Pharmacokinetics and immunogenicity of eftozanermin alfa in subjects with previously-treated solid tumors or hematologic malignancies: results from a phase 1 first-in-human study

PURPOSE

Eftozanermin alfa is a second-generation tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor agonist that enhances death receptor 4/5 clustering on tumor cells to induce apoptosis. We report the pharmacokinetics and immunogenicity of eftozanermin alfa administered intravenously to 153 adults with previously-treated solid tumors or hematologic malignancies from the first-in-human, open-label, dose-escalation and dose-optimization study.

METHODS

Dose escalation evaluated eftozanermin alfa monotherapy 2.5-15 mg/kg on Day 1 or Days 1/8 of a 21-day cycle. Dose optimization evaluated eftozanermin alfa monotherapy or combination therapy with either oral venetoclax 400-800 mg daily (eftozanermin alfa 1.25-7.5 mg/kg Days 1/8/15 of a 21-day cycle) or chemotherapy (eftozanermin alfa 3.75 or 7.5 mg/kg Days 1/8/15/22 of a 28-day cycle and FOLFIRI regimen [leucovorin, 5-fluorouracil, and irinotecan] with/without bevacizumab on Days 1/15 of a 28-day cycle).

RESULTS

Systemic exposures (maximum observed concentration [Cmax] and area under the concentration-time curve [AUC]) of eftozanermin alfa were approximately dose-proportional across the entire dose escalation range with minimal to no accumulation in Cycle 3 versus Cycle 1 exposures. Comparable exposures and harmonic mean half-lives (35.1 h [solid tumors], 31.3 h [hematologic malignancies]) were observed between malignancy types. Exposures (dose-normalized Cmax and AUC) in Japanese subjects were similar to non-Japanese subjects. Furthermore, eftozanermin alfa/venetoclax combination therapy did not have an impact on the exposures of either agent. Treatment-emergent anti-drug antibodies were observed in 9.4% (13/138) of subjects.

CONCLUSIONS

The study results, including a pharmacokinetic profile consistent with weekly dosing and low incidence of immunogenicity, support further investigation of eftozanermin alfa.

TRIAL REGISTRATION ID

NCT03082209.

A randomized phase III study of standard versus high-dose cytarabine with or without vorinostat for AML

Prior experience indicated that use of higher doses of cytarabine during induction for acute myeloid leukemia (AML) with a histone deacetylase inhibitor resulted in high response rates. S1203 was a randomized multicenter trial for previously untreated patients aged 18-60 with AML which compared daunorubicin and cytarabine (DA), idarubicin with higher dose cytarabine (IA) and IA with vorinostat (IA + V). The primary endpoint was event free survival (EFS). 738 patients were randomized: 261 to each DA and IA arms and 216 to the IA + V arm. 96, 456, and 150 patients had favorable-, intermediate-, and unfavorable-risk cytogenetics, respectively. 152 were NPM1 and 158 FLT3 mutated. The overall remission rate was 77.5% including 62.5% CR and 15.0% CRi. No differences in remission, EFS, or overall survival were observed among the 3 arms except for the favorable cytogenetics subset who had improved outcomes with DA and postremission high dose cytarabine. A trend towards increased toxicity was observed with the IA and IA + V arms. The use of higher dose cytarabine during induction therapy in younger patients with AML, with or without vorinostat, does not result in improved outcomes. (Funded by the US National Institutes of Health and others, ClinicalTrials.gov number, NCT01802333.).

Activity of eftozanermin alfa plus venetoclax in preclinical models and patients with acute myeloid leukemia

Activation of apoptosis in malignant cells is an established strategy for controlling cancer and is potentially curative. To assess the impact of concurrently inducing the extrinsic and intrinsic apoptosis-signaling pathways in acute myeloid leukemia (AML), we evaluated activity of the TRAIL receptor agonistic fusion protein eftozanermin alfa (eftoza; ABBV-621) in combination with the B-cell lymphoma protein-2 selective inhibitor venetoclax in preclinical models and human patients. Simultaneously stimulating intrinsic and extrinsic apoptosis-signaling pathways with venetoclax and eftoza, respectively, enhanced their activities in AML cell lines and patient-derived ex vivo/in vivo models. Eftoza activity alone or plus venetoclax required death receptor 4/5 (DR4/DR5) expression on the plasma membrane but was independent of TP53 or FLT3-ITD status. The safety/tolerability of eftoza as monotherapy and in combination with venetoclax was demonstrated in patients with relapsed/refractory AML in a phase 1 clinical trial. Treatment-related adverse events were reported in 2 of 4 (50%) patients treated with eftoza monotherapy and 18 of 23 (78%) treated with eftoza plus venetoclax. An overall response rate of 30% (7/23; 4 complete responses [CRs], 2 CRs with incomplete hematologic recovery, and 1 morphologic leukemia-free state) was reported in patients who received treatment with eftoza plus venetoclax and 67% (4/6) in patients with myoblasts positive for DR4/DR5 expression; no tumor responses were observed with eftoza monotherapy. These data indicate that combination therapy with eftoza plus venetoclax to simultaneously activate the extrinsic and intrinsic apoptosis-signaling pathways may improve clinical benefit compared with venetoclax monotherapy in relapsed/refractory AML with an acceptable toxicity profile. This trial was registered at www.clinicaltrials.gov as #NCT03082209.

CD25 targeting with the afucosylated human IgG1 antibody RG6292 eliminates regulatory T cells and CD25+ blasts in acute myeloid leukemia

Background

Acute Myeloid leukemia is a heterogeneous disease that requires novel targeted treatment options tailored to the patients' specific microenvironment and blast phenotype.

Methods

We characterized bone marrow and/or blood samples of 37 AML patients and healthy donors by high dimensional flow cytometry and RNA sequencing using computational analysis. In addition, we performed ex vivo ADCC assays using allogeneic NK cells isolated from healthy donors and AML patient material to test the cytotoxic potential of CD25 Mab (also referred to as RG6292 and RO7296682) or isotype control antibody on regulatory T cells and CD25+ AML cells.

Results

Bone marrow composition, in particular the abundance of regulatory T cells and CD25 expressing AML cells, correlated strongly with that of the blood in patients with time-matched samples. In addition, we observed a strong enrichment in the prevalence of CD25 expressing AML cells in patients bearing a FLT3-ITD mutation or treated with a hypomethylating agent in combination with venetoclax. We adopted a patient-centric approach to study AML clusters with CD25 expression and found it most highly expressed on immature phenotypes. Ex vivo treatment of primary AML patient samples with CD25 Mab, a human CD25 specific glycoengineered IgG1 antibody led to the specific killing of two different cell types, CD25+ AML cells and regulatory T cells, by allogeneic Natural Killer cells.

Conclusion

The in-depth characterization of patient samples by proteomic and genomic analyses supported the identification of a patient population that may benefit most by harnessing CD25 Mab's dual mode of action. In this pre-selected patient population, CD25 Mab could lead to the specific depletion of regulatory T cells, in addition to leukemic stem cells and progenitor-like AML cells that are responsible for disease progression or relapse.

