Let's take a look at today's top stories in biotech and health care. Keep an eye out for Geron Corporation (NASDAQ:GERN) and Arena Pharmaceuticals (NASDAQ:ARNA)

Geron is soaring this morning on clinical update
Shares of clinical-stage biotech Geron are up over 30% in premarket this morning after the company announced that a partial clinical hold for its experimental myelofibrosis treatment called imetelstat has been lifted by the Food and Drug Administration. In March, the FDA placed a clinical hold on imetelstat after patients receiving the treatment exhibited signals for an increased risk of liver toxicity. Dr. Ayalew Tefferi of the Mayo Clinic has been providing additional safety data to the FDA since the hold was put into place, leading to today's partial release.

What's key to understand is that the FDA still has a clinical hold on imetelstat as a treatment for essential thrombocythemia and multiple myeloma. Moreover, Geron cannot initiate new clinical trials with the drug until the full hold is released.

I think today's news is a step in the right direction, but it remains to be seen if the FDA will release the hold for these other indications. It's also important to understand that the required laboratory studies will take some time to complete, so you shouldn't expect the full hold to be lifted anytime soon. As such, investors with a long term outlook might want to stay on the sidelines for the time being, especially since the bulk of Geron's value is directly tied to imetelstat.      

Arena could be in for a big day
Shares of anti-obesity pill maker Arena Pharmaceuticals gained over 4% in after hours trading yesterday following an interview with CEO Jack Lief on CNBC. Investors are apparently intrigued by his comments about a recent uptick in Belviq prescriptions, as well as his lack of commentary regarding a possible buyout by marketing partner Eisai. Adding fuel to the fire, Orexigen's competing drug Contrave had its regulatory review extended by three months yesterday, giving Belviq at least another quarter before it will face increased competition. 

While improving Belviq sales and a regulatory delay for a competing drug are good fundamental reasons to dig deeper in this mid-cap biotech, I think the buyout rumor simply doesn't have legs for a couple of reasons. We've heard this same rumor multiple times since Belviq's approval, and it has never panned out. And Belviq's sales as a treatment for chronic obesity have been lackluster, giving Eisai (in my opinion) little reason to make an offer. In sum, you should focus on Arena's underlying business -- and not potential buyout rumors -- when considering an investment.