ALBERT

Description: Introduction: Full cycles of R-CHOP chemotherapy or abbreviated chemotherapy followed by radiotherapy are recommended as standard of care for limited stage (LS) diffuse large B-cell lymphoma (DLBCL). There are occasions when lesions are completely excised during the diagnostic surgical resection. In addition, initial surgical resection of the involved area is often performed in the treatment of intestinal lymphomas with LS disease due to obstructive lesions or perforation risk. As to these patients without residual gross lesions, however, the number of cycles of chemotherapy has not so far been questioned and full cycles of chemotherapy are usually performed. Thus, we aimed to investigate the effectiveness of an abbreviated three courses of R-CHOP chemotherapy in patients with completely excised stage I or II CD20+ DLBCL. Methods: This is a multicenter, single arm, phase 2 study designed to evaluate efficacy and safety of 3 cycles of R-CHOP chemotherapy in low risk LS DLBCL. Key inclusion criteria were as follows: pathologically confirmed CD20 positive DLBCL, age 〉18 years, stage I or II, and complete resection with no residual lesion after surgical resection. Patients with B symptoms, bulky disease, primary breast, testicular or CNS lymphomas were excluded. R-CHOP chemotherapy started within 6 weeks from surgical resection and was repeated every 3 weeks for 3 cycles. Prophylactic G-CSF was not administered. Radiologic tumor assessment was performed at baseline, every 3 months until 2 years, then every 6 months until 5 years after completion of study treatment. The primary endpoint was 2-year disease-free survival (DFS). Secondary endpoints included overall survival and safety. (ClinicalTrials.gov: NCT01279902.) Results: Twenty-three patients were enrolled between Dec 2010 and May 2013. Of these, one was excluded because of ineligibility and the remaining 22 patients were included in the analysis. The median age at diagnosis was 57 years (range, 29-77 years). Fourteen patients had stage 1 disease and the other eight had stage 2. Preoperative LDH level was available in 11 patients and it was elevated in two of them. Thus, preoperative IPI scores could be calculated in those 11 patients; 0 in 8, 1 in one, and 2 in one patients, respectively. Postoperative IPI scores were 0 in 11, 1 in 10 and 2 in one patients. Primary sites included intestine (n=15), cervical lymph nodes (n=4), stomach (n=1), tonsil (n=1) and spleen (n=1). All the 22 patients completed 3 cycles of R-CHOP chemotherapy as planned. With a median follow-up of 39.5 months (95% CI, 29.9-47.1 months), only one patient showed disease progression and died with the estimated 2-year DFS and OS rates of 95.0%. It was the only one patient with IPI of 2 with elevated LDH and age〉60 that showed disease progression at 12.7 months. He had a splenic mass and underwent splenectomy followed by 3 cycles of R-CHOP. He underwent one cycle of salvage R-ESHAP chemotherapy but died of rapid disease progression. No grade 3 or 4 non-hematologic toxicities were observed. Neutropenia was the most common grade 3 or 4 hematologic toxicity which was noted in 8 (36.4%) patients. Three patients experienced G3 febrile neutropenia. Conclusions: Three cycles of abbreviated R-CHOP chemoimmunotherapy is an effective and safe therapeutic approach for patients with localized and completely excised DLBCL especially in those with low-risk IPI. Figure 1 Kaplan-Meier curves of (A) disease-free survival and (B) overall survival. (A) (B) Figure 1. Kaplan-Meier curves of (A) disease-free survival and (B) overall survival. / (A). / (B) Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 1219 Poster Board I-241 Background High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) has been evaluated in several trials and has shown feasibility as first-line treatment of primary central nervous system lymphoma (PCNSL). However, the best conditioning regimen is still to be identified and high-dose chemotherapy of busulfan, cyclophosphamide, and etoposide (BuCyE) has not been tried although the regimen was shown to be effective for leukemia and systemic non-Hodgkin's lymphoma. Methods Between May 2005 and November 2008, 12 consecutive patients of PCNSL with pathologic diagnosis of diffuse large-B cell lymphoma were treated with the intent of upfront ASCT at Asan Medical Center, Seoul, Korea. We retrospectively analyzed the results of these patients. The treatment included induction chemotherapy of