A Comparison of New Drug Availability in Canada and the United States and Potential Therapeutic Implications of Differences

Authors: 
Joel Lexchin
Research Summary: 

Background
Claims are made that new valuable drugs are not available in Canada at the time that they are marketed in the United States. This study uses a convenience sample of new drugs marketed in the United States and determines how many of these products are initially unavailable in Canada and their therapeutic value.

Methods
Issues of the Canadian edition of The Medical Letter from May 12, 2003 to June 21, 2004 were hand searched for evaluations of new drugs and the following information was recorded: indication, availability in Canada and conclusions about therapeutic value. For drugs not available in Canada two clinical pharmacologists rated the therapeutic value of the products and the type of FDA review (standard or priority) was recorded. A database from the Therapeutic Products Directorate was searched to see if any of the drugs initially unavailable were subsequently marketed.

Results
Thirty-two of 37 drugs were not available in Canada. Between 9 and 11 of these products were rated as offering moderate to significant therapeutic gains. Twelve of the 32 drugs eventually were marketed in Canada.

Interpretation
Although the majority of new drugs marketed in the United States but not available in Canada do not offer any therapeutic advantage, between about a quarter and a third of may offer moderate to significant therapeutic gains. The reasons why these drugs are unavailable and how much their absence affects the treatment Canadians receive should be the subject of future research.