Sequential Administration of Bortezomib, Liposomal Doxorubicin and Dexamethasone (BDD) Followed by Thalidomide and Dexamethasone (TD) Results in Rapid Control of Untreated High-Risk Multiple Myeloma (MM) and Improves Depth of Response

Abstract Background: Doxorubicin and dexamethasone followed by thalidomide and dexamethasone is an effective, well-tolerated regimen for pts with MM. We previously reported an overall response rate (ORR) of 90.5%, with 35% achieving nCR/CR in 45 newly diagnosed pts, the majority of whom were ISS I (62%). Despite similar ORR, a survival analysis demonstrated inferior outcomes for pts with ISS II, ISS III or softtissue involvement by disease. Based on our experience, we designed a phase II study incorporating bortezomib and liposomal doxorubicin into the upfront treatment of pts with high-risk MM (ISS II, III or ISS I with soft-tissue disease). The aims of the study were to determine the safety and efficacy of bortezomib, pegylated doxorubicin and dexamethasone followed by thalidomide and dexamethasone (with or without bortezomib) in pts with untreated poor-risk or primary refractory MM. We correlated disease response with PET response to determine if there was concordance (or discordance) in these pts. Methods: 34 pts with high-risk MM have been enrolled. Treatment includes BDD (bortezomib 1.3mg/m2 IV days 1, 4, 8, and 11, liposomal doxorubicin 30mg/m2 IV on day 4, and dexamethasone 20mg PO on the day of and the day after bortezomib) for three 21-day cycles followed by 2 cycles of TD (thalidomide 200mg PO daily and dexamethasone 40mg PO on days 1–4, 9–12, 17–20) every 28 days for patients achieving at least PR, or BTD (less than a PR after BDD). Prophylactic use of acyclovir, fluconazole, and pyridoxine was implemented throughout the study. Aspirin 81mg or low molecular weight heparin (in patients with increased risk for VTE) was mandated during the TD portion of the study. Response was assessed using International Myeloma Working Group (IMWG) uniform response criteria. PET scans were performed at baseline, following BDD and at end of study (EOS) to determine the role of functional imaging in pts with high-risk MM. Results: At the time of this analysis, 28 pts have completed study and are evaluable. Baseline characteristics include median age of 58 years (range 41–80), 61% male, 43% (12/28) ISS II, 46% (13/28) ISS III, and 11% (3/28) ISS I with soft-tissue disease. Sixty-four percent of pts have abnormal cytogenetics: 39% (11/28) del 13q, 11% (3/28) t(4;14) and 7% (2/28) loss of p53 gene. Following BDD (1–3 cycles) the ORR was 79% with 25% CR/nCR and 36% ≥VGPR. At the EOS, the ORR remained 79%, however there is a significant improvement in the quality of response with 43% of pts achieving CR/nCR (p = 0.03) and 61% ≥VGPR (p = 0.008). Only 1 pt progressed on study based on skeletal survey findings despite achieving a serologic VGPR and improving clinically. Poor-risk cytogenetics (del 13q, t (4;14) or loss of p53) or soft-tissue disease did not affect response (p = 0.20 and p = 1.0, respectively). Of 11 pts with del 13q, 82% had ≥VGPR. Of the 5 pts with t (4;14) or loss of p53, 100% achieved ≥VGPR. There was poor agreement between EOS and PET response in the 19 pts who had PET data available, Kappa 0.11. The majority of pts (15/19) had PR by PET and 3 pts had SD. In the only pt that had progression by PET, IMWG response was VGPR and biopsy confirmed granulomatous disease rather than MM. Grades 3/4 neutropenia and thrombocytopenia occurred in 18% and 36% of pts, respectively. The incidence of neuropathy was 28%, but was grade 3 in only 1 pt (4%). Five pts developed DVT. Two pts developed asymptomatic decline in LVEF that improved with medical therapy. Fifty-seven percent of pts (16/28) have had successful stem cell harvest and have undergone ASCT. Three more pts have ASCT planned. Conclusions: BDD followed by TD (or BTD) results in rapid disease control with manageable toxicity in a poor-risk group of pts with MM. The depth of response is significantly improved with the sequential administration of novel agents, as has been demonstrated by other investigators (Jagannath ASH 2007). The 79% ORR is modest, however the ≥61% VGPR and 43% nCR/CR rates seen in these very high risk pts are comparable to initial therapy with VTD and Rev/Vel/Dex (Rajkumar ASH 2007 and Richardson ASH 2007, respectively) and are encouraging. High-quality responses were seen independent of cytogenetic abnormalities or the presence of soft-tissue disease. BDD followed by TD represents a promising therapeutic option for these pts. PET response does not correlate with IMWG response, perhaps due to the high sensitivity and lack of specificity of functional imaging

