Case report: Plasma cell leukemia secondary to multiple myeloma successfully treated with anti-BCMA CAR-T cell therapy.

Chimeric antigen receptor (CAR)-T cell therapy provides an effective salvage treatment for relapsed/refractory multiple myeloma (RRMM) patients. End-stage RRMM with plasma cell leukemia (PCL) transformation is highly aggressive and resistant to conventional therapy. There is an urgent need for new therapeutics and CAR-T therapy may play an important role. We report a case of PCL secondary to RRMM successfully treated with CAR-T cell therapy targeting B-cell maturation antigen (BCMA). A woman was diagnosed as having MM 4 years ago and progressed to secondary PCL (sPCL) of five prior lines of treatment including proteasome inhibitors, an immunomodulatory agent, cytotoxic drugs, and an anti-CD38 monoclonal antibody. After receiving a BCMA CAR-T therapy, she achieved a stringent complete response that lasted 9 months. Then, the patient irregularly took venetoclax 10 mg per day due to a slightly higher λ FLC concentration, which did not meet the criteria for progression. She maintained a complete response for the following 7 months. In conclusion, BCMA CAR-T therapy may be a promising therapeutic approach in PCL patients. More studies are needed to evaluate the benefit of anti-BCMA CAR-T therapy in PCL patients. Clinical Trial Registration: www.chictr.org.cn, ChiCTR1900024388, Registered 9 July 2019.

CAR-T therapy as a consolidation in remission B-ALL patients with poor prognosis.

BACKGROUND: To date, almost all studies regarding chimeric antigen receptor (CAR)-T cell therapy for B-cell acute lymphoblastic leukemia (B-ALL) were performed in refractory/relapsed (r/r) or minimal residual disease-positive patients. CAR-T therapy in remission patients has not been reported. AIM: To observe the treatment outcome of CAR-T cells for remission B-ALL patients with poor prognosis. METHODS AND RESULTS: CAR-T treatment was applied to two B-ALL patients in remission status who had poor prognostic factors and refused transplantation, and one case was unable to accept standard chemotherapy owing to multiple complications. The procedure of CAR-T therapy in these two remission patients was the same as that in r/r B-ALL patients. Lentiviral vectors encoding second generation CARs composed of CD3ζ and 4-1BB were used to produce CAR-T cells. Lymphodepleting agents fludarabine and cyclophosphamide were administered prior to cell infusion. Grade I cytokine release syndrome occurred after each T-cell infusion and there was no neurotoxicity. CAR-T treatment followed by non-intensive maintenance chemotherapy and targeted drugs allowed both patients to obtain a long-term event-free survival of more than three and a half years without transplantation. CONCLUSIONS: CAR-T therapy could be used in high-risk B-ALL patients as a consolidation to avoid transplantation, the combination of CAR-T and following maintenance therapy may be better than CAR-T alone for durable remission.

Humanized CD19 CAR-T cells in relapsed/refractory B-ALL patients who relapsed after or failed murine CD19 CAR-T therapy.

