mitumomab mitumomab mitumomab (bec-2) is a mouse anti-bec-2 monoclonal antibody investigated for the treatment of small cell lung carcinoma in combination with bcg vaccination. mitumomab attacks tumour cells, while the vaccine is thought to activate the immune system. it was developed by imclone and merck. mitumomabmonoclonal antibodytypewhole antibodysourcemousetargetgd3 gangliosideclinical dataatc codenoneidentifierscas number216503-58-1 yiuphar/bps7981chemspidernoneuniikz9wfq2nxfkeggd05061 y ny (what is this?) (verify) the first phase iii clinical trial began in 1998. in 2005 and again in 2008, results were published showing no benefit to patients receiving mitumomab and bcg.