Botulinum toxin type B (Myobloc, NeuroBloc): a new choice in cervical dystonia

Botulinum toxin has dramatically improved the treatment of cervical dystonia. Prior to the use of botulinum toxin for many neurologic disorders, patients had few effective therapeutic options. Botulinum toxin type B (Myobloc, NeuroBloc) is a new antigenically distinct botulinum toxin with a unique structure and mechanism of action. Preclinical studies have demonstrated that im. injections of botulinum toxin type B effectively induce a dose-dependent paralysis. Controlled clinical trials have shown that it is safe and effective in alleviating symptoms associated with cervical dystonia. Given its efficacy and safety profile, the clinical use of type B toxin is anticipated to expand into other therapeutic areas.

Haplotypes and gene expression implicate the MAPT region for Parkinson disease: the GenePD Study

BACKGROUND

Microtubule-associated protein tau (MAPT) has been associated with several neurodegenerative disorders including forms of parkinsonism and Parkinson disease (PD). We evaluated the association of the MAPT region with PD in a large cohort of familial PD cases recruited by the GenePD Study. In addition, postmortem brain samples from patients with PD and neurologically normal controls were used to evaluate whether the expression of the 3-repeat and 4-repeat isoforms of MAPT, and neighboring genes Saitohin (STH) and KIAA1267, are altered in PD cerebellum.

METHODS

Twenty-one single-nucleotide polymorphisms (SNPs) in the region of MAPT on chromosome 17q21 were genotyped in the GenePD Study. Single SNPs and haplotypes, including the H1 haplotype, were evaluated for association to PD. Relative quantification of gene expression was performed using real-time RT-PCR.

RESULTS

After adjusting for multiple comparisons, SNP rs1800547 was significantly associated with PD affection. While the H1 haplotype was associated with a significantly increased risk for PD, a novel H1 subhaplotype was identified that predicted a greater increased risk for PD. The expression of 4-repeat MAPT, STH, and KIAA1267 was significantly increased in PD brains relative to controls. No difference in expression was observed for 3-repeat MAPT.

CONCLUSIONS

This study supports a role for MAPT in the pathogenesis of familial and idiopathic Parkinson disease (PD). Interestingly, the results of the gene expression studies suggest that other genes in the vicinity of MAPT, specifically STH and KIAA1267, may also have a role in PD and suggest complex effects for the genes in this region on PD risk.

Herbicide exposure modifies GSTP1 haplotype association to Parkinson onset age: the GenePD Study

BACKGROUND

Polymorphisms in the glutathione S-transferase pi gene (GSTP1), encoding GSTP1-1, a detoxification enzyme, may increase the risk of Parkinson disease (PD) with exposure to pesticides. Using the GenePD Study sample of familial PD cases, we explored whether GSTP1 polymorphisms were associated with the age at onset of PD symptoms and whether that relation was modified by exposure to herbicides.

METHODS

Seven single-nucleotide polymorphisms (SNPs) were genotyped and tested for association with PD onset age in men in three strata: no exposure to herbicides, residential exposure to herbicides, and occupational exposure to herbicides. Haplotypes were similarly evaluated in stratified analyses.

RESULTS

Three SNPs were associated with PD onset age in the group of men occupationally exposed to herbicides. Three additional SNPs had significant trends for the association of PD onset age across the herbicide exposure groups. Haplotype results also provided evidence that the relation between GSTP1 and onset age is modified by herbicide exposure. One haplotype was associated with an approximately 8-years-earlier onset in the occupationally exposed group and a 2.8-years-later onset in the nonexposed group.

CONCLUSIONS

Herbicide exposure may be an effect modifier of the relation between glutathione S-transferase pi gene polymorphisms and onset age in familial PD.

Botulinum toxin type B: An effective treatment for alleviating pain associated with cervical dystonia

Neck pain is reported in 75% is strongly associated with greater disability and decreased quality of life. Botulinum toxin type B (BoNT-B; Myobloc™) is a new botulinum toxin that has been proven safe and effective in reducing the pain, severity, and disability of patients with cervical dystonia. We analyzed a subset of efficacy data from two randomized, double blind, placebo-controlled clinical trials. The first study consisted of three treatment groups in patients who were responders to the type A toxin, including placebo (<FORMULA>n=36</FORMULA>), 5000 units (U) (<FORMULA>n=36</FORMULA>), 10,000 U (<FORMULA>n=37</FORMULA>). The second study consisted of placebo (n=38) and 10,000-U treatment groups (<FORMULA>n=39</FORMULA>) in patients not responding to the type A toxin. For this analysis, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-subscale scores for pain and three visual analog scales (Patient Analog Pain, Patient Global, and Principal Investigator Global Assessments) were evaluated. A dose-response effect was observed in the reduction of pain based on the TWSTRS-subscale scores. In both studies, mean improvements from baseline to week 4 for all patients were significant compared with placebo (<FORMULA>P<0.005</FORMULA>). BoNT-B also significantly improved mean values for all VAS assessments. Our analysis confirms that BoNT-B significantly reduces the pain associated with cervical dystonia and improves patients' overall condition. This clinical benefit suggests that BoNT-B may be useful in other pain syndromes involving involuntary muscle spasms or contractions.

