The overall ratings of 10 Biotechnology stocks are down on Portfolio Grader this week. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This is a rough week for Infinity Pharmaceuticals, Inc. (INFI). The company’s rating falls to F from the previous week’s D. Infinity Pharmaceuticals, Inc. researches and develops cancer drugs. The company also gets F’s in sales growth, earnings momentum, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of INFI stock.

Stellar Biotechnologies, Inc. (SBOT) earns a D this week, moving down from last week’s grade of C. The company also gets F’s in return on equity. For more information, get Portfolio Grader’s complete analysis of SBOT stock.

Slipping from a C to a D rating, Raptor Pharmaceutical Corp. (RPTP) takes a hit this week. Raptor Pharmaceutical Corp. researches existing drugs to improve them through specialized drug targeting methods and formulation changes. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of RPTP stock.

Cerulean Pharma, Inc. (CERU) is having a tough week. The company’s rating falls from a C to a D. The company also gets F’s in sales growth, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of CERU stock.

Orexigen Therapeutics, Inc. (OREX) declines this week from a C to a D. Orexigen Therapeutics, Inc. is focused on the development and commercialization of pharmaceutical products for the treatment of the central nervous system disorders with an initial focus on obesity. The company also gets F’s in return on equity. For more information, get Portfolio Grader’s complete analysis of OREX stock.

MannKind Corporation (MNKD) gets weaker ratings this week as last week’s D drops to a F. MannKind Corporation is a biopharmaceutical company focused on the development and commercialization of therapeutic products for diseases such as diabetes, cancer, inflammatory and autoimmune diseases. The company also gets F’s in earnings surprise and free cash flow. For more information, get Portfolio Grader’s complete analysis of MNKD stock.

This week, Corbus Pharmaceuticals Holdings Inc’s (CRBP) rating worsens to a D from the company’s C rating a week ago. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of CRBP stock.

Rosetta Genomics Ltd (ROSG) experiences a ratings drop this week, going from last week’s C to a D. Rosetta Genomics Ltd is a biomedical company that discovers and develops diagnostic and therapeutic products based on a recently discovered group of genes known as microRNAs. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of ROSG stock.

This week, CTI BioPharma Corp. (CTIC) drops from a D to a F rating. CTI BioPharma Corp. develops, acquires, and sells new treatments for cancer. The company also gets F’s in sales growth, earnings growth, earnings revisions, earnings surprise, and free cash flow. For more information, get Portfolio Grader’s complete analysis of CTIC stock.

Immune Pharmaceuticals, Inc. (IMNP) slips from a D to a F this week. The company also gets F’s in earnings surprise, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of IMNP 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.