Eftozanermin alfa (ABBV-621) monotherapy in patients with previously treated solid tumors: findings of a phase 1, first-in-human study

Eftozanermin alfa (eftoza), a second-generation tumor necrosis factor-related apoptosis-inducing ligand receptor (TRAIL-R) agonist, induces apoptosis in tumor cells by activation of death receptors 4/5. This phase 1 dose-escalation/dose-optimization study evaluated the safety, pharmacokinetics, pharmacodynamics, and preliminary activity of eftoza in patients with advanced solid tumors. Patients received eftoza 2.5-15 mg/kg intravenously on day 1 or day 1/day 8 every 21 days in the dose-escalation phase, and 1.25-7.5 mg/kg once-weekly (QW) in the dose-optimization phase. Dose-limiting toxicities (DLTs) were evaluated during the first treatment cycle to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Pharmacodynamic effects were evaluated in circulation and tumor tissue. A total of 105 patients were enrolled in the study (dose-escalation cohort, n = 57; dose-optimization cohort, n = 48 patients [n = 24, colorectal cancer (CRC); n = 24, pancreatic cancer (PaCA)]). In the dose-escalation cohort, seven patients experienced DLTs. MTD and RP2D were not determined. Most common treatment-related adverse events were increased alanine aminotransferase and aspartate aminotransferase levels, nausea, and fatigue. The one treatment-related death occurred due to respiratory failure. In the dose-optimization cohort, three patients (CRC, n = 2; PaCA, n = 1) had a partial response. Target engagement with regard to receptor saturation, and downstream apoptotic pathway activation in circulation and tumor were observed. Eftoza had acceptable safety, evidence of pharmacodynamic effects, and preliminary anticancer activity. The 7.5-mg/kg QW regimen was selected for future studies on the basis of safety findings, pharmacodynamic effects, and biomarker modulations. (Trial registration number: NCT03082209 (registered: March 17, 2017)).

Genomic landscape of patients with FLT3-mutated acute myeloid leukemia (AML) treated within the CALGB 10603/RATIFY trial

The aim of this study was to characterize the mutational landscape of patients with FLT3-mutated acute myeloid leukemia (AML) treated within the randomized CALGB 10603/RATIFY trial evaluating intensive chemotherapy plus the multi-kinase inhibitor midostaurin versus placebo. We performed sequencing of 262 genes in 475 patients: mutations occurring concurrently with the FLT3-mutation were most frequent in NPM1 (61%), DNMT3A (39%), WT1 (21%), TET2 (12%), NRAS (11%), RUNX1 (11%), PTPN11 (10%), and ASXL1 (8%) genes. To assess effects of clinical and genetic features and their possible interactions, we fitted random survival forests and interpreted the resulting variable importance. Highest prognostic impact was found for WT1 and NPM1 mutations, followed by white blood cell count, FLT3 mutation type (internal tandem duplications vs. tyrosine kinase domain mutations), treatment (midostaurin vs. placebo), ASXL1 mutation, and ECOG performance status. When evaluating two-fold variable combinations the most striking effects were found for WT1:NPM1 (with NPM1 mutation abrogating the negative effect of WT1 mutation), and for WT1:treatment (with midostaurin exerting a beneficial effect in WT1-mutated AML). This targeted gene sequencing study provides important, novel insights into the genomic background of FLT3-mutated AML including the prognostic impact of co-mutations, specific gene-gene interactions, and possible treatment effects of midostaurin.

Molecular landscape and prognostic impact of FLT3-ITD insertion site in acute myeloid leukemia: RATIFY study results

In acute myeloid leukemia (AML) internal tandem duplications of the FLT3 gene (FLT3-ITD) are associated with poor prognosis. Retrospectively, we investigated the prognostic and predictive impact of FLT3-ITD insertion site (IS) in 452 patients randomized within the RATIFY trial, which evaluated midostaurin additionally to intensive chemotherapy. Next-generation sequencing identified 908 ITDs, with 643 IS in the juxtamembrane domain (JMD) and 265 IS in the tyrosine kinase domain-1 (TKD1). According to IS, patients were categorized as JMDsole (n = 251, 55%), JMD and TKD1 (JMD/TKD1; n = 117, 26%), and TKD1sole (n = 84, 19%). While clinical variables did not differ among the 3 groups, NPM1 mutation was correlated with JMDsole (P = 0.028). Overall survival (OS) differed significantly, with estimated 4-year OS probabilities of 0.44, 0.50, and 0.30 for JMDsole, JMD/TKD1, and TKD1sole, respectively (P = 0.032). Multivariate (cause-specific) Cox models for OS and cumulative incidence of relapse using allogeneic hematopoietic cell transplantation (HCT) in first complete remission as a time-dependent variable identified TKD1sole as unfavorable and HCT as favorable factors. In addition, Midostaurin exerted a significant benefit only for JMDsole. Our results confirm the distinct molecular heterogeneity of FLT3-ITD and the negative prognostic impact of TKD1 IS in AML that was not overcome by midostaurin.

Midostaurin reduces relapse in FLT3-mutant acute myeloid leukemia: the Alliance CALGB 10603/RATIFY trial

The prospective randomized, placebo-controlled CALGB 10603/RATIFY trial (Alliance) demonstrated a statistically significant overall survival benefit from the addition of midostaurin to standard frontline chemotherapy in a genotypically-defined subgroup of 717 patients with FLT3-mutant acute myeloid leukemia (AML). The risk of death was reduced by 22% on the midostaurin-containing arm. In this post hoc analysis, we analyzed the cumulative incidence of relapse (CIR) on this study and also evaluated the impact of 12 4-week cycles of maintenance therapy. CIR analyses treated relapses and AML deaths as events, deaths from other causes as competing risks, and survivors in remission were censored. CIR was improved on the midostaurin arm (HR = 0.71 (95% CI, 0.54-0.93); p = 0.01), both overall and within European LeukemiaNet 2017 risk classification subsets when post-transplant events were considered in the analysis as events. However, when transplantation was considered as a competing risk, there was overall no significant difference between the risks of relapse on the two randomized arms. Patients still in remission after consolidation with high-dose cytarabine entered the maintenance phase, continuing with either midostaurin or placebo. Analyses were inconclusive in quantifying the impact of the maintenance phase on the overall outcome. In summary, midostaurin reduces the CIR.

Event free survival in adults with relapsed ALL who underwent front-line therapy with CALGB 10403

e19005

Background: CALGB 10403 is a pediatric-inspired ALL regimen that has recently been shown to have improved survival rates in adolescents and young adults with ALL when compared to historical outcomes with traditional adult ALL regimens (Stock et. al, 2019). Methods: This is a retrospective cohort study of ALL patients who received induction CALGB 10403 at Stanford University (both on and off trial), achieved CR1, and subsequently relapsed. Primary outcome of interest was event free survival from time of diagnosis. Events were defined as relapse or death. Secondary outcomes were overall survival and event free survival from first relapse. Patients were censored at time of last clinical follow up. Results: 25 patients met inclusion criteria and received front-line CALGB 10403 from April 2010 to September 2018. At the time of initial diagnosis median age was 30 years (range 18 – 39 years). 68% of patients were male. 48% of patients were overweight and 40% were obese. 76% of patients had precursor B cell ALL while 24% had T cell ALL. 12% had CNS disease at diagnosis. 36% of patients had WBC greater than 30k. 12% of patients had CRLF2 rearrangement. 12% of patients were MRD positive after first induction. 20% of patients received rituximab. Median event free survival time from diagnosis was 20 months (range 3 – 79 months) and median overall survival time was 53 months. Blinatumomab was the most common salvage therapy after 1st relapse, followed by inotuzumab. 15 patients (60%) achieved CR2, of which 4 (27%) were MRD positive after 2nd induction. 15 patients (60%) went to HSCT. Of the patients who achieved CR2, 8 relapsed for a second time. Median event free survival time after first relapse was 23 months. Survival 1 year after relapse was 60%. 11 of the 25 patients were alive at last follow up. Median follow up time of survivors was 6 years. Conclusions: This is a descriptive retrospective cohort study of adult patients in a real world setting who received CALGB 10403 induction and subsequently relapsed. Compared to other studies of relapsed ALL patients who were induced with traditional chemotherapy (Fielding et. al, 2007), survival 1 year after relapse was much higher (60% vs. 22%). As CALGB 10403 becomes an increasingly common induction regimen for AYA and adults with ALL, further outcomes study is required.[Table: see text]

Plasma Microbial Cell-free DNA Next Generation Sequencing in the Diagnosis and Management of Febrile Neutropenia

Background

Standard testing fails to identify a pathogen in most patients with febrile neutropenia (FN). We evaluated the ability of the Karius microbial cell-free DNA sequencing test (KT) to identify infectious etiologies of FN and its impact on antimicrobial management.

