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Background and Objectives: Patients undergoing induction/reinduction chemotherapy for haematologic malignancies (HM) are at risk for invasive fungal infections (IFIs). In 2015, Duke University Hospital (DUH) implemented a new standardised fungal prophylaxis protocol for adult patients undergoing induction chemotherapy for acute lymphocytic leukaemia, acute myelocytic leukaemia and myelodysplastic syndrome. This study assessed the impact of protocol implementation on (1) use of antifungal prophylaxis, throughout the at‐risk period and (2) patient outcomes such as IFI and mortality. Methods: Retrospective, observational study of adult HM patients admitted to DUH for induction/reinduction chemotherapy pre‐ (7/1/2013–12/31/2014) and post‐ (1/1/2015–10/31/2016) implementation of standardised antifungal prophylaxis protocol (which recommended posaconazole as the first‐line agent). Patients were followed for up to 100 days after initiation of induction chemotherapy to evaluate use of antifungal prophylaxis and patient outcomes. Results: 218 patients with haematologic malignancies were included (90 pre, 128 post). Use of antifungal prophylaxis increased from 81.1% (pre) to 97.7% (post) (p <.0001). Overall, 71% received posaconazole as initial antifungal prophylaxis (64.4% pre, 75.7% post). Approximately one‐fourth of patients (25.6%, pre vs 26.6%, post) developed an IFI (proven/probable or possible using modified EORTC definitions) (p =.868); 100‐day mortality remained stable (18.9% pre vs 18.8% post, respectively, p =.979). Lack of antifungal prophylaxis and older age (≥60 years) were associated with higher risk of IFI. Conclusion: Implementation of a standardised protocol with posaconazole as the primary agent was associated with increased use of antifungal prophylaxis among patients undergoing induction/reinduction chemotherapy for haematologic malignancies in our hospital. Lack of antifungal prophylaxis was an independent predictor of IFIs, underscoring the importance of prophylaxis in this at‐risk population. [ABSTRACT FROM AUTHOR]

Background: Acute myeloid leukemia (AML) is fatal in elderly patients who are unfit for standard induction chemotherapy. The objective of this study was to evaluate the survival benefit of administering sapacitabine, an oral nucleoside analogue, in alternating cycles with decitabine, a low‐intensity therapy, to elderly patients with newly diagnosed AML. Methods: This randomized, open‐label, phase 3 study (SEAMLESS) was conducted at 87 sites in 11 countries. Patients aged ≥70 years who were not candidates for or chose not to receive standard induction chemotherapy were randomized 1:1 to arm A (decitabine in alternating cycles with sapacitabine) received 1‐hour intravenous infusions of decitabine 20 mg/m2 once daily for 5 consecutive days every 8 weeks (first cycle and subsequent odd cycles) and sapacitabine 300 mg twice daily on 3 consecutive days per week for 2 weeks every 8 weeks (second cycle and subsequent even cycles) or to control arm C who received 1‐hour infusions of decitabine 20 mg/m2 once daily for 5 consecutive days every 4 weeks. Prior hypomethylating agent therapy for preexisting myelodysplastic syndromes or myeloproliferative neoplasms was an exclusion criterion. Randomization was stratified by antecedent myelodysplastic syndromes or myeloproliferative neoplasms, white blood cell count (<10 × 109/L and ≥10 × 109/L), and bone marrow blast percentage (≥50% vs <50%). The primary end point was overall survival (OS). Secondary end points were the rates of complete remission (CR), CR with incomplete platelet count recovery, partial remission, hematologic improvement, and stable disease along with the corresponding durations, transfusion requirements, number of hospitalized days, and 1‐year survival. The trial is registered at ClinicalTrials.gov (NCT01303796). Results: Between October 2011 and December 2014, 482 patients were enrolled and randomized to receive decitabine administered in alternating cycles with sapacitabine (study arm, n = 241) or decitabine monotherapy (control arm, n = 241). The median OS was 5.9 months on the study arm versus 5.7 months on the control arm (P =.8902). The CR rate was 16.6% on the study arm and 10.8% on the control arm (P =.1468). In patients with white blood cell counts <10 × 109/L (n = 321), the median OS was higher on the study arm versus the control arm (8.0 vs 5.8 months; P =.145), as was the CR rate (21.5% vs 8.6%; P =.0017). Conclusions: The regimen of decitabine administered in alternating cycles with sapacitabine was active but did not significantly improve OS compared with decitabine monotherapy. Subgroup analyses suggest that patients with baseline white blood cell counts <10 × 109/L might benefit from decitabine alternating with sapacitabine, with an improved CR rate and the convenience of an oral drug. These findings should be prospectively confirmed. The regimen of decitabine administered in alternating cycles with sapacitabine is active but does not significantly improve overall survival compared with decitabine monotherapy. Subgroup analyses suggest that patients with baseline white blood cell counts <10 × 109/L might benefit from decitabine alternating with sapacitabine, which has an improved complete remission rate and the convenience of an oral drug; these findings should be prospectively confirmed. [ABSTRACT FROM AUTHOR]

