Speaking of cliffs …

London-based EvaluatePharma estimates there are $290 billion of sales at risk from patent expirations between this year and 2018. In 2013, patents will expire on drugs that currently have sales of $29 billion annually, more than 70% of which will be lost to generics; that’s less than half 2012’s total.

Anthony Raeside, head of research for EvaluatePharma, estimates the pharmaceutical industry has invested $1.1T in the last decade on research and development to try to offset the revenue shortfalls and tumbling of share prices resulting from reaching a patent cliff.

Approximately 120 drugs will reach patent expiry in 2013, topped by Eli Lilly's anxiety and anti-depression drug Cymbalta, which last year generated $4.9 billion in sales for the company. To see the top 15 at risk, read further.