CAR T-Cells for the Treatment of B-Cell Acute Lymphoblastic Leukemia

B-cell acute lymphoblastic leukemia (B-ALL) is the most common subtype of acute leukemia in the pediatric population. The prognosis and treatment of B-ALL have dramatically improved over the past decade with the adoption of intensive and prolonged combination chemotherapy regimens. The advent of novel immunologic agents such as blinatumomab and inotuzumab has changed the treatment landscape of B-ALL. However, patients have continued to relapse, raising the need for novel therapies. Chimeric antigen receptor (CAR) T-cells have achieved a milestone in the treatment of B-ALL. Two CD19-targeting CAR T-cells were approved by the Food and Drug Administration and the European Medicines Agency for the treatment of relapsed and/or refractory B-ALL. In this review, we review the available data regarding CD19-targeting CAR T-cells with their safety profile as well as the mechanism of resistance to these agents and the way to overcome this resistance.

Enasidenib treatment in two individuals with D-2-hydroxyglutaric aciduria carrying a germline IDH2 mutation

D-2-hydroxyglutaric aciduria type II (D2HGA2) is a severe inborn disorder of metabolism caused by heterozygous R140 mutations in the IDH2 (isocitrate dehydrogenase 2) gene. Here we report the results of treatment of two children with D2HGA2, one of whom exhibited severe dilated cardiomyopathy, with the selective mutant IDH2 enzyme inhibitor enasidenib. In both children, enasidenib treatment led to normalization of D-2-hydroxyglutarate (D-2-HG) concentrations in body fluids. At doses of 50 mg and 60 mg per day, no side effects were observed, except for asymptomatic hyperbilirubinemia. For the child with cardiomyopathy, chronic D-2-HG inhibition was associated with improved cardiac function, and for both children, therapy was associated with improved daily functioning, global motility and social interactions. Treatment of the child with cardiomyopathy led to therapy-coordinated changes in serum phospholipid levels, which were partly recapitulated in cultured fibroblasts, associated with complex effects on lipid and redox-related gene pathways. These findings indicate that targeted inhibition of a mutant enzyme can partly reverse the pathology of a chronic neurometabolic genetic disorder.

Ivosidenib in patients with IDH1-mutant relapsed/refractory myelodysplastic syndrome (R/R MDS): Updated enrollment and results of a phase 1 dose-escalation and expansion substudy

7053

Background: Mutations in isocitrate dehydrogenase 1 ( IDH1) occur in ̃3% of patients (pts) with MDS and are associated with increased transformation to acute myeloid leukemia (AML). Ivosidenib (IVO), an oral, potent, targeted inhibitor of the mutant IDH1 (mIDH1) enzyme, is FDA approved for m IDH1 R/R AML and m IDH1 newly diagnosed AML in pts ≥75 years old or with comorbidities precluding the use of intensive induction chemotherapy. In the first-in-human study of IVO in pts with m IDH1 advanced hematologic malignancies (NCT02074839), 12 pts with R/R MDS received IVO 500 mg once daily (QD). Based on encouraging safety and efficacy findings, including an investigator-assessed overall response rate (ORR) of 75%, with median response duration of 21.4 months, the FDA granted Breakthrough Therapy designation to IVO in m IDH1 R/R MDS and the study was amended to enroll additional pts. We report updated results. Methods: This substudy of the single-arm, open-label study of IVO evaluated pts with R/R MDS after documented failure or relapse following prior standard therapy including intensive chemotherapy and hypomethylating agents. Other key eligibility criteria included: high disease burden based on IPSS or IPSS-R risk at baseline; an Eastern Cooperative Oncology Group performance status score of 0–2; and no prior IDH1 inhibitor therapy. Pts received IVO 500 mg QD orally on days 1–28 of 28-day cycles. Results: As of 08May2021, 16 pts with R/R MDS were enrolled: 5 (31%) pts remained on treatment and free from leukemic transformation; 11 (69%) had discontinued including 6 for disease progression, 1 for allogeneic stem cell transplantation, and 1 owing to an adverse event (AE) of sepsis (the only fatal AE; reported by investigator as not related to IVO). AEs are summarized in the Table. 2 pts each experienced differentiation syndrome (grade 2) and QTcF prolongation (grade 1 and 2). 7/16 pts achieved complete response (CR, 44%; 95% CI, 20%, 70%), 1 achieved partial response (6%), and 5 achieved marrow CR (31%), resulting in an ORR of 81% (95% CI, 54%, 96%). Hematologic improvement in ≥1 lineages was achieved by 11/16 (69%) pts. The Kaplan-Meier estimate of duration of CR+PR at 12 months was 60%. 3 pts experienced CRs lasting 24.0, 63.7, and 65.4 months, which remain ongoing. 5/7 pts (71%) who were transfusion dependent at baseline became independent of red blood cell or platelet transfusions for 56 or more consecutive days on treatment. Additional translational data are being analyzed. Conclusions: In pts with m IDH1 R/R MDS, IVO monotherapy was tolerable and induced durable remissions and transfusion independence. These findings support the role of IVO as an effective, oral, targeted treatment for pts with m IDH1 R/R MDS. Clinical trial information: NCT02074839. [Table: see text]

