Publications by authors named "Sen Mui Tan"

9 Publications

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A variant e13a3 BCR-ABL1 fusion transcript in refractory adult B-cell acute lymphoblastic leukemia achieving complete remission with CAR-Tcell therapy.

Cancer Genet 2021 Jan 6;250-251:20-24. Epub 2020 Nov 6.

Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia. Electronic address:

Acute lymphoblastic leukemia (ALL) cases with e13a3 fusion transcripts are extremely rare. We report a 24-year-old male with Ph-positive (Ph+) ALL with an aberrant e13a3 fusion transcript treated with CD19-specific chimeric antigen receptor T-cell (CAR-T) therapy. He developed refractory disease post-chemotherapy induction, andreceived allogeneic hematopoietic stem cell transplantation (allo-HSCT) after salvage with imatinib in combination with chemotherapy regimen. Unfortunately, the patient relapsed after +90 days post-transplant. He was consented to CAR-T therapy trial and achieved complete remission, highlighting the efficacy of CAR-T treatment in relapsed-refractory B-ALL irrespective of the underlying genetic drivers in leukemia cells .
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January 2021

Effect of Recombinant Zoster Vaccine on Incidence of Herpes Zoster After Autologous Stem Cell Transplantation: A Randomized Clinical Trial.

JAMA 2019 07;322(2):123-133

Duke University Medical Center, Durham, North Carolina.

Importance: Herpes zoster, a frequent complication following autologous hematopoietic stem cell transplantation (HSCT), is associated with significant morbidity. A nonlive adjuvanted recombinant zoster vaccine has been developed to prevent posttransplantation zoster.

Objective: To assess the efficacy and adverse event profile of the recombinant zoster vaccine in immunocompromised autologous HSCT recipients.

Design, Setting, And Participants: Phase 3, randomized, observer-blinded study conducted in 167 centers in 28 countries between July 13, 2012, and February 1, 2017, among 1846 patients aged 18 years or older who had undergone recent autologous HSCT.

Interventions: Participants were randomized to receive 2 doses of either recombinant zoster vaccine (n = 922) or placebo (n = 924) administered into the deltoid muscle; the first dose was given 50 to 70 days after transplantation and the second dose 1 to 2 months thereafter.

Main Outcomes And Measures: The primary end point was occurrence of confirmed herpes zoster cases.

Results: Among 1846 autologous HSCT recipients (mean age, 55 years; 688 [37%] women) who received 1 vaccine or placebo dose, 1735 (94%) received a second dose and 1366 (74%) completed the study. During the 21-month median follow-up, at least 1 herpes zoster episode was confirmed in 49 vaccine and 135 placebo recipients (incidence, 30 and 94 per 1000 person-years, respectively), an incidence rate ratio (IRR) of 0.32 (95% CI, 0.22-0.44; P < .001), equivalent to 68.2% vaccine efficacy. Of 8 secondary end points, 3 showed significant reductions in incidence of postherpetic neuralgia (vaccine, n=1; placebo, n=9; IRR, 0.1; 95% CI, 0.00-0.78; P = .02) and of other prespecified herpes zoster-related complications (vaccine, n=3; placebo, n=13; IRR, 0.22; 95% CI, 0.04-0.81; P = .02) and in duration of severe worst herpes zoster-associated pain (vaccine, 892.0 days; placebo, 6275.0 days; hazard ratio, 0.62; 95% CI, 0.42-0.89; P = .01). Five secondary objectives were descriptive. Injection site reactions were recorded in 86% of vaccine and 10% of placebo recipients, of which pain was the most common, occurring in 84% of vaccine recipients (grade 3: 11%). Unsolicited and serious adverse events, potentially immune-mediated diseases, and underlying disease relapses were similar between groups at all time points.

Conclusions And Relevance: Among adults who had undergone autologous HSCT, a 2-dose course of recombinant zoster vaccine compared with placebo significantly reduced the incidence of herpes zoster over a median follow-up of 21 months.

