A double-blind, randomized, placebo-controlled, single-dose study of the cyclooxygenase-2 inhibitor, GW406381, as a treatment for acute migraine

A randomized study of IV prochlorperazine plus diphenhydramine versus IV hydromorphone for migraine-associated symptoms: A post hoc analysis

OBJECTIVE

We conducted a randomized trial among emergency department patients with migraine to determine the relative impact on migraine-associated symptoms of hydromorphone, an opioid, versus prochlorperazine, an antidopaminergic antiemetic.

METHODS

This was a post hoc analysis of data from a double-blind study registered at http://clinicaltrials.gov (NCT02389829). Patients who met International Classification of Headache Disorders, 3rd edition criteria for migraine without aura or for probable migraine without aura were eligible for participation. Participants received either hydromorphone 1 mg IV or prochlorperazine 10 mg IV plus diphenhydramine 25 mg IV and could receive a second dose of the same medication 1 h later if needed. The outcomes were sustained relief of nausea, photophobia, and phonophobia.

RESULTS

A total of 127 patients were enrolled, of whom 63 received prochlorperazine and 64 received hydromorphone. Of 49 patients in the prochlorperazine arm who reported nausea at baseline, 34 (69.4%) reported complete resolution without relapse versus 15/49 (30.6%) in the hydromorphone arm (absolute risk reduction [ARR] = 38.8%, 95% CI: 20.5%-57.0%, p < 0.001). Of 55 patients in the prochlorperazine arm who reported photophobia at baseline, 23 (41.8%) reported complete resolution without relapse versus 13/62 (20.9%) patients treated with hydromorphone (ARR = 20.8%, 95% CI: 4.3%-37.3%, p = 0.014). Of 56 patients in the prochlorperazine arm who reported phonophobia at baseline, 25 (44.6%) reported complete resolution without relapse versus 16/59 (27.1%) in the hydromorphone arm (ARR = 17.5%, 95% CI: 0.3%-34.8%, p = 0.049). For adverse events, three patients in the prochlorperazine arm reported anxiety or restlessness, and nine patients in the hydromorphone arm reported dizziness or weakness.

CONCLUSIONS

Prochlorperazine plus diphenhydramine is more efficacious than hydromorphone for the treatment of migraine-associated symptoms.

Association of the cyclooxygenase-2 1759A allele with migraine in Chinese Han individuals

Cyclooxygenase-2 (COX-2) is known to be involved in the pathogenesis of migraine, and some polymorphisms are known to affect the expression of COX-2. This retrospective case-control study aimed to explore the associations between the -765 G>C (rs20417), -1759 G>A (rs3218625), and -8473 C>T (rs5275) COX-2 polymorphisms and migraine in Chinese Han individuals. One hundred and ten unrelated Han Chinese patients with migraine and 108 healthy controls were recruited between 03/2014 and 08/2016 at the First Affiliated Hospital of Nanjing Medical University and the First People's Hospital of Lianyungang City. The genotypes of all polymorphisms in controls followed the Hardy-Weinberg equilibrium (P = 0.215, P = 0.884, and P = 0.689). There were differences in the genotype and allele distributions of the COX-2-1759G>A (Gly587Arg) polymorphism between the migraine and control groups (P = 0.038 and P = 0.040, respectively). Compared with the COX-2-1759AG genotype, GG genotype carriers had an increased risk of migraine (odds ratio (OR) = 8.720, 95% confidence interval (CI): 1.072-70.960, P = 0.038). The frequency of the COX-2-1759A allele in patients with migraine was significantly lower than the controls (OR = 0.119, 95%CI: 0.015-0.957, P = 0.040). Adjusted age and sex, a statistical difference was found in the dominant model of COX-2-1759 G>A (OR = 0.118, 95% CI 0.014 to 0.962, P = 0.046). No significant difference was detected regarding the -765G>C and -8473T>C polymorphisms between the two groups. The COX-2 1759A allele might be involved in the development of migraine in Chinese Han individuals, but this will have to be confirmed in large-scale studies.

