Evaluating medicines: let’s use all the evidence

To the Editor: With the proposed formation of the Australia New Zealand Therapeutic Products Authority (ANZTPA), the recent viewpoint article1 and accompanying editorial2 on systems of evaluating medicines were timely. Both reports provided interesting comments on existing systems and proposals for improving these in the future. However, I would like to comment on some omissions and errors in these articles.

In their viewpoint article, Kelman et al stated that “there are as yet no overseas examples of ‘routine’ medicines monitoring”.1 This is not correct. The New Zealand Intensive Medicines Monitoring Programme (IMMP) has been undertaking routine monitoring of selected medicines since 1977. The IMMP collects nationwide prescription data to form cohorts of patients who are subsequently monitored for adverse events.3 These patient cohorts provide accurate denominator populations, which, as noted by Kelman et al,1 is important for risk quantification by measurement of incidence.

The IMMP uses prescription-event monitoring (PEM) methods to perform active postmarketing surveillance of new medicines in New Zealand, and has been successful in identifying numerous new signals of adverse drug reactions and in quantifying risk.4 The IMMP has developed ways of enhancing PEM methodology by linking records with national morbidity and mortality databases.3 This methodology was recently successfully applied in a study of the safety and usage of atypical antipsychotic medicines in a nationwide paediatric population.5

In their editorial, Stanley and Meslin commented that none of the health care data linkage systems in England, Scotland, the United States or Canada “are nationwide or have the routine ability to link health care records with drug prescription data”.2 As described above, the IMMP has both these abilities. It was somewhat surprising that, although discussions regarding pharmacovigilance in the ANZTPA are now well underway, current systems in New Zealand were not mentioned in either of these Journal articles.

I would encourage Australia to develop pharmacovigilance systems similar to those established in New Zealand. Of course, these will need to be adequately funded to achieve the expected outcomes. The formation of the ANZTPA is a great opportunity to improve pharmacovigilance in both countries.