Comparison of the efficacy of zolmitriptan and sumatriptan: issues in migraine trial design

Comparison between metamizole and triptans for migraine treatment: a systematic review and network meta-analysis

Objective The aim of this systematic review was to evaluate the efficacy of metamizole and triptans for the treatment of migraine. MethodsRandomized controlled trials including people who received metamizole or triptan by multiple routes of administration and at all doses as treatment compared to subjects who received another treatment or placebo were included in the systematic review. The primary outcomes were freedom from pain at 2 hours; pain relief at 2 hours; sustained headache response at 24 hours; sustained freedom from pain at 24 hours. The statistical analysis of all interventions of interest were based on random effect models compared through a network meta-analysis. Results 209 studies meeting the inclusion and exclusion criteria were analyzed. Of these, 130 had data that could be analyzed statistically. Only 3.0% provided enough information and were judged to have a low overall risk of bias for all categories evaluated; approximately 50% of the studies presented a low risk of selection bias. More than 75% of the studies presented a low risk of performance bias, and around 75% showed a low risk of detection and attrition bias. ConclusionThere is no evidence of a difference between dipyrone and any triptan for pain freedom after 2 hours of medication. Our study suggests that metamizole may be equally effective as triptans in acute migraine treatment.

Placebo response with subcutaneous injections in calcitonin gene-related peptide receptor monoclonal antibody migraine preventative trials – A systematic review and meta-analysis

Background:

The majority of CGRP monoclonal antibodies for migraine prevention are administered subcutaneously. Therefore, we attempted to calculate the pooled placebo response with subcutaneous placebo injections in this systematic review and meta-analysis.

Methods:

We identified 16 randomized controlled trials that met our inclusion and exclusion criteria through a comprehensive search in five electronic databases (PubMed Central, EMBASE, MEDLINE, Cochrane library and clinicaltrials.gov ). The risk of bias was assessed for all included studies. Random effects model was used to calculate pooled mean monthly migraine days and 50% response rates.

Results:

A total of 4240 subjects were included from 16 studies in this meta-analysis. The pooled mean monthly migraine day reduction with subcutaneous placebo injections was 2.15 (95% CI: 1.60–2.69). The pooled proportion of patients achieving a 50% reduction in mean monthly headache days was 26% (95% CI: 20%–31%). Placebo response accounted for more than 50% of therapeutic gain in our study.

Conclusion:

A substantial placebo response was noted with subcutaneous injections in migraine CGRP monoclonal antibody clinical trials. This meta-analysis may serve as a reference point to calculate sample size in clinical trials using subcutaneous interventions for migraine prevention. We registered our study at PROSPERO (CRD42020185300).

The effectiveness and value of novel acute treatments for migraine

DISCLOSURES: Funding for this summary was contributed by Arnold Ventures, California Health Care Foundation, Harvard Pilgrim Health Care, and Kaiser Foundation Health Plan to the Institute for Clinical and Economic Review (ICER), an independent organization that evaluates the evidence on the value of health care interventions. ICER's annual policy summit is supported by dues from Aetna, America's Health Insurance Plans, Anthem, Allergan, Alnylam, AstraZeneca, Biogen, Blue Shield of CA, Boehringer-Ingelheim, Cambia Health Services, CVS, Editas, Express Scripts, Genentech/Roche, GlaxoSmithKline, Harvard Pilgrim, Health Care Service Corporation, HealthFirst, Health Partners, Johnson & Johnson (Janssen), Kaiser Permanente, LEO Pharma, Mallinckrodt, Merck, Novartis, National Pharmaceutical Council, Pfizer, Premera, Prime Therapeutics, Regeneron, Sanofi, Spark Therapeutics, and United Healthcare. Agboola, Borrelli, Rind, and Pearson are employed by ICER. Touchette, through the University of Illinois at Chicago, received funding from ICER for development of the economic model described in this publication. Atlas has nothing to disclose.

Use of Most Bothersome Symptom as a Coprimary Endpoint in Migraine Clinical Trials: A Post-Hoc Analysis of the Pivotal ZOTRIP Randomized, Controlled Trial

Objective

To better understand the utility of using pain freedom and most bothersome headache‐associated symptom (MBS) freedom as co‐primary endpoints in clinical trials of acute migraine interventions.

Background

Adhesive dermally applied microarray (ADAM) is an investigational system for intracutaneous drug administration. The recently completed pivotal Phase 2b/3 study (ZOTRIP), evaluating ADAM zolmitriptan for the treatment of acute moderate to severe migraine, was one of the first large studies to incorporate MBS freedom and pain freedom as co‐primary endpoints per recently issued guidance by the US Food and Drug Administration. In this trial, the proportion of patients treated with ADAM zolmitriptan 3.8 mg, who were pain‐free and MBS‐free at 2 hours post‐dose, was significantly higher than for placebo.

Methods

We undertook a post‐hoc analysis of data from the ZOTRIP trial to examine how the outcomes from this trial compare to what might have been achieved using the conventional co‐primary endpoints of pain relief, nausea, photophobia, and phonophobia.

Results

Of the 159 patients treated with ADAM zolmitriptan 3.8 mg or placebo, prospectively designated MBS were photophobia (n = 79), phonophobia (n = 43), and nausea (n = 37). Two‐hour pain free rates in those with photophobia as the MBS were 36% for ADAM zolmitriptan 3.8 mg and 14% for placebo (P = .02). Corresponding rates for those with phonophobia as the MBS were 14% and 41% (P = .05). For those whose MBS was nausea, corresponding values were 56% and 16%, respectively (P = .01). Two‐hour freedom from the MBS for active drug vs placebo were 67% vs 35% (P < .01) for photophobia, 55% vs 43% (P = .45) for phonophobia, and 89% vs 58% for nausea (P = .04). MBS freedom but not pain freedom was achieved in 28%. Only 1 patient (1%) achieved pain freedom, but not MBS freedom. The proportion with both pain and MBS freedom was highest (56%) among those whose MBS was nausea.

Conclusion

In this study, the use of MBS was feasible and seemed to compare favorably to the previously required 4 co‐primary endpoints.

Randomized, double-blind, placebo-controlled, parallel-group, multi-center study of the safety and efficacy of ADAM zolmitriptan for the acute treatment of migraine

Objective To determine the efficacy, tolerability, and safety of ascending doses of Adhesive Dermally-Applied Microarray (ADAM) zolmitriptan versus placebo for acute migraine treatment. Background ADAM is a novel patient-administered system for intracutaneous drug administration. In a phase 1 pharmacokinetic study, zolmitriptan administered using ADAM had much faster absorption than oral administration with higher exposure in the first two hours. Methods This was a multicenter, randomized, double-blind, placebo-controlled, parallel-group Phase 2b/3 study evaluating ADAM zolmitriptan 1 mg, 1.9 mg, and 3.8 mg versus placebo. Co-primary endpoints were pain freedom and freedom from most bothersome other migraine-associated symptom 2 hours post-dose. Results Of patients treated with ADAM zolmitriptan 3.8 mg or placebo, 41.5% and 14.2%, respectively were pain-free 2 hours post-dose ( p = 0.0001) and 68.3% and 42.9% were free from their most bothersome other symptom ( p = 0.0009). Due to the fixed sequential testing methodology, formal statistical significance was not established for secondary endpoints. However, the proportion of patients who were photophobia-free, phonophobia-free, and nausea-free at 2 hours post-dose was higher in the ADAM zolmitriptan 3.8 mg group compared with placebo, as were the percentages of patients who were pain-free, and who experienced pain relief up to 48 hours post-dose. Systemic adverse events were consistent with previous triptan trials, and included dizziness, paresthesia, muscle tightness, and nausea, all of which occurred in < 5% of patients in any group. Application site reactions were generally mild and resolved within 48 hours, although erythema and bruising persisted for longer periods in some patients. Conclusion ADAM zolmitriptan 3.8 mg provides effective relief of migraine headache and associated most bothersome symptoms compared with placebo, and is well-tolerated. ClinicalTrials.gov NCT02745392.

