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Background: Management of CML with TKIs is constrained by treatment resistance, which portends a poor prognosis particularly in pts failing 2 nd-generation TKIs. Cells with BCR-ABL1 T315I mutations are insensitive to 1 st- and 2 nd -generation TKIs, and compound BCR-ABL1 mutations complicate management with all TKIs (including 3 rd-generation ponatinib). Olverembatinib is a novel, potent, 3 rd-generation, orally active BCR-ABL1 TKI with promising activity against CML , largely irrespective of genotype and has a preliminary favorable safety profile. Methods: HQP1351-CC201 and HQP1351-CC202 are Chinese open, single-arm, multicenter phase 2 trials evaluating the safety and efficacy of olverembatinib in adults with TKI-resistant (BCR-ABL1 T351-mutated) CML-CP and CML-CP, respectively. Olverembatinib was administered at 40 mg orally on alternate days for 28-day cycles. The primary outcome measure is major cytogenetic response (MCyR) and major hematologic response (MaHR) by the end of Cycle 12 in CML-CP and CML-AP, respectively. Secondary study endpoints include : complete CyR (CCyR), complete hematologic response (CHR), major molecular response (MMR), progression-free survival (PFS), overall survival (OS), and safety, including treatment-related adverse events (TRAEs) and serious AEs (SAEs). Results: Baseline characteristics Study CC201 （CML-CP ） On the study cutoff date of August 25,2020, 41 pts were enrolled, of whom 32 (78%) completed ≥ 12 cycles and 21 (51.2%) were male. The median (range) follow-up was 13 (3.1-16.3) months, age was 47 (22-70) years, and interval from CML diagnosis to first olverembatinib dose was 5.31 (0.6-23.2) years. In all, 32 (78.1%) pts had received ≥ 2 prior TKIs and 9 pts withdrew because of progressive disease (PD), intolerance, or consent withdrawal before Cycle 12. Study CC202 （CML-AP ） On the cut-off date of July 27, 2020, 23 pts were enrolled, of whom 14 (61%) had completed ≥ 12 cycles and 18 (78.3%) were male. The median (range) follow-up was 13.5 (1.4-15.2) months, age was 41 (21-74) years, and interval from CML diagnosis to first olverembatinib dose was 4.96 (0.4-10.2) years. In all, 18 (78.3%) pts had received ≥ 2 prior TKIs, and 11 pts withdrew because of PD or intolerance before Cycle 12. Efficacy Study CC201 （CML-CP ） After ≥ 12 treatment cycles in pts without responses at baseline, all 31 (100%) experienced CHR (10 other pts had CHR at baseline); 31/41 (75.6%) MCyR; 28/41 (68.3%) CCyR; and 23/41 (56.1%) MMR (Figure 1). The median time to CHR was 1 (95% CI = 1.0-1.9) month, the median time to MCyR was 2.8 (95% CI = 2.8-5.6) months, and the median time to MMR was 6.5 (95% CI = 2.8 to not reached [NR]) months. At 12 months, the PFS rate was 89.3% (95% CI = 73.9%-95.8%), and the OS was 100% (95% CI = 100%-100%). Study CC202 （CML-AP ） After ≥ 12 treatment cycles in pts without responses at baseline, 17/23 (73.9%) experienced MaHR (65.2% CHR and 8.7% no evidence of leukemia [NEL]); 12/23 (52.2%) MCyR; 11/23 (47.8%) CCyR; and 9/23 (39.1%) MMR (Figure 1). The median time to MaHR was 2.8 (95% CI = 1.0-4.7) months, the median time to MCyR was 5.6 (95% CI = 2.00-NR) months, and the median time to MMR was 13.1 (95% CI = 5.6-NR) months. At 12 months, the PFS rate was 74.1% (95% CI = 48.2%-88.4%), and the OS was 91.3% (95% CI = 69.5%-97.8%). Safety Study CC201 （CML-CP ） Frequent TRAEs (all grades; grade 3-4; SAEs) included thrombocytopenia (70.7%; 48.8%; 7.3%), followed by anemia (61%; 26.8%; 2.4%), leukopenia (43.9%; 17.1%; 0), and neutropenia (36.6%; 19.5%; 0). Common nonhematologic TRAEs (all grades; G3-4) included skin pigmentation (56.1%, 0%) and elevations in creatine kinase (51.2%, 14.6%), ALT (39%, 2.4%) and AST (34.1%, 0) (Table 1). No deaths occurred. Study CC202 （CML-AP ） Common TRAEs (all grades; G3-4; SAEs) included thrombocytopenia (73.9%; 56.5%; 17.4%), anemia (60.9%; 34.8%; 13.0%), leukopenia (56.5%; 30.4%; 0), and neutropenia (26.1%; 21.7%; 0). Common nonhematologic AEs included skin pigmentation (69.6%), hypocalcemia (52.2%), proteinuria (47.8%), hypertriglyceridemia (56.5%), hyperphosphatemia (47.8%), hyperuricemia (21.7%), and arthralgia (34.8%), of which most were grade 1-2 (Table 2). Conclusions: Olverembatinib was efficacious and well tolerated when administered as monotherapy in pts with TKI-resistant CP-CML and AP-CML and the BCR-ABL1 T315Imutation. Internal study identifiers: HQP1351-CC201-CC202. ClinicalTrials.gov identifiers: NCT03883087 and NCT03883100. Figure 1 Figure 1. Disclosures Chen: Ascentage Pharma (Suzhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company. Niu: Ascentage Pharma (Suzhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company. Men: Ascentage Pharma (Suzhou) Co., Ltd.: Current Employment, Current equity holder in publicly-traded company. Yang: Ascentage Pharma (Suzhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding. Zhai: Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding; Ascentage Pharma (Suzhou) Co., Ltd.: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding.

