Impact of TP53 on outcome of patients with myelofibrosis undergoing hematopoietic stem cell transplantation.

TP53 mutations (TP53MTs) have been associated with poor outcomes in various hematologic malignancies, but no data exist regarding its role in patients with myelofibrosis undergoing hematopoietic stem cell transplantation (HSCT). Here, we took advantage of a large international multicenter cohort to evaluate the role of TP53MT in this setting. Among 349 included patients, 49 (13%) had detectable TP53MT, of whom 30 showed a multihit configuration. Median variant allele frequency was 20.3%. Cytogenetic risk was favorable (71%), unfavorable (23%), and very high (6%), with complex karyotype present in 36 patients (10%). Median survival of patients with TP53MT was 1.5 vs 13.5 years for those with wild-type TP53 (TP53WT; P < .001). Outcome was driven by multihit TP53MT constellation (P < .001), showing 6-year survival of 56% for individuals with single-hit vs 25% for those with multihit TP53MT vs 64% for those with TP53WT. Outcome was independent of current transplantation-specific risk factors and conditioning intensity. Similarly, cumulative incidence of relapse was 17% for single-hit vs 52% for multihit vs 21% for TP53WT. Ten patients with TP53MT (20%) presented as leukemic transformation vs only 7 (2%) in the TP53WT group (P < .001). Out of the 10 patients with TP53MT, 8 showed multihit constellation. Median time to leukemic transformation was shorter for multihit and single-hit TP53MT (0.7 and 0.5 years, respectively) vs 2.5 years for TP53WT. In summary, multihit TP53MT represents a very high-risk group in patients with myelofibrosis who are undergoing HSCT, whereas single-hit TP53MT alone showed similar outcome to patients with nonmutated TP53, informing prognostication for survival and relapse together with current transplantation-specific tools.

Splenic irradiation for myelofibrosis prior to hematopoietic cell transplantation: A global collaborative analysis.

Splenomegaly is the clinical hallmark of myelofibrosis. Splenomegaly at the time of allogeneic hematopoietic cell transplantation (HCT) is associated with graft failure and poor graft function. Strategies to reduce spleen size before HCT especially after failure to Janus kinase (JAK) inhibition represent unmet clinical needs in the field. Here, we leveraged a global collaboration to investigate the safety and efficacy of splenic irradiation as part of the HCT platform for patients with myelofibrosis. We included 59 patients, receiving irradiation within a median of 2 weeks (range, 0.9-12 weeks) before HCT. Overall, the median spleen size prior to irradiation was 23 cm (range, 14-35). Splenic irradiation resulted in a significant and rapid spleen size reduction in 97% of patients (57/59), with a median decrease of 5.0 cm (95% confidence interval, 4.1-6.3 cm). The most frequent adverse event was thrombocytopenia, with no correlation between irradiation dose and hematological toxicities. The 3-year overall survival was 62% (95% CI, 48%-76%) and 1-year non-relapse mortality was 26% (95% CI, 14%-38%). Independent predictors for survival were severe thrombocytopenia and anemia before irradiation, transplant-specific risk score, higher-intensity conditioning, and present portal vein thrombosis. When using a propensity score matching adjusted for common confounders, splenic irradiation was associated with significantly reduced relapse (p = .01), showing a 3-year incidence of 12% for splenic irradiation versus 29% for patients with immediate HCT and 38% for patients receiving splenectomy. In conclusion, splenic irradiation immediately before HCT is a reasonable approach in patients experiencing JAK inhibition failure and is associated with a low incidence of relapse.

Azacitidine, lenalidomide and donor lymphocyte infusions for relapse of myelodysplastic syndrome, acute myeloid leukemia and chronic myelomonocytic leukemia after allogeneic transplant: the Azalena-Trial.

