Generic atypical antipsychotic drugs in Belgium

As a result, the availability of generic atypical antipsychotic (AAPs) medicines should be particularly welcomed by authorities. This is because worldwide sales of AAPs were over US$5 billion per year in the early 2000s, reaching US$14.6 billion in the US alone in 2009. In addition, medicines are the backbone of managing patients with schizophrenia and bipolar disease. However, there are certain classes of medicines where it may be difficult for the authorities to introduce multiple demand-side measures to influence future physician prescribing. This includes AAP drugs where it is recognized by both clinicians and authorities that the management of schizophrenia is complex and pharmacological treatments should to be tailored to individual patients. This is due to differences in their side effect profiles, as well as inter-patient variability in their effectiveness.

Consequently, the objectives of this [1] and similar studies in other European countries and regions were to assess changes in risperidone utilization before and after oral generics were reimbursed, as well as changes in overall expenditure. Subsequently, the findings from the various studies were to be utilized to provide future guidance to authorities. All studies, including this study, used a retrospective observational interrupted time series design. The principal data source for this study was Pharmanet, which contains all reimbursed medicines dispensed in public pharmacies in Belgium.

As expected, with no general demand-side measures in Belgium to promote the preferential prescribing of risperidone versus other AAPs, there was no increase in the utilization of oral risperidone versus other AAPs post generics. If anything a continuing decline in its use, decreasing from 28% total AAPs in early 2006 to 17% by August 2011 (DDD basis) was observed, which bordered on significance. This decline was perhaps due to issues such as side effects of risperidone versus newer antipsychotic medicines. Similar patterns were seen among other European countries including Austria, Ireland, Scotland, Spain (Catalonia) and Sweden. Having said this, the tightening of the regulations surrounding the reimbursement of long-acting risperidone injections (LARIs) in July 2012 helped to reduce its subsequent utilization in Belgium.

Both originator and generic oral risperidone were prescribed in Belgium post generics, with the originator reducing its price to compete. Generic risperidone was 59% below pre-patent loss prices by the end of the study.

These various results suggest that authorities cannot rely on a ‘spill over’ of learning from other disease areas to affect changes in physician prescribing habits in different classes post generics, especially where treatment decisions are complex. Specific measures are needed to encourage the prescribing of generic risperidone where appropriate. However, based on these various studies, the influence of such measures are likely to be limited due to the complexity of the disease area. Such demand-side measures may also be difficult to implement in patients with schizophrenia given the need to tailor treatments for this patient population. Consequently, authorities may need to wait until more AAPs lose their patients before it is possible to realize considerable savings. This is already happening in Europe.

Conflict of interest
The authors of the research paper [1] declared that there were no conflicts of interest.

Abstracted by Dr Brian Godman, member of International Editorial Advisory Board, GaBI Journal.

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References
1.   Godman B, De Bruyn K, Miranda J, Raschi E, Bennie M, Barbui C, et al. Generic atypical antipsychotic drugs in Belgium: their influence and implications. J Comp Eff Res. 2013;2(6):551-61.

Source: www.gabionline.net