Comparative tolerability of treatments for acute migraine: A network meta-analysis

Introduction

Migraine headache is a neurological disorder whose attacks are associated with nausea, vomiting, photophobia and phonophobia. Treatments for migraine aim to either prevent attacks before they have started or relieve attacks (abort) after onset of symptoms and range from complementary therapies to pharmacological interventions. A number of treatment-related adverse events such as somnolence, fatigue, and chest discomfort have previously been reported in association with triptans. The comparative tolerability of available agents for the abortive treatment of migraine attacks has not yet been systematically reviewed and quantified.

Methods

We performed a systematic literature review and Bayesian network meta-analysis for comparative tolerability of treatments for migraine. The literature search targeted all randomized controlled trials evaluating oral abortive treatments for acute migraine over a range of available doses in adults. The primary outcomes of interest were any adverse event, treatment-related adverse events, and serious adverse events. Secondary outcomes were fatigue, dizziness, chest discomfort, somnolence, nausea, and vomiting.

Results

Our search yielded 141 trials covering 15 distinct treatments. Of the triptans, sumatriptan, eletriptan, rizatriptan, zolmitriptan, and the combination treatment of sumatriptan and naproxen were associated with a statistically significant increase in odds of any adverse event or a treatment-related adverse event occurring compared with placebo. Of the non-triptans, only acetaminophen was associated with a statistically significant increase in odds of an adverse event occurring when compared with placebo. Overall, triptans were not associated with increased odds of serious adverse events occurring and the same was the case for non-triptans. For the secondary outcomes, with the exception of vomiting, all triptans except for almotriptan and frovatriptan were significantly associated with increased risk for all outcomes. Almotriptan was significantly associated with an increased risk of vomiting, whereas all other triptans yielded non-significant lower odds compared with placebo. Generally, the non-triptans were not associated with decreased tolerability for the secondary outcomes.

Discussion

In summary, triptans were associated with higher odds of any adverse event or a treatment-related adverse event occurring when compared to placebo and non-triptans. Non-significant results for non-triptans indicate that these treatments are comparable with one another and placebo regarding tolerability outcomes.

Oral nonsteroidal anti-inflammatory drugs for neuropathic pain

BACKGROUND

Although often considered to be lacking adequate evidence, nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in the management of neuropathic pain. Previous surveys found 18% to 47% of affected people reported using NSAIDs specifically for their neuropathic pain, although possibly not in the United Kingdom (UK).

OBJECTIVES

To assess the analgesic efficacy of oral NSAIDs for chronic neuropathic pain in adults, when compared to placebo or another active intervention, and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and EMBASE from inception to 29 May 2015, together with reference lists of retrieved papers and reviews, and an online trials registry.

SELECTION CRITERIA

We included randomised, double-blind studies of two weeks duration or longer, comparing any oral NSAID with placebo or another active treatment in chronic neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality. We did not carry out any pooled analysis.

MAIN RESULTS

We included two studies involving 251 participants with chronic low back pain with a neuropathic component or postherpetic neuralgia; 209 of these participants were involved in a study of an experimental NSAID not used in clinical practice, and of the remaining 42, only 16 had neuropathic pain. This represented only third tier evidence, and was of very low quality. There was no indication of any significant pain reduction with NSAIDs. Adverse event rates were low, with insufficient events for any analysis.

AUTHORS' CONCLUSIONS

There is no evidence to support or refute the use of oral NSAIDs to treat neuropathic pain conditions.

Naproxen with or without an antiemetic for acute migraine headaches in adults

BACKGROUND

Migraine is a common, disabling condition and a burden for the individual, health services, and society. Many sufferers choose not to, or are unable to, seek professional help and rely on over-the-counter analgesics. Naproxen is a non-steroidal anti-inflammatory drug (NSAID); its efficacy in acute migraine has not been established by systematic reviews. Co-therapy with an antiemetic should help to reduce the nausea and vomiting commonly associated with migraine headaches.

