Begna, Kebede H.

Background: Chronic myelomonocytic leukemia (CMML) is a rare chronic myeloid malignancy with a poor prognosis. There are few epidemiologic studies on CMML. We studied population-based outcomes in CMML using the Surveillance, Epidemiology, and End Results (SEER) and the National Cancer Database (NCDB). Methods: The SEER 18 registries and NCDB Participant User File were used to identify patients with ICD-O-3 diagnosis code 9945/3 from 2004-2015. Incidence was identified using SEER and age-adjusted to the U.S. 2000 standard population. Causes of death were obtained and CMML-related death was defined as death from any myeloid disorder (CMML, acute monocytic leukemia, acute myeloid leukemia [AML], chronic myeloid leukemia, other myeloid/monocytic leukemia, and aleukemic, subleukemic, and NOS) to avoid misattribution. Relative survival (RS) was defined as the ratio of the proportion of observed survivors in a cohort of CMML patients to the proportion of expected survivors in a comparable set of individuals that did not have CMML, adjusting for the general survival of the US population for race, sex, age, and time when the diagnosis was established. Time to AML was calculated using the left-truncated life tables session and a 3 month latency period was used to prevent misattribution. Per the NCDB's system on classifying treatment, hydroxyurea, decitabine, and azacitidine are considered chemotherapy. The Kaplan-Meier method was used to calculate overall survival (OS), and Cox regression model was used to identify predictors of survival. Variables significant in univariate analysis (age, Charlson Deyo score [CDS], insurance type, and treatment facility type) were included in a multivariate analysis. Statistical analyses were performed using SAS version 9.0. Results: In the SEER database (n=4437), the median age at diagnosis was 76 years (interquartile range [IQR] 68-83) and 2,783 patients (63%) were male. Incidence rates (1 case/1,000,000 individuals) were as follows: overall 4.4, male 6.6, female 2.9, Non-Hispanic White 4.9, and Non-Hispanic Black 3.3. The incidence did not significantly change from 2004 to 2015. With a median follow up of 5.8 years (95% CI: 5.5-6.3), the median OS was 1.3 years (95% CI: 1.3-1.4). 3635 patients (82%) died. Among those who died, 2016 patients (55%) deaths were CMML-related. When comparing CMML patients to the US general population, 3,156 patients were matched to the expected survival tables. In the general U.S. population, the expected survival for 12, 24, 36, 48 and 60 months was 95.6%, 91.3%, 87.1%, 83.1%, and 79.2%, respectively. In contrast, the RS for patients with CMML at the same time points was 63.6%, 46.2%, 35.2%, 28.8%, and 23.1% (Figure 1). 229 patients (5.2%) progressed to AML. The median time to AML was 1.2 years (IQR 0.6-2.3). In NCDB (n=6403), the median age at diagnosis was 74 years (IQR 66-82). With the median follow up of 6 years (95% CI 3.5-9), the median OS was 1.3 years (95% CI 0.4-3.3). The distribution of CDS score 0, 1, and >1 was 4518 (71%), 1193 (18%), and 692 (11%) respectively. 4687 (77%) had government insurance, while 1399 (23%) had private insurance. 3750 (60%) were treated at a non-academic center. The year of diagnosis was associated with improved OS (HR 0.99, 95% CI: 0.98-0.99). Patients who were diagnosed in 2012-2015 had improved OS compared to patients diagnosed in 2004-2007 (HR 0.89, 95% CI 0.83-0.95) with OS at 1- and 5- years being 60% and 16% (2012-2015) vs. 56% and 17% (2008-2011) vs. 53% and 15% (2004-2007) respectively. 3029 (48%) patients received chemotherapy, while 270 (4%) patients received stem cell transplant as the first-line therapy. The median time to chemotherapy from diagnosis was 19 days (IQR 6-43). OS at 1-, 5-, and 10-years was 57%, 18%, and 4% (no chemotherapy), 56%, 14%, and 7% (received chemotherapy), 79%, 44%, and 38% (received stem cell transplant), and 56%, 15%, 5% (no stem cell transplant). OS curves are shown in Figure 2. Factors independently predicting inferior OS were age ≥ 65 years at the time of diagnosis (p<0.001), CDS ≥ 1 (p<0.001), government insurance (p<0.001), and treatment at a non-academic center (p<0.001) (Table). Conclusion: Despite an improvement in survival over the years, CMML continues to be a cause of significant morbidity and mortality. Older age, CDS ≥ 1, government insurance, and treatment at non-academic facilities were predictive of inferior survival. Disclosures Shah: Dren Bio: Consultancy.

