Treatment Of Advanced Multiple Myeloma Research Articles

FT576: A Novel Multiplexed Engineered Off-the-Shelf Natural Killer Cell Immunotherapy for the Dual-Targeting of CD38 and Bcma for the Treatment of Multiple Myeloma

Multiple myeloma (MM) is a B cell neoplasm that originates from the malignant transformation of plasma cells, with treatment strategies that include chemotherapeutic agents and immunomodulatory drugs. Recently, significant effort has been applied to the development of monoclonal antibody (mAb) and chimeric antigen receptor (CAR) T cell therapies for the treatment of advanced MM. Anti-CD38 mAb therapy is at the forefront of these efforts, with clearly demonstrated clinical benefit and availability of a FDA-approved mAb in daratumumab. Antibody-dependent cellular cytotoxicity (ADCC) is a key mechanism of action of CD38-targeted mAbs; however, high CD38 expression on natural killer (NK) cells results in fratricide, which depletes the NK cells necessary for ADCC. In addition to CD38, targeting of other MM-associated cell-surface proteins has been explored. Of these antigens, the TNF-superfamily member BCMA is among the most researched and is under development by multiple groups as a CAR target. Several clinical trials in MM have shown promising initial results targeting BCMA with CAR T cells, however there remains significant opportunity to improve both relapse rates and treatment of relapsed patients. Collectively, clinical data would suggest that combinatorial targeting of both CD38 and BCMA may improve clinical efficacy compared with targeting either antigen alone. We have developed a multiple-target, adoptive NK cell immunotherapy approach for the treatment of MM. The strategy utilizes our off-the-shelf NK cell platform with four engineered attributes: 1) an anti-BCMA CAR for direct MM targeting, 2) high affinity non-cleavable CD16 (hnCD16) for enhanced ADCC in combination with anti-CD38 mAbs, 3) CD38 deletion for resistance to anti-CD38 mAb induced NK cell depletion, and 4) IL-15/IL-15 receptor α fusion protein (IL-15RF; IL-15 fused to IL-15Rα) for enhanced NK cell persistence. The anti-BCMA CAR consists of a unique single chain variable fragment (scFv) targeting domain with a BCMA binding affinity in the low nanomolar range, providing high functional avidity and efficacy in disease settings where BCMA antigen density is low. Our approach utilizes NK cells derived from a genetically engineered, clonally-derived master pluripotent stem cell line with uniform expression of anti-BCMA CAR, IL-15RF, hnCD16, and CD38 bi-allelic knockout. The engineered master pluripotent stem cell line serves as the starting material for consistent and repeatable manufacture of off-the-shelf NK cells that contain all described attributes in a homogenous manner (termed FT576) and that can be produced at a scale to support multi-dose treatment strategies and on-demand dose availability. In preclinical studies, FT576 NK cells exhibited uniform expression of CD16, CAR, and IL15-RF and did not express CD38 (<1%). In an in vitro fratricide assay, FT576 NK cells were entirely resistant to daratumumab-induced fratricide, with no detectable specific cytotoxicity when exposed to increasing concentrations of daratumumab. Conversely, peripheral blood NK cells were sensitive to daratumumab-induced fratricide (up to 33% cytotoxicity within 3 hrs of daratumumab exposure). FT576 NK cells demonstrated enhanced cytotoxicity against the MM1.S MM cell line during a long-term cytotoxicity assay compared with control NK cells that lacked CAR expression (62% cytotoxicity for FT576 vs 26% for control). In addition, cellular persistence was greater than NK cells lacking the IL-15RF protein, and FT576 NK cells demonstrated the unique ability to expand in vitro absent of exogenous cytokine support (61-fold expansion vs. 4-fold for IL-15RF negative). Importantly, FT576 NK cells remained ADCC competent, as combination with daratumumab enhanced cytotoxicity against MM cell lines in a 2D cytotoxicity assay. Additionally, FT576 mediated direct cytotoxicity against RPMI-8226 MM spheroids, leading to >99% cytotoxicity in a 3D-spheroid culture model. Preclinical studies are ongoing to support the advancement of FT576 as the first-of-kind cellular therapeutic for the combination of anti-BCMA CAR and mAb-directed targeting of MM. Disclosures Bjordahl: Fate Therapeutics, Inc.: Employment. Gaidarova:Fate Therapeutics, Inc: Employment. Goodridge:FATE THERAPEUTICS: Employment. Mahmood:Fate Therapeutics, Inc: Employment. Bonello:Fate Therapeutics, Inc.: Employment. Robinson:Fate Therapeutics, Inc.: Employment. Ruller:Fate Therapeutics, Inc.: Employment. Pribadi:Fate Therapeutics, Inc.: Employment. Lee:Fate Therapeutics, Inc.: Employment. Abujarour:Fate Therapeutics, Inc.: Employment. Dinella:Fate Therapeutics, Inc.: Employment. Huffman:Fate Therapeutics, Inc.: Employment. Chu:FATE THERAPEUTICS: Employment. Valamehr:Fate Therapeutics, Inc: Employment.