Health-related quality of life (HRQoL) with enasidenib versus conventional care regimens in older patients with late-stage mutant-IDH2 relapsed or refractory acute myeloid leukemia (R/R AML)

7032

Background: Enasidenib (ENA) is an oral inhibitor of mutant-IDH2 (mIDH2) proteins. In the phase 3 IDHENTIFY trial, ENA improved event-free survival (EFS), overall response, and complete remission rate vs conventional care regimens (CCR) ( P < 0.01 for all) in patients (pts) ≥ 60 years of age with m IDH2 R/R AML with 2 or 3 prior treatments (Tx) (DiNardo 2021). Pt-reported HRQoL was a secondary trial endpoint. Methods: IDHENTIFY is an open-label, randomized trial (NCT02577406). Pts were preselected to a CCR (SC azacitidine, intermediate- or low-dose Ara-C, or supportive care) and then randomized 1:1 to ENA 100 mg/d or CCR in 28-d cycles. Key HRQoL endpoints were mean changes from baseline (CFB) overall and by clinical response in the Global Health Status/QoL, Physical Functioning, Role Functioning, Fatigue, and Dyspnea domains of the EORTC QLQ-C30 questionnaire, and in EQ-5D-5L utility index (UI) and visual analogue scale scores. The QLQ-C30 and EQ-5D-5L were assessed on D1 of each Tx cycle (C) and at end of Tx. Minimally important differences (MIDs) in CFB scores within or between Tx arms were based on accepted thresholds. Sensitivity analysis using imputed data on CFB was conducted using pattern mixture modeling. Results: HRQoL-evaluable cohorts included 118/158 (74.7%) pts in the ENA arm and 80/161 (49.7%) in the CCR arm; 40 ENA pts and 81 CCR pts were not evaluable due to missing data at baseline (BL; 22 ENA and 51 CCR) and/or at ≥1 post-BL visit (26 ENA and 69 CCR). Pts ineligible for HRQoL analyses had lower response rates and worse EFS and overall survival than HRQoL-evaluable pts. Overall QLQ-C30 completion rates in the ENA and CCR arms were 79% and 65%, respectively ( P < 0.001). While there was no meaningful improvement or worsening from BL (ie, exceeding MID) within either Tx arm in the key QLQ-C30 domains, scores worsened during initial Tx cycles and then improved with continued Tx. Mean EQ-5D-5L scores also worsened during early cycles in both Tx arms, with meaningful UI deterioration in the ENA arm from C2 through C7. However, between-group comparisons showed no consistent differences between ENA and CCR in mean CFB. Sensitivity analysis with imputation of missing CFB data showed worsened HRQoL compared with non-imputed data in the CCR arm but not with ENA. In the ENA arm, clinical responders reported relatively stable mean HRQoL scores over time, and non-responders showed no meaningful differences in CFB vs the CCR arm. Conclusions: HRQoL measures tended to worsen during early cycles in both Tx arms and gradually improved with continued Tx. Data should be interpreted with caution as only approximately one-half of pts in the CCR arm were HRQoL-evaluable. ENA improved clinical efficacy measures vs CCR without compromising HRQoL in older pts with R/R AML. Clinical trial information: NCT02577406.

Tamibarotene in combination with venetoclax and azacitidine in previously untreated adult patients selected for RARA-positive AML who are ineligible for standard induction therapy (SELECT AML-1)

