With the SPDR S&P Biotech Index up 38% over the trailing-12-month period, it's evident that investment dollars are willingly flowing into the biotech sector. Keeping that in mind, let's have a look at some of the rulings, studies, and companies that made waves in the sector last week.

As always, we'll lead off with the feel-good stories for the week -- and nothing made shareholders of Astex Pharmaceuticals (UNKNOWN:ASTX.DL) feel better than the announcement on Thursday that Japan's Otsuka Holdings will buy Astex for $804 million, or $8.50 per share. The price of the deal represents a 30% premium from where Astex began the week. With this purchase, Otsuka gains access to FDA-approved myelodysplastic syndrome drug Dacogen, as well as a promising pipeline of cancer drugs, including SGI-110 which delivered positive top-line results in a mid-stage acute myeloid leukemia trial last week. In my opinion, I'd say Otsuka is getting an absolute steal of a deal on Astex given its strong cash position, multiple big pharmaceutical partnerships, and the recent favorable results in its pipeline. The market may feel this way as well with Astex current finishing the week slightly ahead of its offer price.

The remaining noteworthy stories this week were all related in one way or another to a positive or negative reaction to clinical-stage data.

In the plus column, Rockwell Medical (NASDAQ:RMTI) even trumped Astex, rising a clean 50% this week following positive late-stage study results of soluble ferric phosphate, or SFP, an iron replacement therapy for chronic kidney disease patients that are on dialysis. The study demonstrated that SFP met both its primary endpoint (statistically significant change in hemoglobin levels from the start to end of the study) and secondary endpoints (maintenance of hemoglobin, reticulocyte hemoglobin, and increase in serum iron in pre-to-post treatment without an increase in ferritin). With a good shot of becoming the go-to iron replacement therapy thanks to its superior safety results, Rockwell shareholders certainly have something to cheer about. Expect Rockwell to file for a new drug application within the next couple of months.

Also delivering shareholder-pleasing clinical data this week was the chronic obstructive pulmonary disease (COPD) "little giant" Theravance (UNKNOWN:THRX.DL). On Wednesday, Theravance announced that its phase 2b trial involving in-house and wholly owned drug TD-4208, a long-acting muscarinic antagonist, met both its primary and secondary endpoints in the study which included a change in FEV1 (forced expiratory volume in one second) by day seven, and demonstrated the potential of being a once-daily treatment . To add, on Friday the FDA posted its briefing documents for Anoro Ellipta, the inhaled COPD drug developed in collaboration with GlaxoSmithKline (NYSE:GSK) that's currently under review by the FDA. The briefing documents alluded to strong efficacy at both doses that the companies are trying to gain new drug approval for. Needless to say with the FDA panel meeting scheduled for Tuesday, current shareholders have to be holding their head high.

But, it wasn't all peaches and cream for the biotech sector -- even GlaxoSmithKine!

On Thursday, Glaxo announced that the first of two primary co-endpoints in its melanoma cancer vaccine immunotherapy trial involving MAGE-A3 failed to hit the mark. The first co-primary endpoint was to extend disease-free survival in patients, which it failed to do. The independent data monitoring committee, however, is letting Glaxo continue with its ongoing late-stage study on its second co-primary endpoint which is designed to assess the effect of the vaccine on genetically predisposed patients who may benefit from the therapy. Not all hope is lost, but it's a sizable blow for a once promising late-stage cancer vaccine.

Finally, this week's disaster du jour goes to small-cap biotech Cytokinetics (NASDAQ:CYTK), which announced underwhelming mid-stage top-line results for its acute heart failure drug omecamtiv mecarbil. The drug, which Cytokinetics has collaborated with Amgen to develop, failed to meet its primary endpoint of a statistical difference in improving dyspnea system response in patients -- or in other words, their ability to breathe easier. Like Glaxo, not all hope is lost as Amgen just boosted its collaborative pact on the drug in June with Cytokinetics so it must've seen something it liked. However, with the interim data blatantly underwhelming, Cytokinetics' shares fell about 18% this week.