AbstractVenetoclax and hypomethylating agent (HMA) combination therapy is FDA‐approved for elderly or unfit acute myeloid leukemia (AML) patients unable to withstand intensive chemotherapy. The primary objective of the current study was to impart our institutional experience with the above regimen, outlining response, survival outcomes, and its determinants amongst 86 treatment‐ naïve and relapsed/refractory AML patients. A total of 44 treatment‐naïve AML patients, median age 73.5 years, enriched with secondary, therapy related and ELN adverse risk disease (n = 27) were studied. The CR/CRi rates of 50% (22 of 44 patients) were superior to 23% in a matched AML cohort treated with HMA alone (P = .005). Response rates were similar with TP53, FLT3, NPM1 and IDH mutations (P = .31). Moreover, CEPBA mutations (P = .03) and neutropenia (P = .05) emerged as predictors of complete response. Survivalwas prolonged in patients achieving CR/CRi (17 vs 3 months without CR/CRi, P < .001; conversely adverse ELN risk portended inferior survival. Amongst 42 relapsed/refractory AML patients, half received ≥2 prior therapies excluding transplant, and 15 (35.7%) had received HMA. A group of 14 patients (33.3%) attained CR/CRi; age > 65 years, AML with myelodysplasia, JAK2, DNMT3A, and BCOR mutations predicted complete response. Survival distinctions were based on CR/CRi (median survival 15 vs 3 months with/without CR/CRi; P < .001), and TP53 mutation status (P = .04). In summary, we corroborate existing reports demonstrating superior response and prolonged survival with venetoclax and HMA in treatment ‐naïve and relapsed/refractory AML patients regardless of genotype. Additionally, we identify unique predictors of response to therapy which require validation.

AbstractQTc interval prolongation can lead to life‐threatening complications such as Torsade de Pointes (TdP), ventricular tachycardia (VT) and sudden cardiac death (SCD). It can occur with tyrosine kinase inhibitors (TKIs) but comparative real‐world analyses on the incidence and complication rates are scarce. We retrospectively reviewed all cancer patients treated with TKI therapy at Mayo Clinic between January 2005 and December 2018 and had at least two ECGs (before and after TKI). For each TKI type, we determined the administration rate and incidence of QTc prolongation. QTc prolongation was defined as a corrected QT interval (by Fridericia formula) ≥450 ms in men and ≥470 ms in women. A total of 618 cancer patients were included with 902 TKI administrations, of which 654 (72.5%) were accounted for by pazopanib, sunitinib, imatinib, nilotinib and dasatinib. QTc prolongation (any grade) was reported in 28.8%, most commonly with nilotinib (38.7%) and dasatinib (41.7%). A QTc interval ≥500 ms and a QTc increase ≥60 ms was documented in 46 and 63 administrations, respectively. Life‐threatening toxicity was seen in 14 cases (5.4% of QTc prolongation cases) including VT in 9, SCD in 3 and TdP in two administrations. The response to QTc prolongation was: discontinuation in 68%, dose reduction in 13.5%, temporary hold in 8.1% and no action in 10.4%. In conclusion, QTc prolongation with TKI therapy is very common (∼1/3 of cases) and in 5% (1.7% overall) associated with life‐threatening complications. These data support recommendations for careful ECG monitoring in cancer patients undergoing TKI therapy.

e18549 Background: Many vitamin deficiencies can cause anemia. It is prudent prior to diagnosing a myeloid neoplasm, to check for vitamin deficiencies and correct them. Myelodysplastic syndromes with ring sideroblasts (MDS-RS) are associated with anemia. Pyridoxine (Vit B6) replacement may improve anemia found in sideroblastic anemia. The study was to determine how frequently Vit B6 was assessed, replaced and impact replacement had on outcomes in MDS-RS. Methods: Study subjects were from the Mayo Clinic Myelodysplastic syndrome (MDS) database which contains 1315 patients (pts). Appropriate IRB approval was obtained. Diagnosis of MDS and its sub-classification was done according to World Health Organization 2016 criteria. A response was any improvement in hemoglobin. Overall survival (OS) estimates were calculated using Kaplan-Meier curves and univariate and multivariate analysis was done using JMP software version 13. Results: Among 1315 pts with MDS, 161 pts had a diagnosis of MDS-RS. Median age was 73, and 55 (34%) pts were females. Thirty-nine (36%) pts had very low, 53 (50%) low, 9 (8%) intermediate, 3 (3%) high, and 2 (1%) had very high revised international prognostic score. The median white blood cell count was 5.4 x109, platelet count was 255 x109, and hemoglobin was 9.9 gm/dL. Five pts (3%) had a Vit B6 levels done; out of whom, 4 (80%) were not Vit B6 deficient. Among 42 (26%) pts who had Vit B6 replacement, 21 (50%) had no response, 4 (10%) had a response and 17 (40%) had unknown response. 103 (64%) of the pts were transfusion independent (TI). Overall survival in pts who are transfusion dependent was 68 months compared to 85 in pts who are TI (Wilcoxon P =.03). There was an improvement in OS in the group that had Vit B6 replacement compared to the group with no Vit B6 replacement (92 months vs 68 months, Wilcoxon P =.07). Response to Vit B6 replacement did not show OS benefit. Acute Leukemia transformation in Vit B6 replacement was 2% and 6% in pts. who did not have Vit B6 replacement (P= .4). Conclusions: Vit B6 was not checked often in MDS-RS pts. There was a borderline improvement in OS in Vit B6 replacement group (p= .07). Response did not affect OS. A larger prospective study is needed to study Vit B6 role in MDS-RS.

