[To be separately provided to the Investor]

Exhibit 10.1

Catalyst Pharmaceutical Partners, Inc.

355 Alhambra Circle, Suite 1500

Coral Gables, Florida 33134

Gentlemen:

The undersigned (the “Investor”) hereby confirms its agreement with Catalyst Pharmaceutical Partners, Inc., a Delaware corporation (the “Company”), as follows:

1. This Subscription Agreement, including the Terms and Conditions For Purchase of Shares attached hereto as Annex I (collectively, (this “Agreement”) is made as of the date set forth below between the Company and the Investor.

2. The Company has authorized the sale and issuance to certain investors of up to an aggregate of 8,800,000 shares (the “Shares”) of its common stock, par value $0.001 per share (the “Common Stock”) at an aggregate initial public offering price of $1.72 (the “Purchase Price”).

3. The offering and sale of the Shares (the “Offering”) are being made pursuant to (1) an effective Registration Statement on Form S-3, File No. 333-170945 (the “Registration Statement”) filed by the Company with the Securities and Exchange Commission (the “Commission”) (including the prospectus contained therein (the “Base Prospectus”), (2) if applicable, certain “free writing prospectuses” (as that term is defined in Rule 405 under the Securities Act of 1933, as amended (the “Securities Act”)), that have been or will be filed with the Commission and delivered to the Investor on or prior to the date hereof (the “Issuer Free Writing Prospectus”), containing certain supplemental information regarding the Shares, the terms of the Offering and the Company and (3) a Prospectus Supplement (the “Prospectus Supplement” and together with the Base Prospectus, the “Prospectus”) containing certain supplemental information regarding the Shares and terms of the Offering that has been or will be filed with the Commission and delivered to the Investor (or made available to the Investor by the filing by the Company of an electronic version thereof with the Commission).

4. The Company and the Investor agree that the Investor will purchase from the Company and the Company will issue and sell to the Investor the Shares set forth below for the aggregate Purchase Price set forth below. The Shares shall be purchased pursuant to the Terms and Conditions for Purchase of Shares attached hereto as Annex I and incorporated herein by this reference as if fully set forth herein. The Investor acknowledges that the Offering is not being underwritten by the placement agent (the “Placement Agent”) named in the Prospectus Supplement and that there is no minimum offering amount.

5. The manner of settlement of the Shares purchased by the Investor shall be determined by such Investor as follows (check one):

[To be separately provided to the Investor]

IT IS THE INVESTOR’S RESPONSIBILITY TO (A) MAKE THE NECESSARY WIRE TRANSFER OR CONFIRM THE PROPER ACCOUNT BALANCE IN A TIMELY MANNER AND (B) ARRANGE FOR SETTLEMENT BY WAY OF DWAC OR DVP IN A TIMELY MANNER. IF THE INVESTOR DOES NOT DELIVER THE AGGREGATE PURCHASE PRICE FOR THE SHARES OR DOES NOT MAKE PROPER ARRANGEMENTS FOR SETTLEMENT IN A TIMELY MANNER, THE SHARES MAY NOT BE DELIVERED AT CLOSING TO THE INVESTOR OR THE INVESTOR MAY BE EXCLUDED FROM THE CLOSING ALTOGETHER.

6. The Investor represents that, except as set forth below, (a) it has had no position, office or other material relationship within the past three years with the Company or persons known to it to be affiliates of the Company, (b) it is not a member of the Financial Industry Regulatory Authority, Inc. (“FINRA”) or an Associated Person (as such term is defined under the FINRA’s NASD Membership and Registration Rules Section 1011) as of the Closing, and (c) neither the Investor nor any group of Investors (as identified in a public filing made with the Commission) of which the Investor is a part in connection with the Offering, acquired, or obtained the right to acquire, 17.5% or more of the Common Stock (or securities convertible into or exercisable for Common Stock) or the voting power of the Company on a post-transaction basis. Exceptions:

(If no exceptions, write “none.” If left blank, response will be deemed to be “none.”)

7. The Investor represents that it has received (or otherwise had made available to it by the filing by the Company of an electronic version thereof with the Commission) the Base Prospectus, dated December 15, 2010, which is a part of the Company’s Registration Statement, the documents incorporated by reference therein and any free writing prospectus (collectively, the “Disclosure Package”), prior to or in connection with the receipt of this Agreement. The Investor acknowledges that, prior to the delivery of this Agreement to the Company, the Investor will receive certain additional information regarding the Offering, including pricing information (the “Offering Information”). Such information may be provided to the Investor by any means permitted under the Securities Act, including the Prospectus Supplement, a free writing prospectus and oral communications.

