Distinct factors determine the kinetics of disease relapse in adults transplanted for acute myeloid leukaemia

Survival after allogeneic transplantation according to pretransplant minimal residual disease and conditioning intensity in patients with acute myeloid leukemia

Background

The measurement of minimal residual disease (MRD) by multiparametric flow cytometry (MFC) before hematopoietic stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML) is a powerful prognostic factor. The interaction of pretransplant MRD and the conditioning intensity has not yet been clarified.

Objective

The aim of this study is to analyze the transplant outcomes of patients with AML who underwent HSCT in complete remission (CR), comparing patients with positive MRD (MRD+) and negative MRD (MRD-) before HSCT, and the interaction between conditioning intensity and pre-HSCT MRD.

Study design

We retrospectively analyzed the transplant outcomes of 118 patients with AML who underwent HSCT in CR in a single institution, comparing patients with MRD+ and MRD- before HSCT using a cutoff of 0.1% on MFC, and the interaction between conditioning intensity and pre-HSCT MRD.

Results

Patients with MRD+ before HSCT had a significantly worse 2-year (2y) event-free survival (EFS) (56.5% vs. 32.0%, p = 0.018) than MRD- patients, due to a higher cumulative incidence of relapse (CIR) at 2 years (49.0% vs. 18.0%, p = 0.002), with no differences in transplant-related mortality (TRM) (2y-TRM, 19.0% and 25.0%, respectively, p = 0.588). In the analysis stratified by conditioning intensity, in patients who received MAC, those with MRD- before HSCT had better EFS (p = 0.009) and overall survival (OS) (p = 0.070) due to lower CIR (p = 0.004) than MRD+ patients. On the other hand, the survival was similar in reduced intensity conditioning (RIC) patients regardless of the MRD status.

Conclusions

Patients with MRD+ before HSCT have worse outcomes than MRD- patients. In patients who received MAC, MRD- patients have better EFS and OS due to lower CIR than MRD+ patients, probably because they represent a more chemo-sensitive group. However, among RIC patients, results were similar regardless of the MRD status.

Late Relapse after Allogeneic Stem Cell Transplantation in Patients Treated for Acute Myeloid Leukemia: Relapse Incidence, Characteristics, Role of Conditioning Regimen, and Outcome

Late relapse, beyond 2 years following alloHSCT for AML, is rare. Among the 376 patients allografted for AML in our center between 1990 and 2016, 142 (38%) relapsed. The majority (68%) of relapses occurred during the first year following transplantation. Beyond 2 years after alloHSCT, relapse was observed in 26 patients, representing 6.9% of the whole transplanted cohort and 18.3% of the relapsing patients. Cytogenetics at relapse was available in 21 patients and remained for 15 of them concordant to that at diagnosis. The majority (85.7%) of the patients were in CR prior to transplant. Thirteen patients had grade 1-2 acute GvHD, while 13 other patients had grade 3-4 acute GvHD. None of these patients subsequently developed chronic GvHD. In multivariate analyses, a predictive factor of the absence of relapse 2 years after transplantation was the development of extensive chronic GVHD. Salvage therapy achieved new CR in 77% of these patients. We conclude that late relapse can affect a significant minority of patients allografted for AML, and the intensity of the conditioning regimen does not seem to have an impact on these relapses. Moreover, we were able to show that those patients can receive effective salvage therapy.

Refractory patients with favorable/intermediate-risk acute myeloid leukemia benefit from azacytidine maintenance therapy following allogeneic hematopoietic stem cell transplantation

Recurrence following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the major cause of treatment failure in patients with myeloid malignancy. Azacytidine (AZA) maintenance is a promising therapy to prevent relapse and improve survival. We conducted a prospective, one-arm study involving 78 patients with myeloid malignancy at a high risk of recurrence who were enrolled between September 2019 and April 2022. Furthermore, 102 matched historical controls were selected using propensity score matching. With a median follow-up time of 19.6 (3.5-91.7) months, AZA maintenance therapy significantly improved relapse-free survival (RFS; log-rank test, p = 0.01). The AZA and control groups had a 1-year RFS of 87.7% (95% confidence interval [CI], 0.80-0.96) and 72.2% (95% CI, 0.64-0.82), respectively, with a hazard ratio (HR) of 0.21 (95% CI, 0.09-0. 47; p < 0.01). There were no grade 4 adverse effects or deaths related to AZA. Refractory patients with favorable/intermediate-risk acute myeloid leukemia (AML) benefited more from AZA maintenance therapy than those with adverse-risk AML according to the European Leukemia Net guidelines (RFS in favorable/intermediate-risk AML, HR = 0.29, 95% CI, 0.11-0.79; RFS in adverse-risk AML, HR = 0.57, 95% CI, 0.21-1.6; p for interaction = 0.03). Our findings suggest that AZA maintenance therapy following allo-HSCT was safe and could reduce the incidence of relapse, particularly for refractory patients with favorable/intermediate-risk AML.