TPS7065

Background: RARA-positive (RARA+) AML is a novel genomically defined patient subset with an actionable biological target for treatment with tamibarotene, an oral and selective RARα agonist (McKeown 2017). RARA+ patients can be selected by a blood-based biomarker test, with approximately 30% of newly diagnosed (ND) AML patients being RARA+ (Vigil 2017). As a biologically targeted agent for patients with RARA overexpression, tamibarotene has the potential to provide benefit irrespective of mutation or cytogenetic risk classification. In RARA+ ND AML patients ineligible for standard induction therapy, tamibarotene plus azacitidine (aza) led to a CR/CRi rate of 61% and a rapid onset of response (de Botton 2020). Approximately one-third of patients with ND unfit AML do not respond to front-line standard of care venetoclax (ven)/aza (DiNardo 2020). Translational data suggest RARA positivity enriches for monocytic features reported to be associated with ven resistance (Fiore 2020, Pei 2020). This data suggests the RARA biomarker selects for patients who may respond to tamibarotene and may be less likely to respond to ven/aza. Given that tamibarotene plus aza has been generally well tolerated, with no increase in myelosuppression compared to single agent aza (de Botton 2020), it is anticipated that tamibarotene can be administered safely in combination with ven/aza. Methods: This is a Phase 2, open-label, multi-center study in the U.S. and France comparing the clinical activity of tamibarotene/ven/aza to ven/aza in treatment-naive RARA+ AML patients ineligible for standard induction chemotherapy. The primary objectives are to characterize the safety of the combination and to compare the CR/CRi rate of tamibarotene/ven/aza vs. ven/aza, with secondary objectives to compare CR rate, CR/CRh rate, duration of response, and time to response. The overall response rate using tamibarotene/ven/aza following ven/aza treatment failure will be explored. Clinical activity will be characterized by ELN criteria (Dohner 2017). This 3-part trial includes a safety lead-in, randomized efficacy study, and salvage arm. Following the safety lead-in, approximately 80 patients will be randomized 1:1 to receive tamibarotene/ven/aza or ven/aza. Response rates and 95% exact binomial confidence intervals will be calculated by treatment group. In the salvage arm, tamibarotene will be added for study patients randomized to ven/aza who experience progressive disease, relapse, or treatment failure. Patients will be treated with aza at 75 mg/m2 IV/SC daily on days 1-7, ven on days 1-28 per VENCLEXA USPI, followed by tamibarotene at 6 mg twice per day by mouth on days 8-28 of each 28-day cycle. The SELECT AML-1 trial opened in July 2021 with ongoing enrollment. Clinical trial information: NCT04905407.

Hematologic improvements with ivosidenib + azacitidine compared to placebo + azacitidine in patients with newly diagnosed acute myeloid leukemia

7042

Background: Ivosidenib (IVO) is a potent oral targeted inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1). IVO plus azacitidine (AZA) significantly improved event-free survival (EFS), overall survival and complete remission + partial hematologic recovery rates compared with placebo (PBO) + AZA, in patients (pts) with newly diagnosed IDH1-mutant acute myeloid leukemia (AML) in the Phase 3 AGILE trial (NCT03173248). Here we report blood count recovery results from the AGILE trial. Methods: Pts were randomized 1:1 to IVO 500 mg QD + AZA 75 mg/m2 SC or IV for 7 days in 28-day cycles (n = 72), or PBO+AZA (n = 74). Red blood cell (RBC)/platelet transfusion history were assessed at screening and follow-up. Bone marrow (BM) and peripheral blood samples were obtained at screening, and during weeks 9, 17, 25, 33, 41, 53, and every 24 weeks thereafter, and at end of treatment and during EFS follow up. Samples were analyzed at each local site according to ICSH guidelines. Results: In the IVO+AZA and PBO+AZA arms, 4.2% and 5.5% of pts, respectively, received concomitant granulocyte colony-stimulating factor. Hemoglobin levels steadily increased from baseline at a similar rate in both treatment arms. Mean platelet count recovered from baseline values in the IVO+AZA and PBO+AZA arms (71.0 and 92.6 x 109/L, respectively) as early as week 9 of treatment (171.1 and 155.1 x 109/L, respectively) and continued to steadily increase thereafter in the treated population. In pts receiving IVO+AZA, mean neutrophil counts rapidly increased from baseline (0.99 x 109/L) to week 2 (2.05 x 109/L) and week 5 (4.07 x 109/L), and then generally stabilized to within the normal range to study end (last available cycle value; ̃2.0 x 109/L). Mean neutrophil counts initially declined with PBO+AZA before slowly recovering to near-normal levels after 36-40 weeks. The increased blood counts were accompanied by a rapid decrease in the mean BM blast percentage from 54.8% at baseline to 12.0% and 7.2% at week 9 and 17, respectively, in IVO+AZA treated patients and were maintained for 149 weeks. The decline in BM blasts was slower in the PBO+AZA arm (53.7%, 34.6% and 19.6% at baseline, week 9 and week 17, respectively). Among patients who were RBC/platelet transfusion-dependent at baseline (̃54.0% in both groups), 46.2% in the IVO+AZA group achieved RBC/platelet transfusion independence compared with 17.5% in the PBO+AZA arm (1-sided p = 0.0032). Additionally, fewer adverse events of febrile neutropenia (28.2% vs 34.2%) and infections (28.2% vs 49.3%) were reported in the IVO+AZA arm compared to the PBO+AZA arm. Conclusions: IVO+AZA demonstrated a significant clinical benefit compared with PBO+AZA and this sub-analysis demonstrated a rapidly improved recovery of blood counts and a reduced dependence on RBC and/or platelet transfusion. Moreover, rates of febrile neutropenia and infections were reduced with IVO+AZA. Clinical trial information: NCT03173248.