Azacitidine (Aza) combined with donor lymphocyte infusions (DLI) is an established treatment for relapse of myeloid malignancies after allogeneic transplantation. Based on its immunomodulatory and anti-leukemic properties we considered Lenalidomide (Lena) to act synergistically with Aza/DLI to improve outcome. We, therefore, prospectively investigated tolerability and efficacy of this combination as first salvage therapy for adults with post-transplant relapse of acute myeloid leukemia, myelodysplastic syndromes and chronic myelomonocytic leukemia. Patients were scheduled for eight cycles Aza (75 mg/m2 day 1-7), Lena (2.5 or 5 mg, days 1-21) and up to three DLI with increasing T-cell dosages (0.5×106-1.5×107 cells/kg). Primary endpoint was safety, while secondary endpoints included response, graft-versus-host disease (GvHD) and overall survival (OS). Fifty patients with molecular (52%) or hematological (48%) relapse of myelodysplastic syndromes (n=24), acute myeloid leukemia (n=23) or chronic myelomonocytic leukemia (n=3) received a median of seven (range, 1-8) cycles including 14 patients with 2.5 mg and 36 with 5 mg Lena daily dosage. Concomitantly, 34 patients (68%) received at least one DLI. Overall response rate was 56% and 25 patients (50%) achieved complete remission being durable in 80%. Median OS was 21 months and 1-year OS rate 65% with no impact of type of or time to relapse and Lena dosages. Treatment was well tolerated indicated by febrile neutropenia being the only grade ≥3 non-hematologic adverse event in >10% of patients and modest acute (grade 2-4 24%) and chronic (moderate/severe 28%) GvHD incidences. In summary, Lena can be safely added to Aza/DLI without excess of GvHD and toxicity. Its significant anti-leukemic activity suggests that this combination is a novel salvage option for post-transplant relapse (clinicaltrials gov. Identifier: NCT02472691).

Acute myeloid leukemia-induced functional inhibition of healthy CD34+ hematopoietic stem and progenitor cells.

Acute myeloid leukemia (AML) is characterized by an expansion of leukemic cells and a simultaneous reduction of normal hematopoietic precursors in the bone marrow (BM) resulting in hematopoietic insufficiency, but the underlying mechanisms are poorly understood in humans. Assuming that leukemic cells functionally inhibit healthy CD34+ hematopoietic stem and progenitor cells (HSPC) via humoral factors, we exposed healthy BM-derived CD34+ HSPC to cell-free supernatants derived from AML cell lines as well as from 24 newly diagnosed AML patients. Exposure to AML-derived supernatants significantly inhibited proliferation, cell cycling, colony formation, and differentiation of healthy CD34+ HSPC. RNA sequencing of healthy CD34+ HSPC after exposure to leukemic conditions revealed a specific signature of genes related to proliferation, cell-cycle regulation, and differentiation, thereby reflecting their functional inhibition on a molecular level. Experiments with paired patient samples showed that these inhibitory effects are markedly related to the immunomagnetically enriched CD34+ leukemic cell population. Using PCR, ELISA, and RNA sequencing, we detected overexpression of TGFß1 in leukemic cells on the transcriptional and protein level and, correspondingly, a molecular signature related to TGFß1 signaling in healthy CD34+ HSPC. This inhibitory effect of TGFß1 on healthy hematopoiesis was functionally corrobated and could be pharmacologically reverted by SD208, an inhibitor of TGFß receptor 1 signaling. Overall, these data indicate that leukemic cells induce functional inhibition of healthy CD34+ HSPC, at least in part, through TGFß1, suggesting that blockage of this pathway may improve hematopoiesis in AML.

Treatment of myeloid malignancies relapsing after allogeneic hematopoietic stem cell transplantation with venetoclax and hypomethylating agents-a retrospective multicenter analysis on behalf of the German Cooperative Transplant Study Group.

Treatment of relapse after allogeneic hematopoietic stem cell transplantation (alloHSCT) remains a great challenge. Aiming to evaluate the combination of venetoclax and hypomethylating agents (HMAClax) for the treatment of relapse of myeloid malignancies after alloHSCT, we retrospectively collected data from 32 patients treated at 11 German centers. Venetoclax was applied with azacitidine (n = 13) or decitabine (n = 19); 11 patients received DLI in addition. HMAClax was the first salvage therapy in 8 patients. The median number of cycles per patient was 2 (1-19). All but 1 patient had grade 3/4 neutropenia. Hospital admission for grade 3/4 infections was necessary in 23 patients (72%); 5 of these were fatal. In 30 evaluable patients, overall response rate (ORR) was 47% (14/30, 3 CR MRDneg, 5 CR, 2 CRi, 1 MLFS, 3 PR). ORR was 86% in first salvage patients versus 35% in later salvage patients (p = 0.03). In 6 patients with molecular relapse (MR), ORR was 67% versus 42% in patients with hematological relapse (HR) (n = 24, p = n.s.). After a median follow-up of 8.4 months, 25 patients (78%) had died and 7 were alive. Estimated median overall survival was 3.7 months. Median survival of patients with HMAClax for first versus later salvage therapy was 5.7 and 3.4 months (p = n.s.) and for patients with MR (not reached) compared to HR (3.4 months, p = 0.024). This retrospective case series shows that venetoclax is utilized in various different combinations, schedules, and doses. Toxicity is substantial and patients who receive venetoclax/HMA combinations for MR or as first salvage therapy derive the greatest benefit.

