The grades of three Biotechnology stocks are better this week, according to the Portfolio Grader database. Every one of these stocks has an “A” (“strong buy”) or “B” overall (“buy”) rating.

QLT Inc. (NASDAQ:QLTI) is boosting its rating from a C (“hold”) to a B (“buy”) this week. QLT develops and commercializes pharmaceutical products for use in photodynamic therapy, the use of light activated drugs to treat disease. In Portfolio Grader’s specific subcategory of Earnings Momentum, QLTI also gets an A. Shares of the stock have been trading at an exceptionally rapid pace, up fourfold from the week prior. For more information, get Portfolio Grader’s complete analysis of QLTI stock.

Tranzyme (NASDAQ:TZYM) improves its rating from a C to a B this week. Tranzyme is a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing novel, first-in-class small molecule therapeutics. The stock price has risen 48.8% over the past month, better than the 1.2% increase the Nasdaq has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of TZYM stock.

Dyax (NASDAQ:DYAX) jumps from a C to a B rating this week. Dyax is engaged in the discovery, development and commercialization of novel biotherapeutics for unmet medical needs, with an emphasis on inflammatory and oncology indications. Wall Street seems to agree with the upgrade and has propelled the stock up 36.1% over the past month. For more information, get Portfolio Grader’s complete analysis of DYAX stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.