Akute myeloische Leukämie I

V362 Young Investigator Award: Der CD33 Einzelnukleotid-Polymorphismus rs12459419 ist ein prädiktiver Faktor bei Patienten mit NPM1-mutierter AML, die Gemtuzumab-Ozogamizin erhalten
Katrin Teich, Hannover, D

Gemtuzumab ozogamicin (GO) is a humanized anti-CD33 monoclonal antibody linked to the cytotoxic agent calicheamicin. The response of patients suffering from acute myeloid leukemia (AML) to therapy with GO is influenced by several factors. One factor might be the CD33-coding single nucleotide polymorphism (SNP) rs12459419 (NM_001772.4:c.41 C>T; Ala14Val in exon 2) as GO needs to bind to CD33. Rs12459419 affects alternative splicing of CD33 resulting in the loss of exon 2 for the T allele (rs12459419 c.41 T/T and c.41 T/T) which leads to a shorter isoform lacking the GO binding site.

The effect of the SNP was studied in the AMLSG 09-09 Phase III study. All patients were eligible for intensive therapy and had a mutation in nucleophosmin1 (NPM1) and were randomly assigned (1:1) to receive GO (n=273, GO arm) versus no GO (n=272, standard arm) in combination with 2 cycles of induction chemotherapy. 545 patients were genotyped using the TaqMan SNP Genotyping Assay rs12459419. Response to therapy and clinical outcome of patients treated with or without GO were analyzed to evaluate whether the effect of GO varies with the SNP genotype.

Hematological recovery time was not influenced by the SNP genotype. Complete remission (CR) or CR with incomplete hematologic recovery was not significantly different between the SNP genotypes. Event- free survival (EFS) showed no significant difference in the treatment effect of GO compared to the standard arm. However, patients with c.41 C/C genotype in the GO arm had a significantly improved relapse-free survival (RFS) (P=0.03) and a significantly reduced cumulative incidence of relapse (CIR) (P=0.023) compared to the standard arm. Cumulative incidence of death in remission was not significantly influenced by the SNP genotype. No significant correlation of the SNP with age or sex could be observed. A separate analysis of EFS and RFS for female patients showed a trend towards a genotype- independent benefit in female patients treated with GO whereas male patients showed a trend to better EFS and RFS only for the c.41 C/C genotype.

Our study shows a similar signal as the data from Lamba et al. with regard to an improved RFS and reduced CIR for patients with c.41 C/C genotype treated with GO and suggests that rs12459419 is one of the predictive factors that impacts the rate of relapse in patients with NPM1 mutated AML receiving GO. As testing for the SNP is technically simple, it can be easily implemented into routine diagnostics.


V468 Die orale Version des Azacitidin verlängert das Gesamt- und das rezidivfreie Überleben bei Patienten mit Akuter Myeloischer Leukämie (AML) in der 1. Remission nach Intensiver Chemotherapie (IC) mit oder ohne Konsolidierung: Ergebnisse der QUAZAR AML-001 Erhaltungstherapie-Studie

Hartmut Döhner, Ulm, D

Introduction: 40-60% of older patients (pts) with AML achieve complete remission (CR) with IC, but most will relapse despite receiving consolidation (CON) treatment (Tx). In the phase 3 randomized QUAZAR AML-001 trial, Oral-AZA significantly prolonged OS and RFS vs placebo (PBO) in pts with AML in first remission after induction ± CON. Before study entry, use of CON and number of CON cycles was at physicians' discretion, and eligibility for QUAZAR AML-001 was not contingent on CON use. We assessed OS and EFS in QUAZAR AML-001 pt subgroups defined by number of CON courses before study entry. Methods: Pts were aged ≥55 yrs with intermediate-/poor-risk cytogenetics and ECOG PS ≤3. Within 4 mo of attaining CR/CRi, pts were randomized 1:1 to Oral-AZA 300mg or PBO QD for 14d/28d Tx cycle. OS and RFS were assessed among pts who received No, 1, or ≥2 CON cycles. Induction and CON were regimens received before and after, respectively, date of first CR/CRi.

