Socié, Gèrard

PURPOSE Allogeneic hematopoietic cell transplantation (HCT) improves outcomes for patients with AML harboring an internal tandem duplication mutation of FLT3 ( FLT3-ITD) AML. These patients are routinely treated with a FLT3 inhibitor after HCT, but there is limited evidence to support this. Accordingly, we conducted a randomized trial of post-HCT maintenance with the FLT3 inhibitor gilteritinib (ClinicalTrials.gov identifier: NCT02997202 ) to determine if all such patients benefit or if detection of measurable residual disease (MRD) could identify those who might benefit. METHODS Adults with FLT3-ITD AML in first remission underwent HCT and were randomly assigned to placebo or 120 mg once daily gilteritinib for 24 months after HCT. The primary end point was relapse-free survival (RFS). Secondary end points included overall survival (OS) and the effect of MRD pre- and post-HCT on RFS and OS. RESULTS Three hundred fifty-six participants were randomly assigned post-HCT to receive gilteritinib or placebo. Although RFS was higher in the gilteritinib arm, the difference was not statistically significant (hazard ratio [HR], 0.679 [95% CI, 0.459 to 1.005]; two-sided P = .0518). However, 50.5% of participants had MRD detectable pre- or post-HCT, and, in a prespecified subgroup analysis, gilteritinib was beneficial in this population (HR, 0.515 [95% CI, 0.316 to 0.838]; P = .0065). Those without detectable MRD showed no benefit (HR, 1.213 [95% CI, 0.616 to 2.387]; P = .575). CONCLUSION Although the overall improvement in RFS was not statistically significant, RFS was higher for participants with detectable FLT3-ITD MRD pre- or post-HCT who received gilteritinib treatment. To our knowledge, these data are among the first to support the effectiveness of MRD-based post-HCT therapy.

Outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) for adult acute lymphoblastic leukemia (ALL) have improved over time. Studies have shown that total body irradiation (TBI) is the preferable type of myeloablative conditioning (MAC). However, outcomes based on central nervous system (CNS) involvement, namely CNS-positive versus CNS-negative, have not been compared. Here, we evaluated outcomes of 547 patients (CNS-positive = 96, CNS-negative = 451) who were allografted in the first complete remission (CR1) between 2009 and 2019. Primary endpoint was leukemia-free survival (LFS). Median follow-up was not different between the CNS-positive and CNS-negative groups (79 versus 67.2 months, P = 0.58). The CNS-positive group were younger (median age 31.3 versus 39.7 years, P = 0.004) and were allografted more recently (median year 2012 versus 2010, P = 0.003). In both groups, MAC was the preferred approach (82.3% versus 85.6%, P = 0.41). On multivariate analysis, the CNS-positive group had higher incidence of relapse (RI) (hazard ratio [HR] = 1.58 [95% confidence interval (CI) = 1.06-2.35], P = 0.025), but no adverse effect on LFS (HR = 1.38 [95% CI = 0.99-1.92], P = 0.057) or overall survival (OS) (HR = 1.28 [95% CI = 0.89-1.85], P = 0.18). A subgroup multivariate analysis limited to CNS-positive patients showed that a TBI-based MAC regimen resulted in better LFS (HR = 0.43 [95% CI = 0.22-0.83], P = 0.01) and OS (HR = 0.44 [95% CI = 0.21-0.92], P = 0.03) and lower RI (HR = 0.35 [95% CI = 0.15-0.79], P = 0.01). Another subgroup analysis in CNS-negative patients showed that MAC-TBI preparative regimens also showed a lower RI without a benefit in LFS or OS. While a MAC-TBI allo-HCT regimen may not be suitable to all, particularly for older patients with comorbidities, this approach should be considered for patients who are deemed fit and able to tolerate.

