Efstathios Kastritis

BET Bromodomain Inhibition as a Therapeutic Strategy to Target c-Myc

MYC contributes to the pathogenesis of a majority of human cancers, yet strategies to modulate the function of the c-Myc oncoprotein do not exist. Toward this objective, we have targeted MYC transcription by interfering with chromatin-dependent signal transduction to RNA polymerase, specifically by inhibiting the acetyl-lysine recognition domains (bromodomains) of putative coactivator proteins implicated in transcriptional initiation and elongation. Using a selective small-molecule bromodomain inhibitor, JQ1, we identify BET bromodomain proteins as regulatory factors for c-Myc. BET inhibition by JQ1 downregulates MYC transcription, followed by genome-wide downregulation of Myc-dependent target genes. In experimental models of multiple myeloma, a Myc-dependent hematologic malignancy, JQ1 produces a potent antiproliferative effect associated with cell-cycle arrest and cellular senescence. Efficacy of JQ1 in three murine models of multiple myeloma establishes the therapeutic rationale for BET bromodomain inhibition in this disease and other malignancies characterized by pathologic activation of c-Myc.

Osteonecrosis of the Jaw in Cancer After Treatment With Bisphosphonates: Incidence and Risk Factors

PURPOSE Osteonecrosis of the jaw (ONJ) has been associated recently with the use of pamidronate and zoledronic acid. We studied the incidence, characteristics, and risk factors for the development of ONJ among patients treated with bisphosphonates for bone metastases. PATIENTS AND METHODS ONJ was assessed prospectively since July 2003. The first bisphosphonate treatment among patients with ONJ was administered in 1997. Two hundred fifty-two patients who received bisphosphonates since January 1997 were included in this analysis. RESULTS Seventeen patients (6.7%) developed ONJ: 11 of 111 (9.9%) with multiple myeloma, two of 70 (2.9%) with breast cancer, three of 46 (6.5%) with prostate cancer, and one of 25 (4%) with other neoplasms (P = .289). The median number of treatment cycles and time of exposure to bisphosphonates were 35 infusions and 39.3 months for patients with ONJ compared with 15 infusions (P < .001) and 19 months (P = .001), respectively, for patients with no ONJ. The incidence of ONJ increased with time to exposure from 1.5% among patients treated for 4 to 12 months to 7.7% for treatment of 37 to 48 months. The cumulative hazard was significantly higher with zoledronic acid compared with pamidronate alone or pamidronate and zoledronic acid sequentially (P < .001). All but two patients with ONJ had a history of dental procedures within the last year or use of dentures. CONCLUSION The use of bisphosphonates seems to be associated with the development of ONJ. Length of exposure seems to be the most important risk factor for this complication. The type of bisphosphonate may play a role and previous dental procedures may be a precipitating factor.

International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma

This International Myeloma Working Group consensus updates the disease definition of multiple myeloma to include validated biomarkers in addition to existing requirements of attributable CRAB features (hypercalcaemia, renal failure, anaemia, and bone lesions). These changes are based on the identification of biomarkers associated with near inevitable development of CRAB features in patients who would otherwise be regarded as having smouldering multiple myeloma. A delay in application of the label of multiple myeloma and postponement of therapy could be detrimental to these patients. In addition to this change, we clarify and update the underlying laboratory and radiographic variables that fulfil the criteria for the presence of myeloma-defining CRAB features, and the histological and monoclonal protein requirements for the disease diagnosis. Finally, we provide specific metrics that new biomarkers should meet for inclusion in the disease definition. The International Myeloma Working Group recommends the implementation of these criteria in routine practice and in future clinical trials, and recommends that future studies analyse any differences in outcome that might occur as a result of the new disease definition.

New Criteria for Response to Treatment in Immunoglobulin Light Chain Amyloidosis Based on Free Light Chain Measurement and Cardiac Biomarkers: Impact on Survival Outcomes

PURPOSE To identify the criteria for hematologic and cardiac response to treatment in immunoglobulin light chain (AL) amyloidosis based on survival analysis of a large patient population. PATIENTS AND METHODS We gathered for analysis 816 patients with AL amyloidosis from seven referral centers in the European Union and the United States. A different cohort of 374 patients prospectively evaluated at the Pavia Amyloidosis Research and Treatment Center was used for validation. Data was available for all patients before and 3 and/or 6 months after initiation of first-line therapy. The prognostic relevance of different criteria for hematologic and cardiac response was assessed. RESULTS There was a strong correlation between the extent of reduction of amyloidogenic free light chains (FLCs) and improvement in survival. This allowed the identification of four levels of response: amyloid complete response (normal FLC ratio and negative serum and urine immunofixation), very good partial response (difference between involved and uninvolved FLCs [dFLC] < 40 mg/L), partial response (dFLC decrease > 50%), and no response. Cardiac involvement is the major determinant of survival, and changes in cardiac function after therapy can be reliably assessed using the cardiac biomarker N-terminal natriuretic peptide type B (NT-proBNP). Changes in FLC and NT-proBNP predicted survival as early as 3 months after treatment initiation. CONCLUSION This study identifies and validates new criteria for response to first-line treatment in AL amyloidosis, based on their association with survival in large patient populations, and offers surrogate end points for clinical trials.