Results: 238 pts were randomized to Oral-AZA and 234 to PBO. Most pts (80%) received CON before study entry. The No CON cohort had 94 pts (20%; Oral-AZA 52, PBO 42), 1 CON had 212 pts (45%; Oral- AZA 110, PBO 102), and ≥2 CON had 166 pts (35%; Oral-AZA 76, PBO 90), including 19 pts (Oral-AZA 6, PBO 13) who received 3 CON cycles. Of 97 pts who received ≥2 induction courses, 21 (Oral-AZA 14, PBO 7) had No CON and 76 (Oral-AZA 43, PBO 33) had ≥1 CON cycle. Baseline characteristics were similar between Tx arms and cohorts. In No CON pts, median OS from randomization with Oral-AZA vs PBO was 23.3 vs 10.9 mo (HR 0.55 [95%CI 0.34, 0.89]) and median RFS was 8.4 vs 3.9 mo (0.55 [0.34, 0.88]). In 1 CON pts, median OS with Oral-AZA vs PBO was 21.0 vs 14.3 mo (HR 0.75 [95%CI 0.55, 1.02]) and median RFS was 10.0 vs 4.7 mo (0.72 [0.53, 0.99]). In ≥2 CON pts, median OS was 28.6 mo with Oral- AZA vs 17.6 mo with PBO (HR 0.75 [95%CI 0.50, 1.11]), and median RFS was 13.0 vs 6.1 mo (0.59 [0.41, 0.87]).

Conclusions: Oral-AZA improved survival vs PBO regardless of number of prior CON cycles. In the Oral- AZA arm, median OS for pts who received No CON was similar to OS of pts who received 1 CON cycle (23.3 and 21.0 mo). Results should be interpreted cautiously; CON cohorts were not prospectively defined and analyses not powered for statistical comparisons. Yet, these data suggest older pts with AML in remission after induction can benefit from Oral-AZA, regardless of their fitness to receive CON or the number of CON cycles received.


V587 Pevonedistat (P) plus Azacitidine (A) vs A Monotherapie bei Myelodysplastischen Syndromen mit hohem Risiko (HR-MDS): Ergebnisse der Wirksamkeit und Sicherheit in der Studie P-2001 (NCT02610777)
Aristoteles Giagounidis, Düsseldorf, D

Introduction: P, an investigational, first-in-class inhibitor of NEDD8-activating enzyme, disrupts degradation of select proteins, leading to cancer cell death.

Methods: Patients (pts) with HR-MDS/chronic myelomonocytic leukemia (Revised International Prognostic Scoring System risk >3, including intermediate [≥5% blasts], high or very high risk) or low- blast acute myeloid leukemia (AML) naive to hypomethylating agents were randomized 1:1 to receive P (20 mg/m2 intravenously [IV] on days 1, 3, 5) + A (75 mg/m2 IV/subcutaneously on days 1-5, 8, 9) (n=58) or A alone (n=62) in 28-day cycles until unacceptable toxicity, relapse from complete remission (CR) or partial remission (PR), transformation to AML or progression. The study was powered for event-free survival (EFS: time from randomization to death/transformation to AML, whichever occurred first). This report focuses on clinical & safety analyses, and cytogenetic & genetic characterization of pts with HR- MDS.

Results: In the intent-to-treat population (n=120), EFS trended longer (median 21.0 vs 16.6 months [mos]; hazard ratio [HR] 0.67; 95% confidence interval [CI] 0.42-1.05; p=.076) with P+A vs A. In pts with HR-MDS (n=67), baseline characteristics were balanced between arms. EFS was longer with P+A vs A (median 20.2 vs 14.8 mos; HR 0.54; 95% CI 0.29-1.00; p=.045). For pts with MDS assessed as high risk by the Cleveland Clinic model formula (n=16 per arm)—which incorporates cytogenetics, clinical & genetic parameters—median EFS was 20.2 vs 11.7 mos (HR 0.39; 95% CI 0.17-0.90; p=.023) and median overall survival (OS) was 24.2 vs 14.2 mos (HR 0.45; 95% CI 0.19-1.05; p=.056) with P+A vs A. Overall response rate in response-evaluable pts (n=59, CR+PR+hematologic improvement) was 79% with P+A vs 57% with A, with a CR rate of 52% vs 27% (p=.050); median duration of response (DR) was 34.6 vs 13.1 mos (p=.106). Median (range) time to AML transformation in pts who transformed (P+A [n=5] vs A [n=9]) was 12.2 (4.6-12.6) vs 5.9 (1.7-14.8) mos. A dose intensity was 98% (median) in both arms. Exposure-adjusted adverse event (AE) rates were lower with P+A vs A. Clinical activity of P+A was noted in pts with adverse-risk mutations.

Conclusions: In pts with HR-MDS, P+A vs A prolonged EFS, delayed transformation to AML, nearly doubled the CR rate & tripled the DR. EFS & OS favored P+A vs A in pts with high-risk MDS assessed by the formula above. Exposure-adjusted AE rates were lower with P+A vs A, without added myelosuppression.