7094 Background: Obesity is associated with comorbidities that could cause negative outcome upon delivering intensive care. In pediatric AML patients (pts), obesity was associated with more toxicity and worse prognosis. Here, we study Body-Mass Index (BMI) impact on clinical outcome of adult AML pts. Methods: A total of 180 adult pts with AML between 2003-2011 were enrolled. Retrospective data included demographics, labs, cytogenetics and outcome. LeukemiaNET Standardization (LNS), complete remission (CR), overall survival (OS) and relapse free survival (RFS) were obtained (Dohner E, Blood 2010). BMI of 25-30 was defined as overweight, while >30 as obesity. Fischer’s and Wilcoxon tests were used for comparatives between groups, cox proportional hazards and logistic regression for associations for OS/RFS and CR, Kaplan-Meier test for OS and RFS estimates via JMP software V9.0. IRB approval was obtained according to Helsinki declaration. Results: The median age was 63 years, with 115 (64%) were men. Of 159 pts, karyotype was favorable, Intermediate I, II and adverse in 21 (13%), 76 (48%), 23 (%14) and 39 (25%) pts respectively. Median BMI was 28.2 (range 16.8-47.8). 48 (26%) had normal BMI, 62 (34%) were overweight, and 70 (38%) were obese. At diagnosis, BMI classes were not associated with age, sex, glucose, white blood count (WBC), platelets, blasts, ECOG status, LNS, FLT3/NPM1 status; nor treatment toxicities, CR rates, or relapse after CR. BMI classes were associated with presence of concomitant comorbidities (p=0.047) and glucose levels (p=0.044). In univariate analysis, overweight (OR=1.8, p=0.16) and obesity (OR=1.9, p=0.13) did not affect CR rates. On adjusting for age, sex, LNS, WBC and blast count at diagnosis, only overweight pts had a significant higher CR (76% vs 63%) rates (OR=2.99, p=0.043). OS and RFS were not associated with BMI in univariate (p=0.51) and multivariate (p=0.32) models. Median OS and RFS were not different across BMI subgroups (p=0.52 and 0.59). Conclusions: BMI subgroups showed no correlation with treatment toxicity, LNS, relapse rates, OS or RFS. This should encourage giving therapy to pts regardless of their BMI status. Overweight was associated with better CR rates despite increased concomitant morbidities.

6614 Background: CDKN2A locus on chromosome 9p21 is implicated in altered molecular pathways leading to leukemogenesis as a tumor suppressor by inhibiting the proliferative kinases CDK4/CDK6 and blocking the cell-cycle division during G1/S phase. Deletion of CDKN2A locus is frequently seen in ALL, although prognostic significance remains unclear. Methods: Retrospective chart review at Mayo Clinic between 8/2005-11/2011 was performed on adult B-ALL patients (pts) who underwent fluorescent in situ hybridization (FISH) studies at diagnosis. Survival estimate was calculated using Kaplan-Meier statistics. Event-free survival (EFS) was defined as time between diagnosis and induction failure, relapse, or death, while overall survival (OS) as time between diagnosis and death Results: Out of 27 pts who had FISH studies for CDKN2A, 15 (56%) pts had CDKN2A deletions (8 homozygous/7 hemizygous), while 12 (44%) pts had diploid cytogenetics (none had abnormalities of MLL, bcr/abl fusion or CDKN2A deletion on FISH). There was no significant difference in median age, gender, WBC, hemoglobin, platelet count, LDH or complete remission (CR) rate (p=0.924) between the two groups. CDKN2A-deleted pts had higher circulating blasts (34% vs 16%, p=0.017). Of 13 CDKN2A-deleted pts, chromosome 9p was intact in 9 (69%) pts using routine cytogenetics. In the CDKN2A-deleted group, allogeneic stem cell transplant (ASCT) was performed in 7 (47%) pts at first CR and 1 at second CR. Four of 15 (27%) CDKN2A-deleted pts also had bcr/abl fusion. Five-year EFS was poorer in CDKN2A-deleted pts compared to normal FISH group (22% vs 60%, p=0.042), while 5-year OS was 72% vs 60% (p=0.308), respectively. Excluding the 4 bcr/abl fusion pts, 5-year EFS was still statistically significant (p=0.008). In the CDKN2A deleted group, both 5-yr EFS (80% vs 0%, p=0.006) and OS (100% vs 42%, p=0.016) were significantly superior in pts who received ASCT. Conclusions: CDKN2A deletions predict earlier relapse in pts with B-ALL. Majority of 9p abnormalities were only found by FISH testing and missed by conventional cytogenetics. In CDKN2A deleted pts, ASCT gave overall survival advantage. Further investigation through larger cohorts of pts is needed to validate these findings.