Conference Coverage
Biologics
Several biologics are being studied as treatments for various neuromuscular disorders. In a phase III study in patients with refractory generalized myasthenia gravis, eculizumab, which inhibits complements and the membrane attack complex, did not result in a significant improvement in Myasthenia Gravis–Activities of Daily Living Profile score. Eculizumab did, however, significantly improve a secondary end point, Quantitative Myasthenia Gravis total score.
A phase II trial to evaluate rituximab in myasthenia gravis has completed enrollment. Results may be available in approximately a year. Rituximab also is being studied in juvenile and adult dermatomyositis and chronic inflammatory demyelinating polyneuropathy (CIDP), Dr. Peltier said.
Etanercept and infliximab, treatments for rheumatoid arthritis that act on tumor necrosis factor alpha, are being studied in dermatomyositis and polymyositis. Tocilizumab, a treatment for rheumatoid arthritis that inhibits IL-6 receptors, is being studied in those disorders as well.
Alemtuzumab has been shown to stabilize quantitative muscle testing in sporadic inclusion body myositis and may be helpful in refractory CIDP, Dr. Peltier said.
Myasthenia Gravis
Researchers in August published the results of a randomized trial that found that thymectomy improves clinical outcomes over three years in patients with nonthymomatous myasthenia gravis. Patients who underwent thymectomy and received alternate-day prednisone had a lower time-weighted average Quantitative Myasthenia Gravis score, compared with patients who received alternate-day prednisone alone. Thymectomy had been a mainstay in the treatment of myasthenia gravis, although prior nonrandomized studies had not provided conclusive evidence of its benefit. “The MGTX trial was based on the traditional method of thymectomy requiring sternotomy,” she said. “Further trials comparing the effectiveness of full sternotomy versus newer methods utilizing transcervical approaches or partial sternotomy will most likely be coming.”
A trial of subcutaneous IV immunoglobulin (IVIg) in myasthenia gravis is enrolling patients. Additional data to support the use of IVIg in myasthenia gravis would improve patient outcomes due to the ease of delivering IVIg versus plasma exchange, Dr. Peltier said.
Neuropathy
Investigators have pooled data for patients with neuropathy who have received IVIg. The INSIGHTS Quality Improvement Registry includes data from 585 patients. Researchers have found that patients who fulfill European Federation of Neurological Societies or AAN definite or probable criteria for CIDP or multifocal motor neuropathy respond better to IVIg. This finding “makes sense,” Dr. Peltier said. “If we are more confident of the diagnosis, then it is very likely that IVIg will perform better.”
Among patients with type 2 diabetic neuropathy, exercise significantly improves epidermal nerve fiber density. “Exercise has been interesting, in that it may actually reverse some of the effects” of neuropathy in type 2 diabetes, Dr. Peltier said. “It may be that you will see more exercise studies in the future.”
—Jake Remaly