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Objective: Allogeneic stem cell transplantation is a potentially curative therapy for patients with multiple myeloma. Polyclonal antithymocyte globulins (ATG) or monoclonal anti-CD52 (Alemtuzumab) are included in conditioning regimens to enhance engraftment and reduce risk of severe graft-vs-host disease. Because both agents have been reported to induce depletion of B cells, we sought to investigate their cytotoxic activity on myeloma cells. Materials and Methods: Complement-mediated and complement-independent activity of ATG-Fresenius and Alemtuzumab was investigated on four myeloma cell lines (RPMI-8226, U266, KMS-12-BM, and EJM) and bone marrow samples from six myeloma patients. Cytotoxicity was determined by staining with annexin V-fluorescein isothiocyanate and 7-amino-actinomycin D followed by flow cytometry. Results: ATG at a concentration of 500 μg mL−1 induced up to 100% and 85% complement-dependent killing of myeloma cell lines and primary myeloma samples respectively. In the absence of complement ATG still could induce up to 50% and 80% apoptosis in myeloma cell lines and primary myeloma samples, respectively. Preincubation of myeloma cells with a general caspase inhibitor abrogated ATG-induced complement-independent cell death. Alemtuzumab-mediated myeloma cytotoxicity was only observed in KMS-12-BM cells, and in none of the patient samples. Conclusion: ATG induces marked cytotoxic activity both in myeloma cell lines and in primary myeloma samples. Further elucidation of antibodies and antigens involved may pave the way for antibody-based myeloma therapy. [Copyright &y& Elsevier]

Objective: We investigated the effect of at least two cycles of bortezomib (1.3 mg/m2 intravenously, days 1, 4, 8, and 11) after dose-reduced allogeneic stem cell transplantation (SCT) on toxicity, CD3+ cells, graft-versus-host disease (GvHD), and response in patients with multiple myeloma. Methods: Eighteen patients with multiple myeloma without progressive disease were included. The proteasome inhibitor was given at median of 8 months after allografting to enhance or maintain remission status. Results: Fourteen patients (78%) completed the proposed two cycles. Four patients had to discontinue therapy due to neurotoxicity (n = 3) or gastrointestinal toxicity (n = 1). Severe grade III/IV toxicity was seen for thrombocytopenia (50%), leukopenia (17%), or neuropathy (17%), which was more often seen in patients treated concomitantly with cyclosporine (p = 0.06). The median circulating CD3+ cells decreased during treatment from 550 μL to 438 μL (p = 0.03), resulting in herpes zoster infection in three patients (17%). In three patients, a mild aggravation of existing acute or chronic GvHD of the skin, and in one patient de novo skin grade I acute GvHD was noted. In patients with measurable disease, complete remission, partial remission, and minor response was seen in 3 (30%), 5 (50%), and 2 (20%) patients, respective. Conclusion: Bortezomib after allogeneic SCT is effective but further studies are needed to balance the efficacy with potential hazards such as infectious complications, aggravation of GvHD, and neurotoxicity. [Copyright &y& Elsevier]

The major reason for treatment failure after allografting in multiple myeloma (MM) is relapse. Donor lymphocyte infusions (DLIs) are considered a valuable post-transplant strategy mainly for relapsed patients but using them to prevent relapse in MM has been reported rarely. In the present study, we examined the efficacy of prophylactic DLIs after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in myeloma patients with a long-term follow-up of more than 5 years. A total of 61 patients with MM who did not relapse or develop disease progression after allo-HSCT were treated with prophylactic DLI in an escalating fashion (overall 132 DLI procedures) to deepen remission status and prevent relapse. Overall response rate to DLI was 77%. Thirty-three patients (54%) upgraded their remission status, 41 patients (67%) achieved or maintained complete remission, and 26% achieved a molecular remission. Incidence of acute graft-versus-host disease (GVHD) grade II to IV was 33% and no DLI-related mortality was noted. After a median follow-up of 68.7 months from first DLI the estimated 8-year progression-free survival (PFS), and overall survival (OS) in a landmark analysis was 43% (95% confidence interval [CI], 28% to 57%) and 67% (95% CI, 53% to 82%), respectively, with best outcome for patients who acquired molecular remission (8-year PFS was 62% and 8-year OS was 83%). Prophylactic escalating DLI in a selected cohort of MM patients to prevent relapse after allograft resulted in a low incidence of severe GVHD and encouraging long-term results, especially if molecular remission is achieved. [ABSTRACT FROM AUTHOR]

Abstract: Within a prospective protocol, the incidence and impact of achievement of molecular remission (mCR) and high-risk cytogenetics was investigated in 73 patients with multiple myeloma (MM) after autologous (auto)–allogeneic (allo) tandem stem cell transplantation (SCT). After induction chemotherapy, patients received melphalan 200 mg/m2 before undergoing auto-SCT, followed 3 months later by melphalan 140 mg/m2 and fludarabine 180 mg/m2 before allo-SCT. Sixteen patients had high-risk cytogenetic features, defined by positive FISH for del(17p13) and/or t(4;14). Overall, 66% of the patients achieved CR or near-CR, and 41% achieved mCR, which was sustained negative (at least 4 consecutive samples negative) in 15 patients (21%), with no significant difference in incidence between the patients with high-risk cytogenetics and others (P = .70). After a median follow-up of 6 years, overall 5-year progression-free survival was 29%, with no significant difference between del 17p13/t(4;14)-harboring patients and others (24% versus 30%; P = .70). The 5-year progression-free survival differed substantially according to the achieved remission: 17% for partial remission, 41% for CR, 57% for mCR, and 85% for sustained mCR. These results suggest that auto–allo tandem SCT may overcome the negative prognostic effect of del(17p13) and/or t(4;14) and that achievement of molecular remission resulted in long-term freedom from disease. [Copyright &y& Elsevier]

Objective: To investigate post-transplant immunotherapy with escalating donor-lymphocyte infusions (DLI) and novel agents (thalidomide, bortezomib, and lenalidomide) to target complete remission (CR). Materials and Methods: Thirty-two patients with multiple myeloma who achieved only partial remission after allogeneic stem cell transplantation were treated with DLI. If no CR was achieved, one of the novel agents was added to target CR. Results: CR defined either by European Group for Blood and Marrow Transplantation criteria, flow cytometry, or molecular methods as assessed by patient-specific immunoglobulin H–polymerase chain reaction or plasma cell chimerism polymerase chain reaction was accomplished in 59%, 63%, and 50% of patients, respectively. Achievement of CR resulted in improved 5-year progressive-free and overall survival, according to European Group for Blood and Marrow Transplantation criteria (53% vs 35%; p =0.03 and 90% vs 62%; p =0.06), flow cytometry (74% vs 15%; p =0.001 and 100% vs 52%; p =0.1), or molecular methods (84% vs 38%; p =0.001 and 100% vs 71%; p =0.03). Conclusions: Our finding demonstrates the clinical relevance of posttransplantation therapies to upgrade remission, and of remission''s depth for long-term survival in myeloma patients. [Copyright &y& Elsevier]

Objective: To investigate lineage-specific chimerism of plasma cells after allogeneic transplantation by real-time PCR based on bi-allelic sequence polymorphism or, in case of female-to-male transplantation, on the detection of the DFFRY gene and to determine its value to quantify minimal residual disease in myeloma patients. Methods: Forty-eight samples from bone marrow samples and peripheral blood from 34 nonmyeloma patients were analyzed at different times after transplantation. Sixty-two samples from 22 myeloma patients were analyzed at different times after allogeneic stem cell transplantation, and results were compared with immunofixation and, in some cases, with PCR data using patient-specific primers. Results: The median chimerism for T cells at day +100 was greater than 99.9% and remained stable on day +180 and 1 year after transplantation. In contrast, the median donor plasma cell chimerism at day +100 was 95.5%, at day +180 98.6%, at day +360 99.8%, and 2 or more years after transplantation greater than 99.9%. Sensitivity of real-time PCR using human short insertion/deletion polymorphisms (SIDP) was 10-4 and in case of Y-PCR 10-5. Sequential monitoring of donor plasma cell chimerism showed that increasing and stable chimerism were associated with ongoing remission in 15 out of 16 samples (93%), and decreases in chimerism predicted relapse in 5 out of 6 patients. Conclusion: We conclude that plasma cell chimerism after allogeneic stem cell transplantation is delayed in comparison to T-cell chimerism. Sequential quantitative measurement of plasma cells after allogeneic stem cell transplantation with highly sensitive real-time PCR allows monitoring of residual host-tumor cells in patients with multiple myeloma and allows guiding adoptive immunotherapy strategies to enhance remission status and to prevent clinical relapse. [Copyright &y& Elsevier]

We evaluated prognostic factors of melphalan/fludarabine-based dose-reduced allografts in patients with multiple myeloma. From 1998 to 2002, 120 patients with multiple myeloma were treated with melphalan/fludarabine followed by allogeneic stem cell transplantation. The cumulative risk at 1 year for treatment-related mortality (TRM) was 18% (95% confidence interval [CI], 12%–28%). In a multivariate analysis, relapse after prior high-dose chemotherapy was the most significant risk factor for TRM (hazard ratio [HR], 2.80; 95% CI, 1.16–6.74; P = .02), relapse (HR, 4.14; 95% CI, 2.04–8.38; P < .001), event-free survival (HR, 3.11; 95% CI, 1.77–5.46; P < .001), and overall survival (HR, 2.69; 95% CI, 1.35–5.35; P = .005). In addition, relapse was also significantly diminished by chronic graft-versus-host disease (GVHD) in a time-dependent Cox model (HR, 0.37; 95% CI, 0.16–0.87; P = .02). At transplantation, 8% of the patients were in complete remission, whereas 27% had progressive disease. After allografting, 49% achieved complete remission, and 38% achieved partial remission. In a subgroup of patients with chemosensitivity at transplantation and no relapse after prior high-dose chemotherapy who underwent transplantation with peripheral blood stem cells (n = 46), the cumulative risk of TRM at 1 year was only 8% (95% CI, 1%–54%). The 2-year estimated event-free and overall survival was 60% (95% CI, 42%–78%) and 75% (95% CI, 59%–91%), respectively, for related donors (n = 34) and was 81% (95% CI, 59%–100%) and 92% (95% CI, 76%–100%), respectively, for unrelated donors (n = 12). [Copyright &y& Elsevier]

Lenalidomide may prevent relapses after allogeneic stem cell transplantation by promoting the immune-mediated graft-versus-tumor effect. We performed a prospective phase I/II study to define the dose-limiting toxicity and the immunologic effects of lenalidomide given early (day 100–180) after allograft for four cycles in patients with multiple myeloma. According to the Fibonacci design, 24 patients with a median age of 53 years were included. Dose-limiting toxicity was organ toxicity owing to graft-versus-host disease, and the maximum tolerable dose was 5 mg. The incidence of graft-versus-host disease after lenalidomide was 38%, occurring after a median of 22 days, and was beside organ toxicity, a leading cause to discontinue the study in 29% of the patients. Immune monitoring revealed a significant increase in peripheral γ-interferon–secreting CD4+ and CD8+ T cells within the first week of lenalidomide treatment followed by a delayed increase in T regulatory cells. Furthermore, natural killer (NK) cells isolated from the peripheral blood of patients evidenced a significantly improved antimyeloma activity after lenalidomide treatment. The immune effect might have contributed to the increased CR rate from 24–42% after lenalidomide treatment because nonresponding patients showed significantly less natural killer and T cell activation. (Study registered under: NCT 00778752.) [ABSTRACT FROM AUTHOR]