This week, 16 biotechnology stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

NPS Pharmaceuticals, Inc.’s (NPSP) grade is moving up to a B (“buy”) this week from last week’s C (“hold”). NPS Pharmaceuticals is a biopharmaceutical company focused on the development of treatment options for patients with rare gastrointestinal and endocrine disorders and serious unmet medical needs. In Portfolio Grader’s specific subcategory of Sales Growth, NPSP also gets an A. For more information, get Portfolio Grader’s complete analysis of NPSP stock.

The rating of Chemocentryx, Inc. (CCXI) moves up this week, rising from a C to a B. ChemoCentryx, a biopharmaceutical company, focuses on the discovery, development, and commercialization of orally-administered therapeutics to treat autoimmune diseases, inflammatory disorders, and cancer in the United States. For more information, get Portfolio Grader’s complete analysis of CCXI stock.

Sorrento Therapeutics, Inc. (SRNE) earns a B this week, jumping up from last week’s grade of C. For more information, get Portfolio Grader’s complete analysis of SRNE stock.

This week, TESARO, Inc. (TSRO) pushes up from a C to a B rating. Tesaro develops and commercializes cancer therapeutics and supportive care products. Shares of the stock have been changing hands at an unusually rapid pace, twice the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of TSRO stock.

This week, MediciNova, Inc. (MNOV) is making solid headway. The company’s rating improves to an A (“strong buy”) from last week’s B (“buy”) rating. Medicinova acquires, develops, and commercializes small molecule therapeutics. For more information, get Portfolio Grader’s complete analysis of MNOV stock.

Array BioPharma (ARRY) improves from a C to a B rating this week. 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. For more information, get Portfolio Grader’s complete analysis of ARRY stock.

BioTime, Inc. (BTX) shows solid improvement this week. The company’s rating rises from a C to a B. BioTime is a biotechnology company that focuses on regenerative medicine and blood plasma volume expanders. For more information, get Portfolio Grader’s complete analysis of BTX stock.

Cytokinetics, Incorporated (CYTK) is seeing ratings go up from a C last week to a B this week. Cytokinetics is a clinical-stage biopharmaceutical company focused on the discovery and development of novel small molecule therapeutics that modulate muscle function for the potential treatment of serious diseases and medical conditions. For more information, get Portfolio Grader’s complete analysis of CYTK stock.

Novavax, Inc.’s (NVAX) ratings are looking better this week, moving up to a B from last week’s C. Novavax creates novel vaccines to address a broad range of infectious diseases worldwide using proprietary virus-like particle technology. For more information, get Portfolio Grader’s complete analysis of NVAX stock.

Immunomedics, Inc. (IMMU) gets a higher grade this week, advancing from a C last week to a B. Immunomedics develops, manufactures, and sells diagnostic imaging and therapeutic products. For more information, get Portfolio Grader’s complete analysis of IMMU stock.

La Jolla Pharmaceutical Company (LJPC) boosts its rating from a B to an A this week. For more information, get Portfolio Grader’s complete analysis of LJPC stock.

This is a strong week for MannKind Corporation (MNKD). The company’s rating climbs to B from the previous week’s C. MannKind is a biopharmaceutical company focused on the development and commercialization of therapeutic products for diseases such as diabetes, cancer, inflammatory and autoimmune diseases. For more information, get Portfolio Grader’s complete analysis of MNKD stock.

Anacor Pharmaceuticals, Inc. (ANAC) shows solid improvement this week. The company’s rating rises from a B to an A. Anacor Pharmaceuticals focuses on discovering, developing, and commercializing small-molecule therapeutics derived from boron chemistry platform. Shares of the stock have been trading at an exceptionally rapid pace, up twofold from the week prior. For more information, get Portfolio Grader’s complete analysis of ANAC stock.

This week, Receptos, Inc. (RCPT) pushes up from a B to an A rating. Shares of the stock have been trading at an exceptionally rapid pace, up threefold from the week prior. For more information, get Portfolio Grader’s complete analysis of RCPT stock.

Ambit Biosciences Corp. (AMBI) earns a B this week, jumping up from last week’s grade of C. For more information, get Portfolio Grader’s complete analysis of AMBI stock.

Progenics Pharmaceuticals, Inc. (PGNX) is seeing ratings go up from a C last week to a B this week. Progenics Pharmaceuticals develops and distributes therapeutic products to treat the unmet medical needs of patients with debilitating conditions and life-threatening diseases. For more information, get Portfolio Grader’s complete analysis of PGNX 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.