UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

Current Report Filed Pursuant to Section 13 or 15(d) of

The Securities Exchange Act of 1934

Date of Report

(Date of earliest event reported): September 11, 2017

Repros Therapeutics Inc.

(Exact name of registrant as specified in its charter)

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):

¨   Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨   Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨   Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨   Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

The information in this Current Report is being furnished pursuant to Item 7.01 of Form 8-K and, according to general instruction B.2. thereunder, the information in this Current Report shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section. The information in this Current Report shall not be incorporated by reference into any registration statement pursuant to the Securities Act of 1933, as amended.

Representatives of Repros Therapeutics Inc., a Delaware corporation (the “Company”) are presenting updates on the Company’s Proellex® and Enclomiphene clinical programs to various investors and other interested parties September 11 through September 13, 2017, in New York, NY, using slides containing the information attached to this Current Report on Form 8-K as Exhibit 99.1. These slides contain statements that are “forward-looking statements” subject to the cautionary statement about forward-looking statements set forth therein.

SIGNATURES

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

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