Kumar, Shaji

Abstract Background: Therapy with proteasome inhibitors (PIs) is an effective strategy against multiple myeloma (MM), but a significant proportion of patients is primarily resistant or eventually becomes refractory. Paradoxical activation of phospho-Akt, induction of HSP27 and excessive proteasome activity in relation to polyubiquitinated protein burden are all mechanisms for bortezomib resistance in MM cells in vitro. Preclinical data showed investigational drug MLN9708, a specific, reversible, orally bioavailable, small molecule PI, to be active in MM cell lines, patient cells and mouse models and is currently under clinical investigation. We compared the signaling pathways induced by MLN2238, the biologically active form of MLN9708, and bortezomib to outline differences that could be employed to design rational combinations to overcome resistance. Results: We performed time course experiments in MM.1S cells with EC50 doses of MLN2238 and bortezomib and analyzed signaling pathways via western blotting. Compared to bortezomib, MLN2238 induced earlier cleavage of caspase 8, 9, 3 and PARP and a significant downregulation of XIAP starting at 12 hours. Early and persistent phosphorylation of Bad, known to protect from mitochondrial apoptosis, was observed in bortezomib-, but not MLN2238-treated cells, in which phospho-Bad was reduced at 24 hours. Similarly, MLN2238 decreased phosphorylated Akt and mTOR at 24 hours, while bortezomib-treated cells only showed subtle changes. Interestingly, both drugs caused downregulation of the mTOR downstream targets phospho-p70 S6 kinase and phospho-4E-BP1, albeit of different intensity. Induction of heat shock proteins was comparable with both PI, opening the possibilities for combination therapy of MLN2238 with HSP90 inhibitors. Importantly, the inhibitory effect on phosphorylation of Akt, mTOR and Bad persisted when MM.1S cells were treated with MLN2238 in the presence of bone marrow stromal cells (BMSC). Conclusion: We observed differences in several crucial signaling pathways upon treatment of MM.1S cells with bortezomib or MLN2238. In particular, treatment with the latter inhibited phosphorylation of Bad, Akt and mTOR, suggesting a broader pro-apoptotic and anti-proliferative profile, compared to bortezomib. MLN2238 retained the capability of targeting these substrates also in the presence of BMSC. Confirmatory data on patient-derived cells are under current investigation in our lab. We believe that these data help understanding the differences in PI pharmacodynamics and bortezomib escape. This will allow us to design new drug combinations in the future that overcome clinical resistance to PIs and improve MM patient survival. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5669. doi:1538-7445.AM2012-5669

Abstract Purpose: Surrogate biomarkers are lacking for predicting or monitoring response to anti-angiogenesis therapies. We investigated whether circulating biomarkers (CBMs) of angiogenesis (i.e., bFGF, SDF-1α, HGF, sKIT, Ang-2, and PlGF) correlated with treatment efficacy in a pooled analysis of metastatic colorectal cancer (mCRC) and recurrent glioblastoma multiforme (rGBM) patients (pts) treated with bevacizumab/sorafenib (BEV/SOR). Experimental procedures: Peripheral blood samples were obtained for CBM analyses from pts enrolled in the North Central Cancer Treatment Group (NCCTG) phase II studies N054C (mCRC, n=75, Grothey, ASCO 2010) and N0776 (rGBM, n=54, Galanis, ASCO 2010). Blood collection time points were: baseline (BL), cycle 1 day 3 (C1D3), prior to treatment cycles 2, 3, 5, 7, 9, 11, 13, and after the pt went off study. Plasma CBM levels were determined by commercially-available ELISAs (R&D Systems) and performed according to manufacturer's instructions. For each CBM, a linear regression model that adjusted for study was used to evaluate the correlation with either progression-free survival (PFS) success/failure or progression within 14 days of the last blood draw for the following measures: absolute BL levels, log2 BL levels; C1D3 log2-fold change (FC) from BL, prior to cycle 2 log2-FC from BL, last draw log2-FC from BL, and last draw log2-FC from prior draw. Results summary: There appears to be no significant difference in the PFS or overall survival (OS) between the pts on these two studies; therefore, we pooled the patients from both studies for a combined analyses. We found no difference in absolute or log2 levels for any of the CBMs during the course of BEV/SOR treatment. In these pooled analyses, we found increased absolute and increased log2 BL SDF-1α levels were significantly correlated with PFS success (p=0.023 and p=0.02, respectively). After correcting for multiple comparisons (method of Benjamini & Hochberg) the p-values <0.05 had a false-discovery-rate of 41.4%. None of the other CBM measures were significantly correlated with either PFS success/failure or progression within 14 days of the last blood draw (all p>0.10). Conclusions: This study provides preliminary evidence that SDF-1α may be a useful CBM for determining treatment efficacy in these pts treated with BEV/SOR. Further prospective validation of SDF-1α for predicting pt progression with this treatment combination in advanced disease (e.g., mCRC and rGBM) appears warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5562. doi:1538-7445.AM2012-5562

