Exhibit 99.1

Catalyst Pharmaceuticals Announces Second Quarter 2021 Financial Results and Provides Corporate Update

-Q2 2021 Total Net Revenues of $36.4 Million Reflect Strong Quarter over Quarter Growth

-Q2 2021 GAAP Net Income of $12.2 Million; Non-GAAP Net Income of $17.4 Million

-$155.3 Million in Cash and Investments and no Funded Debt at End of Q2-2021

-Catalyst to Host Quarterly Conference Call at 8:30 AM ET Tomorrow

CORAL GABLES, Fla., August 9, 2021 (GLOBE NEWSWIRE) — Catalyst Pharmaceuticals, Inc. (Catalyst) (Nasdaq:CPRX), a commercial-stage, patient-centric biopharmaceutical company focused on in-licensing, developing and commercializing novel high-quality medicines for patients living with rare diseases, today reported financial results for the second quarter ended June 30, 2021 and provided a corporate update.

“I am very pleased that our operational plan for 2021 and year to date financial results continue to deliver as originally planned, despite not yet being back to pre-Covid conditions. I believe that this portends well for the balance of the year, as we anticipate that patient access to physician practices will continue to improve. This should lead to abbreviated diagnostic times for new Lambert-Eaton Myasthenic Syndrome (LEMS) patients, which will mean that these patients will have access to Firdapse® much sooner,” said Patrick J. McEnany, Chairman and Chief Executive Officer of Catalyst Pharmaceuticals. “Additionally, in line with our strategic objectives we have recently expanded our senior leadership team with highly regarded pharmaceutical executives to help us accelerate our business and portfolio development activities and continue the transformation of the company.”

Q2-21 Financial Results

Corporate Milestones

Balance Sheet and Key Activities in 2021

The Company plans to continue investing in the following key activities in 2021:

More detailed financial information and analysis can be found in the Company’s Quarterly Report on Form 10-Q, which was filed with the Securities and Exchange Commission (SEC) on August 9, 2021.

Non-GAAP Financial Measures

Non-GAAP¹ net income for Q2-21 was $17.4 million ($0.17 per basic and $0.16 per diluted share), which excludes from GAAP net income of $12.2 million (i) stock-based compensation expense of $1.5 million, (ii) depreciation of $31 thousand, and (iii) the provision for income taxes of $3.7 million. This compares to non-GAAP¹ net income for Q2-20 of $12.2 million ($0.12 per basic and $0.11 per diluted share), which excludes from GAAP net income of $9.8 million (i) stock-based compensation expense of $1.8 million, (ii) depreciation of $29 thousand, and (iii) the provision for income taxes of $0.6 million. A tabular presentation of non-GAAP¹ net income for the three months and six months ended June 30, 2021 and 2020 is included on page 5 of this press release.

The non-GAAP financial measures in this press release exclude from the calculation of net income (i) the expense associated with non-cash stock-based compensation, (ii) depreciation expense, and (iii) the provision for income taxes. Non-GAAP income per share is calculated by dividing non-GAAP income by the weighted average common shares outstanding.

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Conference Call

Catalyst management will host an investment-community conference call and webcast at 8:30 a.m. ET, tomorrow, Tuesday, August 10, 2021 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

Catalyst Pharmaceuticals is a commercial-stage, patient-centric biopharmaceutical company focused on in-licensing, developing and commercializing novel high-quality medicines for patients living with rare diseases. With exceptional patient focus, Catalyst is committed to developing a robust pipeline of cutting-edge, first- or best-in-class medicines for rare diseases. Catalyst’s New Drug Application for Firdapse® (amifampridine) Tablets 10 mg for the treatment of adults with LEMS was approved in 2018 by the U.S. Food & Drug Administration (“FDA”), and Firdapse® is commercially available in the United States as a treatment for adults with LEMS. Further, Canada’s national healthcare regulatory agency, Health Canada, approved the use of Firdapse® (amifampridine) for the treatment of adult patients in Canada with LEMS.

Firdapse® is currently being evaluated in clinical trials for the treatment of MuSK-MG and has received Orphan Drug Designation from the FDA for myasthenia gravis.

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 (i) the continuing effect of the COVID-19 pandemic on Catalyst’s net product revenues and net income, (ii) Catalyst’s ability to locate and acquire new product candidates through acquisition or in-licensing, (iii) Catalyst’s ability to successfully develop any new product candidates acquired or in-licensed, (iv) Catalyst’s ability to successfully develop Firdapse® for other indications and to successfully develop and commercialize a long acting formulation of Firdapse®, and (v) those factors described in Catalyst’s Annual Report on Form 10-K for fiscal year 2020 and Catalyst’s 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.

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CATALYST PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited)

(in thousands, except share data)

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CATALYST PHARMACEUTICALS, INC.

RECONCILIATION OF NON-GAAP METRICS (unaudited)

(in thousands, except share data)

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CATALYST PHARMACEUTICALS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands)

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