Changes in health-related quality of life in patients with newly diagnosed acute myeloid leukemia receiving ivosidenib + azacitidine or placebo + azacitidine

e19024

Background: Ivosidenib (IVO) is a potent, targeted inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1) that is approved for acute myeloid leukemia (AML). IVO plus azacitidine (AZA) demonstrated clinical benefit compared with placebo (PBO) and AZA in the AGILE study (NCT03173248), and here we report the impact of IVO+AZA versus PBO+AZA on health-related quality of life (HRQoL). Methods: In the double-blind, PBO-controlled phase 3 AGILE study, patients (pts) were randomized 1:1 to IVO 500 mg QD + AZA 75 mg/m2 SC or IV for 7 days in 28-day cycles, or PBO+AZA. HRQoL was a secondary endpoint assessed using two validated questionnaires: the European Organisation of Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30) and the EuroQol 5-dimension 5-level questionnaire (EQ-5D-5L). Questionnaires were administered pre-dose on cycle (C) 1 Day (D) 1, on C1D15, C2D1, C2D15, and on D1 of every odd cycle thereafter until the end of treatment. Score change from baseline across visits for all subscales of EORTC QLQ-C30 was analyzed with mixed models. A 10-point threshold in EORTC QLQ-C30 subscale score was used to evaluate clinically meaningful changes from baseline or differences between arms. Two-sided nominal p-values are reported. Results: At baseline, 69 and 68 pts out of 72 receiving IVO+AZA completed the EORTC QLQ-C30 and EQ-5D-5L, respectively, and 66 pts out of 74 receiving PBO+AZA completed both. Mean baseline HRQoL scores were similar between treatment arms. There was an initial decline in HRQoL (EORTC QLQ-C30 global health status [GHS/QoL]) in both arms for ̃4 months, consistent with time to response, and which was generally not clinically meaningful. IVO+AZA was associated with preserved or improved HRQoL compared to baseline for most subscales of the EORTC QLQ-C30 from C5 to C19 (after which no PBO+AZA HRQoL data were available), and at most timepoints for EQ-5D-5L VAS scores and index values. EORTC QLQ-C30 subscales with clinically meaningful improvements from baseline at most timepoints from C5 to C19 in the IVO+AZA arm included GHS/QoL, fatigue, pain and appetite loss. In contrast, there were few clinically meaningful improvements from baseline in PBO+AZA pts. GHS/QoL scores were significantly improved (p≤0.05) for IVO+AZA versus PBO+AZA at C2D1, C2D15, C7 and C9, and differences were clinically meaningful at C2D1 (10.2 point difference), C2D15 (10.1), C7 (12.6), C9 (22.6), C13 (14.9), C15 (15.4) and C19 (19.2). Likewise, improvements in EORTC QLQ-C30 fatigue, appetite loss, nausea and vomiting, diarrhea, cognitive functioning and social functioning favored IVO+AZA over PBO+AZA at multiple timepoints. Conclusions: Data from the AGILE study show that patients with mIDH1 AML receiving treatment with IVO+AZA tended to report maintenance or improved HRQoL from cycle 5 through to cycle 19 compared with PBO+AZA. Clinical trial information: NCT03173248.

Molecular characterization of clinical response in patients with newly diagnosed acute myeloid leukemia treated with ivosidenib + azacitidine compared to placebo + azacitidine

7019

Background: Acute myeloid leukemia (AML) is a disease with a dynamic mutational landscape; 6–10% of patients (pts) have somatic mutations in isocitrate dehydrogenase 1 ( IDH1), which can drive oncogenesis. Ivosidenib (IVO) is a potent oral targeted inhibitor of mutant IDH1 (mIDH1). IVO 500 mg QD + azacitidine (AZA) 75 mg/m2 SC or IV for 7 days in 28-day cycles was shown to significantly improve event-free survival (HR = 0.33 [95% CI 0.16, 0.69], p = 0.0011), median overall survival (24.0 vs 7.9 months), and complete remission + partial hematologic recovery rates (CR/CRh; 52.8% vs 17.6%) vs placebo (PBO) + AZA in the double-blind phase 3 AGILE study (NCT03173248) in pts with newly diagnosed IDH1-mutated AML (ND-AML). IDH1-mutation clearance ( IDH1-MC) and baseline co-mutation analysis from AGILE is reported. Methods: Genomic DNA from bone marrow mononuclear cells (BMMCs) or peripheral blood mononuclear cells (PBMCs), and/or bone marrow aspirate (BMA) were used for molecular studies. IDH1-MC analysis on BMMCs was performed by BEAMing digital PCR (limit of detection 0.02%-0.04%). BMA, BMMCs and PBMCs were utilized for co-mutational analysis by next-generation sequencing, ACE Extended Cancer Panel (detection limit 2%). Results: 146 pts were randomized: 72 to IVO+AZA; 74 to PBO+AZA. Median (range) baseline m IDH1 variant allele frequency in BMMCs was 36.7% (3.1–50.5) in the IVO+AZA arm and 35.5% (3.0–48.6) in the PBO+AZA arm. Updated IDH1-MC data (October 2021) from 47 IVO+AZA and 32 PBO+AZA treated pts with at least 1 on-treatment sample demonstrated IDH1-MC in 21/35 (60%) IVO+AZA pts achieving CR/CRh vs 4/11 (36%) PBO+AZA pts. In CR/CRh pts with time points available after IDH1-MC, suppression of the m IDH1 was durable and IDH1-MC maintained in all subsequent samples in 17/17 (100%) IVO+AZA treated pts and 1/3 (33%) PBO+AZA pts. Further analysis of baseline co-mutations on 120 pts (IVO+AZA: n = 58; PBO+AZA: n = 62) showed that DNMT3A, SRSF2, and RUNX1 were the most frequent in both treatment arms. Importantly, comparison of CR/CRh and non CR/CRh responses by cohort did not identify any single gene or pathway associated with an inferior outcome in IVO+AZA pts compared to PBO+AZA pts (p < 0.05, Fisher’s Exact test). Several genes ( DNMT3A, RUNX1, SRSF2, STAG2) and pathways (Differentiation, Epigenetics, Splicing) were associated with improved outcomes with IVO+AZA, including the RTK pathway, which was previously reported to be associated with primary resistance to IVO monotherapy. Further analysis of patient subgroups, including R132 variants (i.e., R132C vs R132S), will be presented. Conclusions: These data suggest that improved clinical outcomes with IVO+AZA are associated with sustained clearance of the m IDH1 clone including pts with disease that harbor mutations implicated in resistance to IVO monotherapy (e.g., with RTK pathway mutations). Clinical trial information: NCT03173248.