Genome-wide scan for Parkinson's disease: the GenePD Study

A genome-wide scan for idiopathic PD in a sample of 113 PD-affected sibling pairs is reported. Suggestive evidence for linkage was found for chromosomes 1 (214 cM, lod = 1.20), 9 (136 cM, lod = 1.30), 10 (88 cM, lod = 1.07), and 16 (114 cM, lod = 0.93). The chromosome 9 region overlaps the genes for dopamine beta-hydroxylase and torsion dystonia. Although no strong evidence for linkage was found for any locus, these results may be of value in comparison with similar studies by others.

The safety and efficacy of botulinum toxin type B in the treatment of patients with cervical dystonia: summary of three controlled clinical trials

Cervical dystonia (CD) is characterized by abnormal, involuntary contractions of the cervical and/or shoulder muscles. Direct injection of Botulinum toxin type A (BTX-A) into the affected muscles has been used successfully to treat this condition. However, clinical resistance to BTX-A therapy develops in a limited number of patients. Moreover, an unknown proportion of treated patients have a suboptimal response to their present therapy. BTX-B is antigenically distinct from BTX-A and possesses a different mechanism of action. Three randomized, double-blind, placebo-controlled clinical trials evaluated the safety and efficacy of BTX-B (Elan's BTX-B evaluated as NeuroBloc) as a treatment for patients with CD. Patients received a single dose of BTX-B ranging from 2,500 to 10,000 U. The primary efficacy evaluation for each of these studies used the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score. Additional efficacy measures included the TWSTRS severity, disability, and pain subscale scores, as well as the Patient Analog Pain Assessment and Patient's and Physician's Global Assessments of Change. In all three studies, groups receiving BTX-B displayed statistically significant improvements in TWSTRS total score and other efficacy end points compared with those who received placebo treatment. The clinical benefits after BTX-B treatment lasted 12 to 16 weeks and were observed in both BTX-A-responsive and BTX-A-resistant patients. In general, treatment with BTX-B was well tolerated and most of the reported adverse events were of short duration, mild to moderate in severity, and anticipated. The results from the three controlled clinical trials demonstrate the safety and efficacy of BTX-B in the treatment of patients with CD, including those who are resistant to BTX-A treatment.

A randomized, controlled trial of remacemide for motor fluctuations in Parkinson's disease

BACKGROUND

Preclinical studies suggest that glutamate antagonists help ameliorate motor fluctuations in patients with PD treated with levodopa.

METHODS

In a multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study, the authors assessed the safety, tolerability, and efficacy of the glutamate receptor blocker remacemide hydrochloride in 279 patients with motor fluctuations treated with levodopa. The primary objective was to assess the short-term tolerability and safety of four dosage levels of remacemide during 7 weeks of treatment. Patients were also monitored with home diaries and the Unified PD Rating Scale (UPDRS) to collect preliminary data on treatment efficacy.

RESULTS

Remacemide was well tolerated up to a dosage of 300 mg/d on a twice daily schedule and 600 mg/d on a four times daily schedule. The most common dosage-related adverse events were dizziness and nausea, as observed in previous studies of remacemide. The percent "on" time and motor UPDRS scores showed trends toward improvement in the patients treated with 150 and 300 mg/d remacemide compared with placebo-treated patients, although these improvements were not significant.

CONCLUSION

Remacemide is a safe and tolerable adjunct to dopaminergic therapy for patients with PD and motor fluctuations. Although this study had limited power to detect therapeutic effects, the observed improvement is consistent with studies of non-human primates with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonian signs and symptoms. Additional studies are warranted to confirm these results over an extended period of observation, and to explore the potential neuroprotective effects of remacemide in slowing the progression of PD.

Safety and efficacy of NeuroBloc (botulinum toxin type B) in type A-responsive cervical dystonia

OBJECTIVE

To determine the safety and efficacy of botulinum toxin type B (BoNT/B) in patients with cervical dystonia (CD).

BACKGROUND

BoNT/B is a form of chemodenervation therapy for the treatment of patients with CD.

METHODS

The authors performed a 16-week, randomized, multicenter, double-blind, placebo-controlled trial of BoNT/B in patients with CD who continue to respond to botulinum toxin type A. Placebo, or 5,000 U or 10,000 U of BoNT/B was administered in two to four muscles involved clinically in CD. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-Total score at week 4 was the primary efficacy measure. Clinical assessments and adverse events were recorded for treatment day 1 and at weeks 2, 4, 8, 12, and 16.