High Dose Chemotherapy and Autologous Stem Cell Transplantation with Melphalan in Patients with Monoclonal Immunoglobulin Deposition Disease Associated with Multiple Myeloma

Abstract Introduction: Monoclonal immunoglobulin deposition disease (MIDD) includes several disorders that are characterized by the deposition of serum monoclonal gamma-globulins in various organs, most notably in the kidney resulting in renal dysfunction. There is no standard therapy for MIDD. We report our experience with high dose chemotherapy and autologous peripheral blood stem cell transplantation (HDC/ASCT) in patients with MIDD associated with underlying multiple myeloma (MM). Methods: We have done a retrospective analysis of patients seen at MSKCC with biopsy proven MIDD associated with MM and who underwent HDC/ASCT between 2002 and 2007. Results: Seven patients, all male with a median age of 46, had MM and MIDD. Five had Light Chain Deposition Disease (LCDD), 1 Light and Heavy Chain Deposition Disease (LHCDD), and 1 Light Chain Crystal Deposition Disease (LCCDD). All were stage IB by Durie-Salmon classification. Bone marrow plasmacytosis was a median of 21% (range 10 to 41%). Serum immunofixation showed an IgG kappa monoclonal band in only 2 patients while serum protein electrophoresis showed a monoclonal spike in only 1 of the 2. A monoclonal kappa light chain was detected by serum Free Light Chain Assay in all 7 patients. The diagnosis of MIDD was confirmed by immunofluorescence staining and electron-microscopy examination of kidney biopsy specimens in all patients. Three patients were dialysis dependent before HDC/ASCT. All patients received Melphalan 140 mg/m2 followed by peripheral blood stem cell rescue. The treatment was well tolerated with no mortality and no unexpected morbidity. This treatment modality was effective in controlling the underlying plasma cell dyscrasia and light chain production as six patients achieved complete hematologic remission (CR, by EORTC criteria) post-transplantation and remain in CR after a median follow up of 18.6 months (2.9 to 64.8 months). One patient achieved partial remission (PR). The median progression free survival has not been reached but the patient with a PR had progression of his MM and is currently receiving second-line therapy. Among the 4 patients who were dialysis independent at the time of HDC/ASCT, the renal function has improved compared to pre-HDC/ASCT in 2, remained stable in 1 (who achieved hematologic PR), and worsened in 1 leading to hemodialysis despite hematologic CR. Among the three patients who were dependent on hemodialysis at the time of HDC/ASCT, 2 have undergone kidney transplantation 14.1 and 45.7 months after HDC/ASCT and have a normal creatinine clearance 30.9 and 64.8 months after HDC/ASCT, respectively. The third patient remains in hematologic CR but has resumed peritoneal dialysis after a two-month-period of dialysis independence post-HDC/ASCT. He is currently being evaluated for kidney transplantation. Conclusions: Our results corroborate previous encouraging but limited experience with HDC/ASCT in MIDD and compare favorably with historical reports of conventional therapy in this patient population. These results also argue in favor of kidney transplantation in patients who achieve a hematologic CR after HDC/ASCT for MM associated with MIDD

Subcutaneous or Intravenous Administration of Romiplostim in Thrombocytopenic Patients With Lower Risk Myelodysplastic Syndromes

BACKGROUND: Romiplostim is a peptibody protein that augments thrombopoiesis by activating the thrombopoietin receptor. METHODS: In this phase 2, multicenter, open-label study, 28 thrombocytopenic patients with lower risk myelodysplastic syndromes (MDS) were assigned to receive romiplostim 750 mu g administered subcutaneously either weekly or biweekly or administered as biweekly intravenous injections for 8 weeks. Patients also could enter a 1-year study extension phase. RESULTS: At least 1 adverse event was observed in 93% of patients. The most common adverse events were fatigue and headache (18% for both, and 5 events were grade 3 or 4. There was 1 serious treatment-related adverse event in the biweekly intravenous cohort (hypersensitivity). This hypersensitivity resolved without discontinuation of study treatment. No patients developed neutralizing antibodies or bone marrow fibrosis. Of the patients who completed 8 weeks of treatment, 57% had a complete platelet response, an additional 8% had a major platelet response, and 61% did not require a platelet transfusion during this period. Weekly subcutaneous injections achieved the highest mean trough concentrations. CONCLUSIONS: The safety and efficacy profiles of romiplostim in this study suggested that weekly subcutaneous administration of 750 jig romiplostim is an appropriate starting dose for future clinical studies in patients with MDS and thrombocytopenia. Cancer 2011;117:992-1000. (C) 2010 American Cancer Society