BACKGROUND: For CD19-positive relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL) after treatment with murine CD19 (mCD19) CAR-T, the reinfusion of mCD19 CAR-T cells may be ineffective due to anti-mouse single-chain variable fragment (scFv) antibody caused by mCD19 CAR. To overcome this immunogenicity, we applied humanized CD19 (hCD19) CAR-T cells to treat r/r B-ALL patients with prior mCD19 CAR-T therapy. METHODS: Nineteen pediatric and adult patients were included, 16 relapsed after and 3 were primarily resistant to mCD19 CAR-T. All patients presented with more than 5% blasts in bone marrow and/or extramedullary disease, and still showed CD19 antigen expression. Humanized CD19-CARs were lentiviral vectors carrying a second generation CAR with 4-1-BB co-stimulatory and CD3ζ signaling domains. Patient-derived cells were collected for producing CAR-T cells, the median dose of infused hCD19 CAR-T cells was 2.4 × 105/kg (range, 1.0-18.0 × 105/kg). RESULTS: hCD19 CAR-T resulted in a complete remission (CR) rate of 68% (13/19). Among 13 remission patients, 11 underwent allogeneic hematopoietic cell transplantation (allo-HCT) (3 were second HCT) and 10 remained in CR; the event-free survival rates at 12-18 months were 91% in 11 patients received following allo-HCT and 69% in all CR patients. Six cases had no response to hCD19 CAR-T, 3 died of disease progression; another 3 received salvage second transplantation, of them, 2 relapsed again (one died). Cytokine release syndrome (CRS) occurred in 95% (18/19) of patients, most CRS events were grade 1 and grade 2 (n = 17), there was only one grade 4 CRS. Two cases experienced grade 1 neurotoxicity. CONCLUSIONS: Humanized CD19 CAR-T cell therapy could be a treatment option for CD19-positive B-ALL patients who relapsed after or resisted prior murine CD19 CAR-T, hCD19 CAR-T followed by allo-HCT provided a longer remission in CR patients. Nevertheless, the prognosis of non-responders to hCD19 CAR-T remained dismal. TRIAL REGISTRATION: Chinese Clinical Trial Registry/WHO International Clinical Trial Registry ( ChiCTR1900024456 , URL: www.chictr.org.cn ); registered on July 12, 2019.

Sequential different B-cell antigen-targeted CAR T-cell therapy for pediatric refractory/relapsed Burkitt lymphoma.

Single antigen-targeted chimeric antigen receptor (CAR) T-cell therapy may be insufficient to induce a durable response in pediatric aggressive B-cell lymphomas. This clinical trial examined the feasibility of sequential different B-cell antigen-targeted CAR T-cell therapy for pediatric relapsed/refractory (R/R) Burkitt lymphoma. Twenty-three patients received the first CD19 CAR T-cell infusion. The patients who did not achieve an ongoing complete response (CR) underwent 1 or more sequential infusions of CAR T-cell therapy that targeted CD22 followed by CD20 according to their disease status and CAR T-cell persistence after each infusion. The median time from the last infusion to the cutoff date was 17 months (range, 15-23 months). The estimated 18-month CR rate was 78% (95% confidence interval [CI], 54%-91%). The estimated 18-month progression-free survival rate was 78% (95% CI, 55%-90%), with 78% (95% CI, 37%-94%) in patients with bulky disease and 60% (95% CI, 25%-83%) in patients with central nervous system (CNS) involvement. During the first CD19 CAR T-cell infusion, grade ≥3 cytokine release syndrome (CRS) occurred in 34.8% and neurotoxicity occurred in 21.7% of all patients. During subsequent infusions, there were only a few incidences of grade >2 CRS and neurotoxicity. All adverse events were reversible. The severity of neurotoxicity was not significantly different between patients with CNS involvement and those who did not have CNS involvement. Sequential CAR T-cell therapy may result in a durable response and is safe in pediatric R/R Burkitt lymphoma. Patients with CNS involvement may benefit from sequential CAR T-cell therapy. This trial was registered at www.chictr.org.cn/index.aspx as #ChiCTR1800014457.

Peripheral leukemia burden at time of apheresis negatively affects the clinical efficacy of CART19 in refractory or relapsed B-ALL.

Our previous clinical study achieved complete remission (CR) rates of >90% following chimeric antigen receptor T cells targeting CD19 (CART19) treatment of refractory/relapsed B cell acute lymphoblastic leukemia (r/r B-ALL); however, the influence of the leukemia burden in peripheral blood (PB) blasts remains unclear. Here, we retrospectively analyzed 143 patients treated with CART19 (including 36 patients with PB blasts) to evaluate the effect of peripheral leukemia burden at the time of apheresis. One hundred seventeen patients with high disease burdens achieved 91.5% CR or incomplete count recovery CR and 86.3% minimal residual disease-negative CR, and 26 patients with low disease burdens obtained 96.2% MRD- CR. Collectively, 9 of 36 (25%) patients with PB blasts and 2 of 107 (1.87%) patients without PB blasts did not respond to CART19 therapy. The leukemia burden in PB negatively influenced ex vivo cell characteristics, including the transduction efficiency of CD3+ T cells and their fold expansion, and in vivo cell dynamics, including peak CART19 proportion and absolute count, fold expansion, and persistence duration. Further studies showed that these patients had higher programmed death-1 expression in CART19 products. Our data imply that PB blasts negatively affected CART19 production and the clinical efficacy of CART19 therapy in patients with r/r B-ALL.