8. No offer by the Investor to buy Shares will be accepted and no part of the Purchase Price will be delivered to the Company until the Investor has received the Offering Information and the Company has accepted such offer by countersigning a copy of this Agreement, and any such offer may be withdrawn or revoked, without obligation or commitment of any kind, at any time prior to the Company (or Roth on behalf of the Company) sending (orally, in writing or by electronic mail) notice of its acceptance of such offer. An indication of interest will involve no obligation or commitment of any kind until the Investor has been delivered the Offering Information and this Agreement is accepted and countersigned by or on behalf of the Company.

9. The Company acknowledges that the only material, non-public information relating to the Company or its subsidiaries that the Company, its employees or agents has provided to the Investor in connection with the Offering prior to the date hereof is the existence of the Offering.

Please confirm that the foregoing correctly sets forth the agreement between us by signing in the space provided below for that purpose.

Agreed and Accepted

this 5^th day of September, 2013:

ANNEX I

TERMS AND CONDITIONS FOR PURCHASE OF SHARES

1. Authorization and Sale of the Shares. Subject to the terms and conditions of this Agreement, the Company has authorized the sale of the Shares.

2. Agreement to Sell and Purchase the Shares; Placement Agent.

2.1 At the Closing (as defined in Section 3.1), the Company will sell to the Investor, and the Investor will purchase from the Company, upon the terms and conditions set forth herein, the number of Shares set forth on the last page of the Agreement to which these Terms and Conditions for Purchase of Shares are attached as Annex I (the “Signature Page”) for the aggregate purchase price therefor set forth on the Signature Page.

2.2 The Company proposes to enter into substantially this same form of Subscription Agreement with certain other investors (the “Other Investors”) and expects to complete sales of Shares to them. The Investor and the Other Investors are hereinafter sometimes collectively referred to as the “Investors,” and this Agreement and the Subscription Agreements executed by the Other Investors are hereinafter sometimes collectively referred to as the “Agreements.”

2.3 Investor acknowledges that the Company has agreed to pay Roth Capital Partners, LLC (the “Placement Agent”) a fee (the “Placement Fee”) and to reimburse the Placement Agent for certain expenses in respect of the sale of the Shares to the Investor.

2.4 The Company has entered into a Placement Agency Agreement, dated the date hereof, (the “Placement Agreement”), with the Placement Agent that contains certain representations, warranties, covenants and agreements of the Company that may be relied upon by the Investor, which shall be a third party beneficiary thereof. The Company confirms that neither it nor any other Person acting on its behalf has provided the Investor or their agents or counsel with any information that constitutes or could reasonably be expected to constitute material, nonpublic information, except as will be disclosed in the Prospectus and/or in the Company’s Form 8-K to be filed with the Commission in connection with the Offering. The Company understands and confirms that the Investor will rely on the foregoing representations in effecting transactions in securities of the Company.

3. Closings and Delivery of the Shares and Funds.

3.1 Closing. The completion of the purchase and sale of the Shares (the “Closing”) shall occur at a place and time (the “Closing Date”) to be specified by the Company and the Placement Agent, and of which the Investors will be notified in advance by the Placement Agent, in accordance with Rule 15c6-l promulgated under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). At the Closing, (a) the Company shall cause Continental Stock Transfer & Trust Company, the Company’s “Transfer Agent”, to deliver to the Investor the number of Shares set forth on the Signature Page registered in the name of the Investor or, if so indicated on the Investor Questionnaire attached hereto as Exhibit A, in the name of a nominee designated by the Investor, and (b) the aggregate purchase price for the Shares being purchased by the Investor will be delivered by or on behalf of the Investor to the Company by wire transfer against issuance of the Shares.

3.2 Conditions to the Obligations of the Parties.

(a) Conditions to the Company’s Obligations. The Company’s obligation to issue and sell the Shares to the Investor shall be subject to: (i) the receipt by the Company of the purchase price for the Shares being purchased hereunder as set forth on the Signature Page and (ii) the accuracy of the representations and warranties made by the Investor and the fulfillment of those undertakings of the Investor to be fulfilled prior to the Closing Date.

(b) Conditions to the Investor’s Obligations. The Investor’s obligation to purchase the Shares will be subject to the accuracy of the representations and warranties made by the Company and the fulfillment of those undertakings of the Company to be fulfilled prior to the Closing Date, including without limitation, those contained in the Placement Agreement, and to the condition that the Placement Agent shall not have: (a) terminated the Placement Agreement pursuant to the terms thereof or (b) determined that the conditions to the closing in the Placement Agreement have not been satisfied. The Investor’s obligations are expressly not conditioned on the purchase by any or all of the Other Investors of the Shares that they have agreed to purchase from the Company. The Investor understands and agrees that, in the event that the Placement Agent in its sole discretion determines that the conditions to closing in the Placement Agreement have not been satisfied or if the Placement Agreement may be terminated for any other reason permitted by such Placement Agreement, then the Placement Agent may, but shall not be obligated to, terminate such Agreement, which shall have the effect of terminating this Subscription Agreement pursuant to Section 14 below.

