Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Quality of response is associated with prolonged overall survival (OS) in newly diagnosed multiple myeloma patients. This cohort study within the phase 3 Assessment of Proteasome Inhibition for Extending Remissions (APEX) trial of bortezomib versus dexamethasone in relapsed myeloma assessed the relationship between quality of response to bortezomib (n = 315) and clinical benefit. Treatment-free interval (TFI), time to alternative therapy (TTAT), time to progression (TTP) and OS were assessed in response-evaluable patients in the bortezomib arm in cohorts defined by achievement of complete response (CR; n = 27), very good partial response (VGPR; n = 31), partial response (PR; n = 77), minimal response (MR; n = 21) or non-response (NR, including stable and progressive disease; n = 159). CR was associated with significantly longer median TFI (24.1 vs. 6.9/6.4 months) and TTAT (27.1 vs. 13.6/14 months) versus VGPR/PR. Median TTP was similar in CR, VGPR and PR cohorts; median OS was not reached. Patients achieving MR appeared to have prolonged median TFI (3.8 vs. 2.3 months), TTAT (8.7 vs. 6.2 months), TTP (4.9 vs. 2.8 months) and OS (24.9 vs. 18.7 months) versus NR. In conclusion, bortezomib had substantial activity in relapsed myeloma patients; CR may be a surrogate marker for significant clinical benefit with bortezomib. MR appeared to be valid as a separate response category in this setting.
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PMID:The relationship between quality of response and clinical benefit for patients treated on the bortezomib arm of the international, randomized, phase 3 APEX trial in relapsed multiple myeloma. 1867 66

Haematological toxicities and thromboembolic (TE) events are common complications of myeloma therapy. TE risk may be elevated with combination regimens, notably thalidomide/lenalidomide plus high-dose dexamethasone; concomitant erythropoietin appears to further increase the risk with lenalidomide-dexamethasone. We characterised thrombocytopenia and neutropenia in the phase 3 APEX (Assessment of Proteasome Inhibition for Extending Remissions) study of bortezomib versus high-dose dexamethasone in relapsed myeloma, and calculated the incidences of deep-vein thrombosis (DVT)/pulmonary embolism (PE) with: bortezomib or dexamethasone +/- erythropoietin in APEX; bortezomib +/- dexamethasone +/- erythropoietin in two phase 2 studies of relapsed/refractory myeloma. Bortezomib-associated thrombocytopenia and neutropenia were transient, predictable and manageable; mean platelet and neutrophil counts followed a cyclical pattern, and improved over the treatment course. Grade 3/4 thrombocytopenia incidence was higher with bortezomib versus dexamethasone (26%/4% vs. 5%/1%), but significant bleeding events were comparable (4% vs. 5%). DVT/PE incidence was low (< or =3.1%) in all analyses; addition of dexamethasone/erythropoietin did not affect TE risk. In APEX, TE risk appeared lower with bortezomib versus dexamethasone. Bortezomib caused transient and cyclical thrombocytopenia and was not associated with elevated TE risk, alone or with dexamethasone +/- erythropoietin. Preliminary data suggest bortezomib may reduce the thrombogenic potential of combination regimens via inhibition of platelet function or other mechanism-specific effects on coagulation.
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PMID:Characterisation of haematological profiles and low risk of thromboembolic events with bortezomib in patients with relapsed multiple myeloma. 1871 53

Proteasome inhibitors (PIs), such as bortezomib, carfilzomib or NPI-0052, have excellent clinical activity in patients with multiple myeloma and mantle cell lymphoma, and they are currently being evaluated in combination with other agents in patients with solid tumors. Although they exert broad effects on cancer cells, their ability to (1) stabilize pro-apoptotic members of the BCL-2 family, (2) inhibit the two major pathways leading to NFkappaB activation, and (3) cause the build-up of misfolded proteins appear to be particularly important. In addition, PIs may disrupt tumor-stromal interactions that drive NFkappaB activation and angiogenesis and in such a way sensitize cancer cells to other agents. Still, drug resistance ultimately emerges in all tumors that initially respond to PIs. This review provides an overview of the current thinking about how PIs may kill cancer cells exemplified for pancreatic cancer and the possible mechanisms involved in resistance to PIs.
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PMID:Mechanisms of proteasome inhibitor action and resistance in cancer. 1881 17

