Monotherapy trials in antiepileptic drugs: are modified "presurgical studies" a way out of the dilemma?

Monotherapy trials in epilepsy are confronted with a dilemma: either they are in conflict with ethical requirements, or they are scientifically not meaningful. Monotherapy trials, which are performed as controlled studies randomizing patients to ineffective (pseudo)placebo treatment, are incompatible with the Helsinki Declaration. On the other hand, equivalence or noninferiority studies using an active-control design do not permit valid conclusions on the efficacy of the test drug. Therefore, they do not fulfill scientific requirements for trials on new drugs. As an alternative approach, a monotherapy trial design for epilepsy patients undergoing presurgical evaluation was outlined. During presurgical evaluation, antiepileptic drugs are routinely tapered down for seizure recording. This situation is used for a placebo-controlled short-term monotherapy trial. Four trials according to this design have been completed so far. Recently, several points of concern have been raised against this design, especially for matters of ethics and external validity. In the present article, these objections are outlined and discussed. In the proposed modification the randomization and the titration of the test drug or control begins prior to the presurgical investigations. The advantages are: the test drug does not have to be titrated quickly, pure monotherapy conditions are achieved, and the subjects do not have to experience more seizures than are required for the presurgical evaluation.