At the same time, the availability of generic competition can mean considerable savings for consumers.

Much of the problem is attributable to generic competition.

But just the credible threat of generic competition is enough to get manufacturers to lower their prices.

They said their estimates were based on conservative assumptions about when specific drugs would be open to generic competition.

Patents enable drug companies to market their products, free from generic competition, for a set period of time.

Before the generic competition started, sales had reached more than $1 billion a year, large for a cancer drug.

The patent would protect Fosamax from generic competition until 2018.

Before its first generic competition appeared in 1987, sales were more than $300 million annually.

For drug companies, patents and the protections that they bring from generic competition are critical.

Yet little attention has been paid to how delays in generic competition are driving up drug costs.