RESULTS

A total of 109 patients were enrolled randomly across all three treatment groups. The mean improvement in the TWSTRS-Total scores in each group at week 4 was 4.3 (placebo), 9.3 (5,000 U), and 11.7 (10,000 U). For the prospectively defined primary contrast (10,000 U versus placebo), highly significant differences were noted for the primary (TWSTRS-Total, baseline to week 4, p = 0.0004) and supportive secondary (Patient Global Assessment, baseline to week 4, p = 0.0001) outcome measures. Improvement in pain, disability, and severity of CD occurred for patients who were treated with BoNT/B when compared with placebo-treated patients. Overall, improvements associated with BoNT/B treatment were greatest for patients who received the 10,000-U dose. The duration of treatment effect for BoNT/B was 12 to 16 weeks for both doses.

CONCLUSION

Botulinum toxin type B (NeuroBloc) is safe and efficacious at 5,000 U and 10,000 U for the management of patients with cervical dystonia.

Safety and efficacy of NeuroBloc (botulinum toxin type B) in type A-resistant cervical dystonia

OBJECTIVE

To determine the safety and efficacy of botulinum toxin type B (BoNT/B) in patients with type A-resistant cervical dystonia (CD).

BACKGROUND

Local intramuscular injections of BoNT are an effective therapy for CD. After repeated use, some patients become resistant to therapy. BoNT/B, effective in type A toxin-responsive patients, is proposed as an alternative therapy for type A-resistant patients.

METHODS

The authors performed a 16-week, double-blind, placebo-controlled trial of BoNT/B in type A-resistant patients with CD. After resistance to therapy was confirmed with the frontalis-type A test, placebo or 10,000 U BoNT/B was administered in a single session into two to four clinically involved muscles. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) was the primary efficacy measurement. TWSTRS-Total, three visual analog scales (Patient Global Assessment of Change, Principal Investigator Global Assessment of Change, Patient Analog Pain Assessment), and adverse events were assessed at baseline and weeks 2, 4, 8, 12, and 16.

RESULTS

A total of 77 patients participated (38 placebo, 39 active). Improvements in severity, disability, and pain were documented in the BoNT/B-treated group. TWSTRS-Total scores were improved in the BoNT/B-treated group at weeks 4 (p = 0.0001), 8 (p = 0.0002), and 12 (p = 0.0129). All three visual analog scales demonstrated improvements at week 4 (p < 0.0001, 0.0001, and 0.001). A Kaplan-Meier analysis supported a duration of effect of 12 to 16 weeks in the active group. Dry mouth and dysphagia were self-limited adverse effects, reported more commonly in the BoNT/B group.

CONCLUSIONS

Botulinum toxin type B (BoNT/B) (NeuroBloc) is safe and efficacious for the management of patients with type A-resistant cervical dystonia with an estimated duration of treatment effect of 12 to 16 weeks.

Randomized, placebo-controlled study of tolcapone in patients with fluctuating Parkinson disease treated with levodopa-carbidopa. Tolcapone Fluctuator Study Group III

OBJECTIVE

To assess the efficacy and tolerability of the catechol-O-methyltransferase inhibitor tolcapone in reducing "off/on" fluctuations in levodopa-treated parkinsonian patients.

DESIGN

A randomized, double-blind, placebo-controlled, parallel-group study.

SETTING

Fifteen Parkinson disease clinics.

PATIENTS

Two hundred fifteen referred outpatients with Parkinson disease who showed predictable end-of-dose motor fluctuations that were not controlled by a stable levodopa-carbidopa (Sinemet) regimen of at least 4 weeks' duration.

INTERVENTIONS

In addition to their usual levodopa-carbidopa regimen, patients received placebo or tolcapone, 100 or 200 mg, 3 times daily orally for 6 weeks.

PRIMARY OUTCOME MEASURE

Change in daily off/on time.

RESULTS

Tolcapone, 100 and 200 mg 3 times daily, reduced off time by 2.0 and 2.5 hours per day, respectively, and increased on time by 2.1 and 2.3 hours per day, respectively (P<.001 vs placebo). Investigators' global measures of disease severity indicated that significantly more tolcapone-treated patients had reduced wearing off and symptom severity (P<.001 vs placebo). No significant change in quality-of-life measures occurred. Clinical improvements occurred despite a reduction in total daily levodopa dose of 185.5 mg (23%) in the tolcapone, 100 mg 3 times daily, group and 251.5 mg (29%) in the 200 mg 3 times daily group. Principal adverse events (mainly dyskinesia and nausea) were levodopa related, were not treatment limiting, and were seldom reported as reasons for withdrawal. The frequency of withdrawals because of adverse events was similar in all groups (3% to 7%).