Abstract Monoclonal gammopathy of undetermined significance (MGUS) is a precursor to multiple myeloma and related diseases. The majority of MGUS cases are characterized by the expression of immunoglobulin heavy chain (IgH); however, approximately one-fifth of MGUS cases do not present with IgH expression. These individuals have light chain MGUS (LC-MGUS), a precursor to light-chain MM (LC-MM). LC-MGUS is characterized by an absence of IgH and an abnormal free light chain ratio (FLC-R), indicating excessive expression of either κ or ≤ free light chains. LC-MGUS has a prevalence of 0.8% in the general population over the age of 50, as compared with a prevalence of 3.2% for heavy-chain MGUS (HC-MGUS) (Dispenzieri, 2010). There is currently little understanding of the association between family history of HC-MGUS or multiple myeloma (MM) and LC-MGUS. We investigated whether the prevalence of LC-MGUS is elevated in first-degree relatives of patients with either HC-MGUS or MM. HC-MGUS probands expressed IgH and were recruited through a population-based study of Olmsted County residents; MM probands consisted of both HC-MM and LC-MM and were recruited through the Mayo Clinic Hematology practice. Serum samples were collected from first-degree relatives of probands older than 40 years of age and subjected to electrophoresis, immunofixation, and free light chain assay. Prevalence of LC-MGUS was calculated in all first-degree relatives combined, and in relatives from both HC-MGUS and MM families separately. We compared the prevalence in family members to that in a well-defined Olmsted County, MN cohort (Dispenzieri, 2010) of patients aged 50 and over. A total 911 relatives of 232 MM and 97 MGUS patients were studied. LC-MGUS was detected in 17/911 (1.9%) relatives, for an age- and sex-adjusted prevalence of 1.7% (95% CI, 0.9% to 2.6%). Prevalence among relatives of MM probands (age- and sex- adjusted rate 2.1%; 95% CI, 1.0% to 3.2%) was higher than among relatives of MGUS probands (age- and sex- adjusted rate 0.6%; 95% CI, 0.0%-1.6%). There was an increased risk of LC-MGUS in relatives compared to the reference population which was predominantly due to the increased risk among relatives of MM probands (risk ratio=3.4, 95% CI 2.0, 5.51) as opposed to relatives of MGUS probands (risk ratio=1.1, 95% CI, 0.3 to 4.5). Among MM probands, there was no significant difference between the prevalence increase in relatives of the 32 probands with LC-MM and that of the relatives of the 200 probands with HC-MM (3.8 vs 3.3, ratio=1.2, 95% CI: 0.3-5.1, p=0.85). We conclude that the prevalence of LC-MGUS is significantly higher among first degree family members of all MM probands compared to the general population. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5485. doi:1538-7445.AM2012-5485

Abstract Background: Activation of oncology trials is a lengthy and complex process. Recent literature has identified numerous opportunities to improve activation timelines1, 2. The Multiple Myeloma Research Consortium (MMRC) has implemented several processes to identify and overcome myeloma clinical trial activation barriers within the consortium network of 14 North American cancer centers. We examined the impact of these processes preand post- implementation and also compared activation times with published clinical trial metrics data. Methods/Results: 12 MMRC-facilitated trials had sufficient trial data available for review within the study period of May 2006 to March 2009. Activation time was defined as the time from a center's receipt of the final clinical trial protocol from the sponsor, to the time the first patient was enrolled into a trial at any MMRC participating center. The earlier group (EG) of MMRC trials (n=7) required a mean of 257 calendar days for activation, comparable to the mean published data of 251 calendar days1. The more recent group (RG) of MMRC trials (n=5) required a mean of 158 calendar days for activation, representing a 38% shortening of activation time. Additionally, implementation of standardized processes and rigorous project management resulted in a reduction in activation times for all MMRC centers in a given trial from a mean of 7.5 months to a mean of 5.1 months. Improving the mean time of several several specific steps in the process including time to initial protocol review submission from receipt (EG=37 vs. RG=19 days), scientific review committee time (EG=98 vs. RG=55 days), and the time from trial opening to first patient dosed (EG=74 vs. RG=27 days) contributed to the overall decrease in activation times. The EG metrics data are comparable to published data1 for each process step. Conclusion: The MMRC member institutions have seen substantial improvements in trial activation times and are in the process of implementing additional processes to further improve protocol development and trial conduct metrics. The efficiencies and process improvements realized from application of rigorous MMRC project management resources and the standardization of contracting and other key activities may be applied in other areas of oncology clinical trials beyond multiple myeloma. With increasing numbers of new oncology agents to be evaluated and greater pressure on trial sponsors to introduce efficiencies into trial timelines, overcoming such barriers is of critical importance. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B58.

