Assessing the onset of relief of a treatment for migraine

Guidelines of the International Headache Society for controlled trials of acute treatment of migraine attacks in adults: Fourth edition

The quality of clinical trials is an essential part of the evidence base for the treatment of headache disorders. In 1991, the International Headache Society Clinical Trials Standing Committee developed and published the first edition of the Guidelines for controlled trials of drugs in migraine. Scientific and clinical developments in headache medicine led to second and third editions in 2000 and 2012, respectively. The current, fourth edition of the Guidelines retains the structure and much content from previous editions. However, it also incorporates evidence from clinical trials published after the third edition as well as feedback from meetings with regulators, pharmaceutical and device manufacturers, and patient associations. Its final form reflects the collective expertise and judgement of the Committee. These updated recommendations and commentary are intended to meet the Society's continuing objective of providing a contemporary, standardized, and evidence-based approach to the conduct and reporting of randomised controlled trials for the acute treatment of migraine attacks.

A Randomized, Controlled, Crossover Trial to Investigate Times to Onset of the Perception of Soothing and Cooling by Over-The-Counter Heartburn Treatments

This was a randomized, controlled, four-way crossover study in 45 subjects with a tendency to suffer from moderate heartburn following some meals. The study was designed to assess the time to onset of the perceived soothing and cooling effects of the alginate raft-forming products, Gaviscon Liquid (peppermint), Gaviscon Double Action Liquid (peppermint) and Gaviscon Powder Formulation (fresh tropical), compared with a non-active sublingual control. All three Gaviscon products provided significantly faster soothing and cooling effects compared with the control. Based on the upper 95% confidence limits for the median, time to onset of soothing was perceived within 3.15 min, 3.08 min and 4.05 min for Gaviscon Liquid, Double Action Liquid and Powder Formulation, respectively. Similarly, time to onset of cooling was perceived within 1.95 min, 1.23 min and 11.22 min for Gaviscon Liquid, Double Action Liquid and Powder Formulation, respectively. The results show that Gaviscon Liquid and Gaviscon Double Action soothe within 3.15 min and cool within 1.95 min.

Comparative sensitivity of stopwatch methodology and conventional pain assessment measures for detecting early response to triptans in migraine: results of a randomized, open-label pilot study

BACKGROUND

The standard measure of efficacy used in migraine trials is a 4-point patient-rated headache pain intensity (HPI) scale. However, it has been suggested that using a stopwatch to measure the time to meaningful pain relief can provide a more precise measurement of treatment response.

OBJECTIVE

This study evaluated the sensitivity of a stopwatch method for detecting meaningful relief of headache pain and the correlation of this method with the HPI scale and a 5-point pain relief scale.

METHODS

In this open-label, parallel-group pilot study, patients were randomized to receive oral eletriptan 40 mg, eletriptan 80 mg, or rizatriptan 10 mg for the treatment of a single acute migraine attack. The effect of study treatment on migraine pain was assessed immediately before dosing and at 0.5, 1, 1.5, 2, 3, and 4 hours after dosing. At each time point, patients recorded the 3 types of pain assessment in a patient diary. HPI was rated using the standard 4-point International Headache Society pain intensity scale (from 0 = no pain to 3 = severe pain). Pain relief was rated on a 5-point pain relief scale (from 4 = no relief to 0 = complete relief). The time to the onset of meaningful pain relief was measured using a stopwatch. At 4 hours after dosing, patients provided a global rating of the overall efficacy of study medication on a 5-point scale (from 0 = poor to 4 = excellent).

RESULTS

Seventy-nine patients participated in the trial (78.5% female; mean [SD] age, 37.7 [9.8] years; 58.2% white). The median times to meaningful pain relief measured by stopwatch were 84, 72, and 93 minutes for eletriptan 40 mg, eletriptan 80 mg, and rizatriptan 10 mg, respectively (log-rank P = 0.029, eletriptan 80 mg vs rizatriptan 10 mg). At 90 minutes (approximating the median time to meaningful pain relief on the stopwatch), headache response rates using HPI scoring (mild to no pain) were 65%, 68%, and 52% in the respective treatment groups, with no significant difference between groups. On the pain relief scale, the corresponding mean (SD) scores at 90 minutes were 1.6 (1.2), 1.4 (1.3), and 2.0 (1.4) (P = NS). The pain relief-defined response (> or = 75% pain relief) at 90 minutes did not differ significantly between the 3 treatment groups (62%, 56%, and 48%). Detection of early improvement (0.5 and 1 hour) was similar with the HPI and pain relief scales.

CONCLUSION

The results of this open-label pilot study suggest the convergent validity of 3 pain-assessment methods in migraine, but indicate that the use of a stopwatch may be a more sensitive method for detecting between-group differences.

Clinically Significant Change in Pain Intensity Ratings in Persons With Spinal Cord Injury or Amputation

OBJECTIVE

To examine the clinical significance of changes in chronic pain in 2 disability groups: spinal cord injury and lower limb amputation.

METHODS

A reanalysis of 2 controlled clinical trials for pain in persons with disabilities. Eighty-two persons with spinal cord injuries and 34 persons with amputations provided pretreatment and posttreatment ratings of pain intensity on 0 to 10 numerical rating scales. After treatment, participants also rated the meaningfulness of any changes in pain they experienced.

RESULTS

An average decrease of 1.80 points on the 0 to 10 numerical rating scales and percent decreases of about 36% corresponded to reports of a meaningful change in pain. There was no significant difference between samples, and also no differences due to gender or treatment condition. Age and pretreatment pain, however, were associated with the amount of pain decrease rated as meaningful. The change in pain intensity rated as meaningful was greater for older participants and participants with higher levels of pretreatment pain. Consistent with previous research, percent change scores were less biased by pretreatment pain than were absolute change scores.

DISCUSSION

These findings are generally consistent with similar findings in other pain populations, and, in light of previous research, support an approximate 33% decrease in pain as a reasonable standard for meaningful change across chronic pain conditions. Percent change scores may be more useful for comparing the effects of pain treatments across samples or conditions because they are less biased by pretreatment pain level.

Onset of effect of 5-HT1B/1D agonists: a model with pharmacokinetic validation

OBJECTIVE

To quantitate onset of effect of all formulations of sumatriptan, and to investigate whether this is related to rate, not extent, of drug absorption.

METHODS

From published literature, for 4 formulations of sumatriptan and matching placebos, response rates were modeled using a simple logarithmic equation, with a being a parameter of curve convexity and B, a location parameter (equal to response rate at 2 hours [the standard regulatory parameter]). The average rate of drug absorption (A) was estimated by dividing the maximal drug concentration by the time needed to achieve it (Cmax/Tmax). Least mean square correlation was then performed between the therapeutic gains and therapeutic ratios of curve convexity and rate of drug absorption.

RESULTS

-Models closely fitted observed response rates (2 hours or less). Curve convexity correlated with rate of drug absorption. Sumatriptan response rates (0 to 2 hours) for formulations correlated with rate, not extent, of drug absorption. The range of rates of onset of effect among different routes of administration was greater than that for tablets with 4-fold differences in dose size.

CONCLUSION

Onset of effect is related to rate of absorption of sumatriptan. There is greater scope for improving onset of effect using an alternative route of administration than by increasing the oral dose.

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.