NxStage Medical Inc. (NSDQ:NXTM) continues to reward Deerfield Capital, as the New York-based moved to lock in profits by selling a portion of its stake in the home hemodialysis company.

The open-market transactions, completed between Dec. 3 and Dec. 15, generated more than $2.7 million in gross proceeds. The stock fetched an average of about $7.49 a share, or about three times its price as of late March, when Deerfield was snapping up NxStage shares by the armful.

In all, Deerfield purchased 755,000 shares over a six-week span last winter while NxStage was floundering between $2.12 to $3.57 a share. But the bulk of the buying likely occurred during a two-day spike in trading volume ending March 25, when more than 1 million shares changed hands and the stock closed at $2.48.

Coupled with stock sales earlier in the month that took in more than $1.5 million, Deerfield has already made back that stake, and then some, and is now well above water with its overall investment in the Lawrence, Mass.-based manufacturer of portable dialysis equipment. The December sales take hedge fund’s total take from NxStage to more than $5.2 million since mid-June, when Deerfield shed 27,078 shares at $5.96 each for a tidy $161,400.

Deerfield, which invests solely in healthcare and biotech companies, owns just over 4.4 million NxStage shares worth about $33 million in its current trading range. The hedge fund has spent a total of around $20 million buying into NxStage, including $6 million in a June, 2008, private placement priced at $4.50 a share and about $10 million for 950,000 shares in early 2007.