Background: Acute myeloid leukemia (AML) is a heterogenous malignancy driven by genetic and epigenetic factors. Inhibition of bromodomain and extraterminal (BET) proteins, epigenetic readers that play pivotal roles in the regulation of genes relevant to cancer pathogenesis, constitutes a novel AML treatment approach. Methods: In this first‐in‐human study of the pan‐BET inhibitor mivebresib as monotherapy (MIV‐mono) or in combination with venetoclax (MIV‐Ven), the safety profile, efficacy, and pharmacodynamics of mivebresib were determined in patients with relapsed/refractory AML (ClinicalTrials.gov identifier NCT02391480). Mivebresib was administered at 3 monotherapy dose levels (1.5, 2.0, or 2.5 mg) or in combination with venetoclax (400 or 800 mg). Results: Forty‐four patients started treatment: of 19 who started MIV‐mono, 5 went on to receive MIV‐Ven combination therapy after disease progression and a washout period. Twenty‐five patients started MIV‐Ven, resulting in a total of 30 patients treated with the combination. The most common mivebresib‐related treatment‐emergent adverse events were dysgeusia (74%), decreased appetite (42%), and diarrhea (42%) in the MIV‐mono group and decreased appetite (44%), vomiting (44%), and nausea (40%) in the MIV‐Ven group. Serious adverse events occurred in 14 patients (74%) who received MIV‐mono and in 22 patients (88%) who received MIV‐Ven. In the MIV‐mono group, responses were complete remission with incomplete blood count recovery in 1 patient and resistant disease in 15 patients. In the MIV‐Ven group, responses were complete remission in 2 patients, partial remission in 2 patients, morphologic leukemia‐free state in 2 patients, resistant disease in 12 patients, and aplasia in 1 patient. The pharmacodynamic effects of mivebresib were proportional to dose and drug exposure. Conclusions: Mivebresib was tolerated and showed antileukemic effects as monotherapy and in combination with venetoclax in patients with relapsed/refractory AML. Lay Summary: Mivebresib is a novel drug that influences the way cancer cells read genetic information. Mivebresib was tested together with venetoclax in patients with acute myeloid leukemia after standard medicines failed and the disease returned, or when standard medicine was unavailable. Adverse effects were described for different drug doses, and the dose that is tolerable was determined. In some patients, their leukemia improved for some time. More studies are necessary to determine whether mivebresib can be used to treat acute myeloid leukemia. Mivebresib is tolerable and produces antileukemic effects as monotherapy and when combined with venetoclax in patients who have relapsed/refractory acute myeloid leukemia. Mivebresib also demonstrates a statistically significant dose‐dependent correlation between biomarker modulation and drug exposure. [ABSTRACT FROM AUTHOR]

The article offers information on a study related to dose-intense chemoimmunotherapy and radioimmunotherapy in high-risk diffuse large B-cell lymphoma and mantle cell lymphoma. It notes the three phases of treatment regimen induction 1, induction 2, and consolidation phase. It mentions the that this therapy is effective in patients with high-risk non-Hodgkin lymphoma (NHL) but is toxic.

