Governments and insurers around the world are wasting money on expensive “me-too” drugs that offer no substantial benefit over existing products, Canadian researchers reported in this week’s issue of the British Medical Journal.

Some 80 percent of the increase in British Columbia’s drugs bill from 1996 to 2003 was due to spending on newly patented versions of old medicines, and the same probably holds true in most developed countries, according to the report.

Steven Morgan and his colleagues at the University of British Columbia looked at 1,147 new drugs appraised in Canada between 1990 and 2003 and found only 5.9 percent of them met the regulatory criterion of being a breakthrough, defined as the first to treat a particular disease or providing a substantial improvement over existing products.

The balance of the newly patented drugs were not substantially better, so were classified as “me-too.” Yet these products accounted for 44 percent of drug use and 63 percent of expenditure in 2003.

The world’s 20 top-selling medicines include many newly patented versions of old drugs, the researchers note.

Long-established categories that are still generating pricey patented products include ACE inhibitors for blood pressure, Statins for High cholesterol, selective serotonin inhibitors for Depression and proton pump inhibitors for gastric acid complaints.

The researchers said AstraZeneca Plc’s best-selling heartburn and ulcer medicine Nexium, which is a derivative of its older drug Prilosec, was a classic “me-too” drug.

Breakthrough medicines, meanwhile, included Pfizer Inc. and Eisai Co Ltd’s Aricept for Alzheimer’s disease and Johnson & Johnson’s Remicade, they said.

Drug makers, including AstraZeneca, deny the charge that they sell follow-on medicines with no added value. The industry argues that progress in medicine is often incremental and new versions of products can bring significant benefits to patients.