Phase 1/2 Study of AMG 531 in Thrombocytopenic Patients (pts) with Low-Risk Myelodysplastic Syndrome (MDS): Update Including Extended Treatment

Abstract Background: AMG 531 is a novel thrombopoiesis-stimulating peptibody that is being studied for its ability to increase platelet production by stimulating the thrombopoietin receptor. This report updates outcomes in Part A of the study as of May 2007 on pts who continued into the extension phase of this ongoing phase 1/2, open-label, sequential-cohort, dose-escalation study to evaluate the safety and efficacy of AMG 531 in low risk MDS pts with severe thrombocytopenia (Kantarjian et al., ASCO, 2007). Methods: Pts with low- risk MDS (IPSS Low or Intermediate-1, excluding CMML), a mean baseline platelet count ≤50×109/L, and only receiving supportive care were eligible to enter this study. Pts were enrolled into sequential cohorts of 300, 700, 1000, and 1500μg, receiving 3 weekly subcutaneous injections of AMG 531. After evaluation of platelet response at week 4, pts could continue AMG 531 in an optional treatment extension at their assigned dose or dose adjust to achieve or maintain a response. Results: The mean duration of exposure to AMG 531 was 23±15.5 (SD) weeks. Of 44 pts enrolled, 40 continued into the extension phase; 16 pts remain on treatment. Eighteen pts (41%) achieved a durable platelet response (per IWG 2006 criteria for at least 8 consecutive weeks). Evaluation of durable responses based on baseline platelet count showed that responses occurred in 12/29 (41%) pts with a baseline count of ≥20×109/L, and in 6/15 (40%) pts with a baseline count of <20×109/L. The mean duration of the platelet response was 22.8±13.3 (SD) weeks. A total of 104 platelet transfusions were given to 17/44 (39%) pts during this study; of these transfusions, 7 were given in 3/18 (17%) pts who achieved a durable response. Treatment-related AEs were reported in 17 pts. There were 3 deaths unrelated to treatment. Two confirmed cases of transformation to AML were reported. These two pts received maximum doses of 300 and 1000μg. Six pts were confirmed to have temporary blast cell increases, three of whom had increases above 20%. Of the 6, 4 were receiving 1500μg and 2 were receiving 1000μg. In all 6 pts, blast cell counts were observed to have fallen upon follow-up assessments within 7 weeks after treatment discontinuation. In one case, treatment was reinitiated at 700μg. Conclusions: In this study, AMG 531 appeared to be well-tolerated in severely thrombocytopenic low-risk MDS pts, and resulted in increased and sustained platelet counts in the responding pts. AMG 531 may have a role in the treatment of low-risk MDS pts who are thrombocytopenic or have a history of bleeding. These data suggest that further exploration is merited in this pt population. Pt recruitment is ongoing until reaching the planned 84 pts

CD32B is highly expressed on clonal plasma cells from patients with systemic light-chain amyloidosis and provides a target for monoclonal antibody–based therapy

Despite advances in therapy, many patients with systemic light-chain amyloidosis (AL) die within 3 years from diagnosis. The humanized 2B6 monoclonal antibody (MoAb) is specific for the low-affinity IgG Fc receptor CD32B and effective in a human CD32B+ B-cell lymphoma murine xenograft model. Because MoAb therapy could improve outcomes in AL, we studied CD32B expression by clonal plasma cells obtained from 48 patients with AL. Transcript profiling showed that expression of CD32B was significantly higher than expression of all other Fc receptor family members. Reverse-transcriptase polymerase chain reaction (RT-PCR) using double-enriched CD138+ plasma cells showed uniform expression of the stable cell surface CD32B1 isoform at diagnosis and relapse, and flow cytometry showed intense CD32B cell surface staining on 99% of CD138+ plasma cells at diagnosis and relapse. These data provide a rationale for the novel therapeutic targeting of CD32B using the humanized 2B6 MoAb in patients with systemic AL-amyloidosis

