This week, the overall grades of 16 Biotechnology stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This week, Avalanche Biotechnologies Inc (AAVL) drops from a D to a F rating. The company also gets F’s in earnings revisions, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of AAVL stock.

This week, Chimerix, Inc.’s (CMRX) 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 CMRX stock.

Regulus Therapeutics Inc. (RGLS) earns a D this week, moving down from last week’s grade of C. Regulus Therapeutics Inc. focuses on the discovery and development of drugs that target microRNAs to treat various diseases in the United States. 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 RGLS stock.

Slipping from a C to a D rating, Zafgen, Inc. (ZFGN) takes a hit this week. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of ZFGN stock.

Progenics Pharmaceuticals, Inc.’s (PGNX) rating weakens this week, dropping to a D versus last week’s C. Progenics Pharmaceuticals, Inc. develops and distributes therapeutic products to treat the unmet medical needs of patients with debilitating conditions and life-threatening diseases. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings momentum, and return on equity. For more information, get Portfolio Grader’s complete analysis of PGNX stock.

ARCA biopharma, Inc. (ABIO) slips from a C to a D this week. ARCA biopharma, Inc. is a biopharmaceutical company whose main focus is developing genetically-targeted therapies for heart failure and other cardiovascular diseases. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of ABIO stock.

Bio Blast Pharma Ltd. (ORPN) gets weaker ratings this week as last week’s C drops to a D. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of ORPN stock.

This is a rough week for Kindred Biosciences, Inc. (KIN). The company’s rating falls to F from the previous week’s D. 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 KIN stock.

Northwest Biotherapeutics, Inc. (NWBO) is having a tough week. The company’s rating falls from a C to a D. Northwest Biotherapeutics, Inc. engages in discovering, developing, and commercializing immunotherapy products to treat cancers in the United States. The company also gets F’s in sales growth and free cash flow. For more information, get Portfolio Grader’s complete analysis of NWBO stock.

Idera Pharmaceuticals, Inc. (IDRA) declines this week from a C to a D. Idera Pharmaceuticals, Inc. is engaged in the discovery and development of DNA- and RNA-based drug candidates targeted to Toll-Like Receptors (TLRs) to treat infectious diseases, autoimmune and inflammatory diseases, cancer, asthma and allergies, and for use as vaccine adjuvants. 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 IDRA stock.

Conatus Pharmaceuticals Inc. (CNAT) experiences a ratings drop this week, going from last week’s D to a F. 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 CNAT stock.

Brainstorm Cell Therapeutics Inc. (BCLI) declines this week from a C to a D. The company also gets F’s in earnings revisions, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of BCLI stock.

This week, Biota Pharmaceuticals, Inc. (BOTA) drops from a C to a D rating. Biota Pharmaceuticals, Inc. is an anti-infective drug development company with expertise in respiratory diseases, particularly influenza. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of BOTA stock.

MEI Pharma, Inc. (MEIP) is having a tough week. The company’s rating falls from a C to a D. MEI Pharma, Inc. is an oncology company focused on the clinical development of novel therapeutics targeting cancer metabolism. The company also gets F’s in return on equity and free cash flow. For more information, get Portfolio Grader’s complete analysis of MEIP stock.

This week, NephroGenex, Inc.’s (NRX) rating worsens to a F from the company’s D rating a week ago. 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 NRX stock.

This is a rough week for Navidea Biopharmaceuticals, Inc. (NAVB). The company’s rating falls to D from the previous week’s C. Navidea Biopharmaceuticals, Inc. is focused on the development and commercialization of precision radiopharmaceutical diagnostics for diseases such as cancer. The company also gets F’s in free cash flow. For more information, get Portfolio Grader’s complete analysis of NAVB 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.