Let's take a look at today's top stories in biotech and health care. Keep an eye out for Celgene Corporation (CELG), Mylan (MYL), and Exelixis (EXEL 2.10%). 

Mylan up on possible takeover of rival Swedish Pharma 
Shares of drugmaker Mylan are up over 11% in premarket this morning on two pieces of news. First and foremost, Mylan is reported to be considering putting in a tender offer for the Swedish generic and specialty drugmaker Meda (NASDAQOTH: MDABF). Meda presently has a market cap of $4.5 billion, per yesterday's close. So, a tender offer would probably come in north of $5 billion, given that Mylan would likely need to pay a premium to acquire the drugmaker. Mylan would acquire treatments for rheumatoid arthritis, women's health and respiratory disorders that saw sales of about $2 billion in 2013, if the two companies reach an agreement. According to Meda's Chairman Bert Ake Eriksson, the companies are in discussions about a possible merger. So, stay tuned!

Mylan sues Celgene over access to blockbuster drug samples
In a separate announcement, Mylan said it is suing Celgene over allegedly illegal actions the company is taking to keep generic versions of Revlimid and Thalomid off the market. Specifically, Celgene is accused of using federal limits on the distribution of the two blockbuster drugs to limit supply to companies seeking to perform "bioequivalence" testing. Mylan is therefore trying to force Celgene to sell them enough of the drugs to carry out the necessary tests. Celgene believes both drugs are protected from generic versions within the U.S. by either regulatory approvals or patents for roughly the next decade. What's key to remember is that generic drugmakers have been trying to gain access to Celgene's best selling drugs, without much luck so far. As perhaps a testament to the growing investor apathy over this ongoing saga, Celgene's shares have yet to react to the lawsuit in premarket trading. 

Piper says time to buy Exelixis
Despite shares of Exelixis being a near free fall after announcing that they would continue a late-stage trial for their castration-resistant prostate cancer drug Cometriq last month, Piper Jaffray said this morning that the stock is now a "buy," placing an $11 price target on the stock. Shares of Exelixis have fallen over 56% since the late-stage study for their prostate cancer treatment wasn't halted early for efficacy last week. While this drop may seem unusual in light of the fact that the trial hasn't actually failed, investors are concerned that Cometriq simply won't be able to compete with rival prostate cancer therapies such as Johnson & Johnson's (JNJ 0.45%) Zytiga, among others, without being able to claim at least a similar level of effectiveness. As a refresher, Zytiga's pivotal clinical study was halted early for efficacy and the drug has gone on to gain the lion's share of the prostate cancer market, since being approved in 2011. Exelixis shares are up over 3% in premarket following this upgrade.