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

Catalyst Pharmaceuticals Announces Second Quarter 2015 Financial Results and

Provides Corporate Update

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

CORAL GABLES, Fla., Aug 10, 2015 (GLOBE NEWSWIRE) Catalyst Pharmaceuticals, Inc. (Nasdaq:CPRX), a biopharmaceutical company focused on

developing and commercializing innovative therapies for people with rare debilitating diseases, today reported financial results for the second quarter and six months ended June 30, 2015.

This quarter we have been working diligently to advance regulatory and commercial affairs and are pleased with the initiation of our rolling NDA

submission to the FDA for Firdapse for the symptomatic treatment of Lambert-Eaton myasthenic syndrome (LEMS) said Patrick J. McEnany, Catalyst s Chief Executive Officer.

We expect to complete our submission during Q4, putting us on schedule for a potential approval by the middle of 2016. We are working on a pathway to include certain types of congenital myasthenic syndromes (CMS) in the initial label, in

addition to LEMS. Additionally, we are on schedule with our key commercial strategic imperatives to support the successful launch of Firdapse .

Mr. McEnany added, We recently reported top-line results in our proof-of-concept trial of vigabatrin in patients with treatment-refractory

Tourette s Disorder and are hoping to move forward using CPP-115 as a candidate for future trials.

Q2 and Recent Highlights:

Upcoming 2015 Milestones:

For the quarter ended June 30, 2015, Catalyst reported a GAAP net loss of $4,558,503, or 6 cents per basic and diluted share, compared to a GAAP net loss

of $3,198,020, or 5 cents per basic and diluted share, for the same period in 2014. Excluding non-cash gain of $333,956 attributable to the change in fair value of liability-classified warrants,

Non-GAAP1 net loss was $4,892,459 or 6 cents per basic and diluted share for the second quarter of 2015. In comparison, Non-GAAP1 net loss

for the second quarter of 2014 was $2,974,429, or 5 cents per basic and diluted share, which excludes non-cash expense of $223,591 attributable to the change in fair value of liability-classified warrants.

For the six months ended June 30, 2015, Catalyst reported a GAAP net loss of $9,968,762, or 13 cents per basic and diluted share, compared to a GAAP net

loss of $7,009,139, or 12 cents per basic and diluted share, for the same period in 2014. Excluding non-cash expense of $846,322 attributable to the change in fair value of liability-classified warrants, Non-GAAP1 net loss was $9,122,440 or 12 cents per basic and diluted share for the first six months of 2015. In comparison, Non-GAAP1 net loss for the first

six months of 2014 was $6,450,034, or 11 cents per basic and diluted share, which excludes non-cash expense of $559,105 attributable to the change in fair value of liability-classified warrants.

Research and development expenses for the second quarter of 2015 were $2,577,508 compared to $2,098,958 in the second quarter of 2014. For the six months

ended June 30, 2015 research and development expenses were $4,927,060 compared to $4,847,641 in the same period in 2014. Research and development expenses increased when compared to the same period in 2014 as we increased activities related to

our NDA filing for Firdapse and ongoing studies and trials and decreased activities related to our completed Phase 3 trial for

Firdapse . We expect that our research and development spend for the rest of the year will increase 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 second quarter of 2015 totaled $2,319,822 compared to $891,215 in the second quarter of 2014. For the six months ended June 30, 2015 general and administrative expenses were $4,262,185 as compared to $1,650,897 in the same

period in 2014.The increase when compared to the same period in 2014 is primarily due to increases in pre-commercialization expenses and headcount, in preparation for the future commercialization of Firdapse .

As a development-stage biopharmaceutical company, Catalyst had no revenues in the second quarter

of 2015 and 2014 or the first six months of 2015 and 2014.

At June 30, 2015, Catalyst had cash and cash equivalents, certificates of deposit and short-term investments

of $67.4 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) on August 10, 2015.

Catalyst management will host an investment-community conference call and webcast at 8:30 a.m. EDT on Tuesday, August 11, 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 atwww.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 s Disorder. 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 designations for LEMS and 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 s Disorder. 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, if an NDA for Firdapse is accepted for filing, such NDA will be given a priority review by the FDA, 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 s Disorder 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.

CATALYST PHARMACEUTICALS, INC.

STATEMENTS OF OPERATIONS (unaudited)

CATALYST PHARMACEUTICALS, INC.

CONDENSED BALANCE SHEETS