Network meta-analysis of migraine disorder treatment by NSAIDs and triptans

Background

Migraine is a neurological disorder resulting in large socioeconomic burden. This network meta-analysis (NMA) is designed to compare the relative efficacy and tolerability of non-steroidal anti-inflammatory agents (NSAIDs) and triptans.

Methods

We conducted systematic searches in database PubMed and Embase. Treatment effectiveness was compared by synthesizing direct and indirect evidences using NMA. The surface under curve ranking area (SUCRA) was created to rank those interventions.

Results

Eletriptan and rizatriptan are superior to sumatriptan, zolmitriptan, almotriptan, ibuprofen and aspirin with respect to pain-relief. When analyzing 2 h-nausea-absence, rizatriptan has a better efficacy than sumatriptan, while other treatments indicate no distinctive difference compared with placebo. Furthermore, sumatriptan demonstrates a higher incidence of all-adverse-event compared with diclofenac-potassium, ibuprofen and almotriptan.

Conclusion

This study suggests that eletriptan may be the most suitable therapy for migraine from a comprehensive point of view. In the meantime ibuprofen may also be a good choice for its excellent tolerability. Multi-component medication also attracts attention and may be a promising avenue for the next generation of migraine treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s10194-016-0703-0) contains supplementary material, which is available to authorized users.

Placebo Effects in Oral Triptan Trials: the Scientific and Ethical Rationale for Continued use of Placebo Controls

The aim of this study was to determine the characteristics of placebo effects in acute migraine treatment trials of triptans performed over 12 years and assess whether the use of placebo controls in trials of acute migraine treatment remains ethically and scientifically appropriate. We conducted a search for all controlled trials published in English between January 1991 and April 2002 in which adult subjects with migraine were randomly assigned to receive an oral triptan or placebo for the acute treatment of a migraine attack. Thirty-one trials met our criteria for inclusion. Placebo results for each study and pooled placebo results were calculated for the endpoints of headache response, pain-free response and adverse events. Heterogeneity was assessed using the Q statistic, and meta-regression using prespecified covariates was performed to investigate heterogeneity. The study results show a significant degree of heterogeneity. Efforts to explain heterogeneity with available data were not successful, with the exception of adverse event rates to placebo, for which study location (Europe vs. North America) partially explained differences in study results. AE rates were lower in European studies than in North American studies. Across all studies, the mean proportion of subjects who experienced a treatment response at two hours to placebo was 28.48 + 8.73% (range 17-50%). The mean proportion of subjects who experienced an adverse event to placebo was 23.40 + 14.05% (range 4.86-74%). The mean proportion of subjects who experienced a pain-free response to placebo at two hours was 6.08 + 4.43% (range 5-17%). Results of studies allowing use of prophylaxis did not differ significantly from those that did not allow prophylaxis. Placebo effects appear to be enhanced in studies involving children and adolescents. In contrast to an earlier, smaller review, our results do not suggest that randomization ratios influence placebo rates. We conclude that placebo effects in published trials of acute migraine medications are highly variable and often substantial. This variability in placebo response means that active control equivalence trials or the use of historical controls will not provide adequate proof of the safety or efficacy of new drugs, and will not differentiate between drugs that are active vs. placebo but of unknown efficacy relative to each other. The potential for approval of ineffective drugs, inability to compare results of studies performed in different locations, and poor characterization of the tolerability and safety profiles of new drugs represent a greater danger to migraineurs than does the limited-duration use of placebo in carefully monitored clinical trials of consenting subjects. These observations support the view that the inclusion of a placebo group remains of major scientific and ethical importance in trials of migraine medications.

Triptans and Chest Symptoms: The Role of Pulmonary Vasoconstriction

Triptans are effective and well tolerated in the treatment of acute migraine. Chest symptoms are a common adverse effect unrelated to coronary vasoconstriction in most patients. Although the aetiology of chest symptoms remains to be fully defined, pulmonary vasoconstriction is a possible underlying mechanism. Preclinical studies of isolated human blood vessels were used to identify the cerebral selectivity of triptans and ascertain if selectivity vs the pulmonary vasculature predicts a lower rate of chest symptoms. Controlled clinical trials and post-marketing surveillance studies were reviewed to document the incidence of chest symptoms after triptan therapy. In clinical trials, the incidence of chest symptoms at usual therapeutic doses ranged from 1 to 4% depending on the triptan and study design, whereas in post-marketing surveillance studies, up to 41% of patients specifically asked about chest symptoms reported them. A comparative clinical trial showed that almotriptan was associated with lower incidence of chest symptoms than sumatriptan (0.3 vs 2.2%). The intrinsic activity of almotriptan, a second-generation triptan, on human pulmonary arteries and veins was lower than that of sumatriptan. Pre-clinical studies of isolated pulmonary blood vessels may predict the clinical likelihood of chest symptoms; however, additional comparisons are needed.

Patient Preference in Clinical Trials for Headache Medication: The Patient's View

From a clinical point of view, the subjective preference of the patient regarding headache medication is imperative. Consequently, a new trial design for headache medication, the so-called patient preference trial, has been vividly discussed. However, some critical questions have been raised concerning preference trials, such as whether placebos should be used, the necessity of blinding, and how to assess the data if a patient does not prefer medication A over B. As patient preference is the topic, we passed these questions on to headache patients using a questionnaire, which was handed out to 1112 headache patients. Out of 612, 486 returned questionnaires were correctly completed and analysed. Complete pain relief was the most important factor for 61% of patients to qualify a therapy effective. This is in contrast to the literature, where rapid speed of onset of the drug is discussed as the most important factor for migraineurs. Regarding the study design, 80% of the patients want to decide the time-point of taking acute medication themselves. About 60% of the patients would participate in placebo-controlled clinical trials and agree that studies should be blinded. If patients had to decide between two equally effective drugs, most would vote for the drug which is available in different application forms. Furthermore, we used the same questionnaire to ask headache specialists with expertise in performing headache studies the same questions. This was mailed to and completed by 22 experts in Germany. In this article, we discuss the patient preference compared with the expert preference regarding clinic trials and drug therapy.

OnabotulinumtoxinA for chronic migraine: a critical appraisal

Chronic migraine (CM) is a severe disabling condition with a few available evidence-based management options. OnabotulinumtoxinA (onaBoNTA) is approved for use in a number of disorders. Its benefits and potential use in migraine were observed incidentally while treating patients cosmetically for wrinkles. The mechanism of action of onaBoNTA in CM is not fully understood, but there is evidence that this involves axonal transport via sensory fibers. The Phase III REsearch Evaluating Migraine Prophylaxis Therapy trials have established the efficacy as well as the long-term safety and tolerability of onaBoNTA in CM. This review will discuss the evidence behind its use in this setting.

AVP-825 breath-powered intranasal delivery system containing 22 mg sumatriptan powder vs 100 mg oral sumatriptan in the acute treatment of migraines (The COMPASS study): a comparative randomized clinical trial across multiple attacks

OBJECTIVE

The objective of this study was to compare the efficacy, tolerability, and safety of AVP-825, an investigational bi-directional breath-powered intranasal delivery system containing low-dose (22 mg) sumatriptan powder, vs 100 mg oral sumatriptan for acute treatment of migraine in a double-dummy, randomized comparative efficacy clinical trial allowing treatment across multiple migraine attacks.

BACKGROUND

In phases 2 and 3, randomized, placebo-controlled trials, AVP-825 provided early and sustained relief of moderate or severe migraine headache in adults, with a low incidence of triptan-related adverse effects.

METHODS

This was a randomized, active-comparator, double-dummy, cross-over, multi-attack study (COMPASS; NCT01667679) with two ≤12-week double-blind periods. Subjects experiencing 2-8 migraines/month in the past year were randomized 1:1 using computer-generated sequences to AVP-825 plus oral placebo tablet or an identical placebo delivery system plus 100 mg oral sumatriptan tablet for the first period; patients switched treatment for the second period in this controlled comparative design. Subjects treated ≤5 qualifying migraines per period within 1 hour of onset, even if pain was mild. The primary end-point was the mean value of the summed pain intensity differences through 30 minutes post-dose (SPID-30) using Headache Severity scores. Secondary outcomes included pain relief, pain freedom, pain reduction, consistency of response across multiple migraines, migraine-associated symptoms, and atypical sensations. Safety was also assessed.

