The overall ratings of three biotechnology stocks are down on Portfolio Grader this week. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Trius Therapeutics, Inc.’s (TSRX) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Trius Therapeutics is a biopharmaceutical company. In Portfolio Grader’s specific subcategories of Earnings Growth, Earnings Momentum, Equity, Cash Flow and Sales Growth, TSRX also gets F’s. To get an in-depth look at TSRX, get Portfolio Grader’s complete analysis of TSRX stock.

Onconova Therapeutics Inc. (ONTX) ratings are on the decline this week as the company earns an F (“strong sell”). Last week, it received a D (“sell”). The stock gets F’s in Equity, Cash Flow and Sales Growth. For more information, get Portfolio Grader’s complete analysis of ONTX stock.

The rating of Fibrocell Science, Inc. (FCSC) slips from a C to a D. The stock gets F’s in Equity, Cash Flow and Sales Growth. To get an in-depth look at FCSC, get Portfolio Grader’s complete analysis of FCSC 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.