Efficacy and Safety of Pre-approval Carfilzomib-Based Therapy of Multiple Myeloma in Daily Practice – Experience from a German Academic Center

Bortezomib (bort), the first-in-class proteasome inhibitor (PI) has become integral part of the standard-of-care treatment in multiple myeloma (MM) over the last decade. Carfilzomib (carf), the second generation PI, was granted approval by the U.S. Food and Drug Administration in 2012, however, approval by the European health authorities is still pending. Our data from one of the first “real life” experiences at a German academic center demonstrate a valid role of carf in combination treatment of advanced MM.

Predictive Factors of Survival After Thalidomide Therapy in Advanced Multiple Myeloma: Long-Term Follow-Up of a Prospective Multicenter Nonrandomized Phase II Study in 120 Patients

Thalidomide monotherapy has demonstrated consistent results in the treatment of advanced multiple myeloma. We report a 9-year follow-up of a French multicenter nonrandomized phase II study that evaluated the effect of oral thalidomide in 120 patients with advanced multiple myeloma. Independent predictors of survival were response to last therapy, performance status, serum β(2)-microglobulin level, platelet count, and response at day 60 of treatment. Thalidomide monotherapy has demonstrated consistent results in the treatment of advanced multiple myeloma. We report the 9-year follow-up of a French multicenter, nonrandomized, phase II study that evaluated the effect of oral thalidomide in advanced multiple myeloma. Thalidomide was started at 200 mg/d and increased to 400 mg/d at day 15. One hundred twenty patients were enrolled in 2 months at 33 centers. The overall response rate was 31.7% (38/120) on day 60. Overall survival rates were 47.5% (95% confidence interval [CI], 38.6-56.4), 25.0% (95% CI, 17.3-32.7), 11.7% (95% CI, 5.9-17.4), and 7.5% (95% CI, 2.8-12.2) at 1, 3, 6, and 9 years, respectively. Independent predictors of short survival at 1, 3, 6, and 9 years were multiple myeloma refractory to last therapy, performance status ≥ 2, serum β(2)-microglobulin level ≥ 3.5 mg/L, platelet count < 152 × 10(9)/L, and nonresponse at day 60 (Cox proportional hazards regression model). Our study identified 5 independent unfavorable prognostic factors associated with short survival. These prognostic factors were very robust, allowing the prediction of patient survival not only during the first year but also during 3, 6, and even 9 years after the beginning of treatment.

Unrelated Donor Hematopoietic Stem Cell Transplantation for the Treatment of Advanced Multiple Myeloma: The John Theurer Cancer Center Experience,