Myelofibrosis (MF) is associated with splenomegaly, cytopenias, constitutional symptoms, and bone marrow fibrosis, with limited therapeutic options. Currently only two Janus kinase inhibitors (JAKi) are approved for MF worldwide. Jaktinib, an oral novel JAKi is under investigations. We present the results from a Phase 2 open-label and multi-center study, evaluated two different regimens of Jaktinib in patients (pts) with MF. Aims: To investigate the efficacy, safety and pharmacokinetics (PK) of Jaktinib in MF pts. Methods: Eligibility: MF pts included primary per WHO criteria (2016) or post-essential thrombocythemia / polycythemia vera MF according to IWG-MRT criteria; DIPSS-PLUS ≥ int-2 (int-1 with symptomatic splenomegaly/hepatomegaly required a treatment). From 21 study sites, 104 pts were randomized by 1:1 ratio to Jaktinib 100mg BID or 200mg QD during the first stage, then 14 additional were enrolled to Jaktinib 100mg BID in the second stage, total 118 pts participated in the study. The primary endpoint: the proportion of pts with spleen volume reduction from baseline ≥ 35% (SVR35) at week 24 (W24), assessed by Independent Review Committee based on MRI/CT images. Secondary endpoints: at W24 compared to baseline, the proportion of pts with ≥ 50% reduction on MPN-SAF TSS, improvements in RBC transfusion and hemoglobin (Hgb), safety profiles as well as the PK characteristics, etc. Results: 118 pts who completed treatments of 24 weeks or planned visits were summarized. Baseline characteristics were generally balanced between the two groups, and shown in Table 1. At W24, the SVR35 were 51.5% (34/66) in the 100mg BID and 28.8% (15/52) in the 200mg QD (p=0.0151), the median duration of response has not reached yet for the 100mg BID and 11.0 months for the 200mg QD. The median time to achieve a first SVR35 was 5.5 months and 11.0months, respectively. The proportion of pts achieved ≥50% improvement in TSS at W24 from baseline for BID and QD arms were 63.6% (42/66) and 53.8% (28/52), respectively. The mean percent of TSS change from baseline was -62.00 and -42.01, respectively. Approximately 35.6% (21 /59) of combined 59 pts whose baseline's Hgb ≤100g/L had elevated ≥20g/L at W24. Of the 6 pts who were transfusion-dependent at baseline, 2 pts became transfusion-independent after treatment. In addition, 5 (71.4%) out of 7 pts had a RBC infusion decreased ≥50%. The most common Grade ≥3 hematological TEAEs (≥ 5%) were anemia (100mg BID 24.2%, 200mg QD 28.8%), thrombocytopenia (16.7%, 11.5%), neutropenia (3.0%, 11.5%), and leukopenia (0, 7.7%). Most common non-hematological (of any grade) TEAEs (≥10%) were upper respiratory tract infection (24.2%, 30.8%), elevated creatinine (19.7%, 30.8%), elevated ALT (24.2%, 21.2%) and elevated bilirubin (24.2%, 13.5%), predominantly in Grade 1 or 2. A total 64 (54.2%) of the combined 118 pts had ≥ 1 dose adjustment/interruption, mostly due to thrombocytopenia (31.4%), anemia (22.0%), and neutropenia (8.5%), while 10 (10.2%) pts discontinued the treatment because of adverse events (thrombocytopenia[n=3], anemia[n=2，with 1 pts occurring pneumonia at the same time], pneumonia[n=1], tuberculosis[n=2], upper gastrointestinal bleeding[n=1], chronic kidney disease[n=1]). Total 23 (100mg BID 12 and 200mg QD 11) pts had their blood PK samples collected per protocol schedule. After single oral administration, the median T max is 2h and the average t 1/2 is 3~4 h in both groups. The AUC 0-24 of Jaktinib and its metabolites on the first day were comparable in both groups. After multiple doses, in comparison to 200mg QD, 100mg BID had a decreased C max and an increased C trough, resulting in less fluctuation between the peak and trough concentrations, which indicated that continual inhibitions of JAK-STAT pathway may result in better clinical outcomes. Summary/Conclusion: Jaktinib as a novel JAKi is generally well-tolerated and safe in Chinese MF pts. Significant reductions in spleen volume and constitutional symptom burden were observed in the 100mg BID, and also a sign of improvement was shown in RBC transfusion dependency and Hgb levels after Jaktinib treatment. Follow-up study is on-going and will provide long-term efficacy and safety data of Jaktinib. Figure 1 Figure 1. Disclosures Zhou: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Jiang: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Wu: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Zhuang: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Li: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Wang: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Huang: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Zhu: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Zhang: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Du: Suzhou Zelgen Biopharmaceuticals Co.,Ltd.: Honoraria. Xiang: I agree not to accept honoraria or reimbursement, including travel support, from ineligible companies for my role as a chair/moderator/presenter in the accredited portions of this activity: Honoraria. Zhang: The content I am responsible for will be free of logos or other corporate identifiers of healthcare industry companies, specifically those whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or : Honoraria. Hu: Astellas Pharma, Inc.: Research Funding. Liu: The content I am responsible for will be free of logos or other corporate identifiers of healthcare industry companies, specifically those whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or : Honoraria. Jin: The content I am responsible for will be free of logos or other corporate identifiers of healthcare industry companies, specifically those whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or : Honoraria. Sun: The content I am responsible for will be free of logos or other corporate identifiers of healthcare industry companies, specifically those whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or : Honoraria. Zhou: The content I am responsible for will be free of logos or other corporate identifiers of healthcare industry companies, specifically those whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or : Honoraria.

INTRODUCTION HQP1351 (olverembatinib) is an orally active third-generation BCR-ABL TKI designed for treatment of the patients with CML, harboring T315I mutation, which confers resistance against all first- and second-generation TKIs. METHODS The TKI resistant CML patients harboring T315I mutations either in chronic-phase (CP), or in accelerated-phase (AP), were enrolled into two single-arm, multicenter, open-label pivotal studies: HQP1351-CC201 in and HQP1351-CC202, respectively. The HQP1351 was administered at 40 mg once every other day (QOD) for 28 consecutive days per cycle over 24 months. The primary objective was to evaluate efficacy by major cytogenetic response (MCyR) in patients with CML-CP and major hematologic response (MaHR) in CML-AP. Secondary objectives included safety, tolerability, and pharmacokinetics (PK). RESULTS Baseline characteristics Study CC201 (CML-CP) As of the study cut-off date of March 23, 2020, total 41 patients were enrolled, of whom 38 (92.7%) completed ≥ 6 cycles and 21 (51.2%) were male. Median (range) follow-up was 7.9 (3.1-11.1) months, median age was 47 (22-70) years old. Median (range) interval from CML diagnosis to first HQP1351 treatment was 5.31 (0.6-23.2) years, and 32 (78.1%) patients received ≥ 2 prior lines of TKI. Three patients withdrew from the study-due to progressive disease (PD), intolerance, or consent withdrawal. Study CC202 (CML-AP) As of the cut-off date of February 11, 2020, total 23 patients were enrolled, of whom 18 (78.3%) completed ≥ 6 cycles and 18 (78.3%) were male. Follow-up duration was 8.2 (1.4-9.6) months, median age was 41 (21-74) years old. Median interval from CML diagnosis to first dose of HQP1351 was 4.96 (0.4-10.2) years, and 18 (78.3%) patients received ≥ 2 prior TKIs. Five patients withdrew because of PD or intolerance before Cycle 6. Efficacy Study CC201 (CML-CP) Across a median follow-up of 7.9 months, the mean (95% CI) 3-month progression-free survival (PFS) was 100% (100-100%) and 6-month PFS 96.7% (78.6-99.5%) because of 1 PD. In 31 evaluable patients who did not have a complete hematologic response (CHR) at baseline, 30 (96.8%) achieved CHR. In 41 evaluable patients who did not have a complete CyR (CCyR) at baseline, 31 (75.6%) achieved MCyR, including 27 (65.9%) CCyR and 4 (9.8%) partial CyR (PCyR). Total 20 out of 41 (48.8%) evaluable patients achieved major molecular response (MMR; Figure 1). Study CC202 (CML-AP) Across a median follow-up of 8.2 months, the 3-month PFS was 100% (100-100%) and the 6- month PFS 95.5% (71.9-99.3%) because of 2 PDs. A total of 18 (78.3%) of 23 evaluable patients without MaHR at baseline achieved MaHR, including 14 (60.9%) with CHR. In the 23 evaluable patients without MCyR at baseline, 12 (52.2%) patients achieved MCyR, including 9 (39.1%) CCyR and 3 (13.1%) PCyR. A total of 6 out of 23 (26.1%) evaluable patients achieved MMR (Figure 1). HQP1351 was highly and durably efficacious in the CML patients with T315I mutation; the probability and depth of clinical response may increase with prolonged treatment period. Safety/tolerability Study CC201 Frequent treatment-related adverse events (TRAEs; all grades; G3-4) included thrombocytopenia (65.9%; 48.8%), followed by anemia (48.8%; 24.4%), leukopenia (46.3%; 12.2%), and neutropenia (36.6%; 19.5%). Common non-hematologic TRAEs of any grade included skin pigmentation (53.7%) as well as elevations in creatine kinase (48.8%), ALT (31.7%) and AST (26.8% which most were grade 1 - 2. No death occurred. Study CC202 Common TRAEs (all grades; G3-4; serious AE [SAE]) included thrombocytopenia (73.9%; 52.2%; 17.4%), anemia (65.2%; 39.1%; 13.0%), leukopenia (56.5%; 30.4%; 0%), and neutropenia (26.1%; 21.7%; 0%;). Common non-hematologic AEs included skin pigmentation (69.6%), hypocalcemia (52.2%), proteinuria (52.2%), hypertriglyceridemia (47.8%), hyperphosphatemia (43.5%), arthralgia (34.8%), and fatigue (26.1%), of which most were grade 1- 2. CONCLUSIONS HQP1351 has been shown highly efficacious in heavily TKI-pretreated patients with T315I-mutated CML-CP or CML-AP and was well tolerated. Registration: Clinicaltrials.gov identifier NCT03883087 (Study HQP1351-CC201) NCT03883100 (Study HQP1351-CC202). Disclosures Chen: Ascentage Pharma Group: Current Employment. Niu:Ascentage Pharma Group: Current Employment. Zeng:Ascentage Pharma Group: Current Employment. Men:Ascentage Pharma Group: Current Employment. Lu:Ascentage Pharma Group: Current Employment, Current equity holder in publicly-traded company. Wang:Ascentage Pharma Group: Current Employment. JI:Ascentage Pharma Group: Current Employment. Yue:Ascentage Pharma Group: Current Employment. Yang:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests. Zhai:Ascentage Pharma (SuZhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests.