Abstract Background: A recent study from the Acute Leukemia Working Party of EBMT demonstrated that outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) for adults with acute lymphoblastic leukemia (ALL) have improved significantly over time and that total body irradiation (TBI) should be considered as the preferable type of myeloablative conditioning (MAC). This study, however, did not compare outcomes of allo-HCT in patients with CNS involvement (CNS-pos) vs. those without CNS disease (CNS-neg). Study population: Here, we evaluate post allo-HCT outcomes of 547 patients (CNS-pos at initial presentation=96, CNS-neg=451) who underwent the procedure in first complete remission (CR1) between 2009 and 2019 at an EBMT participating transplant center. The distribution of ALL subtypes were as follows: CNS-pos (Ph-neg B ALL=28%, Ph-pos B ALL=27%, and T-cell ALL=45%) and for CNS-neg (Ph-neg B ALL=21%, Ph-pos B ALL=44%, and T-cell ALL=35%), p=0.01. The primary endpoint was leukemia-free survival (LFS). Results: The median follow up was not statistically different between the CNS-pos (78.7 months) and the CNS-neg group (67.2 months), p=0.58. Patients in the CNS-pos group were younger (median age 31.3 vs. 39.7 years, p=0.004), received the procedure more recently (median year 2012 vs. 2010, p=0.003), were less likely to have a Karnofsky score of equal or higher than 90 (70.8% vs. 81.9%, p=0.017), or to have received peripheral blood stem cells (PBSC) (61.5% vs. 72.7%, p=0.028). The groups did not differ in regards to donor source (URD, 50% vs. 56.5%, p=0.24) or the intensity of the preparative regimen (MAC, 82.3% vs. 85.6%, p=0.41). In multivariate analysis, CNS-pos were associated with higher cumulative incidence of relapse (HR=1.58 (95%CI=1.06-2.35), P=0.025) and a trend for an inferior leukemia-free survival (LFS) (HR=1.38 (95%CI=0.99-1.92), p=0.057), but did not adversely impact overall survival (OS) (HR=1.28 (95%CI=0.89-1.85), p=0.18). A subgroup multivariate analysis limited to patients with CNS-pos showed that prescribing a TBI MAC regimen (vs. others) results in a lower cumulative incidence of relapse (HR=0.35 (95%CI=0.15-0.79), p=0.012) and better LFS (HR=0.43 (95%CI=0.22-0.83), p=0.01) and OS (HR=0.44 (95%CI=0.21-0.92), p=0.03). Use of PBSC (vs. BM) was also independently associated with better OS (HR=0.53 (95%CI=0.29-0.99), p=0.046). Conclusion: Notwithstanding the inherent limitations of registry data, particularly ascertaining the absence of CNS involvement in the CNS-neg group, our results show CNS involvement as an independent risk factor for relapse following allo-HCT. Our data support, nonetheless, the choice of a TBI-based MAC regimen in this group of patients but stresses the need for close monitoring of relapse after allo-HCT. Disclosures Labopin: Jazz Pharmaceuticals: Honoraria. Bazarbachi: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Hikma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees. Mielke: Immunicum: Other: Data safety monitoring board; DNA Prime SA: Speakers Bureau; Gilead/KITE: Other: Travel support, Expert panel ; Miltenyi: Other: Data safety monitoring board; Novartis: Speakers Bureau; Celgene/BMS: Speakers Bureau. Socie: Alexion: Research Funding. Huynh: Jazz Pharmaceuticals: Honoraria. Yakoub-Agha: Jazz Pharmaceuticals: Honoraria. Giebel: Janssen: Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau. Peric: Therakos, Servier, MSD, Astellas, Novartis, Abbvie, Pfizer: Honoraria. Mohty: Sanofi: Honoraria, Research Funding; Pfizer: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Jazz: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Celgene: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Astellas: Honoraria; Amgen: Honoraria; Adaptive Biotechnologies: Honoraria.

