Monotherapy trials: endpoints

Initial monotherapy with eslicarbazepine acetate for the management of adult patients with focal epilepsy in clinical practice: a meta-analysis of observational studies

AIM OF THE STUDY

To assess the effectiveness, overall tolerability of eslicarbazepine acetate (ESL) as an initial or early monotherapy treatment of adult patients with focal epilepsy under real-world practice conditions.

MATERIALS AND METHODS

We focused on real-world longitudinal studies that included or separately reported the results of at least one of the efficacy outcomes of interest. A DerSimonian-Laird random effects model was used with the presentation of the 95% confidence intervals of the estimate.

RESULTS

5 studies met our selection criteria and were included in the quantitative synthesis. All studies were observational and uncontrolled studies, and all but one were retrospective studies. The pooled proportion of patients who were seizure-free for the entire study period was 64.6% (95% CI, 45.7 to 79.8) at month 6 and 56.6% (95% CI, 50.2 to 62.8) at month 12. Pooled retention rates were 95.0% (95% CI, 90.3 to 97.5) at 6 months and 83.6% (95% CI, 73.9 to 90.1) at 12 months. The pooled proportion of patients who reported at least one adverse event was 27.2% (95% CI, 21.7 to 33.6), and the pooled proportion of patients who discontinued ESL due to adverse events was 8.9% (95% CI 6.2 to 12.6).

CONCLUSIONS

Our results suggest that initial or early monotherapy with ESL is effective and well-tolerated for the management of adult patients with focal epilepsy in clinical practice, with results that are at least similar to those reported in the pivotal randomized clinical trial of ESL monotherapy. No new safety signals with ESL have been identified in this systematic review.

Development of outcome criteria to measure effectiveness of antiepileptic therapy in children

PURPOSE

Clinical trials of antiepileptic drugs frequently measure outcomes of seizure control, which demonstrate efficacy. Yet, functional status, quality of life, and long-term treatment effects reflecting effectiveness are scarcely assessed. We sought to use a consensus method to help identify which outcome criteria key stakeholders consider should be used to measure effectiveness in trials of antiepileptic treatments for children.

METHOD

A two-round Delphi survey was used; parents of children with epilepsy and local, international experts comprising academics and clinicians participated in the survey. In the first round, 32 experts, 50 parents, and 15 children with epilepsy aged >13years suggested outcomes that they considered important in determining effectiveness of antiepileptic therapy in children, separately for preschool and school age. In the second round, 29 experts and 42 parents scored the importance of outcomes from the list suggested by at least 10% of round 1 respondents and also proposed five most important outcomes.

RESULTS

Complete seizure freedom (67%), seizure frequency (48%), ability to perform normal day-to-day activities (45%), and quality of life (40%) were identified as the most important outcomes of antiepileptic therapy in children of both age groups. Additionally, effect on developmental milestones (47%) and child's compliance to treatment regimen (39%) were identified as most important in preschool age group and school performance (49%); adverse effects (39%) were identified as most important in school age group.

CONCLUSION

For the first time, this study has identified outcome priorities regarding antiepileptic treatment in children based on the key stakeholders' perspectives. It could be used as a provisional list of outcomes for inclusion in a core outcome set for children with epilepsy.

Factors influencing on quality of life in people with epilepsy

OBJECTIVES

To assess the influence of different factors on health-related QOL in adults with epilepsy in Moscow, Russia.

METHOD

We evaluated quality of life in 242 patients (98 de novo and 144 previously inadequately treated) by using QOLIE-31. Partial cryptogenic or symptomatic epilepsy was diagnosed in 214 patients, in 28-idiopathic generalized epilepsy. Stepwise regression analysis was performed to assess the influence of different factors on QOL.

RESULTS

In patients with epilepsy in Russia the total score of QOLIE-31 was rather low-42.13+/-4.14. Relationship of quality of life (total score) and frequency of seizures and duration of disease was analyzed. Frequency of seizures was the most significant parameter related to QOL (R=0.46 with total score). Duration of disease also correlated with QOL score (R=0.24 with total score). Significant but rather weak association (link) between frequency of seizures and almost all of subscales of quality of life was noticed. Duration of epilepsy correlated with less number of subscales: Energy/fatigue, Medication effects, Social functioning, Overall QOL subscales. When factors influencing on QOL were separately analyzed in newly diagnosed and previously treated patients frequency of seizures was the most important parameter in both groups.

CONCLUSIONS

Frequency of seizures is the most important factor influencing on QOL in adults with epilepsy (newly diagnosed and previously treated).

