Miriam Freimer

Randomized controlled trial of IVIg in untreated chronic inflammatory demyelinating polyradiculoneuropathy

Objective: To determine the efficacy of IV immunoglobulin (IVIg) given patients with untreated chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Methods: 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). Results: 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). Conclusions: 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.

Thalidomide-induced neuropathy

Background: Thalidomide is effective for the treatment of some refractory dermatologic and oncologic diseases. Toxic neuropathy limits its use, as embryopathy can be avoided by contraceptive measures. Objective: To describe the clinical, electrophysiologic, and pathologic features of thalidomide-induced peripheral neuropathy. Methods: Clinical and electrophysiologic examinations were performed in seven patients with thalidomide-induced peripheral neuropathy. Thalidomide was used for graft-vs-host disease, pyoderma gangrenosum, and discoid lupus with dosages ranging from 100 to 1,200 mg/day for 5 to 16 months (cumulative dosages of 24 to 384 g). Results: All seven patients had clinical and electrophysiologic evidence of a sensory more than motor, axonal, length-dependent polyneuropathy that presented as painful paresthesias or numbness. Sural nerve biopsies, done in three patients, showed evidence of Wallerian degeneration and loss of myelinated fibers. The symptoms, signs, and electrophysiologic data correlated with total cumulative dose of thalidomide. Conclusions: Thalidomide induces a dose-dependent sensorimotor length-dependent axonal neuropathy; it should be judiciously used with close neurologic monitoring.

A randomized, double‐blind, placebo‐controlled phase II study of eculizumab in patients with refractory generalized myasthenia gravis

Introduction: Complement activation at the neuromuscular junction is a primary cause of acetylcholine receptor loss and failure of neuromuscular transmission in myasthenia gravis (MG). Eculizumab, a humanized monoclonal antibody, blocks the formation of terminal complement complex by specifically preventing the enzymatic cleavage of complement 5 (C5). Methods: This study was a randomized, double‐blind, placebo‐controlled, crossover trial involving 14 patients with severe, refractory generalized MG (gMG). Results: Six of 7 patients treated with eculizumab for 16 weeks (86%) achieved the primary endpoint of a 3‐point reduction in the quantitative myasthenia gravis (QMG) score. Examining both treatment periods, the overall change in mean QMG total score was significantly different between eculizumab and placebo (P = 0.0144). After assessing data obtained from all visits, the overall change in mean QMG total score from baseline was found to be significantly different between eculizumab and placebo (P < 0.0001). Eculizumab was well tolerated. Conclusion: The data suggest that eculizumab may have a role in treating severe, refractory MG. Muscle Nerve, 2013

Randomized, controlled trial of intravenous immunoglobulin in myasthenia gravis.

We initiated a randomized, double‐blinded, placebo‐controlled trial of intravenous immunoglobulin (IVIG) treatment in myasthenia gravis (MG). Patients received IVIG 2 gm/kg at induction and 1 gm/kg after 3 weeks vs. 5% albumin placebo. The primary efficacy measurement was the change in the quantitative MG Score (QMG) at day 42. Fifteen patients were enrolled (6 to IVIG; 9 to placebo) before the study was terminated because of insufficient IVIG inventories. At day 42, there was no significant difference in primary or secondary outcome measurements between the two groups. In a subsequent 6‐week open‐label study of IVIG, positive trends were observed.

A genome-wide association study of myasthenia gravis

IMPORTANCE Myasthenia gravis is a chronic, autoimmune, neuromuscular disease characterized by fluctuating weakness of voluntary muscle groups. Although genetic factors are known to play a role in this neuroimmunological condition, the genetic etiology underlying myasthenia gravis is not well understood. OBJECTIVE To identify genetic variants that alter susceptibility to myasthenia gravis, we performed a genome-wide association study. DESIGN, SETTING, AND PARTICIPANTS DNA was obtained from 1032 white individuals from North America diagnosed as having acetylcholine receptor antibody-positive myasthenia gravis and 1998 race/ethnicity-matched control individuals from January 2010 to January 2011. These samples were genotyped on Illumina OmniExpress single-nucleotide polymorphism arrays. An independent cohort of 423 Italian cases and 467 Italian control individuals were used for replication. MAIN OUTCOMES AND MEASURES We calculated P values for association between 8,114,394 genotyped and imputed variants across the genome and risk for developing myasthenia gravis using logistic regression modeling. A threshold P value of 5.0×10(-8) was set for genome-wide significance after Bonferroni correction for multiple testing. RESULTS In the overall case-control cohort, we identified association signals at CTLA4 (rs231770; P=3.98×10(-8); odds ratio, 1.37; 95% CI, 1.25-1.49), HLA-DQA1 (rs9271871; P=1.08×10(-8); odds ratio, 2.31; 95% CI, 2.02-2.60), and TNFRSF11A (rs4263037; P=1.60×10(-9); odds ratio, 1.41; 95% CI, 1.29-1.53). These findings replicated for CTLA4 and HLA-DQA1 in an independent cohort of Italian cases and control individuals. Further analysis revealed distinct, but overlapping, disease-associated loci for early- and late-onset forms of myasthenia gravis. In the late-onset cases, we identified 2 association peaks: one was located in TNFRSF11A (rs4263037; P=1.32×10(-12); odds ratio, 1.56; 95% CI, 1.44-1.68) and the other was detected in the major histocompatibility complex on chromosome 6p21 (HLA-DQA1; rs9271871; P=7.02×10(-18); odds ratio, 4.27; 95% CI, 3.92-4.62). Association within the major histocompatibility complex region was also observed in early-onset cases (HLA-DQA1; rs601006; P=2.52×10(-11); odds ratio, 4.0; 95% CI, 3.57-4.43), although the set of single-nucleotide polymorphisms was different from that implicated among late-onset cases. CONCLUSIONS AND RELEVANCE Our genetic data provide insights into aberrant cellular mechanisms responsible for this prototypical autoimmune disorder. They also suggest that clinical trials of immunomodulatory drugs related to CTLA4 and that are already Food and Drug Administration approved as therapies for other autoimmune diseases could be considered for patients with refractory disease.