Proteasome inhibitors and immunomodulatory drugs (IMiDs) have demonstrated clinical potential as novel therapies for non-Hodgkin lymphoma (NHL). Bortezomib, a peptide aldehyde derivative that inhibits the proteasome by binding directly to its active sites, is the most extensively studied agent in the clinical setting. Single-agent bortezomib is effective in several lymphoid malignancies, and is recommended for second-line treatment of mantle-cell lymphoma (MCL). Ongoing trials are investigating the combination of bortezomib with chemotherapy, and with agents that target Bcl-2 proteins. Although proteasome inhibitors are potentially potent anti-tumor drugs, the pleotropic nature of their biological effects means that further research is required to elucidate the optimal combinations, doses and schedules. In addition to proteasome inhibitors, the IMiDs, such as lenalidomide, have the potential to improve outcomes for patients with NHL. These drugs inhibit cell growth and proliferation by several mechanisms, including blocking the effect of growth factors and stimulating T cells and natural killer cells. Lenalidomide is particularly effective in lymphoproliferative disorders such as multiple myeloma, and is active in patients with various forms of NHL, with a favourable side-effect profile. Complimentary clinical and pharmacological features suggest that lenalidomide may be effective when combined with monoclonal antibodies. Ongoing and future studies will provide further information.
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PMID:Novel approaches for the treatment of NHL: Proteasome inhibition and immune modulation. 1882 34

The 26S proteasome regulates the degradation of many proteins involved in cell cycle control, apoptosis, and tumor growth. The inhibition of the proteasome by specific inhibitors is a viable target for anti-tumor therapy Most prominently, the proteasome inhibitor bortezomib (Velcade) was approved by the U.S. Food and Drug Administration (FDA) for the treatment of relapsed or refractory multiple myeloma in adults, and is presently considered for several other types of cancer including pediatric malignancies. The first clinical trials by the Children's Oncology Group (COG) were conducted with bortezomib for the treatment of refractory solid tumors and refractory leukemia. Proteasome inhibitors are a promising new class of therapeutics that should be further explored in combination with other chemotherapeutic agents for the treatment of pediatric cancer patients.
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PMID:Proteasome inhibitors in pediatric cancer treatment. 1885 1

Proteasome inhibition is a validated strategy for therapy of multiple myeloma, but this disease remains challenging as relapses are common, and often associated with increasing chemoresistance. Moreover, nonspecific proteasome inhibitors such as bortezomib can induce peripheral neuropathy and other toxicities that may compromise the ability to deliver therapy at full doses, thereby decreasing efficacy. One novel approach may be to target the immunoproteasome, a proteasomal variant found predominantly in cells of hematopoietic origin that differs from the constitutive proteasome found in most other cell types. Using purified preparations of constitutive and immunoproteasomes, we screened a rationally designed series of peptidyl-aldehydes and identified several with relative specificity for the immunoproteasome. The most potent immunoproteasome-specific inhibitor, IPSI-001, preferentially targeted the beta1(i) subunit of the immunoproteasome in vitro and in cellulo in a dose-dependent manner. This agent induced accumulation of ubiquitin-protein conjugates, proapoptotic proteins, and activated caspase-mediated apoptosis. IPSI-001 potently inhibited proliferation in myeloma patient samples and other hematologic malignancies. Importantly, IPSI-001 was able to overcome conventional and novel drug resistance, including resistance to bortezomib. These findings provide a rationale for the translation of IPSIs to the clinic, where they may provide antimyeloma activity with greater specificity and less toxicity than current inhibitors.
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PMID:Targeted inhibition of the immunoproteasome is a potent strategy against models of multiple myeloma that overcomes resistance to conventional drugs and nonspecific proteasome inhibitors. 1942 39

Proteasome inhibitors are emerging as a promising class of anti-cancer therapeutic agents. Bortezomib (PS341) is the first proteosome inhibitor with clinical significance. It acts by blocking vital functions of tumoral cells in myeloma, inducing apoptosis. Its toxicity is usually manageable. Gastrointestinal symptoms, peripheral neuropathy, neuropathic pain and thrombocytopenia are described as the most common side effects. We report on a case of cutaneous lesions induced by bortezomib in a patient with relapsed multiple myeloma (MM).
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PMID:Bortezomib-induced cutaneous lesions in multiple myeloma patients: a case report. 1909 52