Abstract 4162Allogeneic hematopoietic stem cell transplantation has been associated with a graft-versus-myeloma effect and may be the only potentially curative option for patients with advanced multiple myeloma. Unfortunately, the majority of patients (pts) do not have an HLA-identical sibling. Unrelated donor transplantation is an alternative option for these patients. We conducted a retrospective analysis of patients with advanced multiple myeloma who received an unrelated donor (URD) hematopoietic stem cell transplant at our institution between 11/1997 and 11/2010. Analyses were done using Kaplan Meier survival and Cox regression on the SAS version 9.2 software.Between 11/1997 and 11/2010, 27 pts with multiple myeloma received an URD transplant. One patient was lost to follow-up and 26 pts are evaluable. Patient characteristics included: median age 52 years (range 37–64), male 58%, all patients had prior autologous transplant (23% of pts had 2 or more prior transplants), and 43% of pts had refractory or progressive disease at the time of transplantation. Transplant regimens were ablative (defined as melphalan dose > 140mg/m2) in 73% of pts. GVHD prophylaxis was tacrolimus-based in all. Hematopoietic cell source was peripheral blood for 92% of pts, 46% of pts received a 10/10 HLA matched URD and 54% had a least one allele mismatch. Results:With a median follow up of 3.4 years, 54% of patients are alive and 47% of patients are progression-free. The treatment-related mortality at day 100 was 15%. The incidence of acute graft-versus-host disease (GVHD) was 44% and chronic GVHD 25%. Univariate analysis of risk of progression or relapse and overall survival failed to show any significance for disease status at the time of transplantation, degree of donor match, transplant regimen, refractoriness to bortezomib or lenalidomide, acute or chronic GVHD. Conclusion:In this analysis, URD transplantation has an acceptable treatment related mortality, and leads to durable remissions even in patients with relapsed and/or refractory disease. The 3.4 year PFS is similar to the BMT CTN 0102 sibling data and compares favorably to related donor transplantation for relapsed disease. In comparison to the BMT CTN study, the preparative regimen in this current analysis was overall more intense and regimen intensity has been previously shown to be significant. Allogeneic transplantation is an effective treatment strategy in multiple myeloma. Unrelated donor transplantation should be offered to patients with advanced multiple myeloma who do not have an HLA-identical sibling. Disclosures:No relevant conflicts of interest to declare.

Good Safety and Tolerance Profiles of Long Term Treatment of Advanced Multiple Myeloma (MM) with Bortezomib.

Bortezomib is a first-in-class proteasome inhibitor approved for the treatment of MM patients who have received at least one prior therapy. Classically, patients receive bortezomib 1.3 or 1.0 mg/m2 by IV bolus on days 1, 4, 8, and 11 of a 21-day cycle, associated or not to dexamethasone, for a total number of 8 cycles. Such administration schema is associated with a remarkable anti-tumor activity and response. However, a significant number of patients who are initially responders to bortezomib, will progress after drug discontinuation, raising the question of long term or maintenance treatment with bortezomib. The objective of this analysis was to evaluate the tolerance and safety profiles of long term treatment with bortezomib in a cohort of 16 patients with relapsed and/or refractory MM treated in a single institution. Eligible patients for this analysis are those who had relapsed MM, and who continued to receive bortezomib (1.3 or 1.0 mg/m2) as a long term therapy beyond the classical 8 cycles. All medical charts were uniformly reviewed in detail for assessment of toxicity, safety and response. The median age was 53 (range, 27–74) years. The majority of patients had already received at least one prior autologous or allogeneic stem cell transplantation (n=12; 75%). Also, 12 patients (75%) had received prior treatment with thalidomide at a median dose of 200 mg/day, for a median duration of 7 months. Before treatment with bortezomib, 7 patients (44%) already had some form of peripheral neuropathy (PN). With a median follow-up of 16 months from bortezomib initiation, patients from this series received a median of 10 (range, 9–16) cycles of bortezomib administered over a median period of 11 (range, 7–35) months. Overall, 6 patients had evidence of bortezomib-associated PN (38%; 4 grade 1, 1 grade 2 and 1 grade 3; sensory symptoms in all cases). Other bortezomib-related toxicities included thromobopenia (n=8; 50%; 1 grade 1, 5 grade 2, and 2 grade 3–4). General fatigue was also common and was encountered in 5 (31%) patients. Overall, bortezomib-associated toxicities led to dose reduction or increase of treatment cycle duration in 9 patients (56%), but none of the patients had to definitively discontinue treatment because of unacceptable toxicity. At last follow-up, 6 patients are still receiving bortezomib, 4 patients died from disease progression, no patient died from treatment-related causes, and the remaining 12 patients are still alive. Long term treatment with bortezomib was associated with an objective disease response rate in 87% (95%CI, 60–98%) of patients (n=14; 3 CR, 8 VGPR, 3 PR). The Kaplan-Meier estimate for overall survival is shown in the figure below. Though relatively small, results from this series suggest that long term treatment with bortezomib is feasible. Toxicity, tolerance and safety profiles of long term treatment are comparable to those observed with the standard schedule and manageable after dose reduction. Therefore, prospective studies aiming to optimize bortezomib administration schedule and duration (beyond the classical 8 cycles) are warranted, since such long term treatment can yield major objective disease response. [Display omitted]