V416 Immuntherapie der AML mit einem bispezifischen T-Zell-Antikörper gerichtet gegen das intrazelluläre Targetantigen WT1
Gerulf Hänel, München, D

Introduction: Antibody-based immunotherapy relies mostly on cell surface antigens, whereas targeting of intracellular antigens remains challenging. Targeting intracellular antigens enlarges the number of suitable tumor-associated target antigens with a more restricted expression profile, such as Wilms tumor 1 (WT1) frequently overexpressed in acute myeloid leukemia (AML). Here we evaluate a 2+1 T Cell Bispecific (TCB) antibody targeting WT1 by bivalent recognition of the peptide RMFPNAPYL presented on human leucocyte antigen allele A*02 (HLA-A2).


Methods: WT1-TCB-mediated killing against cell lines and primary AML cells was evaluated in short- term killing experiments. Specific lysis of AML blasts was additionally assessed using our established feeder layer-based ex vivo long-term culture system. For in vivo testing, humanized NSG mice were engrafted subcutaneously with WT1-expressing HLA-A2+ SKM-1 tumor cells followed by weekly WT1-TCB administration.

Results: WT1-TCB elicited antibody-mediated T-cell killing against peptide-pulsed T2 cells and AML cell lines in a WT1 and HLA-restricted manner. In short-term killing experiments WT1-TCB mediated killing of primary AML cells in allogenic and autologous settings at comparable efficacies (mean specific lysis ±SEM: 76.6±5.9% and 64.7±12.4%; n=7 and 3, respectively). Lysis was dose-dependent (EC50=0.1 μg/mL) and accompanied by secretion of IFN-γ and Granzyme B reflecting lysis efficacies.

WT1-TCBs further mediated specific lysis of primary AML cells in long-term cultures with allogenic healthy donor T cells (mean specific lysis ±SEM: 67±6% after 13-14 days; n=18). Correspondingly, up- regulation of T cell activation and exhaustion markers was observed (MFI fold change ±SEM: CD69: 9.3±1.5, PD-1: 5.1±0.7, TIM-3: 4.7±0.6; n=22). WT1-TCBs also mediated killing of primary AML cells in an autologous setting (mean specific lysis ±SEM: 38±13% after 13-14 days; n=5). Furthermore, WT1-TCB-treated humanized mice bearing SKM-1 tumors showed a dose dependent and significant reduction in tumor growth resulting in tumor control.

Conclusion: In summary, we show that WT1-TCB facilitates potent in vitro, ex vivo and in vivo killing of AML cell lines and primary AML cells and accordingly, a multicenter, phase I first-in-human clinical trial (NCT04580121) has been initiated for the treatment of relapsed/refractory AML. As a participating site, we will utilize our preclinical analysis as companion diagnostics within the clinical trial.


V401 Identifizierung von Resistenzmechanismen gegen eine Venetoclax/Azacytidin-Kombinationsbehandlung in der akuten myeloischen Leukämie mittels eines genomweiten CRISPR/Cas9-screens
Katharina Weidenauer, Heidelberg, D

Introduction: Venetoclax-Azacytidine combination treatment is a novel therapeutic approach for elderly AML patients who are unfit for intensive induction chemotherapy. Upfront resistance as well as relapse remain major challenges. AML with Venetoclax-Azacytidine resistance does not respond to any known therapy and carries a dismal prognosis. Overcoming Venetoclax-Azacytidine resistance remains an important unmet clinical need.

Methods: We performed a genome-wide CRISPR/Cas9-libraryscreen to identify genes that induce or overcome Venetoclax-Azacytidine resistance. Two different cell lines (HL60, OCIAML2) were transduced with the Toronto-library (TKOv3) targeting 18,053 protein coding genes. Cell were exposed to Venetoclax- Azacytidine combination at IC70 concentrations. DNA was isolated on day 14. The gRNAs that were enriched or depleted were identified by Illumina Sequencing.

Results: The highest positively ranked genes were PAMIP1 and BAX, both regulators of apoptosis induction and therefore, important mediators of therapy resistance. These findings indicated the validity of the screening approach. Overall, 39 genes were identified to be significantly associated with conferring resistance. Depletion of 1,242 genes was associated with overcoming therapy resistance. The top negatively ranked genes were consistently associated with key biological processes and signaling pathways that restored cellular sensitivity to treatment upon knockout. Of note, the Venetoclax- Azacytidine modulating genes showed only weak overlap with published Venetoclax monotherapy resistance screen results. The most promising candidate genes for overcoming Venetoclax-Azacytidine resistance were involved in maintenance of the mitochondrial membrane potential, MAPK signaling and transcriptional regulation.

Conclusion: This genome-wide screening approach identified several pathways and multiple genes that conferred resistance to Venetoclax/Azacytidine treatment as well as sensitizer genes, whose inhibition could be promising targets for future combination therapies. By validating our top-hits, we may identify and implement novel Venetoclax-based treatment strategies overcoming resistance.