Frontline Hypomethylating Agents Research Articles

Immunophenotypic Markers CD7 and CD56 Improve Risk Stratification of Frontline Hypomethylating Agents + Venetoclax in Newly Diagnosed AML

Immunophenotypic Markers CD7 and CD56 Improve Risk Stratification of Frontline Hypomethylating Agents + Venetoclax in Newly Diagnosed AML

Validation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Who Were Treated with Hypomethylating Agents (HMA)

TK and JPB Co-first; RK and AMZ are Co-senior authors. Introduction Recognition of the growing importance of genetic mutations in prognostication for pts with MDS prompted the development of IPSS-M to improve outcome prediction. Subsequent validation studies included a heterogenous groups of pts; treated & untreated pts with lower & higher risk (HR) disease, and thus the value of IPSS-M in predicting outcomes of pts with HR-MDS treated with HMA remains unclear. We aimed to evaluate the ability of IPSS-M to predict outcomes of pts with HR-MDS who were treated with HMA in a large multicenter cohort. Methods Using the multi-center VALIDATE database, we included pts with HR-MDS (Defined as IPSS score >1 or IPSS-R score > 3.5) who were treated with any HMA in the frontline setting and had available molecular data before HMA initiation. Time-to-event analysis used Kaplan-Meier estimator and the log-rank tests. Survival was measured from time of HMA initiation. We compared the different scoring systems by Harrell's c-index. Best response to HMA was assessed using the IWG 2023 response criteria in HR pts (n=480) who had a marrow evaluation within 180 days of HMA initiation. This study was supported by an independent research grant from AbbVie. Results A total of 925 pts were included in the analysis. Median age was 68 years (IQR: 62-75) and 66% of the pts were men. MDS excess blast 1/2 accounted for 65% of the diagnosis. Overall, 76% of pts were treated with HMA monotherapy (29% decitabine and 71% azacitidine), 24% received HMA combination therapy, and 39% of pts had HSCT. The most common mutations (MT) were TP53 (32%), ASXL1 (20%), TET2 (13%) and SRSF2 (12%); 36% of pts had MDS harboring >1 gene MT. As anticipated, the cohort was enriched with high risk (26%) and very high risk (46%) IPSS-R groups. According to pre-therapy IPSS-M, pts were classified into very low (2%), low (9%), moderate low (11%), moderate high (14%), high (29%) and very high (36%) risk groups. IPSS-M reclassified 54% of pts, of whom 184 (37%) were up-staged and 317 (63%) were down-staged. Specifically, 38%/21% of pts with intermediate risk IPSS-R MDS, and 30%/36% of pts with high risk IPSS-R MDS were up-staged/down-staged, respectively. In addition, 44% of pts with very high risk IPSS-R MDS were down-staged. The median follow-up time was 19 (IQR:10-35) months (mo). Median overall survival (OS) was 19 (95% CI: 17-22) mo. Overall, 35% of the pts progressed to AML during follow up. IPSS-M groups showed significant differences for both OS and LFS (p-value: <0.0001 for both). The median OS (mo, 95%CI) based on IPSS-M categories were: low (37, 25-62), moderate low (30, 23-47), moderate high (29, 22-35), high (17, 14-20), and very high (14, 12-15) (Panel A). The 3-year LFS (%) were: low (20%), moderate low (48%), moderate high (41), high (50%), and very high (59%). IPSS-M was significantly associated with OS in a multivariable model adjusted for age, sex, type of HMA, number of HMA cycles and receiving allogeneic HSCT (HR: 1.4, 95% CI:1.2-1.5). However, IPSS-M showed comparable performance when compared with the IPSS-R with c-index (95%CI): 0.599 (0.557-0.622) vs. 0.619 (0.560-0.641) for OS. In addition, IPSS-M showed similar performance for LFS: 0.583 (0.560-0.606) vs. 0.588 (0.565-0.610) (Panel B). When IPSS-M/IPSS-R were used as continuous scores, the c-indices (95%CI) for OS and LFS were: 0.617 (0.592-0.640) vs. 0.6400 (0.616-0.664) for OS and 0.598 (0.575-0.622) vs. 0.606 (0.581-0.632) for LFS. We then analyzed the performance of IPSS-R/IPSS-M in pts with HR MDS (IPSS ≥1.5). Both IPSS-R and IPSS-M had comparable performance for OS prediction (c-index:0.548 vs. 0.566) and LFS (0.551 vs. 0.538). Based on the proposed IWG 2023 response criteria, complete remission rate (CR)/ overall response rate (ORR) were 12/47%, 9/58%, 13/47%, and 17/57% of pts assigned to moderate low, moderate high, high, and very high IPSS-M risk groups. No significant association was observed between IPSS-M and ORR (OR: 1.1, p=0.475) or CR (1.1, p=0.286). Conclusions In our multi-center large cohort of pts with HR MDS treated with frontline HMA, IPSS-M significantly stratified pts for OS and LFS. However, when compared with IPSS-R, IPSS-M did not seem to substantially improve prediction of outcomes among HMA-treated pts. Our results emphasize the high predictive prognostic power of clinical features and cytogenetic alterations among HR-MDS pts treated with HMA.