Background: Ruxolitinib, a potent JAK1/JAK2 inhibitor, has been proved to improved splenomegaly and debilitating myelofibrosis-related symptoms in several clinical trials. However, not much is known about the efficacy of ruxolitinib, especially low-dose ruxolitinib, in real world patients in China. Here we assess the efficacy of ruxolitinib in treatment of patients with myeloproliferative neoplasms associated myelofibrosis (MPN-MF) in real world and to analyze factors affect the treatment efficacy. Methods and Results: From July 2017 to June 2019, data of MPN-MF patients treated with ruxolitinib in West China hospital, Sichuan University, China, were retrospectively collected and analyzed. Logistic regression was used for univariate and multivariate analysis of binary variables. Simple linear regression was used in univariate analysis of continuous variables, and multiple linear regression was used in multivariate analysis of continuous variables. Dose of ruxolitinib were decided according to platelet count and financial condition of patients. Of 72 MPN-MF patients, 1 patient was treated with ruxolitinib in an initial dose of 5mg qd, 37 patients with 5mg bid, 15 patients with 10mg bid, 2 patients with 25mg bid. At week 12, 89.3% of patients achieved reduction from baseline in palpable spleen length, of which 44.6% patients achieved ≥50% reduction (Figure 1) ; 95.6% patients achieved reduction from baseline in Total Symptom Score (TSS), of which 44.6% patients achieved ≥50% reduction(Figure 2). At week 48, all 25 patients with bone marrow biopsies achieved improved or stable bone marrow fibrosis grading from baseline, of which 44.0% improved (Figure 3). Both univariate analysis and multivariate analyses showed higher dose of ruxolitinib (>5mg bid VS ≤5mg bid and>10mg bid VS ≤10mg bid) was the major factor associated with better spleen response(P10mg VS ≤10mg) was the only factor associated with better TSS improvement(P Conclusion These data indicated that ruxolitinib treatment provided reduction in spleen, improvement in symptoms and stable or improve bone marrow fibrosis in Chinese MPN-MF patients. Although some MPN-MF patients derived benefit at low-dose ruxolitinib, higher dose were associated with better spleen and symptom responses. Legends to figures Figure 1: Percent change from baseline in palpable spleen length at week 12 for individual patients. Only patients with palpable spleen length measurements at baseline and week 12 (n=56) were included. qd: once daily, bid: twice daily Figure 2: Percent change from baseline in TSS at week 12 for individual patients. Only patients with TSS measurements at baseline and week 12 (n=68) were included. qd: once daily, bid: twice daily Figure 3: Change in marrow histomorphologic features in 25 patients at week 48. Green: fibrosis improved, Yellow: fibrosis stable, Red: fibrosis progress Disclosures No relevant conflicts of interest to declare.

Background: Mutations of FMS-like tyrosine kinase 3 (FLT3) in acute myeloid leukemia (AML) are associated with poor prognosis. SKLB1028, a novel multikinase inhibitor, has shown exceptional antileukemic activity in mouse xenograft models of FLT3-driven AML. Preclinical data has demonstrated that SKLB1028 has anti-proliferation and pro-apoptosis effects on tumor cells in vitro and in vivo, and prolonged survival in SKLB1028-treated mice has been observed in a dose-dependent manner (Cao et al., Leukemia, 2012). The present study is to assess the safety, tolerability and pharmacokinetics (PK) of SKLB1028 in patients with relapsed/refractory (R/R) FLT3-mutated AML. Here we report the preliminary analysis results of the study. Methods: An open label, 3+3 cohort dose escalation, single arm, phase I study was conducted in adult patients with FLT3-mutated AML who were refractory to or relapsed after ≥ 1 cycle of induction chemotherapy and had an Eastern Cooperative Oncology Group performance status of ≤ 3. Dose cohorts of at least 3 patients received study drug following a sequential dose-escalation design with 20 mg/day as the lowest dose level. For each dose level, patients were firstly given 1 dose of SKLB1028 as an oral capsule followed by 72-hour observation in the single-dose PK period. Then the patients entered the repeated-dose period from day 1, cycle 1, and received oral SKLB1028 once per day in a 28-day cycle. Observations of dose limiting toxicities (DLTs) were recorded through cycle 1. For a specific dose level, if a DLT was observed during the first cycle in 1 patient, 3 additional patients were enrolled at that level. If a second DLT was observed within the same dose cohort, escalation was discontinued, and maximum tolerated dose (MTD) was defined as the immediately lower dose level. Patient who had completed cycle 1 and did not experience a DLT or disease progressionduring cycle 1 could continue receiving SKLB1028, at the discretion of the investigator, until disease progression or intolerable toxicity occurred. The primary endpoints were safety and tolerability. Secondary endpoints included PK and efficacy. Analyses of safety (e.g. DLT and adverse event (AE)) and efficacy parameters (e.g. complete response (CR) and partial response (PR))were performed using descriptive statistics on safety analysis set and full analysis set respectively. PK parameters were estimated using non-compartmental analysis on PK analysis set. Results: Twenty-eight patients with a median age of 50 years (range 19-70 years) were enrolled. The median number of prior regimens was 3.5 (range 1-9). Patients received a median of 2.5 cycles (range 1-15)of therapyin 8 dose cohorts: 20, 40, 80, 120, 160, 200, 250, and 310 mg/day. Three patients discontinued from the study due to AEs. For a subject to be eligible for DLT evaluation, he/she should have received 100% of the planned (28) doses of SKLB1028 in cycle 1, unless the doses were omitted for DLT defining event. Two patients did not complete the first treatment cycle, 1 because of DLT and 1 because of withdrawal of consent. Twenty-seven patients were evaluable for DLT.One patient in the 200 mg cohort experienced DLT (Grade 3 hepatic function abnormal). Among 3 additional patients at this dose level, no DLTs occurred again. The most common treatment-emergent AEs of any grade (regardless of causality) were pyrexia (67.9%), diarrhoea (64.3%), asthenia (53.6%), dizziness (50.0%). There was no death attributed to the use of SKLB1028. The MTD had not been reached. Among the 28 patients treated, only 26 patients were evaluable for efficacy. Two patients were not enlisted due to premature discontinuation of study drug in cycle 1; 1 for DLT and the other for withdrawal of consent. Of 28 patients in the full analysis set, overall response rate (ORR) was 21.4% (6/28) with 1 CR, 5 PR, 20 stable disease and no progressive disease as the best response. One patient achieved CR at the does of 250 mg/day. Of the 5 patients with PR, 1 was in the 160mg cohort, 3 in the 200 mg cohort, and 1 in the 310 mg cohort. The ORR for the 160 mg, 200 mg, 250 mg, and 310 mg cohort of 16 patients was 37.5% (6/16). Conclusions: The results of our preliminary analysis suggested that SKLB1028 is safe, well-tolerated and effective for R/R FLT3-mutated AML patients. Larger studies are needed to more comprehensively assess the safety and efficacy of SKLB1028 in this population. This trial is registered at Clinical Trials.gov, number NCT02859948. Disclosures Yao: CSPC Zhongqi: Employment. Wang:CSPC Zhongqi: Employment. Zhan:CSPC Zhongqi: Employment. Ni:CSPC Zhongqi: Employment. Qiao:CSPC Zhongqi: Employment. Hu:CSPC Zhongqi: Employment.