Overall survival by IDH2 mutant allele (R140 or R172) in patients with late-stage mutant-IDH2 relapsed or refractory acute myeloid leukemia treated with enasidenib or conventional care regimens in the phase 3 IDHENTIFY trial

7005

Background: IDH2 gene mutations (m IDH2) occur in up to ̃20% of patients (pts) with acute myeloid leukemia (AML), most commonly as R140Q (in ̃75% of cases) or R172K (̃25%) point mutations. The functional effects and prognostic relevance of m IDH2-R140 and m IDH2-R172 can vary (Papaemmanuil 2016). In the randomized, phase 3 IDHENTIFY trial, enasidenib (ENA), an oral mIDH2 inhibitor, did not significantly improve overall survival (OS) vs conventional care regimens (CCR) as salvage treatment (Tx) for older pts with m IDH2 relapsed/refractory (R/R) AML in ITT analysis, but a trend for improved OS with ENA was detected in pts with IDH2-R172 mutations. We further investigated OS and correlative biomarkers in IDHENTIFY pt subgroups defined by m IDH2 variant (R140/R172). Methods: This open-label trial (NCT02577406) enrolled pts ≥ 60 years of age who had received 2 or 3 prior AML Tx. Pts were preselected to a CCR (azacitidine, intermediate- or low-dose Ara-C, or supportive care), and were then randomized 1:1 to ENA 100 mg/d or CCR in 28d cycles. Co-occurring gene mutations were identified by targeted next-generation sequencing (37-gene panel) of bone marrow mononuclear cell (BMMC) DNA. Total 2-HG levels were determined by LC/MS. Results: Of 319 pts enrolled, 88 pts (28%; 43 ENA, 45 CCR) had m IDH2-R172 and 229 (72%; 115 ENA, 114 CCR) had m IDH2-R140. Median baseline (BL) 2-HG levels were similar between Tx arms and m IDH2 variant subgroups, as were IDH2 variant allele frequencies. Pts with m IDH2-R172 had fewer median BL co-mutations (4 [range 2–8]) than did pts with m IDH2-R140 (5 [1–11]) ( P < 0.0001). The most frequently co-occurring mutations were SRSF2 and RUNX1 in the R140 cohort (59% each) and DNMT3A in the R172 cohort (57%). Compared with the R172 cohort, the R140 group was enriched with SRSF2, FLT3 (-ITD/-TKD), NPM1, RUNX1, and JAK2 mutations, whereas DNMT3A and TP53 mutations were more common in the R172 group. In Cox multivariate analysis including m IDH2 variant (R140/R172), DNMT3A mutation status, and number of gene mutations at BL, m IDH2-R172 was significantly ( P = 0.04) correlated with improved OS (vs. R140) in the ENA arm, whereas the number of BL gene mutations was significantly ( P < 0.01) associated with OS in the CCR arm. Median OS in the R172 subgroup was 14.6 mo with ENA vs 7.8 mo with CCR (HR, 0.59 [95%CI 0.35-0.98]; P = 0.039) and 1-yr survival rates were 62% and 30%, respectively. In m IDH2-R140 pts, median OS was 5.7 mo in both Tx arms (0.93 [0.70-1.24]; P = 0.61), and 1-year survival rates were 29% and 25% with ENA and CCR, respectively. Conclusions: Mutational burden and co-mutational profiles differed between pts with m IDH2-R140 and m IDH2-R172 R/R AML. ENA improved survival outcomes for pts with IDH2-R172 mutations, with median OS and 1-year survival rate approximately double those in the CCR arm. Clinical trial information: NCT02577406.