Trial Registration: Identifier: NCT01610414.
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July 2019

The epidemiology and clinical characteristics of myeloproliferative neoplasms in Malaysia.

Exp Hematol Oncol 2018 17;7:31. Epub 2018 Dec 17.

Department of Haematology, Sunway Medical Centre, Kuala Lumpur, Malaysia.

Background: The evolution of molecular studies in myeloproliferative neoplasms (MPN) has enlightened us the understanding of this complex disease consisting of polycythaemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The epidemiology is well described in the western world but not in Asian countries like Malaysia.

Materials And Methods: This retrospective national registry of MPN was conducted from year 2009 to 2015 in Malaysia.

Results: A total of 1010 patients were registered over a period of 5 years. The mean age was 54 years with male predominance. The ethnic distribution revealed that Chinese had a relatively high weighted incidence proportion (43.2%), followed by Indian (23.8%), Malay (15.8%) and other ethnic groups (17.2%). The types of MPN reported were 40.4% of ET (n = 408), 38.1% of PV (n = 385), 9.2% of PMF (n = 93), 3.1% of hypereosinophilic syndrome (HES) (n = 31) and 7.9% of unclassifiable MPN (MPN-U) (n = 80). Splenomegaly was only palpable clinically in 32.2% of patients. The positive JAK2 V617F mutation was present in 644 patients with 46.6% in PV, 36.0% in ET, 9.0% in PMF, and 7.4% in MPN-U, and had significantly lower haemoglobin (p < 0.001), haematocrit (p < 0.001) and white blood cells (WBC) (p < 0.001) than those with negative mutation. Significant differences in platelet and WBC count were detected in ethnic groups and MPN sub-types. There were more arterial thrombosis events seen in those with JAK2 V617F mutation as compared to venous thrombosis events (23.1% vs 4.4%). The bleeding rate was only 6.6%. Among the risk factors, previous thrombosis, old age (≥ 60 years) and hypertension were significantly correlated to positive JAK2 V617F mutation. The arterial thrombosis event is associated with higher presenting HB, HCT and PLT while the bleeding event is associated with lower presenting HB, HCT but higher PLT. The presence of JAK2 V617F mutation is associated with higher risk of arterial thrombosis.

Conclusion: Chinese ethnicity is associated with higher rates of MPN. The history of thrombosis, age ≥ 60 years and hypertension are risk factors that can be correlated to JAK2 V617F mutation. This study is instrumental for policy makers to ensure preventive strategies can be implemented in future.
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December 2018

A randomized double blind control trial comparing filgrastim and pegfilgrastim in cyclophosphamide peripheral blood hematopoietic stem cell mobilization.

Transfus Apher Sci 2015 Oct 30;53(2):196-204. Epub 2015 Mar 30.

Department of Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Sarawak, Malaysia; Department of Hematology, Ampang Hospital, Selangor, Malaysia.

There are few randomized trials comparing filgrastim and pegfilgrastim in peripheral blood stem cell mobilization (PBSCM). None of the trials studied the effects of the timing of pegfilgrastim administration on the outcomes of mobilization. We conducted a randomized triple blind control trial comparing the outcomes of filgrastim 5 µg/kg daily from day 3 onwards, 'early' pegfilgrastim 6 mg on day 3 and 'delayed' pegfilgrastim 6 mg on day 7 in cyclophosphamide PBSCM in patients with no previous history of mobilization. Peripheral blood (PB) CD34+ cell count was checked on day 8 and day 11 onward. Apheresis was started when PB CD34+ ≥ 10/µl from day 11 onward. The primary outcome was the successful mobilization rate, defined as cumulative collection of ≥ 2 × 10(6)/kg CD34+ cells in three or less apheresis. The secondary outcomes were the day of neutrophil and platelet engraftment post transplantation. There were 156 patients randomized and 134 patients' data analyzed. Pegfilgrastim 6 mg day 7 produced highest percentage of successful mobilization, 34 out of 48 (70.8%) analyzed patients, followed by daily filgrastim, 28 out of 44 (63.6%) and day 3 pegfilgrastim, 20 out of 42 (47.6%) (p = 0.075). Pegfilgrastim day 7 and daily filgrastim reported 1.48 (p = 0.014) and 1.49 (p = 0.013) times higher successful mobilization rate respectively as compared to pegfilgrastim day 3 after adjusting for disease, gender and exposure to myelotoxic agent. Multiple myeloma patients were three times more likely to achieve successful mobilization as compared to acute leukemia or lymphoma patients. Pegfilgrastim avoided the overshoot of white cells compared to filgrastim. There was no difference in the duration of both white cells and platelet recovery post transplantation between the three interventional arms.
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October 2015

