Sum of Pain Intensity Differences (SPID) in migraine trials. A comment based on four rizatriptan trials

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.

Early Onset of Efficacy and Consistency of Response Across Multiple Migraine Attacks From the Randomized COMPASS Study: AVP-825 Breath Powered® Exhalation Delivery System (Sumatriptan Nasal Powder) vs Oral Sumatriptan

OBJECTIVE

To further characterize the clinical utility of AVP-825 based on additional prespecified outcomes and post hoc analyses of COMPASS, a Phase 3 comparative efficacy trial of AVP-825 vs 100 mg oral sumatriptan (NCT01667679). AVP-825 was approved in January 2016 by the US Food and Drug Administration under the name ONZETRA^® Xsail^® (sumatriptan nasal powder) for the acute treatment of migraine with or without aura in adults.

BACKGROUND

AVP-825 is a delivery system that uses a patient's own breath to deliver low-dose sumatriptan powder to the upper posterior regions of the nasal cavity beyond the narrow nasal valve, areas lined with vascular mucosa conducive to rapid drug absorption into the systemic circulation. The recommended dose of AVP-825 is 22 mg sumatriptan powder administered as one 11 mg nosepiece in each nostril, which delivers approximately 15-16 mg of sumatriptan intranasally. The COMPASS trial compared AVP-825 22-100 mg oral sumatriptan across multiple migraine attacks for efficacy, safety, and tolerability endpoints.

DESIGN/METHODS

COMPASS was a randomized, multicenter, double-dummy, crossover, multiattack, comparative efficacy study with two 12-week double-blind periods. Patients with 2-8 migraine attacks/month were randomized 1:1 to AVP-825 (22 mg) plus oral placebo or an identical placebo delivery system plus 100 mg oral sumatriptan for the first period, and then patients switched treatments for the second period. Patients treated up to 5 qualifying migraines per period within 1 h of onset, even if the intensity of the attack was mild. Results from the primary endpoint (SPID-30, defined as the sum of pain intensity differences from dosing to 30 minutes), key secondary efficacy endpoints and safety assessments have been reported in the primary publication (Tepper et al., 2015). This article reports additional prespecified outcomes, including the SPID-30 for attacks treated when baseline severity was mild vs moderate/severe, measures of sustained response and consistency of effect in patients who experienced multiple migraine attacks, and the results of post hoc analyses performed to assess total migraine freedom (defined as no pain and no migraine-associated symptoms, including nausea, vomiting, photophobia, and phonophobia), time to pain freedom, time to meaningful pain relief, and local (occurring at the site of administration in the nose) vs systemic treatment-emergent adverse events (TEAEs).

RESULTS

A total of 185 patients completed both treatment periods, yielding 1,531 migraine attacks which were treated and assessed (765 AVP-825, 766 oral sumatriptan). Treatment with AVP-825 provided greater reduction in migraine pain intensity which was statistically significant vs oral sumatriptan in the first 30 minutes postdose regardless of whether attacks were treated when pain was mild (least squares mean SPID-30 = 3.90 vs 0.24, P = .0013) or moderate/severe (least squares mean SPID-30 = 13.83 vs 10.07, P = .0002). At every time point from 15 to 90 minutes postdose, the proportion of attacks achieving total migraine freedom was greater and statistically significant after treatment with AVP-825 vs 100 mg oral sumatriptan. AVP-825 treatment resulted in greater odds of achieving pain freedom (odds ratio, OR = 1.29, P < .01) and meaningful pain relief (OR = 1.32, P < .0001), which were also statistically significant compared with oral sumatriptan. In addition, a greater proportion of attacks treated with AVP-825 vs oral sumatriptan was associated with sustained pain freedom, achieving statistical significance when assessed from 1 h postdose through 24 hours postdose (33.3% vs 27.9%; P < .05) and through 48 hours postdose (32.7% vs 27.4%; P < .05). For patients who treated multiple migraine attacks in both treatment periods, a greater proportion had consistent pain relief and pain freedom following treatment with AVP-825 compared to oral sumatriptan across multiple attacks, a difference that achieved statistical significance at 30 minutes postdose. Local TEAEs of abnormal taste and nasal discomfort were more common following AVP-825 treatment. Of the patients experiencing either of these TEAEs, about 90% described the intensity as mild, and only one discontinued treatment because of either of these two TEAEs.