Efficacy and safety of bortezomib in patients with plasma cell leukemia

The prognosis of patients with plasma cell leukemia (PCL), an aggressive variant of multiple myeloma (MM), is usually poor. Bortezomib is the first proteasome inhibitor approved for the treatment of advanced MM. Currently available information regarding the role of bortezomib in PCL is scanty and derives from anecdotal, single-case reports. The authors conducted a retrospective survey of unselected Italian patients with primary or secondary PCL who were treated with bortezomib outside of clinical trials. Twelve evaluable patients were recorded who had received bortezomib for 1 to 6 cycles as either a single agent or variously combined with other drugs. Three patients were treated with bortezomib as frontline therapy, and 9 patients received bortezomib after 1 to 4 lines of chemotherapy, including autologous stem cell transplantation and thalidomide. According to the International uniform response criteria of the International Myeloma Working Group, 5 partial responses (defined as a reduction in M-protein of >50%), 4 very good partial responses (defined as a reduction of >90% in M-protein), and 2 complete responses (defined as negative immunofixation) were achieved, for a response rate of 92%. Responses did not appear to be influenced by previous treatments or by other clinical or biologic parameters, including chromosome 13 deletion or the combination of bortezomib with other drugs. The median progression-free and overall survivals after bortezomib were 8 months and 12 months, respectively. At the time of last follow-up, 8 patients were alive 6 to 21 months after treatment with bortezomib, 4 of whom were in very good partial or complete responses. Grade 3/4 hematologic or neurologic toxicities (graded according to the Common Terminology Criteria for Adverse Events [CTCAE; version 3]) were reported to occur in 9 patients and 1 patient, respectively, whereas 6 patients experienced possible or documented infections. Bortezomib appears to be an effective drug for PCL that could significantly improve the usually adverse clinical outcome of these patients.

Features and Risk Factors of Peripheral Neuropathy during Treatment of Advanced Multiple Myeloma with Bortezomib.

Bortezomib has demonstrated activity and safety in heavily pretreated patients with relapsed and/or refractory multiple myeloma (MM). Peripheral neuropathy (PN) is among the most frequent adverse events reported with bortezomib, requiring dose-adjustment and careful patient-clinical monitoring. The aim of this retrospective single centre study was to determine the frequency, characteristics, and reversibility of PN from bortezomib treatment of 100 consecutive advanced MM patients treated with bortezomib 1.0 or 1.3 mg/m2 IV bolus on days 1, 4, 8, and 11, every 21 days. PN was evaluated by investigator neurological examination at baseline, during the study, and at last follow-up. Patients characteristics at baseline prior to bortezomib initiation were as follow: median age: 60 (range, 27–77), prior history of diabetes: n=8 (8%), prior autologous transplantation: n=76 (76%), prior treatment with thalidomide: n=75 (75%) with a median dose of 200 (range, 50–600) mg for a median duration of 8 (range, 1–61) months. Median duration between thalidomide discontinuation and bortezomib initiation was 5 (range, 0–43) months. Before treatment with bortezomib, 48 patients (48%) already had some form of PN [grade 1, n=27 (56%); grade 2, n=16 (33%); grade 3, n=5 (11%)]. With a median follow-up of 8 (range, 0.1–32) months from bortezomib initiation, patients from this series received a median of 4 (range, 1–12) cycles of bortezomib. Bortezomib-related emergent PN was observed in 38 patients (38%; 95%CI, 28–47%), with grade 1, 2, 3, and 4 PN occurring in 17 (45%), 15 (39%), 5 (13%) and 1 (3%) patients respectively. Median time to onset of bortezomib-related PN was 53 (range, 11–182) days after bortezomib initiation. In most cases (n=30; 79%), patients had sensory symptoms, while 8 patients (21%) experienced both sensory and motor symptoms. Bortezomib-related PN led to dose reduction or discontinuation in 18 patients. Of the 38 patients with bortezomib-related PN, resolution to baseline or improvement occurred in 20 (53%) patients, at a median time of 3 (range, 1–8) months. In univariate analysis, comparing patients with and without bortezomib-related PN, prior history of treatment with thalidomide (P=0.009), patient baseline grade of PN at bortezomib initiation (P=0.04), number of bortezomib cycles administered (P=0.0005), and cumulative dose (mg) of bortezomib received by patients (P=0.001), were found to be significantly associated with the risk of emergence of bortezomib-related PN. In multivariate analysis, the total number of cycles of bortezomib (less or more than 4 cycles), and a prior history of treatment with thalidomide were the strongest parameters significantly associated with an increased incidence of bortezomib-related PN (P=0.03; OR=2.6; 95%CI, 1.1–6.1 and P=0.02; OR=3.9; 95%CI, 1.2–12.6 respectively). In all, we conclude that, though relatively frequent, bortezomib-associated PN seemed reversible in a majority of patients and manageable after dose reduction or discontinuation. However, the finding that the development of bortezomib-related PN seems to be dependent of the patient history of prior neurotoxic therapy (mainly thalidomide), raises the question of the optimal sequence and schedule of administration of these anti-MM effective drugs as single agents, but also in combination.