Stimulating surface molecules, Th1-polarizing cytokines, proven trafficking--a new protocol for the generation of clinical-grade dendritic cells.

Cytotherapy 2013 Apr;15(4):492-506

Medizinische Klinik and Poliklinik II, University Hospital Wuerzburg, Wuerzburg, Germany.

Background Aims: Dendritic cells (DC) have been vigorously investigated as an immunological basis for therapeutic vaccination against cancer and infections, even among patients after allogeneic stem cell transplantation.

Methods: Effective induction of cell-mediated immunity strongly depends on the ability of DC to (i) migrate to the draining lymphoid organs mediated by chemokine receptors, (ii) prime T cells through high expression of costimulatory molecules and major histocompatibility complexes and (iii) secret Th1-polarizing cytokines such as Interleukin-12 (IL-12). However, there is no protocol to generate fully matured and functional DC according to methodical requirements of current good manufacturing practice (CGMP) guidelines.

Results: We established a protocol conforming to CGMP standards that permits the generation of fully matured and functional DC on the basis of cell culture in adherence bags with the use of serum-free media with a maturation cocktail, containing tumor necrosis factor-alpha/Interferon-alpha/polyinosinic:polycytidylic acid. Our DC superiorly display three critical features for an effective induction of cell-mediated immunity without evidence of exhaustion, along with its ability to prime infectious or tumor-specific T cells in a short-term cell culture.

Conclusions: Our newly developed protocol offers an attractive method to produce fully matured Th1-polarizing DC with proven migratory and stimulatory capacity for any clinical application according to CGMP standards.
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April 2013

The Outcome of HyperCVAD Combined with Alemtuzumab for the Treatment of Aggressive T-Cell and NK-Cell Neoplasms.

Indian J Hematol Blood Transfus 2011 Sep 5;27(3):136-45. Epub 2011 Jun 5.

We report our experience in using six cycles of hyperCVAD in combination with alemtuzumab for the treatment of aggressive T-cell and NK/T-cell neoplasms. Seven females and six males with the median age of 41 (range 18-60) diagnosed with T-cell acute lymphoblastic lymphoma and peripheral T-cell and NK/T-cell neoplasms (n(PTCL) = 6, n(T-cell ALL) = 3, n(NK/T-cell neoplasms) = 4) from 2006 to 2008 were treated with alemtuzumab-hyperCVAD regimen. A total of nine patients (69%) responded to the regimen, with seven achieved complete remission and two achieved partial remission. The median progression free survival and overall survival duration among the responders with complete remission were 12.9 and 24.9 months respectively. The incidence of relapse among the responders was 44% and the overall survival rate was 23%. Only four (31%) patients completed the six cycles of alemtuzumab-hyperCVAD. Others were stopped earlier due to progressive disease (n = 2), cytomegalovirus (CMV) reactivation and/or disease (n = 3), death not due to disease (n = 2), and patient's refusal to continue alemtuzumab (n = 2). The incidence of death not due to disease, CMV reactivation and recurrent CMV reactivation were 50, 50 and 17%, respectively. This study shows that alemtuzumab in combination with hyperCVAD regimen is a feasible regimen but with high toxicity. The toxicity might be reduced with the incorporation of filgrastim and use of valganciclovir as CMV prophylaxis.
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September 2011

Uptake of antigens from modified vaccinia Ankara virus-infected leukocytes enhances the immunostimulatory capacity of dendritic cells.