Introduction: Treatment with dasatinib, a second-generation tyrosine kinase inhibitor (TKI), has resulted in high rates of cytogenetic and molecular responses for pts with CML-CP, both as initial therapy and after failure of other therapies. A reduction in BCR-ABL1 transcript levels to ≤ 10% on the International Scale (IS) at 3 mo is associated with an improved probability of deep molecular responses and superior progression-free and overall survival (PFS and OS). In DASISION, considerably more pts treated with dasatinib achieved BCR-ABL1 ≤ 10% IS compared to imatinib. BCR-ABL1 ≤ 10% IS at 3 mo is considered an optimal response by international guidelines; however, approximately one-third of pts with CML-CP on first-line (1L) imatinib will not achieve this threshold. Clinical studies exploring the potential benefit of early switching to dasatinib in pts with less than optimal responses on initial imatinib treatment have not been reported. Methods: DASCERN (NCT01593254) is a randomized, open-label, international phase 2b trial in adult pts with CML-CP who had achieved complete hematologic response (CHR) but who had BCR-ABL1 > 10% IS at 3 mo after initial treatment with 400 mg imatinib once daily (QD). Imatinib must have been started within 6 mo of the initial CML-CP diagnosis. Pts were randomized 2:1 to receive 100 mg dasatinib QD or continue imatinib at ≥ 400 mg daily with the option for dose escalation. Pts initially randomized in the imatinib cohort who met European LeukemiaNet 2013 failure criteria after randomization and without dasatinib-resistant mutations were crossed over to the dasatinib arm. The primary endpoint in DASCERN is the rate of MMR (BCR-ABL1 < 0.1% IS) at 12 mo after day 1 initiation of 1L imatinib (9 mo after randomization). Secondary endpoints include time to MMR, OS, and PFS (progression was defined as transformation to accelerated/blast phase or death). Tertiary endpoints include safety and tolerability profile of both treatment arms and cytogenetic response over time. Results: All 260 randomized pts (dasatinib: n = 174; imatinib: n = 86) had a minimum follow-up of ≥ 12 mo from the last pts 1st visit (Sokal scores: 28% low, 30% intermediate, 24% high, 18% unknown; median age 37 y [range 18-82, 95% were < 65 y]; 78% male; 73% Asian). All pts had e13a2 or e14a2 transcript types. At the time of analysis, 84% of pts were continuing in the study. Median daily dose was 100 mg QD (range 26-142) for dasatinib and 400 mg QD (range 129-825) for imatinib. Median treatment duration was 111 wk (774 d) in the dasatinib arm and 68 wk (477 d) in the imatinib arm; 42 (49%) imatinib-randomized pts crossed over to dasatinib. Rate of MMR at 12 mo in the intent-to-treat population was 29% (95% confidence interval [CI] 22, 36) for dasatinib and 13% (95% CI 7, 22) for imatinib (P = 0.005); median time to MMR was 14 mo (range 12-18) for dasatinib vs 20 mo (range 14-26) for imatinib (P = 0.053). No differences in the rate of progression or OS were observed between treatment arms. No new safety signals were observed for either treatment arm and the early switch to dasatinib did not increase the toxicity rate. Treatment-emergent pleural effusion (PE; any grade) occurred in 11 (6%) pts randomized to dasatinib and 3 (7%) imatinib-randomized pts who crossed over to dasatinib; treatment-emergent PE grade 3/4 occurred in 1 (1%) pt randomized to dasatinib and 2 (5%) pts randomized to imatinib who crossed over to dasatinib. Hematologic toxicity was similar between treatment arms: neutropenia grade 3/4 occurred in 18 (11%) pts randomized to dasatinib and 12 (29%) pts randomized to imatinib who crossed over to dasatinib; thrombocytopenia grade 3/4 occurred in 18 (11%) pts randomized to dasatinib and in 7 (17%) pts randomized to imatinib who crossed over to dasatinib. Two dasatinib-treated pts discontinued due to hematologic toxicity (1 neutropenia, 1 thrombocytopenia). Conclusions: Early results from DASCERN show that pts with suboptimal responses to imatinib at 3 mo who switched to dasatinib had a significantly increased rate of MMR at 12 mo compared to pts who remained on imatinib. Longer follow-up is required to assess the impact of early switching on PFS and OS, and achievement of deep molecular responses. Disclosures Cortes: Astellas Pharma: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Arog: Research Funding. Hochhaus:Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Novartis: Research Funding; Incyte: Research Funding; Takeda: Research Funding. Kim:BMS: Research Funding; Ilyang: Research Funding; Pfizer: Research Funding; Novartis: Research Funding. Savona:Boehringer Ingelheim: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding. Martin Regueira:Bristol-Myers Squibb: Employment, Equity Ownership. Sy:Bristol-Myers Squibb: Employment. Gurnani:Bristol-Myers Squibb: Employment.