Methods

This prospective study (ClinicalTrials.gov; NCT02912117) enrolled and analyzed 55 patients with FN. Up to 5 blood samples were collected per subject within 24 hours of fever onset (T1) and every 2 to 3 days. KT results were compared with blood culture (BC) and standard microbiological testing (SMT) results.

Results

Positive agreement was defined as KT identification of ≥1 isolate also detected by BC. At T1, positive and negative agreement were 90% (9/10) and 31% (14/45), respectively; 61% of KT detections were polymicrobial. Clinical adjudication by 3 independent infectious diseases specialists categorized Karius results as: unlikely to cause FN (N = 0); definite (N = 12): KT identified ≥1 organism also found by SMT within 7 days; probable (N = 19): KT result was compatible with a clinical diagnosis; possible (N = 10): KT result was consistent with infection but not considered a common cause of FN. Definite, probable, and possible cases were deemed true positives. Following adjudication, KT sensitivity and specificity were 85% (41/48) and 100% (14/14), respectively. Calculated time to diagnosis was generally shorter with KT (87%). Adjudicators determined real-time KT results could have allowed early optimization of antimicrobials in 47% of patients, by addition of antibacterials (20%) (mostly against anaerobes [12.7%]), antivirals (14.5%), and/or antifungals (3.6%); and antimicrobial narrowing in 27.3% of cases.

Clinical Trials Registration

NCT02912117

Conclusion

KT shows promise in the diagnosis and treatment optimization of FN.

Economic and Clinical Burden of Acute Myeloid Leukemia Episodes of Care in the United States: A Retrospective Analysis of a Commercial Payer Database

BACKGROUND

In the United States, the incidence of acute myeloid leukemia (AML) has steadily increased over the last decade; in 2019, it was estimated that AML would affect 21,450 new patients and lead to 10,920 deaths. Detailed real-world cost estimates and comparisons of key AML treatment episodes, such as in high-intensity chemotherapy (HIC), low-intensity chemotherapy (LIC), hematopoietic stem cell transplantation (HSCT), and relapsed/refractory (R/R), are scarce in the commercially insured U.S.

POPULATION

OBJECTIVE

To examine health resource utilization (HRU), clinical burden, and direct health care costs across various AML treatment episodes in a large sample of commercially insured U.S.

PATIENTS

METHODS

A retrospective cohort analysis was conducted. Patients with newly diagnosed AML were followed to identify the key active treatment episodes across the course of their disease. Data were obtained from 2 sources: IQVIA's Real-World Data (RWD) Adjudicated Claims Database - U.S. (formerly known as PharMetrics Plus), which comprises adjudicated claims for more than 150 million unique enrollees across the United States, and IQVIA Charge Detail Master Hospital Database, which has detailed data regarding services received in an inpatient setting. Calculation of all-cause HRU was based on physician office visits, nonphysician office visits, emergency department visits, inpatient visits, and outpatient pharmacy utilization. Calculation of all-cause health care costs was based on total allowed costs and reported by the following cost components: physician office visits, nonphysician office visits, emergency department visits, inpatient visits, and outpatient pharmacy utilization. Symptom and toxicity events were estimated via proxies such as diagnosis codes, procedures, and treatments administered.

RESULTS

The final study sample consisted of 1,542 HIC-induction (HIC-I), 591 HIC-consolidation (HIC-C), 628 LIC, 1,000 patients with HSCT, and 707 patients with R/R AML. Total mean episode costs were highest in R/R episodes ($439,104), followed by HSCT ($329,621), HIC-I ($198,657), HIC-C ($73,428), and LIC ($53,081) episodes. Across all treatment episodes, hospitalization was the largest contributor to cost with mean hospitalization costs ranging from $308,978 in the R/R setting to $49,580 for patients receiving LIC; of these, costs related to intensive care unit admission were a noteworthy contributor. In patients with R/R AML and HSCT, expenditures related to pharmacy utilization averaged $24,640 and $12,203, respectively, and expenditures related to physician office visits averaged $10,926 and $6,090, respectively; these expenditures were much lower across other episodes. Across all categories of symptom and toxicity events, cardiovascular events was the only category of event that was a significant predictor of higher cost across all episodes. Symptom and toxicity events commonly associated with AML were associated with significantly increased costs, especially in R/R episodes.

CONCLUSIONS

This resource utilization and direct health care cost analysis highlights the substantial economic burden associated with key AML treatment episodes in the United States, specifically during HIC-I, HSCT, and R/R episodes.

DISCLOSURES

This study was funded by Astellas Pharma. Astellas employees were involved in the study design, interpretation of data, writing of the manuscript, and the decision to submit the manuscript for publication. Pandya and Wilson are employees of Astellas Pharma U.S. Walsh was an employee of Astellas Pharma U.S. while the study was conducted. Chen, McGuiness, and Wade are employees of IQVIA, which received funding from Astellas Pharma U.S. Madeiros was employed at Stanford University while this study was conducted and received a consulting fee from Astellas for work on this study. Data discussed in this study were previously presented at the 59th Annual American Society for Hematology Meeting & Exposition, 2017; December 9-12, 2017; Atlanta, GA.

Increased mitochondrial apoptotic priming with targeted therapy predicts clinical response to re-induction chemotherapy

Most patients with relapsed or refractory (R/R) acute myeloid leukemia (AML) do not benefit from current re-induction or approved targeted therapies. In the absence of targetable genetic mutations, there is minimal guidance on optimal treatment selection particularly in the R/R setting highlighting an unmet need for clinically useful functional biomarkers. Blood and bone marrow samples from patients treated on two clinical trials were used to test the combination of lenalidomide (LEN) and MEC (mitoxantrone, etoposide, and cytarabine) chemotherapy in R/R AML patients. The bone marrow samples were available to test the clinical utility of the mitochondrial apoptotic BH3 and dynamic BH3 profiling (DBP) assays in predicting response, as there was no clear genetic biomarker identifying responders. To test whether LEN-induced mitochondrial priming predicted clinical response to LEN-MEC therapy, we performed DBP on patient myeloblasts. We found that short-term ex vivo treatment with lenalidomide discriminated clinical responders from non-responders based on drug-induced change in priming (delta priming). Using paired patient samples collected before and after clinical LEN treatment (prior to MEC dosing), we confirmed LEN-induced increased apoptotic priming in vivo, suggesting LEN enhanced vulnerability of myeloblasts to cytotoxic MEC chemotherapy. This is the first study demonstrating the potential role of DBP in predicting clinical response to a combination regimen. Our findings demonstrate that functional properties of relapsed AML can identify active therapies.

Rapid Donor Identification Improves Survival in High-Risk First-Remission Patients With Acute Myeloid Leukemia

PURPOSE

Patients with acute myeloid leukemia with high-risk cytogenetics in first complete remission (CR1) achieve better outcomes if they undergo allogeneic hematopoietic cell transplantation (HCT) compared with consolidation chemotherapy alone. However, only approximately 40% of such patients typically proceed to HCT.

