ALBERT

Description: Introduction: Emerging evidence supports that cytogenetic abnormalities (CAs) drive myelomagenesis and heterogeneity (e.g., clinical presentation, response to therapy, and prognosis) of multiple myeloma (MM). Diversity of CAs, including primary (IgH translocations and trisomies) and secondary CAs (copy number abnormalities) argues that MM is not a "single disease". Thus, identification of CAs at diagnosis is essential for risk stratification, guiding treatment, and prognostic estimation in daily practice. However, although frequency, configuration, and significance of CAs have been well documented in the Western countries, this information is lacking in the Asian population. To this end, a multi-center retrospective analysis was carried out to examine epidemiology and prognostic significance of CAs alone or in combination in a cohort of Chinese patients with newly-diagnosed MM (NDMM). Materials and Methods: A total of 1015 NDMM patients who had the baseline information of CAs detected by FISH at four institutes nationwide were included. According to the IMWG consensus updated in 2016, 1q gain, del(17p), t[4;14], and t[14;16] were defined as high-risk CAs (HRCAs), while another HRCA t[14;20] was not tested routinely in a majority of these patients. In addition, del(1p) and del(13q14) were considered as an adverse CA. According to the mSMART3.0 proposed by Mayo Clinic in 2018, double-hit (DHMM) and triple-hit MM (THMM) were defined as co-occurrence of 2 or 〉= 3 HRCAs, respectively. The Kaplan-Meier approach was used to estimate progression-free survival (PFS) and overall survival (OS). Results: In this cohort, the median age of 1015 patients was 61 years; 63.5% were male. The type of IgG, light chain, IgA, IgD, non/oligosecretory, IgM, or IgE accounted for 42.9%, 26.2%, 24.5%, 3.4%, 2.5%, 0.4%, and 0.1%, respectively. Del(13q) (46.4%) and 1q gain (46.1%; 3 copies = 73.8%, 〉= 4 copies = 26.2%) represented the most common CAs, followed by t(4;14) (14.0%), t(11;14) (11.8%), del(1p) (11.5%), del(17p) (9.9%; 20-50% cells = 35.6%, 〉 50% cells = 64.4%), and t(14;16) (5.1%). While none of these CAs was detected in 23.8% of cases, the frequency of patients who carried 1 - 5 CAs was 31.9%, 28.0%, 13.4%, 2.0%, and 0.9%, respectively. In the 1q+ cases, 36.4% patients carried second CA(s), including del(13q) (61.1%), t(4;14) (20.3%), del(1p) (14.8%), del(17p) (10.7%), t(11;14) (10.4%), and t(14;16) (8.1%). In the del(17p) cases, 57.5% patients had additional CA(s), including del(13q) (75.2%), 1q gain (49.5%), del(1p) (21.6%), t(4;14) (19.6%), t(14;16) (8.7%), and t(11;14) (2.2%). In the cases bearing IgH translocations, 26.0% patients also carried other CA(s), including del(13q) and 1q gain (61.9% for each), and del(17p) (9.3%). In the cases harboring HRCAs, the percentage of patients who carried 1 - 4 HRCAs was 70.2%, 24.8%, 3.7%, and 1.1%, respectively. Overall, 14.3% and 2.9% patients had DHMM or THMM, of whom 65.0%, 18.0%, 12.0%, and 5.0% had 2 - 5 HRCAs, respectively. While there was no significant difference in PFS between the cases carrying 1 and 2 CAs (P = 0.209), the patients who had 3 or more CAs displayed a sharp reduction in median PFS (P = 0.022 and P = 0.003 for 3 vs 1 or 2 CAs). Although multiple CAs was associated with shorter median OS, no statistical significance was observed for each comparison (P 〉 0.05). However, patients who carried 〉= 2 HRCAs had significantly shorter median PFS (12.1 months; P = 0.0004) and OS (29.3 months; P = 0.027) than those who had one single HRCA (32.2 and 65.6 months for median PFS and OS). Conclusion: In comparison with the Western countries, the incidence of secondary HRCAs (e.g., 1q gain and del(17p)) is relatively higher in Chinese patients at diagnosis, while the standard-risk CA such as t(11;14) is clearly less frequent. The proportion of Chinese patients who carry multiple CAs (up to 5) or HRCAs appear to be greater as well. In this context, patients carrying two or more HRCAs, so called DHMM or THMM, exhibit significantly worse outcome than those carrying only one HRCA. Together, this study builds up an up-to-date profile of CAs for Chinese patients, which might lay a foundation for revising the criteria for risk stratification and the guideline for treatment that is more feasible and practicable in China. It also provides the information about frequency and configuration of MM-driven CAs, which might be more relevant to the Asian population. Disclosures Kumar: Takeda: Research Funding; Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding.