Objective. Hemophagocytic lymphohistiocytosis (HLH), also known as Hemophagocytic Syndrome (HPS), is an increasingly recognized clinical syndrome that is characterized by extreme immune activation. HLH was first described as an inherited immune disorder in pediatrics, but it may also arise in adults as the result of persistent antigen stimulation due to infections, autoimmune disorders or malignancies. Early recognition of HLH and appropriate treatment are critically important. For the pediatric patients, the Histiocyte Society Study Group for HLH has developed the HLH-94 and HLH-2004 treatment protocols, but there is no such guideline or consensus for adult HLH. Although there were increasing amount of clinical studies in adult HLH, the majority of them just described the etiologies and clinical profiles, and failed to analyze the treatment effects on outcomes. Therefore, there is an urgent need for more clinical data focusing on treatment in adult HLH patients, in order to clarify optimal therapeutic regimens. Our study retrospectively analyzed the causes, treatment strategies, and relevant outcomes in 104 adult HLH patients in our institution, and with the goal of identifying more appropriate therapeutic strategies for adult HLH patients. Methods. After the approval of our protocol by local institutional Ethics Committee, the medical records of 104 consecutive patients with adult onset HLH in West China Hospital from June 2008 to February 2016 were reviewed. The diagnosis was re-confirmed according to HLH-04 criteria, and demographic data, clinical profiles, treatments and outcomes were collected and analyzed. The latest follow-up visit occurred on 1st July 2016. The different therapeutic effects on prognosis were discussed based on the endpoints which were defined as short-term (30 days) and long-term (last follow-up date) survival rates. Statistical analysis was performed on SAS 9.4 software, and was involved in Log-rank test in univariate analysis and Cox proportional hazard regression model in multivariate analysis. All p values were two-sided and p Results. All of 104 consecutive patients with adult HLH were enrolled in this study. The male/female ratio was 1.6:1 with the median age of 35 (range 16-77). In etiological classification, 75 cases were lymphoma-associated HLH, 13 cases were infection-associated HLH, 2 cases were with autoimmune disorders, and for the remaining 14 cases, the underlying diseases could not be identified. In treatment analysis, corticosteroids were used in 91 cases (87.5%), the median initiation time was 0 day (range 0-26 days) after HLH diagnosis, the median four-week accumulating dosage was 236.57mg dexamethasone. Etoposide was employed in 55 cases (52.9%), the median initiation time was 3.5 days (range 0-62 days), the median four-week accumulating dosage was 590.00mg. Cyclosporine A (CSA) was used in 42 cases (40.4%), the median initiation time was 2 days (range 0-51 days), the median four-week accumulating dosage was 7100.00mg. The median survival time for all patients was 46 days (1-2529 days). On the 30th day after admission, 27 patients (26.0%) had died, and 77 patients (74.0%) had survived. At the last follow-up visit, 74 patients (71.2%) had died, 17 patients (16.2%) were still alive, and 13 patients had been lost to follow-up. Statistical analysis indicated that patients in etoposide-treated group was associated with superior short-term survival rate, compared with non-etoposide-treated group (p=0.0471), but there was no difference in long-term survival rate between the two groups. CSA-treated group was associated with inferior long-term survival rate (p=0.0214), compared with non-CSA-treated group. In patients with lymphoma-associated HLH, those who received antineoplastic chemotherapy had a higher long-term survival rate than those who did not receive it (HAZARD=0.07, p Conclusion. The major underlying diseases of adult onset HLH are malignant lymphomas. Etoposide might only improve the short-term survival, but fail to change the long-term survival. Immunosuppressor CSA seems to be associated with negative effects on long-term survival rate. For patients with lymphoma-associated HLH, antineoplastic chemotherapy might improve the long-term outcome. More clinical prospective studies should be initiated for adult acquired HLH. Disclosures No relevant conflicts of interest to declare.

Background In China, the incidence of aplastic anemia (AA) is about 0.74/105, with 0.14/105 of severe aplastic anemia (SAA). Most of these SAA patients are treated in big medical centers or traditional Chinese medicine (TCM) hospitals, which could stand for the current practices in China. Despite the China Aplastic Anemia Consensus, published in 2010, recommended that the immunosuppressive therapy (IST) and hematopoietic stem cell transplantation (HSCT) were the standard treatment for SAA, very severe aplastic anemia (VSAA) and transfusion-dependent non-severe aplastic anemia (TD-NSAA), the current treatment options for patients with these diseases are diverse, including antithymocyte globulin (ATG)/antilymphocyte globulin (ALG) + cyclosporin A (CsA), CSA + androgen, CSA or androgen alone, only supportive care, TCM, etc. This national disease registry study aimed to describe the current clinical practice and treatment patterns for SAA, VSAA and TD-NSAA patients in China and understand their IST patterns as well as the supportive care measures. Methods In this prospective, multi-center, observational study, adult or pediatric patients diagnosed as acquired aplastic anemia within 3 months and met the guideline criteria of SAA, VSAA or TD-NSAA were enrolled from October 2012 to April 2014. All enrolled patients will be followed at least for one year. Each subject will be visited every 3 months in the first year and every 6 months from the second year until the patients withdraw the ICF or study close. The main evaluation criteria is the treatment patterns of SAA, VSAA and TD-NSAA which will be specified as: IST (ATG + CsA, CsA + androgen, CsA and others), HSCT, TCM, androgen, supportive care and others. The response of SAA/VSAA and TD-NSAA after each treatment, and serious adverse events, will also be evaluated by the investigators. An interim analysis is planned when all patients have been enrolled (target N=350) and will focus on their baseline characteristics and first treatment choice. This study was sponsored by Sanofi. Results A total of 352 patients were enrolled at 29 sites in China (SAA 221 pts; VSAA 84 pts; TD-NSAA 47 pts). The median age was 21 years (range, 0-84) and 65.1% were adults. 51.7% were male and 71.6% had ECOG PS Conclusions Chinese AA patients received diverse treatments in real life clinical practice. Based on this interim analysis, 74.1% of the SAA, VSAA and TD-NSAA patients in China received IST. But only 26.4% of them received the standard ATG + CsA therapy. TCM therapy still played a role in the treatment, especially for SAA and VSAA patients in China. Final results including efficacy and safety profiles will be reported later. Disclosures Off Label Use: Anti-thymocyte globulin-Fresenius is used as an immunosuppressive therapy for the treatment of aplastic anemia.