3.3 Delivery of Funds.

(a) DWAC Delivery. If the Investor elects to settle the Shares purchased by such Investor through DTC’s Deposit/Withdrawal at Custodian (“DWAC”) delivery system, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall remit by wire transfer the amount of funds equal to the aggregate purchase price for the Shares being purchased by the Investor to the following account designated by the Company:

[To be separately provided to the Investor]

(b) Delivery Versus Payment through The Depository Trust Company. If the Investor elects to settle the Shares purchased by such Investor by delivery versus payment through DTC, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall confirm that the account or accounts at the Placement Agent to be credited with the Shares being purchased by the Investor have a minimum balance equal to the aggregate purchase price for the Shares being purchased by the Investor.

3.4 Delivery of Shares.

(a) DWAC Delivery. If the Investor elects to settle the Shares purchased by such Investor through DTC’s DWAC delivery system, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall direct the

broker-dealer at which the account or accounts to be credited with the Shares being purchased by such Investor are maintained, which broker/dealer shall be a DTC participant, to set up a DWAC instructing the Transfer Agent to credit such account or accounts with the Shares. Such DWAC instruction shall indicate the settlement date for the deposit of the Shares, which date shall be provided to the Investor by the Placement Agent. Upon the closing of the Offering, the Company shall direct the Transfer Agent to credit the Investor’s account or accounts with the Shares pursuant to the information contained in the DWAC.

(b) Delivery Versus Payment through The Depository Trust Company. If the Investor elects to settle the Shares purchased by such Investor by delivery versus payment through DTC, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall notify the Placement Agent of the account or accounts at the Placement Agent to be credited with the Shares being purchased by such Investor. On the Closing Date, the Company shall deliver the Shares to the Investor through DTC directly to the account(s) at the Placement identified by Investor. Upon receipt of such Shares, the Placement Agent shall promptly electronically deliver such Shares to the Investor, and simultaneously therewith payment shall be made by the Placement Agent by wire transfer to the Company.

4. Representations, Warranties and Covenants of the Investor.

The Investor acknowledges, represents and warrants to, and agrees with, the Company and the Placement Agent that:

4.1 The Investor (a) is knowledgeable, sophisticated and experienced in making, and is qualified to make decisions with respect to, investments in securities presenting an investment decision like that involved in the purchase of the Shares, including investments in securities issued by the Company and investments in comparable companies, (b) has answered all questions on the Signature Page and the Investor Questionnaire and the answers thereto are true and correct as of the date hereof and will be true and correct as of the Closing Date and (c) in connection with its decision to purchase the Shares set forth on the Signature Page, has received and is relying only upon the Disclosure Package and the documents incorporated by reference therein and the Offering Information.

4.2 (a) No action has been or will be taken in any jurisdiction outside the United States by the Company or the Placement Agent that would permit an offering of the Shares, or possession or distribution of offering materials in connection with the issue of the Shares in any jurisdiction outside the United States where action for that purpose is required, (b) if the Investor is outside the United States, it will comply with all applicable laws and regulations in each foreign jurisdiction in which it purchases, offers, sells or delivers Shares or has in its possession or distributes any offering material, in all cases at its own expense and (c) the Placement Agent is not authorized to make and has not made any representation, disclosure or use of any information in connection with the issue, placement, purchase and sale of the Shares, except as set forth or incorporated by reference in the Base Prospectus, the Prospectus Supplement or any free writing prospectus.

4.3 (a) The Investor has full right, power, authority and capacity to enter into this Agreement and to consummate the transactions contemplated hereby and has taken all necessary action to authorize the execution, delivery and performance of this Agreement, and (b) this Agreement constitutes a valid and binding obligation of the Investor enforceable against the Investor in accordance with its terms, except as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ and contracting parties’ rights generally and except as enforceability may be subject to general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and except as to the enforceability of any rights to indemnification or contribution that may be violative of the public policy underlying any law, rule or regulation (including any federal or state securities law, rule or regulation).

4.4 The Investor understands that nothing in this Agreement, the Prospectus, the Disclosure Package, the Offering Information or any other materials presented to the Investor in connection with the purchase and sale of the Shares constitutes legal, tax or investment advice. The Investor has consulted such legal, tax and investment advisors and made such investigation as it, in its sole discretion, has deemed necessary or appropriate in connection with its purchase of Shares.

4.5 The Investor will maintain the confidentiality of all information acquired as a result of the transactions contemplated hereby prior to the public disclosure of that information by the Company in accordance with Section 13 of this Annex.