Description: Background: Multiple Myeloma (MM) is a disease of the elderly, whose prognoses are highly heterogeneous. Hence International Myeloma Working Group (IMWG) proposed geriatric assessment (GA) in 2015, including daily activity and comorbidity status, to better discriminate between fit and frail patients (Palumbo et al, 2015). However, IMWG recruited patients from clinical trials instead of real world practices. Therefore we studied GA in elderly MM patients consecutively in China, along with other perspectives which are known to be problematic in elderly population that were previously left unnoticed, such as nutrition status, risk of cognitive impairment, risk of depression, and quality of life. Aim: Our study centers on the feasibility to perform a more comprehensive geriatric assessment (cGA) in elderly MM patients, current cGA status in elderly MM patients in China, and the cGA difference between Chinese patients and patients in the IMWG study. Method: From August 2017 to April 2019, we continuously recruited 336 newly diagnosed elderly (age ≥ 65) MM patients from 21 centers in China. cGA was performed at diagnosis, after treatment cycle 1, after cycle 4, and 1 year after treatment. cGA includes physical conditions (ECOG), activities of daily living (ADL), instrumental ADL (IADL), mini-nutritional assessment (MNA-SF), geriatric depression scale (GDS), mini-mental state examination (MMSE), quality of life (SF-36) and Charlson comorbidity index (CCI). Staging was assessed at baseline (International Staging System (ISS) & Revised ISS) and hematological responses were evaluated along with each cGA timepoint. Results: We pool-analyzed data of 336 newly-diagnosed elderly MM patients. The median age was 70 (range 65-88) and 25.5% of patients were older than 75 years. 336 (100%) patients were able to complete cGA, and median assessment time was 40 minutes (range 20-70). Upon diagnosis, only 34% and 37.5% of patients had full ADL and IADL respectively. 38.5% of patients had moderate to high risk of depression (GDS ≥ 6). 13.2% of patients were malnourished (MNA-SF ≤ 7), while 46.3% of patients were at risk of malnutrition (8 ≤ MNA-SF ≤ 11). 41% of patients had at least one comorbidity (CCI ≥ 1). 45.7% of patients had moderate to intermediate risk of cognitive impairment (MMSE ≤ 26). Grouping by IMWG-GA index, our study identified 59.9% patients in frail group (vs 39% in IMWG study), 15.8% in intermediate (vs 31% in IMWG) and 24.3% in fit (vs 30% in IMWG). 69% of patients received proteasome inhibitor-containing regimens and 20.7% of patients received lenalidomide-containing regimens. Best hematological responses in fit and intermediate groups were better than responses in frail group (≥ PR rate: 88.5% in fit, 94.4% in intermediate vs 77.5% in frail). Median follow up time was 10 months. To date, 215 (64%) patients have finished the cGA after cycle 1; 164 (48.8%) patients have finished the cGA after cycle 4; 91 (27.1%) patients has finished all 4 planned cGA and improvements in cGA were observed in the majority of these patients. Conclusion: Our study showed significant CGA heterogeneity in elderly MM patients. Even in the IMWG-GA "fit" group, nutrition, depression and cognitive impairment remain problems. Frail patients took up a larger proportion in Chinese elderly MM patients compared to IMWG study. Our study strongly justifies the necessity for cGA in elderly patients with MM, more so in the real world MM patients than in the clinical trials. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 4948 Objective To investigate the efficacy and safety of PAD (bortezomib, doxorubicin and dexamethasone) combination therapy for Chinese relapsed or refractory multiple myeloma (MM). Methods 31 patients with relapsed or refractory MM received two to eight 21-days cycles of PAD: comprising an intravenous bolus of bortezomib 1.3 mg/m2 (P1,N=13) or 1.0 mg/m2 (P2,N=18) on days 1, 4, 8, and 11, doxorubicin 10mg per day on days 1 to 4, along with dexamethasone 40mg on days 1-4. Response to PAD was evaluated according to International Myeloma Working Group Criteria (IMWG 2006), toxicity was graded according to NCI CTCAE v3.0. Results 25 patients (80.6%) achieved at least a partial response (PR), including complete response (CR) in 9 patients (29%), very good partial response (VGPR) in 7 patients (22.6%), PR in 9 patients (29%) and stable disease (SD) in 4 patients(12.9%), progression of disease (PD) in 2 patients (6.5%); median time to progression was 9.2 months, the median courses to achieve at least PR was 1.6(1-3) cycles, all of 7 patients with extramedullary plasmacytoma achieved at least PR after the first cycle of PAD, extramedullary plasmacytoma disappeared with 1-2 cycles of PAD. The efficacy was independent of traditional prognostic factors such asβ2-MG, Albumin,LDH and Hemoglobin which have previously influenced response to traditional chemotherapy. 