Proteasome inhibitors (PIs) are effective against multiple myeloma (MM), but the mechanisms of action and bases of individual susceptibility remain unclear. Recent work linked PI sensitivity to protein synthesis and proteasome activity, raising the question whether different levels of proteasome expression and workload underlie PI sensitivity in MM cells (MMCs). Exploiting human MM lines characterized by differential PI sensitivity, we report that highly sensitive MMCs express lower proteasome levels and higher proteasomal workload than relatively PI-resistant MMCs, resulting in the accumulation of polyubiquitinated proteins at the expense of free ubiquitin (proteasome stress). Manipulating proteasome expression or workload alters apoptotic sensitivity to PI, demonstrating a cause-effect relationship between proteasome stress and apoptotic responses in MMCs. Intracellular immunostaining in primary, patient-derived MMCs reveals that polyubiquitinated proteins hallmark neoplastic plasma cells, in positive correlation with immunoglobulin (Ig) content, both intra- and interpatient. Moreover, overall proteasome activity of primary MMCs inversely correlates with apoptotic sensitivity to PI. Altogether, our data indicate that the balance between proteasome workload and degradative capacity represents a critical determinant of apoptotic sensitivity of MMCs to PI, potentially providing a framework for identifying indicators of responsiveness and designing novel combination therapies.
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PMID:The proteasome load versus capacity balance determines apoptotic sensitivity of multiple myeloma cells to proteasome inhibition. 1916 1

The frequency, characteristics and reversibility of bortezomib-associated peripheral neuropathy were evaluated in the phase III APEX (Assessment of Proteasome Inhibition for Extending Remissions) trial in patients with relapsed myeloma, and the impact of a dose-modification guideline on peripheral neuropathy severity and reversibility was assessed. Patients received bortezomib 1.3 mg/m(2) (days 1, 4, 8, 11, eight 21-d cycles, then days 1, 8, 15, 22, three 35-d cycles); bortezomib was held, dose-reduced or discontinued depending on peripheral neuropathy severity, according to a protocol-specified dose-modification guideline. Overall, 124/331 patients (37%) had treatment-emergent peripheral neuropathy, including 30 (9%) with grade >or=3; incidence and severity were not affected by age, number/type of prior therapies, baseline glycosylated haemoglobin level, or diabetes history. Grade >or=3 incidence appeared lower versus phase II trials (13%) that did not specifically provide dose-modification guidelines. Of patients with grade >or=2 peripheral neuropathy, 58/91 (64%) experienced improvement or resolution to baseline at a median of 110 d, including 49/72 (68%) who had dose modification versus 9/19 (47%) who did not. Efficacy did not appear adversely affected by dose modification for grade >or=2 peripheral neuropathy. Bortezomib-associated peripheral neuropathy is manageable and reversible in most patients with relapsed myeloma. Dose modification using a specific guideline improves peripheral neuropathy management without adversely affecting outcome.
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PMID:Reversibility of symptomatic peripheral neuropathy with bortezomib in the phase III APEX trial in relapsed multiple myeloma: impact of a dose-modification guideline. 1917 Jun 77

Bortezomib is the first approved member of a new class of anti-myeloma agents, the proteasome inhibitors. Further proteasome inhibitors are needed to optimise this promising treatment option. S-2209 [1-[1-{1-[(2,4-Dioxo-imidazolidin-1-ylimino)-methyl]-2-phenyl-ethylcarbamoyl}-2-(1H-indol-3-yl)-ethylcarbamoyl]-2-(1H-indol)] inhibits the chymotryptic activity of the human 20S proteasome (half maximal effective concentration, IC(50) approximately 220 nmol/l) which was determined by a proteasome inhibition assay. A nuclear factor kappaB inhibition assay revealed a half maximal effective concentration (EC(50)) of 0.9 micromol/l. The WST-1 growth assay showed inhibition of cell growth of all tested multiple myeloma (MM) cell lines with an IC(50) between 100 nmol/l and 600 nmol/l. Strong induction of apoptosis was seen in MM cells at nanomolar concentrations (IC(50) approximately 300 nm) as well as in primary myeloma cells. No induction of apoptosis was detected in peripheral blood mononuclear cells from healthy humans. Upregulation of p53, activation of JNK protein, and downregulation of Mcl-1 was revealed. Despite the administration of 15 mg S-2209/kg/d in wistar rats, no toxicity with respect to body weight, hepatic enzymes, creatinine or haemoglobin was seen. Proteasome inhibition in white blood cells isolated from the treated rats was higher in the S-2209 treated animals in comparison with the control animals treated with 0.1 mg/kg/d bortezomib. S-2209 is active in myeloma cells and shows a favourable toxicity profile in first in-vivo studies. S-2209 is a promising agent for further clinical development.
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PMID:The peptide-semicarbazone S-2209, a representative of a new class of proteasome inhibitors, induces apoptosis and cell growth arrest in multiple myeloma cells. 1917 Jun 78


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