RESULTS

A total of 275 adults were randomized, 174 (63.3%) completed the study (ie, completed the second treatment period), and 185 (67.3%) treated at least one migraine in both periods (1531 migraines assessed). There was significantly greater reduction in migraine pain intensity with AVP-825 vs oral sumatriptan in the first 30 minutes post-dose (least squares mean SPID-30 = 10.80 vs 7.41, adjusted mean difference 3.39 [95% confidence interval 1.76, 5.01]; P < .001). At each time point measured between 15 and 90 minutes, significantly greater rates of pain relief and pain freedom occurred with AVP-825 treatment compared with oral sumatriptan. At 2 hours, rates of pain relief and pain freedom became comparable; rates of sustained pain relief and sustained pain freedom from 2 to 48 hours remained comparable. Nasal discomfort and abnormal taste were more common with AVP-825 vs oral sumatriptan (16% vs 1% and 26% vs 4%, respectively), but ∼90% were mild, leading to only one discontinuation. Atypical sensation rates were significantly lower with AVP-825 than with conventional higher dose 100 mg oral sumatriptan.

CONCLUSIONS

AVP-825 (containing 22 mg sumatriptan nasal powder) provided statistically significantly greater reduction of migraine pain intensity over the first 30 minutes following treatment, and greater rates of pain relief and pain freedom within 15 minutes, compared with 100 mg oral sumatriptan. Sustained pain relief and pain freedom through 24 and 48 hours was achieved in a similar percentage of attacks for both treatments, despite substantially lower total systemic drug exposure with AVP-825. Treatment was well tolerated, with statistically significantly fewer atypical sensations with AVP-825.

Zolmitriptan for acute migraine attacks in adults

BACKGROUND

Migraine is a common, disabling condition and a burden for the individual, health services, and society. Zolmitriptan is an abortive medication for migraine attacks, belonging to the triptan family. These medicines work in a different way to analgesics such as paracetamol and ibuprofen.

OBJECTIVES

To determine the efficacy and tolerability of zolmitriptan compared to placebo and other active interventions in the treatment of acute migraine attacks in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and the Oxford Pain Relief Database, together with three online databases (www.astrazenecaclinicaltrials.com, www.clinicaltrials.gov, and apps.who.int/trialsearch) for studies to 12 March 2014. We also searched the reference lists of included studies and relevant reviews.

SELECTION CRITERIA

We included randomised, double-blind, placebo- or active-controlled studies, with at least 10 participants per treatment arm, using zolmitriptan 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 for an additional beneficial effect (NNT) or harmful effect (NNH) compared with placebo or a different active treatment.

MAIN RESULTS

Twenty-five studies (20,162 participants) compared zolmitriptan with placebo or an active comparator. The evidence from placebo-controlled studies was of high quality for all outcomes except 24 hour outcomes and serious adverse events where only limited data were available. The majority of included studies were at a low risk of performance, detection and attrition biases, but did not adequately describe methods of randomisation and concealment.Most of the data were for the 2.5 mg and 5 mg doses compared with placebo, for treatment of moderate to severe pain. For all efficacy outcomes, zolmitriptan surpassed placebo. For oral zolmitriptan 2.5 mg versus placebo, the NNTs were 5.0, 3.2, 7.7, and 4.1 for pain-free at two hours, headache relief at two hours, sustained pain-free during the 24 hours postdose, and sustained headache relief during the 24 hours postdose, respectively. Results for the oral 5 mg dose were similar to the 2.5 mg dose, while zolmitriptan 10 mg was significantly more effective than 5 mg for pain-free and headache relief at two hours. For headache relief at one and two hours and sustained headache relief during the 24 hours postdose, but not pain-free at two hours, zolmitriptan 5 mg nasal spray was significantly more effective than the 5 mg oral tablet.For the most part, adverse events were transient and mild and were more common with zolmitriptan than placebo, with a clear dose response relationship (1 mg to 10 mg).High quality evidence from two studies showed that oral zolmitriptan 2.5 mg and 5 mg provided headache relief at two hours to the same proportion of people as oral sumatriptan 50 mg (66%, 67%, and 68% respectively), although not necessarily the same individuals. There was no significant difference in numbers experiencing adverse events. Single studies reported on other active treatment comparisons but are not described further because of the small amount of data.

AUTHORS' CONCLUSIONS

Zolmitriptan is effective as an abortive treatment for migraine attacks for some people, but is associated with increased adverse events compared to placebo. Zolmitriptan 2.5 mg and 5 mg benefited the same proportion of people as sumatriptan 50 mg, although not necessarily the same individuals, for headache relief at two hours.

Zolmitriptan (Zomig®)

New triptans are being released in rapid succession with each addition demonstrating some specific pharmacokinetic properties, which may be translated into clinical advantages. Zolmitriptan (Zomig) offers a range of alternatives to migraine sufferers. The conventional tablet is consistently effective across a wide range of migraine subtypes. The orally disintegrating tablet offers an effective option for those migraineurs who are nauseated or need to take their medication earlier in the course of their migraine. Since it can be taken without fluid, the orally disintegrating tablet may be consistently used early in the migraine attack when the pain is still mild. The nasal spray aggregates all the benefits of the oral formulations and has a faster onset of action. The 5-mg dose of all three forms of zolmitriptan offers additional benefits over the 2.5-mg dose at early time points. The physician can now choose the optimum route of delivery of zolmitriptan to stop the headache, increase the likelihood of reducing disability and restore the patient to complete functionality.

Sumatriptan: a review of its pharmacokinetics, pharmacodynamics and efficacy in the acute treatment of migraine

INTRODUCTION

Sumatriptan was developed more than 20 years ago as a 5-HT1B/1D receptor agonist, the first drug in a new class of specific anti-migraine drugs, the triptans. A large amount of information and experience has been gained from the clinical trials undertaken as well the various formulations of sumatriptan used over this period of time.

AREAS COVERED

This evaluation specifically reviews the pharmacokinetics, pharmacodynamics, clinical efficacy, and safety of different formulations and dosages of sumatriptan used for the acute treatment of migraines. Special clinical trials of the timing of dosage and sumatriptan in combination with other triptans as well as non-triptan drugs are also included.

EXPERT OPINION

Oral sumatriptan is effective, but not in a convincing majority (60%) of patients in clinical trials. Sumatriptan has failed to show superiority over more standard and cheaper treatment such as aspirin or aspirin plus metoclopramide. In addition, migraine patients want to quickly become pain free, and to remain pain free, but oral sumatriptan at 100 mg managed to keep patients pain free for 24 h is only 20% of cases. Even though sumatriptan has been a major step forward in providing a new specific therapy for the treatment of migraines, there are still are limitations in its use. There is still an unmet need to develop new non-triptan, anti-migraine drugs which act as effective treatment for those who suffer with migraines.

Sumatriptan (oral route of administration) for acute migraine attacks in adults

BACKGROUND

Migraine is a highly disabling condition for the individual and also has wide-reaching implications for society, healthcare services, and the economy. Sumatriptan is an abortive medication for migraine attacks, belonging to the triptan family.

OBJECTIVES

To determine the efficacy and tolerability of oral sumatriptan compared to placebo and other active interventions in the treatment of acute migraine attacks in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, online databases, and reference lists for studies through 13 October 2011.

