Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Let's take a look at the top stories in biotech and health care this morning -- keep an eye out for Pluristem Therapeutics (PSTI -0.20%), Rigel Pharmaceuticals (RIGL -3.11%), and Sangamo Biosciences (SGMO -2.13%)

Pluristem heading higher on FDA approval of placental-based cell products manufacturing facility 
Pluristem looks to be in for a good day after receiving approval to manufacture its PLacental eXpanded cell products in its new commercial-scale cell manufacturing facility from the U.S. Food and Drug Administration, or FDA. This is the second regulatory approval for the company's 3D cell manufacturing process, having received approval in Germany last January. Shares of Pluristem are up over 6% in premarket on this news. 

Is this a company worth keeping tabs on? Personally, I am not a big fan of investing in stem cell companies, and think the technology still has a long way to go before it's investment worthy. So, while this is a step in the right direction, I think there are safer, more compelling investments in the biotech sector than Pluristem.

Rigel up on preclinical data for R118
Little known biotech Rigel Pharmaceuticals rallied over 10% yesterday and is showing continued in strength in premarket following the publication of preclinical data for its experimental peripheral artery disease, or PAD, treatment called R118. The company also announced that R118 has now entered an early stage trial, where it will be tested for safety signals and signs of efficacy. R118 is an orally bioavailable AMPK activator hypothesized to improve exercise performance and peripheral vascular flow in patients afflicted with PAD. Investors are excited about the treatment's prospects because PAD is a potentially large market, and Rigel's market cap is small at $358 million compared to R118's projected commercial prospects. 

Time to jump in? I would have to say no at the current time. Remember, R118 is only now entering the actual clinical testing phase of its life cycle, and there are ample opportunities for failure along the way. Moreover, Rigel's current valuation appears to be tightly linked to R118's clinical prospects. So, you may want to take a wait-and-see approach with Rigel.  

Did Sangamo just revolutionize HIV treatment?
Shares of Sangamo Biosciences are shooting higher this morning by 21% after news hit the Street that the company's zinc finger nuclease-based genome editing technology achieved functional control over HIV infections in six patients. While the data are still preliminary, this approach has a naturally occurring analogue that suggests it may ultimately succeed, namely the so-called delta 32 mutation in the CCR5 gene. Essentially, this mutation keeps HIV from entering T-cells in the first place, where it replicates and subsequently infects the rest of the immune system. Sangamo's treatment, called SB-728-T, mimics this mutation by genetically engineering T-cells to make them resistant to HIV infection. This exciting work was recently published in the New England Journal of Medicine

Should you jump on the bandwagon? Although this clinical result is promising--and even awe-inspiring in many ways, I can't honestly say that Sangamo represents a good investment at this stage. The company has a market cap topping $1 billion, and is essentially a developmental stage company. That said, you should keep tabs on Sangamo, especially as the company's interesting clinical pipeline progresses.