U.S.A.

(D) TITLE OF CLASS OF SECURITIES:

Common Stock

(E) CUSIP NUMBER:

37957B100

ITEM 3. STATEMENT FILED PURSUANT TO RULE 13D-1(B) OR 13D-2(B) OR (C)

Not applicable.

ITEM 4. OWNERSHIP.

(a), (b) and (c) — The information contained on the cover pages to this Schedule 13G are incorporated herein by reference.

As of July 8, 2014, following the consummation of the Issuer’s initial public offering on such date, (i) CII shares beneficial ownership of 467,452 shares of Common Stock (including 66,782 shares of Common Stock underlying the Warrant), representing approximately 8.4% of the shares of Common Stock outstanding as of such date, (ii) Celgene shares beneficial ownership of 467,452 shares of Common Stock (including 66,782 shares of Common Stock underlying the Warrant), representing approximately 8.4% of the shares of Common Stock outstanding as of such date, and (iii) Celgene has sole beneficial ownership of 200,000 shares of Common Stock, representing approximately 3.6% of the shares of Common Stock outstanding as of such date.

ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS

Not applicable.

ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON

Not applicable.

ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY

Not applicable.

ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP

Not applicable.

ITEM 9. NOTICE OF DISSOLUTION OF GROUP

Not applicable.

ITEM 10. CERTIFICATION.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: July 9, 2014

EXHIBIT 1

JOINT FILING AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of shares of stock of GlobeImmune, Inc. The undersigned also agree that all subsequent amendments to this statement on Schedule 13G may be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements.

EXECUTED this July 9, 2014.