This randomized, placebo-controlled, double-blind study was the first to evaluate the antidepressant efficacy, safety, and tolerability of an NR2B subunit-selective N-methyl-D-aspartate receptor antagonist, CP-101,606. Subjects had major depression, according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria and a history of treatment refractoriness to least 1 adequate trial of a selective serotonin reuptake inhibitor. The study had 2 treatment periods. In period 1, subjects first received a 6-week open-label trial of paroxetine and a single-blind, intravenous placebo infusion. Period 1 nonresponders (n = 30) then received a randomized double-blind single infusion of CP-101,606 or placebo plus continued treatment with paroxetine for up to an additional 4 weeks (period 2). Depression severity was assessed using the Montgomery-Asberg Depression Rating Scale and 17-item Hamilton Depression Rating Scale. On the prespecified main outcome measure (change from baseline in the Montgomery-Asberg Depression Rating Scale total score at day 5 of period 2), CP-101,606 produced a greater decrease than did placebo (mean difference, 8.6; 80% confidence interval, -12.3 to -4.5) (P < 0.10). Hamilton Depression Rating Scale response rate was 60% for CP-101,606 versus 20% for placebo. Seventy-eight percent of CP-101,606-treated responders maintained response status for at least 1 week after the infusion. CP-101,606 was safe, generally well tolerated, and capable of producing an antidepressant response without also producing a dissociative reaction. Antagonism of the NR2B subtype of the N-methyl-D-aspartate receptor may be a fruitful target for the development of a new antidepressant with more robust effects and a faster onset compared with those currently available and capable of working when existing antidepressants do not.

We have previously identified the opium alkaloid noscapine as a microtubule interacting agent that binds stoichiometrically to tubulin and alters its conformation. Here we show that, unlike many other microtubule inhibitors, noscapine does not significantly promote or inhibit microtubule polymerization. Instead, it alters the steady-state dynamics of microtubule assembly, primarily by increasing the amount of time that the microtubules spend in an attenuated (pause) state. Further studies reveal that even at high concentrations, noscapine does not alter the tubulin polymer/monomer ratio in HeLa cells. Cells treated with noscapine arrest at mitosis with nearly normal bipolar spindles. Strikingly, although most of the chromosomes in these cells are aligned at the metaphase plate, the rest remain near the spindle poles, both of which exhibit loss of tension across kinetochore pairs. Furthermore, levels of the spindle checkpoint proteins Mad2, Bub1, and BubR1 decrease by 138-, 3.7-, and 3.9-fold, respectively, at the kinetochore region upon chromosome alignment. Our results thus suggest that an exquisite control of microtubule dynamics is required for kinetochore tension generation and chromosome alignment during mitosis. Our data also support the idea that Mad2 and Bub1/BubR1 respond to kinetochore-microtubule attachment and/or tension to different degrees.

The opium alkaloid noscapine is a commonly used antitussive agent available in Europe, Asia, and South America. Although the mechanism by which it suppresses coughing is currently unknown, it is presumed to involve the central nervous system. In addition to its antitussive action, noscapine also binds to tubulin and alters microtubule dynamics in vitro and in vivo. In this study, we show that noscapine inhibits the proliferation of rat C6 glioma cells in vitro (IC 50 ‫؍‬ 100 M) and effectively crosses the blood-brain barrier at rates similar to the ones found for agents such as morphine and [Met]enkephalin that have potent central nervous system activity (P < 0.05). Daily oral noscapine treatment (300 mg/kg) administered to immunodeficient mice having stereotactically implanted rat C6 glioblasoma into the striatum revealed a significant reduction of tumor volume (P < 0.05). This was achieved with no identifiable toxicity to the duodenum, spleen, liver, or hematopoietic cells as determined by pathological microscopic examination of these tissues and flow cytometry. Furthermore, noscapine treatment resulted in little evidence of toxicity to dorsal root ganglia cultures as measured by inhibition of neurite outgrowth and yielded no evidence of peripheral neuropathy in animals. However, evidence of vasodilation was observed in noscapine-treated brain tissue. These unique properties of noscapine, including its ability to cross the blood-brain barrier, interfere with microtubule dynamics, arrest tumor cell division, reduce tumor growth, and minimally affect other dividing tissues and peripheral nerves, warrant additional investigation of its therapeutic potential.