high-dose methotrexate/cytarabine (Abrey et al., JCO 21:4151, 2003), followed by BuCyE chemotherapy consisting of iv busulfan (3.2mg/kg from day -7 to day -5), iv cyclophosphamide (50mg/kg from day -3 to day -2), and etoposide (200mg/m2 every 12 hours from day -5 to day -4), and ASCT. Whole brain radiotherapy (WBRT) was reserved for patients who failed to achieve complete response (CR) after ASCT. Results Median age was 50 years (range, 33-65) and 9 were male. The test of cerebrospinal fluid (CSF) cytology came out to be positive for 3 patients. Eight patients achieved CR and 4 gained partial response (PR) after induction chemotherapy. All 12 patients managed to complete ASCT. Following ASCT, additional 2 patients gained CR, resulting in total number of 10 patients (83.3%). Patients who failed to reach CR were further treated with WBRT and 2 more patients achieved CR. Median duration of first CR was 12.8 months (95% confidence interval [CI], 4.6-20.9) at a median follow-up of 23.8 months (range, 8.8-50.7). Relapse of disease occurred in 7 patients (58.3%) and 5 of them were given salvage treatment (Table 1). Two patients could regain CR and sustained remission for more than 2 years. Two patients had died of disease at the time of analysis. Median event-free survival (EFS) from the first day of induction chemotherapy was 15.0 months (95% CI, 8.3-21.8) and median overall survival (OS) was not reached. The 2-year OS probability was 78.8% and 2-year EFS was 25.7%. No patient experienced veno-occlusive disease or treatment-related mortality (TRM). Three patients among those who were treated with WBRT or intrathecal chemotherapy developed leukoencephalopathy. Conclusion BuCyE chemotherapy might be an option of conditioning regimen for ASCT considering high CR rate of 83.3% and favorable toxicity profile in the treatment of PCNSL. However, high relapse rate of 58.3% suggests that more optimization of induction and conditioning chemotherapy is still required. Disclosures No relevant conflicts of interest to declare.

Description: Introduction Peripheral T-cell lymphoma (PTCL) is a rare and heterogeneous group of diseases associated with poor prognosis, representing 10-15% of non-Hodgkin lymphomas. Although CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) or CHOP-like regimens are often preferred as 1st line treatment, the treatment outcome is poor with 5-year overall survival (OS) rate of 30-40%. In an effort to improve the survival outcomes of these patients, autologous hematopoietic stem cell transplantation (ASCT) as an upfront consolidative treatment has been proposed for patients achieving partial or complete remission after induction therapy. However, the role of ASCT still remains undefined since no randomized trials have demonstrated survival benefit of ASCT in this setting. To better understand the clinical characteristics, treatment patterns, and outcomes in patients with PTCL, we have conducted a nationwide, multicenter, prospective registry study for newly diagnosed patients with PTCL. Methods Patients with PTCL receiving chemotherapy with curative intent were registered and prospectively monitored (ClinicalTrials.gov, no. NCT02364466). All patients were pathologically diagnosed with PTCL according to the 2008 World Health Organization classification of lymphoid neoplasms. Extranodal NK/T cell lymphoma, cutaneous T cell lymphoma, Mycosis fungoides and Sezary syndrome were excluded. The target number for enrollment was 200, and an interim analysis was previously reported at the time of enrollment of 155 patients (ASH 2017). An updated analysis of 198 patients was performed. Results The median age was 59 years (range, 49-70), 122 patients (61.6%) were male and 168 (84.9%) had ECOG performance status of 0-1. PTCL, not otherwise specified was the most common pathologic subtype (n = 80, 40.4%), followed by angioimmunoblastic T cell lymphoma (n = 60, 30.3%). The most frequently administered 1st line regimen was CHOP or CHOP-like regimen (n = 165, 83.3%), followed by ICE (ifosfamide, carboplatin, and etoposide) or ICE-like regimen (n = 23, 11.6%), and others (n = 10, 5.1%). With a median follow-up duration of 28.2 months (95% CI, 25.6-30.6), 2-yr progression-free survival (PFS) rate was 44.4% (95% CI, 37.5-57.4) and 2-yr OS rate was 64.4% (95% CI, 57.4-72.1). Response evaluation for 1st line regimens were available in 175 patients. Among these patients, there was no significant difference in overall response rate (ORR) and complete