OBJECTIVES

To determine the efficacy and tolerability of naproxen, alone or in combination with an antiemetic, compared with placebo and other active interventions in the treatment of acute migraine headaches in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library, MEDLINE, EMBASE, and the Oxford Pain Relief Database, together with two online databases (www.gsk-clinicalstudyregister.com and www.clinicaltrials.gov) and reference lists, for studies to 22 May 2013.

SELECTION CRITERIA

We included randomised, double-blind, placebo- or active-controlled studies, with at least 10 participants per treatment arm, using naproxen alone or with an antiemetic to treat a migraine headache episode.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We used numbers of participants achieving each outcome to calculate risk ratios and numbers needed to treat (NNT) or harm (NNH) compared with placebo or a different active treatment.

MAIN RESULTS

We included six studies using naproxen 275 mg, 500 mg, or 825 mg to treat attacks of moderate or severe pain intensity. Overall, 1241 participants took naproxen (275 mg to 825 mg), 229 took sumatriptan 50 mg, 173 took naratriptan 2.5 mg, and 1092 took placebo. No studies combined naproxen with an antiemetic. Studies using naproxen 275 mg provided no useable data for analysis.Naproxen (500 mg and 825 mg) was better than placebo for pain-free response and headache relief. At two hours, the NNT for pain-free response was 11 (17% response with naproxen, 8% with placebo; risk ratio 2.0 (95% CI 1.6 to 2.6), moderate quality) and for headache relief was 6.0 (45% response with naproxen, 29% with placebo; risk ratio 1.6 (1.4 to 1.8), moderate quality). The NNT for sustained pain-free response during the 24 hours post dose was 19 (12% response with naproxen, 6.7% with placebo), and for sustained headache relief during the 24 hours post dose was 8.3 (30% response with naproxen, 18% with placebo). Analysing only the lower dose of 500 mg of naproxen did not significantly change the results. Adverse events, which were mostly mild or moderate in severity and rarely led to withdrawal, were more common with naproxen than with placebo when the 500 mg and 825 mg doses were considered together, but not when the 500 mg dose was analysed alone.There were insufficient data for analysis of naproxen compared with sumatriptan, and no data suitable for analysis of naproxen compared with naratriptan.

AUTHORS' CONCLUSIONS

Naproxen is statistically superior to placebo in the treatment of acute migraine, but the NNT of 11 for pain-free response at two hours suggests that it is not a clinically useful treatment. Cochrane reviews examining other commonly used analgesics for acute migraine have reported better (lower) NNT results for the same outcome. Naproxen is not clinically useful as a stand-alone analgesic in acute migraine, as it is effective in fewer than 2 people in 10.

Predictive validity of behavioural animal models for chronic pain

Rodent models of chronic pain may elucidate pathophysiological mechanisms and identify potential drug targets, but whether they predict clinical efficacy of novel compounds is controversial. Several potential analgesics have failed in clinical trials, in spite of strong animal modelling support for efficacy, but there are also examples of successful modelling. Significant differences in how methods are implemented and results are reported means that a literature-based comparison between preclinical data and clinical trials will not reveal whether a particular model is generally predictive. Limited reports on negative outcomes prevents reliable estimate of specificity of any model. Animal models tend to be validated with standard analgesics and may be biased towards tractable pain mechanisms. But preclinical publications rarely contain drug exposure data, and drugs are usually given in high doses and as a single administration, which may lead to drug distribution and exposure deviating significantly from clinical conditions. The greatest challenge for predictive modelling is, however, the heterogeneity of the target patient populations, in terms of both symptoms and pharmacology, probably reflecting differences in pathophysiology. In well-controlled clinical trials, a majority of patients shows less than 50% reduction in pain. A model that responds well to current analgesics should therefore predict efficacy only in a subset of patients within a diagnostic group. It follows that successful translation requires several models for each indication, reflecting critical pathophysiological processes, combined with data linking exposure levels with effect on target.

