Histone deacetylase inhibition in combination with MEK or BCL-2 inhibition in multiple myeloma

Despite recent advances in the treatment of multiple myeloma, patients with this disease still inevitably relapse and become refractory to existing therapies. Mutations in K-RAS, N-RAS and B-RAF are common in multiple myeloma, affecting 50% of patients at diagnosis and >70% at relapse. However, targeting mutated RAS/RAF via MEK inhibition is merely cytostatic in myeloma and largely ineffective in the clinic. We examined mechanisms mediating this resistance and identified histone deacetylase inhibitors as potent synergistic partners. Combining the MEK inhibitor AZD6244 (selumetinib) with the pan-histone deacetylase inhibitor LBH589 (panobinostat) induced synergistic apoptosis in RAS/RAF mutated multiple myeloma cell lines. Interestingly, this synergy was dependent on the pro-apoptotic protein BIM. We determined that while single-agent MEK inhibition increased BIM levels, the protein remained sequestered by antiapoptotic BCL-2 family members. LBH589 dissociated BIM from MCL-1 and BCL-XL, which allowed it to bind BAX/BAK and thereby initiate apoptosis. The AZD6244/LBH589 combination was specifically active in cell lines with more BIM:MCL-1 complexes at baseline; resistant cell lines had more BIM:BCL-2 complexes. Those resistant cell lines were synergistically killed by combining the BH3 mimetic ABT-199 (venetoclax) with LBH589. Using more specific histone deacetylase inhibitors, i.e. MS275 (entinostat) and FK228 (romidepsin), and genetic methods, we determined that concomitant inhibition of histone deacetylases 1 and 2 was sufficient to synergize with either MEK or BCL-2 inhibition. Furthermore, these drug combinations effectively killed plasma cells from myeloma patients ex vivo. Given the preponderance of RAS/RAF mutations, and the fact that ABT-199 has demonstrated clinical efficacy in relapsed/refractory multiple myeloma, these drug combinations hold prom ise as biomarker-driven therapies

Adjusting for subsequent therapies in the TOURMALINE-MM1 study shows clinically meaningful improvement in overall survival with addition of ixazomib to lenalidomide and dexamethasone

TOURMALINE-MM1, the only blinded randomized study in patients with relapsed and/or refractory multiple myeloma (RRMM; ≥1 prior therapy) in the last 10 years, investigated ixazomib+lenalidomide+dexamethasone (IRd) versus lenalidomide+dexamethasone (Rd). Final overall survival (OS) data were based on a median follow-up of 85 months. In RRMM trials where patients have had 1-3 relapses after initial treatment, a high proportion receive subsequent therapy. Application of salvage therapies in blinded trials and newer modes of therapy can increasingly complicate the interpretation of OS. This analysis explores the impact of subsequent therapies on OS outcomes in TOURMALINE-MM1. The inverse probability of censoring weights (IPCW) method, marginal structural model (MSM), and rank preserving structural failure time model (RPSFTM) were utilized to adjust for confounding on OS, introduced by subsequent therapies. Analyses were conducted for the intentto-treat (ITT) population and ≥2 prior lines subgroup. Unadjusted hazard ratio (HR) for IRd versus Rd was 0.94 (95% confidence interval [CI]: 0.78-1.13) in the ITT population. After adjusting for the impact of subsequent therapies by the RPSFTM method, estimated HR for IRd versus Rd in the ITT population was 0.89 (95% CI: 0.74-1.07). Adjusting with IPCW and MSM methods also showed an improvement in HR, favoring IRd. IRd may be particularly beneficial in patients with ≥2 prior lines of therapy (IPCW and MSM HR=0.52, 95% CI: 0.30-0.88; RPSFTM HR=0.68, 95% CI: 0.51-0.91). These analyses highlight the growing challenge of demonstrating OS benefit in multiple myeloma patients and the importance of assessing confounding introduced by subsequent therapies when interpreting OS

A gene expression signature distinguishes innate response and resistance to proteasome inhibitors in multiple myeloma

Extensive interindividual variation in response to chemotherapy is a major stumbling block in achieving desirable efficacy in the treatment of cancers, including multiple myeloma (MM). In this study, our goal was to develop a gene expression signature that predicts response specific to proteasome inhibitor (PI) treatment in MM. Using a well-characterized panel of human myeloma cell lines (HMCLs) representing the biological and genetic heterogeneity of MM, we created an in vitro chemosensitivity profile in response to treatment with the four PIs bortezomib, carfilzomib, ixazomib and oprozomib as single agents. Gene expression profiling was performed using next-generation high-throughput RNA-sequencing. Applying machine learning-based computational approaches including the supervised ensemble learning methods Random forest and Random survival forest, we identified a 42-gene expression signature that could not only distinguish good and poor PI response in the HMCL panel, but could also be successfully applied to four different clinical data sets on MM patients undergoing PI-based chemotherapy to distinguish between extraordinary (good and poor) outcomes. Our results demonstrate the use of in vitro modeling and machine learning-based approaches to establish predictive biomarkers of response and resistance to drugs that may serve to better direct myeloma patient treatment options