Background: Outcomes for patients with relapsed or refractory acute myeloid leukemia (AML) are poor. Guadecitabine, a next-generation hypomethylating agent, could be useful in treating such patients.Methods: In this multicenter, open-label, phase 2 dose-expansion study, AML patients from 10 North American medical centers were first randomized (1:1) to receive subcutaneous guadecitabine at 60 or 90 mg/m2 on 5 consecutive days in each 28-day cycle (5-day regimen). Subsequently, another cohort was treated for 10 days with 60 mg/m2 (10-day regimen).Results: Between June 15, 2012, and August 19, 2013, 108 patients with previously treated AML consented to enroll in the study, and 103 of these patients were treated; 5 patients did not receive the study treatment. A total of 103 patients were included in the safety and efficacy analyses (24 and 26 patients who were randomly assigned to 60 and 90 mg/m2 /d, respectively [5-day regimen] and 53 patients who were assigned to 60 mg/m2 /d [10-day regimen]). The 90 mg/m2 dose showed no benefit in clinical outcomes in comparison with 60 mg/m2 in the randomized cohort. Composite complete response (CRc) and complete response (CR) rates were higher with the 10-day regimen versus the 5-day regimen (CRc, 30.2% vs 16.0%; P = .1061; CR, 18.9% vs 8%; P = .15). Adverse events (grade ≥ 3) were mainly hematologic, with a higher incidence on the 10-day regimen. Early all-cause mortality was low and similar between regimens. Twenty patients (8 on the 5-day regimen and 12 on the 10-day regimen) were bridged to hematopoietic cell transplantation.Conclusions: Guadecitabine has promising clinical activity and an acceptable safety profile and thus warrants further development in this population. Cancer 2018;124:325-34. © 2017 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. [ABSTRACT FROM AUTHOR]

We retrospectively studied 340 fit patients with multiple myeloma (MM) who underwent autologous stem cell transplantation (ASCT). We hypothesized that progression-free survival (PFS) of older patients was non-inferior to that of younger patients after ASCT. Our null hypothesis was that the PFS hazard ratio (HR) for a 5-year increase in age was ≥1.05; the alternative (non-inferiority) hypothesis was that the HR was ≤1. The observed HR was 0.94 (95% confidence interval [CI] 0.86-1.03); since the CI upper bound was <1.05, we reject the null hypothesis and conclude that PFS in older patients was at least as good as in younger patients. We cannot reject an analogous null hypothesis for overall survival (HR 1.06 [95% CI 0.94-1.19]), since the CI upper bound >1.05. Toxicity was similar across ages and transplant-related mortality was minimal. 28% of subjects <65 versus 45% of those ≥65 received maintenance therapy. In summary, ASCT prolongs PFS equally well in older vs. younger adults. Although we cannot exclude maintenance as a confounder, these data support ASCT for fit seniors with MM. [ABSTRACT FROM AUTHOR]

Deregulation of histone deacetylase ( HDAC) is important in the pathogenesis of follicular lymphoma ( FL) and diffuse large B-cell lymphoma ( DLBCL). Mocetinostat, an isotype-selective HDAC inhibitor, induces accumulation of acetylated histones, cell cycle arrest and apoptosis in several cancers. This phase 2 study evaluated mocetinostat in patients with relapsed/refractory (R/R) DLBCL and FL. Seventy-two patients received mocetinostat (starting doses: 70-110 mg TIW, 4-week cycles). The best overall response rate (95% CI) was 18·9% (7·2, 32·2) for the DLBCL cohort ( n = 41), and 11·5% (1·7, 20·7) for the FL cohort ( n = 31). Responses were durable (≥90 days in 7 of 10 responses). Overall, 54·1% and 73·1% of patients derived clinical benefit (response or stable disease) from mocetinostat in the DLBCL and FL cohorts, respectively. Progression-free survival ranged from 1·8 to 22·8 months and 11·8 to 26·3 months in responders with DLBCL and FL, respectively. The most frequent treatment-related adverse events were fatigue (75·0%), nausea (69·4%) and diarrhoea (61·1%). Although mocetinostat had limited single-agent activity in R/R DLBCL and FL, patients with clinical benefit had long-term disease control. The safety profile was acceptable. This drug class warrants further investigation, including identifying patients more likely to respond to this agent, or in combination with other agents. [ABSTRACT FROM AUTHOR]

Background: Allogeneic hematopoietic cell transplantation (HCT) offers curative potential to a number of older patients with acute myeloid leukemia (AML) in their first complete remission. However, there are limited data in the literature concerning post-HCT outcomes for older patients in their second complete remission (CR2).Methods: The purpose of the current study was to retrospectively investigate within the Center for International Blood and Marrow Transplant Research database parameters influencing posttransplant outcomes for patients 60 years of age or older undergoing HCT for AML in CR2.Results: In total, 196 patients from 78 centers were identified; the median age was 64 years (range, 60-78 years). Seventy-one percent had a Karnofsky performance status ≥ 90 at the time of HCT. Reduced-intensity conditioning regimens were used in 159 patients (81%). A univariate analysis demonstrated a 3-year overall survival (OS) rate of 42% (95% confidence interval [CI], 35%-49%), a leukemia-free survival rate of 37% (95% CI, 30%-44%), a cumulative incidence of nonrelapse mortality of 25% (95% CI, 19%-32%), and a cumulative incidence of relapse (CIR) of 38% (95% CI, 31%-45%). A multivariate analysis demonstrated that cytogenetic risk was the only independent risk factor for OS (P = .023) with a hazard ratio (HR) of 1.14 (95% CI, 0.59-2.19) for intermediate-risk cytogenetics and an HR of 2.32 (95% CI, 1.05-5.14) for unfavorable-risk cytogenetics. For CIR, cytogenetic risk was also the only independent prognostic factor (P = .01) with an HR of 1.10 (95% CI, 0.47-2.56) for intermediate-risk cytogenetics and an HR of 2.98 (95% CI, 1.11-8.00) for unfavorable-risk cytogenetics.Conclusions: Allogeneic HCT is a curative treatment option for older patients with AML in CR2, particularly for those with favorable or intermediate cytogenetic risk. Cancer 2017;123:2035-2042. © 2017 American Cancer Society. [ABSTRACT FROM AUTHOR]

Myelodysplastic syndromes ( MDS) are clonal hematopoietic stem cell disorders characterized by abnormal cellular differentiation and maturation with variable progression to acute leukemia. Over the last decade, scientific discoveries have unraveled specific pathways involved in the complex pathophysiology of MDS. Prominent examples include aberrations in cytokines and their signaling pathways (such as tumor necrosis factor-alpha, interferon-gamma, SMAD proteins), mutations in genes encoding the RNA splicing machinery ( SF3B1, SRSF2, ZRSR2, and U2 AF1 genes), mutations in genes disrupting the epigenetic machinery ( TET2, DNMT3A, DNMT3B, EZH2, ASXL1). In addition, abnormalities in regulatory T-cell dynamics and atypical interactions between the bone marrow microenvironment, stroma and progenitor cells, and abnormal maintenance of telomeres are also notable contributors to the complex pathogenesis of MDS. These pathways represent potential targets for novel therapies. Specific therapies include drugs targeting aberrant DNA methylation and chromatin remodeling, modulating/activating the immune system to enhance tumor-specific cellular immune responses and reduce anomalous cytokine signaling, and blocking abnormal interaction between hematopoietic progenitors and stromal cells. [ABSTRACT FROM AUTHOR]

High-dose cyclophosphamide (Cy) is frequently employed for peripheral blood mobilization of hematopoietic stem cells before high-dose chemotherapy with autologous stem cell transplantation (ASCT) in multiple myeloma (MM). The benefit of mobilization with Cy over filgrastim (granulocyte colony-stimulating factor; G-CSF) alone is unclear. Between 2000 and 2008, 167 patients with newly diagnosed MM underwent single ASCT after melphalan conditioning at our institution. Seventy-three patients were mobilized with G-CSF alone, and 94 patients with Cy plus G-CSF (Cy+G-CSF). We retrospectively analyzed Cy's impact on both toxicity and efficacy. Mobilization efficiency was augmented by Cy; a mean total of 12 versus 5.8 × 106 CD34+ cells/kg were collected from patients mobilized with Cy+G-CSF versus G-CSF, respectively, ( P < 0.01), over a mean of 1.6 versus 2.2 days of peripheral blood apheresis (p = 0.001). Mobilization-related toxicity was also, however, augmented by Cy; 14% of Cy+G-CSF patients were hospitalized because of complications versus none receiving G-CSF ( P < 0.0001). Toxicity, including death, related to ASCT was similar between cohorts. Regarding long-term outcomes, multivariate analysis revealed no difference for Cy+G-CSF versus G-CSF (hazard ratio 0.8 for event-free survival [95% confidence interval {CI} 0.57-1.25] and 0.96 for overall survival [95% CI 0.61-1.54]). In summary, we show that mobilization with Cy increases toxicity without positively impacting long-term outcomes in MM. Our findings place into question Cy's benefit as a routine component of stem cell mobilization regimens in MM. Randomized trials are needed to elucidate the risks and benefits of Cy more definitively. J. Clin. Apheresis 30:176-182, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: Peripheral blood stem cell mobilization using growth factors is a common method of stem cell collection for transplantation, however, little is reported concerning safety of continued growth factor delivery in exceptional responders with very high white blood cell (WBC) counts in preparation for pheresis. We performed a retrospective study of the safety of growth factor delivery for leukapheresis in those with WBC counts greater than 60,000/µl. Methods: Allogeneic donors received 5 days of granulocyte colony-stimulating factor (G-CSF) at a daily dose of 10 or 16 µg/kg. Autologous donors received G-CSF 10 µg/kg/day +/− chemotherapy until peripheral blood CD34+count reached 10/µl. Granulocyte donors received 300 µg dose of G-CSF the day prior to donation. Results: Out of 3,037 leukapheresis collections from 1998 to 2005, we identified 303 collections from 204 donors or patients who had a WBC > 60,000/µl. WBC counts were ≥100,000/µl in seven of these subjects. If inadequate stem cell dose was obtained with pheresis with WBC counts this high, patients had growth factor dosing decreased 50% but still received a dose till stem cell collection was completed. Of the 204 subjects, 122 were patients and 82 were donors. These 204 donors/patients had no serious adverse events reported other than the common reports of myalgia, bone pain, and headache associated with administration of growth factors. Pain levels ranged from mild to severe and usually were managed by over the counter analgesics. Conclusions: Continuing ½ the dose of neupogen to complete the pheresis process appears safe in subjects with very high white blood counts. J. Clin. Apheresis 30:28-31, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

