Mutational Spectrum, Copy Number Changes, and Outcome: Results of a Sequencing Study of Patients With Newly Diagnosed Myeloma

PURPOSE

At the molecular level, myeloma is characterized by copy number abnormalities and recurrent translocations into the immunoglobulin heavy chain locus. Novel methods, such as massively parallel sequencing, have begun to describe the pattern of tumor-acquired mutations, but their clinical relevance has yet to be established.

METHODS

We performed whole-exome sequencing for 463 patients who presented with myeloma and were enrolled onto the National Cancer Research Institute Myeloma XI trial, for whom complete molecular cytogenetic and clinical outcome data were available.

RESULTS

We identified 15 significantly mutated genes: IRF4, KRAS, NRAS, MAX, HIST1H1E, RB1, EGR1, TP53, TRAF3, FAM46C, DIS3, BRAF, LTB, CYLD, and FGFR3. The mutational spectrum is dominated by mutations in the RAS (43%) and nuclear factor-κB (17%) pathways, but although they are prognostically neutral, they could be targeted therapeutically. Mutations in CCND1 and DNA repair pathway alterations (TP53, ATM, ATR, and ZNFHX4 mutations) are associated with a negative impact on survival. In contrast, those in IRF4 and EGR1 are associated with a favorable overall survival. We combined these novel mutation risk factors with the recurrent molecular adverse features and international staging system to generate an international staging system mutation score that can identify a high-risk population of patients who experience relapse and die prematurely.

CONCLUSION

We have refined our understanding of genetic events in myeloma and identified clinically relevant mutations that may be used to better stratify patients at presentation.

A prospective comparison of 18F-fluorodeoxyglucose positron emission tomography-computed tomography, magnetic resonance imaging and whole-body planar radiographs in the assessment of bone disease in newly diagnosed multiple myeloma

BACKGROUND AND OBJECTIVES

Bone lesions in multiple myeloma (MM) have been traditionally detected by whole body X-ray (WBXR) survey although magnetic resonance imaging (MRI) has become the gold standard for detecting MM involvement of the spine and pelvis. The aim of this study was to compare a new technique, positron emission tomography (PET) with 18F fluorodeoxyglucose (FDG) integrated with computed tomography (18F-FDG PET-CT), with MRI and WBXR for baseline assessment of bone disease in MM.

DESIGN AND METHODS

We prospectively compared 18F-FDG PET-CT, MRI of the spine-pelvis and WBXR in a series of 46 patients with newly diagnosed MM. In 23 patients who received up front autologous transplantation, we also compared post-treatment PET-CT scans with MR images of the spine and pelvis.

RESULTS

Overall, PET-CT was superior to planar radiographs in 46% of patients, including 19% with negative WBXR. In 30% of patients, PET-CT scans of the spine and pelvis failed to show abnormal findings in areas in which MRI revealed an abnormal pattern of bone marrow involvement, more frequently of diffuse type. In contrast, in 35% of patients PET-CT enabled the detection of myelomatous lesions in areas which were out of the field of view of MRI. By combining MRI of the spine- pelvis and 18F-FDG PET-CT, the ability to detect sites of active MM, both medullary and extramedullary, was as high as 92%. Following transplantation, 15 patients had negative PET-CT scans (including 13 with a very good partial response or at least a near complete response), but only 8 had normal MRI.

INTERPRETATION AND CONCLUSIONS

MRI of the spine and pelvis still remains the gold standard imaging technique for the detection of bone marrow involvement in MM. 18F-FDG PET-CT provides additional and valuable information for the assessment of myeloma bone disease in areas not covered by MRI.

Translocations at 8q24 juxtapose MYC with genes that harbor superenhancers resulting in overexpression and poor prognosis in myeloma patients

Secondary MYC translocations in myeloma have been shown to be important in the pathogenesis and progression of disease. Here, we have used a DNA capture and massively parallel sequencing approach to identify the partner chromosomes in 104 presentation myeloma samples. 8q24 breakpoints were identified in 21 (20%) samples with partner loci including IGH, IGK and IGL, which juxtapose the immunoglobulin (Ig) enhancers next to MYC in 8/23 samples. The remaining samples had partner loci including XBP1, FAM46C, CCND1 and KRAS, which are important in B-cell maturation or myeloma pathogenesis. Analysis of the region surrounding the breakpoints indicated the presence of superenhancers on the partner chromosomes and gene expression analysis showed increased expression of MYC in these samples. Patients with MYC translocations had a decreased progression-free and overall survival. We postulate that translocation breakpoints near MYC result in colocalization of the gene with superenhancers from loci, which are important in the development of the cell type in which they occur. In the case of myeloma these are the Ig loci and those important for plasma cell development and myeloma pathogenesis, resulting in increased expression of MYC and an aggressive disease phenotype.