A Validated Composite Organ and Hematologic Response Model for Early Assessment of Treatment Outcomes in Light Chain Amyloidosis

Newly diagnosed AL amyloidosis patients were evaluated to develop a model for early assessment of treatment benefit at 6 months, integrating both hematologic (HR) and organ response (OR) assessment (testing cohort, Mayo: n = 473; validation cohort, Pavia: n = 575). Multiple OR were assessed as follows: All OR (AOR): response in all organs, mixed OR (MOR): response in some organs, no OR (NOR)]. AOR rates at 6 months improved with deepening HR; complete response (CR; 38%, 35%), very good partial response (VGPR; 30%, 26%), and partial response (PR; 16%, 21%), respectively. A composite HR/OR (CHOR) model was developed using incremental scoring based on hazard ratios with scores of 0-3 for HR (0-CR, 1-VGPR, 2-PR, 3-no response) and 0-2 for OR (0-AOR, 1-MOR, 2-NOR). Patients could be divided into two distinct CHOR groups (scores 0-3 and 4-5), with median OS in group 1 and group 2: Not reached vs. 34 months, p \u3c 0.001 [Mayo] and 87 vs. 23 months, p \u3c 0.001 [Pavia]. In conclusion, we developed a model that can assess multiple organs concurrently, and integrate both HR and OR assessments to determine early clinical benefit with treatment, which may be used as a surrogate end-point in trials and to compare outcomes with different therapies

Interpreting clinical trial data in multiple myeloma: translating findings to the real-world setting

Substantial improvements in survival have been seen in multiple myeloma (MM) over recent years, associated with the introduction and widespread use of multiple novel agents and regimens, as well as the emerging treatment paradigm of continuous or long-term therapy. However, these therapies and approaches may have limitations in the community setting, associated with toxicity burden, patient burden, and other factors including cost. Consequently, despite improvements in efficacy in the rigorously controlled clinical trials setting, the same results are not always achieved in real-world practice. Furthermore, the large number of different treatment options and regimens under investigation in various MM settings precludes the feasibility of obtaining head-to-head clinical trial data, and there is a temptation to use cross-trial comparisons to evaluate data across regimens. However, multiple aspects, including patient-related, disease-related, and treatment-related factors, can influence clinical trial outcomes and lead to differences between studies that may confound direct comparisons between data. In this review, we explore the various factors requiring attention when evaluating clinical trial data across available agents/regimens, as well as other considerations that may impact the translation of these findings into everyday MM management. We also investigate discrepancies between clinical trial efficacy and real-world effectiveness through a literature review of non-clinical trial data in relapsed/ refractory MM on novel agent−based regimens and evaluate these data in the context of phase 3 trial results for recently approved and commonly used regimens. We thereby demonstrate the complexity of interpreting data across clinical studies in MM, as well as between clinical studies and routine-care analyses, with the aim to help clinicians consider all the necessary issues when tailoring individual patients’ treatment approaches

Serial measurements of circulating plasma cells before and after induction therapy have an independent prognostic impact in patients with multiple myeloma undergoing upfront autologous transplantation

Circulating plasma cells at diagnosis, prior to auto-transplant and at relapse have a negative impact on survival in multiple myeloma. However, the impact of kinetics of circulating plasma cells along the course of illness has not been defined. We have analyzed 247 newly diagnosed multiple myeloma patients undergoing early auto-transplant who had paired evaluation of circulating plasma cells at diagnosis and pre-transplant by 6-color flow cytometry. A total of 117 patients had no detectable circulating plasma cells at both time points (CPC−/−), 82 had circulating plasma cells at diagnosis followed by complete eradication after induction (CPC+/−) and 48 had circulating plasma cells at transplant, including persistence of cells (CPC+/+; n=45) or emergence of new cells (CPC−/+; n=3) after induction. The rate of post-transplant stringent complete response was 32% in the CPC−/−, 30% in CPC+/− and 12% in CPC+/+ or −/+ groups (P=0.018). At a median follow up of 58 months from transplantation, the median progression-free survival in the 3 respective groups were 30, 24 and 14 months, and the 5-year overall survival rates were 83%, 70% and 43% (

Plasma cell proliferative index predicts outcome in immunoglobulin light chain amyloidosis treated with stem cell transplantation

The plasma cell proliferative index provides an insight into plasma cell biology in plasma cell disorders and is an important prognostic marker in myeloma and smoldering myeloma. We analyzed the prognostic impact of the plasma cell proliferative index in 513 patients with systemic immunoglobulin light chain (AL) amyloidosis undergoing stem cell transplantation at the Mayo Clinic between 1st January 2003 and 31st August 2016. Two cohorts were identified according to Low or Elevated plasma cell proliferative index. Patients with an Elevated plasma cell proliferative index had more cardiac involvement (56% vs. 44%; P=0.01), less renal involvement (55% vs. 70%; P=0.001), and were more likely to have 10% or over bone marrow plasma cells (58% vs. 32%;

