Catalyst Pharmaceuticals Announces Second Quarter 2016 Financial Results and Provides Product Development Update Company to Host Quarterly Conference Call at 8:30 am ET Tomorrow

Catalyst Pharmaceuticals Announces Second Quarter 2016 Financial Results and

Provides Product Development Update

Company to Host Quarterly Conference Call at 8:30 am ET Tomorrow

CORAL GABLES, Fla., August 9, 2016 (GLOBE NEWSWIRE) Catalyst Pharmaceuticals, Inc. (Catalyst) (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, 2016 and provided a product development update.

We were pleased to have reached agreement with the FDA during the quarter on the clinical trial protocol for our second pivotal Phase 3 trial for

Firdapse in the treatment of Lambert-Eaton Myasthenic Syndrome (LEMS) , said Patrick J. McEnany, Chief Executive Officer of Catalyst. We expect to initiate a small, efficient short

term study with Firdapse during the second half of 2016, as we continue to expend additional research dollars studying other potential neuromuscular indications for Firdapse. As stated previously, we believe that our existing capital resources are

adequate to get us to an accepted NDA submission without the need for additional financing.

Q2 and Recent Highlights

PRODUCT DEVELOPMENT UPDATE

NDA resubmission plan

for Congenital Myasthenic Syndromes (CMS)

for MuSK antibody positive Myasthenia Gravis

CPP-115 (next generation GABA-AT inhibitor)

Generic Sabril (generic ingredient vigabatrin)

For the quarter ended June 30, 2016,

Catalyst reported a GAAP net loss of $4,568,914 or 6 cents per basic and diluted share, as compared to a GAAP net loss of $4,558,503 or 6 cents per basic and diluted share, for the same period in 2015. Excluding non-cash gain of $152,783

attributable to the change in fair value of liability-classified warrants, Non-GAAP1 net loss was $4,721,697 or 6 cents per basic and diluted share for the second quarter of 2016. In comparison,

Non-GAAP1 net loss for the second quarter of 2015 was $4,892,459 or 6 cents per basic and diluted share, which excludes non-cash gain of $333,956 attributable to the change in fair value of

liability-classified warrants.

For the six months ended June 30, 2016, Catalyst reported a GAAP net loss of $9,955,151, or 12 cents per basic

and diluted share, as compared to a GAAP net loss of $9,968,762, or 13 cents per basic and diluted share, for the same period in 2015. Excluding non-cash gain of $886,139 attributable to the change in fair value of liability-classified warrants,

Non-GAAP1 net loss was $10,841,290 or 13 cents per basic and diluted share for the first six months of 2016. In comparison, Non-GAAP1 net loss

for the first six months of 2015 was $9,122,440, or 12 cents per basic and diluted share, which excludes non-cash expense of $846,322 attributable to the change in fair value of liability-classified warrants.

Research and development expenses for the second quarter of 2016 were $2,508,897 as compared to $2,577,508 in the second quarter of 2015. For the six months

ended June 30, 2016, research and development expenses were $6,055,288 as compared to $4,927,060 in the same period in 2015. Research and development expenses for the first six months of 2016 increased when compared to the same period in 2015, due

primarily to consulting fees relating to regulatory matters, activities related to the Firdapse expanded access program, including manufacturing of related drug, and increased activities in ongoing studies and trials. We expect that costs related to

research and development activities will continue to be substantial throughout the balance of 2016 and into 2017.

General and administrative expenses for

the second quarter of 2016 totaled $2,305,555 as compared to $2,319,822 in the second quarter of 2015. For the six months ended June 30, 2016, general and administrative expenses were $4,996,700 as compared to $4,262,185 in the same period in 2015.

The increase when compared to the same period in 2015 is primarily due to increases in pre-commercialization expenses, payroll and benefits expenses during the first half of 2016, including approximately $600,000 for severance costs related to the

reduction in force that occurred in May 2016, partly offset by our initiatives to conserve resources. We expect general and administrative expenses to decrease during the remainder of 2016 as we continue taking steps to conserve our available

As a development-stage biopharmaceutical company, Catalyst had no revenues in the second quarter of 2016 and 2015 or the first six months of

At June 30, 2016, Catalyst had cash and cash equivalents, certificates of deposit and short-term investments of $48.0 million and no debt.

Catalyst believes that these resources give it sufficient runway for at least the next year. However, until Catalyst finalizes the details and logistics of its required confirmatory study evaluating Firdapse for the treatment of LEMS, it will be

difficult for Catalyst to provide more details regarding how far its existing resources will take it. Notwithstanding, and while there can be no assurance, Catalyst continues to believe that its currently available resources will be sufficient to

complete the development of Firdapse and get to an accepted NDA submission for Firdapse without the need for additional financing.

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), August 9th, 2016

Catalyst management will host an

investment-community conference call and webcast at 8:30 a.m. ET on Wednesday, August 10, 2016 to discuss the financial results and provide a product development 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

Catalyst 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. 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 LEMS and CMS. Firdapse is the first and only approved drug in Europe 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. In addition, Catalyst is developing a generic version of Sabril (vigabatrin).

Forward-Looking Statements

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 study design for a second trial evaluation Firdapse for the treatment of LEMS will be acceptable to the FDA, the timing of such trial, and whether it will be successful, whether Catalyst s assumptions

in its updated business plan will be accurate and the impact of unanticipated events or delays in projected activities on Catalyst s cash requirements and on Catalyst s ability to get to an accepted NDA submission for Firdapse without the

need for additional funding, what clinical trials and studies will be required before Catalyst can resubmit an NDA for Firdapse for the treatment of CMS and whether any such required clinical trials and studies will be successful, whether the

investigator-sponsored study evaluating Firdapse for the treatment of MuSK-MG will be successful, whether any NDA for Firdapse resubmitted to the FDA will ever be accepted for filing, 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 Firdapse will ever be approved for commercialization, 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, what additional testing will be required before CPP-115 is Phase 2 ready , whether CPP-115 will be determined to

be effective for the treatment of infantile spasms, post-traumatic stress disorder, Tourette s Disorder or any other indications, whether Catalyst can successfully design and complete a bioequivalence study of its version of vigabatrin compared

to Sabril that is acceptable to the FDA, whether any such bioequivalence study the design of which is acceptable to the FDA will be successful, whether any ANDA that Catalyst submits for a generic version of Sabril will be accepted

for filing, whether any ANDA for Sabril accepted for filing by the FDA will be approved (and the timing of any such approval), 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 2015 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.

PHARMACEUTICALS, INC.

STATEMENTS OF OPERATIONS (unaudited)

CATALYST PHARMACEUTICALS, INC.

CONDENSED BALANCE SHEETS