Clinical parameters related to optimal tumor localization of indium-111-labeled mouse antimelanoma monoclonal antibody ZME-018.

Radioimmunolocalization of an 111In-labeled mouse antimelanoma monoclonal antibody (MoAb), ZME-018, was examined in 21 patients with metastatic malignant melanoma. Each patient received a single. i.v. infusion of MoAb at concentrations ranging from 1 mg to 20 mg, coupled to 5 mCi 111In by the chelating agent DPTA. No toxicity was observed in any patient. Total-body and regions of interest scans performed at 4, 24, and 72 hr following MoAb administration revealed uptake in 63 out of 105 previously diagnosed metastases for an overall sensitivity of 60%. Uptake was consistently observed in liver/spleen, and less frequently in bowel, testes, axillae and bone. Sensitivity of detection increased significantly at doses of MoAb above 2.5 mg, with 74% of lesions imaging at 20 mg/5 mCi compared with 29% at 2.5 mg/5 mCi (p less than 0.005). A significant correlation was observed between tumor uptake of 111In-MoAb conjugate and increasing tumor size. Soft-tissue lesions such as skin and lymph node metastases were imaged to a greater extent (76%) than visceral metastases (19%). In five of six patients, biopsies obtained from 3 days to 14 days after MoAb administration showed antibody present on tumor cells as demonstrated by flow cytometry and/or radioimmunoassay. Human anti-murine immunoglobulin responses were observed in seven of 17 patients studied. Mean plasma clearance of ZME-018 was prolonged with a T1/2 of 24.7 hr and increased slightly with increasing MoAb dose. Urinary excretion of 111In averaged 12.4% of the injected dose over 48 hours. Radioimmunolocalization of melanoma with 111In-labeled ZME-018 appears feasible. The sensitivity of the technique was related to dose, tumor size, and disease site.

Increased labeling of human melanoma cells in vitro using combinations of monoclonal antibodies recognizing separate cell surface antigenic determinants.

A panel of mouse anti-melanoma monoclonal antibodies (MoAb) were analyzed for reactivity with human melanoma cells singly and in combination. Five MoAb, ZME-018, 96.5, P94, 4.2, and 5.1, reactive with individual cell surface melanoma-associated antigens were tested with seven melanoma cell lines and seven fresh tumor biopsies. Cells were incubated with the MoAb, indirectly stained with fluorescein-conjugated goat anti-mouse immunoglobulin, and analyzed by flow cytometry. Percentage of labeled cells and relative fluorescence intensity (FI) with individual MoAb varied with different cell lines and biopsy samples. The most reactive MoAb, ZME-018, 96.5, and P94, labeled 29-93% of the cells from cell lines with relative FI of 2-59 units, thereby demonstrating phenotypic diversity of these cells. Similar results were obtained with cells derived from tumor biopsies, where 1-73% of cells were labeled and relative FI ranged from 0-27. These variations were reduced by using a "cocktail" of MoAb which recognized different melanoma-associated antigens. In cell lines both the percentage of labeled cells (range, 82-95%) and relative FI (range, 36-115) increased substantially (P less than 0.025 and P less than 0.005, respectively) when a "cocktail" prepared from all five MoAb rather than individual MoAb was used. A cocktail of MoAb increased the percentage of labeled tumor biopsy cells (range, 53-78; P less than 0.01) and relative FI (range, 11-69; P less than 0.025). The mean FI obtained by incubating cells with a cocktail of suboptimal concentrations of three MoAb (ZME-018, 96.5, P94) was 48 +/- 12 (SD), which was significantly increased compared to the mean FI seen with suboptimal concentrations of MoAb alone (ZME-018, 7 +/- 10; 96.5, 8 +/- 7; P94, 2 +/- 2; P less than 0.005). These findings were confirmed by radioimmunoassay using a combination of two MoAb, ZME-018 and 96.5. The data suggest that cocktails of MoAb were more effective than single MoAb alone for melanoma tumor cell labeling in vitro and might be more effective for tumor imaging and therapy.

The response rate at chemotherapy in advanced Hodgkin's disease reflected by peripheral lymphocyte count.

Forty patients with advanced Hodgkin's disease stage III and IV were treated with combination chemotherapy. Absolute lymphocyte count in the peripheral blood was determined before start to chemotherapy. Higher levels of lymphocytes in the peripheral blood were associated with higher chemotherapy response rates. This difference was statistically significant (P less than 0.05).