Case report: CD38-directed CAR-T cell therapy: A novel immunotherapy targeting CD38- positive blasts overcomes TKI and chemotherapy resistance of myeloid chronic myeloid leukemia in blastic phase.

Resistance to tyrosine kinase inhibitor (TKI) is a tough problem in the treatment of chronic myeloid leukemia in blastic phase (CML-BP), which was often associated with acquired mutations in the kinase domain and not eliminating the leukemic stem cells. The efficacy of TKI or combination with chemotherapy in CML-BP remains unsatisfactory. Chimeric antigen receptor T (CAR-T) cell immunotherapy may overcome TKI and chemotherapy resistance. However, lack of ideal targetable antigens is a major obstacle for treating patients with myeloid malignancies. CD38 is known to be expressed on most (acute myeloid leukemia) AML cells, and its lack of expression on hematopoietic stem cells renders it as a potential therapeutic target for myeloid CML-BP. We develop a CD38-directed CAR-T cell therapy for AML, and two patients with myeloid CML-BP were enrolled (NCT04351022). Two patients, harboring E255K and T315I mutation in the ABL kinase domain, respectively, were resistant to multiple TKIs (imatinib, dasatinib, nilotinib, and ponatinib) and intensive chemotherapy. The blasts in the bone marrow of two patients exhibited high expression of CD38. After tumor reduction chemotherapy and lymphodepletion chemotherapy, 1 × 107 CAR-T-38 cells per kilogram of body weight were administered. They achieved minimal residual disease-negative and BCR::ABL1-negative complete remission and experienced grade II cytokine release syndrome manifesting as fever. Our data highlighted that CAR-T-38 cell therapy may overcome TKI and chemotherapy resistance in patients with myeloid CML-BP.

CD7-directed CAR T-cell therapy: a potential immunotherapy strategy for relapsed/refractory acute myeloid leukemia.

Relapsed/refractory acute myeloid leukemia (AML) patients generally have a dismal prognosis and the treatment remains challenging. Due to the expression of CD7 on 30% AML and not on normal myeloid and erythroid cells, CD7 is an attractive target for immunotherapy of AML. CD7-targeted CAR T-cells had demonstrated encouraging efficacy in xenograft models of AML. We report here on the use of autologous CD7 CAR T-cells in the treatment of a relapsed/refractory AML patient with complex karyotype, TP53 deletion, FLT3-ITD mutation, and SKAP2-RUNX1 fusion gene. Before the CAR T-cell therapy, the patient achieved partial remission with IA regimen and attained complete remission after reinduction therapy (decitabine and venentoclax). Relapse occurred after consolidation (CLAG regimen). Then she failed CLIA regimen combined with venetoclax and exhibited resistance to FLT3 inhibitors. Bone marrow showed 20% blasts (CD7+ 95.6%). A total dose of 5 × 106/kg CD7 CAR T-cells was administered after the decitabine +FC regimen. Seventeen days after CAR T-cells infusion, she achieved morphologic leukemia-free state. The patient developed grade 3 cytokine release syndrome. No severe organ toxicity or immune effector cell-associated neurotoxicity syndrome was observed. In summary, the autologous CD7 CAR T-cell therapy could be considered a potential approach for AML with CD7 expression (NCT04762485).Trial registration Clinical Trials.gov, NCT04762485. Registered on February 21, 2021, prospectively registered.

Successful treatment of secondary poor graft function post allogeneic hematopoietic stem cell transplantation with eltrombopag.

Poor graft function (PGF) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Current treatment strategies include the use of growth factors, CD34+-selected stem cell boost, mesenchymal stem cell transfusion, and second allo-HSCT, but these treatments are not effective in all patients. Eltrombopag, an oral thrombopoietin receptor agonist, which showed promising results in severe aplasia anemia, may be an alternative choice for PGF patients. Therefore, we treated 12 patients who responded poorly to standard treatments for secondary PGF after allo-HSCT with eltrombopag. The median duration was 116 (35-1000) days from transplantation to PGF diagnosis and 59 (30-180) days from PGF diagnosis to eltrombopag treatment. Eltrombopag was started at a dose of 25 mg/d for 3 days and then increased to 50 or 75 mg/d. Median treatment duration was 8 (2-23) weeks. Ten patients (83.3%) responded to the treatment: 8 achieved complete response (CR), and the remaining 2 achieved partial response. In the 10 responding subjects, median platelet count was 18 (5-27) × 109/L vs 74 (30-117) × 109/L prior to and after treatment. Neutrophil count was 0.51 (0.28-0.69) × 109/L vs 1.84 (0.78-4.90) × 109/L. Hemoglobin was 88 (63-123) vs 101 (78-134) g/L. In the 8 patients who achieved CR, the time from eltrombopag initiation to achieving CR was 29 (10-49) days; the response lasted until the last follow-up in all 8 CR subjects (10-18 months). The 12-month overall survival rate was 83.3%. There was no treatment-related mortality and no evidence of cataract, thrombosis, or any other grade 3/4 toxicities.