Minimal residual disease monitoring in acute myeloid leukemia with non-A/B/D-NPM1 mutations by digital polymerase chain reaction: feasibility and clinical use

Not available.

Effect of olutasidenib (FT-2102) on complete remissions in patients with relapsed/refractory (R/R) mIDH1 acute myeloid leukemia (AML): Results from a planned interim analysis of a phase 2 clinical trial

7006

Background: Olutasidenib, a potent, selective, oral, small molecule inhibitor of mutant IDH1 (m IDH1), has exhibited favorable tolerability and clinical activity in high-risk AML patients (pts) in a phase 1 trial (Watts, Blood 2019). Here, we present interim analysis results of a phase 2 trial (NCT02719574) in R/R m IDH1 AML pts receiving olutasidenib monotherapy 150 mg twice daily. Methods: The efficacy evaluable (EE) set comprised m IDH1R132X pts whose first dose was ≥180 days before the data cut-off (18-JUN-20). The primary endpoint was CR+CRh (complete remission [CR] or CR with partial hematologic recovery [CRh] according to modified IWG 2003 criteria) rate. CRh was defined as bone marrow blasts <5%, absolute neutrophil count >0.5×109/L, and platelet count >50×109/L. Overall response rate (ORR) comprised CR+CRh+CR with incomplete recovery (CRi) + morphologic leukemia-free state (MLFS) + partial response (PR). Duration of treatment (DOT), duration of response (DOR), and overall survival (OS) were estimated using Kaplan-Meier methodology. Results: This clinical trial met its pre-specified early enrollment-stopping criteria for efficacy. A total of 153 pts with R/R AML received olutasidenib; median DOT, 5.5 mo (95% CI: 4.4, 8.7). 43 pts (28%) remain on treatment and 110 (72%) discontinued, most commonly due to: disease progression, 31%; AEs, 14%; death, 10%; and transplant, 8%. For the EE set (123 pts), the median age was 71 y (range: 32‒87) with a median number of prior therapies of 2 (1‒7). The CR+CRh rate was 33% including 30% of pts in CR (Table). Median duration of CR+CRh was not reached (NR) and 13.8 mo in a sensitivity analysis when HSCT or relapse was deemed end of response. ORR was 46% and median duration of ORR was 11.7 mo. Of responders who were transfusion-dependent at baseline, 56-day platelet transfusion independence (TI) and RBC TI were gained by 100% and 83%, respectively, of pts who achieved CR+CRh, and by 56% and 50% who did not. Median OS was 10.5 mo (EE set). In CR+CRh responders, median OS was NR and the estimated 18-mo OS was 87%. TEAEs in ≥25% of pts were nausea, 38%; constipation, 25%; leukocytosis, 25%. Grade 3/4 all-causality TEAEs in >10% of pts were febrile neutropenia, 20%; anemia, 19%; thrombocytopenia, 16%; neutropenia, 13%. Investigator-assessed IDH1 differentiation syndrome (any grade) was observed in 21 pts (14%); most cases resolved with treatment management; one case was fatal; 19 pts had concomitant leukocytosis. Conclusions: Olutasidenib was well tolerated and induced durable CR in a subset of high-risk R/R m IDH1 AML pts. TI was achieved in all response groups. Clinical benefit, per DOR and OS, extended beyond CR+CRh responders. Clinical trial information: NCT02719574. [Table: see text]

Avadomide induces degradation of ZMYM2 fusion oncoproteins in hematologic malignancies

Thalidomide analogs exert their therapeutic effects by binding to the CRL4^CRBN E3 ubiquitin ligase, promoting ubiquitination and subsequent proteasomal degradation of specific protein substrates. Drug-induced degradation of IKZF1 and IKZF3 in B-cell malignancies demonstrates the clinical utility of targeting disease-relevant transcription factors for degradation. Here, we found that avadomide (CC-122) induces CRBN-dependent ubiquitination and proteasomal degradation of ZMYM2 (ZNF198), a transcription factor involved in balanced chromosomal rearrangements with FGFR1 and FLT3 in aggressive forms of hematologic malignancies. The minimal drug-responsive element of ZMYM2 is a zinc-chelating MYM domain and is contained in the N-terminal portion of ZMYM2 that is universally included in the derived fusion proteins. We demonstrate that avadomide has the ability to induce proteasomal degradation of ZMYM2-FGFR1 and ZMYM2-FLT3 chimeric oncoproteins, both in vitro and in vivo. Our findings suggest that patients with hematologic malignancies harboring these ZMYM2 fusion proteins may benefit from avadomide treatment.

