Time to entry of generic medicines in Malaysia: implications for pharmaceutical cost containment

Abstract

Generic medicine availability is crucial for maintaining the Malaysian heavily subsidised public healthcare system, and for reducing rising national pharmaceutical expenditure. This paper analyses the time to entry of generic medicines following patent expiration on innovator drug products in Malaysia. This study utilised a robustly constructed dataset of 12 best-selling single-entity prescription drug products that experienced loss of patent protection and subsequent generic entry between January 2001 and December 2009. Time to entry was measured as the time lag between expiration dates of basic patent of the innovator active drug substances and marketing approval dates of the first generic equivalents. Patent data of the drug substances were sourced from Malaysian and international patent databases. Marketing approval data of both the innovator and generic drug products were sourced from the product registration databases of the Malaysian drug regulatory authority. A total of 154 (mean (M) = 12.83, standard deviation (SD) = 9.61) generic entries occurred during the data period for the entire 12 active drug substances. The mean time to entry (in days) following basic patent expiration was 396.92 (SD = 507.49). A significant difference was found between the hypothesised time to entry and the study mean time to entry. Time to generic entry in Malaysia is significantly delayed beyond the day following basic patent expiration of innovator product, thereby delaying the onset of generic competition with potential negative implications on pharmaceutical expenditure.