3 Humongous Health-Care Stocks This Week: Celgene Corporation (CELG), Celldex Therapeutics, Inc. (CLDX)

The Dow set an all-time high, but it still was up only 2% for the week. If you want returns to really get excited about, look no further than the health-care sector. Here are three stocks that churned out humongous gains this week.

Mad money?
Shares in Astex Pharmaceuticals, Inc. (NASDAQ:ASTX) soared this week by nearly 37%. This was a huge jump considering there was no major news. So what happened?

The one significant event this week related to Astex was that TheStreet.com upgraded the stock from “hold” to “buy.” However, that upgrade occurred on Monday, while shares didn’t really take off until Wednesday. Once the buying frenzy started, it didn’t stop. The stock continued to climb strongly through the end of the week.

Trading volume for each of the last three days of the week was around four times higher than normal. It could be lots of smaller investors with mad money to spend. My guess, though, is that some entity with deep pockets is buying Astex like crazy. I won’t be surprised if we find out later that a hedge fund or other large investor scooped up big chunks of the stock.

Less loss equals big gain
There wasn’t much mystery behind the major moves for stem cell company Osiris Therapeutics, Inc. (NASDAQ:OSIR) . Shares surged nearly 35% for the week after the company posted better-than-expected earnings results.

Osiris reported a net loss of $0.08 per share, compared with a $0.15-per-share gain in the same quarter of the prior year. However, analysts were expecting the loss to be much worse at $0.15 per share. Osiris also reported $3.1 million in revenue, down from $11 million in the same quarter for 2011. The big year-over-year difference stemmed from Sanofi SA (ADR) (NYSE:SNY)‘s cancellation of an agreement in early 2012.