Multiple myeloma, venous thromboembolism, and treatment-related risk of thrombosis

Venous thromboembolism (VTE) is a disease with a high prevalence in elderly people, affecting > 5% of the population > 65 years of age. Cancer patients have a 4.3-fold higher incidence of thrombotic complications, due to multiple risk factors that are not always related to the disease. Among hematologic malignancies, multiple myeloma (MM) confers a high risk of developing such complications, with a VTE rate of nearly 10%. Multiple factors are involved in MM-related VTE, such as increased blood viscosity, high levels of immunoglobulin, procoagulant activity of monoclonal protein, and inflammatory cytokines. Since the introduction of the immunomodulatory derivatives (IMiDs) thalidomide and lenalidomide in the therapeutic armamentarium of MM, VTE has emerged as one of the leading complications, in particular in patients with newly diagnosed MM. In this setting, IMiDs-based treatments are associated with rates of VTE reaching values up to 14 to 26%, particularly when dexamethasone or chemotherapy are added. The optimal prophylaxis for patients receiving these antiangiogenetic agents is still a matter of debate. Due to the lack of prospective randomized clinical trials, different studies have used various anticoagulant prophylaxes, including fixed low-dose warfarin (1 mg or 1.25 mg), therapeutic doses of warfarin (international normalized ratio between 2.0 and 3.0), low molecular weight heparin, or low-dose aspirin. As yet, no study has clearly demonstrated a significant superiority of one prophylactic regimen in comparison with the others. Further investigation and more randomized clinical trials are needed to define the best thromboprophylaxis.

Therapeutic targeting of hypoxia and hypoxia-inducible factor 1 alpha in multiple myeloma

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by accumulation of malignant plasma cells (PCs) within the bone marrow (BM). The PCs are in close contact with stromal cells, which secrete growth factors and cytokines, promoting tumor cell growth and survival. Despite the availability of new drugs with immunomodulatory properties targeting the neoplastic clone and its microenvironment, MM is still an incurable disease, with patients experiencing subsequent phases of remission and relapse, eventually leading to disease resistance and patient death. It is now well established that the MM BM microenvironment is hypoxic, a condition required for the activation of the hypoxia-inducible factor 1 alpha (HIF-1α). It has been shown that HIF-1α is constitutively expressed in MM even in normoxic conditions, suggesting that HIF-1α suppression might be part of a therapeutic strategy. Constitutively activated HIF-1α enhances neovascularization, increases glucose metabolism, and induces the expression of antiapoptotic proteins. HIF-1α is thought to be one of the most important molecular targets in the treatment of cancer, and a variety of chemical inhibitors for HIF-1α have been developed to date. This review examines the role of HIF-1α in MM and recent developments in harnessing the therapeutic potential of HIF-1α inhibition in MM.

Short-term thalidomide incorporated into double autologous stem-cell transplantation improves outcomes in comparison with double autotransplantation for multiple myeloma

PURPOSE

To assess potential benefits with thalidomide incorporated into double autologous stem-cell transplantation (ASCT) for younger patients with newly diagnosed multiple myeloma (MM).

PATIENTS AND METHODS

One hundred thirty-five patients who received thalidomide from induction until the second ASCT were retrospectively analyzed in comparison with an equal number of pair mates treated with double ASCT not including thalidomide.

RESULTS

On an intention-to-treat basis, the addition of thalidomide to double ASCT effected a significant improvement in the rate (68% v 49%; P = .001) and duration (62% v 33% at 4 years; P < .001) of at least very good partial response (VGPR), time to progression (TTP; 61% v 41% at 4 years; P < .001) and progression-free survival (PFS; 51% v 31% at 4 years; P = .001). A trend was also noted for extended overall survival (OS) among thalidomide-treated patients (69% at 5 years v 53% for the control group), although the difference between the two groups was not statistically significant (P = .07). Benefits with thalidomide in increasing the rate of VGPR or better response, TTP, and PFS were confirmed in a multivariate analysis. Median OS after relapse was 24 months for patients receiving thalidomide added to double ASCT and 25 months for the control group. Overall, 17% of patients discontinued thalidomide, including 8% because of drug-related adverse events.

