US spending on prescription drugs rose just 2.3% last year to $30.7 billion, a significant drop on the 5.1% growth reported for the previous year, according to IMS Health.

In 2010, the volume of prescription medicines consumed in the US overall rose at historically low levels, due to factors including increased use of generics, loss of patent protection for major branded products and reduced levels of spending on new therapies, said Michael Kleinrock, director of research development at the IMS Institute for Healthcare Informatics, which produced the new data.

"Moreover, fewer patients visited physician offices and initiated new chronic therapy treatments last year - likely the result of the slower economy," he added.

The total volume of medicines consumed in oral or nasal form by US patients last year rose just 0.5%, which is a decline of nearly 0.3% per capita and results from lower or declining demand in nearly every major therapy area, says IMS. Consumption of medicines administered by injection or infusion increased 0.2%, representing a per capita decline of 0.6%.

The number of patients starting new treatments for chronic conditions declined 3.4 million, and the average patient copayment fell $0.20 to $10.73, mainly due to the increased use of generics. Commercial third-party insurance was used by patients to pay for 63% of dispensed prescriptions, down from 66% five years ago, and prescriptions filled under the federal Medicare prescription drug plan (Part D) or through federal/state Medicaid programme coverage represented 30% of all prescriptions last year, compared with 22% in 2006, the first year of Medicare Part D.

Examining trends in pricing, IMS reports that the average cost of oral or inhaled medicines, which made up 60% of overall US spending last year, declined 0.1% due to changes in price as well as in the mix of generics and branded products, while costs of medicines administered by injection or infusion, representing 28% of all spending, rose 5.7%. 

44 new branded products became available to US patients in 2010, 10 of which featured innovative mechanisms of action - these included a new oral therapy for multiple sclerosis, a monoclonal antibody for osteoporosis and bone metastases and a therapeutic vaccine for prostate cancer.

Last year also saw the launches of five orphan drugs and six New Chemical Entities (NCEs) using existing mechanisms,for the treatment of conditions including rheumatoid arthritis, prostate cancer and meningitis, says the study.

Average spending per new branded product (eg, available for 24 months or less) totaled $62 million last year, down from $114 million in 2006 and reflecting a shift in the mix of new products towards orphan drugs and medicines with the same mechanism of action as existing treatments, it notes. And while expenditures on branded drugs fell 0.7% last year, spending on branded and unbranded generics rose 4.5% and 21.7%, respectively.

Generics now account for 78% of all US retail prescriptions dispensed and, on average, more than 80% of a brand's prescription volume is replaced by generics within six months of patent loss, says IMS.

The report also finds that in the leading therapy areas, last year’s spending growth was largely driven by product lifecycle dynamics rather than price or volume. The top five therapy classes were: - oncologics, with spending of $22.3 billion; - respiratory agents on $19.3 billion; - lipid regulators at $18.7 billion; - antidiabetes drugs at $16.9 billion; - and antipsychotics on $16.1 billion.

Growth in spending among these classes ranged from 0.9% for lipid regulators to 12.5% for diabetes treatments, while total spending on oncology drugs grew just 3.5%, the lowest increase ever recorded for the therapy class, the firm reports.

The results for 2010 show that the UK healthcare landscape is shifting in significant ways, commented Mr Kleinrock. "Physicians and patients have more therapy options than ever, and yet spending on medicines is rising at historic lows with the impact of patent expiries and reduced patient activity,” he noted, while the long-term effect on patient health of fewer doctor office visits and new therapy starts is "unclear."