Through his career he was noted for development of targeted cancer treatment capabilities. Specifically, he led the development of the breast cancer treatment Herceptin. The treatment is based on a monoclonal antibody that targets the HER2 protein, which is impacted in aggressive breast cancers. He led the early-stage clinical trial of the drug and led to findings that this targeted treatment along with chemotherapy could extend the lives of patients with HER2 positive breast cancers. He was involved in the clinical development of targeted drugs for cancer including cetuximab, pertuzumab, trastuzumab and lapatinib.[9][10] His research focus extended to the study of drug resistance in some cancers. He also studied drugs that could target tumors stemming from the PI3K mutation.