CONCLUSION

In comparison with double ASCT, the addition of first-line thalidomide to double ASCT improved clinical outcomes. Short-term thalidomide was generally well tolerated and had no adverse impact on postrelapse survival.

Bortezomib-based therapy combined with high cut-off hemodialysis is highly effective in newly diagnosed multiple myeloma patients with severe renal impairment

Multiple myeloma (MM) is often associated with renal insufficiency (RI) which adversely influences the prognosis. Several studies demonstrated that bortezomib can improve both renal function and outcome. We prospectively evaluated 21 newly diagnosed MM patients with severe renal impairment secondary to tubular-interstitial damage, most of them due to myeloma kidney, who were primarily treated with bortezomib-based therapy combined with high cut-off hemodialysis (HCOD). The median serum creatinine level at baseline was 6.44 mg dL(-1) and calculated median estimated glomerular filtration rate (eGFR), according to Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation, was 8 mL/min/1.73 m(2) . Serum free light chain (sFLC) median concentration was 6,040 mg L(-1) . Post induction and best stringent complete response rates were 19 and 38%, respectively. Responses were fast, occurring within a median of 1.4 months. The combination of bortezomib and HCOD led to a prompt and remarkable (>90%) decrease in sFLC levels. Sixteen patients (76%) became dialysis independent within a median of 32 days. With a median follow up of 17.2 months, the 3-year PFS and OS were 76 and 67%, respectively. No early deaths were observed. This study demonstrates that incorporation of bortezomib into induction therapy combined with HCOD is a highly effective strategy in rescuing renal function and improving outcomes in patients with MM and RI.

Thalidomide-dexamethasone as induction therapy before autologous stem cell transplantation in patients with newly diagnosed multiple myeloma and renal insufficiency

The aim of this study was to evaluate the efficacy and the toxicity of thalidomide-dexamethasone (Thal-Dex) as induction therapy before autologous peripheral blood stem cell (PBSC) transplantation in patients with newly diagnosed multiple myeloma (MM) with renal insufficiency. The study included 31 patients with a baseline creatinine clearance value <or=50 mL/min, 7 of whom required chronic hemodialysis. Patients received 4 months of Thal-Dex, followed by PBSC collection and subsequent transplantation. After induction, a partial response (PR) or greater was obtained in 23 patients (74%), including 8 (26%) who achieved a very good PR. Renal function improved more frequently in patients achieving a PR or greater (82%, vs 37% in patients achieving less than a PR; P = .04). Twenty-six patients underwent PBSC mobilization; in 17 of these patients (65%), >4 x 10(6) CD34(+) cells/kg were collected. Double autologous transplantation was performed in 15 patients, and a single autologous transplantation was performed in 7 patients. After a median of 32 months of follow-up, median event-free survival was 30 months, and median survival was not determined. According to our data, Thal-Dex is effective and safe in patients with newly diagnosed MM and renal insufficiency. Given the relationship between recovery of renal function and response to induction treatment, more intensive Thal + bortezomib regimens could be explored to rescue higher numbers of patients.

The genetic and genomic background of multiple myeloma patients achieving complete response after induction therapy with bortezomib, thalidomide and dexamethasone (VTD)

The prime focus of the current therapeutic strategy for Multiple Myeloma (MM) is to obtain an early and deep tumour burden reduction, up to the level of complete response (CR). To date, no description of the characteristics of the plasma cells (PC) prone to achieve CR has been reported. This study aimed at the molecular characterization of PC obtained at baseline from MM patients in CR after bortezomib-thalidomide-dexamethasone (VTD) first line therapy.

One hundred and eighteen MM primary tumours obtained from homogeneously treated patients were profiled both for gene expression and for single nucleotide polymorphism genotype. Genomic results were used to obtain a predictor of sensitivity to VTD induction therapy, as well as to describe both the transcription and the genomic profile of PC derived from MM with subsequent optimal response to primary induction therapy.

By analysing the gene profiles of CR patients, we identified a 5-gene signature predicting CR with an overall median accuracy of 75% (range: 72%–85%). In addition, we highlighted the differential expression of a series of genes, whose deregulation might explain patients' sensitivity to VTD therapy. We also showed that a small copy number loss, covering 606Kb on chromosome 1p22.1 was the most significantly associated with CR patients.