Clinical Implications of TP53 Mutations/Allelic State in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Treated with Hypomethylating Agents (HMA)- a Multicenter, Retrospective Analysis from the Validate Database

TK and JPB Co-first; RK, DS, and AMZ are Co-senior authors. Introduction MDS with TP53 mutations ( TP53 MT) are associated with high-risk disease features and rapid progression to AML. Effective treatment for this aggressive subtype is still not available. As compared to monoallelic TP53 MT, biallelic MT have been associated with adverse outcomes and worse overall survival (OS), but the impact of allelic status on treatment response and OS after HMA therapy are not well established. In this study, we analyzed TP53 allelic state for a large well annotated cohort of pts with MDS who were treated with HMAs. Methods The VALIDATE database includes pts with MDS treated with frontline HMA from 14 specialized centers. Pts were considered to have biallelic TP53 MT according to the ICC definition (Arber et al. 2022, Blood) if they meet any of the following: a. two TP53 MT (variant allelic frequency [VAF]>10% for each) b. single TP53 MT with copy neutral loss of heterozygosity (CN-LOH, available for 308 pts) c. TP53 MT with del17p and d. Single TP53 MT with VAF >50%. Time to event analyses were estimated using Kaplan-Meier estimator and groups were compared by the log-rank test from the time of HMA initiation. Only higher risk (HR)-MDS pts (IPSS>1 or IPSS-R>3.5) with BM biopsy within 180 days after HMA initiation were assessed for complete response (CR) and overall response rate (ORR) according to the IWG 2023 criteria (Zeidan et al, Blood 2023) (n=480). OS was calculated from time of HMA therapy initiation. This study was supported by an independent research grant from AbbVie. Results A total of 816 pts met eligibility and were included in this analysis. Median age was 68 years (IQR: 61-74) and 64% were men. MDS excess blast (EB) 1/2 was the most common MDS subtype (62%). Overall, 78% of the pts were treated with HMA monotherapy (26% decitabine [DEC] and 74% azacitidine [AZA]) and 22% received HMA as part of combination therapy. In total, 40% of the pts underwent allogenic HSCT. Median HMA treatment time was 5 months (mo), IQR:3-11. Median follow up time was 17 mo (IQR:9-31). TP53 MT were detected in 253 pts (31%) at time of MDS diagnosis, of whom 153 (60%) pts had biallelic TP53 MT and 100 (40%) pts had monoallelic TP53 MT. Missense MTs were identified in 80% of pts with monoallelic TP53 MT. TP53 MT/del17p (33%), TP53 MT/CN-LOH (28%), and multiple TP53 MT (25%) were the most common combinations in pts with biallelic TP53 MT. Pts with TP53 MT had higher rates of MDS-EB (74% vs. 61%, p<0.001). Complex karyotype was observed in 112 (73%) pts with biallelic TP53 MT and 81 (81%) pts with monoallelic TP53 MT (p=0.154). Median number of HMA cycles among pts with TP53 MT was 8 (IQR:5-12) and higher compared to pts without TP53 MT (5 cycles, IQR:3-9), p=0.032 ( Panel-A). In a logistic regression model for CR, TP53 MT was not associated with probability of achieving CR (1.4, 0.89-2.29). CR rates for pts with biallelic TP53 MT (18%) and monoallelic TP53 MT (14%) were not significantly different, p=0.37. There were also no significant differences in ORR observed between biallelic TP53 MT (59%) and monoallelic TP53 MT (54%) pts, p=0.39. Among TP53 MTpts treated with HMA monotherapy, pts treated with AZA compared to DEC had similar odds for ORR (OR:1.1, 95%CI: 0.7-1.6)/CR (OR: 0.8, 95%CI: 0.4-1.3) and hazard for OS (HR: 1.1, 0.9-1.4). As expected, the median OS (mo, 95%CI) for pts with TP53 MT (12, 10-13) was significantly lower than pts without TP53 MT (28, 25-31), p<0.001. Importantly, pts with biallelic TP53 MT (11, 9-14) had no significant difference in median OS compared to monoallelic TP53 MT (13, 11-17), p=0.268 (Panel-B). In a multivariable cox proportional hazard regression model for OS (hazards ratio, 95%CI) adjusted for age (1.0, 0.9-1.0), HSCT (0.4, 0.3-0.4), IPSS-M score (1.2, 1.1-1.3), and complex karyotype (1.4, 1.1-1.8), TP53 MT status (1.8, 1.4-2.3) was still associated with OS. However, biallelic TP53 MT had comparable risk to monoallelic TP53 MT (1.2, 0.9-1.7). Conclusions To our knowledge, VALIDATE is the largest database of MDS pts with TP53 MT who were treated with HMA. We confirm that TP53 MT have significant negative impact on survival, but not on response to HMA therapy. Importantly, we did not observe OS differences between monoallelic and biallelic TP53 MT. We also show that the type of HMA monotherapy used does not impact outcome of these pts. Overall, pts with TP53 MT have very poor outcomes and are in desperate need of new, effective therapies.

Clinicopathologic Predictors of Hypomethylating Agent Failure in Patients with Myelodysplastic Syndromes

Background: Hypomethylating agents (HMA), such as decitabine, azacitidine, and oral decitabine/cedazuridine, are standard-of-care therapies for patients with myelodysplastic syndromes (MDS). Though they improve peripheral blood cytopenia and delay disease progression, most patients eventually lose response to these agents, a phenomenon known as HMA failure (HMA-F). Survival outcomes are poor with no Federal Drug Administration-approved treatment options in the HMA-F setting. Here, we assess MDS patients treated with HMA for potential clinical and pathological predictors of HMA-F. Methods: We retrospectively evaluated all untreated patients with MDS seen at a single tertiary cancer center between July 2017 and July 2021 and identified those who received HMA therapy after diagnosis. Baseline patient characteristics and bone marrow (BM) data, including morphology, cytogenetics, and mutations, were collected. Genomic DNA was extracted from whole BM aspirate samples and subject to 81-gene target PCR-based sequencing using a next-generation sequencing platform. Survival data was updated in July 2023. Results: A total of 799 untreated MDS patients were identified, and 455 patients (57%) eventually underwent treatment with HMA. With a median follow-up time of 46.8 months (95% confidence interval (CI): 44.4, 52.4), 174 patients (38%) were refractory to or later progressed on HMA therapy. Figure 1 depicts the differences in baseline clinical characteristics in those who remained on HMA therapy and those who developed HMA-F. HMA-treated patients who eventually developed HMA-F were more likely to be older (p=0.003), have higher BM blasts (p=0.044), and higher-risk by both IPSS-R (p=0.003) and IPSS-M (p<0.001) scoring systems. No differences were observed by HMA treatment type, number of cycles, and response. More patients underwent allogeneic stem cell transplantation while on frontline HMA therapy than after development of HMA-F (p<0.001). Figure 2 shows the distribution of mutations detected in at least 10 patients between individuals who remained on HMA therapy and those who developed HMA-F. TP53 mutations tended to be more prevalent in those who developed HMA-F (p=0.067). No mutations were detected in 31 patients (11%) on HMA therapy and 13 patients (8%) with HMA-F (p=0.222). Interestingly, patients who remained on HMA therapy more frequently had multiple mutations in the same gene than those who developed HMA-F (58 patients (21%) vs 12 patients (7%), p<0.001). The median overall survival from MDS diagnosis was 35.9 months (95% CI: 31.9, 55.3) in those who remained on HMA therapy vs 22.5 months (95% CI: 18.9, 25.7) in those who developed HMA-F (p<0.001). When only accounting for patients who underwent SCT, there was no difference in survival between the two groups (current HMA therapy 53.9 months vs HMA-F 58.1 months, p=0.541). In the HMA-F cohort, the median overall survival from the time of HMA-F was 6.8 months (95% CI: 5.5, 9.6). Conclusions: In this group of MDS patients treated with HMA, patients who eventually developed HMA-F were older with higher BM blasts and higher-risk disease by IPSS-R and IPSS-M. No statistically significant differences were observed by HMA therapy details, cytogenetics, and specific mutations, but those with multiple mutations in the same gene tended to remain on HMA therapy. Further investigation into predictors of HMA-F and potential other treatment modalities is warranted.

Validation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Who Underwent Allogenic Stem Cell Transplantation (HSCT)

TK and JPB Co-first; RK and AMZ are Co-senior authors. Introduction MDS are genetically heterogenous neoplasms with diverse prognoses. While hypomethylating agents (HMA) can improve outcomes, HSCT remains the only potentially curative therapy. The IPSS-M incorporates clinical and molecular features to improve outcome prediction beyond traditional risk stratification tools. The IPSS-M has been validated in studies that either variably included pts who underwent HSCT, were limited by sample size, or were single-institution analyses. We aimed to validate the performance of the IPSS-M in predicting outcomes among pts with MDS who were treated with HMAs and subsequently underwent HSCT. Methods The VALIDATE database includes MDS pts treated with frontline HMA from 14 specialized centers. Only pts with available molecular data pre-HMA therapy and subsequently underwent HSCT were included. Time-to-event analyses used Kaplan-Meier estimator and the log-rank test. Overall survival (OS) was measured from time of HSCT. Multivariate-adjusted survival analysis used Cox proportional hazards. We compared the different scoring scores by Harrell's c-index. This study was supported by an independent research grant from AbbVie. Results A total of 350 pts met eligibility ( Panel A). Median age was 63 years (IQR: 58-68). MDS with excess blasts 1/2 (66%) was the most common type. Overall, 74% of pts received HMA monotherapy (27% decitabine; 73% azacitidine), while 26% received HMA in a combined therapy. The most prevalent mutations were TP53 (29%), ASXL1 (21%), RUNX1 (13%), STAG2 (12%), SRSF2 (12%), and DNMT3A (11%); 53% of pts had disease harboring >1 gene mutation. Only 44% had TP53 CN-LOH and 40% had MLL-PTD testing. The most common donor types were matched unrelated donors (MUD, 46%), haploidentical donors (21%), and matched related donors (MRD, 17%). Myeloablative, non-myeloablative, and reduced-intensity conditioning were used in 38%, 27%, and 27% of the pts, respectively. Only 14% of pts received post-HSCT maintenance therapy. Our cohort was enriched with very high risk (41%) and high risk (30%) IPSS-R groups at time of diagnosis, while very low (1%), low (9%), and intermediate (20%) IPSS-R risk groups accounted for remaining 29% of pts. According to the IPSS-M, pts were classified into very low (2%), low (10%), moderate low (13%), moderate high (14%), high (27%) and very high (34%) risk groups. The IPSS-M re-stratified 198 (57%) pts, of whom 77 (39%) pts were up-staged and 121 (61%) pts were down-staged. More specifically, 35% and 26% of pts with intermediate risk IPSS-R MDS, and 32% and 35% of pts with high risk IPSS-R MDS were up-staged and down-staged, respectively. Importantly, 45% of pts with very high risk IPSS-R MDS were down-staged. Median follow-up time was 20 (IQR:8-36) months (mo). The median OS for the entire cohort was 32 mo (IQR:10-Not reached [NR]). The IPSS-M groups showed significantly different OS (p-value= 0.001, Panel B)withmedian OS (mo, 95%CI) of: very low (NR, 11.5-NR), low (55, 22-NR), moderate low (48, 25-NR), moderate high (35, 22-NR), high (29, 23-NR), and very high (20, 13-28). The 5-year OS (%) were as following: very low (56%), low (47%), moderate low (37%), moderate high (40), high (43%), and very high (17%). IPSS-M risk (HR: 1.3, 95% CI:1.1-1.5) was significantly associated with OS in a multivariable model (HR, 95%CI) adjusted for age (1.01, 1.00-1.03), sex (1.2, 0.9-1.7), type of HMA used before HSCT (1.0, 0.9-1.1), number of HMA cycles (1.0, 0.9-1.05), donor type (1.0, 0.9-1.1), and conditioning regimen used (1.3, 1.1-1.5). For OS, the IPSS-M significantly stratified pts assigned to the very high risk IPSS-R subgroup (p=0.009). However, the IPSS-M showed comparable performance to IPSS-R with c-index (95%CI): 0.597 (0.555-0.640) vs. 0.599 (0.554-0.643), respectively, for OS. When IPSS-M/IPSS-R were analyzed as continuous scores, the c-index (95%CI) for OS were: 0.606 (0.561-0.651) vs. 0.611 (0.559-0.662). When focusing on the higher risk group defined as IPSS ≥.1.5, the IPSS-M (c-index: 0.584) still had performance comparable to the IPSS-R (c-index: 0.606). Conclusions To our knowledge, this is the largest reported cohort in which IPSS-M performance was evaluated among pts with HMA-treated MDS and subsequently underwent HSCT. While the IPSS-M subgroups showed significant OS differences, the IPSS-M did not seem to substantially improve prediction when compared to the IPSS-R.

Outcomes of Patients Receiving Intensive Therapy for Acute Myeloid Leukemia Relapsed after/Refractory to Frontline Less-Intensive Therapy

Background: Hypomethylating agent (HMA) and venetoclax (Ven) frontline therapy for acute myeloid leukemia (AML) is astandard of care for patients (pts) deemed to be poor candidates for intensive induction due to age or fitness. However, given its attractive risk-benefit ratio, there is an increasing interest to extend the preference for HMA + Ven to other pts, including those who are fit for intensive therapy but with adverse risk disease. Unfortunately, most pts treated in this fashion will require future therapies for relapsed/refractory (R/R) disease and intensive therapy is given consideration mostly for pts with a path to allogeneic hematopoietic stem cell transplantation (alloHCT). Little is known about the outcomes of pts who receive intensive induction therapy after use of a frontline less-intensive regimen in the modern era. In this multi-center study, we seek to describe the experience with such a patient population and identify predictors of differential clinical outcomes. Methods: We conducted a multi-center, retrospective study of pts with AML treated with frontline less-intensive chemotherapy, followed by intensive induction chemotherapy for R/R disease. We first described the baseline characteristics of this cohort. Nominal variables were summarized with frequency and percentage while continuous variables were summarized with median and interquartile range (IQR). Overall response rate (ORR) was defined as complete remission (CR), complete remission with incomplete count recovery, or morphologic leukemia free state. Differences in ORR were analyzed with Fisher's exact test for nominal variables and Wilcoxon rank-sum test was used for continuous variables. Kaplan-Meier analysis was used to determine median overall survival (OS) after induction chemotherapy. Log-rank testing and Cox proportional hazard models were used to determine survival differences for nominal and continuous variables, respectively. Statistical significance was determined as p-value <0.05. Results: A total of 23 pts were included in this study. Median age at diagnosis was 64 years (IQR: 62-71). The majority of pts were male (n=12, 52%), white (n=20, 87%), and had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1 (n=18, 82%). The majority of pts (61%) at time of frontline therapy had AML arising out of MDS. As expected, the majority of pts had adverse risk ELN cytogenetics (n=16, 70%) with an enrichment for disease harboring TP53 mutation (n=6, 27%) and complex karyotype (n=9, 39%). Fifteen pts (65%) had frontline therapy with azacitidine backbone, 6 pts (26%) with decitabine; some pts received both before intensive therapy. The median number of cycles of frontline therapy was 2 (IQR: 2-5). Median WBC at time of R/R therapy was 1.9 x 10 9/L (IQR: 0.8-6.45), while hemoglobin was 8.4 g/dL (IQR: 7.5-9.45), platelets were 41 x 10 9/L (IQR: 19.5-116.5), and marrow blasts were 25% (IQR: 16.5-30%). The plurality of pts received CPX-351 as intensive R/R therapy (n=9, 39%). Other regimens included 7+3 (n=2, 9%), FLAG-Ida + Ven (n=2, 9%), HiDAC + Mitoxantrone +/- Ven (n=4, 17%) ( Table 1). ORR after intensive R/R therapy was 27% (n=6), with 23% achieving CR. CPX-351 after HMA + Ven was specifically associated with an ORR of 33% (CR rate 22%). Median OS after initiation was 5.8 months. Thirty- and 60-day mortality was 17% and 26%, respectively. Five patients (23%) proceeded to alloHCT ( Table 1). Univariate differences in response rate and median survival were analyzed for each of the aforementioned variables as illustrated in Table 1. While none of the covariates reached statistical significance for impacting ORR or OS, ECOG PS trended towards significantly impacting OS ( p=0.074) and the median OS among patients proceeding to alloHCT was numerically doubled (8.0 vs. 4.0 months, p=0.11) ( Figure 1). Conclusions: Intensive therapy for R/R AML after prior frontline less-intensive therapy was associated with an ORR rate of 27% and median OS of 5.8 months in our cohort. This approach may be an appropriate strategy for a subset of pts, particularly those eligible for alloHCT. The relatively small and heterogeneous nature of this cohort limits strong conclusions regarding efficacy. As the use of frontline HMA + Ven continues to expand, further studies with larger sample size are needed to determine which pts would and would not benefit from intensive induction therapy in the R/R setting.

Myelodysplastic Syndrome Hematopoietic Stem Cells Can Undergo Differentiation Trajectory Rewiring to Escape Venetoclax Vulnerability

Myelodysplastic syndromes (MDS) are incurable neoplasms that arise from early hematopoietic stem cells (HSCs). The standard of care for MDS is hypomethylating agent (HMA) therapy. However, the disease invariably fails these agents, resulting in fatal cytopenias or progression to acute myeloid leukemia (AML) with a dismal prognosis. We previously showed that the cellular hierarchy of MDS HSCs predicts the mechanisms of progression after HMA failure and can guide the design or choice of specific therapeutic approaches targeting these cells (Ganan-Gomez et al., Nature Medicine 2022). MDS HSCs in one of two differentiation states, long-term HSCs or lymphoid-primed multipotent progenitors, have a “common myeloid progenitor (CMP) pattern” or “granulocytic-monocytic progenitor (GMP) pattern” of differentiation. HSCs in these 2 differentiation states persist throughout the disease course and, driven by the recurrent activation of BCL2- or NF-κB-mediated survival pathways, respectively, expand at disease progression. In our preclinical studies, pharmacologically inhibiting these pathways depleted MDS HSCs and reduced tumor burden, which suggests that only patients with “CMP pattern” MDS may benefit from venetoclax-based therapies. Accordingly, patients with “CMP pattern” MDS, whose disease progressed after frontline HMA failure, enrolled in clinical trials of venetoclax-based therapy (NCT04160052, NCT04550442, or NCT04655755; n=28: 12 “CMP pattern” MDS and 16 “GMP pattern” MDS) had a shorter cumulative time to complete remission (P=0.012) and a longer relapse-free survival duration (14.0 months vs 5.2 months) than those with “GMP pattern” MDS did. Consistent with the hypothesis that venetoclax-based therapy selectively targets different HSC populations after HMA therapy failure, bone marrow (BM) HSC frequencies were significantly decreased at the time of remission after venetoclax-based therapy in “CMP pattern” MDS patients, but not in those with “GMP pattern” MDS. These results explain why “GMP pattern” MDS are resistant to venetoclax therapy. However, 8 of the 12 patients with “CMP pattern” MDS relapsed during venetoclax treatment and/or progressed to AML after an initial remission. In 2 patients with “CMP pattern” MDS, sequential flow cytometry and next generation sequencing analyses showed that the HSC hierarchy switched to “GMP pattern” MDS before venetoclax failure. This immunophenotypic hierarchical change was associated with the detection or expansion of STAG2- or RUNX1-mutant clones with isolated trisomy 8. To evaluate whether the immunophenotypic switch resulted from the distinct differentiation potential of early HSCs or from the aberrant expression of cell surface markers, we performed sequential single-cell RNA sequencing analyses of BM mononuclear cells isolated from the 2 “CMP pattern” MDS patients whose disease changed hierarchy before venetoclax failure. Our analyses revealed that after undergoing significant depletion during disease remission, HSCs expanded at therapy failure. Differential expression analysis showed that the expansion of STAG2- or RUNX1-mutant clones in the HSC compartment not only rewired MDS HSCs' differentiation state towards a granulo-monocytic-biased trajectory but also changed HSCs' survival dependency from BCL2-mediated anti-apoptotic pathways to TNFa-induced pro-survival NF-κB signaling, thus enabling HSCs to evade the cytotoxic effects of venetoclax (Fig. 1). The anti-apoptotic gene MCL1, a direct transcriptional target of NF-κB, was also significantly upregulated in HSCs at the time of progression, which suggests that the combination of venetoclax with an MCL1 inhibitor can overcome secondary failure to venetoclax. Together, these results reveal a novel mechanism of venetoclax resistance. HSCs under venetoclax therapy undergo survival pressure, which results in the expansion or acquisition of clones carrying specific mutations that change HSCs' survival dependencies (Fig. 2). Our study suggests that MDS patients receiving venetoclax-based therapy should be monitored at the molecular level and enrolled in clinical trials of other targeted agents before their disease undergoes clonal evolution and HSC hierarchical rewiring.

Prognostic heterogeneity and clonal dynamics within distinct subgroups of myelodysplastic syndrome and acute myeloid leukemia with TP53 disruptions.

TP53 aberrations constitute the highest risk subset of myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML). The International Consensus Classification questions the blast threshold between MDS and AML. In this study, we assess the distinction between MDS and AML for 76 patients with TP53 aberrations. We observed no significant differences between MDS and AML regarding TP53 genomics. Median overall survival (OS) was 223 days for the entire group, but prognostic discrimination within subgroups showed the most inferior OS (46 days) for AML with multihit allelic state plus TP53 variant allele frequency (VAF) > 50%. In multivariate analysis, unadjusted Cox models revealed the following variables as independent risk factors for mortality: AML (vs. MDS) (hazard ratio [HR]: 2.50, confidence interval [CI]: 1.4-4.4, p = 0.001), complex karyotype (HR: 3.00, CI: 1.4-6.1, p = 0.003), multihit status (HR: 2.30, CI 1.3-4.2, p = 0.005), and absence of hematopoietic cell transplant (HCT) (HR: 3.90, CI: 1.8-8.9, p = 0.0009). Clonal dynamic modeling showed a significant reduction in TP53 VAF with front-line hypomethylating agents. These findings clarify the impact of specific covariates on outcomes of TP53-aberrant myeloid neoplasms, irrespective of the diagnosis of MDS versus AML, and may influence HCT decisions.

Feasibility and Safety of Outpatient Hypomethylating Agent (HMA) + Venetoclax (Ven) Initiation +/- Ramp-up for Patients (pts) with Newly-Diagnosed Acute Myeloid Leukemia (AML)

