BETHESDA, Md--The Oncologic Drugs Advisory Committee (ODAC), in a vote of 9 to 4, recommended that Verluma imaging be approved for the initial staging of patients with biopsy-confirmed small-cell lung cancer (SCLC). Verluma is a murine monoclonal antibody (MoAb) Fab fragment, targeted to the NR-LU-10 antigen and linked to technetium-99m.
Dr. Darrell Salk, of the University of Washington, Seattle, presented information on Verluma on behalf of the sponsoring company, NeoRx Corporation (Seattle). Dr. Salk emphasized that Verluma is intended only for cancer staging and should not be used for the differential diagnosis of suspected lung tumors or metastatic disease.
Verluma whole body gamma camera imaging (see figure at right) is performed on an outpatient basis and has an outstanding history of safety in studies of more than 500 patients, Dr. Salk said. It results in only a 6% rate of low-level HAMA (human antimouse antibody) responses, with no associated toxicity.
Most of the radioactive antibody from the test goes to the kidneys, where it is excreted. The rest goes to the tumor and remains concentrated there. The radioactive antibody will also show up in the bone marrow if cancer cells have traveled into the blood, he said
When Verluma imaging shows extensive cancer, no further testing is needed prior to the initiation of palliative treatment. When limited disease is revealed, then additional diagnostic tests should be performed.
In the pivotal phase III study conducted from July 1988 to July 1989 at 24 US sites, a single dose was used, and imaging took place 14 to 17 hours after injection, Dr. Salk said.
The Verluma imaging process correctly staged 73 of 89 newly diagnosed SCLCs (82% accuracy), compared with 71% accuracy for CT of the abdomen, 63% for bone scan, 54% for bone marrow aspiration, 49% for CT of the head, and 44% for physical examination.