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): March 23, 2016

Sagent Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Commission File Number: 1-35144

1901 N. Roselle Road, Suite 700, Schaumburg, Illinois 60195

(Address of principal executive offices, including zip code)

(847) 908-1600

(Registrant’s telephone number, including area code)

(Former name or former address, if changed since last report)

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:

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

On March 23, 2016, Sagent Pharmaceuticals, Inc. (the “Company”) announced that Sean Brynjelsen had been appointed to the newly created role of Executive Vice President, Business Development, effective April 4, 2016.

Mr. Brynjelsen, 44, has served most recently as Senior Vice President, Global Business Development of Akorn Inc., which he joined in 2007 as their Director of New Business Development. Prior to joining Akorn, Mr. Brynjelsen held roles of increasing responsibility at Hospira International and Baxter Healthcare Corporation. He earned a master’s degree in business administration from the University of Notre Dame and holds a bachelor’s degree of science in biochemistry and a master’s degree in science from the University of Illinois.

Mr. Brynjelsen was not selected pursuant to any arrangement or understanding between him and any other person. Mr. Brynjelsen has no family relationships with any of the Company’s directors or executive officers. There have been no related person transactions between Sagent and Mr. Brynjelsen reportable under Item 404(a) of Regulation S-K.

Pursuant to the Company’s employment agreement with Mr. Brynjelsen, (the “Employment Agreement”), Mr. Brynjelsen will be entitled to an annual base salary of $315,000. He will also be eligible to participate in the Company’s annual bonus program. Mr. Brynjelsen’s annual target award opportunity under the annual bonus program is equal to 40% of his salary, or $126,000 (pro-rated) in 2016. He will also receive an initial grant of stock options and restricted stock, each in the amount of approximately $120,000 and totaling $240,000 in aggregate, with each grant vesting over a four-year period in the amount of 25% annually on the anniversary of the grant date. Mr. Brynjelsen is also eligible for other benefits consistent with those received by the Company’s other executives.

Item 8.01 Other Events

On March 23, 2016, the Company issued a press release announcing the appointment described in Item 5.02 above. A copy of that press release is furnished herewith as Exhibit 99.1.

Item 9.01. Financial Statements and Exhibits.

(d) The following exhibit is being furnished with this Current Report on Form 8-K.

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.