Azacitidine and lenalidomide combination: a novel relapse prophylaxis regimen after allogeneic hematopoietic stem-cell transplantation in patients with acute myeloid leukemia

Introduction

While allogeneic hematopoietic stem cell transplantation (allo-HSCT) can be a curative regimen for acute myeloid leukemia (AML), relapse of AML remains a serious risk post-transplantation. Once relapsed, salvage options are limited and management of AML is difficult. Here we designed a prospective study to examine the efficacy and tolerability of maintenance therapy with azacytidine (AZA) plus low-dose lenalidomide (LEN) to prevent relapse after allo-HSCT for AML patients (ChiCTR2200061803).

Methods

AML patients post-allo-HSCT were treated with AZA (75 mg/m² for 7 days), followed by LEN (5 mg/m², day 10-28), and a 4-week resting interval, which was defined as one treatment cycle. A total of 8 cycles was recommended.

Results

37 patients were enrolled, 25 patients received at least 5 cycles, and 16 patients finished all 8 cycles. With a median follow-up time of 608 (43-1440) days, the estimated 1-year disease free survival (DFS) was 82%, cumulative incidence of relapse (CIR) was 18%, and overall survival (OS) was 100%. Three patients (8%) had grade 1-2 neutropenia without fever; one patient developed grade 3-4 thrombocytopenia and minor subdural hematoma; 4/37 patients (11%) developed chronic GVHD with a score of 1-2, without requiring systemic treatment; No patient developed acute GVHD. After AZA/LEN prophylaxis, increasing numbers of CD56⁺NK and CD8⁺ T, and decreasing of CD19⁺ B cells were observed.

Discussion

Azacitidine combined with low-dose lenalidomide was observed to be an effective relapse prophylaxis option after allo-HSCT in AML patients, and can be administered safely without significantly increasing the risk of GVHD, infection and other AEs.

Clinical Trial Registration

www.chictr.org, identifier ChiCTR2200061803.

Single-agent 5-azacytidine as post-transplant maintenance in high-risk myeloid malignancies undergoing allogeneic hematopoietic cell transplantation

Relapse is a major cause of treatment failure after allogeneic hematopoietic cell transplantation (allo-HCT) in myeloid malignancies. Additional strategies have been devised to further maximize the immunologic effect of allo-HCT, notably through maintenance therapy with hypomethylating agents such as 5-azacytidine (AZA). We conducted a single-center retrospective study to investigate the efficacy of AZA after allo-HCT for high-risk myeloid malignancies. All patients transplanted between Jan 2014 and Sept 2019 for high-risk acute myeloid leukemia (n = 123), myelodysplastic syndrome (n = 51), or chronic myelomonocytic leukemia (n = 11) were included. Patients who died, relapsed, or developed grade ≥ 2 acute graft-versus-host disease before day + 60 were excluded, as well as those who were eligible for anti-FMS-like tyrosine kinase 3 maintenance. Of the 185 included patients, 65 received AZA while 120 did not. Median age at transplant was 59 years; 51.9% of patients were males. The median follow-up was 24 months for both groups. Regarding main patient characteristics and transplantation modalities, the two groups were comparable. In multivariate analyses, there were no significant differences between the two groups in terms of 2-year cumulative incidence of relapse (HR = 1.19; 95% confidence interval (CI) 0.67-2.12; p = 0.55), overall survival (HR = 0.62; 95%CI 0.35-1.12; p = 0.12) and event-free survival (HR = 0.97; 95%CI 0.60-1.58; p = 0.91) rates. In conclusion, single-agent AZA does not appear to be an optimal drug for preventing post-transplant relapse in patients with high-risk myeloid malignancies. This study highlights the need for prospective studies of alternative therapies or combination approaches in the post-transplant setting.

