UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Item 1.

Security and Issuer

(a)

Name of Issuer:     REPROS THERAPEUTICS, INC.

(b)

Address of Issuer’s Principal Executive Offices:

2408 Timberloch Place Suite B-7
The Woodlands, TX 77380

(c)

Title of Class of Securities:  Common Stock

Item 2.

Identity and Background

(a)

Name of Person Filing:

See Item 1 of each cover page.

Pursuant to Rule 13d-1(a) of General Rules and Regulations under the Securities Exchange Act of 1934, as amended (the “Act”), the undersigned hereby file this Schedule 13D Statement (this “Schedule 13D”) on behalf of (i) Mark Lappe, (ii) Jon Faiz Kayyem, (iii) Efficacy Capital Ltd., a Bermuda limited liability company (“Efficacy Capital”), (iv) Efficacy Biotech Fund, L.P., a Delaware limited partnership (“EBF”), (v) Efficacy Biotech Fund Limited, a Bermuda Exempted Mutual Fund Company (“EBFL”), and (vi) Efficacy Biotech Master Fund Ltd., a Bermuda Exempted Mutual Fund Company (“EBMFL”) (collectively, the “Reporting Persons”).

(b)

Address of Principal Business Office or, if none, Residence:

11622 El Camino Real, Suite 100
San Diego, CA 92130

(c)

Mark Lappe is the Managing Partner of Efficacy Capital Ltd., the Investment Manager for the Reporting Persons and a member of the Board of Directors of the Issuer.  Jon Faiz Kayyem is a Managing Partner of Efficacy Capital Ltd., the Investment Manager for the Reporting Persons.

(d)

None of the Reporting Persons have, during the last five years, been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e)

The Reporting Persons have not, during the last five years, been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and have not been subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, Federal or State securities laws or finding any violation with respect to such laws.

(f)

Citizenship:

See Item 6 of each cover page.

Item 3.

Source and Amount of Funds or Other Consideration

All of the funds used to purchase the Common Stock were from the working capital of one or more of the Reporting Persons.

Item 4.

Purpose of Transaction

The acquisitions described in Item 5 were made for investment purposes.  The Reporting Persons do not

presently  have any plans or proposals which relate to or would result in any of the transactions described in Item 4 of Schedule 13D.

Item 5.

Interest in Securities of the Issuer

(a)

The Reporting Persons collectively own 4,124,110 shares of the Issuer’s Common Stock comprising 32.22% of the Issuer’s outstanding Common Stock.

(b)

Except for the option to purchase Common Stock held by Mark Lappe, described below, each of the Reporting Persons has sole voting power and sole dispositive power of zero shares of the Issuer’s Common Stock.  The Reporting Persons collectively have shared voting power of 4,124,110 shares of the Issuer’s Common Stock and shared dispositive power of 4,124,110 shares of the Issuer’s Common Stock, provided, however, that EBMFL does not have voting power or dispositive power of 321,900 shares held by FMG Special Opportunity Fund Ltd. and FMG Special Opportunity Fund Ltd. does not have voting power or dispositive power of 3,802,210 shares held by EBMFL. Mark Lappe holds an option to purchase 40,000 shares of the Issuer’s Common Stock, none of which have vested and will not vest within the next 60 days. Of the options to purchase Common Stock not yet vested and not vesting within the next 60 days, 25,582 are subject to the approval of the increase in the number of shares reserved for issuance under the Company’s 2000 Non-Employee Director Stock Option Plan at the next annual meeting of stockholders. Upon the vesting and exercise of the option, Mark Lappe would hold sole voting and dispositive power over the shares of Common Stock subject to the option.

(c)

The following transactions were effected during the past sixty days.

Reporting Person

Date of Transaction

Amount of
Securities Involved

Price per Share

Where and How
Effected

Efficacy Capital, Ltd.

October 2, 2008

1,846,154

$

6.50

Registered Direct Offer

Mark Lappe

September 29, 2008

40,000

$

6.08

Stock Option Grant

(exercise price)

(d)

No person other than the Reporting Persons has rights with respect to the economic or voting interests associated with the Shares.

(e)

Not applicable.

Item 6.

Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

In connection with the purchase of 1,846,154 shares of the Issuer’s Common Stock, Efficacy Capital entered into a Common Stock Purchase Agreement, dated as of September 29, 2008, by and between Efficacy Capital and the Issuer (the “Purchase Agreement”).  The Purchase Agreement provides that the Reporting Persons shall have a right of first refusal with respect to any equity securities sold by Issuer from September 29, 2008 through September 29, 2010, up to the Reporting Persons’ pro rata share.