Frequency, Characteristics, and Reversibility of Peripheral Neuropathy During Treatment of Advanced Multiple Myeloma With Bortezomib

To determine the frequency, characteristics, and reversibility of peripheral neuropathy from bortezomib treatment of advanced multiple myeloma. Peripheral neuropathy was assessed in two phase II studies in 256 patients with relapsed and/or refractory myeloma treated with bortezomib 1.0 or 1.3 mg/m2 intravenous bolus on days 1, 4, 8, and 11, every 21 days, for up to eight cycles. Peripheral neuropathy was evaluated at baseline, during the study, and after the study by patient-reported symptoms using the Functional Assessment of Cancer Therapy Scale/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) questionnaire and neurologic examination. During the study, peripheral neuropathy was also evaluated by investigator assessment. A subset of patients underwent nerve conduction studies (n = 13). Before treatment, 194 (81%) of 239 patients had peripheral neuropathy by FACT/GOG-Ntx questionnaire, and 203 (83%) of 244 patients had peripheral neuropathy by neurologic examination. Treatment-emergent neuropathy was reported in 35% of patients, including 37% (84 of 228 patients) receiving bortezomib 1.3 mg/m2 and 21% (six of 28 patients) receiving bortezomib 1.0 mg/m2. Grade 1 or 2, 3, and 4 neuropathy occurred in 22%, 13%, and 0.4% of patients, respectively. The incidence of grade > or = 3 neuropathy was higher among patients with baseline neuropathy by FACT/GOG-Ntx questionnaire compared with patients without baseline neuropathy (14% v 4%, respectively). In all 256 patients, neuropathy led to dose reduction in 12% and discontinuation in 5%. Of 35 patients with neuropathy > or = grade 3 and/or requiring discontinuation, resolution to baseline or improvement occurred in 71%. Bortezomib-associated peripheral neuropathy seemed reversible in the majority of patients after dose reduction or discontinuation. Although severe neuropathy was more frequent in the presence of baseline neuropathy, the overall occurrence was independent of baseline neuropathy or type of prior therapy.

Proteasome inhibitors as therapeutics

The ubiquitin-proteasome pathway is a principle intracellular mechanism for controlled protein degradation and has recently emerged as an attractive target for anticancer therapies, because of the pleiotropic cell-cycle regulators and modulators of apoptosis that are controlled by proteasome function. In this chapter, we review the current state of the field of proteasome inhibitors and their prototypic member, bortezomib, which was recently approved by the U.S. Food and Drug Administration for the treatment of advanced multiple myeloma. Particular emphasis is placed on the pre-clinical research data that became the basis for eventual clinical applications of proteasome inhibitors, an overview of the clinical development of this exciting drug class in multiple myeloma, and a appraisal of possible uses in other haematological malignancies, such non-Hodgkin's lymphomas.

Proteasome inhibitors as therapeutics

The ubiquitin–proteasome pathway is a principle intracellular mechanism for controlled protein degradation and has recently emerged as an attractive target for anticancer therapies, because of the pleiotropic cell-cycle regulators and modulators of apoptosis that are controlled by proteasome function. In this chapter, we review the current state of the field of proteasome inhibitors and their prototypic member, bortezomib, which was recently approved by the U.S. Food and Drug Administration for the treatment of advanced multiple myeloma. Particular emphasis is placed on the pre-clinical research data that became the basis for eventual clinical applications of proteasome inhibitors, an overview of the clinical development of this exciting drug class in multiple myeloma, and a appraisal of possible uses in other haematological malignancies, such non-Hodgkin's lymphomas.