To improve long-term outcomes for Burkitt leukaemia/lymphoma ( BL) or aggressive lymphomas in adults, we assessed the benefit of adding rituximab and filgrastim support to a dose-dense modified chemotherapy regimen from the Cancer and Leukemia Group B ( CALGB) 9251 trial. One hundred and five patients (aged 19-79 years) were enrolled; 27% were >60 years old; 47% had high or high-intermediate risk by International Prognostic Index ( IPI) criteria. Common severe toxicities included stomatitis/upper gastrointestinal toxicity (69%), renal insufficiency (10%), neurological events (25%) and pulmonary events (18%). Seven died from treatment-related causes (one central nervous system bleed, four infections, two respiratory failure); five were >60 years old. Results in this adult population are encouraging as complete response ( CR) was observed in 83% and 4-year event-free ( EFS) and overall survivals ( OS) were 74% and 78%, respectively. Results compare favourably to our prior chemotherapy alone study ( CALGB 9251) but despite this, high-risk patients still had worse outcomes. In conclusion, short duration, intensive chemo-immunotherapy is feasible and should be considered in adults with BL as it results in high remission rates and durable remissions. [ABSTRACT FROM AUTHOR]

Pre-existing central nervous system ( CNS) involvement may influence referral for autologous haematopoietic cell transplantation ( AHCT) for patients with non-Hodgkin lymphoma ( NHL). The outcomes of 151 adult patients with NHL with prior secondary CNS involvement ( CNS+) receiving an AHCT were compared to 4688 patients without prior CNS lymphoma ( CNS−). There were significant baseline differences between the cohorts. CNS+ patients were more likely to be younger, have lower performance scores, higher age-adjusted international prognostic index scores, more advanced disease stage at diagnosis, more aggressive histology, more sites of extranodal disease, and a shorter interval between diagnosis and AHCT. However, no statistically significant differences were identified between the two groups by analysis of progression-free survival ( PFS) and overall survival ( OS) at 5 years. A matched pair comparison of the CNS+ group with a subset of CNS− patients matched on propensity score also showed no differences in outcomes. Patients with active CNS lymphoma at the time of AHCT ( n = 55) had a higher relapse rate and diminished PFS and OS compared with patients whose CNS lymphoma was in remission ( n = 96) at the time of AHCT. CNS+ patients can achieve excellent long-term outcomes with AHCT. Active CNS lymphoma at transplant confers a worse prognosis. [ABSTRACT FROM AUTHOR]

Elacytarabine is a novel cytotoxic nucleoside analogue, independent of nucleoside transporters (e.g. human Equilibrative Nucleoside Transporter 1 [ hENT1]) for cell uptake, and mechanisms of action similar to those of cytarabine. This Phase II study assessed the efficacy and safety of elacytarabine in patients with advanced stage acute myeloid leukaemia ( AML). Patients received 2000 mg/m2 per d continuously i.v. during days 1-5 every 3 weeks. Patients were matched by six risk factors with historical controls; remission rate (assessed after 1 or 2 cycles) and 6-month survival were compared. Sixty-one patients, median age 58 years, were enrolled; 52% had five or six risk factors. The remission rate was 18% (95% confidence interval: 9-30%) vs. 4% in controls ( P < 0·0001), 6-month survival rate was 43%, median overall survival was 5·3 months (vs. 1·5 months); 10 patients (16%) were referred for stem cell transplantation after treatment. Side effects were predictable and manageable. The most common grade 3/4 non-haematological adverse events were febrile neutropenia, hypokalemia, fatigue, hyponatraemia, dyspnoea and pyrexia. Thirty-day all-cause mortality, after start of treatment, was 13% vs. 25% in controls. Elacytarabine has monotherapy activity in patients with advanced AML. This study provides proof-of-concept that lipid esterification of nucleoside analogues is clinically relevant. [ABSTRACT FROM AUTHOR]

