This week, the ratings of 10 biotechnology stocks on Portfolio Grader are down. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Ocata Therapeutics, Inc.’s (OCAT) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. In Portfolio Grader’s specific subcategories of Earnings Momentum, Equity and Cash Flow, OCAT also gets an F. For more information, get Portfolio Grader’s complete analysis of OCAT stock.

EPIRUS Biopharmaceuticals, Inc.’s (EPRS) rating weakens this week, dropping to a D versus last week’s C. The stock also gets an F in Earnings Revisions. To get an in-depth look at EPRS, get Portfolio Grader’s complete analysis of EPRS stock.

Ohr Pharmaceutical Inc (OHRP) is having a tough week. The company’s rating falls from a C to a D. Ohr Pharmaceutical develops pharmaceuticals for wound care and to treat cachexia. The stock gets F’s in Earnings Revisions and Equity. For more information, get Portfolio Grader’s complete analysis of OHRP stock.

This is a rough week for Trius Therapeutics, Inc. (TSRX). The company’s rating falls to D from the previous week’s C. Trius Therapeutics is a biopharmaceutical company. The stock gets F’s in Earnings Growth, Earnings Momentum and Equity. Cash Flow and Sales Growth also get F’s. To get an in-depth look at TSRX, get Portfolio Grader’s complete analysis of TSRX stock.

The rating of Vical Incorporated (VICL) declines this week from a C to a D. Vical researches and develops biopharmaceutical products based on its patented DNA delivery technologies for the prevention and treatment of serious or life-threatening diseases. The stock gets F’s in Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of VICL stock.

Tenax Therapeutics, Inc. (TENX) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). The stock receives F’s in Earnings Momentum, Earnings Revisions and Equity. Cash Flow and Sales Growth also get F’s. The stock has a trailing PE Ratio of 98.00. To get an in-depth look at TENX, get Portfolio Grader’s complete analysis of TENX stock.

This week, Synergy Pharmaceuticals, Inc. (SGYP) drops from a D to an F rating. Synergy Pharmaceuticals is a biopharmaceutical company focused on the development of drugs to treat gastrointestinal disorders and diseases. The stock gets F’s in Equity and Cash Flow. As of March 18, 2015, 14.7% of outstanding Synergy Pharmaceuticals, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of SGYP stock.

Verastem, Inc. (VSTM) earns an F this week, moving down from last week’s grade of D. Verastem is a biopharmaceutical company which is focused on discovering and developing novel drugs that selectively target cancer stem cells in breast and other cancers along with proprietary companion diagnostics. The stock gets F’s in Equity and Cash Flow. To get an in-depth look at VSTM, get Portfolio Grader’s complete analysis of VSTM stock.

Celldex Therapeutics, Inc. (CLDX) gets weaker ratings this week as last week’s C drops to a D. Celldex Therapeutics is engaged in the discovery, development and commercialization of products that harness the human immune system to prevent and treat disease. The stock also rates an F in Equity. As of March 18, 2015, 24% of outstanding Celldex Therapeutics, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of CLDX stock.

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