[Clinical and laboratory features of patients with CD34(+) acute promyelocytic leukemia].

OBJECTIVE: To explore the expression of CD34 in patients with acute promyelocytic leukemia (APL) and investigate the clinical and laboratory features of CD34(+) APL patients. METHODS: 262 APL patients diagnosed by chromosome analysis and/or fusion gene examination in the last five years were retrospectively analyzed in this study. To survey the expression of CD34 in those patients, all the cases were divided into two groups (CD34(+) APL vs. CD34(-) APL). The clinical features including age, gender, abnormal values of the peripheral hemogram before treatment, the complete remission (CR) rate and the incidence of DIC and laboratory data such as the results of morphology, immunology, cytogenetics and molecular biology (MICM) between those two groups were compared. RESULTS: Of the 262 APL patients, 38 (14.5%) cases were positive for CD34 expression. There were no statistically significant differences between CD34(+) APL and CD34(-) APL groups in gender and age (P > 0.05). Before treatment, the median level of WBC in CD34(+) APL was 25.92 x 10(9)/L, which was significantly higher than that of CD34(-) APL (5.3 x 10(9)/L, P < 0.05). CD34(+) APL by morphology classification were mostly of the subtypes M3b and M3v (65.8%), while these subtypes in CD34(-) APL (40.3%) were significantly less (P < 0.01). There were no statistically significant differences between the two groups compared in respect of complete remission (CR) rate and the incidence of DIC (P > 0.05). The expression level of CD34 in APL had correlation to the expression level of CD2, CD7 and CD117; the latter three phenotypes in CD34(+) APL were significantly higher than those in CD34(-) APL (P < 0.01). No significant difference was found between those two groups by chromosome analysis, but there was more PML-RAR-alpha transcript short form in CD34(+) APL than that in CD34(-) APL (P < 0.05). CONCLUSION: CD34(+) acute promyelocytic leukemia is a unique subtype of APL with different biological characteristics.

The significance of bone marrow cell morphology and its correlation with cytogenetic features in the diagnosis of MDS-RA patients.

Besides cytopenia, dysplasia is crucial characteristic of MDS-RA. To summarize the morphological features that contribute to the diagnosis of MDS-RA, 48 RA patients with abnormal karyotype were analyzed for the features of morphological and cytogenetical abnormalities and the relationships between them. 46 MDS-RA patients with normal karyotype and 207 patients with non-MDS anemia were enrolled into control groups. More conspicuous and diverse dysplasia can be found in abnormal karyotype MDS-RA than those in control groups (P<0.05). Apparent dysplasia in granulocyte and megakaryocytoid lineages may provide valuable evidence for the diagnosis. Dysplasia occurred more frequently in patients with severe chromosome abnormalities.

[Fluorescence in situ hybridization studies on a myeloid leukemia patient with ins(8;21)(q22;q22.1q22.3)].