Proteasome inhibition as a therapeutic strategy for hematologic malignancies

The ubiquitin–proteasome pathway is a principal intracellular mechanism for controlled protein degradation and has recently emerged as an attractive target for anticancer therapies since several cell cycle regulators and modulators of apoptosis are degraded through this pathway. The current state of the field of proteasome inhibitors and their prototypic member, bortezomib, which was recently approved by the US Food and Drug Administration for the treatment of advanced multiple myeloma, is reviewed. Particular emphasis is placed on the preclinical research data that became the basis for eventual clinical applications of proteasome inhibitors, an overview of the clinical development of this exciting drug class in multiple myeloma, and an appraisal of possible uses in other hematologic malignancies, such as non-Hodgkin’s lymphomas.

Smoldering and polarized inflammation in the initiation and promotion of malignant disease

Smoldering and polarized inflammation in the initiation and promotion of malignant disease

Molecular characterization of PS-341 (bortezomib) resistance: implications for overcoming resistance using lysophosphatidic acid acyltransferase (LPAAT)-β inhibitors

PS-341 (bortezomib, Velcadetrade mark) is a promising novel agent for treatment of advanced multiple myeloma (MM); however, 65% of patients with relapsed refractory disease in a phase II study do not respond to PS-341. We have previously shown that lysophosphatidic acid acyltransferase (LPAAT)-beta inhibitor CT-32615 triggers caspase-dependent apoptosis, and can overcome resistance to conventional therapeutics (i.e., dexamethasone, doxorubicin, melphalan) in MM cells. In this study, we therefore determined whether CT-32615 could also overcome resistance to PS-341. We first characterized molecular mechanisms of resistance to PS-341 in DHL-4 cells. DHL-4 cells express low levels of caspase-3 and caspase-8; furthermore, no cleavage in caspase-8, caspase-9, caspase-3, poly ADP-ribose polymerase (PARP), or DNA fragmentation factor 45 was triggered by PS-341 treatment. We have previously shown that PS-341 treatment triggers phosphorylation of c-Jun NH(2)-terminal kinase (JNK), which subsequently induces caspase-dependent apoptosis; conversely, JNK inhibition blocks PS-341-induced apoptosis. We here show that phosphorylation of SEK-1, JNK, and c-Jun are not induced by PS-341 treatment, suggesting that PS-341 does not trigger a stress response in DHL-4 cells. Importantly, CT-32615 inhibits growth of DHL-4 cells in a time- and dose-dependent fashion: a transient G2/M cell cycle arrest induced by CT-32615 is mediated via downregulation of cdc25c and cdc2. CT-32615 triggered swelling and lysis of DHL-4 cells, without caspase/PARP cleavage or TUNEL-positivity, suggesting a necrotic response. Our studies therefore demonstrate that LPAAT-beta inhibitor CT-32615 triggers necrosis, even in PS-341-resistant DHL-4 cells, providing the framework for its evaluation to overcome clinical PS-341 resistance and improve patient outcome.

Proteasome Inhibition As a Novel Therapeutic Target in Human Cancer

The 26S proteasome is a large intracellular adenosine 5'-triphosphate-dependent protease that identifies and degrades proteins tagged for destruction by the ubiquitin system. The orderly degradation of cellular proteins is critical for normal cell cycling and function, and inhibition of the proteasome pathway results in cell-cycle arrest and apoptosis. Dysregulation of this enzymatic system may also play a role in tumor progression, drug resistance, and altered immune surveillance, making the proteasome an appropriate and novel therapeutic target in cancer. Bortezomib (formerly known as PS-341) is the first proteasome inhibitor to enter clinical practice. It is a boronic aid dipeptide that binds directly with and inhibits the enzymatic complex. Bortezomib has recently shown significant preclinical and clinical activity in several cancers, confirming the therapeutic value of proteasome inhibition in human malignancy. It was approved in 2003 for the treatment of advanced multiple myeloma (MM), with approximately one third of patients with relapsed and refractory MM showing significant clinical benefit in a large clinical trial. Its mechanism of action is partly mediated through nuclear factor-kappa B inhibition, resulting in apoptosis, decreased angiogenic cytokine expression, and inhibition of tumor cell adhesion to stroma. Additional mechanisms include c-Jun N-terminal kinase activation and effects on growth factor expression. Several clinical trials are currently ongoing in MM as well as several other malignancies. This article discusses proteasome inhibition as a novel therapeutic target in cancer and focuses on the development, mechanism of action, and current clinical experience with bortezomib.