Abstract Isocitrate dehydrogenase (IDH) 1 and 2 mutations occur in 20% of acute myeloid leukemia (AML). Patients with AML carrying IDH1-2 mutations have a similar prognosis compared to patients without these mutations (DiNardo et al, AM J H, 2015). However, the impact of IDH1-2 mutations on patients with AML undergoing allogeneic hematopoietic stem cell transplantation (allo-HCT) is not well known. In this study, we investigate the prognostic impact of IDH1-2 mutational status on AML patients undergoing alloHCT in complete remission (CR). In this retrospective registry-based analysis, we identified 710 consecutive adult patients (46.2% female; median age: 58.5 years [range, 18-78]) with AML undergoing allo-HCT in CR between 2015 and 2019 at 85 EBMT participating centers. Cord blood, ex-vivo graft manipulated transplants, and patients with favorable cytogenetics were excluded. Median follow-up was 15 months [95% CI 13.4-16.6]. Patients were categorized based on IDH1-2 mutational status, with 300 (42%) mutated and 410 (58%) wild type. Six hundred and fifty-two (92%) and 58 (8%) patients had de novo and secondary AML, respectively, and 141 (20%) patients had poor-risk cytogenetics. IDH1-2 mutation was positively correlated with NPM1 mutation (40% in IDH1-2 mutated vs 27% in wild type, p=0.0001) and more frequently encountered in middle-aged patients (p=0.01). No correlation was noted between IDH1-2 and FLT3 mutation or other patient characteristics. Minimal residual disease (MRD) data was available for 344 patients, 53% of which were MRD-negative at transplant in both groups. Six hundred and twenty-three (88%) and 87 (12%) patients were in first and second CR at time of transplant, respectively. Patients received grafts from a matched sibling (24%), unrelated (62%), or haploidentical (14%) donor, and myeloablative conditioning (MAC) was used in 42%. Ninety-three percent of the patients received peripheral blood as the stem cell source. At day 180, the cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was significantly lower in IDH1-2 mutated compared to wild-type patients (22% vs 33%, p=0.002). No differences in chronic GVHD rates were noted between the 2 groups (39% vs 40%, p=0.87). The 2-year cumulative relapse incidence (RI) was significantly lower and the GVHD-free, relapse-free survival (GRFS) was also improved in IDH1-2 mutated compared to wild-type patients (14.4% vs 27%, p=0.001 and 47% vs 39%, p=0.006, respectively). This led to an improved leukemia-free survival (LFS) in IDH1-2 patients (69% vs 59%, p=0.01), however, it did not translate into an overall survival (OS) difference. No significant difference was noted in non-relapse mortality (NRM) between the 2 groups (17% vs 14.2%, p=0.26). These findings were confirmed in multivariate analysis. In fact, IDH1-2 mutation was associated with significant improvement in RI (hazard ratio [HR]=0.4 [95%CI 0.25-0.64], p=0.0001), LFS (HR=0.7 [95%CI 0.51-0.95], p=0.022), aGVHD II-IV (HR=0.63 [95%CI 0.45-0.87], p=0.005) and GRFS (HR=0.69 [95%CI 0.54-0.89], p=0.004). Conversely, the presence of adverse cytogenetics and undergoing allo-SCT in second CR increased the RI (HR=2.29 [95%CI 1.46-3.61], p=0.0003 and HR=2.84 [95%CI 1.64-4.91], p=0.0002, respectively) and were associated with a shorter LFS (HR=1.67 [95%CI 1.18-2.36], p=0.004 and HR=1.61 [95%CI 1.06-2.44], p=0.025) while reduced intensity (RIC) conditioning had a worse impact on OS compared to MAC (HR=1.56 [95%CI 1.07-2.29], p=0.022). Additionally, in the subgroup of patients with available MRD data, MRD positivity at transplant significantly increased RI (HR=2.15 [95%CI 1.09-4.23], p=0.027) with no impact on survival. In conclusion, our data suggest that the presence of IDH1-2 mutations acts as an independent prognostic factor and is associated with improved outcome in patients with AML in CR undergoing allo-HCT. Indeed, patients with IDH1-2 mutations had significantly lower rates of RI and aGVHD, which translated into improved LFS and GRFS. Nevertheless, patients with MRD positivity at time of transplant had significantly increased RI. Further studies investigating allo-HCT outcomes in IDH1-2 mutated patients with AML in the era of IDH inhibitors (both in the pre- and post-transplant setting) would help to further define the impact of these mutations in this setting and thus optimize an individualized treatment approach. Disclosures Labopin: Jazz Pharmaceuticals: Honoraria. Esteve: Abbvie: Consultancy; Pfizer: Consultancy; Astellas: Consultancy; Novartis: Research Funding; Novartis: Consultancy, Research Funding; Bristol Myers Squibb/Celgene: Consultancy; Jazz: Consultancy. Kröger: Novartis: Research Funding; Riemser: Honoraria, Research Funding; Sanofi: Honoraria; Neovii: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Gilead/Kite: Honoraria; Celgene: Honoraria, Research Funding; AOP Pharma: Honoraria. Blaise: Jazz Pharmaceuticals: Honoraria. Socie: Alexion: Research Funding. Ganser: Jazz Pharmaceuticals: Honoraria; Novartis: Honoraria; Celgene: Honoraria. Yakoub-Agha: Jazz Pharmaceuticals: Honoraria. Bazarbachi: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Hikma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees.