In Australia, sales of the leading 20 cancer drugs grew 30% a year on average during 2003-8, reaching US$545 million in the latter year and, despite slower growth over the following 10 years, will reach US$1 billion by 2018, say new forecasts.

Molecular targeted therapies are the leading class of cancer treatments in Australia, with sales of such products in the top 20 totalling $320 million. They have accounted for most of the overall growth in the market during 2005-8, driven by the uptake of high-priced products and a lack of generic competition, according to the new study, from Datamonitor. The report expects these products to continue driving market growth in Australia over the next 10 years, with sales set to reach $750 million in 2018, reflecting the market’s potential for increased uptake in existing indications and further expansion of indications.

The other two cancer product classes - therapies and antihormonal treatments – predate the molecular targeted therapies. They are associated with varying levels of toxicity and Datamonitor believes that, combined, their sales will reach just $200 million in 2018. It is increasingly widely thought that tumour-targeted agents “could become some of the most powerful tools in the fight against cancer, due to their ability to discriminate between cancerous cells and other healthy cell types,” says Lisette Oversteegen, senior healthcare analyst at Datamonitor.

The top-selling cancer drug in Australia in 2008 was Herceptin (trastuzumab), Roche’s molecular targeted therapy for patients with human epidermal growth factor receptor 2 (HER-2)-positive breast cancer. The product’s sales reached $120 million in the year, having grown by an annual average of 61% since 2005, and it has exceptional reimbursement status both within and outside Australia’s Pharmaceutical Benefits Scheme (PBS).

Herceptin’s sales will continue growing in the near future, due to its widespread use among breast cancer patients and an approval in HER-2 gastric cancer, but its revenues will be “somewhat dampened” by uptake of GlaxoSmithKline’s Tykerb/Tyverb (lapatinib), which is also a molecular targeted treatment but has the advantage of oral administration, while Herceptin is available as an intravenous drug only, comments Ms Oversteegen. Furthermore, continued development of Tykerb/Tyverb “is expected to result in an approval and PBS listing for first-line and adjuvant treatment, placing it in direct competition with Herceptin,” she notes.

Another targeted cancer therapy from Roche is Avastin (bevacizumab), but while this product’s 2008 sales reached $2.5 billion in the USA alone, its uptake in Australia has so far been slow, due to a lack of reimbursement for three of its four indications, resulting in sales of just under $8 million. Avastin’s only PBS listing so far came in mid-2009, for the first-line treatment of metastatic colorectal cancer, with an earlier submission having been rejected over concerns that the drug would be used off-label and would therefore have an unacceptably high cost-effectiveness ratio.

However, Australia’s Therapeutic Goods Administration (TGA) has also approved Avastin for the treatment of breast cancer, non-small-cell lung cancer and renal cell carcinoma, and the drug’s sales in the country will reach $190 million by 2018, due to fast indication expansion, forecasts Datamonitor. Assuming that the Pharmaceutical Benefits Advisory Committee (PBAC) does not create too many hurdles on its path to reimbursement for these additional indications, Avastin should become Australia’s second-highest-selling cancer drug by 2018, behind Roche’s Rituxan/MabThera (rituximab), whose revenues should reach $225 million by that date, according to Ms Oversteegen.