METHODS

We used a prospective organized approach to rapidly identify donors to improve the allogeneic HCT rate in adults with high-risk acute myeloid leukemia in CR1. Newly diagnosed patients had cytogenetics obtained at enrollment, and those with high-risk cytogenetics underwent expedited HLA typing and were encouraged to be referred for consultation with a transplantation team with the goal of conducting an allogeneic HCT in CR1.

RESULTS

Of 738 eligible patients (median age, 49 years; range, 18-60 years of age), 159 (22%) had high-risk cytogenetics and 107 of these patients (67%) achieved CR1. Seventy (65%) of the high-risk patients underwent transplantation in CR1 (P < .001 compared with the historical rate of 40%). Median time to HCT from CR1 was 77 days (range, 20-356 days). In landmark analysis, overall survival (OS) among patients who underwent transplantation was significantly better compared with that of patients who did not undergo transplantation (2-year OS, 48% v 35%, respectively [P = .031]). Median relapse-free survival after transplantation in the high-risk cohort who underwent transplantation in CR1 (n = 70) was 11.5 months (range, 4-47 months), and median OS after transplantation was 14 months (range, 4-44 months).

CONCLUSION

Early cytogenetic testing with an organized effort to identify a suitable allogeneic HCT donor led to a CR1 transplantation rate of 65% in the high-risk group, which, in turn, led to an improvement in OS when compared with the OS of patients who did not undergo transplantation.

Functional characterization of two rare BCR-FGFR1+ leukemias

8p11 myeloproliferative syndrome (EMS) represents a unique World Health Organization (WHO)-classified hematologic malignancy defined by translocations of the FGFR1 receptor. The syndrome is a myeloproliferative neoplasm characterized by eosinophilia and lymphadenopathy, with risk of progression to either acute myeloid leukemia (AML) or T- or B-lymphoblastic lymphoma/leukemia. Within the EMS subtype, translocations between breakpoint cluster region (BCR) and fibroblast growth factor receptor 1 (FGFR1) have been shown to produce a dominant fusion protein that is notoriously resistant to tyrosine kinase inhibitors (TKIs). Here, we report two cases of BCR–FGFR1⁺ EMS identified via RNA sequencing (RNA-seq) and confirmed by fluorescence in situ hybridization (FISH). Sanger sequencing revealed that both cases harbored the exact same breakpoint. In the first case, the patient presented with AML-like disease, and in the second, the patient progressed to B-cell acute lymphoblastic leukemia (B-ALL). Additionally, we observed that that primary leukemia cells from Case 1 demonstrated sensitivity to the tyrosine kinase inhibitors ponatinib and dovitinib that can target FGFR1 kinase activity, whereas primary cells from Case 2 were resistant to both drugs. Taken together, these results suggest that some but not all BCR–FGFR1 fusion positive leukemias may respond to TKIs that target FGFR1 kinase activity.

Genomic landscape of neutrophilic leukemias of ambiguous diagnosis

Chronic neutrophilic leukemia (CNL), atypical chronic myeloid leukemia (aCML), and myelodysplastic/myeloproliferative neoplasms, unclassifiable (MDS/MPN-U) are a group of rare and heterogeneous myeloid disorders. There is strong morphologic resemblance among these distinct diagnostic entities as well as a lack of specific molecular markers and limited understanding of disease pathogenesis, which has made diagnosis challenging in certain cases. The treatment has remained empirical, resulting in dismal outcomes. We, therefore, performed whole-exome and RNA sequencing of these rare hematologic malignancies and present the most complete survey of the genomic landscape of these diseases to date. We observed a diversity of combinatorial mutational patterns that generally do not cluster within any one diagnosis. Gene expression analysis reveals enrichment, but not cosegregation, of clinical and genetic disease features with transcriptional clusters. In conclusion, these groups of diseases represent a continuum of related diseases rather than discrete diagnostic entities.

Longer distance to specialized treatment centers does not adversely affect treatment intensity or outcomes in adult acute myeloid leukemia patients. A Danish national population-based cohort study

Background

Treatment of acute myeloid leukemia (AML) is widely centralized. Longer distances to a specialized treatment center may affect patients’ access to curative-intended treatment. Especially during outpatient treatment, distance may also affect survival.

Methods and patients

The authors conducted a national population-based cohort study including all AML patients diagnosed in Denmark between 2000 and 2014. We investigated effects of distance (<10 kilometers [km; reference], 10–25, 25–50, 50–100, >100) to the nearest specialized treatment facility on the probability of receiving intensive chemotherapy, HSCT, and achieving a complete remission (CR) using logistic regression analysis (odds ratios; ORs). For overall survival, we used Cox proportional hazards regression (hazard ratios [HRs]) and adjusted (a) for relevant baseline characteristics.

Results

Of 2,992 patients (median age=68.5 years), 53% received intensive chemotherapy and 12% received low-dose chemotherapy outpatient regimens. The median distance to a specialized treatment center was 40 km (interquartile range=10–77 km). No impact of distance to specialized treatment centers was seen on the probability of receiving intensive chemotherapy (10–25 km, aOR=1.1 (CI=0.7–1.7), 25–50 km, aOR=1.1 (CI=0.7–1.7), 50–100 km, aOR=1.3 (CI=0.9–1.9), and >100 km, aOR=1.4 [CI=0.9–2.2]). Overall survival in patients regardless of therapy (<10 km, aOR=1.0 vs >100 km, aOR=1.0 [CI=0.9–1.2]), in intensive therapy patients, or in patients’ choice of post-remission was not affected by distance to specialized treatment center. Distance to a transplant center also did not affect the probability of HSCT or survival post-HSCT.

Conclusion

In Denmark, distance to a specialized treatment facility offering remission-induction chemotherapy and HSCT does not negatively affect access to curative-indented therapy, treatment-response, or survival in AML patients.

Economic and Clinical Burden of Relapsed and/or Refractory Active Treatment Episodes in Patients with Acute Myeloid Leukemia (AML) in the USA: A Retrospective Analysis of a Commercial Payer Database

This retrospective study estimated healthcare resource use (HRU), symptoms and toxicities (SxTox), and costs in relapsed/refractory (R/R) patients with acute myeloid leukemia (AML), stratified by hematopoietic stem cell transplantation (HSCT) status. Claims data were used to identify adult patients with AML diagnoses from 1 January 2008 to 31 March 2016 in the USA. Patients were considered R/R if they had an AML relapse ICD-9 code (205.02) or a line of therapy consistent with R/R disease. The final R/R sample (N = 707) included 476 patients with and 231 patients without HSCT. The mean total episode cost (from relapse date to death or end of study period) for all patients was $439,104 (with HSCT $524,595 and without HSCT $263,310). Inpatient visits accounted for the greatest cost component (mean $308,978) followed by intensive care unit stays (mean $221,537), non-clinician (e.g., lab tests) visits (mean $30,909), and outpatient pharmacy utilization (mean $24,640). Patients with HSCT appeared to have longer episodes of care compared with patients without HSCT (16.8 vs 11.1 months), perhaps reflecting longer survival for HSCT patients. Mean number of visits within each category and their associated costs appeared to be higher in patients with HSCT compared with patients without HSCT. Patients with HSCT appeared to experience more SxTox compared with patients without HSCT across all categories. Results of the current study suggest that there is a substantial HRU and cost burden on R/R AML patients in the USA receiving active treatments. More effective therapies with improved tolerability would meet this tremendous unmet need in the R/R AML population.

Funding: Astellas Pharma, Inc.

