Pregabalin in Patients With Painful Diabetic Peripheral Neuropathy Using an NSAID for Other Pain Conditions: A Double-Blind Crossover Study.

OBJECTIVES: To evaluate pregabalin's efficacy and safety versus placebo to reduce pain in patients with diabetic peripheral neuropathy (DPN) using a concomitant nonsteroidal anti-inflammatory drug. MATERIALS AND METHODS: In a randomized, double-masked, 14-week, 2-period, crossover study, patients with painful DPN using a nonsteroidal anti-inflammatory drug for non-DPN-related pain received 150 to 300 mg/d pregabalin or placebo (period 1); 14-day washout; then, the opposite therapy (period 2). Endpoints included weekly change in DPN pain score, sleep interference, adverse events, and patient-reported outcomes. RESULTS: Patients with similar baseline characteristics were randomized (period 1) to 1 of the 2 following possible sequences: pregabalin→placebo (n=154) or placebo→pregabalin (n=147). Results of the primary efficacy measure, mean weekly DPN pain at endpoint, showed no significant difference between pregabalin and placebo. However, 1 sensitivity analysis (mixed-model repeated measures) found greater pain score reductions with pregabalin than placebo at weeks 2 to 4 and overall (all P<0.05). One secondary endpoint analysis, mean treatment difference in DPN-related sleep interference, favored pregabalin over placebo (P=0.0009). Other sensitivity and secondary analyses were nonsignificant. Treatment-emergent adverse events were consistent with the known safety profile of pregabalin. DISCUSSION: Pregabalin (vs. placebo) showed overall improvements in sleep, pain reduction in 1 sensitivity analysis, and was well tolerated. Potential factors that may have confounded the ability to detect a treatment difference in DPN pain reduction (high placebo response, carryover effect, short washout period, or pregabalin dose) are discussed in the context of future studies.

Efficacy and Safety of Pregabalin in the Treatment of Patients With Painful Diabetic Peripheral Neuropathy and Pain on Walking.

OBJECTIVES: This randomized, double-blind, placebo-controlled, multicenter, 2-period crossover study (two 6-week treatment periods separated by a 2-week washout period) evaluated the efficacy and safety of pregabalin (150 to 300 mg/d) for treatment of pain and pain on walking in patients with painful diabetic peripheral neuropathy (DPN) who experienced pain while walking. METHODS: Co-primary efficacy endpoints were: (1) mean pain score (last 7 daily pain diary scores, 0 to 10 numeric rating scale at end of each treatment period) and (2) DPN pain on walking (0 to 10 numeric rating scale immediately after walking 50 feet [15.2 m] on flat surface). Secondary endpoints included other pain parameters, patient-reported sleep, health-related quality of life, and safety measures. RESULTS: Two hundred three patients were treated (pregabalin, n=198; placebo, n=186), with no statistically significant treatment difference for pregabalin versus placebo in the co-primary efficacy endpoints, mean DPN pain (P=0.0656) and mean DPN pain on walking (P=0.412). A carryover effect was observed. Analysis of co-primary endpoints for period 1 showed significant treatment difference for DPN pain (P=0.034) and DPN pain on walking (P=0.001). Treatment with pregabalin resulted in significant improvements versus placebo on prespecified patient global impression of change (end of period 1; P=0.002), and sleep interference rating scale (end of period 2; P=0.011). Adverse events were more frequent with pregabalin than with placebo and caused discontinuation in 13 (6.6%) pregabalin patients versus 5 (2.7%) placebo patients. DISCUSSION: Failure to meet the co-primary objectives may be related to carryover effect from period 1 to period 2, lower pregabalin dose (150 to 300 mg/d), and/or placebo response in painful DPN.

Pregabalin monotherapy in patients with partial-onset seizures: a historical-controlled trial.

OBJECTIVE: To assess pregabalin monotherapy for partial-onset seizures using a historical-controlled conversion-to-monotherapy design. METHODS: Adults with inadequately controlled partial-onset seizures while receiving 1 or 2 antiepileptic drugs during an 8-week prospective baseline were randomized to double-blind monotherapy with pregabalin 600 or 150 mg/d (4:1) for 20 weeks (8-week conversion and 12-week monotherapy period). The primary endpoint was the seizure-related exit rate for pregabalin 600 mg/d, based on discontinuations due to predefined criteria. Efficacy was declared if the upper limit of the 95% confidence interval for the exit rate was below a historical-control threshold of 74%, with stepwise evaluation using a threshold of 68%. RESULTS: The trial was stopped early for positive efficacy after an interim analysis in 125 patients. The full study population included 161 patients, with 148 evaluable for efficacy. The mean time since epilepsy diagnosis was 14 years. Overall, 54.3% (600 mg/d) and 46.9% (150 mg/d) of patients completed 20 weeks of double-blind treatment. Seizure-related exit rate in the 600 mg/d group (27.5%; 95% confidence interval, 17.8%-37.2%) was significantly below the 74% and 68% thresholds (p < 0.001 for both). Eight patients on 600 mg/d and 2 on 150 mg/d were seizure-free throughout pregabalin monotherapy. Pregabalin's overall safety profile was consistent with prior trials. CONCLUSIONS: Pregabalin monotherapy was safe and efficacious for patients with inadequately controlled partial-onset seizures. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that patients with inadequately controlled partial-onset seizures switched to pregabalin monotherapy have fewer seizure-related exit events compared with historical controls switched to pseudo-placebo monotherapy.