SELECTION CRITERIA

We included randomised, double-blind, placebo- and/or active-controlled studies using oral sumatriptan to treat a migraine headache episode, with at least 10 participants per treatment arm.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

Sixty-one studies (37,250 participants) compared oral sumatriptan with placebo or an active comparator. Most of the data were for the 50 mg and 100 mg doses. Sumatriptan surpassed placebo for all efficacy outcomes. For sumatriptan 50 mg versus placebo the NNTs were 6.1, 7.5, and 4.0 for pain-free at two hours and headache relief at one and two hours, respectively. NNTs for sustained pain-free and sustained headache relief during the 24 hours postdose were 9.5 and 6.0, respectively. For sumatriptan 100 mg versus placebo the NNTs were 4.7, 6.8, 3.5, 6.5, and 5.2, respectively, for the same outcomes. Results for the 25 mg dose were similar to the 50 mg dose, while sumatriptan 100 mg was significantly better than 50 mg for pain-free and headache relief at two hours, and for sustained pain-free during 24 hours. Treating early, during the mild pain phase, gave significantly better NNTs for pain-free at two hours and sustained pain-free during 24 hours than did treating established attacks with moderate or severe pain intensity.Relief of associated symptoms, including nausea, photophobia, and phonophobia, was greater with sumatriptan than with placebo, and use of rescue medication was lower with sumatriptan than with placebo. For the most part, adverse events were transient and mild and were more common with the sumatriptan than with placebo, with a clear dose response relationship (25 mg to 100 mg).Sumatriptan was compared directly with a number of active treatments, including other triptans, paracetamol (acetaminophen), acetylsalicylic acid, non-steroidal anti-inflammatory drugs (NSAIDs), and ergotamine combinations.

AUTHORS' CONCLUSIONS

Oral sumatriptan is effective as an abortive treatment for migraine attacks, relieving pain, nausea, photophobia, phonophobia, and functional disability, but is associated with increased adverse events.

WITHDRAWN: Oral sumatriptan for acute migraine

BACKGROUND

Migraine is a common neurovascular disorder characterized by recurrent episodes of disabling headache, autonomic nervous system dysfunction, and, in some patients, neurological aura symptoms. Sumatriptan is one of a class of selective serotonin 5-hydroxytryptamine (5-HT1B/1D) agonists (triptans) thought to relieve migraine attacks by several mechanisms, including cranial vasoconstriction and peripheral and central neural inhibition.

OBJECTIVES

To describe and assess the evidence from randomized controlled trials (RCTs) concerning the efficacy and tolerability of oral sumatriptan for the treatment of a single acute attack of migraine in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (Cochrane Library, Issue 4, 2001), MEDLINE (1966 through November 2001), and reference lists of articles and books.

SELECTION CRITERIA

We included double-blind RCTs comparing oral sumatriptan (100 mg, 50 mg, 25 mg) with placebo, no intervention, other drug treatments, behavioral therapy, or physical therapy for the treatment of an acute attack of migraine in adults. Trials comparing different doses of sumatriptan or dosing regimens were also included. Outcomes considered were: 2-hour pain-free response, headache relief/headache intensity, and functional disability; headache recurrence; and adverse events.

DATA COLLECTION AND ANALYSIS

Data were abstracted by one reviewer and over-read by the other. The two reviewers independently assessed trial quality. Information on adverse events was collected from trial reports.

MAIN RESULTS

Twenty-five trials involving 16,200 participants were included. Methodological quality was generally good. Sixteen trials were placebo comparisons and showed that sumatriptan in doses of 100 mg (14 trials), 50 mg (five trials), and 25 mg (three trials) provided significantly better pain-free response (100 mg and 25 mg only), headache relief, and relief of disability at 2 hours. Numbers-needed-to-treat (NNTs) for pain-free response at 2 hours were 5.1 (3.9 to 7.1) for the 100-mg dose (n = 2221) and 7.5 (2.7 to 142) for the 25-mg dose (n = 131); there was no significant difference between the 50-mg dose and placebo for this outcome (n = 127). For headache relief at 2 hours, NNTs were 3.4 (3.0 to 4.0), 3.2 (2.4 to 5.1), and 3.4 (2.3 to 6.6) for sumatriptan 100 mg (n = 2940), 50 mg (n = 420), and 25 mg (n = 226), respectively. Precise estimates of the efficacy of the 50- and 25-mg doses relative to the 100-mg dose could not be obtained.Adverse events were more common with sumatriptan 100 mg than with placebo (risk difference [RD] = 0.14 [0.09 to 0.20]; number-needed-to-harm [NNH] = 7.1 [5.0 to 11.1]; n = 3172). RDs for the 50- and 25-mg vs. placebo comparisons were not statistically significant.

AUTHORS' CONCLUSIONS

Oral sumatriptan has been shown to be an effective drug for the treatment of a single acute attack of migraine. It is well tolerated, though minor adverse events were not uncommon in the included trials. Other triptans were generally similar in efficacy and adverse events. Among non-triptan drugs, ergotamine + caffeine was significantly less effective than sumatriptan, and other drugs have been insufficiently studied to draw firm conclusions.

Does sumatriptan cross the blood-brain barrier in animals and man?

Sumatriptan, a relatively hydrophilic triptan, based on several animal studies has been regarded to be unable to cross the blood–brain barrier (BBB). In more recent animal studies there are strong indications that sumatriptan to some extent can cross the BBB. The CNS adverse events of sumatriptan in migraine patients and normal volunteers also indicate a more general effect of sumatriptan on CNS indicating that the drug can cross the BBB in man. It has been discussed whether a defect in the BBB during migraine attacks could be responsible for a possible central effect of sumatriptan in migraine. This review suggests that there is no need for a breakdown in the BBB to occur in order to explain a possible central CNS effect of sumatriptan.

The importance of placebo in headache research

The best way to appreciate the efficacy of drug and behavioural therapy in the acute and prophylactic treatment of headache is to perform placebo-controlled randomized trials. In order to plan and conduct these studies in the most appropriate way, it is desirable to know which factors influence the placebo response. This paper reviews factors which influence the placebo response in clinical trials, such as expectation, blinding, route of application of drugs and age, gender and geographical distribution. Response rates of placebo in the treatment of acute headache episodes are higher than in headache prophylaxis. Invasive procedures such as injections have a higher placebo response compared with oral drugs. Variables known to influence the placebo response have to be taken into consideration to calculate properly the power of planned randomized trials.

Combining proof-of-concept with dose-finding: utilization of adaptive designs in migraine clinical trials

There is an obvious need to improve clinical trial designs with respect to efficiency, duration and the number of patients recruited. Adaptive (flexible) designs may be valuable in this respect. We simulated the properties of a two-stage adaptive proof-of-concept and dose-finding trial design in adult migraine patients with moderate to severe headache, with or without aura. We also assessed the usefulness of a combined Bayesian and frequentist approach in the estimation of the probability of success of subsequent Phase III studies. Applying such an innovative approach would result in a reduction of the required sample size by 30 patients and no prolongation of the trial duration. The probability of success in Phase III is > 81%. An innovative adaptive design can facilitate testing of investigational migraine medications by reducing patient numbers and improving predictivity of success in Phase III.

Clinical pharmacology of the serotonin receptor agonist, zolmitriptan

Migraine is a common, often disabling, neurovascular disease that has been shown to be associated with abnormal serotonergic activity. Drugs that modulate serotonin receptors are commonly used in the acute treatment of a migraine attack. Zolmitriptan, a 5-hydroxytryptophan(1B/1D) receptor agonist, is once such drug that is used in acute migraine therapy. Zolmitriptan is FDA approved for the treatment of acute migraine attacks and there is recent literature demonstrating its efficacy in the acute treatment of cluster attacks. It is rapidly absorbed and is detectable in the plasma within 2 - 5 min for the nasal spray formulation and within 15 min for the oral formulations. Zolmitriptan reaches peak plasma levels in 2 - 4 h and significant plasma levels are maintained for up to 6 h and lower levels for over 15 h. As zolmitriptan's metabolism is predominantly hepatic, patients with severe hepatic impairment should not receive zolmitriptan. However, only 25% of zolmitriptan is bound to plasma proteins and thus it is unlikely for drug interactions involving the displacement of highly protein-bound drugs. Zolmitriptan is generally very well tolerated and less than half of patients in clinical trials have reported adverse events, most of which are mild and transient, although rare serious cardiovascular events have been reported with all triptans. When patients are appropriately selected, zolmitriptan is both a safe and effective acute care migraine treatment. In this review the biological role of serotonin and its receptors is covered, followed by an in-depth review of the pharmacodynamics, pharmacokinetics and efficacy of zolmitriptan. Finally, the clinical application of zolmitriptan's use in patients is dicussed.