CONCLUSIONS

Tolcapone was well tolerated and substantially increased on time and reduced off time in patients with fluctuating Parkinson disease. Additionally, levodopa requirements were significantly decreased.

Botulinum toxin type B: a double-blind, placebo-controlled, safety and efficacy study in cervical dystonia

We enrolled and treated 122 patients with idiopathic cervical dystonia in a double-blind, placebo-controlled safety and efficacy study of botulinum toxin type B (BotB). Both A-responsive and A-resistant patients were enrolled. Patients received intramuscular injections of either BotB (2,500 U, 5,000 U, or 10,000 U) or placebo. The primary outcome measure of efficacy was the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-Total score at 4 weeks following study drug administration. Secondary measures of efficacy were TWSTRS-Severity, -Disability, and -Pain subscale scores, and Analog Pain Assessment, Investigator Global Assessment, Patient Global Assessment, and Sickness Impact Profile scores. Duration of effect was estimated with an intent-to-treat analysis of responders. Safety measures included clinical parameters, laboratory tests, and adverse events. The primary and most of the secondary analyses indicated a statistically significant treatment effect and a dose response. BotB is safe, well tolerated, and efficacious in the treatment of cervical dystonia at the doses tested.

Pallidotomy increases activity of motor association cortex in Parkinson's disease: a positron emission tomographic study

Stereotactic posteroventral pallidotomy can improve motor performance in Parkinson's disease. Interruption of inhibitory pallidal projections to ventrolateral thalamus, components of a cortical-basal ganglia motor loop allows for this clinical benefit. We hypothesized that pallidotomy would lead to increased movement related activity in motor cortical areas receiving projections from ventrolateral thalamus. This was tested in 6 Parkinson's disease patients who underwent stereotactic posteroventral pallidotomy. Each patient was imaged with positron emission tomography (PET) measures of regional cerebral blood flow (rCBF) during performance of a simple prehension task and at rest. Scans were acquired before and 17 weeks after surgery. After pallidotomy, movement-related changes of rCBF increased significantly in both the supplementary motor area (SMA) and premotor cortex but not in primary motor cortex. The results demonstrate the importance of pallidothalamic circuitry for regulating volitional movements and confirm that disruption of inhibitory input to the ventrolateral thalamus can augment movement-related activity in motor association areas.

Ventroposterior medial pallidotomy in patients with advanced Parkinson's disease

In a preliminary study, the effects of ventroposterior medial pallidotomy were evaluated in five patients with advanced Parkinson's disease in whom medical therapy had failed. The mean age was 67.0 +/- 5.6 years, and the mean Hoehn and Yahr stage when "off" was 3.9 +/- 1.3. Three patients received unilateral pallidotomies; two of these received another pallidotomy after 8 weeks. Two other patients received staged bilateral pallidotomies. No significant differences in overall function could be seen before and after the first surgical procedure. All three patients with peak-dose dyskinesias or dystonia had marked contralateral reduction in these symptoms. Ventroposterior medial pallidotomy can ameliorate peak-dose dyskinesias in patients with advanced Parkinson's disease. Overall function improvement is not remarkable.

Adductor laryngeal breathing dystonia in a patient with lubag (X-linked dystonia-Parkinsonism syndrome)

We report a patient with Lubag (X-linked dystonia-parkinsonism) who presented with severe respiratory stridor from adductor laryngeal breathing dystonia. Emergency tracheostomy was necessary, and subsequent laryngeal injection with botulinum toxin led to worsening aspiration. Botulinum toxin injection for severe lingual dystonia was successful.

Psychopharmacologic and clinical correlates of attention in chronic schizophrenia

Distractibility and reaction time were measured in 25 clinically stable chronic schizophrenic subjects receiving psychotropic medications. Higher serum neuroleptic levels were associated with lessened distractibility. Extrapyramidal side effects and level of symptoms were each related to slow and variable reaction times.

Serum levels of anticholinergic drugs and impaired recent memory in chronic schizophrenic patients

The authors tested working or recent memory in 24 stabilized schizophrenic outpatients who were taking psychotropic medication. Memory performance did not correlate with severity of schizophrenic symptoms, verbal IQ, or serum neuroleptic levels, but there was a significant inverse correlation between serum anticholinergic levels and performance on the memory task. The results suggest that therapeutic doses of anticholinergics may cause subtle impairments of cognitive functions.

Intracranial self-stimulation in 3-day-old rat pups

Three-day-old rat pups with electrodes directed at the medial forebrain bundle at the level of the lateral hypothalamic area were trained to push a paddle to receive electrical brain stimulation. Pups receiving stimulation that was contingent on lifting the paddle responded more frequently than did control pups and also learned a two-choice spatial discrimination task that was rewarded with brain stimulation. The experiments indicate that a neural substrate in the area of the medial forebrain bundle is involved in the central mediation of reinforcement in the rat pup.