Efficacy and safety of pregabalin versus lamotrigine in patients with newly diagnosed partial seizures: a phase 3, double-blind, randomised, parallel-group trial.

BACKGROUND: Efficacious and safe monotherapy options are needed for adult patients with newly diagnosed epilepsy. As an adjunctive treatment for partial seizures, pregabalin compares favourably with lamotrigine and is an effective, approved treatment. We studied the efficacy and safety of pregabalin as monotherapy, using a design that complied with European regulatory requirements and International League Against Epilepsy guidelines. METHODS: This phase 3, double-blind, randomised, non-inferiority study compared the efficacy and tolerability of pregabalin and lamotrigine monotherapy in patients with newly diagnosed partial seizures at 105 centres, mostly in Europe and Asia. Randomisation to treatment groups (1:1 ratio) was by a computer-generated pseudorandom code (random permuted blocks), with patients sequentially assigned numbers by telephone. Investigators, site staff, and patients were masked to the assigned treatment. After randomisation, patients were titrated to either 75 mg oral pregabalin or 50 mg oral lamotrigine twice daily during a 4-week dose-escalation phase, followed by a 52-week efficacy assessment phase during which the daily dose could be increased as needed to a maximum of 600 mg and 500 mg, respectively. The primary efficacy endpoint was the proportion of patients who remained seizure-free for 6 or more continuous months during the efficacy assessment phase; analysis included all patients who were randomly assigned to treatment groups and received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, number NCT00280059. FINDINGS: 660 patients were randomly assigned to treatment groups (330 pregabalin, 330 lamotrigine), of whom 622 entered the efficacy assessment phase (314 pregabalin, 308 lamotrigine). Fewer patients in the pregabalin group than in the lamotrigine group became seizure-free for 6 or more continuous months (162 [52%] vs 209 [68%]; difference in proportion, -0·16, 95% CI -0·24 to -0·09). The overall incidence of adverse events was similar between the groups and consistent with that in previous studies; dizziness (55 [17%] vs 45 [14%] patients), somnolence (29 [9%] vs 14 [4%]), fatigue (27 [8%] vs 19 [6%]), and weight increase (21 [6%] vs 7 [2%]) were numerically more common in the pregabalin group than in the lamotrigine group. INTERPRETATION: Pregabalin has similar tolerability but seems to have inferior efficacy to lamotrigine for the treatment of newly diagnosed partial seizures in adults. Inferior efficacy of pregabalin might have been attributable to limitations in the study design, as treatment doses might have not been optimised adequately or early enough. FUNDING: Pfizer Inc.

The effect of the selective NMDA receptor antagonist traxoprodil in the treatment of traumatic brain injury.

Traumatic brain injury (TBI) remains a major public health problem, and there is a great medical need for a pharmacological treatment that could improve long-term outcome. The excitatory neurotransmitter, glutamate, has been implicated in processes leading to neurodegeneration. Traxoprodil (CP-101,606) is a novel and potent glutamate receptor antagonist that is highly selective for the NR2B subunit of the NMDA receptor; it has been shown to be neuroprotective in animal models of brain injury and ischemia. A randomized, double-blind, placebo-controlled study was therefore conducted to assess the efficacy and safety of a 72-h infusion of traxoprodil compared to placebo in subjects with computed tomography scan evidence of severe TBI (GCS 4-8). A total of 404 males and non-pregnant females, aged 16-70, were treated within 8 h of injury. At baseline, subjects were stratified by motor score severity. The results showed that a greater proportion of the traxoprodil-treated subjects had a favorable outcome on the dichotomized Glasgow Outcome Scale (dGOS) at 6 months (delta 5.5%, OR 1.3, p = 0.21, 95% CI:[0.85, 2.06]) and at last visit (delta 7.5%, OR 1.47, p = 0.07, 95% CI:[0.97, 2.25]). The mortality rate with traxoprodil treatment was 7% less than with placebo treatment (OR 1.45, p = 0.08, 95% CI:[0.96, 2.18]). Differences between treatment groups were more pronounced in the severest subset (delta 11.8% for the dGOS at last visit and delta 16.6% for mortality). Traxoprodil was well tolerated. Although these results are intriguing, no definitive claim of efficacy can be made for traxoprodil for the treatment of severe TBI.

Clinical trials in head injury.

Traumatic brain injury (TBI) remains a major public health problem globally. In the United States the incidence of closed head injuries admitted to hospitals is conservatively estimated to be 200 per 100,000 population, and the incidence of penetrating head injury is estimated to be 12 per 100,000, the highest of any developed country in the world. This yields an approximate number of 500,000 new cases each year, a sizeable proportion of which demonstrate significant long-term disabilities. Unfortunately, there is a paucity of proven therapies for this disease. For a variety of reasons, clinical trials for this condition have been difficult to design and perform. Despite promising pre-clinical data, most of the trials that have been performed in recent years have failed to demonstrate any significant improvement in outcomes. The reasons for these failures have not always been apparent and any insights gained were not always shared. It was therefore feared that we were running the risk of repeating our mistakes. Recognizing the importance of TBI, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored a workshop that brought together experts from clinical, research, and pharmaceutical backgrounds. This workshop proved to be very informative and yielded many insights into previous and future TBI trials. This paper is an attempt to summarize the key points made at the workshop. It is hoped that these lessons will enhance the planning and design of future efforts in this important field of research.