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): August 1, 2016

INOTEK PHARMACEUTICALS CORPORATION

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (781) 676-2100

Not Applicable

(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:

On August 1, 2016, Inotek Pharmaceuticals Corporation (NASDAQ: ITEK) (the “Company”) filed with the U.S. Securities and Exchange Commission (the “SEC”) a preliminary prospectus supplement pursuant to Rule 424(b)(5) under the Securities Act of 1933, as amended, relating to our Registration Statement on Form S-3 (File No. 333-210585) in connection with a proposed public offering of convertible senior notes. In this preliminary prospectus supplement, the Company disclosed that as of June 30, 2016, the Company had estimated cash, cash equivalents and short-term investments of approximately $98.2 million. This reflects the Company’s estimates based solely upon information available to it as of the date of this Current Report on Form 8-K, is not a comprehensive statement of its financial results or positions as of or for the quarter ended June 30, 2016, and has not been audited or reviewed by the Company’s independent registered public accounting firm.

The information in this Item 2.02 shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended. The information contained in this Item 2.02 shall not be incorporated by reference into any registration statement or other document filed by the Company with the SEC, whether made before or after the date of this Current Report on Form 8-K, regardless of any general incorporation language in such filing (or any reference to this Current Report on Form 8-K generally), except as shall be expressly set forth by specific reference in such filing.

Forward Looking Statements

This Current Report on Form 8-K contains forward-looking statements that involve risks and uncertainties, such as statements related to its cash position as of June 30, 2016. The risks and uncertainties involved include without limitation, risks and uncertainties related to changes in estimated cash position based on the audit of the Company’s financial statements, as well as other risks detailed from time to time in the Company’s filings with the SEC. You are cautioned not to place undue reliance on forward-looking statements, which are based on the Company’s current expectations and assumptions and speak only as of the date of this report. The Company does not intend to revise or update any forward-looking statement in this report to reflect events or circumstances arising after the date hereof, except as may be required by law.

SIGNATURE

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.