CD32B Expression Reflects Phenotypic and Functional Heterogeneity in Multiple Myeloma (MM)

Abstract Intraclonal heterogeneity (IH) in MM may provide a basis for the selection of resistance to therapy that occurs over time. Model systems to study IH in MM have not been defined so we focused on the expression of CD32B, the low-affinity inhibitory Fcγ-receptor that is a key participant in normal plasma cell apoptosis and a potential target for monoclonal antibody therapy. At diagnosis, CD138+ MM marrow cells are largely CD32B+ (n=72; median 94%, range 1–100) while at relapse the CD32B+ MM subpopulation is significantly smaller in both bone marrow (n=25, median 83%, (10–100), P = 0.02) and extramedullary sites (n=8, median 17% (0–78); P << 0.01). Among human MM cell lines only two of ten tested expressed cell-surface CD32B. We hypothesize that the CD32B phenotype of MM subpopulations contributes to the functional heterogeneity that is critical to the selection of resistance, and sought a model system to study CD32B-related IH. The KMS-12BM cell line (BM), a human MM line from marrow, has CD32B+ and CD32B− subpopulations as MM marrows do, while the KMS-12PE cell line (PE), from the pleural fluid of the same patient, is completely CD32B negative, as is often the case in extramedullary MM. Both BM and PE cells share t(11;14), del 17p and other cytogenetic abnormalities, and both contain intact CD32B genes (FCGR2B). We used 3 populations, BM CD32B+, BM CD32B− and PE (CD32B−), as well as sorted patient MM cells, to study the IH associated with CD32B. RNAi studies demonstrated that the expression of FCGR2B in BM cells is dependent on the Ets family transcription factor PU.1, while PE cells do not express PU.1. RT-PCR of patient MM cells sorted into paired CD32B+ and CD32B− fractions showed PU.1 and FCGR2B (CD32B) expression only in CD138+/CD32B+ cells. Cell-tracking studies with CFSE showed that BM CD32B+ cells gave rise to BM CD32B− cells but that the reverse did not occur. Cell-culture studies showed that BM CD32B+ cells have significantly lower apoptotic rates than BM CD32B− cells, while the latter display greater dependence on insulin for survival and on IGF-1 and MIP-1α for proliferation. In order to better understand the differences between CD32B+ and CD32B− populations, we performed transcript profiling. BM CD32B+ cells have significantly higher expression of the activin inhibin, while BM CD32B− cells overexpress insulin-response genes such as the kinase Akt2. Compared to BM cells, PE cells overexpress germ-cell transcription factors and inflammasome-related genes, while BM cells overexpress tetraspanins (CD9, CD37, CD53) and insulin-response genes. Of interest, there are also significant differences in the expression of BMP and Wnt-related genes (but not Hh or Notch genes). BM cells overexpress BMPR1A, FZD2 and Wnt5A while PE cells overexpress CRIM1, FZD1 and LEF1. These data indicate that functional IH exists in MM, that the KMS-12 cell lines provide a useful model for its study, and that MM may originate in a CD32B+ cell that begets CD32B− heirs. We continue to study PU.1 and the generation of CD32B− cells by CD32B+ cells; to validate transcript data using sorted patient specimens; and to assess with RNAi the contributions of BMP, Wnt and insulin-response genes to the survival and proliferation of CD32B+ and CD32B− cells, seeking novel therapeutic targets on which selection of resistance may depend

CD32B on Clonal Plasma Cells in Systemic Light-Chain Amyloidosis (AL) and Multiple Myeloma (MM): A Target for Immunotherapy in Both Disorders and a Prognostic Marker in MM