Background: The feasibility/safety of outpatient (outpt) HMA + Ven administration and use of Ven ramp-up to target dose during cycle 1 (C1) for patients (pts) with newly-diagnosed AML is limited to small, single-center analyses of heterogeneous populations. Furthermore, appropriate pt selection for varying approaches is not well-described. Understanding these issues is crucial to efficient and cost-effective care delivery, especially considering the unique challenges older pts face. In this multi-center analysis, we examined the feasibility and safety of frontline HMA + Ven administration in the outpt setting as well as omission of Ven ramp-up during C1. Methods: We conducted a multi-center, retrospective study through the Consortium on Myeloid Malignancies and Neoplastic Diseases (COMMAND), a collaboration involving 10 academic institutions. A total of 272 pts with AML treated with frontline HMA + Ven were evaluated; pts presenting in spontaneous tumor lysis syndrome (TLS) or with incomplete data were excluded (n=24). We described the baseline characteristics of the overall study population. Continuous variables were summarized as a median with interquartile range (IQR), and categorical variables were reported as a frequency (percentage). Fisher's exact test was used for nominal data and Wilcoxon rank-sum testing was used for continuous variables Results: A total of 64 pts (23.5%) initiated HMA + Ven as outpts. Median age was 76 (IQR: 64-81.25) years, and the majority were male (n=35, 54.7%), white (n=54, 84.4%) and had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-1 (n=42, 73.7%). Cardiac comorbidities, prior stroke and diabetes were noted in 32.8%, 12.5% and 10.9% of outpts, respectively. Median total white blood cell count (WBC), marrow and peripheral blasts at presentation were 2.18 (IQR: 1.08-6.75), 38% (IQR: 20-53.5%) and 14% (IQR: 2-35.3%), respectively. Pre-treatment WBC, serum creatinine, uric acid and LDH were noted to be 2.45 (IQR: 1.48-3.98), 0.90 (IQR: 0.77-1.32), 5.05 (IQR: 4.18-5.9) and 212 (IQR: 171-314), respectively. All outpts had a pre-treatment WBC <20, uric acid <10 and creatinine <2; 8 pts (12.5%) had an LDH >500. Baseline characteristics are summarized in Table 1. When compared with pts receiving C1 of HMA + Ven as an inpt (n=208), outpts were found to have a lower presenting WBC (p=0.002), trend towards lower pre-treatment WBC (p=0.08) and a lower LDH (p=0.0002); pre-treatment uric acid was higher among outpts (p=0.027)(Table 1). There were no differences in disease with mutations with an influence on proliferative AML. Most outpts received allopurinol TLS prophylaxis (ppx); inpts more frequently had rasburicase ppx (13.1% vs. 3.4%, p=0.052). Most outpts received azacitidine (n=36, 56.3%) vs decitabine (5-day schedule)(n=28, 43.7%) with a similar distribution among inpts (p=0.25). Approximately half of outpts (51.6%) received anti-fungal ppx and required Ven dose reduction during C1. TLS was not observed in any outpts, compared with 10% in inpatients (p=0.0053) including 8% by Cairo-Bishop criteria (p=0.025). There was no difference in the median number of days admitted during the entirety of C1 between inpts and outpts (8 vs 5, p=0.16); 11% of outpts were eventually admitted during C1. Although treatment-related mortality (TRM = up to 90 days from start of C1) was higher among inpts, this was not statistically significant (12.8% vs 1.6%, p=0.20)(Table 1). Among outpts, approximately 1/3 had no Ven ramp-up (n=20, 31.3%). When compared with outpts with Ven ramp-up (n=44, 68.7%), there were no differences observed in age, ECOG PS, comorbidities, molecular characteristics, presenting or pre-C1 WBC, marrow/blood blasts, serum creatinine, uric acid, LDH, TLS ppx patterns or Ven dose-reduction for antifungal ppx (Table 2). More outpts without Ven ramp-up received decitabine (75% vs 35.9%, p=0.006). Median number of days admitted was higher among outpts with Ven ramp-up (5 vs 0, p=0.039) with one TRM attributed to infection in this group (p=0.99) Conclusions: Our study demonstrates that many pts with newly-diagnosed AML can safely receive C1 of HMA + Ven as an outpt, particularly those with a pre-treatment WBC <20, uric acid <10 and creatinine <2. We observed no TLS among outpts, including those without Ven ramp-up, which may be safely omitted in select pts. Prospective studies are needed to confirm these findings. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Evaluation of International Working Group 2006 Response Criteria in Patients with Higher-Risk Myelodysplastic Syndromes (HR-MDS) Treated with Hypomethylating Agent Monotherapy in the Frontline Setting

Evaluation of International Working Group 2006 Response Criteria in Patients with Higher-Risk Myelodysplastic Syndromes (HR-MDS) Treated with Hypomethylating Agent Monotherapy in the Frontline Setting

Outcomes of Patients with Chronic Myelomonocytic Leukemia (CMML) Treated with Hypomethylating Agents

Outcomes of Patients with Chronic Myelomonocytic Leukemia (CMML) Treated with Hypomethylating Agents

Frontline Azacitidine As a Bridge to Allogeneic Transplantation in Acute Myeloid Leukemia

Introduction: Treatment with the hypomethylating agent (HMA) azacitidine (AZA) has become a standard treatment option for older acute myeloid leukemia (AML) patients thought unfit for standard induction chemotherapy with infusional cytarabine and an anthracycline. AZA is generally well-tolerated, and carefully selected AML patients who achieve complete remission (CR) with frontline HMA therapy may subsequently improve to become suitable candidates for reduced intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (HCT) (Lübbert 2009). However, there are very limited data available regarding the use of AZA as a bridge to HCT in AML. The purpose of this study was to evaluate remission status and survival outcomes in patients treated with upfront AZA who undergo HCT.Methods: All AML patients at our institution diagnosed between December 2015 and October 2016 who were initially deemed unfit for intensive chemotherapy and received frontline AZA as a direct bridge to HCT were included in this analysis. Remission statuses after AZA therapy, immediately before transplant, and following transplant were evaluated and categorized as CR, CR with incomplete platelet recovery (CRp), CR with incomplete hematologic recovery (CRi), refractory, or relapsed. Descriptive statistics were used for categorical and continuous variables. The Kaplan-Meier method estimated overall survival (OS) and leukemia-free survival (LFS).Results: Ten patients treated with frontline AZA proceeded directly to HCT; by comparison, during the same period, 17 patients in this age range who received upfront AZA at our institution did not undergo HCT. Of those patients proceeding directly to HCT, there was a male predominance (80%), and median age at diagnosis was 70.5 years (range 60-77; Table 1). Of the 10 patients bridged to HCT, 3 were favorable risk by NCCN guidelines, 3 were intermediate risk, 3 were poor risk, and 1 had an unknown risk status. All patients received 75 mg/m2 of AZA administered daily intravenously on days 1-7 of a 28-day cycle, for a median of 6 cycles (range 4-11), without delays or dose reductions. Four patients received other chemotherapeutic agents concomitantly with azacitidine.During AZA therapy, 5 patients achieved CR, 4 obtained CRi, and 1 was refractory (despite exhibiting a reduction in bone marrow blasts). All patients maintained their respective remission statuses following AZA therapy until immediately prior to HCT. Nine patients underwent haploidentical peripheral blood HCT, and 1 underwent matched related peripheral blood HCT. All patients received a RIC regimen consisting of fludarabine, cyclophosphamide, and total body irradiation as well as post-transplant cyclophosphamide. One patient died from septic shock early during his transplant admission and was included in survival analyses but did not undergo post-HCT disease assessment. At their first disease assessment following HCT, 3 patients achieved CR, 3 obtained CRp, 2 exhibited CRi, and 1 had relapsed. For the aggregate patient cohort, Kaplan-Meier analyses revealed a 1-year OS rate of 86% and a 1-year LFS rate of 75% (Figure 1). Median OS was 19.2 months (95% CI [12.0, N/A]), and median LFS was not reached during the study. Median follow-up time from diagnosis was 14.5 months (range 9.6-19.7).Conclusions: Treatment with AZA was well-tolerated and adequately effective to yield remissions in an older patient population that typically experiences poor outcomes with intensive chemotherapy. Such patients may sufficiently improve while in remission to then proceed with HCT. Frontline AZA can thus be used as a successful bridge to HCT in selected elderly AML patients who were originally considered unfit for standard induction. These results require validation in a larger cohort. [Display omitted] DisclosuresGrunwald:Incyte: Consultancy, Research Funding; Genentech: Research Funding; Alexion: Consultancy; Pfizer: Consultancy; Amgen: Consultancy, Research Funding; Forma Therapeutics: Research Funding; Celgene: Consultancy; ARIAD: Consultancy; Cardinal Health: Consultancy; Janssen: Research Funding. Trivedi:Pharmacyclics: Consultancy, Honoraria.

Long-Term Outcome of Low-Dose Hypomethylating Agents in Lower-Risk Myelodysplastic Syndromes: A Randomized Phase 2 Study

Long-Term Outcome of Low-Dose Hypomethylating Agents in Lower-Risk Myelodysplastic Syndromes: A Randomized Phase 2 Study

Updated Results from a Phase II Study Combining Azacitidine and Pembrolizumab in Previously-Untreated Patients with Higher-Risk Myelodysplastic Syndrome

Updated Results from a Phase II Study Combining Azacitidine and Pembrolizumab in Previously-Untreated Patients with Higher-Risk Myelodysplastic Syndrome

A Predictive Model for Early Death after Frontline Hypomethylating Agents in Elderly Unfit Acute Myeloid Leukemia Patients: Results from the Pethema Group

INTRODUCTION: A sizable proportion of elderly acute myeloid leukemia (AML) patients receive frontline hypomethylating agents (HMAs), namely azacitidine (AZA) and decitabine (DAC), as they are deemed unfit for intensive chemotherapy (ICT) by their treating physicians. A foreseeable high early death (ED) rate and lack of overall survival (OS) benefit under ICT are the main drivers for this decision. Several groups have published different predictive tools for ED or OS in elderly patients receiving ICT but, since ED in patients treated by HMAs is lower, the research activity has been restricted to OS in this population. METHODS: 415 elderly AML patients (264 M, 152 F) aged 61-90 receiving frontline HMAs (AZA 297, DAC 118), either in daily practice or within clinical trials (AZA 27, DAC 17), with complete relevant clinical information (see Table I) were available from the PETHEMA epidemiologic AML registry (NCT02006004). We analyzed the predictive value for ED (8wk) of the prognostic factors for OS/ED in AML included in the Walter, MRC/LRF, ALFA and ALMA scoring systems, namely age, WBC count, performance status (PS), MRC 2010 cytogenetics, platelet count and secondary disease, as well as the type of HMA. The potential predictors were categorized following previous published models (Walter, MRC/LRF, ALFA, ALMA). Cumulative early death rate at 8 weeks was calculated by the life-time method and the relevant strata were tested for univariate significance by the Wilcoxon test. All significant covariates were included in a Cox multivariate regression model and those significant for death at 8wk were included in a new predictive tool (HMA-EDS). Patients were assigned randomly in a 1:1 ratio to a training cohort (TC) and a validation cohort (VC). The different scoring systems (Walter, MRC/LRF, ALFA, ALMA, HMA-EDS) were checked for their prognostic impact on ED. Finally the 95% CI for the expected death rate at 8wk for the different strata of the new model was calculated for the full patient series. RESULTS: 51 patients out of 415 died and 13 were lost to follow-up before day 56 (cumulative ED rate at 8wk 13%, 95%CI 9-17%). Age, cytogenetics, secondary AML, platelet count and type of HMA were not significantly associated to ED. PS and WBC count strata confirmed their prognostic utility both in univariate and multivariate analysis (Table II). We developed the HMA-EDS by adding WBC (cutoffs 10 and 50, scores 1/2/3) and PS (0-1/2-4, scores 0/1) that classified patients in low-risk (score 1-2/ 84.6% of patients) and high risk (3-4/ 15.4% of patients) strata. When the prognostic utility for ED in the TC and the VC for the different scoring AML systems were checked, only HMA-EDS predicted ED in both cohorts (see Table III). The new EDS discriminates 2 different strata for ED at 8wk in unfit AML patients treated by HMA (see Figure 1 &amp; Table III), namely a lower-risk group (ED rate 10%, 95% CI 6-14) and a high-risk group (ED rate 26%, 95% CI 14-38). CONCLUSIONS: WBC count and PS are the main predictors for ED in unfit AML patients treated by HMAs. A new tool (HMA-EDS) discriminates two different risk groups and supersedes other previously published prognostic systems (Walter's, Wheatley's MRC/LRF, ALFA and ALMA) for this purpose. This score could be useful to select patients for front-line HMA or even HMAs-based combination therapies, given that several cycles are usually needed to achieve a clinical response. We suggest that other patient-related covariates such as geriatric assessment be checked in future studies. Disclosures Ramos: Daiichi Sankyo: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria; Abbvie: Honoraria. Fernandez:Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Outcomes of Relapsed or Refractory Acute Myeloid Leukemia after Frontline Hypomethylating Agent with Venetoclax Regimens