Prognostic impact of pretransplant measurable residual disease assessed by peripheral blood WT1-mRNA expression in patients with AML and MDS.

OBJECTIVE: As peripheral blood (PB) Wilm's Tumor 1 (WT1)-mRNA expression is established as MRD-marker during conventional AML chemotherapy, impact of pretransplant WT1 expression remains unclear. Therefore, we aimed to assess prognostic impact of pretransplant WT1 expression on post-transplant outcome in patients with AML/MDS. METHODS: In 64 AML/MDS patients, pretransplant WT1 expression was retrospectively analyzed using a standardized assay offering high sensitivity, specificity, and a validated cut-off. Patients were divided into three groups determined by pretransplant remission and WT1 expression. Post-transplant outcome of these groups was compared regarding cumulative incidence of relapse (CIR), relapse-free (RFS), and overall survival (OS). RESULTS: Pretransplant forty-six patients (72%) showed hematologic remission, including 21 (46%) MRD-negative and 25 (54%) MRD-positive patients indicated by WT1 expression, while 18 refractory patients (28%) showed active disease. Two-year estimates of post-transplant CIR, RFS, and OS were similar in MRD-positive (61%, 37%, 54%) and refractory patients (70%, 26%, 56%), but significantly inferior compared with MRD-negative patients (10%, 89%, 90%). After multivariable adjustment, pretransplant MRD negativity measured by WT1 expression retained its prognostic impact on CIR (P = .008), RFS (P = .005), and OS (P = .049). CONCLUSIONS: PB WT1 expression represents a useful method to estimate pretransplant MRD, which is highly predictable for post-transplant outcome and may help improving peri-transplant management in AML/MDS patients.

Comparison between Upfront Transplantation and different Pretransplant Cytoreductive Treatment Approaches in Patients with High-Risk Myelodysplastic Syndrome and Secondary Acute Myelogenous Leukemia.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative treatment for patients with advanced myelodysplastic syndrome (MDS) and secondary acute myelogenous leukemia (sAML), but in the absence of prospective trials the impact of pretransplant cytoreduction is controversially discussed. We retrospectively analyzed the outcome of 165 patients with MDS and excess blasts (n = 126, 76%) and sAML (n = 39, 24%) according to a pretransplant strategy. Sixty-seven patients (41%) were directly transplanted (upfront group), whereas 98 patients (59%) had received pretransplant cytoreductive treatment (induction chemotherapy [CTX], n = 64; hypomethylating agents [HMAs], n = 34) resulting in a significantly higher complete remission rate in the CTX group (59% versus HMA 18%, P < .0001). Estimated rates of 5-year overall survival (OS) and relapse-free survival (RFS) for the entire group were 54% and 39%, respectively. The 5-year OS rates of the upfront, CTX, and HMA groups were 61%, 50%, and 45%, respectively (P = .116), whereas RFS rates were 38%, 41%, and 38% (P = .926). Cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM) did not differ between treatment groups. In the upfront group no difference regarding OS and RFS was seen with respect to pretransplant blast count (>10% versus <10%). In multivariate analyses type of pretransplant strategy did not have an effect on OS, RFS, CIR, and NRM, whereas cytogenetics (OS, RFS, CIR), reduced-intensity conditioning (OS, RFS, CIR), and an unrelated donor (RFS, CIR) were identified as negative predictors. When compared with the upfront group, 5-year OS was significantly lower in patients with CTX-refractory disease (34% versus 64%, P = .0346) and by clear trend in HMA nonresponders (42% versus 61%, P = .073), whereas RFS did not differ significantly. In further support of the concept, that pretransplant therapy may favor the selection of resistant clones, patients in the upfront group had a higher likelihood to respond to HMAs as salvage therapy for relapse in comparison with pretreated patients (complete remission, 58% versus 10%; P = .0005) and a higher 2-year OS rate after relapse (59% versus 19%, P = .0001). These data suggest that an upfront transplant strategy is at least not inferior to pretransplant cytoreduction and may be augmented by HMAs + donor lymphocyte infusion salvage therapy in case of relapse after allo-HSCT.

