This week, the ratings of 13 biotechnology stocks on Portfolio Grader are down. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

CEL-SCI Corporation (CVM) is on the decline this week, earning a D (“sell”) after receiving a C (“hold”) last week. 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. For more information, get Portfolio Grader’s complete analysis of CVM stock.

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

This week, Ohr Pharmaceutical Inc’s (OHRP) rating worsens to a D from the company’s C rating a week ago. 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.

Slipping from a C to a D rating, Trius Therapeutics, Inc. (TSRX) takes a hit this week. Trius Therapeutics is a biopharmaceutical company. The stock receives 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) 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. For more information, get Portfolio Grader’s complete analysis of VICL stock.

Tenax Therapeutics, Inc. (TENX) 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 Earnings Momentum, Earnings Revisions and Equity. Cash Flow and Sales Growth also get F’s. To get an in-depth look at TENX, get Portfolio Grader’s complete analysis of TENX stock.

Synergy Pharmaceuticals, Inc. (SGYP) earns an F this week, moving down 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 June 17, 2015, 19.9% of outstanding Synergy Pharmaceuticals, Inc. shares were held short. Shares of the stock have been exchanging at an usually rapid pace, twice the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of SGYP stock.

The rating of Lexicon Pharmaceuticals, Inc. (LXRX) declines this week from a C to a D. Lexicon Pharmaceuticals researches treatments for diabetes and obesity, cardiovascular disease, psychiatric and neurological disorders, cancer, immune system disorders, and ophthalmic disease. The stock gets F’s in Equity and Cash Flow. Shares of the stock are changing hands at twice the rate they were a week ago. To get an in-depth look at LXRX, get Portfolio Grader’s complete analysis of LXRX stock.

Verastem, Inc. (VSTM) earns an F this week, falling 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. As of June 17, 2015, 10.9% of outstanding Verastem, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of VSTM stock.

This week, Celldex Therapeutics, Inc.’s (CLDX) rating worsens to a D from the company’s C rating a week ago. 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 gets an F in Equity. As of June 17, 2015, 16.7% of outstanding Celldex Therapeutics, Inc. shares were held short. To get an in-depth look at CLDX, get Portfolio Grader’s complete analysis of CLDX stock.

Trevena, Inc. (TRVN) gets weaker ratings this week as last week’s C drops to a D. The stock gets F’s in Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of TRVN stock.

This is a rough week for Applied Genetic Technologies Corp. (AGTC). The company’s rating falls to D from the previous week’s C. The stock also gets an F in Equity. Shares of the stock have been changing hands at an unusually rapid pace, four times the rate of the week prior. To get an in-depth look at AGTC, get Portfolio Grader’s complete analysis of AGTC stock.

Vital Therapies, Inc.’s (VTL) rating weakens this week, dropping to a D versus last week’s C. The stock gets F’s in Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of VTL 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.