Combination of CD19 and CD22 CAR-T cell therapy in relapsed B-cell acute lymphoblastic leukemia after allogeneic transplantation.

The prognosis of relapsed acute lymphoblastic leukemia (ALL) after allogeneic transplantation is dismal when treated with conventional approaches. While single-target CD19 or CD22 chimeric antigen receptor (CAR) T-cell therapy has achieved high complete remission (CR) rates in refractory/relapsed B-ALL, it could not maintain a durable remission in most patients. To prolong relapse-free survival, we sequentially combined CD19 and CD22 CAR-T cells to treat post-transplant relapsed B-ALL patients with both CD19/CD22 antigen expression on lymphoblasts. Patient-derived donor cells were collected to produce CAR-T cells that were transfected by lentiviral vectors encoding second generation CARs composed of CD3ζ and 4-1BB. The second T-cell infusion was scheduled at least 1 month, and usually within 6 months after the first CAR-T treatment. Twenty-seven adult and pediatric patients, including 11 (41%) with extramedullary diseases (EMD), received the first CD19 CAR-T and 23 (85%) achieved CR. Subsequently, 21 out of 27 patients received the second CD22 CAR-T and were followed-up for a median of 19.7 (range, 5.6-27.3) months; 14 cases remained in CR, seven relapsed and two of them died from disease progression; Kaplan-Meier survival analysis showed overall survival and event-free survival rates of 88.5% and 67.5%, respectively, at both 12 months and 18 months. CAR-T associated graft-versus-host disease (GVHD) occurred in 23% of patients, with 8% new-onset acute GVHD and 15% persistent or worsened pre-existing cGVHD before CAR-T. This combination strategy of sequential CD19 and CD22 CAR-T therapy significantly improved the long-term survival in B-ALL patients who relapsed after transplantation.

Post-HSCT relapsed precursor B-cell ALL successfully salvaged by BiTE followed by consolidation CAR-T cell therapy: A report of two cases.

Precursor B-cell acute lymphoblastic leukemia (pre-B ALL) relapse after allogeneic hematopoietic stem cell transplantation (HSCT) typically has poor outcomes. Both bispecific T-cell engager (BiTE, blinatumomab) and chimeric antigen receptor T-cell (CAR-T) are novel immuno-designed therapies for advanced acute lymphoblastic leukemia. However, the treatment and effects of their combination remain unclear. Two patients with pre-B ALL experienced overt leukemic relapse after allogeneic HSCT. Both patients received one standard cycle of blinatumomab treatment, and complete remission was achieved. Subsequently, during remission, both patients underwent treatment with CAR-T cells prepared from their own T-cells. One patient received CD22-CAR-T cell as a consolidative therapy, while the other underwent CD19-CAR-T cell therapy. No cytokine release syndrome occurred. After treatment, both patients are alive and do not have leukemia recurrence for more than one year. In conclusion, sequential combination of BiTE followed by CAR-T cell therapy may show promising results for relapsed and advanced B-cell leukemia. This novel combination is worthy of further investigation.

CD22 CAR T-cell therapy in refractory or relapsed B acute lymphoblastic leukemia.