AbstractBackgroundCardiac complications following hematopoietic stem cell transplantation (HSCT) are emerging as a significant concern given the increasing utilization of HSCT for a variety of hematologic malignancies.MethodsWe utilized an existing database to determine the frequency of cardiac dysfunction (CD), namely a decrease in left ventricular ejection fraction, following conditioning with high‐dose melphalan (HDM) and autologous HSCT for multiple myeloma (MM) and systemic amyloidosis (AL). We then performed a case–control study to examine variables associated with increased risk of CD in this population.ResultsIn MM patients undergoing HSCT, the rate of CD was 1.6% (17/1050, 95% CI: [0.9, 2.6]). None of the examined pre‐HSCT variables or HDM dose were significantly associated with development of CD in this population. In patients with AL, the rate of CD was 5.6% (24/426, 95% CI: [3.6, 8.3]). On univariate analysis, decision to administer an HDM dose <200 mg/m2 [odds ratio (OR): 4.59 (1.27–16.57) P = 0.02], pretransplant left ventricular ejection fraction <60% [OR: 17.78 (2.29–138.33) P = 0.006], and documented amyloid involvement of ≥3 organs [OR: 4.0 (1.03–15.6) P = 0.046] were associated with the development of CD in the AL population. No other examined peri‐transplant factors were associated with development of CD.ConclusionTo our knowledge, this is the first series to report a significant rate of CD following HDM conditioning and autologous HSCT in patients with AL.

AbstractThe POEMS syndrome (polyradiculoneuropathy, organomegaly, multiple endocrinopathies, monoclonal protein, skin changes) is a rare disease associated with a plasma cell dyscrasia. Patients with disseminated POEMS can be treated with high-dose therapy and autologous stem cell transplantation (ASCT). While clinical improvement is nearly universal in these patients, the long-term outcomes after transplantation are unclear. We therefore assessed the long-term clinical outcomes of 59 POEMS patients treated with ASCT at our institution. With a median follow-up of 45 months, 14 patients have progressed with a progression-free survival of 98% and 75% at 1 and 5 years, respectively. Factors associated with progression have included an IgG-λ monoclonal component (hazard ratio [HR] 7.5; 95% confidence interval [CI], 2.3-28.3; P = .0008), fluorodeoxyglucose-avid lesions on baseline positron emission tomography (HR 6.4; 95% CI, 1.2-120; P = .03), lack of complete hematologic response (HR 5.4; 95% CI, 1.8-16.7; P = .003), and patients aged 50 years or younger at transplantation (HR 4.4; 95% CI, 1.3-20; P = .01). The most common progression events have been radiologic followed by rising VEGF. Symptomatic progression has been rare. Most patients could be salvaged with immunomodulatory drugs or radiation. The 5-year survival is 94%. Herein, we describe a system of monitoring response and progression among patients with POEMS after ASCT.

