This week, the overall grades of 23 Biotechnology stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

BioMarin Pharmaceutical Inc.’s (BMRN) rating weakens this week, dropping to a F versus last week’s D. BioMarin Pharmaceutical Inc. develops and commercializes innovative pharmaceuticals for serious diseases and medical conditions. The company also gets F’s in earnings revisions, earnings surprise, earnings momentum, and return on equity. For more information, get Portfolio Grader’s complete analysis of BMRN stock.

Gilead Sciences, Inc. (GILD) earns a F this week, moving down from last week’s grade of D. Gilead Sciences, Inc. is a research-based biopharmaceutical company that discovers, develops, and commercializes therapeutics to advance the care of patients suffering from life-threatening diseases. For more information, get Portfolio Grader’s complete analysis of GILD stock.

Emergent BioSolutions Inc. (EBS) declines this week from a C to a D. Emergent BioSolutions Inc. develops and produces immunobiotics, pharmaceutical products that assist the body’s immune system to prevent or treat disease. The company also gets F’s in earnings surprise and earnings momentum. For more information, get Portfolio Grader’s complete analysis of EBS stock.

This is a rough week for AMAG Pharmaceuticals, Inc. (AMAG). The company’s rating falls to F from the previous week’s D. AMAG Pharmaceuticals, Inc. utilizes its proprietary technology for the development and commercialization of a therapeutic iron compound to treat anemia and novel imaging agents to aid in the diagnosis of cancer and cardiovascular disease. The company also gets F’s in operating margin growth and earnings growth. For more information, get Portfolio Grader’s complete analysis of AMAG stock.

This week, Myriad Genetics, Inc. (MYGN) drops from a C to a D rating. Myriad Genetics, Inc. develops and markets molecular diagnostic products to provide physicians with information to help guide the care of their patients, to prevent disease, delay the onset of disease, or catch disease at an early stage. The company also gets F’s in earnings revisions. For more information, get Portfolio Grader’s complete analysis of MYGN stock.

FibroGen, Inc. (FGEN) 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, earnings revisions, and return on equity. For more information, get Portfolio Grader’s complete analysis of FGEN stock.

This week, Adamas Pharmaceuticals, Inc.’s (ADMS) rating worsens to a D from the company’s C rating a week ago. 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 ADMS stock.

Seres Therapeutics Inc (MCRB) gets weaker ratings this week as last week’s D drops 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 MCRB stock.

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

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

Novavax, Inc. (NVAX) experiences a ratings drop this week, going from last week’s D to a F. Novavax, Inc. creates novel vaccines to address a broad range of infectious diseases worldwide using proprietary virus-like particle technology. The company also gets F’s in sales growth, earnings revisions, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of NVAX stock.

Immune Design Corp. (IMDZ) gets weaker ratings this week as last week’s D drops to a F. 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 IMDZ stock.

ADMA Biologics, Inc.’s (ADMA) rating weakens this week, dropping to a D versus last week’s C. 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 ADMA stock.

This week, Spectrum Pharmaceuticals, Inc. (SPPI) drops from a C to a D rating. Spectrum Pharmaceuticals, Inc. is a biotechnology company with fully integrated commercial and drug development operations with a primary focus in oncology. The company also gets F’s in sales growth, earnings surprise, and return on equity. For more information, get Portfolio Grader’s complete analysis of SPPI stock.

Merrimack Pharmaceuticals, Inc. (MACK) earns a F this week, moving down from last week’s grade of D. Merrimack Pharmaceuticals, Inc. is focused on the discovery, development and commercialization of drugs for the treatment of immunological and autoimmune diseases with an initial focus on cancer. The company also gets F’s in earnings revisions and free cash flow. For more information, get Portfolio Grader’s complete analysis of MACK stock.

Sangamo BioSciences, Inc. (SGMO) is having a tough week. The company’s rating falls from a D to a F. Sangamo BioSciences, Inc. is engaged in the research, development and commercialization of novel transcription factors for gene regulation and gene modification. The company also gets F’s in sales growth, earnings revisions, earnings surprise, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of SGMO stock.

VistaGen Therapeutics, Inc. (VTGN) experiences a ratings drop this week, going from last week’s D to a F. The company also gets F’s in free cash flow. For more information, get Portfolio Grader’s complete analysis of VTGN stock.

PDL BioPharma, Inc. (PDLI) slips from a D to a F this week. PDL BioPharma, Inc. engages in intellectual property asset management and patent portfolio and related assets investment activities. The company also gets F’s in sales growth, earnings growth, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of PDLI stock.

This is a rough week for Tenax Therapeutics, Inc. (TENX). The company’s rating falls to F from the previous week’s D. The company also gets F’s in earnings revisions and return on equity. For more information, get Portfolio Grader’s complete analysis of TENX stock.

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

This week, OncoSec Medical Incorporated’s (ONCS) rating worsens to a F from the company’s D 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 ONCS stock.

Actinium Pharmaceuticals, Inc. (ATNM) declines this week from a C 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 ATNM stock.

ArQule, Inc. (ARQL) is having a tough week. The company’s rating falls from a C to a D. ArQule, Inc. is a biotechnology company that is engaged in the research and development of cancer therapeutics. 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 ARQL 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.