This week, the overall grades of 10 biotechnology stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This week, CEL-SCI Corporation (CVM) falls to a D (“sell”), worse than last week’s grade of C (“hold”). CEL-SCI is developing new immune system based treatments for cancer and infectious diseases. In Portfolio Grader’s specific subcategories of Equity and Cash Flow, CVM also gets F’s. To get an in-depth look at CVM, get Portfolio Grader’s complete analysis of CVM stock.

The rating of EPIRUS Biopharmaceuticals, Inc. (EPRS) declines this week from a C to a D. The stock also gets an F in Earnings Revisions. For more information, get Portfolio Grader’s complete analysis of EPRS stock.

Ohr Pharmaceutical Inc (OHRP) earns a D this week, moving down from last week’s grade of C. Ohr Pharmaceutical develops pharmaceuticals for wound care and to treat cachexia. The stock gets F’s in Earnings Revisions and Equity. To get an in-depth look at OHRP, get Portfolio Grader’s complete analysis of OHRP stock.

Trius Therapeutics, Inc.’s (TSRX) rating weakens this week, dropping to a D versus last 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. For more information, get Portfolio Grader’s complete analysis of TSRX stock.

The rating of Vical Incorporated (VICL) slips 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. To get an in-depth look at VICL, get Portfolio Grader’s complete analysis of VICL stock.

Tenax Therapeutics, Inc.’s (TENX) rating falls this week to an F (“strong sell”), down from last week’s D (“sell”). The stock receives F’s in Earnings Momentum, Earnings Revisions and Equity. Cash Flow and Sales Growth also get F’s. For more information, get Portfolio Grader’s complete analysis of TENX stock.

Synergy Pharmaceuticals, Inc. (SGYP) earns an F this week, falling from last week’s grade of D. 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 April 29, 2015, 18.6% of outstanding Synergy Pharmaceuticals, Inc. shares were held short. To get an in-depth look at SGYP, get Portfolio Grader’s complete analysis of SGYP stock.

Slipping from a D to an F rating, Verastem, Inc. (VSTM) takes a hit this week. 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. As of April 29, 2015, 10.1% of outstanding Verastem, Inc. shares were held short. For more information, 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 April 29, 2015, 16.2% of outstanding Celldex Therapeutics, Inc. shares were held short. Shares of the stock have been trading at an exceptionally rapid pace, up twofold from the week prior. To get an in-depth look at CLDX, get Portfolio Grader’s complete analysis of CLDX stock.

This is a rough week for Trevena, Inc. (TRVN). The company’s rating falls to D from the previous week’s C. The stock gets F’s in Equity and Cash Flow. For more information, 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.