The glittering debuts of blockbuster drugs have been few and far between in recent years. And big pharmaceutical companies have increasingly decided to buy new drugs or entire biotech companies instead of pouring additional billions to get something out of their research pipeline.

The most recent example is an offer today by Roche, the Swiss drug giant, to buy out the rest of Genentech, the California biotech company (ticker symbol DNA—how cool is that?), for $43.7 billion.

The offer is a sharp shift in strategy by Roche, which has previously kept an arm's length distance from its investments. Roche owns 56 percent of Genentech.

Franz Humer, the chairman of Roche, said the two companies had collaborated for more than 20 years, but that it was time to put the partnership "on a new level."

"We are absolutely convinced that it is in the interest of both parties that we acquire the 100 percent and then structure it in a way that strengthens both sides of the operation."

Roche is offering $89 a share, which represents a premium of just 9 percent over Genentech's closing stock price on Friday.

Analysts at Cazenove said that Roche will have to increase its offers. "We would expect Roche will have to make a significantly higher offer if it is to acquire Genentech," they wrote in a research note.

Indeed, the average premium for recent pharmaceutical deals is 63 percent, notes Reuters, citing Credit Suisse research.