Despite worldwide promising clinical outcome of CD19 CAR-T therapy, relapse after this therapy is associated with poor prognosis and has become an urgent problem to be solved. We conducted a CD22 CAR T-cell therapy in 34 relapsed or refractory (r/r) B-ALL pediatric and adult patients who failed from previous CD19 CAR T-cell therapy. Complete remission (CR) or CR with incomplete count recovery (CRi) was achieved in 24 of 30 patients (80%) that could be evaluated on day 30 after infusion, which accounted for 70.5% of all 34 enrolled patients. Most patients only experienced mild cytokine-release syndrome and neurotoxicity. Seven CR patients received no further treatment, and 3 of them remained in remission at 6, 6.6, and 14 months after infusion. Eleven CR patients were promptly bridged to transplantation, and 8 of them remained in remission at 4.6 to 13.3 months after transplantation, resulted in 1-year leukemia-free survival rate of 71.6% (95% CI, 44.2-99.0). CD22 antigen loss or mutation was not observed to be associated with relapsed patients. Our study demonstrated that our CD22 CAR T-cells was highly effective in inducing remission in r/r B-ALL patients, and also provided a precious window for subsequent transplantation to achieve durable remission.

Germline cytotoxic lymphocytes defective mutations in Chinese patients with lymphoma.

Certain patients with lymphoma may harbor mutations in perforin 1 (PRF1), unc-13 homolog D (UNC13D), syntaxin 11 (STX11), STXBP2 (syntaxin binding protein 2) or SH2 domain containing 1A (SH2D1A), which causes functional defects of cytotoxic lymphocytes. Data regarding the association between genetic defects and the development of lymphoma in Chinese patients are limited to date. In the present study, 90 patients with lymphoma were analyzed for UNC13D, PRF1, STXBP2, STX11, SH2D1A and X-linked inhibitor of apoptosis. Mutations were observed in 24 (26.67%) patients; 16 patients exhibited mutations in UNC13D, 7 exhibited PRF1 mutations, and 1 exhibited monoallelic mutation in STX11. UNC13D c.2588G>A/p.G863D mutation was detected in 9 patients (10.00%) and in 4/210 controls (1.90%). This mutation was predicted to be pathogenic and it predominantly existed in the Chinese population. These findings suggest that impaired cytotoxic machinery may represent a predisposing factor for the development of lymphoma. Furthermore, these data describe a distinct mutation spectrum in Chinese patients with lymphoma, whereby UNC13D is the most frequently mutated gene. In addition, these findings suggest UNC13D c.2588G>A mutation is a founder mutation in Chinese patients.

Impact of clinical factors on outcome of leukemia patients with TLS-ERG fusion gene.

We report the clinical features and outcome of 22 TLS-ERG+ leukemia patients (20 AML and 2 B-ALL). TLS-ERG was tightly associated with extramedullary disease (EMD), complex chromosome abnormalities, and high risk gene mutations including IKZF1, WT1, TET2, NOTCH2, and PHF6. The 6-month leukemia free survival (LFS) with and without EMD was 75% and 83.3% (p = .017). 11/20 AML patients received allogeneic hematopoietic stem cell transplantation (HCT). The 1-year overall survival (OS) in non-HCT and HCT group was 62.5% and 90% (p = .026), but the 6-month LFS in non-HCT and HCT group was 55.6% and 100% (p = .192). The 6-month LFS of patients with complete remission (CR) before HCT versus those with no response (NR) was 67.5% and 0, respectively (p = .034). In conclusion, the leukemia burden before HCT and EMD had negative impact on the outcome of TLS-ERG patients; HCT could prolong OS, but could not overcome the poor prognostic impact of TLS-ERG.

Maternal onset de novo SH2D1A mutation and lymphocytic choriomeningitis virus infection in a patient with X­linked lymphoproliferative disease type 1: a case report.

