In this trial of the treatment of newly diagnosed multiple myeloma, we compared a protocol that entailed a hematopoietic stem-cell autograft followed by an allograft from an HLA-identical sibling with a protocol of tandem autografts. We enrolled 162 consecutive patients with newly diagnosed myeloma who were 65 years of age or younger and who had at least one sibling. All patients were initially treated with vincristine, doxorubicin, and dexamethasone, followed by melphalan and autologous stem-cell rescue. Patients with an HLA-identical sibling then received nonmyeloablative total-body irradiation and stem cells from the sibling. Patients without an HLA-identical sibling received two consecutive myeloablative doses of melphalan, each of which was followed by autologous stem-cell rescue. The primary end points were overall survival and event-free survival. After a median follow-up of 45 months (range, 21 to 90), the median overall survival and event-free survival were longer in the 80 patients with HLA-identical siblings than in the 82 patients without HLA-identical siblings (80 months vs. 54 months, P=0.01; and 35 months vs. 29 months, P=0.02, respectively). Among patients who completed their assigned treatment protocols, treatment-related mortality did not differ significantly between the double-autologous-transplant group (46 patients) and the autograft–allograft group (58 patients, P=0.09), but disease-related mortality was significantly higher in the double-autologous-transplant group (43% vs. 7%, P<0.001). The cumulative incidence rates of grades II, III, and IV graft-versus-host disease (GVHD) combined and of grade IV GVHD in the autograft–allograft group were 43% and 4%, respectively. Overall, 21 of 58 patients (36%) were in complete remission after a median follow-up of 38 months (range, 10 to 72) after allografting. Of the 46 patients who received two autografts, 25 (54%) died. Among patients with newly diagnosed myeloma, survival in recipients of a hematopoietic stem-cell autograft followed by a stem-cell allograft from an HLA-identical sibling is superior to that in recipients of tandem stem-cell autografts. (ClinicalTrials.gov number, NCT00415987.)

Indoleamine 2,3-dioxygenase (IDO) is a novel immunosuppressive agent expressed in some subsets of normal and neoplastic cells, including acute myeloid leukemia (AML) cells. Here, we show that IDO expression correlates with increased circulating CD4⁺CD25⁺FOXP3⁺ T cells in patients with AML at diagnosis. In vitro, IDO⁺ AML cells increase the number of CD4⁺ CD25⁺ T cells expressing surface CTLA-4 and FOXP3 mRNA, and this effect is completely abrogated by the IDO inhibitor, 1-methyl tryptophan (1-MT). Purified CD4⁺CD25⁺ T cells obtained from coculture with IDO⁺ AML cells act as T regulatory (T_reg) cells because they do not proliferate, do not produce interleukin (IL)–2, and inhibit naive T-cell proliferation. Coculture with IDO⁺AML cells results in the conversion of CD4⁺CD25⁻ into CD4⁺CD25⁺ T cells, which is completely abrogated by 1-MT. Moreover, in mice, intrasplenic injection of IDO⁺ leukemia/lymphoma A20 cells induces the expansion of bona fide T_reg cells by conversion of CD4⁺CD25⁻ T cells; this effect is counteracted by 1-MT treatment. These data indicate that AML cells induce T-cell tolerance by directly converting CD4⁺CD25⁻ T cells into CD4⁺CD25⁺ T_reg cells through an IDO-dependent mechanism.

It is unknown whether zoledronic acid (ZA) at clinically relevant doses is active against tumours not located in bone. Mice transgenic for the activated ErbB‐2 oncogene were treated with a cumulative number of doses equivalent to that recommended in human beings. A significant increase in tumour‐free and overall survival was observed in mice treated with ZA. At clinically compatible concentrations, ZA modulated the mevalonate pathway and affected protein prenylation in both tumour cells and macrophages. A marked reduction in the number of tumour‐associated macrophages was paralleled by a significant decrease in tumour vascularization. The local production of vascular endothelial growth factor and interleukin‐10 was drastically down‐regulated in favour of interferon‐γ production. Peritoneal macrophages and tumour‐associated macrophages of ZA‐treated mice recovered a full M1 antitumoral phenotype, as shown by nuclear translocation of nuclear factor kB, inducible nitric oxide synthase expression and nitric oxide production. These data indicate that clinically achievable doses of ZA inhibit spontaneous mammary cancerogenesis by targeting the local microenvironment, as shown by a decreased tumour vascularization, a reduced number of tumour‐associated macrophages and their reverted polarization from M2 to M1 phenotype.

Modulating protein ubiquitination via proteasome inhibition represents a promising target for cancer therapy, because of the higher sensitivity of cancer cells to the cytotoxic effects of proteasome inhibition. Here we show that CEP-18770 is a novel orally-active inhibitor of the chymotrypsin-like activity of the proteasome that down-modulates the nuclear factor-κB (NF-κB) activity and the expression of several NF-κB downstream effectors. CEP-18770 induces apoptotic cell death in multiple myeloma (MM) cell lines and in primary purified CD138-positive explant cultures from untreated and bortezomib-treated MM patients. In vitro, CEP-18770 has a strong antiangiogenic activity and potently represses RANKL–induced osteoclastogenesis. Importantly, CEP-18770 exhibits a favorable cytotoxicity profile toward normal human epithelial cells, bone marrow progenitors, and bone marrow–derived stromal cells. Intravenous and oral administration of CEP-18770 resulted in a more sustained pharmacodynamic inhibition of proteasome activity in tumors relative to normal tissues, complete tumor regression of MM xenografts and improved overall median survival in a systemic model of human MM. Collectively, these findings provide evidence for the utility of CEP-18770 as a novel orally active proteasome inhibitor with a favorable tumor selectivity profile for the treatment of MM and other malignancies responsive to proteasome inhibition.

Key Points: CLL patients harboring mutated IGHV genes but neither 11q or 17p deletion experience durable remission after frontline FCR.