Expensive new drugs treating increasing numbers of patients could drive US drug spending by as much as 15% a year to 2013, say new forecasts.

At this accelerated rate, oncology treatments will likely become the second or third-largest category in terms of driving US drug spending by 2015, after diabetes and central nervous system (CNS) therapies, according to the latest annual Drug Trend Report produced by leading pharmacy benefit manager (PBM) Medco Health Solutions.

Even though the incidence of some types of cancers may be decreasing, the overall number of cancers reported in an ageing population has increased significantly because of better detection and, with advanced treatment, the number of US cancer survivors is expected to increase from 13.8 million in 2010 to 18 million by 2020, a rise of more than 30%, says Medco.

Spending on oncology specialty drugs increased 21.2% during 2010, primarily as a result of unit cost increases of 13.7%, the report notes.

'New cancer drugs reaching the market are expected to double during the next several years," says Glen Stettin, Medco's chief medical officer. "Early diagnosis, evidence-based treatment and enhanced coordinated care have essential turned some forms of the condition into chronic illnesses that can be managed longer-term. Continued innovation, including companion diagnostic or pharmacogenomic testing, can help ensure the right person is getting the right drug at the proper dose and reduce waste," he added.

The use of many newly-introduced specialty drugs helped drive oncology drug price inflation to 11.5% in 2010, Medco reports. Increased prescribing of new treatments such as Celgene's Revlimid (lenalidomide) for multiple myeloma and Novartis' Gleevec (imatinib mesylate) for chronic myeloid leukaemia and gastrointestinal stromal tumours drove sharp increases in spending, it says, and notes that the Journal of the National Cancer Institute has reported that more than 90% of anticancer drugs approved since 2004 cost more than $20,000 for a 12-week course of therapy.

Many of these newer treatments are oral medications or can be self-administered, changing the dynamic of cancer care delivery towards the home rather than the physician's office or infusion centre, and this dynamic shows no sign of abating, says Medco.

"It’s an exciting time in the area of cancer treatment, but as these new, targeted treatments come to market it is vital to ensure that each patient and caregiver understands the importance of adherence and the detailed dosing instructions associated with them,” emphasises Milayna Subar, national practice leader for the Medco Oncology Therapeutic Resource Center. 

"Helping patients manage the unique needs of their disease across the continuum of care with specialists and a personalised medicine programme will help to improve outcomes for the patient and could help to manage down the projected drug trend of 15%-17% for these new specialty medications," Dr Subar adds.