Post-registration studies for the evaluation of antihypertensive drugs.

Abstract

The full public health benefi t of new medicines is often only partially documented in the literature because of a lack of appropriate information. Much of this information is compiled after the drug is registered and has been available on the market for a large number of years. Such post-registration studies describe parameters of real-life clinical practice such as the treated population, conditions of treatment initiation, treatment duration, adherence, associated benefi ts/risks as well as the impact on treatment strategies, healthcare procedures and on public health and importantly morbidity and mortality (1) assessed in many ways. In France, it is currently carried out by the National Health Authority, by assigning a level of improvement in actual benefi t (IAB) (2). IAB is based on two parameters – effi cacy and safety of the product – in a defi ned target population, compared with one or more other drugs with similar indications, or within a similar therapeutic strategy. What role do post-registration studies play in the long-term risk and benefi t assessment of drugs, and what conditions and methodologies could be used for such assessment? In order to improve our knowledge on appropriate benefi ts and relevant risks, a number of questions may be raised, such as e.g. what study procedures to follow in monitoring studies carried out after a drug has been authorized. How can health authorities establish relevant guidelines and a methodological basis for specifi cations; which purposes should be addressed; and which methodologies are relevant in terms of design and execution? Epidemiological observational monitoring of antihypertensive drugs are now well established, and applied to assessment of non-cardiovascular outcomes, extended therapeutic effects adverse events profi les, therapeutic benefi ts in special populations, relative added value with respect to available treatments as well as public health benefi t in a regional and global perspective (Table I). The current Blood Pressure Drug Therapeutic Issue includes three studies, which have evaluated the extended effi cacy and safety of antihypertensive treatment regimens in multi-center open settings (3,4,5). The paper by Liou and coworkers (3) evaluated a large cohort of Taiwanese hypertensive patients treated with valsartan alone or in combination with other antihypertensive drugs. In this setting, they report that valsartan monotherapy was well tolerated, and that higher doses as well as combination therapy provided added benefi ts to the lower dose range and monotherapy, respectively. The combination of metoprolol and amlodipine in two dose levels was evaluated by Delvi et al. (4) in an Indian cohort of patients with mild to moderate hypertension. Responder and control rates were high with both fi xed dose combinations and provided clinically meaningful reductions in blood pressure Blood Pressure, 2011; 20 (Suppl 2): 3–4