Safety and efficacy of oral panobinostat plus chemotherapy in patients aged 65 years or younger with high-risk acute myeloid leukemia

The role of histone deacetylase inhibitors in the treatment of acute myeloid leukemia (AML) is not well characterized. The current study evaluated the safety and efficacy of panobinostat in combination with idarubicin and cytarabine in newly diagnosed patients aged ≤65 years with primary or secondary high-risk AML based on cytogenetic classification. Treatment included fixed dose idarubicin (12 mg/m²/d, IV; day 1-3) and cytarabine (100 mg/m²/d, continuous IV infusion; day 1-7) and escalating oral doses of panobinostat at 15 mg, 20 mg, and 25 mg, thrice weekly starting at week 2 of a 28-day cycle. Forty-six patients were enrolled (primary AML [n = 36], secondary AML [n = 10]). The median age was 55 years. The most common all-grade AEs were diarrhea (54.3%), nausea (39.1%), vomiting, and decreased appetite (each, 21.7%), stomatitis (19.6%), and fatigue (17.4%). The overall response rate was 60.9%, 43.5% achieved a complete remission (CR), and 17.4% achieved CR with incomplete count recovery. The event-free survival at 1-year was 78.3%. Panobinostat in combination with idarubicin and cytarabine demonstrated tolerable safety and efficacy in younger patients with high-risk AML. The recommended phase 2 dose of panobinostat in this combination was 20 mg. ClinicalTrials.gov registry no: NCT01242774, and European Trial Registry EudraCT no: 2009-016809-42.

Acute myeloid leukemia immunopeptidome reveals HLA presentation of mutated nucleophosmin

Somatic mutations in cancer are a potential source of cancer specific neoantigens. Acute myeloid leukemia (AML) has common recurrent mutations shared between patients in addition to private mutations specific to individuals. We hypothesized that neoantigens derived from recurrent shared mutations would be attractive targets for future immunotherapeutic approaches. Here we sought to study the HLA Class I and II immunopeptidome of thirteen primary AML tumor samples and two AML cell lines (OCI-AML3 and MV4-11) using mass spectrometry to evaluate for endogenous mutation-bearing HLA ligands from common shared AML mutations. We identified two endogenous, mutation-bearing HLA Class I ligands from nucleophosmin (NPM1). The ligands, AVEEVSLRK from two patient samples and C(cys)LAVEEVSL from OCI-AML3, are predicted to bind the common HLA haplotypes, HLA-A*03:01 and HLA-A*02:01 respectively. Since NPM1 is mutated in approximately one-third of patients with AML, the finding of endogenous HLA ligands from mutated NPM1 supports future studies evaluating immunotherapeutic approaches against this shared target, for this subset of patients with AML.

Optimizing survival outcomes with post-remission therapy in acute myeloid leukemia

Optimization of post‐remission therapies to maintain complete remission and prevent relapse is a major challenge in treating patients with acute myeloid leukemia (AML). Monitoring patients for measurable residual disease (MRD) is helpful to identify those at risk for relapse. Hypomethylating agents are being investigated as post‐remission therapy. Identification of recurrent genetic alterations that drive disease progression has enabled the design of new, personalized approaches to therapy for patients with AML. Emerging data suggest that targeted post‐remission therapy, alone or in combination with chemotherapy, may improve outcomes. Results of ongoing clinical trials will further define potential clinical benefits.

Development and Validation of a Novel Acute Myeloid Leukemia-Composite Model to Estimate Risks of Mortality

Question

Can a model incorporating patient-specific (comorbidities and age) and acute myeloid leukemia (AML)-specific features (cytogenetic and molecular alterations) predict mortality after AML treatment?

Findings

In a multicenter cohort study of 1100 patients, we demonstrated that (1) comorbidities had a significant impact on 1-year mortality after initial therapy for AML, (2) an augmented hematopoietic cell transplant–comorbidity index (HCT-CI) was the best suited index for comorbidity evaluation in AML, and (3) an AML composite model of augmented HCT-CI, age, and cytogenetic/molecular risks has a strong AUC of 0.76 for 1-year mortality.

Meaning

An AML composite model can guide decision-making about treatment of AML.

Importance

To our knowledge, this multicenter analysis is the first to test and validate (1) the prognostic impact of comorbidities on 1-year mortality after initial therapy of acute myeloid leukemia (AML) and (2) a novel, risk-stratifying composite model incorporating comorbidities, age, and cytogenetic and molecular risks.

Objective

To accurately estimate risks of mortality by developing and validating a composite model that combines the most significant patient-specific and AML-specific features.

Design, Setting, and Participants

This is a retrospective cohort study. A series of comorbidities, including those already incorporated into the hematopoietic cell transplantation–comorbidity index (HCT-CI), were evaluated. Patients were randomly divided into a training set (n = 733) and a validation set (n = 367). In the training set, covariates associated with 1-year overall mortality at a significance level of P < .10 constructed a multivariate Cox proportional hazards model in which the impact of each covariate was adjusted for that of all others. Then, the adjusted hazard ratios were used as weights. Performances of models were compared using C statistics for continuous outcomes and area under the curve (AUC) for binary outcomes.

Exposures

Initial therapy for AML.

Main Outcomes and Measures

Death within 1 year after initial therapy for AML.

Results

A total of 1100 patients, ages 20 to 89 years, were treated for AML between January 1, 2008, and December 31, 2012, at 5 academic institutions specialized in treating AML; 605 (55%) were male, and 495 (45%) were female. In the validation set, the original HCT-CI had better C statistic and AUC estimates compared with the AML comorbidity index for prediction of 1-year mortality. Augmenting the original HCT-CI with 3 independently significant comorbidities, hypoalbuminemia, thrombocytopenia, and high lactate dehydrogenase level, yielded a better C statistic of 0.66 and AUC of 0.69 for 1-year mortality. A composite model comprising augmented HCT-CI, age, and cytogenetic/molecular risks had even better predictive estimates of 0.72 and 0.76, respectively.

Conclusions and Relevance

In this cohort study, comorbidities influenced 1-year survival of patients with AML, and comorbidities are best captured by an augmented HCT-CI. The augmented HCT-CI, age, and cytogenetic/molecular risks could be combined into an AML composite model that could guide treatment decision-making and trial design in AML. Studying physical, cognitive, and social health might further clarify the prognostic role of aging. Targeting comorbidities with interventions alongside specific AML therapy might improve survival.

Treatment patterns in patients with acute myeloid leukemia in the United States: a cross-sectional, real-world survey

OBJECTIVE

The aim of this analysis was to examine treatment patterns in patients with acute myeloid leukemia (AML) in routine clinical practice in the United States, including factors influencing the choice of front-line treatment intensity and the effect of age and treatment line.

METHODS

We used data from the Adelphi AML Disease Specific Programme, a real-world, cross-sectional survey conducted in 2015. Physicians completed patient record forms providing patients' demographic and clinical characteristics.

RESULTS

In total, 61 academic, non-academic, and office-based hematologists and hematology/oncology specialists provided data on 457 patients with AML; 284 had ≥20% blasts (World Health Organization defined AML) and were included in the analysis. In the front-line setting, 60% of patients received high-intensity therapy, most commonly cytarabine plus anthracycline; the most common low-intensity treatments were hypomethylating agents. Primary drivers for selecting high-intensity versus low-intensity treatment were age, performance status and comorbidities; 67%, 64% and 61% of physicians stated they would prescribe high-intensity treatment to patients aged <65 years, with good performance status or no comorbidities, respectively. In practice, patients aged <60 years were more likely to receive high-intensity induction treatment (high vs. low intensity by age p < .0001). In a selected cohort of relapsed/refractory patients, 69% of patients received high-intensity therapy (78% of patients aged <60 years and 57% of patients aged ≥60 years).