Classical and Alternative NF-.KAPPA.B Activation Pathways and Their Roles in Lymphoid Malignancies

Nuclear factor-κB (NF-κB) is a family of highly regulated dimeric transcription factors that play pivotal roles in inflammatory responses and immunological reactions. Although they are often activated concurrently, classical and alternative NF-κB activation pathways have distinct regulatory functions, producing secondary inflammatory responses and regulating lymphoid organ development, respectively. As NF-κB functions in the proliferation, differentiation, and survival of lymphocytes, increased activation also participates in the oncogenesis of many lymphoid malignancies. Aberrant NF-κB activation in these tumor cells results from genetic changes or the activation of NF-κB pathways by indirect mechanisms. Recent observations have suggested that NF-κB provides many of the requirements for cellular transformation. Bcl-3, a member of the IκB family, is overexpressed in t (2 ; 5)+ anaplastic large cell lymphoma due to genetic and epigenetic alterations. The different contributions of the classical and alternative NF-κB pathways to tumorigenesis, however, are not well understood. The clinical importance of NF-κB is also being recognized, with the approval of the NF-κB inhibitor bortezomib for treatment of advanced multiple myeloma. A better understanding of the molecular pathways involving NF-κB will surely contribute to more sophisticatedly targeted treatments for malignancies in the future.

Molecular Characterization of PS-341 (bortezomib) Resistance: Implications for Overcoming Resistance Using Lysophosphatidic Acid Acyltransferase (LPAAT)-β Inhibitors.

PS-341 (bortezomib, Velcade™) is a promising novel agent for treatment of advanced multiple myeloma (MM); however, 65% of patients with relapsed refractory disease in a phase II study did not respond. Lysophosphatidic acid (LPA) is a phospholipid which mediates tumor cell migration and invasion. Recent studies have shown that inhibition of LPAAT-β inhibits both Ras/Raf/Erk and PI3K/Akt signaling cascades. We have previously shown that lysophosphatidic acid acyltransferase (LPAAT)-β inhibitor CT-32615 triggers caspase-dependent apoptosis, and can overcome resistance to conventional therapeutics (ie, dexamethasone, doxorubicin, melphalan) in MM cells. In this study, we determined whether CT-32615 could also overcome resistance to PS-341. We first characterized molecular mechanisms of resistance to PS-341 in DHL-4 lymphoma cells. DHL-4 cells express low levels of caspase-3 and caspase-8; furthermore, no cleavage in caspase-8, caspase-9, caspase-3, poly ADP-ribose polymerase (PARP), or DNA fragmentation factor (DFF) 45 is triggered by PS-341 treatment. We have previously shown that PS-341 treatment triggers phosphorylation of c-Jun NH2-terminal kinase (JNK), which subsequently induces caspase-dependent apoptosis; conversely, JNK inhibition blocks PS-341-induced apoptosis. Here we show that PS-341 does not induce phosphorylation of SEK-1, JNK, and c-Jun in DHL-4 cells, suggesting that it does not trigger a stress response. Importantly, CT-32615 inhibits growth of DHL-4 cells in a time- and dose-dependent fashion: a transient G2/M cell cycle arrest induced by CT-32615 is mediated via downregulation of cdc25c and cdc2. CT-32615 triggers swelling and cell membrane destruction in DHL-4 cells, without caspase/PARP cleavage or TUNEL-positivity, suggesting a necrotic response. Our studies therefore demonstrate that LPAAT-β inhibitor CT-32615 triggers necrosis even in PS-341-resistant DHL-4 cells, providing the framework for its evaluation to overcome clinical PS-341 resistance and improve patient outcome.

O95 Treatment of advanced multiple myeloma (MM) with thalidomide (THAL). Long term follow-up in a prospective study of 121 patients

O95 Treatment of advanced multiple myeloma (MM) with thalidomide (THAL). Long term follow-up in a prospective study of 121 patients

Cost-effectiveness of high-dose chemotherapy in first-line treatment of advanced multiple myeloma.