response (CR) rate between patients treated with CHOP or CHOP-like vs. ICE or ICE-like regimen (ORR: 73.6 vs. 72.7%, P = 1.000; CR rate: 58.1% vs. 45.5%, P = 0.375). In addition, no significant difference was observed regarding PFS and OS between the two treatment groups (CHOP or CHOP-like vs. ICE or ICE-like; 2-yr PFS rate: 45.2 vs. 38.3%, P = 0.39; 2-year OS rate: 65.7 vs. 50.7% P = 0.43) (Figure 1A, B). Among 121 patients younger than 65 years of age who are eligible for transplantation, autologous hematopoietic stem cell transplantation (ASCT) was performed as an upfront consolidative treatment in 51 patients (42.1%). Patients who received upfront ASCT was associated with significantly better PFS and OS compared with patients who did not, with a 2-yr PFS rate of 52.3 vs. 37.0% (P = 0.032) and 2-yr OS rate of 74.2 vs. 57.1% (P = 0.028), respectively (Figure 2A, B). A total of 81 patients were treated with 2nd line chemotherapy for refractory or relapsed disease, and response evaluation for 2nd line chemotherapy was available in 63 patients. Among these patients ORR and CR rate were 49.2% and 30.2%, respectively. Conclusion Our study demonstrated that survival outcome with current treatment options for patients with PTCL remains poor. Although CHOP or CHOP-like regimens were the most commonly used 1st line regimens, no survival benefit was observed when compared with ICE or ICE-like regimens, suggesting that more efforts are needed to establish a standard 1st line treatment for PTCL. ASCT may provide survival benefit in transplant eligible patients, which warrants further evaluation in randomized controlled trials. Disclosures Yoon: Janssen: Consultancy; MSD: Consultancy; Novartis: Consultancy, Honoraria; Yuhan Pharma: Research Funding; Amgen: Consultancy, Honoraria; Genentech, Inc.: Research Funding; Kyowa Hako Kirin: Research Funding. Kim:F. Hoffmann-La Roche Ltd: Research Funding; Celltrion: Research Funding; Novartis: Research Funding; Donga: Research Funding; Kyowa-Kirin: Research Funding; Novartis: Research Funding; J + J: Research Funding.

Description: Introduction: Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a provisional entity in the 2017 WHO classifications of the lymphoid neoplasms, as it was found that features of MEITL differed from those of enteropathy-associated T-cell lymphoma. It is now considered that MEITL is more prevalent in Asia, and almost all cases of intestinal T-cell lymphoma in Asians might be MEITL. To further elucidate the clinicopathologic features of this new disease entity, we carried out a multicenter, retrospective analysis from 9 tertiary institutes in Korea. Patients and methods: A total of 38 patients who were diagnosed with MEITL between 2002 and 2017 from 9 institutes were included in the analysis. Medical records including age, sex, stage, presenting symptoms, laboratory findings, primary sites, and treatment outcomes were collected. The histopathologic diagnoses were centrally-reviewed by experienced lymphoma histopathologists. The primary end-point of the analysis was overall survival (OS). Results: The median age of the patients was 59 (range, 20 - 84) and 27 patients (71.1%) were male. None of the patients had prior history of Celiac disease. Thirty one patients (81.5%) were stage I-II by the Ann-Arbor classifications, and 28 patients (73.7%) were stage I-II1&2 by the Lugano classifications. The most frequent site of involvement was jejunum (N = 20) followed by ileum (N = 17), and 11 patients had multiple site involvement. In line with the previous reports, most cases expressed CD8 (77.1%) and CD56 (92.1%), and did not expressed CD30 (5.3%), and EBER (6.9%). T-cell intracellular antigen was positive in 14 out of 17 cases (82.4%). The median progression-free survival was 6.9 months (95% CI 4.2 - 9.6), and the median OS was 14.8 months (3.0 - 26.6). Thirty one patients (81.6%) received surgery, and 34 patients (89.5%) received chemotherapy. CHOP (N = 28) was the most frequently used regimen followed by CHOEP (N = 3), and ICE, IMVP-16, and EPOCH (N = 1 each). Complete response (CR) rate was 47.1%, and 14 patients had undergone autologous stem cell transplantation (ASCT). Relapse or progression was documented in 22 cases, and the most frequent site was the primary site (N = 20). Of note, relapse at central nervous system was found in 4 cases. Older age (≥ 55 years), advanced Lugano stage (IIE~IV), not achieving CR, and not receiving ASCT were associated with adverse OS. Conclusion: Although most patients had limited stage, the clinical outcomes of MEITL patients were dismal. While the optimal management of MEITL remains undetermined, achieving CR and consolidative ASCT seem to be essential. In addition, considering the frequent local failure, as well as the CNS relapse, novel therapeutic approaches are required to improve survival. Figure. Figure. Disclosures Kim: Mundipharma: Research Funding; Merck: Research Funding; Celgene: Research Funding; Takeda: Research Funding; Roche: Honoraria, Research Funding; Kyowa-Kirin: Research Funding; Eisai: Honoraria, Research Funding; J&J: Research Funding; Celltrion: Honoraria, Research Funding; Novartis: Research Funding.

Description: Introduction T-cell lymphoma is a group of heterogeneous diseases with various clinical behaviors and treatment outcomes, representing 10-15% of non-Hodgkin lymphomas. Owing to its rarity and heterogeneity, the standard treatment approach for T-cell lymphoma is still not established. Accordingly, conventional chemotherapy regimens adapted from B-cell lymphoma treatment has been used for T-cell lymphoma. However, their outcome is still not satisfactory, and there are limited data representing the real-world situation in terms of clinical features and treatment outcomes. Given the incidence of T-cell lymphoma is relatively higher in Asian than Western countries; a comprehensive registry study focusing on Asian patients with T-cell lymphoma could be helpful for better understanding of T-cell lymphoma as well as the development of more effective treatment strategy. Methods We performed a multi-national, multi-center, prospective registry study for patients with T-cell lymphoma and enrolled patients between 01-March-2016 and 31-January-2019. All patients received chemotherapy with curative intent after diagnosis, and were pathologically diagnosed with T-cell lymphoma according to the 2008 World Health Organization classification of lymphoid neoplasms. Patients belonged to any one of following clinical situations could be enrolled: (1) newly diagnosed, treatment-naïve patients; (2) patients who started treatment or completed treatment; (3) relapsed or refractory patients. After we enrolled the planned number of patients (n = 500), we analyzed clinical features and treatment outcomes. Results Out of 500 patients enrolled from nine Asian countries (Korea, China, Taiwan, Singapore, Indonesia, Bangladeshi, Vietnam, Malaysia, and Philippines), 490 patients were analyzed because 10 patients with insufficient information were excluded. The median age was 59 years (range, 20-85), male patients (59%) were predominant compared to female patients (41%). Extranodal NK/T-cell lymphoma (ENKTL) was the most common (28%) and angioimmunoblastic T-cell lymphoma (AITL) was the second common (24%). Peripheral T-cell lymphoma, not-otherwise specified (PTCL-NOS, 20%) and ALK+/- anaplastic large cell lymphoma (ALCL, 16%) were also major subtypes of T-cell lymphoma. The proportion of stage IV was 40%, however, the distribution of stage was different between ENKTL and nodal T-cell lymphomas such as PTCL-NOS. The CHOP (Cyclophosphamide, doxorubicin, vincristine, and prednisone) or CHOP-like regimens accounted for the mainstay of primary treatment for nodal T-cell lymphoma whereas non-anthracycline-based chemotherapy regimens such as SMILE (steroid, methotrexate, ifosfamide, L-asparaginase, and etoposide) and GemOx-L (gemcitabine, oxaliplatin, and L-asparagainase) were mainly used for ENKTL. The overall survival of ENKTL was not significantly different from that of PTCL-NOS, AITL and ALK+/- ALCL. Conclusions Our study showed the distribution of T-cell lymphoma subtypes and tumor burdens at the time of diagnosis in Asian countries. Although clinical features of ENKTL are different from that of nodal T-cell lymphomas consisting of PTCL-NOS, AITL and ALK+/- ALCL, and the different types of treatment were used, survival outcome of patients were not significantly different. This finding might be associated with improved treatment outcomes of ENKTL compared to the past. However, considering a substantial number of patients experienced treatment failure in patients with PTCL-NOS as well as ENKTL, more effective treatment strategy should be warranted. Figure Disclosures Kim: F. Hoffmann-La Roche Ltd: Research Funding; Celltrion: Research Funding; Novartis: Research Funding; Donga: Research Funding; Kyowa-Kirin: Research Funding; Novartis: Research Funding; J + J: Research Funding.

