Standardizing minimal residual disease by flow cytometry for precursor B lineage acute lymphoblastic leukemia in a developing country

Background: In addition to standard risk criteria at diagnosis, minimal residual disease (MRD) following initiation of therapy is a well‐recognized risk factor to predict relapse. Literature from developing countries addressing therapeutic or laboratory practices related to MRD, is largely lacking. In a first paper from India, we describe our experience in establishing a flow cytometry‐based MRD assay for precursor B lineage ALL (BCP‐ALL) with emphasis on the assay standardization and cost. Methods: Normal templates for B cell development were established in 10 control patients using CD45, CD11a, CD38, CD20, CD10, CD19, CD58, CD34, CD123, and CD22. BCP‐ALL samples (n = 42) were characterized at diagnosis to identify a suitable marker for follow‐up during mid (D+21) and end of induction (D+33). Both, multiparametric immunophenotyping and single marker detection of LAIP were used for data analysis. Results: In 95.2% of BCP‐ALL at least two informative markers could be obtained when a minimum of four cocktail combinations were used. The combination CD20, CD10, CD45, and CD19 was the most useful (71.4%) followed by combinations containing CD38 (66.7%), CD22 (57.1%), CD11a (52.4%), and CD58 (33.3%). Using our approach, 60 and 47% of patients had detectable MRD at mid and end induction time points, respectively. Conclusion: We have described a relatively cost effective MRD panel which is applicable to over 90% of patients. We hope that this data would encourage more centers in India and other resource constrained health delivery systems to develop MRD assays

Adult Acute Lymphoblastic Leukemia: Limitations of Intensification of Therapy in a Developing Country

Purpose: Limited data exist on intensifying chemotherapy regimens in the treatment of adult acute lymphoblastic leukemia (ALL) outside the setting of a clinical trial. Materials and Methods: Retrospectively, data from 507 consecutive adults (age ≥ 15 years) with a diagnosis of ALL treated at our center were analyzed. Standard-risk (SR) patients were offered treatment with a modified German Multicenter ALL (GMALL) regimen, whereas high-risk (HR) patients were offered intensification of therapy with hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (HCVAD). Because of resource constraints, a proportion of HR patients opted to receive the same treatment regimen as used for SR patients. Results: There were 344 SR patients (67.8%) and 163 HR patients (32.2%) at diagnosis. Among the HR patients, 53 (32.5%) opted to receive intensification with the HCVAD regimen. The SR cohort showed a superior 5-year event-free survival rate compared with the HR cohort (47.3% v 23.6%, respectively; P < .001). Within the HR subgroup, there was no statistically significant difference in overall survival or event-free survival between patients who received the modified GMALL regimen (n = 59) and patients who received HCVAD (n = 53). Conclusion: Intensified therapy in the HR subset was associated with a significant increase in early treatment-related mortality and cost of treatment. A modified GMALL regimen was found to be cost-effective with clinical outcomes comparable to those achieved with more intensive regimens

Acute myeloid leukaemia: challenges and real world data from India

The management of acute myeloid leukaemia (AML) in India remains a challenge. In a two‐year prospective study at our centre there were 380 newly diagnosed AML (excluding acute promyelocytic leukaemia, AML‐M3) patients. The median age of newly diagnosed patients was 40 years (range: 1–79; 12·3% were &#8804; 15 years, 16·3% were &#8805; 60 years old) and there were 244 (64·2%) males. The median duration of symptoms prior to first presentation at our hospital was 4 weeks (range: 1–52). The median distance from home to hospital was 580 km (range: 6–3200 km). 109 (29%) opted for standard of care and were admitted for induction chemotherapy. Of the 271 that did not take treatment the major reason was lack of financial resources in 219 (81%). There were 27 (24·7%) inductions deaths and of these, 12 (44·5%) were due to multidrug‐resistant gram‐negative bacilli and 12 (44·5%) showed evidence of a fungal infection. The overall survival at 1 year was 70·4% &#177; 10·7%, 55·6% &#177; 6·8% and 42·4% &#177; 15·6% in patients aged &#8804;15 years, 15 ‐ 60 years and &#8805;60 years, respectively. In conclusion, the biggest constraint is the cost of treatment and the absence of a health security net to treat all patients with this diagnosis

RESEARCH ARTICLE Comparison of Newly Diagnosed and Relapsed Patients with Acute Promyelocytic Leukemia Treated with Arsenic Trioxide: Insight into Mechanisms of Resistance

There is limited data on the clinical, cellular and molecular changes in relapsed acute pro-myeloytic leukemia (RAPL) in comparison with newly diagnosed cases (NAPL). We under-took a prospective study to compare NAPL and RAPL patients treated with arsenic trioxide (ATO) based regimens. 98 NAPL and 28 RAPL were enrolled in this study. RAPL patients had a significantly lower WBC count and higher platelet count at diagnosis. IC bleeds was significantly lower in RAPL cases (P=0.022). The ability of malignant promyelocytes to con-centrate ATO intracellularly and their in-vitro IC50 to ATO was not significantly different be-tween the two groups. Targeted NGS revealed PML B2 domain mutations in 4 (15.38%) of the RAPL subset and none were associated with secondary resistance to ATO. A microar-ray GEP revealed 1744 genes were 2 fold and above differentially expressed between the two groups. The most prominent differentially regulated pathways were cell adhesion (n=92), cell survival (n=50), immune regulation (n=74) and stem cell regulation (n=51). Con-sistent with the GEP data, immunophenotyping revealed significantly increased CD34 ex-pression (P=0.001) in RAPL cases and there was in-vitro evidence of significan

