Six Biotechnology stocks are moving up in their overall rating this week, according to the Portfolio Grader database. Every one of these is graded an “A” (“strong buy”) or “B” overall (“buy”).

Athersys (NASDAQ:ATHX) ups its rating to a B (“buy”) this week after earning a C (“hold”) in the week before. Athersys is a biopharmaceutical company that engages in the discovery and development of therapeutic products in various disease areas in the United States. The stock price has risen 42.3% over the past month, better than the 1.1% increase the Nasdaq has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of ATHX stock.

This week, Ariad Pharmaceuticals’ (NASDAQ:ARIA) ratings are up from a C last week to a B. ARIAD Pharmaceuticals is an oncology company that focuses on the discovery, development, and commercialization of medicines for cancer patients. For more information, get Portfolio Grader’s complete analysis of ARIA stock.

This week, Neurocrine Biosciences (NASDAQ:NBIX) pushes up from a C to a B rating. Neurocrine Biosciences is focused on the discovery and development of therapeutics for neuropsychiatric, neuroinflammatory, and neurodegenerative diseases and disorders. Wall Street seems to agree with the upgrade and has propelled the stock up 6% over the past month. For more information, get Portfolio Grader’s complete analysis of NBIX stock.

Array BioPharma’s (NASDAQ:ARRY) ratings are looking better this week, moving up to a B from last week’s C. Array BioPharma is a biopharmaceutical company focused on the discovery, development and commercialization of targeted small molecule drugs to treat patients afflicted with cancer, inflammatory and metabolic diseases. Investors seem to agree with the upgraded status of the stock, and have pushed the stock up 20.9% over the past month. For more information, get Portfolio Grader’s complete analysis of ARRY stock.

This week, Celldex Therapeutics (NASDAQ:CLDX) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). Celldex Therapeutics is engaged in the discovery, development and commercialization of products that harness the human immune system to prevent and treat disease. Wall Street has pushed the stock higher by 16.7% over the past month. For more information, get Portfolio Grader’s complete analysis of CLDX stock.

Insmed Inc. (NASDAQ:INSM) shows solid improvement this week. The company’s rating rises from a C to a B. Insmed develops and commercializes drugs that treat metabolic diseases, endocrine disorders and oncology. For more information, get Portfolio Grader’s complete analysis of INSM 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.