Relapse patterns and treatment strategies in patients receiving allogeneic hematopoietic stem cell transplantation for myeloid malignancies.

Allogeneic hematopoietic stem cell transplantation (aHSCT) cures a considerable number of patients with myeloid malignancies, but relapse is the most frequent cause of death. We retrospectively studied relapse rate, kinetics, treatment, and outcome after first aHSCT in 446 patients during a 13-year period. Relapse occurred in 167 patients after a median of 4.6 months (116 hematologic (HR), 38 molecular (MR), and 13 extramedullary relapses (XR)). Median survival after relapse was 8.4 months and 2-year overall survival was 25%. Regarding survival after relapse, type (MR/HR/XR) and timepoint of relapse ( 12 months), age ( 50), diagnosis (MDS/AML and sAML), and remission status at transplant (CR and untreated MDS vs. refractory disease) were relevant in univariate analyses, in multivariate analyses timepoint, and type of relapse, age, and diagnosis. One hundred fifty-six patients were treated, most frequently with hypomethylating agents (HMA, n = 109) or intensive chemotherapy (n = 12). Donor lymphocyte infusion (DLI) was administered to 99 patients. Second aHSCT was performed in three patients as first and in 21 as higher salvage treatment. A complete remission (CR) was achieved in 46 patients (30%). Among CR patients, 65% had received HMA and DLI. Median survival of patients achieving CR was 105 months and 2-year overall survival was 80%. We conclude that with HMA and DLI or second aHSCT, a substantial number of patients, who relapse after aHSCT, can re-achieve remission and long-term survival. Techniques to further improve the detection of minimal residual disease are urgently needed because early treatment of MR results in significantly better survival.

Spontaneous remission in a patient with very late relapse of acute myeloid leukemia 17 years after allogeneic blood stem cell transplantation.

Spontaneous remission (SR) of acute myeloid leukemia (AML) represents a rare phenomenon and is usually of short duration although long-term remissions are reported. Indeed, mechanisms underlying SR remain unclear, but it is suggested that immunactivation, e.g. caused by infections, plays an important role. Here we report on a patient who suffered from pneumonia and simultaneously experienced very late hematologic AML relapse seventeen years after allogeneic blood stem cell transplantation (allo-BSCT). Surprisingly in parallel to recovery from pneumonia peripheral blood count which previously showed pancytopenia, had normalized and bone marrow (BM) aspiration revealed spontaneous remission of AML. To the best of our knowledge we here report on the latest AML relapse after allo-BSCT experiencing SR.

Relapse of Acute Myeloid Leukemia after Allogeneic Stem Cell Transplantation: Prevention, Detection, and Treatment.

Acute myeloid leukemia (AML) is a phenotypically and prognostically heterogeneous hematopoietic stem cell disease that may be cured in eligible patients with intensive chemotherapy and/or allogeneic stem cell transplantation (allo-SCT). Tremendous advances in sequencing technologies have revealed a large amount of molecular information which has markedly improved our understanding of the underlying pathophysiology and enables a better classification and risk estimation. Furthermore, with the approval of the FMS-like tyrosine kinase 3 (FLT3) inhibitor Midostaurin a first targeted therapy has been introduced into the first-line therapy of younger patients with FLT3-mutated AML and several other small molecules targeting molecular alterations such as isocitrate dehydrogenase (IDH) mutations or the anti-apoptotic b-cell lymphoma 2 (BCL-2) protein are currently under investigation. Despite these advances, many patients will have to undergo allo-SCT during the course of disease and depending on disease and risk status up to half of them will finally relapse after transplant. Here we review the current knowledge about the molecular landscape of AML and how this can be employed to prevent, detect and treat relapse of AML after allo-SCT.