Arsenic Trioxide Enhances the NK Cell Cytotoxicity Against Acute Promyelocytic Leukemia While Simultaneously Inhibiting Its Bio-Genesis

Natural killer cells (NK) contribute significantly to eradication of cancer cells, and there is increased interest in strategies to enhance it’s efficacy. Therapeutic agents used in the treatment of cancer can impact the immune system in a quantitative and qualitative manner. In this study, we evaluated the impact of arsenic trioxide (ATO) used in the management of acute promyelocytic leukemia (APL) on NK cell reconstitution and function. In patients with APL treated with single agent ATO, there was a significant delay in the reconstitution of circulating NK cells to reach median normal levels from the time of diagnosis (655 days for NK cells vs 145 and 265 days for T cells and B cells, respectively). In vitro experiments demonstrated that ATO significantly reduced the CD34 hematopoietic stem cell (HSC) differentiation to NK cells. Additional experimental data demonstrate that CD34+ sorted cells when exposed to ATO lead to a significant decrease in the expression of IKZF2, ETS1, and TOX transcription factors involved in NK cell differentiation and maturation. In contrast, exposure of NK cells and leukemic cells to low doses of ATO modulates NK cell receptors and malignant cell ligand profile in a direction that enhances NK cell mediated cytolytic activity. We have demonstrated that NK cytolytic activity toward NB4 cell line when exposed to ATO was significantly higher when compared with controls. We also validated this beneficial effect in a mouse model of APL were the median survival with ATO alone and ATO + NK was 44 days (range: 33–46) vs 54 days (range: 52–75). In conclusion, ATO has a differential quantitative and qualitative effect on NK cell activity. This information can potentially be exploited in the management of leukemia

Comparison of Newly Diagnosed and Relapsed Patients with Acute Promyelocytic Leukemia Treated with Arsenic Trioxide: Insight into Mechanisms of Resistance

<div><p>There is limited data on the clinical, cellular and molecular changes in relapsed acute promyeloytic leukemia (RAPL) in comparison with newly diagnosed cases (NAPL). We undertook a prospective study to compare NAPL and RAPL patients treated with arsenic trioxide (ATO) based regimens. 98 NAPL and 28 RAPL were enrolled in this study. RAPL patients had a significantly lower WBC count and higher platelet count at diagnosis. IC bleeds was significantly lower in RAPL cases (P=0.022). The ability of malignant promyelocytes to concentrate ATO intracellularly and their <i>in-vitro</i> IC50 to ATO was not significantly different between the two groups. Targeted NGS revealed PML B2 domain mutations in 4 (15.38%) of the RAPL subset and none were associated with secondary resistance to ATO. A microarray GEP revealed 1744 genes were 2 fold and above differentially expressed between the two groups. The most prominent differentially regulated pathways were cell adhesion (n=92), cell survival (n=50), immune regulation (n=74) and stem cell regulation (n=51). Consistent with the GEP data, immunophenotyping revealed significantly increased CD34 expression (P=0.001) in RAPL cases and there was in-vitro evidence of significant microenvironment mediated innate resistance (EM-DR) to ATO. Resistance and relapse following treatment with ATO is probably multi-factorial, mutations in PML B2 domain while seen only in RAPL may not be the major clinically relevant cause of subsequent relapses. In RAPL additional factors such as expansion of the leukemia initiating compartment along with EM-DR may contribute significantly to relapse following treatment with ATO based regimens.</p></div

Data_Sheet_1_Arsenic Trioxide Enhances the NK Cell Cytotoxicity Against Acute Promyelocytic Leukemia While Simultaneously Inhibiting Its Bio-Genesis.docx

<p>Natural killer cells (NK) contribute significantly to eradication of cancer cells, and there is increased interest in strategies to enhance it’s efficacy. Therapeutic agents used in the treatment of cancer can impact the immune system in a quantitative and qualitative manner. In this study, we evaluated the impact of arsenic trioxide (ATO) used in the management of acute promyelocytic leukemia (APL) on NK cell reconstitution and function. In patients with APL treated with single agent ATO, there was a significant delay in the reconstitution of circulating NK cells to reach median normal levels from the time of diagnosis (655 days for NK cells vs 145 and 265 days for T cells and B cells, respectively). In vitro experiments demonstrated that ATO significantly reduced the CD34 hematopoietic stem cell (HSC) differentiation to NK cells. Additional experimental data demonstrate that CD34⁺ sorted cells when exposed to ATO lead to a significant decrease in the expression of IKZF2, ETS1, and TOX transcription factors involved in NK cell differentiation and maturation. In contrast, exposure of NK cells and leukemic cells to low doses of ATO modulates NK cell receptors and malignant cell ligand profile in a direction that enhances NK cell mediated cytolytic activity. We have demonstrated that NK cytolytic activity toward NB4 cell line when exposed to ATO was significantly higher when compared with controls. We also validated this beneficial effect in a mouse model of APL were the median survival with ATO alone and ATO + NK was 44 days (range: 33–46) vs 54 days (range: 52–75). In conclusion, ATO has a differential quantitative and qualitative effect on NK cell activity. This information can potentially be exploited in the management of leukemia.</p