UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 20, 2015

Corbus Pharmaceuticals Holdings, Inc.

(Exact name of registrant as specified in its charter)

100 River Ridge Drive, Norwood, MA 02062

(Address of Principal Executive Offices) (Zip Code)

Registrant’s telephone number, including area code: (617) 963-0100

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

On April 20, 2015, Corbus Pharmaceuticals Holdings, Inc. (the “Company”) entered into an award agreement with Cystic Fibrosis Foundation Therapeutics, Inc. (“CFFT”), a non-profit drug discovery and development affiliate of the Cystic Fibrosis Foundation, pursuant to which it received a development award (the “Award”) for up to $5 million in funding. The funding from the Award will help support a first-in-patient Phase 2 clinical trial of the Company’s oral anti-inflammatory drug Resunab in adults with cystic fibrosis (“CF”).

Upon the execution of the Award agreement, the Company is entitled to receive $1,250,000. The remainder of the Award will be paid to the Company incrementally upon the achievement of certain milestones related to the progress of the Phase 2 CF clinical trial, as set forth in the Award agreement. Pursuant to the terms of the Award agreement, the Company is obligated to make royalty payments to CFFT contingent upon commercialization of Resunab in the Field of Use (as defined in the Award agreement) including a royalty payment equal to five times the amount the Company receives under the Award agreement, up to $25 million, payable in three equal annual installments following the first commercial sale of Resunab, the first of which is due within 90 days following the first commercial sale of Resunab. The Company is also obligated to make a royalty payment to CFFT equal to the amount the Company receives under the Award agreement, up to $5 million, due in the first calendar year in which the aggregate cumulative net sales of Resunab in the Field of Use exceed $500 million. Lastly, the Company is obligated to make royalty payment(s) to CFFT of up to approximately $15 million if the Company transfers, sells or licenses Resunab in the Field of Use other than for certain clinical or development purposes, or if the Company enters into a change of control transaction, with such payment(s) to be credited against the royalty payments due upon commercialization. The Field of Use is defined in the Award as the treatment in humans of CF, asbestosis, bronchiectasis, byssinosis, chronic bronchitis/COPD hypersensitivity pneumonitis, pneumoconiosis, primary ciliary dyskinesis, sarcoidosis and silicosis. Either CFFT or the Company may terminate the agreement for cause, which includes the Company’s material failure to achieve certain commercialization and development milestones. The Company’s payment obligations survive the termination of the Award agreement.

As of April 20, 2015, the Award agreement constitutes a direct financial obligation of the Company, the material terms of which are described above under Item 1.01 and are incorporated herein by reference.

On April 22, 2015, the Company issued a press release dated April 22, 2015 announcing receipt of the Award, a copy of which is attached hereto as Exhibit 99.1.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX