Randomized, controlled, proof-of-concept trial of MK-7622 in Alzheimer's disease

INTRODUCTION

We evaluated the selective M1 muscarinic positive allosteric modulator, MK-7622, as adjunctive cognitive enhancing therapy in individuals with Alzheimer's disease.

METHODS

A randomized, double-blind, proof-of-concept trial was performed. Participants with mild-to-moderate Alzheimer's disease, being treated with an acetylcholinesterase inhibitor, were randomized 1:1 to 45 mg of MK-7622 or placebo for 24 weeks. Endpoints included the mean change from baseline in Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog₁₁) at 12 weeks and Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory at 24 weeks.

RESULTS

Two hundred forty participants were randomized. The trial was stopped for futility after meeting prospectively defined stopping criteria. MK-7622 did not improve cognition at 12 weeks (group difference in ADAS-Cog₁₁: 0.18 [95% confidence interval: -1.0 to 1.3]) or function at 24 weeks (group difference in Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory: 0.06 [95% confidence interval: -2.4 to 2.5]). More participants taking MK-7622 discontinued study medication because of adverse events than those taking placebo (16% vs 6%) and who experienced cholinergically related adverse events (21% vs 8%).

DISCUSSION

MK-7622 (45 mg) does not improve cognition or function when used as adjunctive therapy in mild-to-moderate Alzheimer's disease.

Suvorexant in Patients With Insomnia: Results From Two 3-Month Randomized Controlled Clinical Trials

BACKGROUND

Suvorexant is an orexin receptor antagonist for treatment of insomnia. We report results from two pivotal phase 3 trials.

METHODS

Two randomized, double-blind, placebo-controlled, parallel-group, 3-month trials in nonelderly (18-64 years) and elderly (≥65 years) patients with insomnia. Suvorexant doses of 40/30 mg (nonelderly/elderly) and 20/15 mg (nonelderly/elderly) were evaluated. The primary focus was 40/30 mg, with fewer patients randomized to 20/15 mg. There was an optional 3-month double-blind extension in trial 1. Each trial included a 1-week, randomized, double-blind run-out after double-blind treatment to assess withdrawal/rebound. Efficacy was assessed at week 1, month 1, and month 3 by patient-reported subjective total sleep time and time to sleep onset and in a subset of patients at night 1, month 1, and month 3 by polysomnography end points of wakefulness after persistent sleep onset and latency to onset of persistent sleep (LPS). One thousand twenty-one patients were randomized in trial 1 and 1019 patients in trial 2.

RESULTS

Suvorexant 40/30 mg was superior to placebo on all subjective and polysomnography end points at night 1/week 1, month 1, and month 3 in both trials, except for LPS at month 3 in trial 2. Suvorexant 20/15 mg was superior to placebo on subjective total sleep time and wakefulness after persistent sleep onset at night 1/week 1, month 1, and month 3 in both trials and at most individual time points for subjective time to sleep onset and LPS in each trial. Both doses of suvorexant were generally well tolerated, with <5% of patients discontinuing due to adverse events over 3 months. The results did not suggest the emergence of marked rebound or withdrawal signs or symptoms when suvorexant was discontinued.

CONCLUSIONS

Suvorexant improved sleep onset and maintenance over 3 months of nightly treatment and was generally safe and well tolerated.

Randomized, controlled trial of telcagepant over four migraine attacks

METHODS

This study evaluated the calcitonin gene-related peptide (CGRP) receptor antagonist telcagepant (tablet formulation) for treatment of a migraine attack and across four attacks. Adults with migraine were randomized, double-blind, to telcagepant 140 mg, telcagepant 280 mg, or control treatment sequences to treat four moderate-to-severe migraine attacks. Control patients received placebo for three attacks and telcagepant 140 mg for one attack. Efficacy for the first attack (Attack 1) and consistency of efficacy over multiple attacks were assessed. For an individual patient, consistent efficacy was defined as ≥ 3 successes, and lack of consistent efficacy was defined as ≥ 2 failures, in treatment response. A total of 1677 patients treated ≥ 1 attack and 1263 treated all four attacks.

RESULTS

Based on Attack 1 data, telcagepant 140 mg and 280 mg were significantly (p < .001) more effective than placebo for 2-hour pain freedom, 2-hour pain relief, 2-hour absence of migraine-associated symptoms (phonophobia, photophobia, nausea), and 2-24 hours sustained pain freedom. The percentage of patients with 2-hour pain freedom consistency and 2-hour pain relief consistency was significantly (p < .001) higher for both telcagepant treatment sequences versus control. Adverse events within 48 hours for telcagepant with an incidence ≥ 2% and twice that of placebo were somnolence (placebo = 2.3%, 140 mg = 5.9%, 280 mg = 5.7%) and vomiting (placebo = 1.4%, 140 mg = 1.0%, 280 mg = 2.9%).