SMA valiant trial: A prospective, double-blind, placebo-controlled trial of valproic acid in ambulatory adults with spinal muscular atrophy

Introduction: An open‐label trial suggested that valproic acid (VPA) improved strength in adults with spinal muscular atrophy (SMA). We report a 12‐month, double‐blind, cross‐over study of VPA in ambulatory SMA adults. Methods: There were 33 subjects, aged 20–55 years, included in this investigation. After baseline assessment, subjects were randomized to receive VPA (10–20 mg/kg/day) or placebo. At 6 months, patients were switched to the other group. Assessments were performed at 3, 6, and 12 months. The primary outcome was the 6‐month change in maximum voluntary isometric contraction testing with pulmonary, electrophysiological, and functional secondary outcomes. Results: Thirty subjects completed the study. VPA was well tolerated, and compliance was good. There was no change in primary or secondary outcomes at 6 or 12 months. Conclusions: VPA did not improve strength or function in SMA adults. The outcomes used are feasible and reliable and can be employed in future trials in SMA adults. Muscle Nerve 49: 187–192, 2014

A novel PMP22 point mutation causing HNPP phenotype Studies on nerve xenografts

Background: Hereditary neuropathy with liability to pressure palsies (HNPP) in most cases is caused by a deletion in chromosome 17p11.2-12 or, rarely, mutations resulting in a functional loss of one copy of the peripheral myelin protein 22 (PMP22) gene. Point mutations that lie deep within transmembrane(TM) domains causing major structural changes in PMP22 are associated with severe neuropathy. Methods: A 25-year-old asymptomatic woman with a normal neurologic examination volunteered as a control subject. Electrophysiologic studies showed multiple entrapment neuropathies, prompting a search for a genetic defect. In addition, sural nerve fascicles from the subject were grafted into the cut ends of the sciatic nerve of nude mice and studied at 2, 6, and 8 weeks and compared with controls. Results: Direct sequencing of the PMP22 gene revealed a G→A transition at position 202 in axon 3 of the PMP22 gene. To determine if this was a causative mutation rather than a polymorphism, 102 DNA samples from controls were studied; none showed a similar base pair change. In the nerve xenografts, there was a marked delay at the onset of myelination and an impairment in the regenerative capacity of the nude mice axons engulfed by the mutant human Schwann cells. The axon tips were enlarged and demonstrated neurofilament density increase. Neurofilament density distribution histograms were bimodal in xenografts as well as in the subjects sural nerve. Conclusion: This study provides unequivocal evidence that a base pair change causing a Val30Met substitution at the junction of the first TM domain and the extracellular loop of PMP22 results in the HNPP phenotype.

Relationship Between Intraneural Vascular Flow Measured With Sonography and Carpal Tunnel Syndrome Diagnosis Based on Electrodiagnostic Testing

The purpose of this study was to document and analyze intraneural vascular flow within the median nerve using power and spectral Doppler sonography and to determine the relationship of this vascular flow with diagnosis of carpal tunnel syndrome based on electrodiagnostic testing.

Screening for Carpal Tunnel Syndrome Using Sonography

The use of sonography in musculoskeletal research and clinical applications is increasing; however, measurement techniques for diagnosing carpal tunnel syndrome with sonography continue to be inconsistent. Novel methods of measurement using internal comparisons to identify swelling of the median nerve require investigation and comparison to currently used techniques.

Chemotherapy-induced peripheral neuropathy: an update on the current understanding.

Chemotherapy-induced peripheral neuropathy is a common side effect of selected chemotherapeutic agents. Previous work has suggested that patients often under report the symptoms of chemotherapy-induced peripheral neuropathy and physicians fail to recognize the presence of such symptoms in a timely fashion. The precise pathophysiology that underlies chemotherapy-induced peripheral neuropathy, in both the acute and the chronic phase, remains complex and appears to be medication specific. Recent work has begun to demonstrate and further clarify potential pathophysiological processes that predispose and, ultimately, lead to the development of chemotherapy-induced peripheral neuropathy. There is increasing evidence that the pathway to neuropathy varies with each agent. With a clearer understanding of how these agents affect the peripheral nervous system, more targeted treatments can be developed in order to optimize treatment and prevent long-term side effects.