A new drug called 3,4-Diaminopyridine (3,4-DAP) is currently under investigation for
treatment of the symptoms of Lambert-Eaton Myasthenic Syndrome (LEMS). This is an expanded
access trial, which means that although data from this study will be collected and reported
to the US Food and Drug Administration (FDA)and the drug manufacturer, this is not a formal
study of drug in LEMS.
If you decide volunteer, you will be evaluated by a neurologist to determine your
eligibility to receive 3, 4-DAP by a review of your medical history, medication regimen (the
medications you are taking) and a neurological examination. If you are a female of
child-bearing potential, a serum pregnancy test will be done to ensure that you are not
pregnant. Once it is determined that this treatment is appropriate for your care, you will
begin taking 3, 4 DAP by mouth in slowly increasing doses. Treatment will begin with 5mg
three times a day, as clinically needed, and if tolerated. You will be monitored for
strength and side effects by routine clinic visits at initial intervals of once a month,
increasing to intervals of every 6 months as permitted. Blood will be drawn (approximately 1
tablespoon) at every clinic visit or as often as the investigator deems necessary to assess
your liver/kidney function and blood counts. You will have an EKG (a test to see how your
heart is functioning) at your first study visit, after 6 months of taking 3,4 DAP and again
every 2 years. Treatment will be continued indefinitely if a good clinical response is
achieved. This study is planned to last indefinitely.
The dosage of 3, 4DAP is individually adjusted. The usual range is 10-15 mg 3-4 times per
day for the full effect and will increase by 50% every two weeks to 10-15 mg three to six
times a day, as needed and if tolerated. Dosages above the full effect level will not
provide an additional benefit and should not be used. 3, 4 DAP is a convulsant (causes
seizures). A total of 100 mg/day is the maximum dosage allowed.
Patients with clinically-confirmed LEMS will receive 3, 4-DAP by mouth in slowly increasing
doses. Treatment will begin with 5 mg, three times a day and will increase by 50% every two
weeks to 10-15 mg, three to six times a day, as clinically needed, and if tolerated.
Patients will be monitored for strength and side effects via routine out-patient clinic
visits at initial intervals of 1 month, increasing to intervals of 6 months as permitted.
Results of treatment and adverse events will be reported to the FDA. Treatment will be
continued indefinitely if a good clinical response is achieved and side effects are
- Be 18 years or older, diagnosed with LEMS
- If female, have negative pregnancy test and if premenopausal, be willing to practice
an effective form of birth control during the study.
- Is known to have a sensitivity to 3, 4 DAP
- Has a history of past or current seizures
- Has a history of past or current severe asthma
- Is believed by the investigator to be unable to comply with the protocol
- Unable to give informed consent