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

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.

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.

Clinical trial: the glucagon-like peptide-1 analogue ROSE-010 for management of acute pain in patients with irritable bowel syndrome: a randomized, placebo-controlled, double-blind study

BACKGROUND

There is currently no treatment available to manage acute pain attacks in IBS patients regardless of subtype.

AIMS

To evaluate efficacy and safety of the GLP-1 analogue ROSE-010 in patients with irritable bowel syndrome (IBS) through a randomized, double-blind, placebo-controlled study.

METHODS

Eligible patients (n = 166) meeting Rome II criteria were randomly assigned to receive single subcutaneous injections of ROSE-010 100 microg, 300 microg and placebo in a cross-over design. Safety was assessed from spontaneously reported adverse events and measurement of vital signs. Patient-rated pain relief and intensity were measured on a 100-mm visual analogue scale. The primary efficacy variable was proportion of patients with >50% maximum total pain relief response from 10 to 60 min after treatment. Secondary endpoints included the maximum summed pain intensity difference, time to meaningful pain relief and patient ratings of satisfaction with treatment.

RESULTS

Twice as many patients were responders in the primary efficacy endpoint after both ROSE-010 injections compared to placebo (24%P = 0.011, 23%P = 0.005, and 12% after 300 microg, 100 microg and placebo injections, respectively). Similar results were obtained for the proportion of patients with total pain intensity response. Times to meaningful and total pain relief were shorter for both doses of ROSE-010 compared with placebo. Compared with placebo, more patients (P < 0.05) were satisfied with ROSE-010 and considered ROSE-010 better than previous IBS medications used.

CONCLUSION

ROSE-010 was well tolerated and provided fast and effective relief of acute pain attacks on demand in IBS patients.

Inhaled insulin delivery--where are we now?

Since 1925, when the concept of treating diabetes with inhaled insulin (INH) was originally published, a number of clinical challenges have been resolved through technological advancements. Efforts by pharmaceutical partnerships or individual companies have resulted in the development of both injection-free devices and novel insulin formulations. Four different INH systems are now in phase 3 of clinical development, and several other INH systems are in earlier stages of clinical study. Clinical data consistently demonstrate that INH therapy is comparable to subcutaneous (SC) therapy in improving glycaemic control in patients with either type 1 or type 2 diabetes, generally without greater risk of overall hypoglycaemia. INH is generally well tolerated and appears to be safe. Adverse-event profiles for INH therapies are similar to SC insulin therapy, with the majority of events being reported as being mild to moderate. Long-term safety studies are ongoing, with emphasis on evaluating the impact of INH therapy on pulmonary function and immune responses. Although small, reversible decreases in pulmonary diffusion capacity (DL(co)) and FEV1 have been reported in response to INH, pulmonary function and structure do not appear to be affected in any clinically significant way. While insulin antibodies are increased in INH therapy, these antibodies have not been correlated with haemoglobin A1c (HbA1c), insulin dosage, hypoglycaemia, pulmonary function or adverse events. Nevertheless, properly controlled, long-term studies will best answer any remaining concerns. From the patient's perspective, INH therapy is preferred by the majority of patients over conventional SC insulin therapy. Studies have shown that patients prefer INH therapy, because it provides greater lifestyle flexibility and social acceptability while at the same time avoiding the pain associated with injection. Thus, after more than 80 years during which the injection route has been the only means of administering insulin, patients and physicians may soon avail themselves of another valuable tool in management of diabetes.

Efficacy and safety of preprandial human insulin inhalation powder versus injectable insulin in patients with type 1 diabetes

AIMS/HYPOTHESIS

The efficacy and safety of human insulin inhalation powder (HIIP) plus insulin glargine were compared to subcutaneously injected insulin (SC insulin) plus insulin glargine in patients with type 1 diabetes.

METHODS

This was a randomised, open-label crossover study in which one group of patients received preprandial HIIP plus insulin glargine for 12 weeks, followed by the same duration with preprandial SC insulin (lispro or regular) plus insulin glargine. Another group of patients received the reverse treatment sequence. The trial was designed as a non-inferiority comparison of the two treatments for effect on HbA(1c); blood glucose levels were also monitored. Safety assessments included adverse event reporting and hypoglycaemic events.

RESULTS

HbA(1c) at endpoint was 7.95+/-0.12% for the HIIP treatment and 8.06+/-0.12% for the SC insulin treatment; mean changes from baseline to endpoint were -0.08 and 0.00%, respectively, (p=NS). The upper limit of the 95% CI of mean difference in HbA(1c) between the two treatments was 0.02%, indicating that HIIP was not inferior relative to SC insulin, as measured against the pre-defined margin of 0.3%. Fasting blood glucose was significantly lower for HIIP treatment (8.09+/-0.33 mmol/l; n=117) than for SC insulin treatment (9.05+/-0.33 mmol/l; n=111) (p=0.01). Safety profiles were comparable between the two treatments. The rate of any hypoglycaemia (least-squares mean adjusted for 30 days+/-SE) was 8.9+/-0.7 and 8.2+/-0.8 for HIIP and SC insulin treatments, respectively, (p=0.29). The rate of nocturnal hypoglycaemia was greater for HIIP (4.2+/-0.4) than for SC insulin (2.7+/-0.4; p<0.001).

CONCLUSIONS/INTERPRETATION

HIIP was similar in efficacy to SC insulin for glycaemic control in type 1 diabetes mellitus. The two treatments had comparable safety profiles.