UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K/A

Amendment No. 1

CURRENT REPORT

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): June 18, 2013

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))

Item 5.07  Submission of Matters to a Vote of Security Holders.

On June 21, 2013, Repros Therapeutics Inc. (the “Company”) filed with the Securities and Exchange Commission (the “SEC”) its original Current Report on Form 8-K (the “Original Form 8-K”) to report the results of the Annual Meeting held on June 18, 2013. As part of the Annual Meeting, the stockholders recommended, in a non-binding advisory vote, that a stockholder vote to approve the compensation paid to our named executive officers should occur every year.

This Amendment No. 1 to the Original Form 8-K is being filed by the Company to report that, in light of the voting results with respect to the frequency of shareholder votes on executive compensation, the Board of Directors has decided that the Company will hold an annual advisory vote on the compensation of named executive officers until the next required vote on the frequency of shareholder votes on the compensation of executives. The Company is required to hold votes on frequency every six years.

Except as described above and set forth herein, no modifications have been made to information contained in the Original Form 8-K, and the Company has not updated any information contained therein to reflect events that have occurred since the date of the Original Form 8-K. Accordingly, this Amendment No. 1 should be read in conjunction with the Original Form 8-K.

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.