Wilms' Tumor 1 Gene Expression Using a Standardized European LeukemiaNet-Certified Assay Compared to Other Methods for Detection of Minimal Residual Disease in Myelodysplastic Syndrome and Acute Myelogenous Leukemia after Allogeneic Blood Stem Cell Transplantation.

Overexpression of the Wilms' tumor 1 (WT1) gene is informative in many patients with acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS) and is measurable in peripheral blood (PB). Despite these advantages, WT1 has not broadly been established as a marker for minimal residual disease (MRD) monitoring after allogeneic hematopoietic stem cell transplantation (allo-HSCT) due to limited patient numbers, differing sample sources, and nonstandardized in-house methods. To estimate the value of WT1 as an MRD marker, we serially quantified PB WT1 expression using a standardized European LeukemiaNet-certified assay in 59 patients with AML and MDS after allo-HSCT. We compared its performance with routine methods such as chimerism, XY-fluorescence in situ hybridization (FISH), disease-specific cytogenetic, and molecular analyses, which were accessible in 100%, 34%, 68%, and 37%, respectively. Twenty-four patients (41%) relapsed within a median of 126 days after allo-HSCT, and 20 of them showed at least 1 elevated WT1 value above the validated cutoff. The other 35 patients (59%) remained in complete remission, and only 1 patient had a transient increase in WT1 expression. This reflects a sensitivity of 83% and a specificity of 97% for WT1 and appears to be favorable compared with the sensitivities and specificities observed for chimerism (33% and 91%), XY-FISH (67% and 73%), cytogenetic (33% and 77%), and molecular (78% and 85%) analyses. Further supporting its predictive impact, elevated WT1 expression prompted an earlier BM biopsy and consecutively the diagnosis of relapse in 62% of patients. The results of this real-life experience imply that PB WT1 expression is measurable by a standardized assay and predicts imminent relapse after allo-HSCT with high sensitivity and specificity in most patients with AML and MDS.

Treatment of relapsed AML and MDS after allogeneic stem cell transplantation with decitabine and DLI-a retrospective multicenter analysis on behalf of the German Cooperative Transplant Study Group.

In contrast to the evidence regarding azacitidine (Aza), there is limited knowledge about the combination of decitabine (DAC) and donor lymphocyte infusions as salvage therapy for relapse after allogeneic stem cell transplantation (allo-SCT) so far. We retrospectively analyzed data of 36 patients with hematological (n = 35) or molecular relapse (n = 1) of acute myeloid leukemia (AML, n = 29) or myelodysplastic syndrome (MDS, n = 7) collected from 6 German transplant centers. Patients were treated with a median of 2 cycles DAC (range, 1 to 11). DAC was the first salvage therapy in 16 patients (44%), whereas 20 patients (56%) had previously received 1 to 5 lines of salvage therapy including 16 of them had been treated with Aza. In 22 patients (61%), a median of 2 DLI per patient (range, 1 to 5) was administered in addition to DAC. As a result, overall response rate was 25% including 6 complete remissions (CR, 17%) and 3 partial remissions (PR, 8%). Three patients within the first-line group achieved CR, while also 3 patients receiving DAC as second-line treatment reached CR including 2 patients with previous Aza failure. Median duration of CR was 10 months (range, 2 to 33) and no patient relapsed so far. The 2-year OS rate was 11% (± 6%) without any difference between first-line and pretreated patients. Incidence of acute and chronic graft-versus-host disease was 19 and 5%. Taken together, DAC exerts clinical efficacy in patients with AML or MDS relapsing after allo-SCT and is able to induce durable remissions in individual patients suggesting that DAC may be an alternative to Aza or even a second choice after Aza failure.

Sorafenib and azacitidine as salvage therapy for relapse of FLT3-ITD mutated AML after allo-SCT.