Cytotherapy 2011 Jul 20;13(6):739-52. Epub 2011 Jan 20.

Medical Clinic and Policlinic II, Department of Hematology, Julius Maximilians University of Würzburg, Würzburg, Germany.

Background Aims: Modified vaccinia Ankara (MVA) is a promising vaccine vector for infectious diseases and malignancies. It is fundamental to ascertain its tropism in human leukocyte populations and immunostimulatory mechanisms for application in immunotherapy.

Methods: Human peripheral blood mononuclear cells (PBMC) and leukocyte subpopulations [monocyte-derived dendritic cells (DC), monocytes and B cells] were infected with MVA in order to evaluate their infection rate, changes in surface markers, cytokine expression and apoptosis.

Results: Monocytes, DC and B cells were most susceptible to MVA infection, followed by natural killer (NK) cells. Monocytes were activated strongly, with upregulation of co-stimulatory molecules, major histocompatibility complex (MHC) molecules and chemokine (C-C motif) receptor (CCR7), while immature DC showed partial activation and B cells were inhibited. Furthermore, expression of chemokine (C-X-C motif) ligand (CXCL10), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-12p70 was enhanced but IL-1β and IL-10 were stable or even downregulated. MVA induced a high apoptosis rate of antigen-presenting cells (APC). Nevertheless, incubation of MVA-infected leukocytes with uninfected immature DC (iDC) led to complete maturation of the DC. Subsequently, the matured DC were able to stimulate cytomegalovirus (CMV)-immediate early protein (IE1)-specific T cells.

Conclusions: MVA induces a T-helper (Th)-1-polarizing cytokine expression in APC. Furthermore, incubation of MVA-infected leukocytes with uninfected iDC leads to complete maturation of the DC and may be the basis for cross-presentation of MVA-encoded antigens. Thus this approach seems to be an ideal model for further studies with MVA-encoded viral antigens regarding immunotherapy and vaccination strategies.
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July 2011

Amplification of BCR-ABL and t(3;21) in a patient with blast crisis of chronic myelogenous leukemia.

Cancer Genet Cytogenet 2008 Jan;180(1):60-4

Department of Hematology, Hospital Ampang, Jalan Megah Utara, Pandan Mewah, 68000 Ampang, Selangor, Malaysia.

The Philadelphia (Ph) chromosome, or t(9;22), is the hallmark of chronic myelogenous leukemia (CML). It results in juxtaposition of the 5' part of the BCR gene on chromosome 22 to the 3' part of the ABL1 gene (previously ABL) on chromosome 9. CML is clinically characterized by three distinct phases: chronic, accelerated, and blast phase. Blast crisis is characterized by the rapid expansion of a population of differentiation arrested blast cells (myeloid or lymphoid cells population), with secondary chromosomal abnormalities present. We report a case of myeloid blast crisis of CML resistant to imatinib mesylate and chemotherapy. By use of cytogenetic, fluorescence in situ hybridization, and comparative genomic hybridization methods, we identified a cluster of BCR-ABL amplification on inverted duplication of the Ph chromosome with t(3;21)(q26;q22) and increased genomic levels of the RUNX1 gene (previously AML1). The t(3;21)(q26;q22) is a recurrent chromosomal abnormality in some cases of CML blast phase and in treatment-related myelodysplastic syndrome and acute myeloid leukemia. Amplification or copy number increase of RUNX1 has been reported in childhood acute lymphoblastic leukemia. Our study indicated that the progenitor of CML was BCR-ABL dependent through the amplification of Ph chromosome as a mechanism of resistance to imatinib therapy. The coexistence of BCR-ABL and t(3;21)(q26;q22) with RUNX1 rearrangement might play a pivotal role in the CML blast transformation.
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January 2008