Description: Abstract 3949 Poster Board III-885 Background Mid-treatment positron emission tomography (PET) has been found to predict clinical outcomes in patients with aggressive non-Hodgkin's lymphoma. Currently, risk-adapted therapy based on mid-treatment PET has been widely evaluated. This study was intended to assess the prognostic value of mid-treatment PET in patients who achieved metabolic complete response (mCR) at post-treatment PET. Methods From February 2002 to March 2009, total 130 patients in whom post-treatment PET showed mCR were included in this study. We performed retrospective analysis of progression-free survival (PFS) and overall survival (OS) according to the results of mid-treatment PET. Results Median age (range) was 51 (16-85) years old, and 70 (54%) patients were male. International Prognostic Index (IPI) was low (0-2) in 91 (70%) patients and high (3-5) in 39 (30%) patients. As a front-line chemotherapy, most frequently administered regimen was R-CHOP (76%). Eighty-seven (67%) patients were mCR, and 43 (33%) patients were metabolic partial response (mPR) in mid-treatment PET. With 24 months of median follow-up, 3 year-rates of PFS and OS in overall patients were 74% and 87%, respectively. Differences of survival outcomes between patients with mCR and mPR at mid-treatment PET were not statistically significant in terms of PFS (p=0.13) and OS (p=0.76). Conclusions In patients with metabolic CR at post-treatment PET, survival outcome was not influenced by the results of mid-treatment PET. Therefore, risk-adapted therapy solely based on mid-treatment PET might be inappropriate in the management of newly diagnosed DLBCL. Disclosures: No relevant conflicts of interest to declare.

Description: Granulocyte colony-stimulating factor (G-CSF) has been given approximately 12 hours before leukapheresis in the patients who are planned to do autologous stem cell collection. The objective of this study was to identify better timing of G-CSF administration which improves the efficacy of autologous stem cell collection. A total of 262 patients (157 male and 105 female patients, ages from 15 to 66 years with median of 49 years) who underwent autologous stem cell collection from January 2000 to March 2008 were included. The patients were diagnosed with Hodgkin’s lymphoma (N=19), non-Hodgkin’s lymphoma (N=131) and multiple myeloma (N=112). Peripheral blood stem cells were mobilized with lenograstim (Choongwae Pharma Corp., Seoul, Korea) following chemotherapy, such as cyclophosphamide (N=141), ESHAP (Etoposide, methylprednisolone, Ara-C and cisplatin, N=73) with (N=14) or without rituximab (N=59) and other chemotherapy regimens (N=48). Before November 2004, patients received lenograstim injection at a dose of 10 μg/kg subcutaneously at 8:00 PM and underwent peripheral stem cell collection on next day (N=129). After then patients received lenograstim injection at 6:00 AM and underwent peripheral stem cell collection at the same day (N=133). Injection of lenograstim at 6 AM was superior to injection of lenograstim at 8 PM with greater numbers of total collected CD34+ cells/kg in shorter duration of leukapheresis procedures (13.29 × 106 versus 8.51 × 106 CD34+ cells/kg; p=0.001, 2 versus 3 leukapheresis procedures; p=0.035). The median number of CD34+ cells/kg collected at first leukapheresis was also greater in 6 AM group (3.94 × 106 versus 2.47 × 106 CD34+ cells/kg; p=0.001). Stem cell collection efficacy defined as ratio of total collected CD34+ cells per days of leukpaheresis were 5.34 and 2.96, respectively. It was significantly better in the group of patients received lenograstim injection at 6 AM (p=0.001). The median number of patients who achieved a total collected CD34+ cells 〉 5 × 106/kg was also greater in 6 AM group (113 versus 96; p=0.002). The present study shows that injection of lenograstim at 6 AM improves the efficacy of stem cell collection with greater number of collected CD34+ cells/kg in shorter duration of leukapheresis procedures compared to that of 8 PM group.