Abstract CN03-03 Multiple myeloma is the second most common hematological malignancy, affecting nearly 20,000 individuals each year with nearly 12,000 deaths during the same period. While considerable progress has been made in the treatment of this disease and the survival has improved in the recent years, myeloma still remains incurable. Given the incurable nature of the disease there has been considerable interest in understanding the pathogenesis and evolution of monoclonal gammopathies, which can improve the prospects for effective prevention strategies. Monoclonal gammopathy of undetermined significance has been recognized as precursor state for development of multiple myeloma for years. The prevalence of MGUS increases with age and forms nearly two thirds of the patients with a diagnosis of monoclonal gammopathy. The risk of progression from MGUS to myeloma has studied in several large cohort studies and is estimated to be around 1% per year. This risk remains fairly constant over the lifetime, highlighting the possibility that a ‘second hit’ is required in an individual with MGUS for its evolution to myeloma. Several clinical features have been identified that increases the risk of progression in any given individual, including the immunoglobulin isotype, M protein concentration, circulating plasma cells, and suppression of uninvolved immunoglobulin. More recently, the introduction of assays that can detect free light chains unbound to the heavy chain has allowed better identification of patients at increased risk of progression to myeloma. In fact, a staging system that incorporates the type of immunoglobulin, its concentration and presence of abnormal light chain ration allows us to identify a proportion of patients that are at high risk of progression. However, more recent epidemiologic studies suggest that nearly all patients with myeloma have a MGUS phase prior to the development of myeloma. This finding reinforces the importance of evaluating strategies that prevent the progression from MGUS to symptomatic myeloma. In addition, many patients are diagnosed with smoldering myeloma, a condition that falls between MGUS and symptomatic myeloma, and one which is typically observed with out any proven effective interventions. As in MGUS, there are several features that have been identified that allow risk stratification these patients. While patients with smoldering myeloma have several fold risk of progression compared to MGUS, it provides another point in the disease spectrum where prevention strategies may be valuable. The biggest obstacle to pursuing prevention strategies in patients with MGUS has been the low overall risk of progression, thus compromising the risk benefit ratio for most available anti-myeloma strategies to be used in a preventive fashion. Ongoing studies, especially that are examining potential genetic markers of progression, may allow better determination of an individual’s risk allowing us to focus on the small proportion of individuals with the highest level of risk. Another option would be to examine interventions with none or minimal adverse effects, that would allow a more universal approach to prevention. These could include vaccination strategies to modulate the immune system, use of food supplements and other measures which are being currently being evaluated. Given the much higher risk of progression among patients with smoldering myeloma, there have been clinical trials evaluating the role of anti-myeloma drugs as a strategy for preventing progression to symptomatic myeloma. Thalidomide has been studied with variable success. Clinical trials are being planned to evaluate the role of lenalidomide, an immunomodulatory analogue of thalidomide. Citation Information: Cancer Prev Res 2008;1(7 Suppl):CN03-03.

Abstract Light-chain (AL) amyloidosis remains incurable despite recent therapeutic advances. Given the activity of the lenalidomide-alkylating agent combination in myeloma, we designed this phase 2 trial of lenalidomide, cyclophosphamide, and dexamethasone in AL amyloidosis. Thirty-five patients, including 24 previously untreated, were enrolled. Nearly one-half of the patients had cardiac stage III disease and 28% had ≥ 3 organs involved. The overall hematologic response (≥ partial response [PR]) rate was 60%, including 40% with very-good partial response or better. Using serum-free light chain for assessing response, 77% of patients had a hematologic response. Organ responses were seen in 29% of patients and were limited to those with a hematologic response. The median hematologic progression-free survival was 28.3 months, and the median overall survival was 37.8 months. Hematologic toxicity was the predominant adverse event, followed by fatigue, edema, and gastrointestinal symptoms. A grade 3 or higher toxicity occurred in 26 patients (74%) including ≥ grade 3 hematologic toxicity in 16 patients (46%) and ≥ grade 3 nonhematologic toxicity in 25 patients (71%). Seven patients (20%) died on study, primarily because of advanced disease. Lenalidomide, cyclophosphamide, and dexamethasone (CRd) is an effective combination for treatment of AL amyloidosis and leads to durable hematologic responses as well as organ responses with manageable toxicity. The trial was registered at www.clinicaltrials.gov (NCT00564889).

Abstract Emerging evidence indicates that tumors can follow several evolutionary paths over a patient's disease course. With the use of serial genomic analysis of samples collected at different points during the disease course of 28 patients with multiple myeloma, we found that the genomes of standard-risk patients show few changes over time, whereas those of cytogenetically high-risk patients show significantly more changes over time. The results indicate the existence of 3 temporal tumor types, which can either be genetically stable, linearly evolving, or heterogeneous clonal mixtures with shifting predominant clones. A detailed analysis of one high-risk patient sampled at 7 time points over the entire disease course identified 2 competing subclones that alternate in a back and forth manner for dominance with therapy until one clone underwent a dramatic linear evolution. With the use of the Vk*MYC genetically engineered mouse model of myeloma we modeled this competition between subclones for predominance occurring spontaneously and with therapeutic selection.