CONCLUSION

Telcagepant 140 mg and 280 mg were effective for treatment of a migraine attack and were more consistently effective than control for intermittent treatment of up to four migraine attacks. Telcagepant was generally well tolerated. (Clinicaltrials.gov; NCT00483704).

Efficacy and tolerability of MK-0974 (telcagepant), a new oral antagonist of calcitonin gene-related peptide receptor, compared with zolmitriptan for acute migraine: a randomised, placebo-controlled, parallel-treatment trial

BACKGROUND

Calcitonin gene-related peptide (CGRP) probably has a role in migraine pathophysiology, and antagonism of its receptors might provide treatment without the vasoconstrictor effects of triptans. We aimed to assess the clinical profile of MK-0974 (telcagepant), an orally bioavailable antagonist of CGRP receptor.

METHODS

In a randomised, parallel-treatment, placebo-controlled, double-blind, trial at 81 sites in the Europe and the USA, adults with migraine diagnosed by International Headache Society criteria treated moderate or severe attacks with either oral telcagepant 150 mg or 300 mg, zolmitriptan 5 mg, or placebo. The five co-primary endpoints were pain freedom, pain relief, or absence of photophobia, phonophobia, or nausea at 2 h after treatment. Analysis was by the full analysis set and multiplicity was controlled for with a step-down closed-testing procedure. This trial is registered with ClinicalTrials.gov, number NCT00442936.

FINDINGS

1380 patients were randomly assigned to receive telcagepant 150 mg (n=333) or 300 mg (354), zolmitriptan (345), or placebo (348). Telcagepant 300 mg was more effective than placebo for pain freedom (95 [27%] of 353 patients vs 33 [10%] of 343 [p<0.0001]), pain relief (194 [55%] of 353 vs 95 [28%] of 343 [p<0.0001]), and absences of phonophobia (204 [58%] of 353 vs 126 [37%] of 342 [p<0.0001]), photophobia (180 [51%] of 353 vs 99 [29%] of 342 [p<0.0001]), and nausea (229 [65%] of 352 vs 189 [55%] of 342 [p=0.0061]). Efficacy of telcagepant 300 mg and zolmitriptan 5 mg were much the same, and both were more effective than telcagepant 150 mg. Adverse events were recorded for 31% taking telcagepant 150 mg, 37% taking telcagepant 300 mg, 51% taking zolmitriptan 5 mg, and 32% taking placebo.

INTERPRETATION

Telcagepant 300 mg is effective as an acute treatment for migraine with efficacy comparable to that of zolmitriptan 5 mg, but with fewer associated adverse effects.

FUNDING

Merck Research Laboratories.

Efficient assessment of neuropathic pain drugs in patients with small fiber sensory neuropathies

We sought to develop an enrichment crossover study design that would allow us to efficiently evaluate and compare promising candidate neuropathic pain drugs. We evaluated the efficacy of gabapentin or tramadol vs. active placebo (diphenhydramine) in subjects with biopsy-proven painful idiopathic small fiber neuropathy (SFN) who were self-reported gabapentin responders. Eligible subjects entered two single blind run-in phases. In the first phase (Period A), subjects were treated with single blinded gabapentin at their prestudy dose followed by a second run-in phase (Period B) in which they were treated with diphenhydramine active placebo. Subjects with >or=3 pain and a >or=30% increase in pain intensity in Period B compared to Period A were then randomized to a double-blind three period cross over trial of gabapentin at pre study dosage, tramadol 50mg QID and diphenhydramine 50mgqhs. Of the 59 subjects enrolled, 41 subjects were excluded: Twenty-three had an insufficient rise in pain intensity in Period B; eight had skin biopsies that did not confirm SFN. Eighteen subjects were randomized into the double-blind, crossover phase. There was a significant treatment effect of gabapentin vs. diphenhydramine (p=0.001) and tramadol vs. diphenhydramine (p=0.018) by the before-bed daily pain score averaged over the final 7 days of each treatment period. We conclude that gabapentin and tramadol were effective in the treatment of painful SFN and that this experimental enrichment paradigm is attractive to screen potential neuropathic pain compounds for efficacy in proof-of-concept studies.