Glutamate antagonists decrease dyskinesia and augment the antiparkinsonian effects of levodopa in animal models of Parkinson’s disease (PD). In a randomized, double-blind, placebo-controlled clinical trial we investigated the acute effects of placebo and two doses of a NR2B subunit selective NMDA glutamate antagonist, CP-101,606, on the response to two-hour levodopa infusions in 12 PD subjects with motor fluctuations and dyskinesia. Both doses of CP-101,606 reduced the maximum severity of levodopa-induced dyskinesia approximately 30% but neither dose improved parkinsonism. CP-101,606 was associated with a dose-related dissociation and amnesia. These results support the hypothesis that glutamate antagonists may be useful antidyskinetic agents. However, future studies will have to determine if the benefits of dyskinesia suppression can be achieved without adverse cognitive effects.

The modified Rankin Scale (mRS), a 7-level, clinician-reported, measure of global disability, is the most widely employed outcome scale in acute stroke trials. The scale’s original development preceded the advent of modern clinimetrics, but substantial subsequent work has been performed to enable the mRS to meet robust contemporary scale standards. Prior research and consensus recommendations have focused on modernizing 2 aspects of the mRS: operationalized assignment of scale scores and statistical analysis of scale distributions. Another important characteristic of the mRS still requiring elaboration and specification to contemporary clinimetric standards is the Naming of scale outcomes. Recent clinical trials have used a bewildering variety, often mutually contradictory, of rubrics to describe scale states. Understanding of the meaning of mRS outcomes by clinicians, patients, and other clinical trial stakeholders would be greatly enhanced by use of a harmonized, uniform set of labels for the distinctive mRS outcomes that would be used consistently across trials. This statement advances such recommended rubrics, developed by the Stroke Therapy Academic Industry Roundtable collaboration using an iterative, mixed-methods process. Specific guidance is provided for health state terms (eg, Symptomatic but Nondisabled for mRS score 1; requires constant care for mRS score 5) and valence terms (eg, excellent for mRS score 1; very poor for mRS score 5) to employ for 23 distinct numeric mRS outcomes, including: all individual 7 mRS levels; all 12 positive and negative dichotomized mRS ranges, positive and negative sliding dichotomies; and utility-weighted analysis of the mRS.

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A 2-hour infusion of 0.1 to 10 mg/kg ponezumab was well tolerated in subjects with mild-to-moderate AD. Plasma pharmacokinetic profile was approximately linear. Plasma Aβ increased with dose, and CSF Aβ increased at the highest dose, suggesting that intravenous ponezumab alters central Aβ levels.

The objective of these studies was to assess the efficacy and safety of pregabalin in the treatment of human immunodeficiency virus (HIV)-associated neuropathic pain. Patients with HIV-associated distal sensory polyneuropathy (DSP) were randomized to treatment with flexible-dose pregabalin (150-600 mg/day) or placebo for 17 weeks in a single-blind, placebo lead-in, randomized, double-blind, parallel-group, placebo-controlled multinational trial. The primary efficacy outcome was the change in mean pain score on an 11-point numeric rating scale (NRS) from baseline to study endpoint. Participants who completed this trial were invited to participate in a 6-month open-label extension study with pregabalin. Of the 377 patients enrolled in the randomized controlled trial (pregabalin, n=183; placebo, n=194), 68.4% completed treatment. In the open-label extension, 217 patients were treated and 59.4% completed treatment. Both studies were terminated by the sponsor after a preplanned interim analysis indicated trial futility. At endpoint, the change from baseline in least-squares mean NRS pain scores in the intent-to-treat population was -2.04 for pregabalin versus -2.11 for placebo (P=.709). There were no significant differences between the pregabalin and placebo groups in the secondary efficacy measures. Incidence of adverse events was lower than seen in previous pregabalin studies. Overall, this trial did not show pregabalin to be more efficacious than placebo in treating HIV-associated DSP. Studies such as these, which fail to support their primary hypotheses, may be important in informing the methodology of future trials, especially when novel approaches to limit variability in the control group are included. ClinicalTrials.gov identifiers: NCT01049217 and NCT01145417.