Description: B ackground The advent of new agents has contributed to the prolonged survival of multiple myeloma (MM) patients. From the Durie-Salmon staging system, international staging system (ISS) and recently, revised ISS (R-ISS) have been developed to better prognosticate the survival of MM. R-ISS includes chromosomal abnormalities (CA) detected by interphase fluorescent in situ hybridization (iFISH) and lactate dehydrogenase (LDH) in addition to the ISS. However, the R-ISS has still some limitations in the real clinical settings, as it has enrolled patients exclusively on clinical trials which includes more young patients (age 〈 65 years old), contains non-standardized iFISH results and has short median follow-up duration. The first-line drugs used in the patients could also affect the prognosis. Therefore, a more detailed and standardized but also convenient prognostic system is needed with clinical findings commonly observed in MM patients treated with new agents in the real clinical world. Patient and Method Adult patients who were confirmed multiple myeloma between January, 2011 to December, 2017 and patients who had received thalidomide and/or bortezomib or lenalidomide-based chemotherapy as a first-line treatment were included for the analysis. A total of 861 patients from 13 centers participating Korean multiple myeloma working party were analyzed. Baseline serum albumin, serum ß2-microglobulin, cytogenetics by iFISH, LDH (lactate dehydrogenase), ALC (absolute lymphocyte count), CRP (C-reactive protein) and ferritin were measured within 4 weeks before beginning the first line of chemotherapy. Each factors of age ≥ 65 years, serum ß2-microglobulin ≥ 5.5 mg/L, LDH 〉 normal, cytogenetic high risk by FISH (del17p, t(4;14), t(14;16)), ALC 〈 1500/mm3, CRP ≥ 1.5 mg/dL, and ferritin ≥ 500 ng/mL were defined as abnormal findings, which were given 1 point (Table 1) and the sum of points were used to discriminate inflammatory factor-based staging system (IFBSS). IFBSS were defined as follows: Stage I (point 0), stage II (point 2-3), stage III (point 4-5), and stage IV (point 5-7). Overall survival (OS) was defined by the date of MM diagnosis to the date of death by any cause or follow-up loss. Results Baseline characteristics of the patients were as listed in Table 2. With a median follow-up duration of 22.70 months (range, 0.20-86.80 months), age ≥ 65 years, serum ß2-microglobulin ≥ 5.5 mg/L, LDH 〉 normal, cytogenetic high risk by FISH (del17p, t(4;14), t(14;16)), ALC 〈 1500/mm3, CRP ≥ 1.5 mg/dL, and ferritin ≥ 500 ng/mL showed significant higher OS by univariate and multivariate analysis. Albumin 〈 3.5 mg/dL were excluded into the staging system due the unpredictability to OS in univariate analysis (Table 3). Study groups of inflammatory factor-based scoring system comprised of 61 patients in stage I, 395 patients in stage II, 189 patients in stage III and 36 patients in stage IV. The median OS were not reached in stage I and II, stage III and IV showed a median OS of 36.57 months (95%CI, 33.96-.39.18) and 17.60 months (95%CI, 9.16-.26.04). The OS according to the IFBSS showed significant differences (P 〈 0.001), which predicted OS better compared with conventional ISS and R-ISS (Table 4). Conclusion In the new agent era, inflammatory factors incorporated into the staging system can better discriminate prognosis of multiple myeloma patients compared to the ISS or R-ISS. Validation of this finding in a larger cohort is needed to expand usage of this new staging system. Disclosures Yoon: Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Kyowa Hako Kirin: Research Funding; Janssen: Consultancy; Yuhan Pharma: Research Funding; Genentech, Inc.: Research Funding; MSD: Consultancy.

Description: Abstract 4878 Introduction According to international uniform response criteria for multiple myeloma suggested in 2006, the response assessment for patients with oligo- and non-secretory multiple myeloma (MM) can be evaluated by the serum free light chain (FLC) assay. Although the FLC response criteria are not applicable in MM patients with measurable disease, there were several reports suggesting that serial measurement of serum FLC may detect relapse earlier than protein electrophoresis studies. We, therefore, investigated the preceding changes in serial serum FLC assay until progressive disease was confirmed by the international uniform response criteria in post-ASCT patients with measurable disease. Patients and Method We included patients from the AMC MM transplant registry, who met the following (1) undertook ASCT for measurable disease (2) showed, at least, two serial response assessment of stable disease or complete response before progression or relapse by serum or urine M-protein, (3) had periodic serum FLC assay simultaneously tested with serum and/or urine protein electrophoresis at each response assessment. Progressive disease (PD) was defined by increase of ≥ 25% from baseline in serum M-protein (the absolute increase must be ≥ 0.5mg/dL) and/or urine M-component (the absolute increase must be ' 200mg/24h) according to international uniform response criteria. In this investigation, significant increase in the difference between involved and uninvolved FLC (dFLC) and in the involved FLC (iFLC) was defined by increase of ≥ 25% from baseline. The positive predictive value of three cutoff levels for absolute increase, 10mg/L, 20mg/L, 100mg/L, were evaluated for both dFLC and iFLC provided serum FLC ratio was abnormal. Each patient was followed up with 1-3 month intervals according to the protocol for MM patients after ASCT. Result A total 29 patients of 138 patients in the AMC MM transplant registry satisfied above criteria. When the cut-off level for absolute increase was defined as 100mg/L, the significant increase of iFLC in 12 patients (41%) and dFLC in 11 patients (38%) preceded or accompanied with the time of progressive disease observed by M-protein. The median value of preceding time was 2 month (range -5 - 0). When the cut-off level was defined as 20mg/L, the sustained significant increase of iFLC in 21 patients (72%) and dFLC in 17 patients (59%) preceded or accompanied with the time of progressive disease with median of 2 month (range -9 - 0) and 2 month (range, -5 – 0), respectively. At the cut-off level of 10mg/L, the sustained significant increase of iFLC in 23 patients (79%) and dFLC in 21 patients (72%) preceded or accompanied with the time of progressive disease observed by M-protein. The median of preceding time was 2 month (range -11 - 0) and 1 month (range, -11 - 0), respectively. Twenty-eight dFLC values were observed as negative values out of a total 123 data from 29 patients. Of these values, 12 were below normal iFLC concentration, 14 within normal range of iFLC (kappa 8.5 - 23.7 mg/L, lambda 9.5 - 23.5 mg/L), and 2 above normal iFLC concentration. Conclusion In this study, about 70% of patients showed sustained significant increase of iFLC that preceded or accompanied the time of progressive disease observed by M-protein by a median of 2 months at a cut-off absolute increase of 20mg/L. Although there is a subtle difference in prediction rates according to defined cut-off levels, serial follow up of iFLC and sustained increase by 25% during follow-up seems to have a utility in the prediction of progression after ASCT. In addition, interpretations of dFLC may be difficult as it is frequently observed as negative value in post-ASCT MM patients. Therefore, the serial and sustained increase of iFLC may be useful in lower iFLC concentrations. However, there should be more validation with large patients' population. Disclosures No relevant conflicts of interest to declare.