News & Events

Your online link to LEMS-related developments

Find the latest information about Lambert-Eaton myasthenic syndrome (LEMS), FIRDAPSE, and other related topics and events.

Increased Maximum Daily Dose for Firdapse is FDA Approved
FIRDAPSE Gains Pediatric Approval
COVID-19 and LEMS Patients


On May 30, 2024, Catalyst Pharmaceuticals, Inc. received approval by the U.S. Food and Drug Administration (FDA) increasing the indicated maximum daily dose of FIRDAPSE (amifampridine) for adults from 80 mg to 100 mg for the treatment of Lambert-Eaton myasthenic syndrome (“LEMS”). The maximum daily dose was also increased for pediatric patients weighing more than 45 kg from 40 mg to 50 mg. This increased maximum daily dose offers healthcare providers and patients greater flexibility in treatment regimens for the management of LEMS.

“We are pleased to receive the approval for the increased maximum daily dose of FIRDAPSE,” stated Richard J. Daly, President and CEO of Catalyst. “This pivotal achievement further underscores our dedication to meeting the evolving needs of LEMS patients and their healthcare providers. We believe that this milestone will have a meaningful impact on the lives of LEMS patients, offering a new level of flexibility in treatment while aligning with our overarching mission to optimize LEMS patient outcomes.”

Patients in the U.S. can access FIRDAPSE by prescription through their healthcare providers. For those seeking more information, the Catalyst Pathways® Patient Assistance Program for FIRDAPSE offers comprehensive support, included a dedicated team to assist families throughout the treatment journey for eligible patients. Caregivers and healthcare professional may call 1-833-422-8259 or visit for further details.


On September 29, 2022, Catalyst Pharmaceuticals, Inc., received FDA approval to expand the indicated age range for FIRDAPSE (amifampridine) Tablets 10 mg to include pediatric patients 6 years of age and older for the treatment of Lambert-Eaton myasthenic syndrome (“LEMS”). FIRDAPSE is currently approved in the US and Canada for the treatment of LEMS in adult patients.

“We are very pleased to have received FDA approval for the expanded pediatric indication for FIRDAPSE. While the US LEMS pediatric population is an exceptionally small number of patients, this positive outcome helps ensure that all eligible LEMS patients have access to FIRDAPSE for the treatment of this rare disease,” stated Patrick J. McEnany, Chairman and CEO of Catalyst.

“This milestone represents our long-standing and unwavering commitment to the LEMS patient community, and we are pleased that this medicine is now available for this important patient population. We look forward to building upon our recent achievements with a sustained focus on addressing the needs of LEMS patients. We thank the Agency for their collaboration during the review of this application and our Catalyst employees for their shared commitment to improving the lives of patients.”

As part of Catalyst’s efforts to help ensure those patients who can benefit from FIRDAPSE are able to obtain access, Catalyst offers a comprehensive patient access support program and patient assistance for qualifying LEMS patients through its Catalyst Pathways® program. More information is available for prescribers and patients by visiting or by calling 1-833-422-8259.


In 2020, the COVID-19 Working Group—an international coalition of physicians and scientists—released treatment guidelines for patients with LEMS and related neuromuscular conditions during the coronavirus pandemic.37 Since that article was published, the situation has evolved significantly.

The American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) continues to review currently available resources and recommendations from the most reputable sources of healthcare information to guide physicians who treat patients with neuromuscular disorders.

Visit the AANEM website for the latest guidance regarding COVID-19