Epilepsy and quality of life in adults: A review of instruments

The aim of this report is to describe the state of the art of quality of life (QoL) instruments used for adults with epilepsy and to help those in the field to identify, select, and use the instruments most suitable for their purposes. We searched Medline and the Cochrane Database for articles in English, German, French, Spanish, Portuguese and Italian published by the end of 2002. Electronic retrieval was completed by hand-search. The final list included 203 articles reporting 205 studies. There were 62 validation studies and 143 clinical studies, including 7 population studies, 45 "pure" observational, 37 observational with aspects of validation and 54 experimental (38 randomized clinical trials and 16 non-randomized or non-controlled trials). Twenty-four generic and 21 specific QoL instruments were used. Eight were used in more than 10 studies, while 21 were used only once; 7/24 generic and 19/21 specific questionnaires were validated for epilepsy. The different domains considered in the 26 questionnaires specifically validated for epilepsy are listed. We classified questionnaires according to three aspects: validation, diffusion of use, and specificity of domains. Questionnaires covering all three aspects (WPSI, ESI-55, QOLIE-89, QOLIE-31, QOLIE-10, Liverpool Batteries) should be preferred when planning a QoL study in epilepsy. However, those covering only two aspects (SF-36, SEALS, EPSES, EOS, PESOS, QOLAS) could also be useful in selected situations or may become a first-choice instrument in the future, after more widespread use or complete validation. All the other instruments should at present be considered only for second choice.

Measuring the efficacy of antiepileptic drugs

Clinical trials of new antiepileptic drugs (AEDs) include regulatory studies aimed at demonstrating efficacy and reasonable safety, post-marketing open-open label studies and longer term outcome studies. Regulatory trials involve a carefully selected population of patients and are conducted under rigorously standardised conditions. Data from such studies cannot often be translated into clinical practice. Pragmatic post-marketing studies using flexible dosing schedules allow clinicians to better judge the utility of the new drug in a wider population of patients with epilepsy and decide the most appropriate dosing schedules. This paper discusses some of the issues surrounding the measurement of efficacy of new AEDs in both pre- and post-marketing phases of their development. All of the newer AEDs are initially used in patients with refractory partial seizures as adjunctive treatment. These trials are generally parallel-group studies although cross-over designs have been employed. The use of placebo-control is uncontroversial in this type of study. Efficacy endpoints are generally manipulations of seizure frequency on study drug compared to control. Global outcome measures and health related quality of life scores can also be used to measure efficacy. As the standard AEDs are associated with a high rate of seizure remission in patients who receive them as monotherapy, demonstration of superior efficacy of a new agent in a comparative trial will require large numbers of patients in a design that takes into account the natural history of treated epilepsy. Comparing investigational agents to a standard AED in an 'active-control' study with demonstration of equivalent efficacy would seem to be an acceptable way of assessing efficacy of new AEDs in this population. Some regulators, however, do not accept equivalence as proof of efficacy and insist on demonstration of superiority compared to a control. The use of placebo alone in the control group is ethically dubious. Several innovative study designs have, therefore, been used to satisfy regulatory requirements, while maintaining patient safety including withdrawal to monotherapy using high versus low dose comparators. Observational outcome studies provide the best opportunity of exploring the long-term utility of individual AEDs. Such studies largely follow standard clinical practice and need considerable time and resources. They can, however, yield valuable information about the effectiveness of AEDs in everyday clinical practice. Data from regulatory trials should be complemented by postmarketing studies and longer term studies of outcome to help clinicians decide the best way of utilising new AEDs and establishing their role in the therapeutic armamentarium.

Challenges in the clinical development of new antiepileptic drugs

The very nature of epilepsy makes the clinical development of new antiepileptic drugs a lengthy and costly process. The underlying disease mechanisms are largely unknown, reflecting the paucity of animal models that mirror the human condition. The risks of untreated epilepsy usually preclude the use of placebo as a control treatment except in patients receiving background medication. Thus, new AEDs must first display a treatment effect in patients with seizures known to be resistant to drug therapy, using study designs that are confounded by the potential pharmacodynamic and pharmacokinetic interactions associated with polytherapy. Moreover, the unpredictable nature of epilepsy often means lengthy clinical trials. Clinical development for antiepileptic drugs is inevitably more complex and time-consuming than for many other drugs. As a result the interval between product approval and loss of patent is often shorter. Creative methods of accelerating the development process without compromising the quality of research are needed.