OBJECTIVE: Patients with acute myeloid leukemia (AML) carrying FLT3-ITD mutations (FLT3-ITD+) who relapse after allogeneic transplantation (allo-SCT) have a very dismal prognosis with the currently available treatment options. METHODS: We treated eight patients with FLT3-ITD+ AML who had relapsed in median 91 d (range, 28-249) following allo-SCT with a combination of the multikinase inhibitor sorafenib and the DNA methyltransferase inhibitor azacitidine (Aza). RESULTS: Patients received a median of five cycles of Aza (range, 2-9) and sorafenib with a median daily dosage of 750 mg (range 400-800) for 129 d (range, 61-221). Six of eight patients received donor lymphocyte infusions (DLI) with a median number of two DLI per patient (range, 1-4). Following this treatment, four patients (50%) achieved a complete remission and three of them a complete molecular remission. Median duration of CR was 182 d (range, 158-406), and two patients remain in ongoing remission for 406 and 168 d. Median overall survival was 322 d (range, 108-574 d) with three patients being currently alive. CONCLUSION: Taken together, the combination of sorafenib, Aza, and DLI shows promising efficacy and deserves further evaluation in larger patient groups.

Anti-T-lymphocyte globulin improves GvHD-free and relapse-free survival in myelofibrosis after matched related or unrelated donor transplantation.

Acute and chronic graft-versus-host disease (GvHD) are major complications of allogeneic hematopoietic cell transplantation (alloHCT). In vivo T-cell depletion with anti-T-lymphocyte globulin (ATLG) as part of the conditioning regimen prior to alloHCT is frequently used as GvHD prophylaxis, but data on its role in myelofibrosis is scarce. We took advantage of an international collaborative network to investigate the impact of ATLG in myelofibrosis undergoing first alloHCT. We included 707 patients (n = 469 ATLG and n = 238 non-ATLG prophylaxis). The cumulative incidence of acute GvHD grade II-IV was 30% for the ATLG group vs. 56% for the non-ATLG group (P < 0.001). Acute GvHD grade III-IV occurred in 20% vs. 25%, respectively (P = 0.01). Incidence of mild-to-severe chronic GvHD was 49% vs. 50% (P = 0.52), while ATLG showed significantly lower rates of severe chronic GvHD (7% vs. 18%; P = 0.04). GvHD-free and relapse-free survival (GRFS) at 6 years was 45% for the ATLG group vs. 37% for the non-ATLG group (P = 0.02), driven by significantly improved GRFS of ATLG in matched related and matched unrelated donors. No significant differences in risk for relapse, non-relapse mortality, and overall survival were observed. Multivariable modeling for GRFS showed a 48% reduced risk of GvHD, relapse, or death when using ATLG.

Improvements in Posttransplant Outcomes Over Two Decades in Older Patients with Acute Myeloid Leukemia in the EBMT ALWP Study.

PURPOSE: Acute myeloid leukemia (AML) is a disease of older patients. Progress in allogeneic hematopoietic cell transplantation (allo-HCT) allowed the delivery of allo-HCT to older patients. We assessed changes over time in transplant characteristics and outcomes in patients with AML ages 65 years and above. PATIENTS AND METHODS: We identified 7,215 patients with AML (median age 68 years, range 65-80) allografted between 2000 and 2021 in first complete remission (CR1; 64%), second or subsequent remission (CR2+; 14%), or active disease (22%). RESULTS: Median follow-up was 40 months. The 3-year cumulative relapse incidence (RI) gradually and significantly decreased from 37% to 31%, then to 30% (P = 0.001) over the three time periods (2000-2009; 2010-2014; 2015-2021), whereas nonrelapse mortality (NRM) decreased from 31% and 31% to 27% (P = 0.003). The 3-year leukemia-free survival (LFS) and overall survival (OS) gradually and significantly improved from 32% to 38%, and then to 44% (P = 0.001) and from 37% to 42%, and then to 49% (P = 0.001), respectively. In multivariate analysis, significant improvement in the RI, LFS, and OS were noted after 2015, whereas NRM was not significantly affected. This improvement was observed regardless of disease status at transplant. CONCLUSIONS: In older patients with AML, we observed an impressive improvement over time in posttransplant outcomes, mostly attributed to decreased RI rather than decreased NRM, and regardless of disease status at transplant. These large-scale, real-world data can serve as a benchmark for future studies in this setting and indicate that the opportunity for transplant for the elderly should be mandatory and no longer an option.

Allogeneic hematopoietic stem cell transplantation and pre-transplant strategies in patients with NPM1-mutated acute myeloid leukemia: a single center experience.