X­linked lymphoproliferative disease type 1 (XLP1) is a rare genetic immunodeficiency disease, which occurs due to germline mutations in the SH2D1A gene. This gene has been reported to encode the adaptor molecule signaling lymphocytic activation molecule­associated protein XLP1 is generally triggered by the Epstein­Barr virus (EBV) infection. The present study reported the case of a 4­year­old male who presented with a high fever, hypogammaglobulinemia, diffuse lung disease and encephalitis. The patient was infected with the lymphocytic choriomeningitis virus (LCMV), not EBV or any other human herpes virus. The patient was found to carry a SH2D1A c.7G>T/p.A3S mutation, which was inherited from the mother and maternal grandfather, as well as a SH2D1A c.228T>A/p.Y76X mutation, which was identified to be a maternal­onset de novo mutation at the time of germline development of the patient's mother. To the best of our knowledge, the present study is the first reported case of maternal­onset XLP1 with a de novo SH2D1A mutation and LCMV infection.

[Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in Chinese children: a primary study on clinical characteristics and gene mutations].

OBJECTIVES: To study the clinical features and gene mutations of EBV-HLH in Chinese children. METHODS: Sixteen pediatric patients with Epstein-Barr virus-associated HLH were enrolled the study from May 2011 to September 2012, who were admitted to Capital Institute of Pediatrics. All patients' clinical features were recorded and their nucleotide sequences of all exons and their flanking intronic sequences of perforin (PRF1) gene, protein unc-13 homolog D (UNC13D) gene, two fusion protein genes of syntaxin 11 (STX11)gene, synaptic binding protein 2 (STXBP2) gene, SH2 domain 1A (SH2D1A) gene, and the X-linked inhibitor of apoptosis protein (XIAP) gene were amplified by PCR followed by direct sequencing. Based on HLH gene detection results, all patients divided into the positive and negative gene EBV-HLH subgroups. Statistical analysis was conducted using SPSS 11.5 software. RESULTS: Seven of sixteen pediatric patients with EBV-HLH were identified with heterozygous, hemizygous, and homozygous mutations in PRF1, UNC13D, STXBP2, and SH2D1A. No significant differences were found on the gender, age, illness duration, EBV load, the positive duration of EBV-DNA, lab results, clinical symptoms, treatment, and the outcome between the HLH gene positive and negative subgroups (P > 0.05). CONCLUSIONS: A considerable EBV-HLH pediatric patients have genetic defects, and HLH gene defects may not affect the clinical features and treatment of EBV-HLH pediatric patients.

The Role of HLA Antibodies in HLA Mismatched Allogeneic Hematopoietic Stem Cell Transplantation.

Published reports suggest that engraftment failure after hematopoietic stem cell transplantation (HSCT) is closely associated with the presence of donor-specific HLA antibodies (DSA). Herein, we report a single cohort retrospective analysis of 567 cases of HLA mismatched allogeneic HSCT patients from the Lu Dao-pei Hematology Center, transplanted between September 11, 2012, and November 20, 2014. Of these cases, 306 patients underwent HLA class I and II antibody testing within one month before transplantation. For patients with HLA antibody screening resulting in an HLA antibody with a mean fluorescence intensity (MFI) > 1000, single antigen bead HLA class I and II testing was performed. Then, according to donor HLA genotype, we determined whether DSA were present. Of the 306 patients with pre-transplant HLA antibody screening (LABScreen Mixed Antigen), HLA class I antibodies were present in 51 cases (16.7%). HLA class II antibodies were present in 24 cases (7.8%). Of all antibody positive cases, 20 cases were positive for HLA antibodies on single antigen beads at an MFI > 1000. Half of these cases were DSA positive. Of the non-DSA antibody cases (n = 1 0), there was one case of primary graft failure after HSCT. In the ten DSA positive patients, the HSCT was chosen from the reactive donor. Seven of these cases were treated prior to HSCT with 1-2 times plasmapheresis or high-dose intravenous immunoglobulin (IVIG) therapy. The other three cases had no special treatment to decrease HLA antibodies before transplantation. All 10 DSA positive cases achieved successful engraftment. There was one case of primary graft failure in the group of 273 patients who were HLA antibody negative. Out of the group of 261 patients who did not undergo HLA antibody screening, there were 7 cases of primary engraftment failure. The incidence of engraftment failure was lower in the group of patients who had been screened for HLA antibodies prior to transplant than it was for the patients who had not been screened (2/306 versus 7/261, p = 0.054). Five of the 7 cases of engraftment failure were screened for HLA antibodies at 30 days after first transplantation. The results of five of the cases were negative for HLA antibodies and the patients underwent second transplants, all achieving successful engraftment. This cohort researched HLA antibodies and their effect on engraftment of HSCT in Chinese cases. We compared 306 patients who underwent HLA antibody screening and were given the appropriate treatment before HSCT if DSA were positive, with 261 patients who were not screened for HLA antibodies. We found that the incidence of primary graft failure significantly decreased. Although not directly determined, HLA antibodies (especially DSA) are the cause of engraftment failure and our findings reflect the importance of HLA antibody screening prior to transplantation. We suggest that patients with pre-existing DSA should be treated with plasma exchange or IVIG therapy before transplantation.