Pre-Transplant Serum Leptin Levels and Relapse of Acute Myeloid Leukemia after Allogeneic Transplantation

Weight loss and metabolic activity influence outcome after allogeneic stem cell transplantation (alloSCT). This study evaluates pre-conditioning Leptin, a peptide hormone involved in metabolism and immune homeostasis, as a prognostic factor for survival, relapse and non-relapse mortality (NRM) following alloSCT. Leptin serum levels prior to conditioning were determined in a cohort of patients transplanted for various hematologic malignancies (n = 524) and correlated retrospectively with clinical outcome. Findings related to patients with acute leukemia (AL) from this sample were validated in an independent cohort. Low pre-conditioning serum Leptin was an independent prognostic marker for increased risk of relapse (but not of NRM and overall mortality) following alloSCT for AL of intermediate and advanced stage (beyond first complete remission). Multivariate analysis revealed a hazard ratio (HR) for relapse of 0.75 per log2 increase (0.59–0.96, p = 0.020). This effect was similar in an independent validation cohort. Pre-conditioning serum Leptin was validated as a prognostic marker for early relapse by fitting the multivariate Cox model to the validation data. Pre-conditioning serum Leptin levels may serve as an independent prognostic marker for relapse following alloSCT in intermediate and advanced stage AL patients. Prospective studies are required to prove whether serum Leptin could be used for guiding nutritional intervention in patients with AL undergoing alloSCT.

The Elephant in The Room: AML Relapse Post Allogeneic Hematopoietic Cell Transplantation

Relapsed acute myeloid leukemia (AML) following allogeneic hematopoietic cell transplantation (allo-HCT) is an unfavorable event associated with a poor prognosis, particularly for patients with early relapses. It usually arises from resistant leukemic blasts that escaped both preparative chemotherapy regimen and the graft-versus-leukemia (GVL) effect. Independent from the choice of salvage treatment, only minority of patients can achieve durable remissions. In recent years, better understanding of the disease relapse biology post allo-HCT allowed the application of newer strategies that could induce higher rates of remission, and potential longer survival. Those strategies aim at optimizing drugs that have a direct anti-leukemia activity by targeting different oncogenic mutations, metabolism pathways or surface antigens, and concurrently enhancing the immune microenvironment to promote GVL effect. This review discusses the current treatment landscape of AML relapse post allo-HCT.

Low-dose decitabine plus venetoclax is safe and effective as post-transplant maintenance therapy for high-risk acute myeloid leukemia and myelodysplastic syndrome

Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are usually associated with poor outcomes, especially in high-risk AML/MDS. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative option for patients suffering from high-risk AML/MDS. However, many patients relapse after allo-HSCT. Novel therapy to prevent relapse is urgently needed. Both the BCL-2 inhibitor venetoclax (VEN) and the hypomethylating agent decitabine (DEC) possess significant antitumor activity effects against AML/MDS. Administration of DEC has been shown to ameliorate graft-versus-host disease (GVHD) and boost the graft-versus-leukemia (GVL) effect post-transplantation. We therefore conducted a prospective study (ChiCTR1900025374) to examine the tolerability and efficacy of a maintenance therapy of low-dose decitabine (LDEC) plus VEN to prevent relapse after allo-HSCT for high-risk AML/MDS patients. Twenty patients with high-risk AML (n = 17) or high-risk MDS (n = 3) post-transplantation were recruited. Approximately day 100 post-transplantation, all patients received LDEC (15 mg/m2 for 3 d) followed by VEN (200 mg) on d 1-21. The cycle interval was 2 mo, and there was 10 cycles. The primary end points of this study were rates of overall survival (OS) and event-free survival (EFS). The secondary endpoints included adverse events (AEs), cumulative incidence of relapse (CIR), nonrelapse mortality (NRM), incidences of acute GVHD (aGVHD) and chronic GVHD (cGVHD), and incidences of viral infection after allo-HSCT. Survival outcomes were assessed using Kaplan-Meier analysis. The median follow-up was 598 (149-1072) d. Two patients relapsed, 1 died, and 1 is still alive after the second transplant. The 2-y OS and EFS rates were 85.2% and 84.7%, respectively. The median 2-y EFS time was 525 (149-1072) d, and 17 patients still had EFS and were alive at the time of this writing. The most common AEs were neutropenia, anemia, thrombocytopenia, neutropenic fever, and fatigue. Grade 2 or 3 AEs were observed in 35% (7/20) and 20% (4/20) of the patients, respectively. No grade >3 AEs were observed. aGVHD (any grade) and cGVHD (limited or extensive) occurred in 55% and 20% of patients, respectively. We conclude that LDEC + VEN can be administered safely after allo-HSCT with no evidence of an increased incidence of GVHD, and this combination decreases the relapse rate in high-risk AML/MDS patients. This novel maintenance therapy may be a promising way to prevent relapse in high-risk AML/MDS patients.

Increased risk of cardio-cerebrovascular disease after hematopoietic cell transplantation in patients with previous history

Background:

The impacts of previous cardio-cerebrovascular disease (pre-CCVD) on the outcomes of hematopoietic cell transplantation (HCT) are not well described. Patients with pre-CCVD may often be poor candidates for HCT. This study aimed to investigate the impact of pre-CCVD on transplant outcomes.

