At least 13 biotechs gained or lost 10% or more on the week after presenting at the American Society of Clinical Oncology meeting in Chicago. At least eight companies gained more than 10%, led by a 30% move by Pharmacyclics Inc. (NASDAQ:PCYC). The company presented positive ORR data from three Phase Ib/II trials of ibrutinib, a Bruton's tyrosine kinase (Btk) inhibitor, in chronic lymphocytic leukemia (CLL), small cell lymphocytic lymphoma (SLL), and prolymphocytic leukemia (PLL) (see B29).

At least five biotechs lost 10% or more, with Cyclacel Pharmaceuticals Inc. (NASDAQ:CYCC) down 17%. However, the stock had gained 23% from May 16, when ASCO abstracts were released, to June 1, the start of the conference. Shares of Dendreon Corp. (NASDAQ:DNDN) fell 13% on Monday after multiple ASCO presentations featuring prostate cancer data from other companies. Zytiga abiraterone from Johnson & Johnson (NYSE:JNJ) met the