Abstract 3714 Background: The non-GCB subtype of diffuse large B-cell lymphoma(DLBCL) has inferior response to rituximab based chemothrapy. Recent reports show a constitutional expression of NF-κB pathway in non-GCB subtype of DLBCL. Bortezomib, as proteasome inhibitor, has been shown a promising new agent for the treatment of DLBCL. As how the efficacy, doses and protocol of Bortezomib need to be clarified. Objective: This trial is a pilot multicenter clinical study to evaluate the efficacy and safety of an escalated dose of bortezomib based chemotherapy for the treatment of patients with relapsed or refractory non-GCB subtype of DLBCL. Patients and Materials: A total 24 pts with DLBCL were enrolled in 4 different medical centers. According to Hans' Tissue Microarray (TMA) Classification, 23 pts were diagnosed as non-GCB subtype, and 1 patient have not done the test. 16 pts had relapsed or refractory disease, while 8 pts had fail response to the first line treatment. All the patients had received Rituximab based chemotherapy previously. There were 16 male and 8 female. The patient age ranged from 19 to 73, of which the median age was 55. Methods: All patients were given bortezomib 2.0mg/m2, day 1, I.V. (intravenous injection 12 hours before chemotherapy), 5 pts were given additional dose of 0.7 mg/m2, I.V., at day 8. The combination protocols include: Bortezomib(V)+ICE(G) 13 pts; Bortezomib(V)+HyperCVAD 7 pts; Bortezomib(V)+EPOCH 3 pts; Bortezomib(V)+DHAP 1 pts. The patients were given 1 to 5.courses differently. Results: The follow-up time were 2 to18 months, with a median time of 8 months. Of 24 pts, 21 evaluable pts received more than 2 courses of therapy: 7 pts achieved complete remission (CR 33.3%), 9 pts achieved partial remission (PR 42.8%), 5 pts had no response (NR 23.8%), The overall response rate (ORR) was 76.1%. Of 16 responsive pts, the PFS were 2 to 18 months; the average PFS was 7.6 months and median PFS was 7.5 months. Up to now, 13 pts were still alive, and 7 pts were dead, and 1 pts lost follow-up. Of 7 death, 5 were caused by disease progression with 4 pts of central nervous infiltrates, 2 were caused by severe infections. The one year overall survival rate (OS) was 65%. Of all the 24 pts, 10 pts had 3 to 4 grade of myelosuppression; 1 case with severe pulmonary infection;1 case with septicemia; 1 case with skin and soft tissue infection; 1 case with fungus infection; 3 cases with herpes zoster infection; 2 cases with skin rashes; 2 cases with hypotension, 1 case with hepatic dysfunction; 1 case with neuralgia. Conclusion: Our study showed that the escalated dose of bortezomib based chemotherapy had promising response for the treatment of relapsed or refractory non-GCB originated DLBCL. Bortezomib at a single dose of 2.0mg/m2 was safe and tolerable. No acute toxicity or vital adverse events were observed. The relapse of disease in central nervous system as well as infections were relatively common and might need further study. Disclosures: No relevant conflicts of interest to declare.

Abstract 4243 [Background] Imatinib combined with intensive chemotherapy protocol markedly has markedly improved the prognosis of patients with Philadelphia chromosome-positive acute lymphocytic leukemia (Ph+ALL), and has become the standard therapy for this disease. Based on experience from patients with chronic myelogenous leukemia in blast crisis or accelerated phase, this highly specific tyrosine kinase inhibitor was given 600mg or 800mg daily in most clinical trials. However, some pilot study and case report implied that either lower dose of imatinib or less intensive chemotherapy could also achieve a satisfying remission rate. We carried out this pilot study to testify whether a lower dose of imatinib and less intensive chemotherapy could generate similar outcome, especially for patient who are unwilling to or unsuitable for allogeneic hematopoietic stem cell transplantation. [Method] Thirty six patients with de novo Ph+ALL were enrolled between Dec-2008 and Dec-2010. All patients received imatinib 400mg daily, vindesine 4 mg weekly and dexamethasone 10 mg/m2/day for 4 days per week as induction therapy. After complete remission, these patients received 3 courses chemotherapy of protocols adapted from China Acute Lymphocytic Leukemia Group (CALLG) as intensification. Those who were unwilling to receive or unsuitable for allo-HSCT received maintenance therapy with imatinib 400mg daily with chemotherapy by vindesine 4 mg on D1 and D11, dexamethasone 10mg/m2/day on D1-5 and D11-15 with or without interferon-α 3 million unit every other day. Patients over 55 year old skipped the intensification therapy. The maintenance chemotherapy was given once a month in the first year, once per 2 months in the second year, and once per 3 months in the third year. Sixteen cycles of intrathecal chemotherapy with cytarabine and dexamethasone +/− methotrexate was scheduled for central nervous system leukemia (CNSL) prophylaxis. [Result] Thirty six patients were enrolled, and the median age of this group of patients was 33.5 years (shown in table 1). All but one patients (97.2%) achieved complete remission after 4 weeks of induction therapy. One patient was loss of follow-up and one patient quit from this study because of severe hepatic dysfunction thought to be caused by imatinib. Three patients (8.3%) died of infections (pneumonia or sepsis) within intensification cycles. Three (8.3%) patients received allo-HSCT either from a sibling or an unrelated donor at CR1 after 3–4 courses of intensification therapy. The median time of follow-up was 8 months. The median overall survival was were 22.1 (shown in figure 1A.). For patients who received imatinib and chemotherapy only, the median overall survival was 20.4 months (shown in figure 1B). Although there was no evidence for CNSL at diagnosis in all patient, four (11.1%) patients had CNS relapse and three died despite of regular CNSL prophylaxis. [Conclusion] In this pilot study, our data showed that imatinib combined with less intensive chemotherapy could also achieve a over 90% remission rate in patients with de novo Ph+ALL. With the short time of follow-up, the long term effect of this strategy on survival and relapse can not determined yet, and a prospective randomized study is warranted. With reduced chemotherapy intensity, a more intensive protocol for CNS prophylaxis or new generation of TKI (e.g. dasatinib) with higher blood-brain barrier permeability may be considered. Disclosures: No relevant conflicts of interest to declare.

Abstract 1117 Poster Board I-139 Objective The human organic cation transporter-1(hOCT-1) is the major active influx protein responsible for the transport of imatinib into cells. The functional activity of the hOCT-1 protein using 14-C detected by others demonstrated a link between CML molecular response and hOCT-1 activity. However, 14-C labeled detection is not convenient in routine clinical practice. Hence, we use flow cytometry to detect hOCT-1 protein expression level in CML patient and try to find some relation between hOCT-1 expression and imatinib response. Subjects and methods In this study, 64 CML CP patients and 31 healthy donors were enrolled. Totally, there are 78 patient' peripheral blood (PB) or bone marrow (BM) samples and 31 donor PB samples were measured. The hOCT-1 protein expression levels were detected by indirect immunofluorescent flow cytometry. The hOCT-1 levels were expressed as mean fluorescent intensity (MFI). In avoided to systematic error, lymphocytes which had little hOCT-1 expression were used as internal negative control. Results ‡@ Assessing PB hOCT-1 expressing in patients with donors, hOCT-1 level is higher in healthy donors than in CML patient (mean±standard deviation 9.11±6.04,5.60±3.74,P=0.005). ‡AThe hOCT-1 level was compared with molecular response in patients. Of 39 patients achieved optimal molecular response, the hOCT-1 level was 6.49±3.83, versus 3.86±2.91 in 20 patients with non-optimal response(P=0.009). Comparing 39 optimal responders with 16 sub-optimal responders, hOCT-1 level were 6.49±3.83, versus 3.98±1.23(P=0.025. ‡B Assessing CML stages with hOCT-1 expression, there is no significant difference in chronic stage and advanced stage(5.93±3.87, 3.49±1.64, P=0.085). Conclusions hOCT-1 expression level measured by flow cytometry is very convenient and clinically available. The hOCT-1 expression level can be an important predictor in CML patients treated with imatinib mesylate. Disclosures No relevant conflicts of interest to declare.