CONCLUSIONS

Most patients in this analysis of real-world survey data received well established, front-line induction therapies. Treatment intensity was determined by age, comorbidities and performance status, as recommended by guidelines.

Real-World Impact of Physician and Patient Discordance on Health-Related Quality of Life in US Patients with Acute Myeloid Leukemia

Introduction

There is limited understanding concerning the health-related quality of life (HRQoL) in acute myeloid leukemia (AML) patients. Due to an overlap of symptoms, it can be difficult to separate disease versus treatment-related effects. Study objectives were to understand the impact of factors that might influence patients’ HRQoL, assess the degree of concordance in symptom reporting by patients and physicians, and assess the impact of any discordance on HRQoL in AML patients.

Methods

Physicians in the USA captured demographics, current AML treatment and symptoms for 82 AML patients who completed the Functional Assessment of Cancer Therapy-Leukemia (FACT-Leu), 5-Dimension EuroQol Questionnaire (EQ-5D-3L) and Cancer Treatment Satisfaction Questionnaire (CTSQ). Effect size (ES) and clinically meaningful differences between AML subgroups were assessed, as was the impact of disagreement between patients and physicians regarding symptom recognition.

Results

Clinically meaningful lower overall FACT-Leu scores were observed for: relapsed/refractory versus non-relapsed/refractory AML patients (92.5 vs. 103.7; P = 0.09; ES = 0.439), hypomethylating agent (HMA) monotherapy versus other therapies in patients with low treatment intensity (89.9 vs. 112.9; P = 0.0021; ES = 0.971) and presence/absence of FLT3-ITD mutation (85.5 vs. 100; P = 0.148; ES = 0.816). Differences in health state were also clinically meaningful between patients with/without FLT3-ITD; EQ-5D-Visual Analog Scale (VAS) (47.6 vs. 63.7; P = 0.0428; ES = 0.816). Patients were more likely than physicians to report bruising (κ = 0.1292), fatigue (κ = 0.0836), bleeding (κ = 0.0177), weight loss (κ = 0.0821) and appetite loss (κ = − 0.0246). FACT-Leu was associated with patient-physician discordance on bleeding (difference − 14.12; P = 0.046), weight loss (− 21.22; P = 0.001) and appetite loss (− 12.58; P = 0.027).

Conclusions

HRQoL is generally low for AML patients, especially for particular subgroups. Discordance in symptom reporting between patients and physicians was common and associated with further negative impacts on HRQoL. There may be many reasons for this but better communication between physicians and patients may lead to shared objectives and improvement in patients’ HRQoL.

Funding

Astellas Pharma, Inc.

Electronic supplementary material

The online version of this article (10.1007/s40487-019-0094-x) contains supplementary material, which is available to authorized users.

Addressing the room for improvement in management of acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is highly curable. To achieve high cure rates, targeted therapy with retinoic acid (ATRA) must be started promptly at time of suspected diagnosis. Early death rates (EDRs, ≤30 days from diagnosis) differ markedly in patients treated on clinical trials compared to the general population.

OBJECTIVES AND METHODS

We used the comprehensive Danish National Acute Leukemia Registry (DNLR) to investigate the incidence, treatment, EDR, and long-term clinical outcome in APL between 2000 and 2014.

RESULTS

Twenty-two of 41 deaths occurring in 122 APL patients were EDs which were primarily caused by intracranial hemorrhage, disseminated intravascular coagulation (DIC), sepsis, and multiorgan failure. The overall EDR was 18.0%, whereas clinical trial participants had an EDR of 6.7%. Fifteen patients recruited to the NCRI AML17 APL trial from 2010 to 2013 were younger and had decreased mortality (HR 0.18, CI 0.04-0.86, P = 0.02) compared to contemporarily treated patients (n = 15) not recruited to a clinical trial. Performance status, leukemia origin, and Sanz-score were independent prognostic variables.

CONCLUSIONS

The very low EDR for on-trial patients is not observed in the general cohort of APL patients. Diagnostic awareness emerges as the greatest clinical challenge in management of APL.

The relationship between clinical trial accrual volume and outcomes in acute myeloid leukemia: A SWOG/ECOG-ACRIN study (S0106 and E1900)

PURPOSE

To study whether institutional clinical trial accrual volume affects clinical outcomes of younger (age less than 61 years) patients with acute myeloid leukemia.

PATIENTS AND METHODS

We investigated the impact of clinical trial accrual on response rates, early mortality and survival in patients with AML enrolled between 2002 and 2009 into two parallel cooperative group clinical trials SWOG S0106/ECOG-ACRIN E1900. Institutions were classified as low- (LAIs) (≤ 9 enrolled patients) or high-accruing institutions (HAIs) (≥10 enrolled patients). Fisher's exact text and logistic regression analysis were used to analyze the response and early mortality rates. The effect of accrual volume on survival was analyzed by log-rank tests and Cox regression models.

RESULTS

A total of 1252 patients from 152 institutions were included in the final analyses. The median clinical trial registrations in HAIs was 19 patients (range, 10 to 92) versus 3 (range, 1 to 9) patients in LAIs. In multivariate analyses, HAIs, as a quantitative covariate, was associated with improved complete remission rates (odds ratio (OR) 1.08, p = 0.0051), but no improvement median overall survival (HR 0.97, p = 0.065) or median event-free (hazard ratio (HR) 0.97, p = 0.05). Early mortality rates were similar between cohorts and academic affiliation had no impact on response rates or survival.

CONCLUSION

Clinical trial accrual volume, had an independent, albeit modest, impact on complete remission rates, but not on overall survival and event-free in younger patients with AML.

NSAID consumption and risk of acute myeloid leukemia: a national population-based case-control study

Background

Most cases of acute leukemia arise without identifiable risk factors. Studies investigating the impact of autoimmune diseases and infections on leukemogenesis have revealed conflicting results. If inflammation increases the risk of acute myeloid leukemia (AML), nonsteroidal anti-inflammatory drug (NSAID) use may decrease the risk of leukemia.

Methods

We conducted a case-control study of 3,053 patients with AML diagnosed between 2000 and 2013, who were registered in the Danish National Acute Leukemia Registry, and 30,530 population controls matched on sex and age. We identified prescriptions through the Danish National Health Service Prescription Database. We used conditional logistic regression analysis to compute ORs associating AML with NSAID use overall, in patients with inflammatory diseases, and for specific AML subtypes (de novo AML, AML related to previous hematological disease, ie, secondary AML [sAML], or therapy-related AML [tAML; exposed to previous cytotoxic therapy]).

Results

Overall, NSAID use was not associated with a lower risk of AML (OR 1.1, 95% CI=1.0-1.2), de novo AML (OR 1.0, 95% CI=0.9-1.1), and sAML/tAML (OR 1.3, 95% CI=1.1-1.5). In addition, in patients with known inflammatory diseases, NSAIDs did not affect AML risk (OR 0.9, 95% CI=0.5-1.6). Number of prescriptions, type of NSAID, age, or sex did not influence the results.

Conclusion

In line with our recent findings that showed no association between autoimmune diseases and infections and de novo AML, NSAID use was not found to reduce the risk of AML.

