Catalyst Pharmaceuticals Announces First Quarter 2020 Financial Results and Provides Corporate Update -Firdapse Q1 2020 Net Revenues of $29.1 Million -First Quarter 2020 GAAP Net Income of $10.4 Million -Catalyst Withdra

Catalyst Pharmaceuticals Announces First Quarter 2020 Financial Results and Provides Corporate Update

-Firdapse Q1 2020 Net Revenues of $29.1 Million

-First Quarter 2020 GAAP Net Income of $10.4 Million

-Catalyst Withdraws Previous 2020 Revenue Guidance Due to COVID-19 Uncertainties

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

CORAL GABLES, Fla., May 11, 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 reported financial results for the first quarter ended March 31,

2020 and provided a corporate update.

I am very proud of the way that the entire Catalyst team has quickly responded and adapted in these

challenging and unprecedented times to ensure the safety of all employees, while still providing uninterrupted access to Firdapse for LEMS patients and continuing our support with their

healthcare providers, albeit remotely said Patrick J. McEnany, Chairman and Chief Executive Officer of Catalyst Pharmaceuticals. We entered 2020 with a very clear operational plan to drive the growth of the Firdapse franchise, advance

our clinical development programs, including MuSK antibody positive Myasthenia Gravis, and secure our supply chain and safety stock of Firdapse. We have made progress against all of these objectives and our first quarter results reflect the solid

execution of this plan.

Q1-20 Financial Results

Recent Developments and Highlights

Financial Highlights and Guidance

ended March 31, 2020, Catalyst reported net income of $10.4 million, or $0.10 per basic and diluted share, compared to a net loss of $645 thousand, or $0.01 per basic and diluted share, for the same period in 2019. Excluding expenses

related to stock-based compensation of $1.5 million, non-GAAP1 net income for the first quarter of 2020 was $11.9 million, or $0.12 per basic

share and $0.11 per diluted share. This compares to a non-GAAP1 net income of $289 thousand, or $0.00 per basic and diluted share, excluding

stock-based compensation expense of $933 thousand, for the first quarter of 2019.

Catalyst launched its first product, Firdapse, in January 2019. Related product revenues, net for the

quarter ended March 31, 2020 were $29.1 million compared to $12.4 million in the same period of 2019. Cost of sales for the quarter ended March 31, 2020 were $4.2 million compared to $1.7 million in the same period in

Research and development expenses for the first quarter of 2020 were $4.2 million, compared to $3.3 million in the first quarter of 2019.

The increase of $915 thousand in research and development expenses for the first three months of 2020 is primarily attributable to increases in headcount, medical and regulatory affairs, quality assurance programs, and expenses from our

Firdapse clinical trials and studies, as well as an increase in non-cash employee-stock based compensation. The Company expects that costs related to research and development activities will continue to be

substantial throughout 2020 as Catalyst continues its clinical programs evaluating Firdapse in MuSK-MG and SMA Type 3, continues its Expanded Access Program and sustained release product development program

for Firdapse, begins to evaluate Firdapse as a treatment for other neuromuscular diseases and, assuming positive results from the trial, prepares a sNDA for Firdapse for the treatment of MuSK-MG.

Selling, general and administrative expenses for the first quarter of 2020 totaled $10.1 million as compared to $8.4 million in the first quarter of

2019. The increase when compared to the same period in 2019 is primarily due to additional cost from expansion of the sales force and contracting with a rare-disease experienced inside sales agency, and an increase in

non-cash stock-based compensation. The Company expects selling, general and administrative expenses to increase in 2020, as the Company continues to build its infrastructure and commercial and patient programs

in support of Firdapse sales activities.

At March 31, 2020, Catalyst had cash and cash equivalents and investments of $101.8 million and no

funded-debt. Catalyst believes that its existing capital resources will be sufficient to support its planned operations for at least the next 12 months.

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 May 11, 2020.

Catalyst management will host an investment-community conference call and webcast at 8:30 a.m. ET, tomorrow, Tuesday, May 12, 2020 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 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 as a treatment for adults (age 17 and up) with LEMS. 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

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 impact of the effects of the COVID-19 pandemic on Catalyst s 2020 net product revenues and on the timeline for reporting the top-line results

from Catalyst s MuSK-MG trial and SMA Type 3 proof-of-concept study, and (ii) 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.

CATALYST PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited)

CATALYST PHARMACEUTICALS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS