PURPOSE: Sixty percent of newly diagnosed patients with acute myeloid leukemia (ND-AML) receiving frontline therapy attain a complete response (CR), yet 30%-40% of patients relapse. Relapsed or refractory AML (R/R-AML) remains a particularly adverse population necessitating improved therapeutic options. This phase Ib/II study evaluated the safety and efficacy of fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin combined with the B-cell lymphoma-2 inhibitor venetoclax in ND-AML and R/R-AML. MATERIALS AND METHODS: The phase IB portion (PIB) enrolled patients with R/R-AML using a 3 + 3 dose escalation and de-escalation algorithm for identification of maximum tolerated dose and dose-limiting toxicities. The phase II portion enrolled patients into two arms to evaluate response and time-to-event end points: phase IIA (PIIA): ND-AML and phase IIB (PIIB): R/R-AML. RESULTS: Sixty-eight patients have enrolled to date (PIB, 16; PIIA, 29; PIIB, 23). Median age was 46 years (range, 20-73). Grade 3 and 4 adverse events occurring in ≥ 10% of patients included febrile neutropenia (50%), bacteremia (35%), pneumonia (28%), and sepsis (12%). The overall response rate for PIB, PIIA, and PIIB was 75%, 97%, and 70% with 75%, 90%, and 61%, respectively, achieving a composite CR. Measurable residual disease–negative composite CR was attained in 96% of ND-AML and 69% of R/R-AML patients. After a median follow-up of 12 months, median overall survival (OS) for both PII cohorts was not reached. Fifty-six percent of patients proceeded to allogeneic hematopoietic stem-cell transplantation (ND-AML, 69%; R/R-AML, 46%). In R/R-AML, allogeneic hematopoietic stem-cell transplantation resulted in a significant improvement in OS (median OS, NR; 1-year OS, 87%). One-year survival post-HSCT was 94% in ND-AML and 78% in R/R-AML. CONCLUSION: Fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin + venetoclax represents an effective intensive treatment regimen in ND-AML and R/R-AML patients, associated with deep remissions and a high rate of transition to successful transplantation.

Because protein function regulates the phenotypic characteristics of cancer, a functional proteomic classification system could provide important information for pathogenesis and prognosis. With the goal of ultimately developing a proteomic-based classification of acute myeloid leukemia (AML), we assayed leukemia-enriched cells from 256 newly diagnosed AML patients, for 51 total and phosphoproteins from apoptosis, cell-cycle, and signal-transduction pathways, using reverse-phase protein arrays. Expression in matched blood and marrow samples were similar for 44 proteins; another 7 had small fold changes (8%-55%), suggesting that functional proteomics of leukemia-enriched cells in the marrow and periphery are similar. Protein expression patterns were independent of clinical characteristics. However, 24 proteins were significantly different between French-American-British subtypes, defining distinct signatures for each. Expression signatures for AML with cytogenetic abnormalities involving −5 or −7 were similar suggesting mechanistic commonalities. Distinct expression patterns for FMS-like tyrosine kinase 3–internal tandem duplication were also identified. Principal component analysis defined 7 protein signature groups, with prognostic information distinct from cytogenetics that correlated with remission attainment, relapse, and overall survival. In conclusion, protein expression profiling patterns in AML correlate with known morphologic features, cytogenetics, and outcome. Confirmation in independent studies may also provide pathophysiologic insights facilitating triage of patients to emerging targeted therapies.

The role of circulating cytokines and chemokines (C&Ckine) in activating signal transduction in leukemic cells is incompletely defined. We hypothesized that comprehensive profiling of C&Ckine expression in leukemia would provide greater insight compared with individual analyses. We used multiplex array technology to simultaneously measure the level of 27 C&Ckines in serum from 176 acute myelogenous leukemia (AML) and 114 myelodysplastic syndrome (MDS) patients and 19 normal controls. C&Ckine levels in AML and MDS differed significantly from normal controls (5 higher, 13 lower) but were similar to each other for 24 of 27 analytes, with interleukin-8 and interleukin-13 higher in AML and vascular endothelial growth factor A higher in MDS. Levels did not correlate with age, gender, infection, or blood counts; however, 3 correlated with specific cytognetic abnormalities in AML. Individually, few cytokines had any correlation with response or survival. In newly diagnosed AML, 8 C&Ckine signatures, distinct from the normal control signature, were observed. These signatures had prognostic impact, affecting remission, primary resistance, relapse rates, and overall survival, individually (P = .003) and in multivariable analysis (P = .004). These patterns suggest specific therapeutic interventions to investigate in subsets of AML patients. In conclusion, C&Ckine expression in AML and MDS differs from normal, is similar with one another, and forms recurrent patterns of expression with prognostic relevance.

In contrast to the curative effect of allogenic stem cell transplantation in acute myeloid leukemia via T cell activity, only modest responses are achieved with checkpoint-blockade therapy, which might be explained by T cell phenotypes and T cell receptor (TCR) repertoires. Here, we show by paired single-cell RNA analysis and TCR repertoire profiling of bone marrow cells in relapsed/refractory acute myeloid leukemia patients pre/post azacytidine+nivolumab treatment that the disease-related T cell subsets are highly heterogeneous, and their abundance changes following PD-1 blockade-based treatment. TCR repertoires expand and primarily emerge from CD8⁺ cells in patients responding to treatment or having a stable disease, while TCR repertoires contract in therapy^-resistant patients. Trajectory analysis reveals a continuum of CD8⁺ T cell phenotypes, characterized by differential expression of granzyme B and a bone marrow-residing memory CD8⁺ T cell subset, in which a population with stem-like properties expressing granzyme K is enriched in responders. Chromosome 7/7q loss, on the other hand, is a cancer-intrinsic genomic marker of PD-1 blockade resistance in AML. In summary, our study reveals that adaptive T cell plasticity and genomic alterations determine responses to PD-1 blockade in acute myeloid leukemia.

Autophagy is a cellular adaptive mechanism to stress, including that induced by chemotherapeutic agents. Reverse phase protein array suggested that high expression of the essential autophagy-related protein, Atg7, was associated with shorter remission in newly diagnosed acute myeloid leukemia (AML) patient samples, indicating a role in chemoresistance. Knockdown of Atg7 in AML cells using short hairpin RNA markedly increased apoptosis and DNA damage following treatment with cytarabine and idarubicin. Interestingly, coculture of AML cells with stromal cells increased autophagy and chemoresistance in the AML cells exposed to chemotherapeutic agents, and this was reversed following Atg7 knockdown. This effect was further enhanced by concomitant knockdown of Atg7 in both AML and stromal cells. These findings strongly suggest that Atg7, and likely microenvironment autophagy in general, plays an important role in AML chemoresistance. Mechanistic studies revealed that Atg7 knockdown induced a proapoptotic phenotype in AML cells, which was manifested by an increased NOXA expression at the transcriptional level. Finally, in a mouse model of human leukemia, Atg7 knockdown extended overall survival after chemotherapy. Thus, the inhibition of Atg7 appears to be a valid strategy to enhance chemosensitivity, and it could indeed improve outcomes in AML therapy. Publisher9s Note: There is an Inside Blood Commentary on this article in this issue. Key Points Atg7 expression is associated with shorter remission duration in AML. Atg7 inhibition is a proapoptotic phenotype and enhances sensitivity to chemotherapy.