Catalyst Pharmaceuticals Announces Abstract on Lambert Eaton Myasthenic Syndrome (LEMS) to be Presented at the Upcoming IASLC 2023 World Conference of Lung Cancer

Study Reveals LEMS Often Goes Undiagnosed in U.S. Patients with Small Cell Lung Cancer

CORAL GABLES, Fla., Aug. 16, 2023 (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 announced that an abstract assessing the prevalence of Lambert-Eaton myasthenic syndrome (“LEMS”) among patients with small cell lung cancer (“SCLC”) in the United States, was accepted and will be presented at the IASLC 2023 World Conference of Lung Cancer (#WCLC23) hosted by the International Association for the Study of Lung Cancer, happening September 9-12, 2023 in Singapore.

The abstract details the results from a study analyzing real-world data to determine the prevalence of LEMS diagnoses among patients with SCLC in the United States. While published data estimate that 3% of patients with SCLC have a concurrent LEMS diagnosis, this analysis of oncology healthcare claims between 2017-2022 found that 0.16 – 0.24% of patients with SCLC had LEMS claims, indicating a 10-fold underdiagnosis of LEMS in patients with SCLC. The authors hypothesize non-specific LEMS symptoms, such as fatigue and weakness, may have been attributed to SCLC, leading to underdiagnosis. These data imply that the overall population of LEMS is significantly larger than previous estimates.

Presentation Details:
Poster Session: P2.31 - Global Health, Health Services, and Health Economics – Real World Data
Title: Lambert-Eaton Myasthenic Syndrome is Underrecognized in Small Cell Lung Cancer: An Analysis of Real-World Data
Date Monday, September 11, 2023
Time: 6:00 PM -7:30 PM Singapore Time (SST) / 6:00 AM – 7:30 AM U.S. Eastern Time (ET)
Presenter: David Morrell, MBA, SVP Marketing at Catalyst Pharmaceuticals

“The results from the study have brought to light significant insights into the relationship between small-cell lung cancer and Lambert Eaton myasthenic syndrome, or LEMS. This research adds to the growing body of evidence illustrating that the prevalence of LEMS, including individuals with small cell lung cancer, is now estimated to be about 3,600 to 5,400 people (1-6) in the United States, of which a substantial number currently remain undiagnosed and untreated,” stated Patrick J. McEnany, Chairman and CEO of Catalyst. “Our hope is that this study will contribute to heightened awareness, leading to early diagnoses and ultimately improving the quality of life for those affected by LEMS and small cell lung cancer.”

Learn more about #WCLC23 here:

About Catalyst Pharmaceuticals

With exceptional patient focus, Catalyst is committed to developing and commercializing innovative first-in-class medicines that address rare neurological and epileptic diseases. Catalyst’s flagship U.S. commercial product is FIRDAPSE® (amifampridine) Tablets 10 mg, approved for the treatment of Lambert-Eaton myasthenic syndrome ("LEMS") for adults and for children ages six to seventeen. In January 2023, Catalyst acquired the U.S. commercial rights to FYCOMPA® (perampanel) CIII, a prescription medicine approved in people with epilepsy aged four and older alone or with other medicines to treat partial-onset seizures with or without secondarily generalized seizures and with other medicines to treat primary generalized tonic-clonic seizures for people with epilepsy aged 12 and older. Further, Canada’s national healthcare regulatory agency, Health Canada, has approved the use of FIRDAPSE for the treatment of adult patients in Canada with LEMS. Further, on July 18, 2023, Catalyst acquired an exclusive license for North America for vamorolone, a promising best-in-class dissociative anti-inflammatory steroid treatment for Duchenne Muscular Dystrophy. Vamorolone has received FDA Orphan Drug and Fast Track designations and has been granted a PDUFA action date of October 26, 2023.

For more information about Catalyst Pharmaceuticals, Inc., visit the Company’s website at: For the Full Prescribing and Safety Information for FIRDAPSE®, please visit For the Full Prescribing Information for FYCOMPA®, please visit


  1. American Cancer Society. Key Statistics for Lung Cancer. 2023.
  2. Rudin CM, Brambilla E, Faivre-Finn C, Sage J. Nat Rev Dis Primers 2021; 7(1):
  3. Titulaer MJ, Maddison P, Sont JK, et al. J Clin Oncol 2011; 29: 902–08.
  4. Wirtz PW, Lang B, Graus F, et al. J Neuroimmunol 2005; 164(1-2): 161-5.
  5. Gozzard P, Woodhall M, Chapman C, et al. Neurology 2015; 85(3): 235-9.
  6. Payne M, Bradbury P, Lang B, et al. J Thorac Oncol 2010; 5(1): 34-8.

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 2022 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.

Source: Catalyst Pharmaceuticals, Inc.


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