Jacobus Begins Invitation-Only Trial of 3,4-DAP in LEMS

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Jacobus Pharmaceutical of Princeton, N.J., has opened a randomized, placebo-controlled study of the drug 3,4-diaminopyridine (3,4-DAP) in 30 adults with Lambert-Eaton myasthenic syndrome (LEMS) who have been receiving the drug through its expanded access program. Enrollment is by invitation only.

The study is being conducted to confirm the safety and test the efficacy of 3,4-DAP in the treatment of LEMS-related weakness.

LEMS is caused by a misdirected attack of the immune system on nerve endings at the neuromuscular junction, the place where nerve and muscle fibers connect. The disorder causes muscle weakness and sometimes other symptoms, such as dry mouth or constipation.

In the United States, the disease is treated with medications that suppress the immune system and/or medications that slow the breakdown of acetylcholine (cholinesterase inhibitors).

3,4-DAP increases acetylcholine release

3,4-DAP increases the release of acetylcholine, a chemical transmitter of signals from the nervous system that activates muscle fibers.

In this phase 2 trial, participants will be randomly assigned to continue their usual dosage of 3,4-DAP or to gradually reduce (taper) their 3,4-DAP down to zero (a placebo). Neither the investigators nor the participants will know who is taking their usual dose and who is in the "taper to placebo" group until the trial has been completed.

Participants will take "timed up and go" functional tests, which measure how long it takes for someone to move from a sitting to a standing position and then walk a short distance; they also will report their own assessment of LEMS-related weakness.

Jacobus trial participants must meet study criteria

Invited participants must:

• be invited to enroll by the study investigators;
• be at least 18 years old;
• have a confirmed LEMS diagnosis;
• have been taking Jacobus-produced 3,4-DAP continuously for at least three months; and
• meet other study criteria.

Study sites are in Rochester, Minn.; Durham, N.C., Portland, Ore.; and Salt Lake City.

For details, see Effectiveness of 3,4-Diaminpyridine in Lambert-Eaton Myasthenic Syndrome (DAPPER); or go to ClinicalTrials.gov and enter NCT01511978 in the search box.

To participate in other 3,4-DAP studies and programs

Access to 3,4-DAP for treatment of LEMS is available via an expanded access program in several U.S. cities. Go to ClinicalTrials.gov, and enter 3,4-diaminopyridine in the search box.

The pharmaceutical company BioMarin is conducting a study of its 3,4-DAP drug, known as Firdapse. For more about this trial, see A Phase 3 Study of Amifampridine Phosphate in Patients With Lambert-Eaton Myasthenic Syndrome, or enter NCT01377922 into the search box at ClinicalTrials.gov.

Also see BioMarin Seeking US Approval of LEMS Drug, Quest News Online, Nov. 18, 2011.

About Clinical Trials A clinical trial is a test, in humans, of an experimental treatment. Although it's possible that benefit may be derived from participating in a clinical trial, it's also possible that no benefit, or even harm, may occur. MDA has no ability to influence who is chosen to participate in a clinical trial. To learn more, see Understanding Clinical Trials and Being a Co-Adventurer, which is about neuromuscular disease clinical trials. To see a continuously updated database of clinical trials, go to ClinicalTrials.gov.