Anyone looking for home runs doesn't necessarily have to watch the World Series. Several health-care stocks knocked the ball out of the park over the past few days. Here are three of the most humongous winners this week.

RAYOS of hope
Horizon Pharma
(HZNP) tops our list. Shares of the specialty pharmaceutical company soared almost 21% this week.

Two stories made the news for Horizon over the past several days. On Monday, the company announced that clinical data for its delayed-release prednisone tablet RAYOS would be presented at the American College of Rheumatology/Association of Rheumatology Health Professionals meeting that starts this weekend and extends into next week. Horizon launched RAYOS earlier this year but recorded less than $1 million in sales of the drug during the second quarter.

The other news for Horizon involved a new lawsuit against Par Pharmaceuticals. Par is attempting to move forward with a generic version of RAYOS, an action that Horizon thinks violates its patents for the drug. The two companies settled a patent infringement lawsuit involving Horizon's drug DUEXIS in August.

Stopping for good
Putting a stop to a clinical study early isn't a good thing in many cases. However, for Medivation (MDVN), doing so was a really good thing. Shares jumped more than 18% after the company stopped a phase 3 study of Xtandi.

Medivation's independent committee monitoring the study recommended halting the trial after results showed Xtandi to be clearly effective in improving overall survival in patients with advanced prostate cancer compared with patients taking placebo. Those patients taking placebo were switched to Xtandi. 

Medication and its partner Astellas now plan to move forward with a regulatory submission in early 2014. Xtandi received U.S. Food and Drug Administration approval last year as a second-line treatment for metastatic castration-resistant prostate cancer.

The latest news could propel Medivation into position to steal market share away from Johnson & Johnson's (JNJ -1.15%) Zytiga. J&J made $464 million from the drug in the third quarter, up 75% year over year. Xtandi generated sales of $82.4 million in the second quarter, but results haven't been announced yet for the third quarter. 

Less anemic
AMAG Pharmaceuticals
(AMAG) reported its third-quarter results on Wednesday. Shares climbed nearly 15% higher for the week on better-than-expected numbers.

Record-high sales for iron deficiency anemia drug Feraheme powered AMAG to revenue of $21.6 million, up 22% year over year. AMAG reported a net loss of $145,000, or $0.01 per share. That reflected a considerably improvement from the $0.19-per-share loss in the third quarter of 2012 and also surpassed the average analysts' estimate of a $0.12 per share loss.

The company hopes to gain FDA approval for a label expansion of Feraheme to treat adults with chronic kidney disease suffering from iron deficiency anemia with a history of unsuccessful oral iron therapy. The FDA announced a delay of the review last week and now expects to reach a decision by Jan. 21. 

Nearly a homer
It seems only fitting to also mention Organovo (ONVO -1.19%). As in baseball, some hits that appear to be going out of the park end up falling short. At one point on Thursday, Organovo's shares were up 25% for the week. However, much of that gain went away on Friday. Organovo ended the week up by almost 11% -- solid, but not spectacular enough to make our top three.

Organovo could be at the cusp of exciting breakthroughs in 3-D bioprinting of human tissues. My fellow Fool Maxx Chatsko sees several opportunities for the company. Improving pharmaceutical research using 3-D bioprinting could be just around the corner, with even bigger advances in the years to come.