OBJECTIVE: To report a case of acute myeloid leukemia (AML) with the insertion (8;21)(q22;q22.1q22.3). A 33-year-old Chinese woman was referred to our hospital. Hematologic data showed WBC 42.7 x 10(9)/L with monocytosis (monocyte counts 7.296 x 10(9)/L). Bone marrow aspirate was hypercellular with 4.5% monoblasts and 7.5% promonocytes. At first she was diagnosed with chronic myelomonocytic leukemia (CMML) according to the FAB criteria. Initially the patient received supportive care only, but her general condition rapidly became worse three months later. The monoblasts and promonocytes in the bone marrow rose to 20.5%. After two cycles of combined chemotherapy she obtained complete remission. METHODS: Chromosome specimens were prepared by short-term culture of bone marrow cells. Karyotype analysis was carried out by R-banding technique. Three fluorescence in situ hybridization (FISH) analyses were performed using AML1-ETO dual color, dual fusion probe, whole chromosome painting 8 and 21 probes, and cen-8 and Tel 21qter probes, respectively. Reverse transcription polymerase chain reaction (RT-PCR) assay for detecting the AML1-ETO fusion transcript was also performed. RESULTS: Conventional cytogenetic analysis showed a karyotype of 46,XX,ins(8;21) (q22;q22.1q22.3)[7]/46,XX[3]. FISH tests confirmed the insertion. RT-PCR analysis detected the AML1-ETO fusion transcript. CONCLUSION: We consider that this patient should be rediagnosed as acute myeloid leukemia according to the criteria proposed by World Health Organization (WHO) and that FISH and RT-PCR play an important role in verification of the ins(8;21).

[The clinical and laboratory features of acute promyelocytic leukemia: an analysis of 513 cases].

OBJECTIVE: To investigate the clinical and laboratory features of acute promyelocytic leukemia (APL). METHODS: 513 APL patients in the last two decades were retrospectively analyzed in this research. We investigated the clinical features including age, sex, abnormality of peripheral hemogram before treatment, therapeutic effect and follow-up and laboratory data such as morphology, immunology, cytogenetics and molecular biology (MICM). RESULTS: The median age of the APL patients was 33 years old and the ratio of male and female was 1.21:1. Before treatment, the median level of WBC was 4.3 x 10(9)/L and the detection rate of abnormal promyelocyte on blood film was 85.8%; with immunophenotypic detection, the expression levels of CD117, CD34, HLA-DR, CD7, CD14 and CD19 in APL were found to be lower and the expression levels of CD2, CD33 and MPO higher than those in other subtypes of acute myelocytic leukemia (AML) (both P < 0.01). Specific abnormal chromosome t (15;17) was detected in 91.7% of the patients, of whom 75.9% had standard translocation of t (15;17), being the most common one and 15.8% of the patients had t (15;17) with additional abnormal chromosome. There was only 7.5% of the patients with normal karyotype. However, the presence of both simple translocation and complex translocation was seldom seen. With molecular biological detection, PML/RARalpha fusion gene positive rate was 99.6%. In a relatively long clinical follow-up, we found that the complete remission (CR) rate in APL patients was 84.7%, incidence of DIC was 13.4% and five-year survival rate was 30.7%. The median count of WBC in CR group was lower than that non-remission group (P < 0.01). There were no significant differences on expressions of CD34 and CD2 and changes of cytogenetics between the two groups (P > 0.05). CONCLUSIONS: Comprehensive evaluation of MICM could be of important significance in the diagnosis and prognosis judgment for APL patients. The CR rate in these patients with high WBC count was considerable low.

[Immunophenotypic and cytogenetic features in 51 cases of chronic lymphocytic leukemia].

The study was aimed to investigate the immunophenotypic and cytogenetic features of chronic lymphocytic leukemia (CLL) in order to provide an evidence for diagnosis and therapy. Immunophenotypic analysis was performed by using a panel of monoclonal antibodies and three-color immunofluorescence staining methods of flow cytometry in 51 patients with CLL, and the cytogenetic features were analyzed by R-banding technique. The results indicated that among 51 CLL cases, the positive rate of CD19 and CD23 was 96.1%, followed by CD15 (94.1%), CD20 (82.4%) and CD22 (78.4%). The positive rate of CD38 was 23.5%. Forty-six patients expressed both CD5 and CD19. Seven main clonal chromosomal abnormalities were detected by conventional cytogenetics (CC) in eighteen cases (35.3%), with three cases of +12, two cases of 13q(-), other chromosomal abnormalities included +14, 6q(-), t (11; 14), t (14; 18) and t (2; 7). Expression of the antigens had no relationship with chromosomal abnormalities. It is concluded that typical CLL express CD5, CD19 and CD23, and the positive rate detected by CC in CLL is low. Immunophenotyping in combination with cytogenetic technique plays an important role in the diagnosis and prognosis of CLL.