MEI Pharma has acquired exclusive worldwide rights to the investigational drug candidate PWT143 from Pathway Therapeutics, for an undisclosed upfront payment with no future milestone or royalty obligations.   In preclinical studies, PWT143 has been found to be a potent and highly selective oral inhibitor of phosphatidylinositide 3-kinase (PI3K) delta, a molecular target that has been shown to play a critical role in the proliferation and survival of hematologic cancer cells. MEI Pharma anticipat...