certain compounds increases ozone production. Importantly, certain groups may be acutely susceptible to the effects of air pollution, and clinicians should advise them accordingly.

Over the past several years, Australians havebeen given access to several drugs which can be prescribedunder a taxpayer-funded scheme only if the patient has aspecific molecular disease target that predicts a good treatmentoutcome.The first such drug was trastuzumab for the treatment ofbreast cancer in women whose tumours over-express the HER2protein. This drug was supplied by the government fromDecember 2001 through a special program outside the Pharma-ceutical Benefits Scheme (PBS). Another drug, imatinib, was alsolisted on the PBS in December 2001 for use in the acceleratedand blast phases of chronic myeloid leukaemia, and in October2002 for use in the chronic phase of that disease. In December2004, gefitinib was listed for the treatment of non-small cellcarcinoma of the lung in patients with evidence of an activatingmutation in the epidermal growth factor receptor gene. Thesedrugs are likely to be harbingers of a stream of drugs in whichgenetic information about individuals or their tumours (whetherthey result from DNA or RNA sequence changes, or proteinalterations) will be used to maximise the efficacy of treatment.Funding the provision of new biological agents under the PBSwill present a major financial outlay. Though the number ofeligible patients may be small, the costs per patient are high (eg,more than $45 000 per patient per year for imatinib and morethan $50 000 per year for gefitinib and trastuzumab). The highcost of providing these drugs to relatively small numbers ofpatients will add to the cost of the PBS when annual growth ingovernment expenditure on pharmaceuticals averaged 10.5%between 1992–93 and 2002–03 (increasing from $1.883 billionto $5.121 billion).