International Myeloma Working Group consensus criteria for response and minimal residual disease assessment in multiple myeloma

Treatment of multiple myeloma has substantially changed over the past decade with the introduction of several classes of new effective drugs that have greatly improved the rates and depth of response. Response criteria in multiple myeloma were developed to use serum and urine assessment of monoclonal proteins and bone marrow assessment (which is relatively insensitive). Given the high rates of complete response seen in patients with multiple myeloma with new treatment approaches, new response categories need to be defined that can identify responses that are deeper than those conventionally defined as complete response. Recent attempts have focused on the identification of residual tumour cells in the bone marrow using flow cytometry or gene sequencing. Furthermore, sensitive imaging techniques can be used to detect the presence of residual disease outside of the bone marrow. Combining these new methods, the International Myeloma Working Group has defined new response categories of minimal residual disease negativity, with or without imaging-based absence of extramedullary disease, to allow uniform reporting within and outside clinical trials. In this Review, we clarify several aspects of disease response assessment, along with endpoints for clinical trials, and highlight future directions for disease response assessments.

Bortezomib With or Without Dexamethasone in Primary Systemic (Light Chain) Amyloidosis

PURPOSE To assess the efficacy and tolerability of bortezomib with or without dexamethasone and to define prognostic factors for patients with primary systemic light chain (AL) amyloidosis treated with bortezomib or both. PATIENTS AND METHODS Ninety-four patients from three centers were analyzed: 19% received the combination as first-line treatment, 81% had a median of two previous therapies, and 69% had refractory disease, while most patients had symptomatic heart involvement or elevated serum N-terminal pro-brain natriuretic peptide (NT-proBNP). Results A hematologic response was achieved in 71% within a median of 52 days, including 25% complete responses (CRs). Previously untreated patients had a 47% CR rate. Age 65 years or younger (P = .043) and twice weekly administration of bortezomib (P = .041) were associated with higher response rates. A cardiac response was documented in 29% of patients, in most as sustained improvement of functional class and less often as a decrease in wall thickness. Hematologic responses were associated with a cardiac response and NT-proBNP reduction. After a median follow-up of 12 months, 29% of patients had organ progression and 27% had hematologic progression. Median survival has not been reached and the 1-year survival rate is 76%. Baseline NT-proBNP was independently associated with survival (P = .001), while in a landmark analysis, survival was associated with NT-proBNP reduction of > or = 30% (P = .006) and achievement of hematologic response (P = .001). Toxicity was manageable and mostly consisted of neuropathy, orthostasis, peripheral edema, and constipation or diarrhea. CONCLUSION Bortezomib with or without dexamethasone is active in AL amyloidosis and induces rapid responses and high rates of hematologic and organ responses. Serial measurement of cardiac biomarkers is a powerful predictor of outcome.

Update on Treatment Recommendations From the Fourth International Workshop on Waldenström's Macroglobulinemia

Waldenström macroglobulinemia (WM) is a distinct B-cell lymphoproliferative disorder characterized by lymphoplasmacytic bone marrow infiltration along with an immunoglobulin M (IgM) monoclonal gammopathy. Patients with disease-related cytopenias, bulky adenopathy or organomegaly, symptomatic hyperviscosity, severe neuropathy, amyloidosis, cryoglobulinemia, cold agglutinin disease, or evidence of disease transformation should be considered for immediate therapy. Initiation of therapy should not be based on serum IgM levels alone, and asymptomatic patients should be observed. Individual patient considerations should be considered when deciding on a first-line agent including the presence of cytopenias, need for rapid disease control, age, and candidacy for autologous transplantation. Therapeutic outcomes should be evaluated using updated criteria. As part of the Fourth International Workshop on Waldenströms Macroglobulinemia, a consensus panel updated its recommendations on both first-line and salvage therapy in view of recently published and ongoing clinical trials. The panel considered encouraging results from recent studies of first-line combinations such as rituximab with nucleoside analogs with or without alkylating agents or with cyclophosphamide-based therapies (eg, cyclophosphamide, doxorubicin, vincristine, and prednisone or cyclophosphamide and dexamethasone) or the combination of rituximab with thalidomide. Such therapeutic approaches are likely to yield responses at least as good as, if not better than, monotherapy with any of the alkylating agents, nucleoside analogs, or rituximab. In the salvage setting, reuse of a first-line regimen or use of a different regimen should be considered along with bortezomib, alemtuzumab, autologous transplantation, and, in selected circumstances, allogeneic transplantation. Finally, the panel reaffirmed its encouragement of the active enrollment of patients with WM onto innovative clinical trials whenever possible.

