Catalyst Pharmaceuticals Announces First Quarter 2015 Financial Results and Provides Corporate Update Company to host quarterly conference call at 8:30am ET tomorrow

Catalyst Pharmaceuticals Announces First Quarter 2015 Financial Results and

Provides Corporate Update

Company to host quarterly conference call at 8:30am ET tomorrow

CORAL GABLES, Fla., May 11, 2015 (GLOBE NEWSWIRE) Catalyst Pharmaceutical Partners, Inc. (Nasdaq:CPRX), (Catalyst Pharmaceuticals), a

biopharmaceutical company focused on developing and commercializing innovative therapies for people with rare debilitating diseases, today reported financial results for the first quarter ended March 31, 2015.

This quarter we have been working to advance regulatory and commercial affairs and are moving closer to initiating the submission of our rolling NDA to

the FDA next quarter for Firdapse for the symptomatic treatment of LEMS said Patrick J. McEnany, Catalyst s Chief Executive Officer. This past quarter we made important

strides on our commercial infrastructure, significant progress with our pipeline, and also strengthened our cash position.

Mr. McEnany added, We recently reported that we held a productive pre-NDA meeting with the FDA and believe that our full clinical and

non-clinical data packages provide acceptable support for a complete submission of an NDA for Firdapse . We are working closely with the FDA on a pathway to include certain types of Congenital

Myasthenic Syndromes (CMS) in the initial label upon approval in LEMS and also continuing our ongoing expanded access program which provides access to Firdapse for patients with LEMS and CMS

2015 Business Achievements to Date:

Upcoming 2015 Milestones:

ended March 31, 2015, Catalyst reported a GAAP net loss of $5,410,259, or 7 cents per basic and diluted share, compared to a GAAP net loss of $3,811,119, or 7 cents per basic and diluted share, for the same period in 2014. Excluding non-cash

expense of $1,180,278 attributable to the change in fair value of liability-classified warrants, Non-GAAP1 net loss was $4,229,981 or 6 cents per basic and diluted share for the first quarter of

2015. In comparison, Non-GAAP1 net loss for the first quarter of 2014 was $3,475,605, or 6 cents per basic and diluted share, which excludes non-cash expense of $335,514 attributable to the change

in fair value of liability-classified warrants.

Research and development expenses for the first quarter of 2015 were $2,349,552 compared to $2,748,683 in

the first quarter of 2014. Research and development expenses decreased when compared to the same period in 2014 as we decreased activities related to our completed Phase 3 trial for Firdapse .

However, we expect that our research and development spend for the rest of the year will increase significantly as we prepare for and submit our NDA for Firdapse and as we increase activities

in other ongoing studies and trials.

General and administrative expenses for the first quarter of 2015 totaled $1,942,363 compared to $759,682 in the

first quarter of 2014. The increase when compared to the same period in 2014 is primarily due to an increase in pre-commercialization expenses and headcount, as we prepare for the future commercialization of Firdapse .

As a development-stage specialty pharmaceutical company, Catalyst had no revenues in either the

first quarter of 2015 or the first quarter of 2014.

At March 31, 2015, Catalyst had cash and cash equivalents, certificates of deposit and

short-term investments of $71.5 million and no debt. This includes proceeds from our February 2015 offering in which we sold 11.5 million shares of our common stock, and raised net proceeds of approximately $34.9 million. We believe that these

resources give us sufficient runway through anticipated approval and subsequent product launch of Firdapse , assuming approval in 2016.

More detailed financial information and analysis may be found in the Company s Quarterly Report on Form 10-Q, which was filed with the Securities and

Exchange Commission (SEC), May 11, 2015.

Catalyst management will host an investment-community conference call and webcast at 8:30 a.m. EDT on Tuesday, May 12, 2015 to discuss the

financial results and provide a corporate update. Investors who wish to participate in the conference call may do so by dialing (877)407-8912 for domestic and Canadian callers or (201)689-8059 for international callers. Those interested in listening

to the conference call live via the internet may do so by visiting the Investors page of the company s website at www.catalystpharma.com and clicking on the webcast link on the Investors home page. A webcast replay will be available on

the Catalyst website for 30 days following the call by visiting the Investor page of the company s website at www.catalystpharma.com.

About Catalyst Pharmaceuticals

Pharmaceuticals is a biopharmaceutical company focused on developing and commercializing innovative therapies for people with rare debilitating diseases, including Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes (CMS),

infantile spasms, and Tourette syndrome. Catalyst s lead candidate, Firdapse for the treatment of LEMS, recently completed testing in a global, multi-center, pivotal Phase 3 trial

resulting in positive top-line data. Firdapse for the treatment of LEMS has received Breakthrough Therapy Designation from the U.S. Food and Drug Administration (FDA) and orphan

drug designation for CMS. Firdapse is the first and only European approved drug for symptomatic treatment in adults with LEMS.

Catalyst is also developing CPP-115 to treat infantile spasms, epilepsy and other neurological conditions associated with reduced GABAergic signaling, like

post-traumatic stress disorder and Tourette syndrome. CPP-115 has been granted U.S. orphan drug designation for the treatment of infantile spasms by the FDA and has been granted E.U. orphan medicinal product designation for the treatment

of West Syndrome by the European Commission.

Forward-Looking Statements

This press release contains forward-looking statements. Forward-looking statements involve known and unknown risks and uncertainties, which may cause

Catalyst s actual results in future periods to differ materially from forecasted results. A number of factors, including whether the receipt of breakthrough therapy designation for Firdapse will expedite the development and review of Firdapse by the FDA or the likelihood that the product

will be found to be safe and effective, what clinical trials and studies will be required before Catalyst can submit an NDA for Firdapse for the treatment of CMS and whether any such

required clinical trials and studies will be successful, whether an NDA for Firdapse will ever be accepted for filing by the FDA, the timing of any such NDA filing

or acceptance, whether Catalyst will be the first company to receive approval for amifampridine (3,4-DAP), giving it 7-year marketing exclusivity for its product, whether CPP-115 will be determined to be safe for humans, whether CPP-115 will be

determined to be effective for the treatment of infantile spasm, post-traumatic stress disorder, Tourette Syndrome or any other indications, whether any of Catalyst s product candidates will ever be approved for commercialization or

successfully commercialized, and those other factors described in Catalyst s Annual Report on Form 10-K for the fiscal year 2014 and its other filings with the U.S. Securities and Exchange Commission (SEC), could adversely affect

Catalyst. Copies of Catalyst s filings with the SEC are available from the SEC, may be found on Catalyst s website or may be obtained upon request from Catalyst. Catalyst does not undertake any obligation to update the

information contained herein, which speaks only as of this date.

Matt Middleman, M.D.

CATALYST PHARMACEUTICAL PARTNERS, INC.

STATEMENTS OF OPERATIONS (unaudited)

CATALYST PHARMACEUTICAL PARTNERS, INC.

CONDENSED BALANCE SHEETS