Activity of pomalidomide in patients with immunoglobulin light-chain amyloidosis

Immunoglobulin light-chain (AL) amyloidosis is a rare, incurable plasma cell disorder. Its therapy has benefited immensely from the expanding drug armamentarium available for multiple myeloma. Pomalidomide in combination with weekly dexamethasone (Pom/dex) is active among patients with relapsed myeloma. In the present study, we explored the Pom/dex combination in patients with previously treated AL. Patients were eligible for this prospective phase 2 trial if they had had at least one prior regimen and if they had reasonably preserved organ function. Patients were treated with oral Pom/dex. Thirty-three patients were enrolled. The median age was 66 years. Median time from diagnosis to on-study was 37 months. Eighty-two percent had cardiac involvement. The confirmed hematologic response rate was 48%, with a median time to response of 1.9 months. Organ improvement was documented in 5 patients. The median overall and progression-free survival rates were 28 and 14 months, respectively; the 1-year overall and progression-free survival rates were 76% and 59%, respectively. There was a discordance between the hematologic response and the N-terminal probrain natriuretic peptide response. The most common grade 3-5 adverse events, regardless of attribution, were neutropenia and fatigue. We conclude that pomalidomide appears to be a valuable drug covering an unmet clinical need in patients with previously treated AL. The trial is registered at www.clinicaltrials.gov as NCT00558896. (Blood. 2012;119(23): 5397-5404

Polymorphisms within autophagy-related genes as susceptibility biomarkers for multiple myeloma: a meta-analysis of three large cohorts and functional characterization

Functional data used in this project have been meticulously catalogued and archived in the BBMRI-NL data infrastructure (https://hfgp.bbmri.nl/, accessed on 12 February 2020) using the MOLGENIS open-source platform for scientific data.Multiple myeloma (MM) arises following malignant proliferation of plasma cells in the bone marrow, that secrete high amounts of specific monoclonal immunoglobulins or light chains, resulting in the massive production of unfolded or misfolded proteins. Autophagy can have a dual role in tumorigenesis, by eliminating these abnormal proteins to avoid cancer development, but also ensuring MM cell survival and promoting resistance to treatments. To date no studies have determined the impact of genetic variation in autophagy-related genes on MM risk. We performed meta-analysis of germline genetic data on 234 autophagy-related genes from three independent study populations including 13,387 subjects of European ancestry (6863 MM patients and 6524 controls) and examined correlations of statistically significant single nucleotide polymorphisms (SNPs; p < 1 × 10−9) with immune responses in whole blood, peripheral blood mononuclear cells (PBMCs), and monocyte-derived macrophages (MDM) from a large population of healthy donors from the Human Functional Genomic Project (HFGP). We identified SNPs in six loci, CD46, IKBKE, PARK2, ULK4, ATG5, and CDKN2A associated with MM risk (p = 4.47 × 10−4−5.79 × 10−14). Mechanistically, we found that the ULK4rs6599175 SNP correlated with circulating concentrations of vitamin D3 (p = 4.0 × 10−4), whereas the IKBKErs17433804 SNP correlated with the number of transitional CD24+CD38+ B cells (p = 4.8 × 10−4) and circulating serum concentrations of Monocyte hemoattractant Protein (MCP)-2 (p = 3.6 × 10−4). We also found that the CD46rs1142469 SNP corre lated with numbers of CD19+ B cells, CD19+CD3− B cells, CD5+ IgD− cells, IgM− cells, IgD−IgM− cells, and CD4−CD8− PBMCs (p = 4.9 × 10−4−8.6 × 10−4 ) and circulating concentrations of interleukin (IL)-20 (p = 0.00082). Finally, we observed that the CDKN2Ars2811710 SNP correlated with levels of CD4+EMCD45RO+CD27− cells (p = 9.3 × 10−4 ). These results suggest that genetic variants within these six loci influence MM risk through the modulation of specific subsets of immune cells, as well as vitamin D3−, MCP-2−, and IL20-dependent pathways.This work was supported by the European Union’s Horizon 2020 research and innovation program, N° 856620 and by grants from the Instituto de Salud Carlos III and FEDER (Madrid, Spain; PI17/02256 and PI20/01845), Consejería de Transformación Económica, Industria, Conocimiento y Universidades and FEDER (PY20/01282), from the CRIS foundation against cancer, from the Cancer Network of Excellence (RD12/10 Red de Cáncer), from the Dietmar Hopp Foundation and the German Ministry of Education and Science (BMBF: CLIOMMICS [01ZX1309]), and from National Cancer Institute of the National Institutes of Health under award numbers: R01CA186646, U01CA249955 (EEB).This work was also funded d by Portuguese National funds, through the Foundation for Science and Technology (FCT)—project UIDB/50026/2020 and UIDP/50026/2020 and by the project NORTE-01-0145-FEDER-000055, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)