Patients with acute myeloid leukemia (AML) and nucleophosmin 1 gene mutations (NPM1mut) show a favorable prognosis with chemotherapy (CT) in the absence of negative prognostic genetic abnormalities. Between 2008 and 2021 64 patients with NPM1mutAML received alloHSCT because of additional adverse prognostic factors (1st line), inadequate response to or relapse during or after CT (2nd line). To expand the evidence in alloTX in NPM1mut AML, clinical and molecular data were retrospectively analyzed with respect to pre-transplant strategies and outcome. Patients with minimal residual disease negative (MRD-) CR at transplant had better 2-y-PFS and 2-y-OS (77% and 88%) than patients with minimal residual disease positive (MRD+) CR (41% and 71%) or patients with active disease (AD) at transplant (20% and 52%). The 2nd line patients with relapse after completing CT responded well to high dose cytarabine based salvage chemotherapy (salvage CT) in contrast to patients relapsing while still on CT (90% vs 20%, P = 0.0170). 2-y-PFS and 2-y-OS was 86% in patients who achieved a 2nd MRD- CR pre alloHSCT. Outcome in NPM1mutAML depends on disease burden at alloHSCT. Time and type of relapse in relation to CT are predictive for response to salvage CT.

Clinical and Cytogenetic Characterization of Early and Late Relapses in Patients Allografted for Myeloid Neoplasms with a Myelodysplastic Component.

An improved understanding of relapse kinetics is required to optimize detection and treatment strategies for the post-transplant relapse of myeloid neoplasms. Therefore, we retrospectively analyzed data from 91 patients allografted for MDS (n = 54), AML-MRC (n = 29) and chronic myelomonocytic leukemia (CMML, n = 8), who relapsed after transplant. Patients with early (<12 months, n = 56) and late relapse (>12 months, n = 35) were compared regarding patient-, disease- and transplant-related factors, including karyotype analyses at diagnosis and relapse. After a median follow-up of 17.4 months after relapse, late relapses showed improved outcomes compared with early relapses (2-yr OS 67% vs. 32%, p = 0.0048). Comparing frequency of distinct patient-, disease- and transplant-related factors among early and late relapses, complex karyotype (p = 0.0004) and unfavorable disease risk at diagnosis (p = 0.0008) as well as clonal evolution at relapse (p = 0.03) were more common in early than in late relapses. Furthermore, patients receiving transplant without prior cytoreduction or in complete remission were more frequently present in the group of late relapses. These data suggest that cytogenetics rather than disease burden at diagnosis and transplant-related factors determine the timepoint of post-transplant relapse and that upfront transplantation may be favored in order to delay relapse.

High Molecular and Cytogenetic Risk in Myelofibrosis Does Not Benefit From Higher Intensity Conditioning Before Hematopoietic Cell Transplantation: An International Collaborative Analysis.

There is no direct evidence to recommend specific conditioning intensities in myelofibrosis undergoing allogeneic hematopoietic cell transplantation, especially in the molecular era. We aimed to compare outcomes of reduced intensity (RIC) or myeloablative conditioning (MAC) transplantation in myelofibrosis with molecular information. The study included 645 genetically annotated patients (with at least driver mutation status available), of whom 414 received RIC and 231 patients received MAC. The median follow-up time from transplantation was 6.0 years for RIC and 9.4 years for MAC. The 6-year overall survival rates for RIC and MAC were 63% (95% confidence interval [CI], 58%-68%) and 59% (95% CI, 52%-66%; P = 0.34) and progression-free survival was 52% (95% CI, 47%-57%) and 52% (95% CI, 45%-59%; P = 0.64). The 2-year cumulative incidence of nonrelapse mortality was 26% (95% CI, 21%-31%) for RIC and 29% (95% CI, 23%-34%) for MAC (P = 0.51). In terms of progression/relapse, the 2-year cumulative incidence was 10% (95% CI, 5%-19%) for RIC and 9% (95% CI, 4%-14%) for MAC (P = 0.46). Higher intensity conditioning did not seem to improve outcomes for higher-risk disease, according to mutational, cytogenetic, and clinical profile. In contrast, patients with reduced performance status, matched unrelated donors, and ASXL1 mutations appeared to benefit from RIC in terms of overall survival.