[Acute myeloid leukemia with t(11;22) (q23;q11.2): two cases report and literature review].

OBJECTIVE: To report two de novo acute myeloid leukemia (AML) patients with t(11;22)(q23;q11.2) and summarize the clinical and biological characteristics. METHODS: Bone marrow cells morphology, immunophenotype, chromosome karyotype, fluorescence in situ hybridization (FISH), PCR and gene sequencing were performed. Clinical manifestation and routine laboratory tests were analyzed. RESULTS: The patients were diagnosed as AML-M2 and AML-M5 by morphology and immunophenotype results. Both patients carried t(11;22)(q23; q11.2) and one of them carried an additional chromosome abnormality. MLL-SEPTIN5 fusion transcript was identified in two patients by RT-PCR and sequencing. The two patients got hematologic complete remission after induction chemotherapy with daunorubicin, homoharringtonine, and cytarabine (DHA) or daunorubicin and cytarabine (DA). One of them relapsed and died during consolidation therapy with intermediate-dose cytarabine. CONCLUSION: Leukemia with t(11;22)(q23;q11.2) chromosome translocation met the clinical and laboratory manifestations of AML. The MLL-SEPTIN5 fusion transcript was the distinctively biological etiology. Patients with t(11;22)(q23;q11.2) were vulnerable to relapse after conventional chemotherapy and had poor prognosis. Allogeneic hematopoietic stem cell transplantation should be recommended as early as possible.

Stem cell factor SALL4, a potential prognostic marker for myelodysplastic syndromes.

BACKGROUND: Myelodysplastic syndromes (MDS) are a group of heterogeneous diseases with variable clinical course. Predicting disease progression is difficult due to lack of specific molecular marker(s). SALL4 plays important roles in normal hematopoiesis and leukemogenesis. SALL4 transgenic mice develop MDS prior to acute myeloid leukemia (AML) transformation. However, the role of SALL4 in human MDS has not been extensively investigated. In this study, we evaluate the diagnostic/prognostic value of SALL4 in MDS by examining its expression levels in a cohort of MDS patients. METHODS: Fifty-five newly diagnosed MDS, twenty MDS-AML, and sixteen post-treatment MDS patients were selected for our study along with ten healthy donors. RESULTS: We demonstrated that SALL4 was over-expressed in MDS patients and proportionally increased in MDS patients with high grade/IPSS scores. This expression pattern was similar to that of Bmi-1, an important marker in predicting MDS/AML progression. In addition, the level of SALL4 was positively correlated with increased blast counts, high-risk keryotypes and increased significantly in MDS-AML transformation. Furthermore, higher level of SALL4 expression was associated with worse survival rates and SALL4 level decreased following effective therapy. CONCLUSIONS: To the best of our knowledge, this is the largest series and the first to report the expression pattern of SALL4 in detail in various subtypes of MDS in comparison to that of Bmi-1. We conclude that SALL4 is a potential molecular marker in predicting the prognosis of MDS.