Impact and consequences of intensive chemotherapy on intestinal barrier and microbiota in acute myeloid leukemia: the role of mucosal strengthening

Induction chemotherapy (7 + 3 regimen) remains the gold standard for patients with acute myeloid leukemia (AML) but is responsible for gut damage leading to several complications such as bloodstream infection (BSI). We aimed to investigate the impact of induction chemotherapy on the intestinal barrier of patients with AML and in wild-type mice. Next, we assessed the potential benefit of strengthening the mucosal barrier in transgenic mice releasing a recombinant protein able to reinforce the mucus layer (Tg222). In patients, we observed a decrease of plasma citrulline, which is a marker of the functional enterocyte mass, of short-chain fatty acids and of fecal bacterial load, except for Escherichia coli and Enterococcus spp., which became dominant. Both the α and β-diversities of fecal microbiota decreased. In wild-type mice, citrulline levels decreased under chemotherapy along with an increase of E. coli and Enterococcus spp load associated with concomitant histologic impairment. By comparison with wild-type mice, Tg222 mice, 3 days after completing chemotherapy, had higher citrulline levels, a faster healing epithelium, and preserved α-diversity of their intestinal microbiota. This was associated with reduced bacterial translocations. Our results highlight the intestinal damage and the dysbiosis induced by the 7 + 3 regimen. As a proof of concept, our transgenic model suggests that strengthening the intestinal barrier is a promising approach to limit BSI and improve AML patients' outcome.

Azacytidine in combination with tyrosine kinase inhibitors induced durable responses in patients with advanced phase chronic myelogenous leukemia

Although the tyrosine kinase inhibitor (TKI) era has brought great improvement in outcome in chronic myelogenous leukemia (CML), prognosis of accelerated phase or myeloid blast crisis patients or of de novo Philadelphia chromosome-positive acute myeloid leukemia remains poor. We conducted a retrospective study on patients with advanced phase disease treated with a TKI and azacytidine. Sixteen patients were eligible. Median age was 64.9 years, the median number of previous therapies was 2.5 lines, and median follow-up was 23.1 months. Hematologic response (HR) rate was 81.3%. Median overall survival (OS), event free survival and relapse-free survival (RFS) were 31.5, 23.3, and 32.2 months, respectively. All except one patient were treated as out-patients after the first cycle. Five patients were bridged to allogenic hematopoietic stem cells transplant. The combination of a TKI and azacytidine is a safe and efficient regiment for patients with CML patients in advanced phases.

Quantitation of isocitrate dehydrogenase (IDH)-induced D and L enantiomers of 2-hydroxyglutaric acid in biological fluids by a fully validated liquid tandem mass spectrometry method, suitable for clinical applications

A recent update of the hallmarks of cancer includes metabolism with deregulating cellular energetics. Activating mutations in isocitrate dehydrogenase (IDH) metabolic enzymes leading to the abnormal accumulation of 2-hydroxyglutaric acid (2-HGA) have been described in hematologic malignancies and solid tumours. The diagnostic value of 2-HGA levels in blood to identify IDH mutations and its prognostic significance have been reported. We developed a liquid chromatography tandem mass spectrometry method allowing a rapid, accurate and precise simultaneous quantification of both L and D enantiomers of 2-HGA in blood samples from acute myeloid leukaemia (AML) patients, suitable for clinical applications. The method was also develop for preclinical applications from cellular and tissues samples. Deuterated (R,S)-2-hydroxyglutaric acid, disodium salt was used as internal standard and added to samples before a solid phase extraction on Phenomenex STRATA™-XL-A (200mg-3mL) 33μm cartridges. A derivatization step with (+)- o,o'-diacetyl-l-tartaric anhydride permitted to separate the two resulting diastereoisomers without chiral stationary phase, on a C18 column combined to a Xevo TQ-MS Waters mass spectrometer with an electrospray ionization (ESI) source. This method allows standard curves to be linear over the range 0.34-135.04μM with r(2) values>0.999 and low matrix effects (<11.7%). This method, which was validated according to current EMA guidelines, is accurate between-run (<3.1%) and within-run (<7.9%) and precise between-run (<5.3CV%) and within-run (<6.2CV%), and is suitable for clinical and preclinical applications.

Hyperferritinemia at diagnosis predicts relapse and overall survival in younger AML patients with intermediate-risk cytogenetics

The prognostic value of ferritin level at diagnosis in AML patients is unknown. We studied 162 younger AML patients with intermediate-risk cytogenetics who received intensive chemotherapy. The median ferritin level at diagnosis was 633 μg/L and 128 (79%) patients had a ferritin level above the upper normal limit. Hyperferritinemia was significantly associated with a higher cumulative incidence of relapse as well as poorer disease-free and overall survival. In multivariate analysis, hyperferritinemia remained an independent poor prognosis factor. The level of ferritin at diagnosis has a major impact on relapse suggesting a link between inflammation, oxidative stress and chemoresistance in AML.

