Citations

Thalidomide, initially introduced as a sedative, was withdrawn from the market in the early 1960s after it was found to be a teratogen. However, it later found use as an investigational agent in the treatment of erythema nodosum leprosum, oral ulcers, graft versus host disease, and wasting associated with the human immunodeficiency syndrome. Its antiangiogenic properties were recognized in the early 1990s during a period where the importance of angiogenesis became increasingly apparent as a critical step in the in the proliferation and spread of malignant neoplasms. This led to the evaluation of thalidomide as an antiangiogenic agent in the treatment of several cancers. Thalidomide has already become part of standard therapy for the treatment of patients with relapsed and refractory multiple myeloma. It has also been found to have varying degree of benefit in various other malignancies. Although more clinical trials are needed, Kaposi's sarcoma and myelofibrosis represent other malignancies in which thalidomide has already demonstrated promising activity. The mechanism of action of thalidomide in cancer is still unclear, but do appear to be mediated by several other mechanisms in addition to its anti-angiogenic properties. This article reviews the current status of thalidomide for the treatment of non-plasma-cell malignancies.

AbstractWe compared the angiogenic potential of bone marrow plasma and the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors on plasma cells from patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and newly diagnosed multiple myeloma (NMM). Cytokine and cytokine-receptor expression was studied by bone marrow immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (RT-PCR) on sorted plasma cells, and quantitative Western blot analysis. Bone marrow angiogenic potential was studied using a human in vitro angiogenesis assay. The expression levels of VEGF, bFGF, and their receptors were similar among MGUS, SMM, and NMM. Sixty-one percent of NMM samples stimulated angiogenesis in the in vitro angiogenesis assay compared with SMM (0%) and MGUS (7%) (P < .001). Importantly, 63% of MGUS samples inhibited angiogenesis compared with SMM (43%) and NMM (4%) (P < .001). The inhibitory activity was heat stable, not overcome by the addition of VEGF, and corresponded to a molecular weight below 10 kd by size-exclusion chromatography. Our results suggest that increasing angiogenesis from MGUS to NMM is, at least in part, explained by increasing tumor burden rather than increased expression of VEGF/bFGF by individual plasma cells. The active inhibition of angiogenesis in MGUS is lost with progression, and the angiogenic switch from MGUS to NMM may involve a loss of inhibitory activity. (Blood. 2004; 104:1159-1165)

Abstract Multiple myeloma (MM) and primary systemic amyloidosis (AL) remain incurable disorders, and new treatments targeted to the malignant plasma cells are needed. Alemtuzumab is a humanized monoclonal antibody to CD52 and has activity in chronic lymphocytic leukemia. We examined the CD52 expression on CD45+ and CD45- plasma cell populations to evaluate the potential for using alemtuzumab for these disorders. Bone marrows from 61 patients (29 AL, 23 MM, and 9 MGUS [monoclonal gammopathies of undetermined significance]) were studied using 3-color (CD38/45/52) flow cytometry. Among those with MGUS, MM, and AL, 67%, 52%, and 35%, respectively, were positive for CD52 expression. The CD52 expression was predominantly confined to the clonal CD38+/CD45+ plasma cell fraction with median expression of 68%, 88%, and 82% in MGUS, MM, and AL, respectively, compared with 18%, 6%, and 9% among the CD45- plasma cell population. Clinical trials are warranted in these diseases to learn the therapeutic benefit of anti-CD52 immunotherapy.

Angiogenesis plays an important role in the biology of multiple myeloma (MM) and has prognostic importance in this disease. Solitary plasmacytoma is a localized plasma cell malignancy that progresses to MM in a significant number of patients. We examined if angiogenesis is increased in solitary plasmacytoma and if it can help identify patients likely to progress to myeloma. We studied angiogenesis in plasmacytoma biopsy samples and bone marrow biopsies from 25 patients. High-grade angiogenesis was present in 64% of plasmacytomas. In contrast, bone marrow angiogenesis was low in all patients. Patients with high-grade angiogenesis in the plasmacytoma sample were more likely to progress to myeloma and had a shorter progression-free survival compared with patients with low-grade angiogenesis (P = .02). Angiogenesis is increased in solitary plasmacytoma and is a significant predictor of progression to myeloma and provides further evidence of its importance in the pathogenesis of myeloma.