Acute myeloid leukemia (AML) in older unfit patients is a therapeutic challenge for clinical hematologists. We evaluated the efficacy and safety of a novel low-intensity regimen consisting of low-dose cytarabine and cladribine (LD-AC+cladribine) in first-line treatment of elderly (≥60 years) AML patients not eligible for intensive chemotherapy (IC) who had either the Eastern Cooperative Oncology Group performance status (ECOG PS) ≥2 or the hematopoietic cell transplantation comorbidity index (HCT-CI) score ≥3. The induction phase included two cycles of LD-AC+cladribine. Patients who achieved at least partial remission (PR) received maintenance treatment with LD-AC alone. Overall, 117 patients with a median age of 70 years were enrolled. Adverse cytogenetics, ECOG PS ≥2 and HCT-CI score ≥3 was observed in 43.5%, 60%, and 58% of patients, respectively. The response rate (≥PR) was 54% (complete remission [CR], 32%; CR with incomplete hematologic recovery [CRi], 5%). A median overall survival (OS) was 21 and 8.8 months in CR/CRi and PR group, respectively. Advanced age (≥75 years) and adverse cytogenetics had a negative impact on OS. The 56-day mortality rate was 20.5%. In conclusion, LD-AC+cladribine is a beneficial therapeutic option with a predictable safety profile in elderly AML patients not eligible for IC.

The development of novel drugs with different mechanisms of action has dramatically changed the treatment landscape of AML patients in recent years. Considering a significant dysregulation of the immune system, inhibitors of immune checkpoint (ICI) proteins provide a substantial therapeutic option for those subjects. However, use of ICI in haematological malignancies remains very limited, in contrast to their wide use in solid tumours. Here, we analysed expression patterns of the most promising selected checkpoint-based therapeutic targets in AML patients. Peripheral blood of 72 untreated AML patients was used for flow cytometric analysis. Expression of PD-1, PD-L1, CTLA-4, and B7-H3 was assessed within CD4+ (Th) lymphocytes and CD33+ blast cells. Patients were stratified based on therapy outcome and cytogenetic molecular risk. AML non-responders (NR) showed a higher frequency of PD-1 in Th cells compared to those with complete remission (CR). Reduced blast cell level of CTLA-4 was another factor differentiating CR from NR subjects. Elevated levels of PD-1 were associated with a trend for poorer patients’ survival. Additionally, prognosis for AML patients was worse in case of a higher frequency of B7-H3 in Th lymphocytes. In summary, we showed the significance of selected ICI as outcome predictors in AML management. Further, multicentre studies are required for validation of those data.

Background: Chronic lymphocytic leukemia (CLL) is characterized by malignant B lymphocyte accumulation and progressive immune dysfunction. The immune checkpoint molecule TIM-3 and its ligand galectin-9 (Gal-9) contribute to T cell exhaustion, impairing anti-tumour immunity. Interleukin-27 (IL-27) has pleiotropic immunomodulatory properties, but its impact on TIM-3 and Gal-9 expression in CLL remains unclear. Methods: Peripheral blood mononuclear cells (PBMCs) from 20 treatment-naive CLL patients were cultured with or without IL-27 (100 ng/mL) for 72 h. Flow cytometry assessed TIM-3 and Gal-9 expression on CD4⁺, CD8⁺, and CD19⁺ cells. Results: IL-27 stimulation significantly increased TIM-3 expression on CD8⁺ T cells (2.18 ± 0.32% vs. 3.09 ± 0.49%, p = 0.009), a hallmark of T cell exhaustion. IL-27 also modestly increased intracellular Gal-9 levels in total lymphocytes (93.91 ± 1.17% vs. 96.55 ± 0.67%, p = 0.005). Additionally, IL-27 reduced CD4⁺ T cell proportions (26.71 ± 4.19% vs. 22.01 ± 3.23%, p = 0.010). Although numerically modest, these changes may be biologically pertinent in the context of checkpoint-mediated CD8⁺ T-cell exhaustion. Conclusions: IL-27 may enhance immunosuppressive mechanisms in CLL by modulating immune checkpoint expression, potentially contributing to disease progression. These ex vivo findings in PBMCs from CLL patients indicate the IL-27-associated modulation of checkpoint expression under the conditions tested. In the absence of parallel healthy-donor controls, CLL specificity cannot be established in this study.