Erlotinib antagonizes ABC transporters in acute myeloid leukemia

Erlotinib was originally developed as an epidermal growth factor receptor (EGFR)-specific inhibitor for the treatment of solid malignancies, yet also exerts significant EGFR-independent antileukemic effects in vitro and in vivo. The molecular mechanisms underlying the clinical antileukemic activity of erlotinib as a standalone agent have not yet been precisely elucidated. Conversely, in preclinical settings, erlotinib has been shown to inhibit the constitutive activation of SRC kinases and mTOR, as well as to synergize with the DNA methyltransferase inhibitor azacytidine (a reference therapeutic for a subset of leukemia patients) by promoting its intracellular accumulation. Here, we show that both erlotinib and gefitinib (another EGFR inhibitor) inhibit transmembrane transporters of the ATP-binding cassette (ABC) family, including P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP), also in acute myeloid leukemia (AML) cells that do not overexpress these pumps. Thus, inhibition of drug efflux by erlotinib and gefitinib selectively exacerbated (in a synergistic or additive fashion) the cytotoxic response of KG-1 cells to chemotherapeutic agents that are normally extruded by ABC transporters (e.g., doxorubicin and etoposide). Erlotinib limited drug export via ABC transporters by multiple mechanisms, including the downregulation of surface-exposed pumps and the modulation of their ATPase activity. The effects of erlotinib on drug efflux and its chemosensitization profile persisted in patient-derived CD34+ cells, suggesting that erlotinib might be particularly efficient in antagonizing leukemic (stem cell) subpopulations, irrespective of whether they exhibit or not increased drug efflux via ABC transporters.

Improved Outcome of Acute Promyelocytic Leukemia With High WBC Counts Over the Last 15 Years: The European APL Group Experience

Purpose

Acute promyelocytic leukemia (APL) with pretreatment WBC counts greater than 10,000/μL is still considered to carry a poorer prognosis than APL with WBC lower than 10,000/mL. We evaluated outcome improvement in such patients in recent years.

Patients and Methods

Nine hundred two patients with APL, including 204 patients and 68 patients with WBC counts more than 10,000/μL and more than 50,000/μL, respectively, were enrolled between 1993 and 2005 in two successive randomized trials of the European APL group (APL 93 and APL 2000) that tested, in particular, the modalities of combination of all-trans retinoic acid (ATRA) and chemotherapy, maintenance treatment, escalating doses of cytarabine, early administration of dexamethasone, and CNS prophylaxis.

Results

Between the APL 93 and 2000 trials, the complete response (CR) rate increased from 89.6% to 93%, and the 5-year cumulative incidence of relapse (CIR) decreased from 40% to 9.5% in patients with WBC counts of 10,000 to 50,000/μL. In patients with WBC counts more than 50,000/μL, the CR rate increased from 82% to 91%, and 5-year CIR decreased from 59% to 24%. Whereas in the APL 93 trial, increased WBC counts were significantly associated with higher CIR and shorter survival, this was not the case in the APL 2000 trial. In patients with increased WBC counts, enrollment onto the APL 2000 trial (v APL 93) and combined maintenance with ATRA and chemotherapy were associated with significantly lower CIR and better survival.

Conclusion

Outcome of APL with high WBC count has markedly improved over the years as a result of fewer early deaths and fewer relapses. Better initial supportive care and combined maintenance treatment have contributed to this improvement.

Molecular determinants of immunogenic cell death: surface exposure of calreticulin makes the difference

The treatment of cancer by chemotherapy causes tumour cell death, mostly by apoptosis. This tumour cell death may or may not elicit an immune response. At least in some cases, the efficacy of chemotherapy critically depends on the induction of immunogenic cell death that is a type of cell demise that stimulates the activation of an adaptative anti-tumour immune response, which in turn helps to eradicate residual cancer (stem) cells. Indeed, anthracyclins care more efficient in curing tumours in immunocompetent than in T cell-deficient mice. The molecular mechanism implicated in this anti-tumour T cell activation was recently discovered. Anthracyclins cause immunogenic cell death due to their specific capacity to stimulate the translocation of calreticulin to the cell surface. Calreticulin then acts as an "eat me" signal for dendritic cells, allowing them to phagocytose tumour cells and to prime tumour antigen-specific cytotoxic T cells. Importantly, non-immunogenic chemotherapy can be rendered immunogenic by adsorbing recombinant calreticulin to tumour cells or by enforcing the translocation of endogenous calreticulin to the cell surface by means of PP1/GADD34 inhibitors. This strategy could have major implications for the treatment of human cancer. Indeed, in vivo treatments with anthracyclins can cause the translocation of calreticulin to the surface of circulating tumour cells, in patients with acute myeloid leukaemia (AML). The challenge will be to determine whether the exposure of calreticulin translocation on the tumour cell surface is linked to chemotherapy-induced anti-tumour immune responses and therapeutic efficacy in human cancer.

Successful outcome of disseminated Fusarium infection with skin localization treated with voriconazole and amphotericin B-lipid complex in a patient with acute leukemia

A disseminated Fusarium oxysporum infection with skin localization was diagnosed in a woman with a relapse of B-acute leukemia during induction chemotherapy. The infection was refractory to amphotericin B-lipid complex alone but responded successfully when voriconazole was added.