3,4-Diaminopyridine in the treatment of Lambert-Eaton myasthenic syndrome. A randomized trial of 3,4-diaminopyridine in Lambert-Eaton myasthenic syndrome. 3,4-Diaminopyridine is more effective than placebo in a randomized, double-blind, cross-over drug study in LEMS. Treatment of myasthenia gravis exacerbation with intravenous immunoglobulin: a randomized double-blind clinical trial. Use of intravenous pulsed cyclophosphamide in severe, generalized myasthenia gravis. Quantitative assessment of sustained-release 4-aminopyridine for symptomatic treatment of multiple sclerosis. Randomized controlled trial of IVIg in untreated chronic inflammatory demyelinating polyradiculoneuropathy. Post-polio syndrome patients treated with intravenous immunoglobulin: a double-blinded randomized controlled pilot study. Mycophenolate mofetil as adjunctive therapy for MMN patients: a randomized, controlled trial.
Lambert-Eaton myasthenic syndrome is characterized by muscle weakness, hyporeflexia, and autonomic dysfunction, which result from impaired release of acetylcholine from cholinergic nerve terminals. It is frequently associated with cancer, it is autoimmune-mediated, and treatment has been unsatisfactory. 3,4-Diaminopyridine enhances the release of acetylcholine. In this prospective, double-blind, placebo-controlled crossover study of 12 patients with Lambert-Eaton myasthenic syndrome (7 of whom had cancer), 3,4-diaminopyridine in doses up to 100 mg per day was effective in treating both the motor and the autonomic deficits of the syndrome. Muscle strength increased from an average of 70 percent of normal to 81 percent of normal in the upper extremities, and from 45 to 65 percent of normal in the lower extremities. The amplitudes of compound-muscle-action potentials nearly doubled, increasing from an average of 2.9 mV to 5.0 mV in the arm and from 1.6 mV to 3.1 mV in the leg. Autonomic symptoms were relieved. One patient had a seizure after 10 months of treatment, but other side effects from the drug were minimal and dose-related. We conclude that 3,4-diaminopyridine, either alone or in conjunction with other therapies, may be useful in the treatment of Lambert-Eaton myasthenic syndrome. The authors report the results of a prospective, placebo-controlled, randomized study to evaluate the effectiveness of 3,4-diaminopyridine (DAP) in patients with Lambert-Eaton myasthenic syndrome (LEMS) and to determine the acute and long-term side effects of DAP.
                Twenty-six patients with LEMS completed a two-arm parallel treatment protocol in which DAP, 20 mg three times daily, or placebo was given blindly for 6 days, and a quantitative examination of muscle strength (the quantitative myasthenia gravis [QMG] score) was used as the primary measure of efficacy. After the blinded study, patients were given open-label DAP and monitored for side effects as long as there was symptomatic improvement.
                Twelve patients took DAP, and 14 took placebo. There was no difference in the age of LEMS onset, gender distribution, incidence of lung cancer, or baseline muscle strength between the patients who were randomly assigned to receive placebo and those randomly assigned to DAP. Statistical analysis using the Wilcoxon's rank sum test demonstrated that patients who received DAP had a significantly greater improvement in the QMG score and in the summated amplitude of compound muscle action potentials recorded from three sentinel limb muscles. All but one LEMS patient had significant symptomatic improvement from subsequent open-label DAP. Side effects of DAP were negligible, consisting of perioral and digital paresthesia. Laboratory measurements demonstrated no evidence of toxicity affecting liver, renal, hematologic, endocrinologic, encephalographic, or electrocardiologic function acutely or after 6 months of open-label DAP.
                This study corroborates previous studies and many years of clinical experience showing that DAP is an effective and safe treatment for LEMS. The purpose of this study was to investigate the clinical and electrophysiological efficacy of 3,4-diaminopyridine (DAP) in patients with Lambert-Eaton myasthenic syndrome (LEMS) in a randomized, double-blind, cross-over drug trial. The diagnosis of LEMS was made based on the combination of fluctuating muscle weakness, diminished or absent reflexes, and more than 60% increment of the compound muscle action potential (CMAP) amplitude after brief exercise or 50-HZ stimulation on a repetitive nerve stimulation (RNS) test. Evaluations were done at baseline, with placebo, and with 3,4-DAP (up to 75-80 mg/day). Assignment of placebo or 3,4-DAP was done in a double-blinded manner. Measurements included subjective symptoms score, objective clinical measurements [LEMS classification, muscle strength score, quantitative myasthenia gravis (QMG) score] and RNS test and single-fiber electromyography (SFEMG). The differences between placebo and baseline values (placebo change) were compared with the differences between 3,4-DAP and baseline or placebo values (DAP change). Seven patients with LEMS (QMG score >9) participated in the study. One patient had major side-effects with 3,4-DAP and withdrew from the study. Statistically significant efficacy was noted with DAP change (N = 13) compared with placebo change (N = 7) according to the subjective symptoms score (P = 0.01), LEMS classification (P < 0.001), muscle strength score (P < 0.006), QMG score (P = 0.02), and CMAP (P = 0.03). For long-term treatment, 2 patients preferred 3,4-DAP, 1 chose guanidine hydrochloride, 1 preferred pyridostigmine, and 2 chose no treatment. A randomized, double-blind, cross-over drug trial of 3,4-DAP showed significant efficacy over placebo in patients with LEMS. As a long-term treatment, however, not all patients preferred this drug. The optimal dose of intravenous immunoglobulin (IVIG) in acute exacerbation of myasthenia gravis remains unknown. Increasing the treatment duration might provide added efficacy.
