Now that activist investor Carl Ichan has taken a stake in Amgen (Nasdaq:AMGN), is the Thousand Oaks, Calif.-based biotech giant likely to be auctioned off to Big Pharma’s highest bidder?

Speculation is running high that the die has been cast, that Amgen will soon suffer the fate of other former Ichan targets, MedImmune and ImClone, and be gobbled up by a big drug maker.

Ichan has said that biotech companies need Big Pharma’s capital resources to capitalize on the market potential of their pipeline drugs, calling such link-ups, “a marriage made in heaven.”

The prospect of nuptials for Amgen also has been fueled by the other big names who also think the stock is a smoking deal.  A slew of high-profile players have taken positions in the company recently, among them HealthCor Management, an investment adviser to healthcare and life sciences hedge funds. Others include Ridgeback Capital, Sigma Capital Management Ascend Capital, Diamondback Capital, OZ Management and Moore Capital.

These big buys have helped boost the stock nearly 6% in the past month, outpacing the S&P, Nasdaq and the Biotech Index. But if a sale doesn’t materialize, is there still room for other investors to squeeze out a few bucks profit on Amgen? If the past is prologue, the answer is “maybe.”

Hedging is necessary here because of the results Ichan has achieved with other targets. In fact, the performance of the stocks in which he’s taken a stake was recently the subject of a study on activist campaigns by entrepreneurial investors and hedge funds.

The study’s authors reported a substantial positive runup – about 10% – upon Ichan announcing he had taken a position in the target firm.  After the first month, though, the picture becomes mixed — it turns out there was a big difference in the share-price performance between the approximately one-third of companies that were either taken private or acquired within the first 18 months and those that remained independent.

As expected, the acquired group enjoyed significant positive stock market returns. Investors who followed Ichan into the companies that remained independent weren’t so lucky. They lost a whopping 60% of their investment. Some say Ichan’s proposed changes to those companies could be the reason for the steep price declines. However, the study’s authors speculate that as a result of fending off Ichan, the companies didn’t have to make the changes he wanted, and that’s the reason they went south.

You can count on Ichan pressuring Amgen’s management and board to make changes.  Kevin Sharer, CEO of Amgen, might be in Ichan’s sights. Sharer, who has been CEO since 2000 and was made chairman a year later, has been highly criticized for presiding over a number of company debacles during his reign. The issues plaguing Amgen have are reflected in the fact that the company’s share price has remained stagnant since Sharer took over. Fortunately for him, Sharer is 63 years old and probably would be pleased to take a buyout package and ride off into the sunset.

So what will it be for Amgen, a takeover by a member of Big Pharma or a long-drawn out effort to resurrect the once high-flier of biotechnology? The first option could put some quick money in investor pockets. The second — who knows?