Abstract Despite stem cell transplant and new therapies, nearly all patients with AL and MM die of disease or complications of treatment. Novel approaches that selectively kill clonal plasma cells are needed. CD32B, the inhibitory Fcγ receptor IIB, is a member of the Fc receptor (FcR) family on chromosome 1q. B-cells and some monocytes and dendritic cell subtypes express cell-surface CD32B, which has a cytoplasmic inhibitory motif important in regulating immune responses. Unlike the CD32B2 isoform on myeloid cells, CD32B1 on B-cells is not internalized, making it a suitable target for monoclonal antibody (MAb) therapy (Blood 2006Jun6 Epub). CD32B has not previously been found on AL and MM plasma cells. We used purified CD138+ marrow and blood cells from AL, MM and plasma cell leukemia (PCL) patients, and 5 human MM cell lines, to evaluate CD32B gene and cell-surface expression with gene expression profiles (GEP) (Affymetrix U133 PLUS 2.0), RT-PCR for CD32B1 and B2, and flow-cytometry with the 2B6 MAb for CD32B. In AL, GEP showed that CD32B expression was significantly higher than other FcR genes (p98% of all AL plasma cells. In MM, public GEP data (http://lambertlab.uams) showed that CD32B expression was significantly higher than other FcR genes while RT-PCR showed CD32B1 message in CD138+ MM and PCL specimens but not in the RPMI 8226 cell line. Cytogenetic analysis then showed that 8226 cells lack t(4;14) but have 4 copies of 1q, implicating segmental uniparental tetrasomy of a mutant allele in the lack of CD32B message. Flow cytometry showed median 96% CD32B expression on CD138+ marrow cells from patients with normal or hyperdiploid cytogenetics, but significantly lower expression (median 69%, p=0.01) in patients with unfavorable cytogenetics (del 13, t(4;14)). CD32B expression was lower still on PCL specimens (median 10%) and nil on MM cell lines. We then investigated the GEP of sorted CD138+/CD32B+ and CD32B− fractions from MM patients. In CD138+/CD32B+ cells, CD45C and CXCR4 were overexpressed. In CD138+/CD32B− cells, genes on chromosome 1q were overexpressed, including those for cancer testis antigens and others possibly associated with biologic aggressivity (Cancer Cell2006;9:313). Notably, the CD32B-specific MAb 2B6 directs human mononuclear cell cytotoxicity against CD32B+ cell lines, reduces tumor growth and improves tumor-free survival in a mouse xenograft model. Moreover, an Fc-engineered humanized variant of 2B6 elicits ADCC-mediated specific cytotoxicity against a low-level CD32B+ MM cell line in vitro. In sum, these data show that CD32B is important in AL and MM; that CD32B on AL and the majority of MM plasma cells provides a target for MAb therapy; and that, given the results in MM, PCL and MM cell lines, CD32B expression is inversely related to biologic aggressivity. Genetic instability of chromosome 1q may provide a direct basis for this relationship thereby mechanistically linking CD32B expression in MM to prognosis. These data support further evaluation of CD32B and clinical studies of anti-CD32B MAb therapy in AL and MM

Safety and Efficacy of Romiplostim in Patients With Lower-Risk Myelodysplastic Syndrome and Thrombocytopenia

Purpose To assess the safety and efficacy of romiplostim, a peptibody that increases platelet production, for treatment of thrombocytopenic patients with myelodysplastic syndromes (MDS). Patients and Methods Eligible patients had lower-risk MDS (International Prognostic Scoring System low or intermediate 1), a mean baseline platelet count ≤ 50 × 10 9 /L, and were only receiving supportive care. Patients received three injections of 300, 700, 1,000, or 1,500 μg romiplostim at weekly intervals. After evaluation of platelet response at week 4, patients could continue to receive romiplostim in a treatment extension phase for up to 1 year. Results All 44 patients who enrolled completed the treatment phase; 41 patients continued into the extension phase. Median platelet counts increased throughout the study, from fewer than 30 × 10 9 /L at baseline to 60, 73, 38, and 58 × 10 9 /L at week 4 for the 300-, 700-, 1,000-, and 1,500 -μg dose cohorts, respectively. A durable platelet response (per International Working Group 2000 criteria for 8 consecutive weeks independent of platelet transfusions) was achieved by 19 patients (46%). The incidence of bleeding events and platelet transfusions was less common among patients who achieved a durable platelet response than those who did not (4.3 v 39.3 per 100 patient-weeks). Forty-three patients (98%) reported one or more adverse events. Treatment-related serious adverse events were reported in five patients (11%), all of whom were in the 1,500-μg dose cohort. Two patients progressed to acute myeloid leukemia during the study. No neutralizing antibodies to either romiplostim or endogenous thrombopoietin were seen. Conclusion Romiplostim appeared well-tolerated in this study and may be a useful treatment for patients with MDS and thrombocytopenia