Outcomes of Relapsed or Refractory Acute Myeloid Leukemia after Frontline Hypomethylating Agent with Venetoclax Regimens

Determinants of Outcomes of FLT3mut Acute Myeloid Leukemia with First Salvage Therapy

Determinants of Outcomes of FLT3mut Acute Myeloid Leukemia with First Salvage Therapy

Choice of Hypomethylating Agent (HMA) for Initial Treatment Does Not Influence Outcome or Survival for Therapy-Related Myeloid Neoplasms (t-MN)

Introduction: T-MN is a serious complication of prior chemotherapy and/or radiation therapy. In 2008, the World Health Organization created a new category for t-MN due to the distinct variance in etiology when compared to de novo myelodysplastic syndromes (MDS) or acute myelogenous leukemia (AML). Compared to de novo MDS/AML, t-MN characteristically has poor risk cytogenetics and a higher incidence of TP53 mutations which are both associated with inferior survival. Small, retrospective analyses have evaluated the efficacy of front-line HMA therapy for t-AML and t-MDS, with response rates of approximately 38% (Klimek et al. Leukemia Res, 2012 and Bally et al, Leukemia Res, 2013). However, the response duration (RD), progression-free survival (PFS), and overall survival (OS) outcomes are poorly characterized in t-MN treated with HMA. This retrospective study evaluates the efficacy and survival of t-MN patients (pts) treated with azacitidine (AZA) or decitabine (DAC) in the largest cohort analyzed to-date. Methods: Our cohort included pts with t-MN at Memorial Sloan Kettering Cancer Center treated with either AZA or DAC from January 1, 2002 to September 30, 2016. The primary objective was to compare the best overall response rate (ORR) between AZA and DAC, including complete remission (CR), marrow CR (mCR), hematologic improvement (HI), and partial response (PR). The best ORR was then compared to stable disease (SD), treatment failure (TF), and progressive disease (PD). Secondary objectives included OS, PFS, and RD. Responses were assessed using the 2006 MDS International Working Group (IWG) guidelines and 2003 AML IWG guidelines. We also assessed the impact of TP53 mutations on response to HMA and survival outcomes. Results: Of the 118 pts (56% male), 76 pts received DAC and 42 pts received AZA. Median age was 70 years (yrs) (range, 25-90). DAC recipients were younger (median 67 yrs, range, 25-85) compared to AZA (median 73 yrs, range, 42-90). More pts with AML were treated with DAC (n=27, 35.5%) and more pts with MDS were treated with AZA (n=36, 85.7%). Most MDS pts had Poor (19.3%) or Very Poor (42%) risk cytogenetics, resulting in a High (23.9%) or Very High (54.5%) overall IPSS-R risk category. Time to response was faster with DAC (9.4 weeks) versus (vs.) AZA (13.3 weeks) with more pts proceeding to hematopoietic cell transplant (HCT) in the DAC group (n=19, 25%) vs. AZA (n=3, 7.1%). Overall, there were no statistical differences in response between AZA and DAC when we analyzed combined TF/PD (45.2% and 32.9%, respectively), SD (14.3% and 25%, respectively), and combined CR/HI/PR (40.5% and 42.1%, respectively) with a p-value of 0.28 (Table 1). However, more patients receiving DAC achieved CR and mCR (18.4% and 14.5%, respectively) vs. AZA (4.8% and 7.1%, respectively) and AZA had a higher HI rate (28.6%) vs. DAC (5.3%). DAC pts also appeared to have higher TF rates (25%) vs. AZA (19%) with more PD in the AZA group (26.2%) vs. DAC (7.9%). Median OS was 10.9 months (mo) and PFS was 5.3 mo (Figure 1). There was no difference in median OS between AZA (11.2 mo) and DAC (10.9 mo, p=0.61) and no difference in the median PFS between AZA (5.1 mo) and DAC (5.3 mo, p=0.83). Lastly, there was no difference in median RD between AZA (4.5 mo) and DAC (3.4 mo, p=0.39). Of the 58 pts with known TP53 mutation status, 29 (50%) had ≥1 TP53 mutation(s). There was no difference in OS and PFS between mutant and wildtype TP53 pts, and no difference in survival between AZA and DAC recipients in the mutant TP53 cohort (Figure 2). Conclusions: This large, retrospective study showed no difference in the ORR between AZA and DAC. The faster response and higher rates of CR and mCR may favor the use of DAC as a bridge to HCT in eligible pts. Conversely, the higher rates of HI seen with AZA can improve the quality of life in MDS pts who are ineligible for HCT. Our results confirm prior reports of poor OS seen in t-MN. In our cohort, we showed no difference in survival outcomes between AZA and DAC. There was also no statistical difference in OS/PFS between DAC and AZA in mutant TP53 pts, however point estimates may indicate a pattern favoring DAC over AZA that needs to be explored in a larger sample size. Although we confirmed the efficacy of HMA in this difficult to treat population, response duration and survival outcomes remain poor. Development of more effective therapies that specifically target the biology of t-MN are needed to improve survival outcomes.

Impact of TP53 gene Mutation Clearance and Conditioning Intensity on Outcome in MDS or AML Patients Prior to Allogeneic Stem Cell Transplantation

Impact of TP53 gene Mutation Clearance and Conditioning Intensity on Outcome in MDS or AML Patients Prior to Allogeneic Stem Cell Transplantation

The Impact of PHF6 Mutations in Myelodysplastic Syndromes, Chronic Myelomonocytic Leukemia, and Acute Myeloid Leukemia

The Impact of PHF6 Mutations in Myelodysplastic Syndromes, Chronic Myelomonocytic Leukemia, and Acute Myeloid Leukemia