Pharmacyclics' PCI-32765: Lymphocyte Counts Rise, Then Response Rates Do.

SAN DIEGO u Pharmacyclics Inc. grabbed the spotlight on Friday with a $150 million up-front deal that could reach a total of $975 million with Janssen Biotech Inc. for Phase II hematologic cancer drug PCI-32765. At the 53rd Annual American Society of Hematology meeting, hematologists and investors got to see some of what all the fuss is about. (See BioWorld Today, Dec. 12, 2011.)

The company presented an update from its Phase Ib/II trial testing PCI-32765 in relapsed or refractory chronic lymphocytic leukemia (CLL). Response rates to the drug continue to rise, with the partial response rate now at 70 percent. Interim data presented at last year's ASH meeting showed a partial response rate of 25 percent, while by this year's ASCO meeting, that rate had risen to 48 percent.

An unusual feature of the drug is that at the start of treatment, PCI-32765 actually causes lymphocyte counts to rise u not exactly the hoped-for response to a leukemia drug.

The …