Functional genomic landscape of acute myeloid leukaemia

The implementation of targeted therapies for acute myeloid leukaemia (AML) has been challenging because of the complex mutational patterns within and across patients as well as a dearth of pharmacologic agents for most mutational events. Here we report initial findings from the Beat AML programme on a cohort of 672 tumour specimens collected from 562 patients. We assessed these specimens using whole-exome sequencing, RNA sequencing and analyses of ex vivo drug sensitivity. Our data reveal mutational events that have not previously been detected in AML. We show that the response to drugs is associated with mutational status, including instances of drug sensitivity that are specific to combinatorial mutational events. Integration with RNA sequencing also revealed gene expression signatures, which predict a role for specific gene networks in the drug response. Collectively, we have generated a dataset-accessible through the Beat AML data viewer (Vizome)-that can be leveraged to address clinical, genomic, transcriptomic and functional analyses of the biology of AML.

CPX-351 (cytarabine and daunorubicin) Liposome for Injection Versus Conventional Cytarabine Plus Daunorubicin in Older Patients With Newly Diagnosed Secondary Acute Myeloid Leukemia

Purpose

CPX-351 is a dual-drug liposomal encapsulation of cytarabine and daunorubicin that delivers a synergistic 5:1 drug ratio into leukemia cells to a greater extent than normal bone marrow cells. Prior clinical studies demonstrated a sustained drug ratio and exposure in vivo and prolonged survival versus standard-of-care cytarabine plus daunorubicin chemotherapy (7+3 regimen) in older patients with newly diagnosed secondary acute myeloid leukemia (sAML).

Patients and Methods

In this open-label, randomized, phase III trial, 309 patients age 60 to 75 years with newly diagnosed high-risk/sAML received one to two induction cycles of CPX-351 or 7+3 followed by consolidation therapy with a similar regimen. The primary end point was overall survival.

Results

CPX-351 significantly improved median overall survival versus 7+3 (9.56 v 5.95 months; hazard ratio, 0.69; 95% CI, 0.52 to 0.90; one-sided P = .003). Overall remission rate was also significantly higher with CPX-351 versus 7+3 (47.7% v 33.3%; two-sided P = .016). Improved outcomes were observed across age-groups and AML subtypes. The incidences of nonhematologic adverse events were comparable between arms, despite a longer treatment phase and prolonged time to neutrophil and platelet count recovery with CPX-351. Early mortality rates with CPX-351 and 7+3 were 5.9% and 10.6% (two-sided P = .149) through day 30 and 13.7% and 21.2% (two-sided P = .097) through day 60.

Conclusion

CPX-351 treatment is associated with significantly longer survival compared with conventional 7+3 in older adults with newly diagnosed sAML. The safety profile of CPX-351 was similar to that of conventional 7+3 therapy.

Abstract 568: Recurrent drug sensitivity patterns in myelodysplastic syndrome patients are recapitulated by ex vivo drug response profiling

Myelodysplastic syndromes (MDS) are a collection of clonal diseases of dysfunctional hematopoietic stem cells, characterized by ineffective hematopoiesis, cytopenias, and dysplasia. Limited conventional treatment options exist for these patients, with hypomethylating agents remaining the standard of care for higher-risk MDS patients. Drug sensitivity and resistance testing on myelodysplastic syndromes (MDS) samples should provide important functional information to guide actionable target and biomarker discovery. We provide proof-of-concept data by profiling the effects of 50 common oncology drugs on 14 myelodysplastic (MDS) samples from both treatment-naïve and refractory cases. Ex vivo high-throughput functional screening was performed on lysed peripheral blood and/or bone marrow aspirate patient samples. This set of samples was analyzed 72 hours post incubation and blasts were quantified by flow cytometry. Unsupervised hierarchical clustering was performed to determine similar responses between patient samples, and produced two distinct groups with differing sensitivity to tested drugs. We defined these groups as “sensitive” and “resistant” clusters based on the prevailing drug sensitivity patterns these groups displayed, the latter being strongly enriched for HMA refractory samples. Ex vivo testing recapitulated known patient drug sensitivity patterns, with 12/14 samples from known HMA refractory vs. sensitive patients showing similar ex vivo phenotypes. Interestingly, sensitive and resistant clusters strongly correlated with known features associated with therapy resistance and poor prognosis in MDS patients, including number of somatic driver mutations (average 2.38 vs. 4.5, P &lt;0.05), absence vs. presence of RUNX1 or ASXL1 mutations (P 0.015 and 0.0256, respectively), and HMA sensitive vs. refractory status (P &lt;0.05). Interestingly, percent bone marrow blasts, cytogenetic risk groups and other somatic mutations had no effect on sensitivity patterns. Furthermore, while the resistant cluster showed increased resistance to most drugs, some drugs seemed to have increased activity in this cluster, including calcitriol and poly ADP ribose polymerase (PARP) inhibitor rucaparib. This unique platform, applied to predict ex vivo therapeutic response of MDS patient samples to various classes of drugs, recapitulates known clinical and molecular predictors of therapeutic response, and possible new therapeutic targets. These data suggest the possible utility of using this methodology to aid decision making for therapeutic selection in the management of MDS patients.

Citation Format: Alexey Aleshin, Bruno C. Medeiros, Savita Kamble, Diane Heiser, Marianne Santaguida, Sacha Prashad, Peter L. Greenberg. Recurrent drug sensitivity patterns in myelodysplastic syndrome patients are recapitulated by ex vivo drug response profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 568.

Abstract 3004: Single-cell mutational profiling of clonal evolution in myelodysplastic syndromes (MDS) during therapy and disease progression

Myelodysplastic syndromes (MDS) are a collection of clonal diseases with dysfunctional hematopoietic stem cells, characterized by ineffective hematopoiesis, cytopenias, and dysplasia. MDS is increasingly being recognized as a molecularly heterogeneous disease with variability in clinical phenotype, prognosis, and response to treatment. The clonal evolution in response to therapy remains a challenge in the management of MDS. However, resolution of complex clonal architectures is difficult with current bulk sequencing approaches. High-throughput single-cell genomic profiling enables the resolution of tumor heterogeneity, and may improve clinical diagnosis and treatment monitoring by allowing for characterization and early identification of resistant subclonal populations. To enable the characterization of genetic heterogeneity in tumor cell populations, we developed a novel microfluidic approach that barcodes amplified genomic DNA from thousands of individual cells confined to droplets. The barcodes were then used to reassemble the genetic profiles of cells from next-generation sequencing data. We applied this approach to sequential clinical MDS samples, genotyping the most clinically relevant loci across more than 15,000 individual cells. Additionally, to study effects of subclonal mutations on drug sensitivity, ex vivo functional testing was performed on red blood cell-lysed peripheral blood and/or bone marrow aspirate patient samples. Targeted single-cell sequencing was able to recapitulate bulk sequencing data from both peripheral blood and bone marrow aspirate samples. Furthermore, the single-cell nature of our approach enabled definitive determination of mutational co-occurrence within the same cell. For examples in one sample, bulk sequencing identified mutations in JAK2 and NRAS both at 3% variant allele frequency (VAF), where single-cell analysis suggested that these mutations were mutually exclusive, each defining a distinct subclone. Single-cell sequencing allowed for serial monitoring of clonal evolution, with analysis of sequential samples from this same patient showing increase of NRAS clone from 2.5% to 24.7% at time of disease progression after hypomethylating agent therapy. Furthermore, single-cell analysis was able to identify a distinct subclone characterized by a KRAS mutation (0.4% at initiation of therapy and 6.7% at relapse), missed by serial bulk sequencing. Taken together, our results suggest a greater degree of heterogeneity in MDS samples than suggested with bulk sequencing methods alone, and demonstrate utility of single-cell sequencing for sequential monitoring and identification of resistant clones prior to therapy initiation. We show here that this approach is a feasible, scalable, and effective way to identify and track heterogeneous populations of cells in MDS.