HIF-1α inhibition blocks the cross talk between multiple myeloma plasma cells and tumor microenvironment

Multiple myeloma (MM) is a malignant disorder of post-germinal center B cells, characterized by the clonal proliferation of malignant plasma cells (PCs) within the bone marrow (BM). The reciprocal and complex interactions that take place between the different compartments of BM and the MM cells result in tumor growth, angiogenesis, bone disease, and drug resistance. Given the importance of the BM microenvironment in MM pathogenesis, we investigated the possible involvement of Hypoxia-Inducible transcription Factor-1 alpha (HIF-1α) in the PCs-bone marrow stromal cells interplay. To test this hypothesis, we used EZN-2968, a 3rd generation antisense oligonucleotide against HIF-1α, to inhibit HIF-1α functions. Herein, we provide evidence that the interaction between MM cells and BM stromal cells is drastically reduced upon HIF-1α down-modulation. Notably, we showed that upon exposure to HIF-1α inhibitor, neither the incubation with IL-6 nor the co-culture with BM stromal cells were able to revert the anti-proliferative effect induced by EZN-2968. Moreover, we observed a down-modulation of cytokine-induced signaling cascades and a reduction of MM cells adhesion capability to the extracellular matrix proteins in EZN-2968-treated samples. Taken together, these results strongly support the concept that HIF-1α plays a critical role in the interactions between bone BM cells and PCs in Multiple Myeloma.

Biologically defined risk groups can be used to define the impact of thalidomide maintenance therapy in newly diagnosed multiple myeloma

Maintenance therapy is an attractive strategy for patients with multiple myeloma. However, the impact of maintenance thalidomide according to the underlying biology of the disease is still a matter of debate, with some studies suggesting that thalidomide is more beneficial in high risk disease, whilst others show the opposite. Biological risk groups defined by interphase fluorescence in situ hybridization (FISH) are powerful predictors of outcome. In this report we investigated the effect of maintenance thalidomide in different biological risk groups defined by different FISH categories. Our data show that maintenance thalidomide improves outcome in patients with biologically low risk disease, defined by the absence of adverse cytogenetic lesion or by the presence of hyperdiploidy alone. Conversely, thalidomide maintenance is detrimental for the overall survival of patients with biological high risk. We conclude that it is important to identify biologically low risk patients who will benefit from a maintenance strategy with thalidomide.

Suppression of MYC by PI3K/AKT/mTOR pathway inhibition in combination with all-trans retinoic acid treatment for therapeutic gain in acute myeloid leukaemia

Aberrant activity of the phosphatidylinositol-3 kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR [PAM]) pathway, as well as suppressed retinoic acid signalling, contribute to enhanced proliferation and the differentiation blockade of immature myeloid cells in acute myeloid leukaemia (AML). Inhibition of the PAM pathway was shown to affect especially mixed-lineage leukaemia-rearranged AML. Here, we sought to test a combined strategy using small molecule inhibitors against members of the PAM signalling pathway in conjunction with all-trans retinoic acid (ATRA) to target a larger group of different AML subtypes. We find that ATRA treatment in combination with inhibition of PI3K (ZSTK474), mTOR (WYE132) or PI3K/mTOR (BEZ235, dactolisib) drastically reduces protein levels of the proto-oncogene MYC. In combination with BEZ235, ATRA treatment led to almost complete eradication of cellular MYC, G1 arrest, loss of clonal capacity and terminal granulocytic differentiation. We demonstrate that PAM inhibitor/ATRA treatment targets MYC via independent mechanisms. While inhibition of the PAM pathway causes MYC phosphorylation at threonine 58 via glycogen synthase kinase 3 beta and subsequent degradation, ATRA reduces its expression. Here, we present an approach using a combination of known drugs to synergistically reduce aberrant MYC levels, thereby effectively blocking proliferation and enabling differentiation in various AML subtypes.

Biology and treatment of myeloma

In recent years significant progress has been made in the understanding of multiple myeloma (MM) biology and its treatment. Current strategies for the treatment of MM involve the concept of sequential blocks of therapy given as an induction followed by consolidation and maintenance. In an age characterized by emerging and more powerful laboratory techniques, it is of primary importance to understand the biology of MM and how this biology can guide the development of new treatment strategies. This review focuses on the genetic basis of myeloma, including the most common genetic abnormalities and pathways affected and the effects that these have on MM treatment strategies. MM biology is discussed also in the light of more recent theory of intraclonal heterogeneity.

Frailty impairs the feasibility of induction therapy but not of maintenance therapy in elderly myeloma patients: final results of the German Maintenance Study (GERMAIN)

PURPOSE

The German Maintenance Study (GERMAIN) was designed to evaluate the impact of lenalidomide maintenance after induction therapy with bortezomib, melphalan and prednisolone (VMP) in transplant-ineligible newly diagnosed multiple myeloma (MM) patients.

