Catalyst Pharmaceuticals Announces Change to a Virtual Meeting Format for the 2020 Annual Meeting of Stockholders CORAL GABLES, Fla., August 3 , 2020 (GLOBE NEWSWIRE ) Catalyst Pharmaceuticals, Inc. (Catalyst) (Nasdaq: C

Catalyst Pharmaceuticals Announces Change to a Virtual Meeting Format for the 2020 Annual Meeting of

CORAL GABLES, Fla., August 3, 2020 (GLOBE NEWSWIRE) Catalyst Pharmaceuticals, Inc. (Catalyst)

(Nasdaq: CPRX), a commercial-stage biopharmaceutical company focused on developing and commercializing innovative therapies for people with rare debilitating, chronic neuromuscular and neurological diseases, today announced a

change in the format of its 2020 Annual Meeting of Stockholders (the Annual Meeting ) from an in-person meeting to a virtual-only meeting format. The change is being made as a result of the

coronavirus outbreak (COVID-19) and in order to protect the health and safety of Catalyst s stockholders and employees. There will be no in-person meeting. As

previously announced, the Annual Meeting will be held on Thursday, August 20, 2020 at 9:00 a.m. eastern time.

Stockholders will be able to attend

the Annual Meeting and submit questions and vote their shares during the Annual Meeting, from any location that has internet connectivity. Only stockholders of record at the close of business on June 22, 2020 ( Record Date ) will be

entitled to attend the virtual Annual Meeting. To register for the Annual Meeting, you should follow these instructions as applicable to the nature of your ownership of our common stock:

Stockholders participating in the virtual Annual Meeting will be

in a listen-only mode and will not be able to speak during the webcast. However, in order to maintain the interactive nature of the virtual meeting, virtual attendees are able to: (i) vote using the online meeting website, and (ii) submit

questions or comments to Catalyst s officers during the meeting via e-mail or the virtual meeting webcast. Starting Monday, August 17, 2020 at 9:00 AM eastern time, stockholders may submit questions

or comments before or during the meeting through the virtual meeting portal by typing in the Submit a Question box.

Stockholders will also have the option to call in to the virtual Annual Meeting by telephone and listen (in

listen-only mode) by calling:

We encourage you to access the Annual Meeting 15 minutes prior to the start time. Online

check-in will begin at 8:45 a.m. eastern time.

On or about July 6, 2020, Catalyst filed with the SEC and

mailed to its stockholders a proxy statement (the Proxy Statement ) containing information about the matters to be considered at the Annual Meeting. In connection with the matters described in this press release, Catalyst is filing with

the SEC and making available to its stockholders a supplement to its Proxy Statement ( Supplement ), containing additional information about the matters to be considered at the Annual Meeting. Catalyst s Proxy Statement, its

Supplement, and its annual report for the year ended December 31, 2019, are available for download on Catalyst s website at https://ir.catalystpharma.com/financial-information/annual-reports and on Continental s website at

https://www.cstproxy.com/catalystpharma/2020.

About Catalyst Pharmaceuticals

Catalyst Pharmaceuticals is a commercial-stage biopharmaceutical company focused on developing and commercializing innovative therapies for people with rare

debilitating, chronic neuromuscular and neurological diseases, including Lambert-Eaton myasthenic syndrome (LEMS), anti-MuSK antibody positive myasthenia gravis (MuSK-MG) and spinal muscular atrophy (SMA) Type 3. Catalyst s new drug application

for Firdapse (amifampridine) 10 mg tablets for the treatment of adults with LEMS was approved in November 2018 by the U.S. Food & Drug Administration ( FDA ), and

Firdapse is now commercially available in the United States. Prior to its approval, Firdapse for LEMS had received breakthrough therapy designation and orphan drug designation from the FDA.

Firdapse is currently being evaluated in clinical trials for the treatment of MuSK-MG and SMA Type 3 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 those factors described in Catalyst s Annual Report on Form 10-K for the

fiscal year 2019 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.