Plexxikon Inc., of Berkeley, Calif., treated the first patient in a Phase II study of PLX3397, a selective inhibitor designed to down-modulate macrophages and mast cells, in Hodgkin lymphoma. About 30 patients with relapsed or refractory disease are expected to be enrolled. Objectives of the study include assessing the efficacy of oral PLX3397 as measured by overall response rate, as well as the duration of response, the disease control rate, progression-free survival, response biomarkers and overall safety.