Trend of sales revenue by year for top selling cancer drugs in the US and the effect of loss of market exclusivity

Biosimilars and generics have led to reduced cancer drug prices. The effect of biosimilar or generic drug competition on drug manufacturer revenue has not been previously described. In this study, the majority of top selling cancer drugs had a greater than 50 % decline in sales revenue within 2 years of generic or biosimilar market entry, reflecting both the decline in market share and reduction in unit drug price. This results in important drug manufacturer incentives, which may shape clinical trial agendas. The market structure incentives are unique for pharmaceutical companies due to the relatively short and limited duration of profitability. Policy changes such as patent reform leading to shorter duration of exclusivity may lead to greater incentive to expand low value indications in oncology.