                To determine the optimal dose of IVIG for treating myasthenia gravis exacerbation.
                Randomized double-blind placebo-controlled multicenter trial designed to demonstrate superiority of the 2 g/kg dose over the 1 g/kg dose of IVIG, conducted between November 13, 1996, and October 26, 2002.
                One hundred seventy-three patients aged 15 to 85 years with acute exacerbation of myasthenia gravis.
                Participants were randomly assigned to receive 1 g/kg of IVIG on day 1 and placebo on day 2 (group 1) vs 1 g/kg of IVIG on 2 consecutive days (group 2).
                Improvement in the myasthenic muscular score after 2 weeks.
                The mean improvements in the myasthenic muscular scores after 2 weeks were 15.49 points (95% confidence interval, 12.09-18.90 points) in group 1 and 19.33 points (95% confidence interval, 15.82-22.85 points) in group 2. However, the difference between the 2 groups was not significant (effect size, 3.84 [95% confidence interval, -1.03 to 8.71]; P = .12).
                This trial found no significant superiority of 2 g/kg over 1 g/kg of IVIG in the treatment of myasthenia gravis exacerbation. Twenty-three myasthenia gravis (MG) subjects, mean (SD) age 41.6 years (14), showing poor disease control or steroid-related side effects, received treatment for 12 months with intravenous cyclophosphamide (CP; n = 12) or placebo (PL; n = 11) in a randomized, double-blind trial. Pulses were given monthly at an initial dose of 500 mg/m(2) of body surface, and titrated according to changes of peripheral muscle strength or side effects. Changes of muscle strength, steroid and pyridostigmine requirements, and development of ventilatory failure or swallowing impairment were evaluated at 0, 3, 6, and 12 months. No differences were observed between groups at baseline. Statistically significant reductions of methylprednisone doses were noted in both groups but were more pronounced in subjects receiving CP than PL at 6 months (P < 0.05) and at 12 months (P < 0.03). At 12 months, five subjects on CP had tapered off their steroids whereas no subject on PL achieved further reductions (P < 0.03). Four CP subjects were not receiving steroids 36 months after completing the study and three other CP subjects had stopped pyridostigmine. CP improved muscle strength at 3 and 6 months, and this reached statistical significance compared to PL at 12 months mainly in the bulbar and masticatory (P < 0.009) and extraocular muscles (P < 0.03). Ventilatory failure was noted in one subject on CP (due to bronchopneumonia) and two on PL (due to muscle weakness). No significant increases of CP-related side effects were observed. Thus, this study suggests that intravenous pulses of CP allow reductions of systemic steroids usage without muscle strength deterioration or CP-related side effects.
                Copyright 2002 Wiley Periodicals, Inc. To evaluate the efficacy of 4-aminopyridine sustained release (4AP SR) (fampridine, EL-970) using quantitative measures of motor function in multiple sclerosis (MS) patients.
                In vitro, 4AP improves conduction through demyelinated axons. A previous multicenter trial of 4AP SR using the Expanded Disability Status Scale (EDSS) as the primary outcome was unable to establish clinical efficacy.
                Ten MS patients with stable motor deficits (EDSS 6.0-7.5) were given 4AP SR 17.5 mg bid and placebo for 1 week each in a double-blind, placebo-controlled, crossover trial. Time to walk 8 meters, time to climb four stairs, maximum voluntary isometric contraction measured quantitatively (MVICT), manual muscle testing (MMT), grip strength, EDSS, and the patient's global impression were measured.
                Timed gait was improved on 4AP SR compared with placebo in 9 of 10 subjects (p = 0.02). Timed stair climbing, MVICT, MMT, grip strength, and EDSS showed nonsignificant improvements on 4AP SR. Based on their global impressions, seven subjects preferred 4AP SR over placebo; only one preferred placebo. There were no serious side effects.
                4AP SR improved motor function in MS patients. The quantitative outcomes used in this study permit more sensitive evaluation of the therapeutic effect and promise to be useful in future trials of symptomatic treatments for MS. To determine the efficacy of IV immunoglobulin (IVIg) given patients with untreated chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).