Pathogenesis and treatment of renal failure in multiple myeloma

Renal failure is a frequent complication in patients with multiple myeloma (MM) that causes significant morbidity. In the majority of cases, renal impairment is caused by the accumulation and precipitation of light chains, which form casts in the distal tubules, resulting in renal obstruction. In addition, myeloma light chains are also directly toxic on proximal renal tubules, further adding to renal dysfunction. Adequate hydration, correction of hypercalcemia and hyperuricemia and antimyeloma therapy should be initiated promptly. Recovery of renal function has been reported in a significant proportion of patients treated with conventional chemotherapy, especially when high-dose dexamethasone is also used. Severe renal impairment and large amount of proteinuria are associated with a lower probability of renal recovery. Novel agents, such as thalidomide, bortezomib and lenalidomide, have significant activity in pretreated and untreated MM patients. Although there is limited experience with thalidomide and lenalidomide in patients with renal failure, data suggest that bortezomib may be beneficial in this population. Clinical studies that have included newly diagnosed and refractory patients indicate that bortezomib-based regimens may result in rapid reversal of renal failure in up to 50% of patients and that full doses of bortezomib can be administered without additional toxicity.

Treatment of light chain (AL) amyloidosis with the combination of bortezomib and dexamethasone

Background and Objectives High-dose melphalan and autologous stem cell transplantation is currently the treatment of choice for selected patients with AL amyloidosis; however, new treatments are needed for patients who are ineligible for or relapse after this procedure. Bortezomib is a proteasome inhibitor with proven activity in multiple myeloma, and the addition of dexamethasone results in superior outcome. We evaluated the activity and feasibility of the combination of bortezomib and dexamethasone (BD) in patients with AL amyloidosis. Design and Methods Consecutive patients with histologically proven, symptomatic AL amyloidosis were treated with BD. Results Eighteen patients, including seven who had relapsed or progressed after previous therapies were treated with BD. Eleven (61%) patients had two or more organs involved; kidneys and heart were affected in 14 and 15 patients, respectively. The majority of patients had impaired performance status and high brain natriuretic peptide values; serum creatinine was elevated in six patients. Among evaluable patients, 94% had a hematologic response and 44% a hematologic complete response, including all five patients who had not responded to prior high dose dexamethasone-based treatment and one patient under dialysis. Five patients (28%) had a response in at least one affected organ. Hematologic responses were rapid (median 0.9 months) and median time to organ response was 4 months. Neurotoxicity, fatigue, peripheral edema, constipation and exacerbation of postural hypotension were manageable although necessitated dose adjustment or treatment discontinuation in 11 patients. Interpretation and Conclusions The combination of BD is feasible in patients with AL amyloidosis. Patients achieve a rapid hematologic response and toxicity can be managed with close follow-up and appropriate dose adjustment. This treatment may be a valid option for patients with severe heart or kidney impairment.

Improved survival of patients with multiple myeloma after the introduction of novel agents and the applicability of the International Staging System (ISS): an analysis of the Greek Myeloma Study Group (GMSG).

When the novel agents thalidomide, bortezomib and lenalidomide are administered to patients with myeloma in the context of clinical trials, they are associated with a significant improvement in response, progression-free survival and in some studies, overall survival (OS); however, their effect on the outcome of unselected myeloma patients has not been fully assessed. We compared the outcome of 1376 unselected patients with symptomatic myeloma, who started treatment before or after the introduction of thalidomide. The median OS in patients who started treatment after the introduction of novel agents increased by 12 months (48 vs 36 months, P<0.001). This improvement was more pronounced in patients ⩽70 years (from 39 to 74 months, P<0.001), but less evident in patients >70 years (from 26 to 33 months, P=0.27). In patients treated after the introduction of novel agents, the international staging system (ISS) could discriminate three groups with significantly different outcomes (5-year survival for ISS stage I, II and III was 66, 45 and 18%, respectively, P<0.001). ISS was also valid in patients who actually received upfront treatment with novel drugs (4-year survival rate was 85, 61 and 26% for ISS stage I, II and III patients, P=0.001).