Marketed oral triptans in the acute treatment of migraine: a systematic review on efficacy and tolerability

BACKGROUND

In the current literature, there is neither a reported systematic review comparing the efficacy of triptans at 30 minutes and 1 hour after the migraine treatment, nor data related to efficacy of new marketed triptans.

OBJECTIVE

The main objective of this analysis was to compare the efficacy and tolerability of currently marketed oral, non-reencapsulated triptan formulations vs placebo in the treatment of moderate-to-severe migraine attacks.

METHODS

A systematic review of double-blind, randomized clinical trials reporting data after a single migraine attack was conducted. Efficacy results are shown using relative risk ratios with 95% confidence intervals. A sensitivity analysis was also conducted.

RESULTS

After reviewing 221 publications, 38 studies were included. All marketed triptans provided significant relief and/or absence of pain at 2 hours, and relief at 1 hour when compared with placebo. After 30 minutes, fast-dissolving sumatriptan 50 and 100 mg, sumatriptan 50 mg, and rizatriptan 10 mg showed significant relief when compared to placebo, whereas the fast-dissolving formulation of sumatriptan 100 mg was the only oral triptan that was superior to placebo in meeting the pain-free endpoint. On the other hand, fast-dissolving sumatriptan 50 and 100 mg and eletriptan 40 mg showed a lower rate of recurrence than placebo, whereas rizatriptan 10 mg was the only triptan with a recurrence rate greater than that of placebo. Adverse events associated with treatment with tablet formulations of sumatriptan and zolmitriptan were significantly more frequent than those of the placebo group. The inclusion of trials with reencapsulated triptans in the analysis introduced minor specific changes in these results.

CONCLUSION

This analysis updates the comparative data available for the 7 currently marketed oral triptans and clearly demonstrates their efficacy when compared to placebo, even with stricter endpoints, such as efficacy at 30 minutes. No triptan exhibited better tolerability than placebo. Results are diverse, depending on the triptan, which probably is a reflection of heterogeneous pharmacokinetics.

Meta-analysis of the efficacy and safety of zolmitriptan in the acute treatment of migraine

OBJECTIVE

To assess the relative efficacy and safety of zolmitriptan in the treatment of acute migraine attacks.

BACKGROUND

Zolmitriptan is a second-generation triptan developed for the treatment of migraine. Numerous randomized controlled trials (RCTs) have been carried out to compare different dosages and formulations of zolmitriptan against other treatments for acute migraine.

METHODS

Random effects meta-analysis of 24 RCTs, including 15,408 patients suffering from acute migraine attacks. Subgroup analyses compared differences in response between different dosages and formulations of zolmitriptan, and other triptan comparators.

RESULTS

Zolmitriptan 2.5 mg tablet was found to be as effective as almotriptan 12.5 mg, eletriptan 40 mg, sumatriptan 50 mg and 100 mg and more effective than naratriptan 2.5 mg in terms of 2-hour pain-free rates. Likewise, zolmitriptan 5 mg tablet was as effective as sumatriptan 50 mg and 100 mg in 2-hour pain-free rates. Compared against zolmitriptan 2.5 mg tablet, eletriptan 80 mg was more effective in achieving headache relief, pain-free and sustained pain-free responses, and rizatriptan 10 mg was more effective in terms of sustained pain-free rates. Zolmitriptan 2.5 mg tablet was associated with a lower risk of adverse events than eletriptan 80 mg but higher risk than naratriptan 2.5 mg and rizatriptan 10 mg. Zolmitriptan 5 mg tablet was superior to zolmitriptan 2.5 mg tablet in achieving 1- and 2-hour pain-free response. There were no significant differences in 1- and 2-hour headache relief and adverse event rates between the different formulations of zolmitriptan 2.5 mg.

CONCLUSIONS

Zolmitriptan 2.5 mg tablet is an effective treatment for acute attacks of migraine showing similar efficacy to almotriptan 12.5 mg, eletriptan 40 mg, and sumatriptan 50 mg, and being more effective than naratriptan 2.5 mg in terms of pain-free response at 2 hours post dose. Zolmitriptan 2.5 mg tablet was also as effective as rizatriptan 10 mg in terms of headache relief and pain-free response but less effective in terms of sustained pain-free response.

Factors associated with the prophylactic effect of placebo injections in subjects enrolled in a study of botulinum toxin for migraine

We set out to identify predictors for the prophylactic effect of placebo injections in subjects with migraine by post hoc analysis of 81 subjects with episodic migraine receiving single-blind placebo injections in a prospective trial of botulinum toxin. Possible predictors of placebo prophylaxis were compared among placebo responders (PRs) and placebo non-responders (PNRs). There were 34 PRs (42%) and 47 PNRs (58%). Male gender [odds ratio (OR) 5.83, 95% confidence interval (CI) 1.12, 30.14, P = 0.022], a history of opioid use (OR 4.44, 95% CI 1.47, 13.41, P = 0.005) and injections in the neck/shoulders (OR 2.44, 95% CI 0.93, 3.19, P = 0.033) were associated with placebo response. Of subjects with two or more of these signs, 88% were PRs compared with 31% of subjects with one or less. Male gender, opioid use and injections in the neck/shoulders are associated with placebo prophylaxis. These findings may have important implications for the design of future clinical trials and for the clinical management of migraineurs.

Optimizing migraine therapy: evidence-based and patient-centered care

Migraine is a chronic, intermittently debilitating neurovascular condition that affects the physical, mental and social aspects of health-related quality of life. Primary care provider interactions with migraine sufferers are common, highlighting the need for clinicians to provide optimal therapy. A comprehensive therapy plan should encompass the whole patient, via a patient-physician partnership where goals and strategies are mutually established. Key treatments include nondrug approaches, such as education and lifestyle modifications, to reduce the occurrence of attacks, as well as acute medications to address the immediate need for relief during an attack. Routine assessment and adjustment of therapy based on data recorded by patient diaries is paramount. Clinical trials support the use of triptans and dihydroergotamine for moderate-to-severe migraine and nonsteroidal anti-inflammatory drugs (alone or in combination with antiemetics or caffeine) for mild-to-moderate migraine, as the treatments of choice to reduce pain and disability time in a cost-effective manner. Published evidence also endorses stratified care, where medication selection is geared towards disease severity, instead of step care, where nonspecific mediations are given to all patients. Thus, patients with significant migraine-induced debilitation, as assessed by tools, such as the Migraine Disability Assessment Scale or the Headache Impact Test, are prescribed migraine-specific agents from the onset of therapy, thereby avoiding the inherent failures of step care. For individuals experiencing a high frequency of attacks or routine debilitation, preventive medications are warranted.

Distribution of intranasal C-zolmitriptan assessed by positron emission tomography

Nine healthy volunteers aged 18-28 years were recruited into this open, single-centre, two-phase trial. In phase 1, two volunteers received a single dose of 11C-zolmitriptan 2.5 mg administered as a nasal spray and then underwent positron emission tomography (PET) scanning to determine the most appropriate times for scanning in phase 2. In phase 2, six volunteers received two doses and an additional volunteer one dose of 11C-zolmitriptan 2.5 mg intranasally. Volunteers underwent PET scanning over sectors covering one of the nasopharynx, lungs or abdomen, for up to 1.5 h postdose. The brain was also scanned and plasma zolmitriptan levels were measured. Almost 100% of the administered dose was detected in the nasopharynx immediately after dosing. This declined thereafter to about 50% at 20 min and to 35% at 80 min after dosing. Radioactivity appeared slowly in the upper abdomen, with 25% of given radioactivity detected at 20 min and persisting until 80 min after dosing. Minimal radioactivity was detected in the lungs. Radioactivity was detectable within brain tissue suggesting central penetration of zolmitriptan. Zolmitriptan in plasma had approached its maximum concentration by 15 min postdose. The data indicate initial absorption across the nasal mucosa contributing to an early systemic availability. 11C-Zolmitriptan administered intranasally was well tolerated.

