NEW YORK (TheStreet) -- XenoPort (XNPT)  shares are soaring 56.59% to $6.89 Monday on heavy trading volume, following the announcement that Arbor Pharmaceuticals will buy the biopharmaceutical company in a deal valued at around $467 million. 

"We evaluated many potential options to maximize the value for stockholders and believe this transaction represents a great outcome for XenoPort stockholders," XenoPort CEO Vincent J. Angotti stated.

Under the terms of the deal, Arbor will buy all of XenoPort's outstanding shares for $7.03 a share.

During the acquisition announcement, Arbor CEO Ed Schutter also added that the company is pleased to be adding Horizant, XenoPort's relentless legs syndrome treatment to its growing portfolio. 

Based in Santa Clara, CA, XenoPort focuses on developing and commercializing a portfolio of product candidates for the treatment of neurological and other disorders in the U.S.

Separately, TheStreet Ratings currently has a "Sell" rating on the stock with a letter grade of D-.

This is driven by multiple weaknesses, which we believe should have a greater impact than any strengths, and could make it more difficult for investors to achieve positive results compared to most of the stocks we cover. The company's weaknesses can be seen in multiple areas, such as its disappointing return on equity, generally disappointing historical performance in the stock itself and generally high debt management risk.

Recently, TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this article's author.

You can view the full analysis from the report here: XNPT