Histone H4 acetylation was examined by immunohistochemistry in patients with acute lymphocytic leukaemia (ALL) in first relapse. Univariate and multivariate models identified correlates of complete remission (CR) and overall survival (OS). No variables were associated with achievement of CR. In multivariate analysis, weak histone H4 acetylation [Hazard Ratio (HR) 2·20, 95% confidence interval (CI) 0·93-5·23, P = 0·07], shorter interval from diagnosis to relapse (<9 vs. 9-24 vs. >24 months) (HR 1·82, 95% CI 1·20-2·75, P = 0·005), and central nervous system involvement (HR 3·43, 95% CI 1·31-8·99, P = 0·01) were independent poor prognostic factors for OS. These data provide a rationale for the use of histone deacetylase inhibitors in the treatment of relapsed ALL. [ABSTRACT FROM AUTHOR]

The article presents a study that reviews survival of secondary acute myeloid leukemia (SAML) patients receiving aggressive induction chemotherapy. The study shows that the overall survival was 13.6 months and median event-free survival was eight months. It reveals that eight patients passed away shortly after receiving induction therapy due to side effects or the disease. It indicates that the median disease-free survival for patients attaining morphologic complete remission was nine months.

Thalidomide is an immunomodulatory agent with demonstrated activity in multiple myeloma, mantle cell lymphoma and lymphoplasmacytic lymphoma. Its activity is believed to be due modulation of the tumour milieu, including downregulation of angiogenesis and inflammatory cytokines. Between July 2001 and April 2004, 24 patients with relapsed/refractory indolent lymphomas received thalidomide 200 mg daily with escalation by 100 mg daily every 1–2 weeks as tolerated, up to a maximum of 800 mg daily. Patients had received a median of 2 (range, 1–4) prior regimens. Of 24 evaluable patients, two achieved a complete remission and one achieved a partial remission for an overall response rate of 12·5% (95% confidence interval: 2·6–32·4%). Eleven patients progressed during therapy. Grade 3–4 adverse effects included myelosuppression, fatigue, somnolence/depressed mood, neuropathy and dyspnea. Of concern was the occurrence of four thromboembolic events. Our results failed to demonstrate an important response rate to single agent thalidomide in indolent lymphomas and contrast with the higher activity level reported with the second generation immunomodulatory agent, lenalidomide. [ABSTRACT FROM AUTHOR]

Older AML patients have low remission rates and poor survival outcomes with standard chemotherapy. Microtransplantation (MST) refers to infusion of allogeneic hematopoietic stem cells without substantial engraftment. MST has been shown to improve clinical outcomes compared with chemotherapy alone. This is the first trial reporting on broad correlative studies to define immunologic mechanisms of action of MST in older AML patients. Older patients with newly diagnosed AML were eligible for enrollment, receiving induction chemotherapy with cytarabine (100 mg/m2) on days 1-7 and idarubicin (12 mg/m2) on days 1-3 (7 + 3). MST was administered 24 hours later. Patients with complete response (CR) were eligible for consolidation with high dose cytarabine (HiDAC) and a second cycle of MST. Responses were evaluated according to standard criteria per NCCN. Immune correlative studies were performed. Sixteen patients were enrolled and received 7 + 3 and MST (median age 73 years). Nine (56%) had high-risk and seven (44%) had standard-risk cytogenetics. Ten episodes of CRS were observed. No cases of GVHD or treatment-related mortality were reported. Event-free survival (EFS) was 50% at 6 months and 19% at 1 year. Overall survival (OS) was 63% at 6 months and 44% at 1 year. Donor microchimerism was not detected. Longitudinal changes were noted in NGS, TCR sequencing, and cytokine assays. Addition of MST to induction and consolidation chemotherapy was well tolerated in older AML patients. Inferior survival outcomes in our study may be attributed to a higher proportion of very elderly patients with high-risk features. Potential immunologic mechanisms of activity of MST include attenuation of inflammatory cytokines and emergence of tumor-specific T cell clones., (© 2020 Wiley Periodicals, Inc.)