CONCLUSIONS

These results from the COMPASS study further demonstrate that treatment with AVP-825 provides earlier onset and more consistent across-episode improvement of pain and migraine-associated symptoms compared with oral sumatriptan, highlighting the clinical advantages of this newly approved intranasal delivery system for low-dose sumatriptan powder.

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.

Responsiveness of efficacy endpoints in clinical trials with over the counter analgesics for headache

AIM

To quantify and compare the responsiveness within the meaning of clinical relevance of efficacy endpoints in a clinical trial with over the counter (OTC) analgesics for headache. Efficacy endpoints and observed differences in clinical trials need to be clinically meaningful and mirror the change in the clinical status of a patient. This must be demonstrated for the specific disease indication and the particular patient population based on the application of treatments with proven efficacy.

METHODS

Patient's global efficacy assessment during two study phases (pre-phase and treatment phase) was used to classify patients as satisfied or non-satisfied with the efficacy of their medication. The analysis is based on 1734 patients included in the efficacy analysis of a randomized, placebo-controlled, double-blind, multi-centre parallel group trial with six treatment arms. Based on this classification and the pain intensity recorded by the patients on a 100 mm visual analogue scale, group differences by assessment categories and receiver operating characteristic (ROC) curve methods were used to quantify responsiveness of the efficacy endpoints 'time to 50% pain relief', 'time until reduction of pain intensity to 10 mm', 'weighted sum of pain intensity difference' (%SPIDweighted), 'pain intensity difference (PID) relative to baseline at 2 hours', and 'pain-free at 2 hours'.

RESULTS

Clinically relevant differences between patients satisfied and non-satisfied with the treatment were observed for all efficacy endpoints. Patients with the highest rating of efficacy had the fastest and strongest pain relief. In comparison, patients assessing efficacy as 'less good' reached a 50% pain relief on average nearly an hour later than those scoring efficacy as at least 'good'. Simultaneously, their extent of pain relief was only half as great 2 hours after medication intake. Patients scoring efficacy as 'poor' experienced practically no pain relief within the 4 hour observation interval. ROC curve calculations confirmed an adequate responsiveness for all continuous endpoints. The following cut-off points for differentiating between satisfied and non-satisfied patients were deduced from the data in the pre- and treatment phase, respectively: 'time to 50% pain relief' 1:10 and 1:31 h:min, 'time until reduction of pain intensity to 10 mm' 2:40 and 3:00 h:min, '%SPIDweighted' 68 and 64%, 'PID at 2 hours' 35 and 35 mm. The sensitivity and specificity based on these cut-off points ranged from 70 to 79%. The binary endpoint 'pain-free at 2 hours' showed a clearly higher specificity (80 and 87%) than sensitivity (65 and 61%) in the pre- and treatment phase, respectively.

CONCLUSIONS

When global assessment of efficacy by the patient was used as external criterion, ROC curve calculations confirmed a high responsiveness for all efficacy endpoints included in this study. Clinically relevant differences between patients satisfied and non-satisfied with the treatment were observed. The endpoint '%SPIDweighted' proved slightly but consistently superior to the other endpoints. SPID and %SPIDweighted are not easy to interpret and the time course of pain reduction is of high importance for the patients in the treatment of acute pain, including headache. The endpoint 'pain-free at 2 hours' showed the expected high specificity, but at the cost of a concurrently low sensitivity and clearly makes less use of the available information than the endpoint 'time to 50% pain reduction', which combines the highly relevant aspects of time course and extent of pain reduction. Responsiveness, the ability of an outcome measure to detect clinically important changes in a specific condition of a patient, should be added in future revisions of IHS guidelines for clinical trials in headache disorders.

Comparative evaluation of efficacy and safety of etodolac and diclofenac sodium injection in patients with postoperative orthopedic pain

OBJECTIVE

The objective of this study was to compare the analgesic efficacy of etodolac injection and diclofenac injection in patients with postoperative orthopedic pain.

METHODS

This was multicentric, randomized, assessor-blind and parallel-group study. A group of 158 patients with moderate to severe pain following orthopedic surgery were randomly assigned to receive either etodolac 400 mg twice a day (n = 78) or diclofenac 75 mg thrice a day (n = 80).