Oral Sumatriptan for the Acute Treatment of Probable Migraine: First Randomized, Controlled Study

OBJECTIVE

To evaluate the efficacy and tolerability of sumatriptan tablets in adults who meet International Headache Society (IHS) criteria for probable migraine but who do not meet IHS criteria for migraine with or without aura.

BACKGROUND

Headaches with some but not all of the features of migraine meet criteria for probable migraine, a form of migraine recognized by the IHS. Probable migraine attacks are also prevalent and frequently underdiagnosed.

METHODS

This was a randomized, multicenter, double-blind, placebo-controlled, parallel-group study. Adults (18 to 65 years) with a 1-year history of headaches that met 2004 IHS criteria for probable migraine without aura (same operational definition as 1988 IHS migrainous disorder) were eligible for enrollment. All patients were triptan- and ergot-naïve and had never been diagnosed with migraine. Patients were randomized in a 1:1:1:1 fashion to receive sumatriptan 25, 50, or 100 mg conventional tablets or matching placebo and were instructed to treat a single moderate or severe probable migraine attack. A post hoc analysis was conducted to evaluate the population of patients who achieved headache relief sustained throughout the immediate posttreatment period. Patients who reported relief within 2 hours and subsequently lost headache relief within 4 hours were considered nonresponders.

RESULTS

At 2 hours, more patients treated with sumatriptan achieved headache relief, the primary efficacy measure, compared with placebo, but differences only approached statistical significance for 100 mg (P= .053). The 2-hour headache relief rate in the sumatriptan 25 or 50 mg groups was not significantly different than placebo. The time to use of rescue was significantly shorter in the placebo group compared with the sumatriptan 100 mg group (P= .002). The time to use of rescue in the sumatriptan 25 or 50 mg groups was not significantly different than placebo. More patients treated with placebo (22%) lost headache relief within 4 hours compared with patients treated with sumatriptan 25 mg (17%), 50 mg (14%), or 100 mg (7%). A post hoc analysis demonstrated that at 2 hours, headache relief sustained through 4 hours (S 0-4 hours) was achieved in 44%, 49%, and 57% of patients treated with sumatriptan 25, 50, and 100 mg, respectively, compared with 34% of patients treated with placebo (P < .05 for sumatriptan 50 and 100 mg vs. placebo). All doses of sumatriptan were well tolerated and no serious adverse events were reported.

CONCLUSION

These results suggest that oral sumatriptan may be effective and is well tolerated for the acute treatment of probable migraine without aura, however, the difference between sumatriptan and placebo was not statistically significant for the a priori defined primary endpoint.

The use of unequal randomisation ratios in clinical trials: a review

OBJECTIVE

To examine reasons given for the use of unequal randomisation in randomised controlled trials (RCTs).

MAIN MEASURES

Setting of the trial; intervention being tested; randomisation ratio; sample size calculation; reason given for randomisation.

METHODS

Review of trials using unequal randomisation. DATABASES AND SOURCES: Cochrane library, Medline, Pub Med and Science Citation Index.

RESULTS

A total of 65 trials were identified; 56 were two-armed trials and nine trials had more than two arms. Of the two-arm trials, 50 trials recruited patients in favour of the experimental group. Various reasons for the use of unequal randomisation were given. Six studies stated that they used unequal randomisation to reduce the cost of the trial, with one screening trial limited by the availability of the intervention. Other reasons for using unequal allocation were: avoiding loss of power from drop-out or cross-over, ethics and the gaining of additional information on the treatment. Thirty seven trials papers (57%) did not state why they had used unequal randomisation and only 14 trials (22%) appeared to have taken the unequal randomisation into account in their sample size calculation.

CONCLUSION

Although unequal randomisation offers a number of advantages to trials the method is rarely used and is especially under-utilised to reduce trial costs. Unequal randomisation should be considered more in trial design especially where there are large differences between treatment costs.

Evaluating the triptans

The debilitating effect of migraine has fueled the search for more specific agents to treat its characteristic and associated symptoms. Second-generation oral triptans have shown an improved efficacy profile in comparison with the pioneer sumatriptan and with the over-the-counter medications and prescription analgesics that have been staples of migraine treatment. Although all triptans exert effects through the 5-hydroxytryptamine 1B/1D receptors, each triptan has distinctive pharmacokinetic properties that determine its efficacy and tolerability profile. Empirical findings based on clinical trials have led to associations between triptan pharmacology and efficacy. With the expanded treatment choices, the onus is on healthcare providers (especially primary care physicians, who see the majority of patients with migraine) to determine which treatment has an efficacy profile that best suits the individual patient's needs. Patients prefer pharmacotherapy with a rapid onset of action that facilitates complete pain relief and no recurrence. Data from published comparator trials, based on commonly used efficacy end points and pharmacokinetic properties underlying patient-preferred outcomes, are reviewed in this article.

Cost effectiveness of oral triptan therapy: a trans-national comparison based on a meta-analysis of randomised controlled trials

OBJECTIVE

The objective of this study was to appraise the relative cost effectiveness of oral triptan therapy in the management of acute migraine, comparing the results obtained using drug cost data from six different countries, USA, UK, Canada, Germany, Italy and The Netherlands.

METHOD

A meta-analysis of randomised placebo controlled trials of single dose oral triptans was carried out in order to calculate aggregate Numbers Needed to Treat (NNT) for each triptan and dose. Cost effectiveness ratios were then derived for each treatment by applying mean drug acquisition costs for each country to these NNTs. Using a graphical plot for each country, incremental cost effectiveness comparisons were then made versus sumatriptan 100 mg, the most commonly used oral triptan.

RESULTS

When analysed in terms of 2-h pain one country to another. When compared to free outcomes, rizatriptan 10 mg and eletriptan 40 and 80 mg were the most effective oral triptans. Rizatriptan 10mg has the most advantageous absolute cost effectiveness ratio in all six countries studied, although levels of statistical significance compared to other agents varied from sumatriptan 100mg, rizatriptan 10 mg and eletriptan 40 mg are most consistently the cost effective treatment choices, both being cost dominant in five out of six countries studied.

CONCLUSIONS

There are systematic differences in triptan efficacy that have an impact on treatment choice. Differences in pricing structure between countries mean that hierarchies of cost effectiveness will vary. Country-specific data should therefore be examined before defining treatment strategies.

The 40-mg dose of eletriptan: comparative efficacy and tolerability versus sumatriptan 100 mg

Meta-analysis provides valuable information regarding relative efficacies of triptans, but head-to-head comparator studies remain the gold standard. Three similar head-to-head trials comparing eletriptan 40 mg (E40) with sumatriptan 100 mg (S100) provide a rare opportunity and sufficient power, for robust comparisons of efficacy. Data were combined from three double-blind, placebo-controlled, first-dose, first-attack acute migraine treatment studies comparing E40 (n=1132), S100 (n=1129), and placebo (n=645). The primary outcome was headache response at 2 h. Secondary outcomes included headache response at 1 h, pain-free and functional responses, and sustained headache and pain-free responses. Odds ratios were calculated for summary estimates of probability of response. There were higher headache response rates with eletriptan versus sumatriptan at 2 h (67% vs. 57%; P<0.0001) and 1 h (34% vs. 26%; P<0.0001). Eletriptan also had higher 2 h pain-free (35% vs. 25%; P<0.0001) and functional responses (67% vs. 58%; P<0.0001). Sustained headache (42%) and pain-free (22%) response rates were higher for eletriptan versus sumatriptan (34%, P<0.0001; 15%, P<0.0001). The probability of response for eletriptan versus sumatriptan ranged from 36% higher (relief of nausea) to 64% higher (sustained pain-free rate). Combined analysis demonstrates that E40 has superior efficacy versus S100 across all clinically relevant outcomes.