Are the current IHS guidelines for migraine drug trials being followed?

In 2000, the Clinical Trials Subcommittee of the International Headache Society (IHS) published the second edition of its guidelines for controlled trials of drugs in migraine. The purpose of this publication was to improve the quality of such trials by increasing the awareness amongst investigators of the methodological issues specific to this particular illness. Until now the adherence to these guidelines has not been systematically assessed. We reviewed all published controlled trials of drugs in migraine from 2002 to 2008. Eligible trials were scored for compliance with the IHS guidelines by using grading scales based on the most essential recommendations of the guidelines. The primary efficacy measure of each trial was also recorded. A total of 145 trials of acute treatment and 52 trials of prophylactic treatment were eligible for review. Of the randomized, double-blind trials, acute trials scored an average of 4.7 out of 7 while prophylactic trials scored an average of 5.6 out of 9 for compliance. Thirty-one percent of acute trials and 72% of prophylactic trials used the recommended primary efficacy measure. Fourteen percent of the reviewed trials were either not randomized or not double-blinded. Adherence to international guidelines like these of IHS is important to ensure that only high-quality trials are performed, and to provide the consensus that is required for meta analyses. The primary efficacy measure for trials of acute treatment should be “pain free” and not “headache relief”. Open-label or non-randomized trials generally have no place in the study of migraine drugs.

A randomized, controlled, dose-ranging study investigating single doses of GW406381, naproxen sodium, or placebo in patients with acute pain after third molar tooth extraction

OBJECTIVES

To evaluate the efficacy and tolerability of 4 doses of GW406381, a cyclooxygenase-2 inhibitor, compared with placebo in a standard model of acute inflammatory pain.

METHODS

This randomized, double-blind, placebo-controlled, single-center study compared single doses of GW406381 (10 to 70 mg) or naproxen sodium 550 mg with placebo in patients after extraction of 2 or more partially bony impacted third molar teeth. A total of 300 patients were randomized (50 per group). The primary efficacy variable was the pain relief intensity difference score at each time point, which was calculated as the sum of the pain intensity difference and pain relief categorical scores at each time point. Each treatment was compared with placebo at each time point using an ordered hierarchical approach with closed testing procedures and last observation carried forward imputation methods.

RESULTS

Pain relief intensity differences from placebo were statistically significant beginning at 1.5 hours postdosing for GW406381 70 and 50 mg and at 2-hour postdosing for GW406381 25 and 10 mg. The median time to onset of analgesia was 71 minutes for GW406381 50 mg, 72 minutes for GW406381 70 mg, and 36 minutes for naproxen. The median duration of analgesia was 5.9 hours for GW406381 50 mg, 7.9 hours for GW406391 70 mg, and 11.3 hours for naproxen. All treatments were well tolerated.

DISCUSSION

GW406381 50 and 70 mg demonstrated clinically meaningful analgesia in this acute pain setting, although the onset of analgesia was greater than 1 hour.

Migraine, allodynia, and implications for treatment

Allodynia--perception of pain from non-noxious stimuli--is a common clinical feature in various pain syndromes. The significance for migraine has increasingly been recognized and the pathophysiology has been investigated in detail. Allodynia is a marker for sensitization of central trigeminal neurons. Intensity and persistence of allodynic symptoms are a function of duration of migraine attacks, frequency of attacks, and migraine history. It has been hypothesized that treatment success with triptans may be severely impaired in the presence of allodynia. However, randomized controlled trials did not confirm that. Treatment with cyclooxygenase inhibitors and dihydroergotamine does not seem to be limited by allodynia; these medications may be able to reverse allodynia. Data on the new class of calcitonin-gene related-peptide antagonists are not yet available. Additional and more refined randomized controlled trials, focusing on methodological issues pertaining to the determination of allodynia, are warranted to resolve the true relationship between allodynia and treatment response. Regardless--based on available randomized controlled trials--the recommendation prevails to initiate abortive treatment as soon as possible after attack onset when pain is still mild.