Let's take a look at today's top stories in biotech and health care. Keep an eye out for Allergan (NYSE: AGN), Arena Pharmaceuticals (ARNA), and Bristol-Myers Squibb (BMY 0.17%)

Allergan looking to "upsize" to fight takeover bid
It's no secret that Allergan has been attempting to avoid a takeover by Valeant Pharmaceuticals (BHC 1.72%). And recent events such as a special meeting of Allergan shareholders to discuss Valeant's offer suggests that management may end up losing this fight before much longer. 

Even so, Allergan's CEO David Pyott isn't going down without a fight. In an interesting turn of events, Pyott announced yesterday that the company is looking at a "sizable" acquisition that could end Valeant's hostile takeover bid.

Although the details of Pyott's plan haven't been made public, Shire's (NASDAQ: SHPG) name popped up as a possible target. Shire is presently mired in its own acquisition talks with AbbVie that are starting to reach fever pitch. Overall, I think Allergan may be down to its last cards here and talk about acquiring a similarly sized company looks more like a Hail Mary than a viable strategy to avoid a takeover. 

Arena announces completion of increased Belviq sales force
Shares of Arena are up slightly in premarket this morning after announcing that its marketing partner Eisai has completed its planned increase of 200 additional sales reps for the duo's fat-fighting pill Belviq. This increase is part of a broader relaunch effort of the drug after it has repeatedly posted disappointing prescription and sales numbers, following its initial commercial launch last year.

With Orexigen Therapeutic's rival drug likely to reach the market later this year, Eisai's renewed marketing efforts are coming at a pivotal time in the drug's life cycle. Put simply, this may be the last major effort to push the drug as a treatment for chronic obesity, as it stands. If this effort fails to dramatically improve the drug's commercial performance, I think the companies will wait for a label expansion to be approved before using any more resources to try to increase sales. 

Bristol-Myers to submit nivolumab for regulatory approval as a melanoma treatment
Bristol-Myers announced this morning that its plans on filing a Biologics Licensing Application for its closely watched PD-1 inhibitor called nivolubmab in the third quarter, as a potential treatment for advanced melanoma that has previously been treated with Yervoy or a BRAF inhibitor regimen.. Bristol-Myers is also in the process of completing a rolling submission for the drug as a treatment for non-small cell lung cancer.

In its press release, Bristol-Myers proposed the trade name Opdivo, if nivolumab is granted approval. Bristol-Myers is also developing nivolumab as a potential treatment for renal cell carcinoma, head and neck cancer, glioblastoma and non-Hodgkin lymphoma. Shares are presently unchanged in response to this news.