Consequences of Transforming Measures of Efficacy for Acute Therapies: 5-HT1B/1DAgonists as a Worked Example

OBJECTIVES

To examine whether the distributions of active and placebo response rates change after transformation into therapeutic gains, numbers needed to treat, and therapeutic ratios for 51 published clinical trials of 5-HT(1B/1D) agonists in the acute treatment of migraine.

BACKGROUND

Acute migraine therapies have been compared using meta-analysis. Before pooling the results of noncontemporaneous clinical trials for meta-analysis, reconciliation of active response rates with concurrent placebo controls is done because of fluctuations in placebo response rates. The 3 common methods of reconciliation are to find for each clinical trial the therapeutic gain, the number needed to treat, or the therapeutic ratio.

METHODS

Raw active and placebo response rates were tabulated and displayed as histograms. The distributions of the therapeutic gains, numbers needed to treat, and therapeutic ratios were similarly plotted. These distributions were then compared with normal distributions using chi-squared goodness-of-fit methodology.

RESULTS

The distribution of active response rates was consistent with a normal distribution (passing a goodness-of-fit test). Placebo response rates were not normally distributed. The distribution of therapeutic gains failed a test of normality (P=.018), as did the numbers needed to treat (P <.001); the skews of these distributions were toward opposite ends of the scale for relative efficacy. The therapeutic ratios also failed a test for normality, but passed a test for log-normal distribution.

CONCLUSIONS

Choice of transformation is a potential source of bias in meta-analysis of acute migraine therapies.

Triptans for treatment of acute pediatric migraine: a systematic literature review

The purpose of this article is to evaluate the effectiveness and safety of triptans for the treatment of acute migraine in children and adolescents. Randomized and open label trials of triptans in acute pediatric patients (ages 6-18 years) were identified by Medline (1966-2002) and PubMed (1991-2002). Additional reports were identified from the reference list of the retrieved studies. To study effectiveness, only randomized controlled trials were included, but open label studies were also included to study adverse effects. Pharmacokinetic studies of triptans in pediatric patients were also searched. Four randomized controlled trials were identified. One study reported oral sumatriptan, another oral rizatriptan, and two studies reported nasal spray sumatriptan. Rizatriptan is well tolerated but not clearly beneficial when used in adolescents. Effectiveness of nasal spray sumatriptan in acute pediatric migraine where other medications had failed was supported. Effectiveness of oral sumatriptan was not established. Adverse effects were minor for oral sumatriptan and rizatriptan and nasal sumatriptan. Pharmacokinetics of sumatriptan in pediatric patients has not been established. In conclusion, nasal spray sumatriptan should be considered in acute pediatric migraine in patients not experiencing adequate relief with other interventions.

Ethical aspects of placebo in migraine research

Randomized placebo-controlled clinical trials have been the 'golden standard' during the last decades in the development of new drug therapies. This scientifically valid approach has recently been questioned in the fifth revised version of the Declaration of Helsinki, which states that the use of placebo-controlled clinical trials is only acceptable when no proven treatment exists for the studied disease. The World Medical Association further claims that no national ethical, legal or regulatory requirements should be allowed to reduce or eliminate any of the statements in the declaration. In spite of this, the document is not generally accepted as the world ethical standard, as demonstrated by its lack of adoption by many professional associations. In the evaluation process for a drug to be approved in many countries today, clinical investigators at the hospitals and researchers at the pharmaceutical companies are obliged to use study protocols that would be rejected if the new declaration were to be fully adopted. Adherence to the clinical trial guidelines of the International Headache Society could also mean violation of the new Helsinki declaration of ethics. Some ethics committees have already adopted the new declaration, which has caused concern among clinical investigators, who find this document to be vastly out of the line with common practice. At the moment, the situation is unclear and debated with increasing polarity concerning the scientific and ethical issues regarding the use of placebo in clinical trials.

The triptan formulations : how to match patients and products

The 5-HT(1B/1D) receptor agonists (the 'triptans') are migraine-specific agents that have revolutionised the treatment of migraine. They are usually the drugs of choice to treat a migraine attack in progress. Different triptans are available in various strengths and formulations, including oral tablets, orally disintegrating tablets, nasal sprays and subcutaneous injections. In Europe, sumatriptan is also available as a suppository. Specific differences among the triptans exist, as evidenced by different pharmacological profiles including half-life, time to peak plasma concentrations, peak plasma concentrations, area under the concentration-time curve, metabolism and drug-drug interaction profiles. How or whether these differences translate to clinical efficacy and tolerability advantages for one agent over another is not well differentiated. However, delivery systems may play an important role in onset of action. Given that the clinical distinctions among these agents are subtle, identification of the most appropriate triptan for an individual patient requires consideration of the specific characteristics of the patient and knowledge of patient preference, an accurate history of the efficacy of previous acute-care medications and individual features of the drug being considered. The selection of an acute antimigraine drug also depends upon the stratification of the patient's migraine attack by peak intensity, time to peak intensity, level of associated symptoms such as nausea and vomiting, time to associated symptoms, comorbid diseases and concomitant treatments that might cause drug-drug interactions. Individual patient response to the triptans seems to be idiosyncratic and possibly genetically determined. Therefore, a set of specific questions can be used to determine whether a currently used triptan is optimally effective, whether the dose needs to be increased or whether another triptan should be tried. The clinician has in his/her armamentarium an ever-expanding variety of triptans, available in multiple formulations and dosages, which have good safety and tolerability profiles. Continued clinical use will yield familiarity with the various triptans, and it should become possible for the interested physician to match individual patient needs with the specific characteristics of a triptan to optimise therapeutic benefit. Use of the methods outlined in this review in choosing a triptan for an individual patient is probably more likely to lead to migraine relief than making an educated guess as to which triptan is most appropriate.

The triptan formulations: a critical evaluation

The migraine-specific triptans have revolutionized the treatment of migraine and are usually the drugs of choice to treat a migraine attack in progress. Different triptans are available in different strengths and formulations including oral tablets, orally disintegrating tablets, nasal sprays and subcutaneous injections. In Europe, sumatriptan is also available as a suppository. Specific differences among the triptans exist as evidenced by different pharmacological profiles including T1/2, Tmax, Cmax, AUC, metabolism, drug-drug interaction profiles, amongst other parameters. How or whether these differences translate to clinical efficacy and tolerability differences is not well differentiated. Clinical distinctions among these agents are subtle and proper choice of triptan requires attention to the specific characteristics of each individual patient, knowledge of patient preference, accurate history of the efficacy of previous acute care medications as well as individual features of the drug being considered. Delivery systems may play an important role in the onset of action of triptans. The selection of an acute antimigraine drug for a patient depends upon the stratification of the patient's migraine attack by peak intensity, time to peak intensity, level of associated symptoms such as nausea and vomiting, time to associated symptoms, comorbid diseases, and concomitant treatments that might cause drug-drug interactions. The clinician has in his armamentarium an ever-expanding variety of medications, available in multiple formulations and dosages, with good safety and tolerability profiles. Continued clinical use will yield familiarity with the various triptans, and it should become possible for the interested physician to match individual patient needs with the specific characteristics of a triptan to optimize therapeutic benefit.

Safety profile of the triptans

The triptans are 5-HT(1B/1D) agonists used as migraine and cluster-specific agents. Seven are in commercial use worldwide; in order of release these are sumatriptan, zolmitriptan, rizatriptan, naratriptan, almotriptan, frovatriptan and eletriptan. Sumatriptan has been in clinical use since 1991, and although postmarketing studies have stimulated much debate of triptan strengths and weaknesses, their overall safety profile appears excellent. The most serious adverse events are cardiovascular, due to coronary artery narrowing as a consequence of coronary artery 5-HT(1B) receptor activity. Triptans are contraindicated in patients with vascular disease. Other events are even more rare, and include the potential for drug-drug interactions, based on metabolic elimination pathways. Serotonin syndrome has been a concern, but one large prospective study failed to document a single case, and reports are sporadic and not clearly causative.