The cost-effectiveness of high-dose chemotherapy in multiple myeloma was considered as part of a UK National Health Service Executive regional evidence-based appraisal process. The use of high-dose chemotherapy supported by autologous stem cell transplantation in patients under 65 years of age was shown to provide a marginal benefit of 0.7 life-years over conventional chemotherapy. This corresponded to an incremental cost 'per life-year gained' figure of approximately pound15 000, based upon initial treatment costs and trial-period data only. The use of high-dose chemotherapy in the first-line treatment of advanced multiple myeloma improves event-free and overall survival and appears to be a cost-effective treatment option.

Chimaeric anti-interleukin 6 monoclonal antibodies in the treatment of advanced multiple myeloma: a phase I dose-escalating study.

Interleukin 6 plays a key role in the pathogenesis of multiple myeloma (MM). Therefore we conducted a phase I dose-escalating study with chimaeric monoclonal anti-IL6 antibodies (cMab) in MM patients resistant to second-line chemotherapy. The cMab (CLB IL6/8; Kd 6.25 x 10(-12)M) was given in two cycles of 14 daily infusions, starting on day 1 and day 28, repectively, with a daily dose of 5 mg in patients 1-3, 10 mg in patients 4-6, 20 mg in patients 7-9 and 40mg in patients 10-12 (total dose 140 mg, 280mg, 560 mg and 1120 mg of anti-IL6, respectively). 11/12 patients had elevated pretreatment IL6 levels. Except for transient thrombocytopenia in two patients there was no toxicity. There were no changes in haemoglobin levels, granulocyte count, liver enzymes or renal function. No human anti-chimaeric antibodies were induced. This was also reflected in a long half-life time of the cMab (median 17.8 d), resulting in accumulation of the anti-IL6 cMab and high levels of circulating IL6. However, this was in the form of biologically inactive IL6/cMab complexes and did not result in acceleration of the disease. Although C-reactive protein (CRP) levels were decreased to below detection level in 11/12 patients, indicating effective IL6 blocking, none of the patients achieved a response according to the standard criteria. We conclude that this chimaeric anti-IL6 Mab has a low toxicity, low immunogenicity and a long T1/2. A dose of 40 mg/d for 14 d can safely be used in future phase II studies.

252 Idarubicin, cyclophosphamide, vincristine and methylprednisolone followed by G-CSF in the treatment of advanced multiple myeloma

Seventeen multiple myeloma (2, S.IIA, 1, S.IIB; and 14, S.IIIA) and 1 loco-regional advanced extramedullary myeloma patients were treated with ICOMP chemotherapy (Idarubicin, I 10mg/m² day 1; Cyclophosphamide, CTX 1.2g/m² days 1 and 3; Vincristine, O 1.2mg/m² day 1 and methylprednisolone, MP 250mg days I and 3, 125mg days 2 and 4). All drugs were given IV. G-CSF (5 J.μg/kg) was administered SC from day 5 to recovery from neutropenia. All patients, but one, had received prior chemotherapy (median 3 types combmations, range 1–7). Nine had relapsing and 9 resistant disease to previous treatment. Five patients discontinued therapy, 1 after the 1^st cycle because of herpes zoster, 3 because of disease progression (l after the 2^nd, 1 after the 3^rd and 1 after the 5^th cycle). The last developed a non-therapy related myocardial infarction 5 days after the 3^rd cycle. Nine PR, 4 SD and 1 PD were observed in the 13 patients who completed at least 6 cycles. In the first 6 cycles, 18/18, 16/17, 14/16, 12/14, 12/14 and 11/13 patients respectively received between 75% and 100% of the planned I dose and 18/18, 16/17, 14/16, 14/14, 13/14 and 12/13 patients 75%–100% of the projected CTX dose. A WBC <1000/cmm was documented in 10/18 (median 3.5 days, range 2–11), 9/17 (4, 2–15), 8/16 (3, 2– 6), 7/14 (3, 1–5), 7(14 (3, 1–5) and 5/13 (3, 2–6) from the 1st to the 6th cycle and a platelet count < 100,000/cmm in 7/18 (9, 5–28), 9/17 (8, 1–31),7/16 (10, 3–28), 7/l4 (6, 2–28), 8/14 (7, 2–34), 5/13 (2, 1–20). Our results indicate that the therapeutic regimen adopted is reasonably well tolerated as well as active against advanced MM.