MAIN OUTCOME MEASURES

The primary efficacy outcome measures were pain intensity difference, sum of pain intensity differences and pain relief whereas secondary efficacy variables included maximum fall in pain intensity, number of doses of study medication consumed, number of patients who required rescue medication and overall response to therapy.

RESULTS

Mean pain intensity differences assessed on 10 cm VAS were significantly better for etodolac arm compared to diclofenac arm at 4, 8, 20 and 24 hours (p < 0.05). Sum of pain intensity differences over the first 8 hours (-21.31 ± 6.26 for etodolac vs. -19.13 ± 6.98 for diclofenac; p = 0.041) and over the 24 hours (-39.83 ± 10.70 for etodolac vs. -35.25 ± 12.00 for diclofenac; p = 0.012) for the etodolac group was significantly superior than diclofenac group. Assessment of pain relief showed that etodolac injection was significantly more effective than diclofenac injection (p < 0.0001) over the 24 hour assessment period. Maximum fall in pain intensity score, number of doses of study medication consumed and patients' and investigators' overall response to the drug at the end of treatment period were also significantly superior in the etodolac arm as compared to the diclofenac arm (p < 0.05). However, the number of patients who were rescued was comparable in both the treatment arms. A change in emotional functioning of the patients was not captured in this study. Both the study medications were well tolerated with no incidence of SAE throughout the study.

CONCLUSION

Etodolac can be considered as an effective alternative to traditional NSAIDS in the treatment of post operative pain.

Treatment of breakthrough pain with fentanyl buccal tablet in opioid-tolerant patients with chronic pain: appropriate patient selection and management

BACKGROUND

Opioids can be a safe and effective option for carefully selected patients with a structured treatment program that includes consistent monitoring. However, the benefits and risks of opioid therapy for patients with chronic pain, and society as a whole, have been sharply debated. A key component of this debate has involved the administration of rapid-onset opioids for the management of breakthrough pain.

OBJECTIVE

Review key aspects of breakthrough pain management with fentanyl buccal tablet, with a focus on minimizing risk to optimize therapeutic outcomes. Recommendations that apply broadly to all rapid-onset opioids are also discussed.

DESIGN

Available fentanyl buccal tablet clinical and post-marketing data were reviewed.

RESULTS

Like other schedule II controlled substances, and because fentanyl buccal tablet is a highly potent opioid, its use is associated with risk of overdose, misuse, and diversion. As with all rapid-onset opioids, particular attention to patient selection and risk assessment is warranted. The inclusion and exclusion criteria in fentanyl buccal tablet clinical studies represent patient selection standards that should be translated to clinical practice, most importantly, that patients are opioid-tolerant before fentanyl buccal tablet initiation. Titration of fentanyl buccal tablet from a low starting dose to a successful dose allows the safe identification of a dose that provides the greatest pain relief without unacceptable adverse events. After initiating fentanyl buccal tablet therapy, all patients should continue to be regularly monitored for response, including analgesia, functioning, tolerability, and aberrant behavior.

CONCLUSIONS

Fentanyl buccal tablet can be an effective and generally safe treatment for breakthrough pain when appropriate patient selection, administration, dosing, and monitoring are applied.

A vertical VAS is a valid instrument for monitoring headache pain intensity

Visual analogue scales (VAS) are well-validated instruments for assessing pain intensity, but have an impractical format. The aim of the study was to validate a vertical against a horizontal VAS for pain intensity registration. Out-patients with headache or non-headache pain were included. Participants completed a horizontal and a vertical VAS. Both were completed twice for test-retest. Headache was diagnosed according to the International Classification of Headache Disorders, 2nd edition. The results on vertical and horizontal VAS did not differ significantly in the different headache or chronic pain groups. For test-retest evaluation, effect sizes and Cohen's delta values were < 0.029 with < 1.5% change from test to retest (P < 0.01). Correlation coefficients were > 0.95. Bland-Altman analysis showed good agreement between vertical and horizontal scores with correlation coefficients > 0.84. A vertical VAS is equally valid as a horizontal VAS for registration of pain intensity in headache and non-headache patients.