Citation Format: Alexey Aleshin, Peter L. Greenberg, Bruno C. Medeiros, Diane Heiser, Marianne Santaguida, Sacha Prashad, Robert Durruthy- Durruthy, Dennis J. Eastburn. Single-cell mutational profiling of clonal evolution in myelodysplastic syndromes (MDS) during therapy and disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3004.

A phase I, open-label, dose-escalation study of amrubicin in combination with lenalidomide and weekly dexamethasone in previously treated adults with relapsed or refractory multiple myeloma

This phase 1 study investigated the safety of the anthracycline amrubicin combined with lenalidomide and dexamethasone in adults with relapsed or refractory multiple myeloma. A standard 3 + 3 design was used. Patients received intravenous amrubicin 40-80 mg/m² on day one, lenalidomide 15 mg orally on days 1-14, and dexamethasone 40 mg orally weekly on 21 day cycles. 14 patients were enrolled, and completed a median of three cycles. The maximum tolerated dose was not reached. One patient experienced dose limiting toxicity of dizziness and diarrhea. The most frequent non-hematologic toxicity was infection (79%). Serious adverse events included cord compression and sepsis. Three patients (21%) had a partial response or better, and seven (50%) had stable disease. The median duration of response was 4.4 months, and the median progression-free survival was 3 months. Amrubicin combined with lenalidomide and dexamethasone, was safe and demonstrated clinical activity in relapsed or refractory multiple myeloma.Clinicaltrials.gov identifier: NCT01355705.

Autoimmune diseases, infections, use of antibiotics and the risk of acute myeloid leukaemia: a national population-based case-control study

Previous studies reported increased risk of acute myeloid leukaemia (AML) in individuals with inflammatory conditions. However, it is unclear whether this association is explained by preceding cytotoxic therapy or haematological diseases. We conducted a nationwide case-control study that included 3053 AML patients, diagnosed in Denmark between 2000 and 2013, and 30 530 sex- and age-matched population controls. We retrieved information on autoimmune disease, infections, and use of antibiotics and computed odds ratios for AML (conditional logistic regression). Results were stratified by AML type, sex, and age. Autoimmune diseases were associated with an overall increased risk of AML {odds ratio [OR] 1·3 [95% confidence interval (CI) = 1·1-1·5]}. However, the risk was confined to patients with previous haematological disease or cytotoxic therapy exposure [secondary/therapy-related AML (sAML/tAML0) OR 2·0 (95% CI = 1·6-2·6)] and not de novo AML [OR 1·1 (95% CI = 0·9-1·3)]. Similarly, any prior infection requiring hospitalization was associated with a higher risk of AML [OR 1·3 (95% CI = 1·1-1·4)]. Again, this association was evident for sAML/tAML [OR 1·8 (95% CI = 1·5-2·2)], and not de novo AML [OR 1·1 (95% CI = 1·0-1·2)]. In conclusion, autoimmune diseases and infections were associated with an increased AML risk only in subjects with prior haematological disease and/or cytotoxic treatment. These observations suggest, that inflammation plays - if any - a minor role for the development of de novo AML.

Autophagy mediates proteolysis of NPM1 and HEXIM1 and sensitivity to BET inhibition in AML cells

The mechanisms underlying activation of the BET pathway in AML cells remain poorly understood. We have discovered that autophagy is activated in acute leukemia cells expressing mutant nucleophosmin 1 (NPMc+) or MLL-fusion proteins. Autophagy activation results in the degradation of NPM1 and HEXIM1, two negative regulators of BET pathway activation. Inhibition of autophagy with pharmacologic inhibitors or through knocking down autophagy-related gene 5 (Atg5) expression increases the expression of both NPM1 and HEXIM1. The Brd4 inhibitors JQ1 and I-BET-151 also inhibit autophagy and increase NPM1 and HEXIM1 expression. We conclude that the degradation of NPM1 and HEXIM1 through autophagy in certain AML subsets contributes to the activation of the BET pathway in these cells.

Interpretation of clinical endpoints in trials of acute myeloid leukemia

Treatment regimens for acute myeloid leukemia (AML) have remained largely unchanged until recently. Molecular advances have opened the door to targeted therapies, many of which are in late-phase clinical trials. As new therapeutic opportunities arise, it is appropriate to review key aspects of clinical trial design, statistical interpretation of outcomes, and methods of data reporting. Complete remission and overall survival (OS) are common primary endpoints in early-phase AML clinical trials. OS and event-free survival are frequent primary endpoints in phase 3 trials. Clinical trials are designed to address the primary endpoint using prespecified α and power levels. Interpretation of additional endpoints (eg, secondary endpoints and subgroup analyses) must be viewed in light of a trial's statistical design. Furthermore, variations in reporting of endpoints must be considered in order to understand trial outcomes. Time-to-event endpoints are typically reported using Kaplan-Meier curves, which are visually informative. Statistical data derived from these curves can be complex, and a variety of factors may impact interpretation. The purpose of this review is to discuss the nuances of common AML trial endpoints and their data presentation to better inform evaluation and understanding of clinical trial data.

Report of the relapsed/refractory cohort of SWOG S0919: A phase 2 study of idarubicin and cytarabine in combination with pravastatin for acute myelogenous leukemia (AML)

Inhibition of cholesterol synthesis and uptake sensitizes acute myeloid leukemia (AML) blasts to chemotherapy. A Phase 2 study of high dose pravastatin given in combination with idarubicin and cytarabine demonstrated an impressive response rate [75% complete remission (CR), CR with incomplete count recovery (CRi)]. However, this population was a favorable risk group as eligible patients had to have a CR/CRi lasting ≥3 months following their most recent chemotherapy. Therefore, the study was amended to treat patients with poor risk disease including those with CR/CRi <6 months following their last induction regimen or with refractory disease. Here, we present results in this poor risk group. This trial included a significant number of patients with poor risk cytogenetics (43%) and poor risk molecular mutations. The response rate was 30% and approximately one-fourth of patients were able to proceed to allogeneic hematopoietic stem cell transplant (HSCT). The median overall survival for patients proceeding to allogeneic HSCT is 27.1 months. Although this trial did not meet criteria for a positive study based on the response rate (p = .062), these results are encouraging given the poor risk population and suggest that targeting the cholesterol pathway may have therapeutic benefit in AML.

Novel Therapeutics in Acute Myeloid Leukemia

In this review, we focus on three key areas in acute myeloid leukemia (AML) developmental therapeutics: FLT3 inhibitors, IDH inhibitors, and drugs that may be particularly beneficial in secondary AML.

Identification of Interleukin-1 by Functional Screening as a Key Mediator of Cellular Expansion and Disease Progression in Acute Myeloid Leukemia

Secreted proteins in the bone marrow microenvironment play critical roles in acute myeloid leukemia (AML). Through an ex vivo functional screen of 94 cytokines, we identified that the pro-inflammatory cytokine interleukin-1 (IL-1) elicited profound expansion of myeloid progenitors in ∼67% of AML patients while suppressing the growth of normal progenitors. Levels of IL-1β and IL-1 receptors were increased in AML patients, and silencing of the IL-1 receptor led to significant suppression of clonogenicity and in vivo disease progression. IL-1 promoted AML cell growth by enhancing p38MAPK phosphorylation and promoting secretion of various other growth factors and inflammatory cytokines. Treatment with p38MAPK inhibitors reversed these effects and recovered normal CD34⁺ cells from IL-1-mediated growth suppression. These results highlight the importance of ex vivo functional screening to identify common and actionable extrinsic pathways in genetically heterogeneous malignancies and provide impetus for clinical development of IL-1/IL1R1/p38MAPK pathway-targeted therapies in AML.