Objective: To evaluate effect of human organic cation transporter 1((hOCT1) polymorphism on Imatinib Mesylate (IM) in Chinese CML patients. Material and Methods: Totally 76 patients were enrolled(53 CML, 23 non-CML patients). The 53 CML patients were categorized as optimal-, suboptimal-and failure ones, according to their clinical response. 2 Tibetan nationality Chinese patients were described separately. In this study, amplification refractory mutation system (ARMS)-polymerase chain reaction was used to amplify the polymorphism gene segment of hOCT1- P283L, R287G, M408V. Results: In the 74 Chinese Han subjects: ‡@ The frequencies of CC ACT ATT genotype in hOCT1- P283L were 35.14%,50.00%,14.86%; the allele C AT frequencies were 60.14% and 39.86%, respectively; ‡A The frequencies of CC ACG AGG genotype in hOCT1- R287G were 51.35%,39.19%,9.46% Gthe allele C AG frequencies were 70.95% and 29.05%, respectively G‡B The frequencies of AA AAG AGG genotype in hOCT1- M408V were 28.37%,52.70%,18.92% Gthe allele A AG frequencies were 54.73% and 45.27%, respectively. The genotypes of hOCT1- P283L, R287G, M408V in 2 Tibetan nationality Chinese were CC ACC AAG and CC ACG AAG, respectively. In the CML patients with suboptimal response (group IIa), the frequency of hOCT1-283T allele was predominant, which was 55.56%, compared with that of 30.77% in the optimal response group(group I). The difference in the frequency distribution of hOCT1-P283L allele between two groups was statistically significance(X2=5.406,P=0.020). The frequencies of CC ACG AGG genotype of hOCT1-R287G in patients with suboptimal response group(group IIa) were 38.89%,61.11%,0 Gcompared with that of 57.69%,30.77%,11.54% in patients with optimal group (group I). A significant difference was found in the frequency distribution of hOCT1-R287G genotype between two groups(X2=6.149,P=0.046). In group IIa, the CG genotype was more common than group I, but no GG genotype. Non-significant difference was found in the frequency distribution of hOCT1-P283L, R287G, M408V genotype and allele between patients with failure response group (group IIb) and group IIa. Non-significant difference was found in the frequency distribution of hOCT1- M408V genotype and allele among the 3 groups: I AIIa and IIb (X2 =0.268,P=0.874 GX2a =0.988,Pa=0.610 GX2b =2.819, Pb=0.244). Conclusion Three coding single nucleotide polymorphisms (cSNP) --- hOCT1- P283L, R287G, M408V, were found in the human Organic Cation Transporter 1 gene from 74 Chinese Han individuals. The frequency distributions of their genotype and allele were different from that reported by others. The polymorphisms of hOCT1-R287G, M408V were found in 2 Tibetan nationality Chinese subjects. In this current study, hOCT1 gene polymorphism was associated with the long-term molecular response of CML patients administered with IM, the CG genotype of hOCT1-R287G and T allele of hOCT1- P283L in the suboptimal response group are prevalent; there is no specific association between hOCT1-M408V and patients’ response. This indicated that the polymorphism of hOCT1- P283L, R287G might be a valuable factor in predicting patients’ response. In our study, there was no specific correlation between the polymorphism of hOCT1- P283L, R287G, M408V and CML patients resistant to IM secondarily.

Purpose: The objective of this study was to evaluate the efficacy and potential toxicity of the Hyper-CVAD/MTX-Ara-C regimen,a dose-intensive regimen, in the patients with acute lymphocytic leukemia (ALL) and highly aggressive non-Hodgkin lymphoma (NHL) in China. PATIENTS AND METHODS: Between June 2004 and June 2007, fifty-six patients with ALL or highly aggressive lymphoma were treated with the Hyper-CVAD/MTX-Ara-C regimen at our institution. Median age was 26 years (range 13 to 60 years), and 35 patients (62.50%) were male. All patients were comprised of 32 previously untreated cases and 24 refractory/relapsed ones. Among the 41 patients with ALL, B-cell disease was present in 82.93%, T-cell disease in 17.07%, and Ph-positive ALL was present in 14.63%, refractory/relapsed disease in 43.90%. Among the 15 patients with highly aggressive NHL, lymphoblastic lymphoma was present in 46.67%, Burkitt’s lymphoma was in 53.33% and refractory/relapsed disease in 40.00%. CNS involvement was present in 8% at diagnosis. Treatment consisted of four cycles of Hyper-CVAD alternating with four cycles of high-dose methotrexate (MTX) and cytarabine therapy, together with intrathecal CNS prophylaxis and aggressive supportive care with granulocyte colony-stimulating factor (G-CSF), transfusion and antibiotic prophylaxis therapy. Maintenance therapy based on cytogenetics and immunophenotypes in most of patients contained 2-year treatment with mercaptopurine, MTX, vincristine, and prednisone (POMP). RESULTS: The median follow-up time was 7 months (range 1+ to 37+ months). Of the previously untreated 31 patients, twenty-nine patients (93.55%) achieved complete remission (CR) and no patients died during induction therapy. Of the refractory /relapsed 24 patients, fourteen cases (58.33%) achieved CR. Remarkably, the CR rate of the patients with Burkitt’s lymphoma was 75.00% (6/8). The median courses finished during the dose-intensive phase were 4 (range 1 to 8), and the median time to delivery of all eight courses was 10 months. The estimated 3-year overall survival (OS) for the untreated and refractory/relapsed patients with ALL was 46.80% and 28.60%, respectively. Meanwhile, the estimated 2-year OS for the aggressive NHL patients was 84.00%. Compared with the patients with ALL who did not receive CR and get less than four courses of this regimen, the patients who did receive CR and get more than four courses of this dose-intensive regimen showed much better OS (p CONCLUSION: The present outcome from our single center in China demonstrated that Hyper-CVAD/MTX-Ara-C, a dose-intensive regimen with much higher CR was superior to our previous regimens, even in patients with highly aggressive lymphoma such as lymphoblastic and Burkitt’s lymphoma, and in refractory/relapsed ALL/lymphoma ones. Our study also showed that this regimen was less toxic and well tolerated in most of treated patients in China. Long-term treatment benefits and severe side effects needed further investigation in a well-designed, multiple-center study in China with more eligible patients entering onto the study.

Objective To establish an imatinib resistance cell line and to study its resistant principia. Methods K562 cells were cultured in imatinib at gradually increased concentrations to generate their resistance cell line. Clone imatinib resistance cell lines by limited dilution culture. MTT assay, real time PCR and Semi-quantity PCR, flow cytometry and HPLC were used to clarify the possible mechanisms of the resistance. Results Imatinib resistance cell line K562R was successfully induced by continuous culture in the presence of gradually increasing doses of imatinib up to 5μmol/L. K562R cells were maintained in the media containing 5μmol/L imatinib. Proliferation data showed that cell growth of K562R was not inhibited in 5 μmol/L imatinib, whereas the parental sensitive cell was significantly inhibited by up to 2μM imatinib. The IC50 of K562R was about 7.5μmol/L which was ten times higher than that of the parental cell. HPLC revealed that the intracellular imatinib concentration of K562R was strikingly lower than that of the parental cells (up to 27.8-fold). MDR1 were not detected in mRNA (by RT-PCR)and protein(by flow cytometry) levels on K562R cell, whereas hOCT1 level measured by semi-quantity PCR showed lower expression in K562R cell lines than that of parental sensitive cell, indicating that low intracellular imatinib concentration may be due to lower affluence of imatinib by low level of hOCT1. (5) Real time PCR analysis showed no BCR-ABL/G6PD gene amplification and sequence analysis of the 374bp ABL kinase domain showed no mutation in K562R cell lines. Conclusion An imatinib resistance cell line K562R has been successfully established. Low expression of hOCT1 may be a key point mediating low intracellular imaitnib accumulation in K562R cell lines.