Oral sumatriptan for acute migraine

BACKGROUND

Migraine is a common neurovascular disorder characterized by recurrent episodes of disabling headache, autonomic nervous system dysfunction, and, in some patients, neurological aura symptoms. Sumatriptan is one of a class of selective serotonin 5-hydroxytryptamine (5-HT1B/1D) agonists (triptans) thought to relieve migraine attacks by several mechanisms, including cranial vasoconstriction and peripheral and central neural inhibition.

OBJECTIVES

To describe and assess the evidence from randomized controlled trials (RCTs) concerning the efficacy and tolerability of oral sumatriptan for the treatment of a single acute attack of migraine in adults.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (Cochrane Library, Issue 4, 2001), MEDLINE (1966 through November 2001), and reference lists of articles and books.

SELECTION CRITERIA

We included double-blind RCTs comparing oral sumatriptan (100 mg, 50 mg, 25 mg) with placebo, no intervention, other drug treatments, behavioral therapy, or physical therapy for the treatment of an acute attack of migraine in adults. Trials comparing different doses of sumatriptan or dosing regimens were also included. Outcomes considered were: 2-hour pain-free response, headache relief/headache intensity, and functional disability; headache recurrence; and adverse events.

DATA COLLECTION AND ANALYSIS

Data were abstracted by one reviewer and over-read by the other. The two reviewers independently assessed trial quality. Information on adverse events was collected from trial reports.

MAIN RESULTS

Twenty-five trials involving 16,200 participants were included. Methodological quality was generally good. Sixteen trials were placebo comparisons and showed that sumatriptan in doses of 100 mg (14 trials), 50 mg (five trials), and 25 mg (three trials) provided significantly better pain-free response (100 mg and 25 mg only), headache relief, and relief of disability at 2 hours. Numbers-needed-to-treat (NNTs) for pain-free response at 2 hours were 5.1 (3.9 to 7.1) for the 100-mg dose (n = 2221) and 7.5 (2.7 to 142) for the 25-mg dose (n = 131); there was no significant difference between the 50-mg dose and placebo for this outcome (n = 127). For headache relief at 2 hours, NNTs were 3.4 (3.0 to 4.0), 3.2 (2.4 to 5.1), and 3.4 (2.3 to 6.6) for sumatriptan 100 mg (n = 2940), 50 mg (n = 420), and 25 mg (n = 226), respectively. Precise estimates of the efficacy of the 50- and 25-mg doses relative to the 100-mg dose could not be obtained. Adverse events were more common with sumatriptan 100 mg than with placebo (risk difference [RD] = 0.14 [0.09 to 0.20]; number-needed-to-harm [NNH] = 7.1 [5.0 to 11.1]; n = 3172). RDs for the 50- and 25-mg vs. placebo comparisons were not statistically significant.

REVIEWER'S CONCLUSIONS

Oral sumatriptan has been shown to be an effective drug for the treatment of a single acute attack of migraine. It is well tolerated, though minor adverse events were not uncommon in the included trials. Other triptans were generally similar in efficacy and adverse events. Among non-triptan drugs, ergotamine + caffeine was significantly less effective than sumatriptan, and other drugs have been insufficiently studied to draw firm conclusions.

Assessing the efficacy of drugs for the acute treatment of migraine: issues in clinical trial design

Clinical trials of therapies for acute migraine attacks have evolved over the years from open-label, small observational studies to highly structured randomised, controlled trials. The International Headache Society Committee on Clinical Trials in Migraine developed a tool to guide in designing scientifically sound trials. The proof of effect is best achieved in a clinical trial with: clearly defined objectives;a well-characterised study population, identified using well-validated diagnostic tools;proper randomisation and blinding;inclusion of a placebo arm, with proper balancing of patients receiving placebo and those receiving active drug;adequate study power; and appropriate statistical methods. Both parallel and crossover studies may be suitable in clinical trials of antimigraine agents, although the latter are a better choice in patient preference and bioequivalence studies. Although various efficacy measures are used to assess treatment effect, the 2-hour pain free rate (total resolution of pain within 2 hours after an initial moderate to severe headache) is preferred because it is clinically relevant and is relatively 'placebo-insensitive'. Various migraine surveys have indicated that a rapid onset of therapeutic effect is a highly desirable attribute of an antimigraine drug. Therefore, accurate measurements of treatment effect before 2 hours are becoming increasingly emphasised. Consistency of effect across multiple attacks adds to the understanding of the therapeutic efficacy of a test drug. Finally, preference and satisfaction studies allow us to assess patients' global impression of a particular treatment, weighing the positive effects on pain and associated symptoms of migraine against potential adverse effects.

A quantification of the placebo response in migraine prophylaxis

To quantify the placebo response of prophylactic therapy in migraine, a meta-analysis of prophylactic, double-blind, placebo controlled migraine studies was performed. The total analysis included 22 studies testing 19 different products, including 2013 patients, of which 828 were treated with placebo. A reduction in migraine attacks of 50% or more (responders) was seen in 23.5%+/-8.0 (95% C.I. 18.3-28.8%) of the patients in the placebo groups and 45.5%+/-15.5 (95% C.I. 37.4-53.6%) in the active groups. A reduction in migraine attacks of 16.8%+/-12.7 (95% C.I. 10.9-22.6%) was observed in the placebo groups and 41.8%+/-11.7 (95% C.I. 36.9-46.6%) in the active groups. We propose that if the percentage of responders in an open-label prophylactic trial in migraine is above 35-40%, or if a reduction in migraine attack frequency is found of 40% or more, further studies are indicated to determine the prophylactic activity of the drug. In all studies included in this analysis, no placebo response was seen above these limits.

Triptans: do they differ?

Headache care specialists agree that the introduction of sumatriptan constitutes a major advance in headache therapy, but they differ about whether other triptans offer clinically significant advantages over sumatriptan. This article examines this issue by considering the similarities and differences among triptans.

How does almotriptan compare with other triptans? A review of data from placebo-controlled clinical trials

Almotriptan, the new selective 5-HT1B/1D agonist, has a higher oral bioavailability than any other triptan, with more than two thirds of the administered dose absorbed within the first hour both inside and outside of a migraine attack. Gender or the presence of food in the stomach does not affect its pharmacokinetic profile, and the compound has no clinically relevant interactions with other drugs. Among the available triptans, response rates at 2 hours range from 50% to 80%, with 20% to 50% of patients pain-free. Almotriptan 12.5 mg provides similar efficacy, with significant advantage over placebo at 30 minutes and a reliable consistency (75% in two of three attacks). Headache typically recurs in 25% to 45% of patients with most triptans. The recurrence rate with almotriptan 12.5 mg, 18% to 27%, is among the lowest reported. The tolerability of almotriptan 12.5 mg is close to that of placebo with a low incidence of central nervous system side effects and chest symptoms. In conclusion, almotriptan's consistent pharmacokinetics and good efficacy, in combination with excellent tolerability, make it an attractive choice in the acute treatment of migraine attacks.

Advances in pharmacological treatment of migraine

Migraine is a paroxysmal disorder with attacks of headache, nausea, vomiting, photo- and phonophobia and malaise. This review summarises new treatment options both for the therapy of the acute attack as well as for migraine prophylaxis. Analgesics like aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) are effective in treating migraine attacks. Few controlled trials were performed for the use of ergotamine or dihydroergotamine. These trials indicate inferior efficacy compared with serotonin (5-HT(1B/D)) agonists (triptans). The triptans (almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, sumatriptan and zolmitriptan), are highly effective. They improve headache as well as nausea, photo- and phonophobia. The different triptans show only minor differences in efficacy, headache recurrence and adverse effects. The knowledge of their different pharmacological profile allows a more specific treatment of the individual migraine characteristics. Migraine prophylaxis is recommended, when more than three attacks occur per month, if attacks do not respond to acute treatment or if side effects of acute treatment are severe. Substances with proven efficacy include the beta-blockers metoprolol and propranolol, the calcium channel blocker flunarizine, several 5-HT antagonists and amitriptyline. Recently anti-epileptic drugs (valproic acid, gabapentin, topiramate) were evaluated for the prophylaxis of migraine. The use of botulinum toxin is under investigation.