1.5 year OS (Overall survival)of CR+VGPR group and PR group were 87.5% vs 46.7% (P=0.09). ≥PR response rate (CR +VGPR +PR) of P1AD and P2AD were 84.6% VS 77.8% (P= 0.501), CR+VGPR rate of P1AD and P2AD were 53.8% vs 50.0% (P=0.561 ). 1 year PFS(Progession-free survival) of P1AD and P2AD were 61.2% vs 55.6%(P=0.638), there were not difference between P1AD and P2AD in response rate(P= 0.501) and 1 year OS (P=0.872). Adverse events included thrombocytopenia in 15 patients ( 48.4% ), leukopenia in 8 patients(25.8%), peripheral neuropathy in 6 patients (19.4% ), varicella herpes zoster in 7 patients (22.6%), fatigue in 11 patients (35.5%) and diarrhea in 5 patients (16.1%), Thrombocytopenia and peripheral neuropathy of P1AD and P2AD were 46.2% vs 11.1%( P=0.037)and 53.8% vs 11.1%(P= 0.014).Common adverse reactions could be controlled with routine supportive treatmemt, one patient (3.2% ) died from respiratory failure during his fifth P1〉AD. Conclusions PAD should be considered an appropriate treatment for Chinese relapsed or refractory MM, especially for MM with extramedullary plasmacytoma, its efficacy were independent of traditional prognosis factors, bortezomib dose reduction may reduce toxicities of PAD while retaining the efficacy. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 5077 The RhoA effector mDia1 is involved in controlling the balance between filamentous and monomeric actin, but its role in modulating thrombin-induced actin remodeling and platelet spreading on fibrinogen matrices remains unclear. In this study, mDia1 was shown to translocate to the platelet cytoskeleton following thrombin stimulation, in a phosphoinositide 3-kinase (PI 3-kinase)-dependent manner. AntimDia1 loading or pretreatment with PI 3-kinase inhibitors essentially abrogated thrombin-elicited actin stress fiber formation, with a corresponding decrease in the proportion of platelets exhibiting a fully spread morphology. We also investigated the mechanisms underlying the effects of mDia1 on thrombin-induced actin remodeling and platelet spreading, and found that these involved PI 3-kinase-mediated induction of mDia1 interaction with RhoA. Collectively, these results suggest that the PI 3-kinase/RhoA/mDia1 axis is a critical pathway for coupling thrombin signaling to actin cytoskeletal remodeling during platelet spreading. Disclosures No relevant conflicts of interest to declare.

Description: Isocitrate dehydrogenase (IDH) mutations are common genetic alterations in myeloid disorders, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Epigenetic changes, including abnormal histone and DNA methylation, have been implicated in the pathogenic build-up of hematopoietic progenitors, but it is still unclear whether and how IDH mutations themselves affect hematopoiesis. Here, we show that IDH1-mutant mice develop myeloid dysplasia in that these animals exhibit anemia, ineffective erythropoiesis, increased immature progenitor and erythroblast. In erythroid cells of these mice, D-2-hydroxyglutarate (D-2HG), an aberrant metabolite produced by the mutant IDH1 enzyme, inhibits oxoglutarate dehydrogenase (OGDH) activity and diminishes succinyl-CoA production. This succinyl-CoA deficiency attenuates heme biosynthesis in IDH1-mutant hematopoietic cells, thus blocking erythroid differentiation at the late erythroblast stage and the erythroid commitment of hematopoietic stem cells (HSC), while the exogenous succinyl-CoA or 5-ALA rescues erythropoiesis in IDH1-mutant erythroid cells. Heme deficiency also impairs heme oxygenase-1 (HO-1) expression, which reduces levels of important heme catabolites such as biliverdin and bilirubin. These deficits result in accumulation of excessive reactive oxygen species (ROS) that induce the cell death of IDH1-mutant erythroid cells. Our results clearly demonstrate the essential role of IDH1 in normal erythropoiesis and show how its mutation leads to myeloid disorders. Our data thus have important implications for the devising of new treatments for IDH-mutant tumors.