CHICAGO -(Dow Jones)- Two small midstage studies of an experimental therapy being developed by Avant Immunotherapeutics Inc. (AVAN) and Pfizer Inc. (PFE) showed positive results in an aggressive form of brain cancer. The results come less than two months after Pfizer cut a deal to buy the exclusive worldwide license to CDX-110 by paying $40 million and investing $10 million in Avant, as well as promising to pay $390 million in potential milestone payments and double-digit royalties.