Expression of CD66a in multiple myeloma

Radioimmunotherapy in Combination with Reduced-Intensity Conditioning for Allogeneic Hematopoietic Cell Transplantation in Patients with Advanced Multiple Myeloma

Radioimmunotherapy (RIT) has the potential to reduce the incidence of relapse after allogeneic hematopoietic cell transplantation (allo-HCT) in patients with advanced-stage multiple myeloma (MM). In this study, we evaluated the efficacy of RIT in combination with chemotherapy-based reduced-intensity conditioning (RIC). RIT was based on the coupling of an anti-CD66 antibody to the beta emitter 188-rhenium (188-re) for targeted bone marrow irradiation. Between 2012 and 2018, 30 patients with MM, most of them heavily pretreated with various therapies including proteasome inhibitors, immunomodulatory drugs, anti-CD38 antibodies, and autologous hematopoietic cell transplantation (auto-HCT), were treated with a RIT-RIC combination before allo-HCT. In addition to a fludarabine plus melphalan- or treosulfan-based RIC, a median dose of 18.1 Gy (interquartile range [IQR], 14.6 to 24.1 Gy) was applied to the bone marrow. After a median duration of follow-up for surviving patients of 2.1 years (IQR, 1.3 to 3.0 years), the 2-year progression-free survival and overall survival rates were 43% (95% confidence interval [CI], 26% to 73%) and 55% (95% CI, 38% to 79%), respectively. The 2-year nonrelapse mortality and cumulative incidence of progression were 17% (95% CI, 3% to 30%) and 46% (95% CI, 25% to 67%), respectively. Renal toxicity and mucositis were the most frequent extramedullary side effects. In conclusion, the addition of RIT to RIC was safe and feasible and resulted in promising outcomes compared with those previously reported for RIC-based allo-HCT without the addition of RIT in patients with relapsed/refractory MM. Nevertheless, despite the addition of RIT, relapse after allo-HCT remained a major determinant of therapeutic failure. Therefore, the development of novel RIT strategies (eg, dual targeting strategies or combinations with adapter chimeric antigen receptor T cell-based therapies) is needed.

CEA-Related CAMs

The carcinoembryonic antigen (CEA) family comprises a large number of cellular surface molecules, the CEA-related cell adhesion molecules (CEACAMs), which belong to the Ig superfamily. CEACAMs exhibit a complex expression pattern in normal and malignant tissues. The majority of the CEACAMs are cellular adhesion molecules that are involved in a great variety of distinct cellular processes, for example in the integration of cellular responses through homo- and heterophilic adhesion and interaction with a broad selection of signal regulatory proteins, i.e., integrins or cytoskeletal components and tyrosine kinases. Moreover, expression of CEACAMs affects tumor growth, angiogenesis, cellular differentiation, immune responses, and they serve as receptors for commensal and pathogenic microbes. Recently, new insights into CEACAM structure and function became available, providing further elucidation of their kaleidoscopic functions.

Expression of CD66 in non-Hodgkin lymphomas and multiple myeloma

OBJECTIVES

⁹⁰Y-labeled anti-CD66b monoclonal antibody clone BW 250/183 was developed for treatment of tumors. The aim of the study was the analysis of CD66 expression in lymphoproliferative malignancies to expand the potential of anti-CD66-based therapy.

PATIENTS AND METHODS

Bone marrow samples from 260 patients were examined for the expression of CD66 on tumor cells in 104 B-chronic lymphocytic leukemias (B-CLL), 28 mantle cell lymphomas (MCL), 22 follicular lymphomas (FCL), 15 marginal zone lymphomas (MZL), 12 lymphoplasmacytic lymphomas (LPL), 13 diffuse large B cell lymphomas (DLBCL), 4 T-non-Hodgkin lymphomas (T-NHL), 3 B-NHL not otherwise specified (B-NHL NOS), 3 B acute lymphoblastic leukemias (B-ALL), and in 56 multiple myelomas (MM) by flow cytometry.

RESULTS

Positive (≥ 20%) expression of CD66abce clone Kat4c was detected in 76% of B-CLL and 76.8% of MM. The highest number of CD66abce-positive samples was in MCL and LPL (96.4% of 28 and 91.7% of 12 patients, respectively). Expression of CD66b clone BW 250/183 was examined in 114 of 260 samples. Positive expression was detected in 23.3% of B-CLL (6/35), 17.1% of MM (7/30), and 21.4% of MCL (3/14) samples.

CONCLUSION

The expression of CD66b compared to CD66abce was lower in all measured samples. Use of radiolabeled anti-CD66b antibody for the treatment of lymphoproliferative diseases appears to have limited preclinical substantiation.

Multiple myeloma presenting as CEA-producing rectal cancer

We report the case of a 57-year-old patient with multiple myeloma, characterized by extramedullary involvement of the rectum at presentation. Malignant plasma cells were found to produce carcinoembryonic antigen (CEA), a tumor antigen more commonly associated with rectal adenocarcinomas.