BACKGROUND: Although the safety and efficacy of the Hyper-CVAD/MTX-Ara-C regimen in hematologic malignancies has been well established by the large clinical trials developed at the University of Texas M. D. Anderson Cancer Center, the outcome with this regimen in patients in China has not been determined. The objective of this study was to evaluate the efficacy and potential toxicity of this regimen in acute lymphocytic leukemia (ALL) and highly aggressive non-Hodgkin lymphoma (NHL) in a single center in China. PATIENTS AND METHODS: Between September 2004 and July 2006,36 patients with ALL or highly aggressive lymphoma were treated with the Hyper-CVAD/MTX-Ara-C regimen at our institution. Median age was 35 years (range 14 to 60 years), and 23 patients (64%) were male. All patients are comprised of 19 previously untreated cases and 17 refractory/relapsed ones. Among the 28 patients with ALL, B-cell disease was present in 82%, T-cell disease in 18%, and Ph-positive ALL was present in 18%, refractory/relapsed disease in 46%. Among the 8 patients with highly aggressive NHL, lymphoblastic lymphoma was present in 63%, Burkitt’s lymphoma was in 37% and refractory/relapsed disease in 50%. CNS involvement was present in 8% at diagnosis. Treatment consisted of four cycles of Hyper-CVAD alternating with four cycles of high-dose methotrexate (MTX) and cytarabine therapy, together with intrathecal CNS prophylaxis and aggressive supportive care with granulocyte colony-stimulating factor, transfusion and antibiotic prophylaxis therapy. Maintenance therapy according to cytogenetics and immunophenotype in partial patients included 2 years of treatment with mercaptopurine, MTX, vincristine, and prednisone (POMP). RESULTS: The median follow-up was 7 months (range 1+ to 23+ months). Of the previously untreated 19 patients, seventeen patients (89.47%) achieved complete remission (CR) and no patients died during induction therapy. Of the refractory/relapsed 17 patients, seven cases (41.48%) achieved CR. Remarkably, the CR rate of the patients with Ph-positive ALL was 60.00%(3/5), and Burkitt’s lymphoma 66.67%(2/3). The median finished courses during the dose-intensive phase were 5 (range 1 to 8), and the median time to delivery of all eight courses was 10 months. The estimated 5-year survival and 5-year CR rates were not concluded so far. The incidence of CNS relapse was low (5%). Myelosuppression-associated complications including documented infections, fever of unknown origin, hemorrhage were the more frequent side effects. Other significant side effects included neurotoxicity, renal and hepatic toxicities, fatigue, mucositis, nausea, vomiting, diarrhea, skin rashes, and G-CSF therapy-associated bone aches. CONCLUSION: The preliminary experience from our single center in China demonstrated that Hyper-CVAD/MTX-Ara-C, a dose-intensive regimen with much higher CR is superior to our previous regimens, even in poor-risk Ph-positive ALL, and highly aggressive lymphomas such as lymphoblastic and Burkitt’s lymphoma, and refractory/relapsed ALL/lymphoma. Our data also showed that this regimen is less toxic and well tolerated in patients. Due to the aggressive supportive care, the expense with this regimen is more expensive than conventional chemotherapy. Long-term treatment benefits, such as disease-free survival rates and severe side effects need further investigation in a well-designed, multiple-center study in China with more eligible patients entering onto the study.

Imatinib mesylate is a selective tyrosine kinase inhibitor that is effective in the treatment of Philadelphia-positive chronic and acute leukemia. Unfortunately disease recurrence due to drug resistance is still the challenge to obtain cure. To investigate the possible mechanisms of imatinib resistance, we established a BCR/ABL+ cell line with resistance to imatinib (K562-R) by culturing a wild-type K562 cell line (K562-W) in gradually increased concentrations of imatinib over a period of 6 months, which can survive and was maintained in vitro at 3.0 umol/L of imatinib. K562-W and K562-R cells were cultured to logarithmic phase without imatinib, then treated with imatinib at 3.0 umol/L for 2 hours with or without cyclosporin A (2 ug/ml). The cells were washed thoroughly and incubated for further 0, 15, 30 and 60 minutes. Then cell suspensions containing 2×106 cells was measured for imatinib intracellular concentrations by High-Performance Liquid Chromatography (HPLC) after repeated freezing and thawing these cells. The imatinib concentration of K562-W cell is 0.31 umol/L, which is stable even after incubation for 1 hour. The imatinib concentration of K562-R is decreased significantly, being 0.21, 0.08, 0.06 and less than 0.01 umol/L at different incubation times mentioned above. The high level of cyclosporin A showed no effects on imatinib concentrations of both K562-W and K562-R cells. Flow cytometry showed there was no MDR expression of K562-R, whereas there was a small population (about 20%) of K562-W cells with dim expression of MDR. Compared to K562-W cells, the copies of BCR/ABL fusion genes determined by the real-time PCR showed that there were no amplifications of the fusion genes in K562-R cells and BCR/ABL cDNA sequencing showed no mutations of the imatinib ATP binding sites. The western blot assay showed that the expression of heat shock protein 90(Hsp90) was increased in K562-R cells. These results indicate that the intracellular eliminations of imatinib may be one of possible mechanisms for K562-R cells and Hsp90 as a critical molecular chaperone might be involved in the process.

Acquired pure red cell aplastic anemia(PRCA)is a group of heterogeneneous disorders characterized by erythropoiesis failure or disorder in bone marrow. PRCA is often associated with thymoma, large granular lymphocytic leukemia, and also some autoimmune diseases. It has been well documented that T cell subsets from the patients with PRCA often show some abnormalities either in quantum or in the effects to suppress erythropoiesis, and anemia symptom of the patients usually have a good response to cyclosporine treatment. So it suggested that activated T cell might play a key role in the pathogenesis of PRCA. This study is to explore the abnormalities of γδT cell subsets and the effects of immunosuppressive therapy in the PRCA patients. Methods: 12 patients, whose age ranged 37~72 years old, were diagnosed as PRCA based on bone marrow smear and biopsy, and were treated with cyclosporine, and 24 healthy adults were matched as normal controls. The three-color flowcytometry technique was used for lymphocytes subsets and γδT cells analyses. Furthermore, peripheral mononuclear cells (MNC) isolated from PRCA patients were cultured in RPMI1640 medium (106 cells/ml) with 10% FCS, phytohemagglutinin(PHA, 10μg/ml), and recombinant human interleukin-2(rIL-2, 50U/ml)for two weeks, then γδT cells were isolated with the TCRγδ Microbead Kit from cultured cells. The collected γδT cells were incubated with normal control bone marrow MNC in RPMI1640 medium (37°, 5% CO2 atmosphere) for CFU-E, CFU-GM, and BFU-E clones assay. Results: Comparing with control group, CD3+/CD8+ cells were increased significantly in the patients group (p Conclusion: Our study suggested that γδT cells might impacted to pathogenesis of acquired PRCA, a significant improvement of anemia symptoms had been shown after cyclosporine treatment, meanwhile, the percentage of γδT cells recovered to normal range, and it is very interesting, the γδT cells isolated from PRCA patients show an inhibiting role to CFU-E and BFU-E but not to CFU-GM in vitro culture. We think that it is an effective way to treat the patients with acquired PRCA by to rectify the abnormal cellular immunity.