Late Monday, Pfizer Inc. disclosed its decision to halt a Phase III trial (B1931008) of inotuzumab ozogamicin, an investigational antibody-drug conjugate (ADC) composed of a monoclonal antibody targeting CD22, administered in combination with Rituxan (rituximab, Roche AG and Biogen Idec Inc.), in relapsed or refractory CD22-positive aggressive non-Hodgkin's lymphoma (NHL).