Background: Measurable residual disease (MRD) is an important biomarker in acute myeloid leukemia (AML). Among patients who achieve remission after standard chemotherapy, detection of MRD (MRD+) after two cycles of intensive chemotherapy, at the end of consolidation and before allogeneic stem cell transplantation (alloHSCT) is a strong prognostic factor for relapse and shorter overall survival (OS) (Short NJ, JAMA Oncol. 2020). The optimal time-points to asses MRD, and MRD cut-offs as well as whether eliminating of MRD due to further chemotherapy improves an outcome still remain open questions. PALG-AML1/2016 study aims to compare the safety and efficacy of two commonly used induction and salvage regimens in AML (NCT03257241). This is also the first international randomized trial in AML induction to prospectively evaluate the impact of MRD on overall survival, using multi-modality testing (flow-cytometry, FC; next-generation sequencing, NGS) of serial samples. Study Design: In this study, 582 adult patients with newly-diagnosed AML will be randomized to DA-90 or DAC induction. Patients with complete remission (CR) or CR with incomplete hematologic recovery (CRi) receive further post-remission therapy adjusted to predefined risk group. The serial samples for multimodal MRD evaluation are collected at D14 (MRD-1), at time of CR/CRi after single or two induction cycles (MRD-2), and after each consolidation cycle (MRD-3, -4, -5). Material and Methods. The aim of this preliminary analysis was to evaluate the prognostic value of bone marrow assessment at D14 both cytological and by FC (MRD-1) as well as the kinetics of MRD during post-remission treatment. Multivariable logistic regression models were developed with significant variables from univariate analyses, including MRD and blast count. The predictive power of the MRD level and blasts percentage at D14 was evaluated by receiver operating characteristics (ROC) and area under the curve (AUC) analysis to determine the ability of the biomarkers to accurately predict response to the induction treatment. Results: The study group consisted of 284 patients (mean age: 47.1 ± 10.9) recruited until the end of May 2021. MRD-1 by FC was reported in 225 patients. CR and CRi either after single or double induction were achieved in 175 (61.6%) and 48 (16.9%) patients, respectively leading to an overall CR/CRi rate 78.5%. In univariate analyses, the factors significantly associated with achieving CR/CRi were: ELN high-risk group (OR 0.12, 95% CI: 0.05-0.33, p<0.0001), percentage of blasts at D14 (OR 0.95, 95% CI: 0.93-0.97, p<0.0001) and MRD-1 level (OR 0.94, 95% CI: 0.92-0.96, p<0.0001). A ROC analysis showed that AUC for the blasts count (0.71, 95%CI: 0.61-0.80) was significantly lower (p=0.0028) than AUC for MRD-1 levels 0.81 (95%CI: 0.74-0.89). Furthermore, two multivariate models, including ELN high-risk group and blasts or MRD biomarker, were evaluated. The model with blast percentage had an AUC of 0.83 (95% CI: 0.76-0.91). The model with MRD-1 level yielded higher AUC (p=0.0039) of 0.90 (95% CI: 0.84-0.95) and had a lower Akaike information criterion (116.9 vs. 127.1), indicating a better-fit model. In the analyzed group MRD-2 <0.1% did not have a predictive value for OS. MRD-3 at the end of consolidation 1 was reported in 182 patients: MRD+ in 99 (54.4%) and MRD- in 83 (45.6%) patients. Results of MRD-4 at the end of consolidation 2 were available in 114 patients with 49 (43.0%) being MRD+ and 65 (57.0%) MRD-. Fifty-eight patients (35 MRD-2+ and 23 MRD-2-) were evaluated for MRD kinetics from the end of induction until the end of consolidation 3. Conversion rate from MRD- to MRD+ was 13% (n=3) and from MRD+ to MRD- 34%(n=12), respectively (p=0.038). Conclusions: Our preliminary results suggest that flow cytometric bone marrow assessment on D14 has a predictive value for CR/CRi achievement and a potential prognostic utility for overall survival. The kinetics of MRD during consolidation requires further studies to better evaluate its prognostic significance. References Short NJ, JAMA Oncol. 2020; Zhou S, Fu C, et al. Association of Measurable Residual Disease with Survival Outcomes in Patients with Acute Myeloid Leukemia: A Systematic Review and Meta-analysis. 6(12):1890-1899. Disclosures: Wierzbowska: Celgene/BMS: Consultancy; Jazz: Research Funding; Novartis: Consultancy; Abbvie: Consultancy; Astellas: Consultancy; Janssen: Consultancy. Libura: Novartis: Consultancy, Research Funding. Giebel: Pfizer: Consultancy, Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau. Czemerska: Novartis: Honoraria; Takeda: Honoraria. Sobas: Novartis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Wróbel: Takeda: Honoraria, Speakers Bureau; BMS: Honoraria; Novartis: Honoraria, Speakers Bureau; BeiGene: Honoraria; Janssen: Honoraria, Speakers Bureau; Roche: Honoraria, Research Funding, Speakers Bureau. Patkowska: Bristol-Myers Squibb: Other: Travel fees; Angelini Pharma: Honoraria, Other: Travel fees; Jazz Pharmaceuticals: Other: Travel fees; Pfizer: Other: Travel fees; Astellas Pharma, Inc.: Consultancy, Other: Travel fees; Servier: Honoraria, Other: Travel fees; KCR US, Inc.: Consultancy; Novartis: Honoraria, Other: Travel fees; AMGEN: Honoraria. Desai: Kura Oncology: Consultancy; Astex: Research Funding; Agios: Consultancy; Takeda: Consultancy; Bristol Myers Squibb: Consultancy; Janssen R&D: Research Funding. Lee: Innate: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pin Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees. Ritchie: Astellas: Consultancy, Research...