In addition, pursuant to the Purchase Agreement, the Reporting Persons have the option to acquire a number of shares of Issuer’s Common Stock with an aggregate value of up to $7,500,000 at the greater of (a) the Fair Market Value (as defined in the Purchase Agreement) at the time of exercise or (b) $7.80 per share (the “Purchase Option”).  The Purchase Option becomes exercisable at such time as the Issuer has less than $10 million in cash and cash equivalents and expires on September 29, 2009.

In connection with certain of the transactions described herein, Efficacy Capital entered into an Investment Advisory Agreement, dated as of May 7, 2006, by and between Efficacy Capital and FMG Special Opportunity Fund Ltd. (“the FMG Agreement”).  The FMG Agreement permits Efficacy Capital to purchase, sell, and vote Shares, and to give proxies for Shares, on behalf of FMG Special Opportunity Fund Ltd.

The Reporting Person and the Issuer are parties to a Standstill Agreement dated January 9, 2008, as amended by the First Amendment to Standstill Agreement, dated as of July 28, 2008 (the “First Amendment”) and the Second Amendment to Standstill Agreement, dated as of October 2, 2008 (the “Second Amendment”),

pursuant to which the Reporting Person agreed, among other things, that it would not (i) acquire shares of the Issuer’s common stock that would result in its aggregate beneficial ownership exceeding 40% of the outstanding shares of the Issuer’s common stock, (ii) participate in a “solicitation” or request for “proxies” to vote any securities of the Issuer, (iii) demand a meeting of the shareholders of the Issuer or nominate any person for election to the Board of Directors of the Issuer, subject to certain limited exceptions described below, (iv) communicate with any person or entity with respect to the voting of any the Issuer’s common stock, other than in accordance with the recommendations of a majority of the Issuer’s Board of Directors, (v) vote shares of the Issuer’s common stock in any manner other than in accordance with the recommendations of a majority of the Issuer’s Board of Directors who are not also officers or employees of the Issuer and not the director designated by Efficacy, or, if no such recommendation is made, in the same proportion as the votes cast by other holders of the Issuer’s common stock, (vi) make an offer to acquire the Issuer or cause such an offer to be made, with certain limited exceptions, (vii) otherwise seek to control the management or policies of the Issuer, (viii) for, join or in any way participate in a “group” with respect to any securities of the Issuer in connection with any action or matter otherwise prohibited under the Standstill Agreement, and (ix) transfer beneficial ownership of any shares of the Issuer’s common stock directly, or, knowingly, indirectly, to any person or group of persons who would after such sale beneficially or of record own more than 5% of the total outstanding shares of the Issuer’s common stock, with certain limited qualifications and exceptions.

The Standstill Agreement is filed as an Exhibit to the original Schedule 13D filed by the Reporting Persons on March 12, 2008.

Item 7.

Material to be Filed as Exhibits

Attached hereto as Exhibit 3 is the Purchase Agreement.

Attached hereto as Exhibit 4 is the First Amendment.

Attached hereto as Exhibit 5 is the Second Amendment.

Attached hereto as Exhibit 6 is the 2000 Non-Employee Director’s Stock Option Agreement.

October 6, 2008

Date

/s/ Mark Lappe

Mark Lappe

/s/ Jon Faiz Kayyem

Jon Faiz Kayyem

Efficacy Capital Ltd.,

a Bermuda limited liability company

/s/ Mark Lappe

By: Mark Lappe

Its: Managing Partner

Efficacy Biotech Fund, L.P.,

a Delaware limited partnership

By:  Efficacy Capital Ltd.

Its:  General Partner

/s/ Mark Lappe

By: Mark Lappe

Its: Managing Partner

Efficacy Biotech Fund Limited,

a Bermuda Exempted Mutual Fund Company

By:  Efficacy Capital Ltd.

Its:  Manager

/s/ Mark Lappe

By: Mark Lappe

Its: Managing Partner

Efficacy Biotech Master Fund Ltd.,

a Bermuda Exempted Mutual Fund Company

By:  Efficacy Capital Ltd.

Its:  Manager

/s/ Mark Lappe

By: Mark Lappe

Its: Managing Partner