ALBERT

Description: Abstract 3542 The prognosis of acute promyelocytic leukemia (APL) has improved markedly over the last two decades. Clinical trials have demonstrated excellent survival of patients receiving anthracycline-based chemotherapy in combination with all-trans-retinoid acid (ATRA). It is not clear whether the excellent survival results demonstrated in clinical trials during recent years, also do apply to unselected patients including elderly and frail patients for whom a clinical trial may not be available. In order to investigate survival and death rates in APL over the course of treatment, we conducted a retrospective analysis of survival in 105 consecutive APL-patients diagnosed in Denmark January 2000 through June 2012. Data were retrieved from the Danish National Acute Leukemia Registry which covers 95 – 100 % of all acute leukemia cases diagnosed in Denmark since January 2000 (not including children). A diagnosis of APL was confirmed in 105 (3.9 %) of 2726 adult patients (age ≥ 15 years) with acute myeloid leukemia (AML) diagnosed in Denmark during the 12½ year period. This corresponds to an incidence rate of 1.53 APL cases per million inhabitants per year. The diagnosis of APL was based upon cytogenetic analysis (performed in 96 (91 %) of cases), and/or interphase FISH (iFISH), and/or RT-PCR in a total of 100 cases. In 5 cases clinical signs and morphological changes in bone marrow were highly suggestive of APL and these cases were, thus, deemed to have APL. Median age at diagnosis of APL was 50 years (range 15 to 83 years) and median leukocyte count was 2.65 (range 0.2 to 99.0 × 109/L). In 104 patients with data available for analysis, very early death (VED, within the first week from the date of diagnostic bone marrow) occurred in 10 cases (9.6 %), and early death (ED, death within 30 day from diagnosis) occurred in 22 (21 %) cases. Death between day 30 and 5 years from diagnosis occurred in 11 cases. No deaths were seen after 5 years from diagnosis. For all patients, estimated overall survival at 10 years was 65 % (Figure 1). Patients surviving beyond day 30 from day of diagnosis (82 cases) had an excellent overall survival of greater than 80 % at 10 years (Figure 2). Survival of patients were strongly correlated with WHO-performance status whereas age over 50 years and presenting leukocyte count greater than 10 × 109/L could not be definitely associated with inferior survival (Table 1 and Figure 3). Table 1. Factors of importance to survival in unselected APL-patients Probability of overall survival (Univariate Cox Regression, nevaluable= 104) Probability of overall survival (multivariate Cox Regression, nevaluable= 101) Variable Hazard ratio 95% CI of HR P value Hazard ratio 95% CI of HR P value Age (≤50 vs. 〉50 years) 2.17 1.07–4.42 0.03 1.44 0.67–3.09 NS WHO performance status (0–1 vs. ≥2) 5.20 2.57–10.5 〈 10−4 4.06 1.88–8.78 〈 10−4 WBC (≤10 × vs.〉10 × 109/L) 1.76 0.86–3.61 NS 1.62 0.79–3.33 NS From this population-based analysis we conclude that early death continues to be the predominant hazard to patients with APL. Two thirds of deaths in APL-patients do occur during the first month from diagnosis. Patients with a poor performance status at disease presentation carry a particularly dismal prognosis. For all APL-patients, every possible effort should be made to facilitate prompt diagnosis and speedy initiation of treatment with ATRA and anthracycline-based chemotherapy. When timely applied, currently available treatments are highly effective and result in cure in a high proportion of patients including elderly patients and patients with high leukocyte count at time of disease presentation. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction One third of patients with myelodysplastic syndrome (MDS) will relapse after allogeneic stem cell transplantation (SCT), with a dismal prognosis. Early detection of relapse enables pre-emptive treatment and may potentially reduce relapse risk, but is limited by the lack of sensitive markers for minimal residual disease (MRD). We developed a pipeline where patient-specific mutations, as determined by a myeloid next generation sequencing (NGS) panel are tracked using sensitive digital droplet PCR (ddPCR). Method We designed a prospective Nordic study (NMDSG14B; NCT02872662) enrolling all patients with MDS, mixed MDS / MPN or AML with myelodysplasia related disease and 〈 30% marrow blasts undergoing SCT in the Nordic region. We hypothesized that personalized MRD detection by ddPCR can predict clinical relapse earlier than conventional methods. Patients were included before SCT and serial bone marrow samples were collected before, and 1 and 3 months post SCT, and thereafter every third month for 2 years or until relapse or death. Blood samples were collected monthly. The MRD results were not available for the treating physicians. MRD positivity was defined based on the background noise of the specific ddPCR-assays and varied between 0.05-0.1% VAF. Results Three-hundred and sixteen patients were screened between 2016 and 2020, of which 19 were excluded due to lack of mutation or disease progression preventing SCT. We here present data of 254 patients followed ≥ 6 months after SCT. Median age was 64 (18-78) years and 59% were male. Most WHO subgroups of MDS (n=166), MDS/MPN (n=39), AML (n=8) and therapy-related disease (n=41), were represented. Risk profile according to IPSS-R was very low (n=13), low (n=32), intermediate (n=46), high (n=60) and very high (n=32). The majority of patients received pre-SCT treatment consisting of HMA (n=159) and / or intensive chemotherapy (n=59) while 60 patients did not receive disease-modifying treatment prior to SCT. The most common mutations were ASXL1 (n=69), TET2 (n=58), SRSF2 (n=57) and TP53 (n=44). No mutation was identified in 10 pts, and NGS data is still pending for 11 patients. After a median follow-up of 436 days, estimated 2 years overall survival and relapse free survival were 72% and 63%, respectively. Cumulative incidence of NRM and relapse at 2 years was 16% and 20%, respectively. Forty-six patients relapsed after a median of 170 (53-733) days, and the estimated median survival following relapse was 197 days. The most common pre-SCT mutations in the relapsed cohort were TP53 (n=19), DNMT3A (n=11) and RUNX1 (n=9). Thirty-seven patients died due to non-relapse mortality (NRM) after a median of 83 (4-754) days. To date, MRD results are available for 64 patients. Relapse was preceded by positive MRD in 14 out of 15 patients a median of 79 (21-173) days before clinical relapse. The 15th patient had an extra-medullary relapse only. Borderline positive MRD samples 〈 0.2% VAF within 100 days after SCT followed by negative samples were seen in 11 non-relapse patients. Twenty-four of 37 patients in continuous complete remission (CCR) were consistently MRD neg. Six CCR patients had positive MRD after 100 days; two with transient borderline peaks ( 0.1%, which turned negative when the patients developed GVHD; one patient with slowly decreasing MRD which turned negative first after 1 y, and finally one patient with prevailing KIT mutation (〉700 days post-SCT) despite negative BCOR and STAG2. Two MRD+ patients died from NRM without showing signs of clinical relapse. Discussion In summary, we show that our pipeline of personalized MRD-assessment, based on patient-specific mutations is feasible with a high sensitivity to predict relapse. An update of study progression will be presented at the meeting. Figure 1 Disclosures Illman: Sanofi-Genzyme: Other: Travel Support; Celgene: Other: Travel Support. Mielke:DNA Prime: Honoraria, Other: received via my institution , Speakers Bureau; KIADIS Pharma: Honoraria, Other: received via my institution , Speakers Bureau; Miltenyi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: received via my institution , Speakers Bureau; Kite/Gilead: Honoraria, Other: received via my institution , Speakers Bureau; Bellicum: Honoraria, Other: received via my institution, Speakers Bureau; Novartis: Honoraria, Other: received via my institution, Speakers Bureau; Celgene/BMS: Honoraria, Other: received via my institution , Speakers Bureau. Ebeling:Accord Healthcare: Other: Travel Support; Amgen: Other: Travel Support; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support; Otsuka Pharma Scandanavia AB: Consultancy, Membership on an entity's Board of Directors or advisory committees.