METHODS

Due to poor accrual and high dropout rate, only 85 patients (planned 286) entered the trial and 40 (planned 200) were randomized to lenalidomide maintenance (n = 19) vs. observation (n = 21).

RESULTS

The primary endpoint, improved progression-free survival, was not met (p = 0.3572). After a median follow-up of 12.9 months, median progression-free survival in the lenalidomide arm was 14.4 months and 11.4 months with placebo. The hazard ratio 0.621 (95% confidence interval: [0.224, 1.725]) was about the same as expected (0.625). However, with only 40 patients randomized, the actual power to detect a difference was 11%. Of patients receiving at least one dose of induction, 54% were frail according to a modified International Myeloma Working Group frailty score. Discontinuations were high during induction (47%), and affected mainly frail patients (54%). Despite a higher rate of adverse events in the lenalidomide arm (p = 0.0061), only 2 patients discontinued lenalidomide due to toxicity.

CONCLUSION

A frailty assessment with appropriate dose modification for induction therapy should be mandatory for all elderly non-transplant-eligible myeloma patients.

Prognostic impact of serial measurements of serum-free light chain assay throughout the course of newly diagnosed multiple myeloma treated with bortezomib-based regimens

We retrospectively investigated the role of serial serum-free light chain (sFLC) evaluations in 150 multiple myeloma (MM) patients treated with first-line bortezomib-based regimens. Baseline sFLC ratio (sFLCR) identified three groups of patients - normal, lightly abnormal (<100), and highly abnormal (≥100) - with different progression-free survival (PFS: 3-year estimate 72% versus 61% versus 44%, respectively, p = 0.03). Moreover, the achievement of a normal sFLCR correlated with extended PFS (49 versus 17 months, p < 0.0001) and overall survival (75 versus 43 months, p < 0.0001) as compared with abnormal sFLCR, a gain maintained in a multivariate analysis for PFS. At relapse, a high sFLCR was associated with earlier start of salvage therapy compared with sFLCR <100 (3-month probability: 89% versus 64%, p = 0.0426). In 20% of patients, sFLC escape preceded the conventional relapse by a median of 3.8 months. Our results highlight the role of sFLC assay in the prognosis and follow-up of MM.

Long-term results of thalidomide and dexamethasone (thal-dex) as therapy of first relapse in multiple myeloma

Thal-dex (TD) is an effective therapy for advanced MM. We evaluated TD as salvage treatment of MM patients at first relapse. Thal was given at a daily dose of 100 or 200 mg until progression. Dex was administered 160 mg/month. One hundred patients were enrolled. First line therapy included ASCT (72%) and conventional CHT (28%). Fifty-nine percent received a fixed thal dose of 100 mg/day. The most frequent adverse events were constipation (42%), peripheral neuropathy (58%, 5% grade 3), bradycardia (20%), skin rash (11%), and VTE (7%). Discontinuation of thal due to adverse events was recorded in eight patients. On ITT, 46% of patients achieved at least a PR. Median DOR was 28 months, median time to next therapy was 15.5 months. Median OS, TTP, and PFS were 43, 22, and 21 months, respectively. TTP and PFS were significantly longer for patients with at least PR to TD. TD was an effective salvage treatment for MM patients at first relapse, as demonstrated by durable disease control and prolonged OS. TD was well tolerated, as reflected by the long stay on treatment without disease progression (median 25 months) and a low discontinuation rate due to toxicity (8%).

The utility of newer imaging techniques as predictors of clinical outcomes in multiple myeloma

The 14th International Myeloma Workshop Kyoto, Japan, 3-7 April 2013 The International Myeloma Workshop (IMW) is a biannual meeting that gathers experts in multiple myeloma (MM) from all over the world and scientists interested in clinical and biological aspects of myeloma. The 2013 IMW was held in Kyoto, Japan and presented an interesting program with an appealing section on newer imaging techniques as predictor of outcome in asymptomatic and symptomatic MM. During the meeting, the importance of newer functional imaging techniques as new ways of assessing bone disease and the extent of marrow infiltration by myeloma cells was highlighted. This short meeting report will provide a review of new and/or functional imaging techniques, such as magnetic resonance imaging (MRI), both axial and whole body (WB-MRI), dynamic contrast enhanced (DCE) MRI, diffusion weighted imaging (DWI) and PET integrated with computed tomography.