For the first time, cancer treatments accounted for 5% of overall drug spending in the first half of 2009, said Medco Health Solutions in a press release last week. The drugs could soon become the biggest contributor to specialty-pharmacy spending, according to the release. Spending on specialty oncology drugs increased 15.1% last year, and the products are the third-largest contributors to growth in specialty-drug spending after medications for autoimmune conditions and for multiple sclerosis.

Medco expects worldwide sales of oncology medications to total $80 billion by 2012, partly because the medications can cost tens of thousands of dollars per course of therapy. Nearly all of the cancer drugs that received US Food and Drug Administration approval in the past four years have cost more than $20,000 for a 12-week course of therapy, according to the press release. Some individual treatments can cost $10,000 per month. Oncology drugs are projected to account for 9% of all prescription pharmaceutical spending growth between 2009 and 2011.

In addition, a pipeline of targeted products that cause fewer side effects than traditional chemotherapy will likely contribute to increased sales. More than 800 cancer treatments are now being investigated. Many oncology agents in late-stage clinical development and several that are expected to receive approval in 2010 or 2011 will likely affect specialty-drug spending, according to the press release. Several new treatments for breast cancer could gain regulatory approval, including AstraZeneca’s (London) vandetanib, Amgen’s (Thousand Oaks, CA) motesanib, and GlaxoSmithKline’s (London) pazopanib.

Together, oral oncology drugs and the biopharmaceutical industry’s injectable monoclonal antibodies spur a great deal of drug spending, according to the press release. These products will likely continue to promote drug spending as existing treatments gain additional approvals and new drugs are marketed.

Early detection and effective, well-tolerated medications are enabling some patients to treat their cancers as if they were chronic diseases. Cancer patients now are living longer than they did a generation ago. The press release cited American Cancer Society data showing that the five-year relative survival rate for all cancers combined reached 66% between 1996 and 2004, an increase from a rate of 50% between 1975 and 1977.

“Targeted cancer therapies have dramatically reshaped oncology and greatly benefited cancer patients,” said Robert S. Epstein, Medco’s chief medical officer, in the press release. “The newer cancer drugs improve survival rates since they target what fuels the cancer’s growth. As some may extend life, they may be used for longer periods of time and improve quality of life for millions of patients. Due to the higher costs of these treatments, however, proper selection and dosing is extremely important.”

Besides oncology drugs themselves, supportive-care therapies that help manage the side effects of other cancer treatments account for a large proportion of cancer-related drug costs. Examples of supportive-care therapies include drugs to combat osteoporosis (which can result from breast-cancer treatments) and drugs to reduce the side effects of chemotherapy and radiation treatments.

See related PharmTech articles:

Cancer Drug Delivery on Homing Device (blog post)

Global Agreement for Cancer Treatment (PharmTech)