4.6 Since the time at which the Placement Agent first contacted such Investor about the Offering, the Investor has not disclosed any information regarding the Offering to any third parties (other than its legal, accounting and other advisors) and has not engaged in any purchases or sales of the securities of the Company (including, without limitation, any Short Sales (as defined herein) involving the Company’s securities). The Investor covenants that it will not engage in any purchases or sales of the securities of the Company (including Short Sales) prior to the time that the transactions contemplated by this Agreement are publicly disclosed. The Investor agrees that it will not use any of the Shares acquired pursuant to this Agreement to cover any short position in the Common Stock if doing so would be in violation of applicable securities laws. For purposes hereof, “Short Sales” include, without limitation, all “short sales” as defined in Rule 200 promulgated under Regulation SHO under the Exchange Act, whether or not against the box, and all types of direct and indirect stock pledges, forward sales contracts, options, puts, calls, short sales, swaps, “put equivalent positions” (as defined in Rule 16a-1(h) under the Exchange Act) and similar arrangements (including on a total return basis), and sales and other transactions through non-U.S. broker dealers or foreign regulated brokers.

5. Survival of Representations, Warranties and Agreements; Third Party Beneficiary. Notwithstanding any investigation made by any party to this Agreement or by the Placement Agent, all covenants, agreements, representations and warranties made by the Company and the Investor herein will survive the execution of this Agreement, the delivery to the Investor of the Shares being purchased and the payment therefor. The Placement Agent shall be a third party beneficiary with respect to the representations, warranties and agreements of the Investor in Section 4 hereof.

6. Notices. All notices, requests, consents and other communications hereunder will be in writing, will be mailed (a) if within the domestic United States by first-class registered or certified airmail, or nationally recognized overnight express courier, postage prepaid, or by facsimile or (b) if delivered from outside the United States, by International Federal Express or facsimile, and will be deemed given (i) if delivered by first-class registered or certified mail domestic, three business days after so mailed, (ii) if delivered by nationally recognized overnight carrier, one business day after so mailed, (iii) if delivered by International Federal Express, two business days after so mailed and (iv) if delivered by facsimile, upon electronic confirmation of receipt and will be delivered and addressed as follows:

(a) if to the Company, to:

Catalyst Pharmaceutical Partners, Inc.

355 Alhambra Circle, Suite 1500

Coral Gables, Florida 33134

Attention: Patrick J. McEnany, Chairman, President and Chief Executive Officer

Fax: (305)  ###-###-####

with a copy (which shall not constitute notice) to:

Akerman Senterfitt

One Southeast Third Avenue, Suite 2500

Miami, Florida 33131

Attention: Philip B. Schwartz

Fax: (305)  ###-###-####

(b) if to the Investor, at its address on the Signature Page hereto, or at such other address or addresses as may have been furnished to the Company in writing.

7. Changes. This Agreement may not be modified or amended except pursuant to an instrument in writing signed by the Company and the Investor.

8. Headings. The headings of the various sections of this Agreement have been inserted for convenience of reference only and will not be deemed to be part of this Agreement.

9. Severability. In case any provision contained in this Agreement should be invalid, illegal or unenforceable in any respect, the validity, legality and enforceability of the remaining provisions contained herein will not in any way be affected or impaired thereby.

10. Governing Law. This Agreement will be governed by, and construed in accordance with, the internal laws of the State of New York, without giving effect to the principles of conflicts of law that would require the application of the laws of any other jurisdiction.

11. Counterparts. This Agreement may be executed in two or more counterparts, each of which will constitute an original, but all of which, when taken together, will constitute but one instrument, and will become effective when one or more counterparts have been signed by each party hereto and delivered to the other parties. The Company and the Investor acknowledge and agree that the Company shall deliver its counterpart to the Investor along with the Prospectus Supplement (or the filing by the Company of an electronic version thereof with the Commission).

12. Confirmation of Sale. The Investor acknowledges and agrees that such Investor’s receipt of the Company’s signed counterpart to this Agreement, together with the Prospectus Supplement (or the filing by the Company of an electronic version thereof with the Commission), shall constitute written confirmation of the Company’s sale of the Shares to such Investor.

13. Press Release. The Company and the Investor agree that the Company shall (a) prior to the opening of the financial markets in New York City on September 5, 2013 issue a press release announcing the Offering and disclosing all material information regarding the Offering and (b) as promptly as practicable on September 5, 2013 file a current report on Form 8-K with the Securities and Exchange Commission including, but not limited to, a form of this Agreement as an exhibit thereto.

14. Termination. In the event that the Placement Agreement is terminated by the Placement Agent pursuant to the terms thereof, this Agreement shall terminate without any further action on the part of the parties hereto.

EXHIBIT A

CATALYST PHARMACEUTICAL PARTNERS, INC.

INVESTOR QUESTIONNAIRE

Pursuant to Section 3 of Annex I to the Agreement, please provide us with the following information: