Cyclophosphamide and Bortezomib With Prednisone or Dexamethasone for the Treatment of Relapsed and Refractory Multiple Myeloma.

INTRODUCTION: Cyclophosphamide, bortezomib, and prednisone (CyBorP) is a highly effective, well-tolerated regimen in relapsed/refractory multiple myeloma. CyBorP, originally developed at our center to include weekly bortezomib (Bor) and alternate-day prednisone (P), was recently modified so that weekly dexamethasone (D) replaced prednisone. PATIENTS AND METHODS: To assess the effectiveness and tolerability of CyBorP/D in real-world practice, we identified 96 relapsed/refractory patients who received ≥ 1 28-day cycle of CyBorP/D, consisting of cyclophosphamide 300 mg/m(2) (days 1, 8, 15, and 22), Bor 1.0 to 1.5 mg/m(2) (days 1, 8, and 15), and either P 50 to 100 mg on alternate days or D 20 to 40 mg weekly between 2007 and 2013. RESULTS: Sixty-six (69%) patients achieved ≥ partial response: 16 with clinical complete response and 25 with very good partial response; 22 others had stable disease. Progression-free and overall survival for all patients were 16.2 months (95% confidence interval [CI], 7.7-20.1 months) and 26.3 months (95% CI, 21.6-81.2 months), respectively. Although 26 patients had prior Bor exposure, there was no difference in progression-free or overall survival versus Bor-naive patients. CONCLUSION: Toxicities with CyBorP/D were generally mild and manageable. New onset peripheral neuropathy was seen in 13 cases; 9 of 26 patients with pre-existing peripheral neuropathy developed worsening symptoms. No second primary malignancies were observed.

D(T)PACE as salvage therapy for aggressive or refractory multiple myeloma.

Dexamethasone ± thalidomide with infusion of cisplatin, doxorubicin, cyclophosphamide, and etoposide [D(T)PACE] is generally reserved as salvage therapy for aggressive multiple myeloma (MM) or plasma cell leukaemia (PCL) resistant to conventional therapies. The efficacy and durability of this potentially toxic regimen in this setting is unclear. We identified 75 patients who received D(T)PACE for relapsed/refractory MM at two tertiary care centres: Princess Margaret Hospital, Toronto and Mayo Clinic Arizona. At time of D(T)PACE, 16 patients had PCL and three patients had leptomeningeal disease. Patients were heavily pretreated (median three prior regimens, range 1-12; prior autologous stem cell transplant [ASCT] 33%). Overall response rate was 49% (very-good partial response 16%, partial response 33%) with stable disease in an additional 36%. Median progression-free survival (PFS) was 5·5 months (95% confidence interval [CI]:4·3-9·8); overall survival (OS) 14·0 months (95% CI:8·7-19·3). Thirty-five patients proceeded to ASCT or clinical trial, with median PFS for this subset of 13·4 months (95% CI:7·7-20·1) and OS 20·5 months (95% CI:14·8-63·8). D(T)PACE is an effective salvage therapy for heavily pretreated MM patients. Although the overall response rate of 49% in this poor prognosis cohort is reasonable, the PFS is short, suggesting the best role for D(T)PACE is in bridging to definitive therapy, such as transplantation.

Rapidity and quality of response to steroid-based induction therapy, without the addition of novel agents, does not affect post transplant outcomes in multiple myeloma.

BACKGROUND: The goal of induction in younger MM patients is to improve performance status and symptoms, enabling autologous stem cell transplantation (ASCT). It is unclear whether intensification of induction regimens improves post transplant outcomes. PATIENTS AND METHODS: We studied 178 MM patients who received conservative steroid-based induction therapy without novel agents before ASCT between 2000 and 2006 and correlated induction parameters (rapidity of response, need for salvage induction therapy, depth of response) with transplant outcomes. RESULTS: Fifty-three percent of patients achieved at least a partial response by cycle 2 (early responders). Rapidity of induction response did not translate into a significant difference in post transplant progression-free survival (PFS) (20.7 vs. 20.0 months; P = .24) or overall survival (OS) (64.4 vs. 51.3 months, respectively; P = .13). In 41 patients (23%) the first induction regimen failed, but they responded to salvage and proceeded to ASCT. They had inferior PFS (15.6 vs. 21.8 months; P = .008) and OS (43.5 vs. 69.4 months; P = .0004) post transplant compared with those requiring 1 regimen. CONCLUSION: Rapid response to induction therapy does not correlate with PFS or OS post ASCT when using a conservative steroid-based induction regimen. Patients in whom this initial induction fails have worse post transplant outcomes, thus the upfront use of intensive therapies with novel agents should be considered.

Molecular target characterization and antimyeloma activity of the novel, insulin-like growth factor 1 receptor inhibitor, GTx-134.

PURPOSE: Therapeutic strategies that target insulin-like growth factor 1 receptor (IGF-1R) hold promise in a wide variety of cancers including multiple myeloma (MM). In this study, we describe GTx-134, a novel small-molecule inhibitor of IGF-1R and insulin receptor (IR) and characterized its antitumor activity in preclinical models of MM. EXPERIMENTAL DESIGN: The activity of GTx-134 as a single agent and in combination was tested in MM cell lines and primary patient samples. Downstream effector proteins and correlation with apoptosis was evaluated. Cytotoxcity in bone marrow stroma coculture experiments was assessed. Finally, the in vivo efficacy was evaluated in a human myeloma xenograft model. RESULTS: GTx-134 inhibited the growth of 10 of 14 myeloma cell lines (<5 µmol/L) and induced apoptosis. Sensitivity to GTx-134 correlated with IGF-1R signal inhibition. Expression of MDR-1 and CD45 were associated with resistance to GTx-134. Coculture with insulin-growth factor-1 (IGF-1) or adherence to bone marrow stroma conferred modest resistance, but did not overcome GTx-134-induced cytotoxicity. GTx-134 showed in vitro synergies when combined with dexamethasone or lenalidomide. Further, GTx-134 enhanced the activity of PD173074, a fibroblast growth factor receptor 3 (FGFR3) inhibitor, against t(4;14) myeloma cells. Therapeutic efficacy of GTx-134 was shown against primary cells and xenograft tumors. Although dysregulation of glucose homeostasis was observed in GTx-134-treated mice, impairment of glucose tolerance was modest. CONCLUSIONS: These studies support the potential therapeutic efficacy of GTx-134 in MM. Further, they provide a rationale for clinical application in combination with established antimyeloma treatments and novel targeted therapies.

Genomic aberrations and survival of patients with light-chain-only multiple myeloma undergoing autologous stem cell transplantation.

The majority of patients with multiple myeloma (MM) have intact immunoglobulin, but in a subset of patients (∼15%), their tumors produce monoclonal light chains only (LCO). Although specific genomic aberrations have emerged as a major prognostic factor in MM, their incidence and prognostic impact on LCO myeloma patients are not clear. We therefore investigated a cohort of 86 LCO MM cases diagnosed and treated with autologous stem cell transplantation at our institution. Overall, genomic risk factors del(13q), del(17p), t(4;14), 1p loss, and 1q21 gain were detected by cytoplasmic fluorescence in situ hybridization (cIg-FISH) in 40.6%, 18.5%, 11.9%, 18.8%, and 25% of the cases, respectively. Patients with del(13q) and 1q gains had a significantly shorter overall survival (OS) (median 80.4 vs 56.2 months, P = .021; median 77.9 vs 26.9 months, P = .006, respectively) and shorter progression-free survival (PFS) (median 33.4 vs 15.8 months, P = .002; median 33.4 vs 19.1 months, P = .011, respectively) than those without the genetic abnormalities. In addition, 1p loss was significantly associated with shorter PFS (median 37.9 vs 18.2 months, P = .001). There was no significant difference in PFS or OS in patients with or without t(4;14) or del(17p). On multivariate analysis, del(13q) was an independent prognostic factor for PFS and OS.

Impact of cytogenetics in patients with relapsed or refractory multiple myeloma treated with bortezomib: Adverse effect of 1q21 gains.

We investigated the influence of genetic risk factors on the clinical response to bortezomib in 85 relapsed/refractory multiple myeloma (MM) patients. Interphase cytoplasmic fluorescence in situ hybridization (cIg-FISH) detected del(13q), del(17p), del(1p21), t(4;14), and 1q21 gain in 38%, 22%, 26%, 18% and 39% of evaluable cases. Forty-nine patients (49%) responded to bortezomib with median progression free (PFS) and overall survivals (OS) of 5.0 and 12.6 months, respectively. Patients with 1q21 gain had a significantly shorter OS (5.3 months vs. 24.6 months, p=0.0006) and PFS (2.3 months vs. 7.3 months, p=0.003) than patients without such abnormality. There was no significant difference in response rate, response duration, PFS or OS for any of the other genetic risk factors tested. Multivariate analysis confirmed that 1q21 gain is an independent risk factor for PFS (p=0.03) and OS (p=0.009) of bortezomib-treated relapsed/refractory myeloma.

Impact of genomic aberrations including chromosome 1 abnormalities on the outcome of patients with relapsed or refractory multiple myeloma treated with lenalidomide and dexamethasone.

Previous literature suggests that cytogenetics may be used for risk-adapted therapy in patients with relapsed/refractory multiple myeloma (MM) treated with lenalidomide and dexamethasone. However, the significance of each abnormality is still unclear, and chromosome 1 abnormalities have yet to be studied in this population. We therefore evaluated genetic risk factors including chromosome 1q gain and 1p loss by cIg-FISH in 143 patients with relapsed/refractory MM treated with lenalidomide and dexamethasone, and correlated the genomic aberrations with patient clinical outcomes. Patients had a median of two (range 1-7) previous therapies in this cohort. A total of 119 out of 143 (83%) patients had an objective response, with median time to progression (TTP) and overall survival (OS) of 11 and 28 months, respectively. Patients with del(1p21) or del(17p) (p53) deletions had a significantly shorter TTP. OS was shorter in patients with 1p21 or 17p deletions, but did not reach statistical significance. Prior bortezomib or thalidomide treatment was associated with shorter TTP and OS. Multivariate analysis identified del(17p), del(1p21), and prior bortezomib or thalidomide therapy as independent risk factors for shorter TTP. Our data suggest that chromosome 17p and 1p21 deletions adversely impact the outcome of lenalidomide and dexamethasone treated patients with relapsed/refractory MM. Improved therapeutic strategies are required for these patients.

Prognostic relevance of 6q deletion in Waldenström's macroglobulinemia: a multicenter study.

The deletion of the long arm of chromosome 6 is the most common cytogenetic abnormality in Waldenstrom's macroglobulinemia (WM), but its prognostic significance is unclear. We investigated 77 patients with WM by interphase cytoplasmic immunoglobulin M fluorescence in situ hybridization (cIgM-FISH) and correlated the 6q status with the patients' clinical features and survival. cIg-FISH detected hemizygous 6q deletions in 32 patients (41.6%). The 6q deletions were correlated with higher C-reactive protein levels (P = .02) and CD23 expression (P = .03) but not with other clinical laboratory features of WM. There was no significant difference in time to the initial treatment between deleted and non-deleted groups (median, 5.6 months vs. 2.6 months; P = .46), or overall survivals in patients with and without del (6q) (163 months vs. not reached; P = .83). Our study confirms that the 6q deletion is a frequent event, but it does not appear to affect the clinical outcome of WM.

Influence of cytogenetics in patients with relapsed or refractory multiple myeloma treated with lenalidomide plus dexamethasone: adverse effect of deletion 17p13.

Although the combination of lenalidomide and dexamethasone is effective therapy for patients with relapsed/refractory multiple myeloma, the influence of high-risk cytogenetic abnormalities on outcomes is unknown. This subanalysis of a large, open-label study investigated the effects of the most common unfavorable cytogenetic abnormalities detected by fluorescence in situ hybridization, del(13q), t(4;14), and del(17p13), in 130 evaluable patients treated with this regimen. Whereas patients with either del(13q) or t(4;14) experienced a median time to progression and overall survival comparable with those without these cytogenetic abnormalities, patients with del(17p13) had a significantly worse outcome, with a median time to progression of 2.22 months (hazard ratio, 2.82; P < .001) and median overall survival of 4.67 months (hazard ratio, 3.23; P < .001). Improved therapeutic strategies are required for this subgroup of patients. This study was registered at www.ClinicalTrials.gov as #NCT00179647.

The Bcl-2 family protein inhibitor, ABT-737, has substantial antimyeloma activity and shows synergistic effect with dexamethasone and melphalan.

PURPOSE: The aim of this study is to investigate the antimyeloma activity of a novel Bcl-2 family inhibitor, ABT-737, in preclinical treatment of multiple myeloma. EXPERIMENTAL DESIGN: The antimyeloma activity of ABT-737 was evaluated in cultured myeloma cell lines and patient myeloma samples, and in a xenograft mouse myeloma model. Drug combination therapy using ABT-737 with other commonly used myeloma drugs was also investigated. RESULTS: MY5 and JJN3 cell lines exhibited the most sensitivity to ABT-737 with an EC(50) of 0.2 and 0.5 micromol/L, respectively, with increased cell apoptosis and elevated activated caspase-3. We identified two distinct groups of myeloma patient samples that were either sensitive or resistant to the drug. Four of 15 patient bone marrow samples (27%) were highly sensitive to ABT-737 at doses of 0.25 and 0.5 micromol/L, which eliminated 80% to 90% of myeloma cells as a result of cellular apoptosis 3 days after drug treatment. ABT-737 showed a synergistic effect when combined with dexamethasone or melphalan in inducing myeloma cell death. Furthermore, the dexamethasone-resistant MM1(Dex)R myeloma cell line was highly sensitive to 0.2 micromol/L ABT-737. As determined by colony assay, little or no detectable toxicity to patient hematologic progenitor cells was observed at 1 micromol/L ABT-737. ABT-737 dose dependently suppressed tumor growth in a xenograft MY5 mouse model. CONCLUSIONS: These studies show substantial antimyeloma activity of ABT-737 as a single agent or in combination with dexamethasone or melphalan and suggest a rationale for future clinical trials.

Bortezomib therapy response is independent of cytogenetic abnormalities in relapsed/refractory multiple myeloma.

Myeloma patients with unfavorable molecular cytogenetics have a poor prognosis irrespective of treatment with conventional chemotherapy or autologous stem cell transplant. To investigate whether bortezomib, a new proteasome inhibitor, is active in relapsed/refractory myeloma patients with genetic risk factors, we evaluated the outcome of 65 patients and correlated the clinical response with 13q deletion, translocations t(11;14) and t(4;14) and CKS1B amplification as detected by interphase cytoplasmic fluorescence in situ hybridization (cIg-FISH). Thirty-seven of 61 (61%) evaluable patients had an objective response to bortezomib with median progression free (PFS) and overall survivals (OS) of 9.5 and 15.1 months, respectively. Of 43 cases with evaluable bone marrows, cIg-FISH determination of del(13q), t(4;14), t(11;14) and CKS1B amplification was done on 40, 41, 41 and 37 cases and the frequency of their detection was 35%, 15%, 15%, and 32%, respectively. There was no statistically significant difference in response to bortezomib for patients with or without 13q deletion (77% versus 50%), t(4;14) (67% versus 56%), t(11;4) (33% versus 62%), or CKS1B amplification (67% versus 57%). Furthermore, there was no statistically significant difference in PFS or OS following bortezomib therapy between patients with or without these molecular cytogenetic abnormalities. Our data suggest that, in this pilot study, bortezomib is an effective salvage therapy for refractory/relapsed myeloma, irrespective of genetic risk factors.

Multiple myeloma patients with CKS1B gene amplification have a shorter progression-free survival post-autologous stem cell transplantation.

The prevalence and prognostic relevance of recurrent gains of CKS1B (cyclin kinase subunit 1B) gene at chromosome 1q21 region was investigated by interphase fluorescence in situ hybridisation in a cohort of 99 multiple myeloma (MM) patients treated with intensive chemotherapy followed by autologous stem cell transplantation. CKS1B amplification (3-8 CKS1B signals) was detected in 31of 99 (31%) patients and was associated with deletions of p53 (P = 0.003) and 13q (P = 0.039) but not with translocation t(11;14) or t(4;14). CKS1B amplification was associated with bone marrow plasmacytosis (P = 0.02), but there was no correlation with patient age, gender, disease stage, lytic bone lesions, albumin, creatinine, C-reactive protein or beta-2 microglobulin levels. Patients with CKS1B amplification had a significantly shorter progression-free survival than those without such amplification (18.5 vs. 25.7 months, P = 0.035). Likewise, a shorter overall survival (44.8 months vs. not reached) was observed; however, the difference did not reach statistical significance (P = 0.20). Seven patients had paired bone marrows obtained at diagnosis and at relapse, the percentage of cells with CKS1B amplification and the level of amplification were significantly increased in the relapse marrows. In this cohort of patients, CKS1B was frequently amplified in MM and may represent genetic instability associated with disease progression.

Weekly cyclophosphamide and alternate-day prednisone: an effective, convenient, and well-tolerated oral treatment for relapsed multiple myeloma after autologous stem cell transplantation.

OBJECTIVE: To assess the efficacy and tolerability of weekly oral cyclophosphamide in combination with alternate-day prednisone (CP) as salvage therapy for patients with relapsed multiple myeloma (MM) after autologous stem cell transplantation (ASCT). PATIENTS AND METHODS: We retrospectively reviewed the medical records of all patients identified in our clinical database as having received CP as treatment for relapsed MM after ASCT at Princess Margaret Hospital between July 1998 and May 2004. The CP regimen consisted of oral cyclophosphamide at 500 mg once weekly and oral prednisone at 100 mg on alternate days. RESULTS: A total of 66 patients received the CP regimen, with a median of 2.0 prior therapies (range, 1.0-5.0) from time of diagnosis to initiation of CP. The median time from relapse after ASCT to start of CP therapy was 1.5 months (range, 0.0-23.5 months). Because of nonsecretory disease in 7 patients, only 59 patients were evaluable for response. The median duration of CP treatment was estimated at 5.8 months (95% confidence interval [CI], 4.6-7.8 months). With a median follow-up of 15.9 months (range, 1.4-67.2 months), 36 patients (61%) responded to treatment, 24 (41%) of whom had a partial response. The 1-year progression-free survival of all evaluable patients was estimated at 66% (95% CI, 54%-80%), with a median progression-free survival of 18.6 months (95% CI, 13.9-29.9 months). The median overall survival from time of initiation of CP was estimated at 28.6 months (95% CI, 22.1-not available months). CONCLUSION: Our data show that CP is an effective, well-tolerated, and convenient regimen as salvage therapy for MM after ASCT.

Clinical outcomes in t(4;14) multiple myeloma: a chemotherapy-sensitive disease characterized by rapid relapse and alkylating agent resistance.

PURPOSE: To determine whether primary drug resistance or rapid relapse explains the poor prognosis seen in t(4;14)-positive multiple myeloma (MM). PATIENTS AND METHODS: A total of 131 patients treated with high-dose therapy (HDT) were assessed, of whom 19 were t(4;14) positive. We examined the presentation features, chemotherapy responsiveness at presentation and to salvage therapies at relapse, and overall survival outcomes. RESULTS: t(4;14)-positive patients had a predominance of the immunoglobulin A isotype (52.6%) but otherwise baseline characteristics were indistinguishable. After treatment with vincristine, doxorubicin, and dexamethasone or dexamethasone alone, 17 (89.7%) of the 19 patients achieved a partial response and 11 patients (57.9%) demonstrated an additional 50% reduction in paraprotein after HDT. Thus, t(4;14)-positive patients are chemotherapy sensitive; however, early progression was common, with 26% of patients progressing before HDT and a median progression-free survival after HDT of only 14.1 months. At relapse, a resistance to alkylating agents was evident, with no responses (zero of 11 patients) seen with conventional-dose alkylating agents. Salvage regimens using thalidomide and/or dexamethasone achieved at least minimal response in 59% of patients. The duration of response was short, however, with a median of only 4.7 months. The median overall survival after HDT was 24.2 months. CONCLUSION: We conclude that t(4;14)-positive MM is chemotherapy sensitive but rapid relapse occurs. Resistance to alkylating agents is evident at relapse. The development of novel therapeutic agents is required, including the early clinical study of targeted fibroblast growth factor receptor 3 tyrosine kinase inhibitors, which have shown promise in preclinical studies.

The SH3-SAM adaptor HACS1 is up-regulated in B cell activation signaling cascades.

HACS1 is a Src homology 3 and sterile alpha motif domain-containing adaptor that is preferentially expressed in normal hematopoietic tissues and malignancies including myeloid leukemia, lymphoma, and myeloma. Microarray data showed HACS1 expression is up-regulated in activated human B cells treated with interleukin (IL)-4, CD40L, and anti-immunoglobulin (Ig)M and clustered with genes involved in signaling, including TNF receptor-associated protein 1, signaling lymphocytic activation molecule, IL-6, and DEC205. Immunoblot analysis demonstrated that HACS1 is up-regulated by IL-4, IL-13, anti-IgM, and anti-CD40 in human peripheral blood B cells. In murine spleen B cells, Hacs1 can also be up-regulated by lipopolysaccharide but not IL-13. Induction of Hacs1 by IL-4 is dependent on Stat6 signaling and can also be impaired by inhibitors of phosphatidylinositol 3-kinase, protein kinase C, and nuclear factor kappaB. HACS1 associates with tyrosine-phosphorylated proteins after B cell activation and binds in vitro to the inhibitory molecule paired Ig-like receptor B. Overexpression of HACS1 in murine spleen B cells resulted in a down-regulation of the activation marker CD23 and enhancement of CD138 expression, IgM secretion, and Xbp-1 expression. Knock down of HACS1 in a human B lymphoma cell line by small interfering ribonucleic acid did not significantly change IL-4-stimulated B cell proliferation. Our study demonstrates that HACS1 is up-regulated by B cell activation signals and is a participant in B cell activation and differentiation.

Soluble interleukin-13Ralpha2 decoy receptor inhibits Hodgkin's lymphoma growth in vitro and in vivo.

Recent studies have demonstrated that the malignant Reed-Sternberg cells of Hodgkin's lymphoma (HL) secrete and are responsive to interleukin (IL)-13. We hypothesized that overexpression of a soluble IL-13 decoy receptor (sIL-13Ralpha2) via adenoviral-mediated gene transfer would inhibit IL-13-induced Reed-Sternberg cell proliferation. Western blot and ELISA analysis verified expression of sIL-13Ralpha2 in cell lysates and supernatants of AdsIL-13Ralpha2-transduced COS-7 cells. Treatment of two IL-13-responsive HL-derived cell lines, HDLM-2 and L-1236, with AdsIL-13Ralpha2-conditioned medium, resulted in the inhibition of cell proliferation, and down-regulated the phosphorylation of signal transducer and activator of transcription 6 (STAT6), an important mediator of IL-13 signaling. i.v. delivery of AdsIL-13Ralpha2 in NOD/SCID mice with s.c. implanted HDLM-2 cells delayed tumor onset and growth while enhancing survival compared with control mice. Intratumoral administration of AdsIL-13Ralpha2 led to the regression or stabilization of established tumors and was associated with diminished STAT6 phosphorylation. Our data demonstrate that AdsIL-13Ralpha2 can suppress HL growth in vitro and in vivo.