                A randomized, double-blind, multicenter, investigator-initiated study compared IVIg (Aventis Behring LLC, King of Prussia, PA) with placebo (5% albumin). On days 1, 2, and 21, IVIg (1 g/kg) or placebo was given. The primary outcome measure was the change in muscle strength from baseline to day 42, using the average muscle score (AMS). Secondary outcome measures included change from baseline AMS at days 10 and 21, the Hughes' functional disability scale, forced vital capacity (FVC), and nerve conduction studies (NCS) of four motor nerves (median, ulnar, peroneal, and tibial).
                The patients (n = 33) were randomized. Of these, 30 (14 women, 16 men, aged 54 +/- 20 years, range 13 to 82) received IVIg and 23 were given placebo (12 women, 11 men, aged 50 +/- 18 years, range 23 to 73). Baseline AMS values of the groups were similar (IVIg 7.06 +/- 1.31 versus placebo 7.28 +/- 1.18, p = 0.53). There were two dropouts in placebo group and one in the IVIg group. Mean AMS improved at day 42 comparing IVIg with placebo (0.63 versus -0.1, p = 0.006). Improved strength was seen by day 10. The placebo group lost strength over this same interval. In the IVIg, 11 subjects improved by the functional disability scale; none worsened. This differed (p = 0.019) from those in the placebo-treated group (two improved, two got worse, remainder unchanged). Forced vital capacity did not improve with IVIg treatment. IVIg improved ulnar motor distal latency (p = 0.005), tibial distal compound muscle amplitude (p = 0.003), and peroneal nerve conduction velocity (p = 0.03).
                IVIg improves strength in patients with untreated CIDP by day 10 with continued benefit through day 42; more than one third improve by at least a functional grade on a disability scale. This study provides data supporting IVIg as the initial treatment for CIDP. Post-polio syndrome (PPS) is characterized by new muscle weakness, atrophy, fatigue and pain developing several years after the acute polio. Some studies suggest an ongoing inflammation in the spinal cord in these patients. From this perspective, intravenous immunoglobulin (IvIg) could be a therapeutic option. We performed a double-blinded randomized controlled pilot study with 20 patients to investigate the possible clinical effects of IvIg in PPS. Twenty patients were randomized to either IvIg 2 g/kg body weight or placebo. Primary endpoints were changes in pain, fatigue and muscle strength 3 months after treatment. Surrogate endpoints were changes in cerebrospinal fluid (CSF) cytokine levels. Secondary endpoints were pain, fatigue and isometric muscle strength after 6 months. Patients receiving IvIg reported a significant improvement in pain during the first 3 months, but no change was noted for subjective fatigue and muscle strength. CSF levels of tumour necrosis factor-alpha (TNF-alpha) were increased compared with patients with non-inflammatory neurological disorders. In conclusion, in this small pilot study no effect was seen with IvIg treatment on muscle strength and fatigue, however IvIg treated PPS patients reported significantly less pain 3 months after treatment. TNF-alpha was increased in the CSF from PPS patients. The results are promising, but not conclusive because of the low number of patients studied. Multifocal motor neuropathy (MMN) is an immune-mediated disorder characterized by slowly progressive asymmetrical limb weakness. Treatment with immunoglobulins (IVIg) leads to improvement of muscle strength. Anecdotal evidence suggests that immunosuppressive drugs as adjunctive therapy may be beneficial. Mycophenolate mofetil (MMF) is a potent and safe immunosuppressant. Safety and efficacy of MMF as adjunctive therapy for MMN patients receiving IVIg maintenance treatment were evaluated in a randomized controlled trial. MMN patients responding to IVIg treatment were eligible for randomization. Muscle strength and functional status were assessed at monthly intervals for 1 year. Three months after the start of MMF or placebo treatment, IVIg doses were reduced stepwise, until a deterioration of functioning or decline in muscle strength could be observed. An IVIg dose reduction of 50% during adjunctive treatment was defined as a primary endpoint. Secondary outcome measures were improvement in muscle strength and functional status after 3 months and reduction of anti GM1-IgM titres after 12 months of MMF treatment. Twenty-eight patients were randomized. One patient allocated to MMF reached the primary endpoint of 50% IVIg dose reduction. After 12 months IVIg reduction did not differ significantly between the two treatment groups. Patients did not experience drug toxicity and none of the patients showed significant disease progression after 12 months. Muscle strength and functional scores after 3 months and anti GM1-IgM titres after 12 months did not change. Adjunctive treatment of MMN patients with MMF at a dose of 1 g twice daily is safe but does not alter disease course or allow significant reduction of IVIg doses.
Limited but moderate to high quality evidence from randomised controlled trials showed that over days 3,4-diaminopyridine, or for up to 8 weeks IVIg, improved muscle strength scores and CMAP amplitudes in participants with Lambert-Eaton myasthenic syndrome. There are insufficient data at present to quantify this effect. Other possible treatments have not been tested in randomised controlled trials.