Methods:

A retrospective study was conducted between patients with and without pre-CCVD who consecutively received allogeneic or autologous HCT between November 2013 and January 2020 with a matching of age and disease status. The cardiovascular complications and HCT outcomes of the two groups were evaluated and compared. The primary endpoints were post-transplant cardio-cerebrovascular disease (post-CCVD) and non-relapse mortality (NRM). We used a multivariable Cox proportional hazard model and the Fine-Gray competing risk regressions for analyses to estimate the hazard ratios (HRs).

Results:

The outcomes of 23 HCT recipients with pre-CCVD were compared with those of 107 patients in the control group. No significant differences were noted in terms of engraftment, overall survival (OS) (67.00% vs. 67.90%, P = 0.983), or relapse (29.78% vs. 28.26%, P = 0.561) between the pre-CCVD group and the control group. The cumulative incidences of 2-year NRM were similar between patients with pre-CCVD and the controls (14.68% vs. 17.08%, P = 0.670). However, pre-CCVD was associated with an increased incidence of post-CCVD (HR: 12.50, 95% confidence interval [CI]: 3.88–40.30, P < 0.001), which was an independent risk factor for increased NRM (HR: 10.29, 95% CI: 3.84–27.62, P < 0.001) and inferior OS (HR: 10.29, 95% CI: 3.84–27.62, P < 0.001).

Conclusions:

These findings suggest that the existence of pre-CCVD before transplantation might not result in increased mortality directly but superpose the toxicity of the transplantation procedure, leading to a risk of post-CCVD. Post-CCVD was a powerful predictor for high NRM and inferior OS. Further risk stratification of pre-CCVD is needed to reduce NRM in various transplantation settings.

Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia: Who, When, and How?

Although the majority of patients with acute myeloid leukemia (AML) treated with intensive chemotherapy achieve a complete remission (CR), many are destined to relapse if treated with intensive chemotherapy alone. Allogeneic stem cell transplant (allo-SCT) represents a pivotally important treatment strategy in fit adults with AML because of its augmented anti-leukemic activity consequent upon dose intensification and the genesis of a potent graft-versus-leukemia effect. Increased donor availability coupled with the advent of reduced intensity conditioning (RIC) regimens has dramatically increased transplant access and consequently allo-SCT is now a key component of the treatment algorithm in both patients with AML in first CR (CR1) and advanced disease. Although transplant related mortality has fallen steadily over recent decades there has been no real progress in reducing the risk of disease relapse which remains the major cause of transplant failure and represents a major area of unmet need. A number of therapeutic approaches with the potential to reduce disease relapse, including advances in induction chemotherapy, the development of novel conditioning regimens and the emergence of the concept of post-transplant maintenance, are currently under development. Furthermore, the use of genetics and measurable residual disease technology in disease assessment has improved the identification of patients who are likely to benefit from an allo-SCT which now represents an increasingly personalized therapy. Future progress in optimizing transplant outcome will be dependent on the successful delivery by the international transplant community of randomized prospective clinical trials which permit examination of current and future transplant therapies with the same degree of rigor as is routinely adopted for non-transplant therapies.

How I treat measurable (minimal) residual disease in acute leukemia after allogeneic hematopoietic cell transplantation

Although allogeneic hematopoietic cell transplantation (allo-HCT) is currently the standard curative treatment of acute leukemia, relapse remains unacceptably high. Measurable (minimal) residual disease (MRD) after allo-HCT may be used as a predictor of impending relapse and should be part of routine follow-up for transplanted patients. Patients with MRD may respond to therapies aiming to unleash or enhance the graft-versus-leukemia effect. However, evidence-based recommendations on how to best implement MRD testing and MRD-directed therapy after allo-HCT are lacking. Here, I describe our institutional approach to MRD monitoring for preemptive MRD-triggered intervention, using patient scenarios to illustrate the discussion.

The incidence and prognostic effect of Fms-like tyrosine kinase 3 gene internal tandem and nucleolar phosphoprotein 1 genes in acute myeloid leukaemia: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Molecular genotyping is an important prognostic role in acute myeloid leukemia (AML) patients. We aimed to design this meta-analysis to discuss the incidence and prognostic effect of nucleolar phosphoprotein 1 (NPM1) and Fms-like tyrosine kinase 3 gene internal tandem (FLT3-ITD) gene in AML patients.

METHODS

PubMed, Embase, Medline, and Cochrane library were systematically searched due to May 15, 2020. Four combinations of genotypes (FLT3-ITDneg/NPM1mut, FLT3-ITDpos/NPM1mut, FLT3-ITDneg/NPM1wt, FLT3-ITDpos/NPM1wt) were compared in association with the overall survival (OS) and leukemia-free survival (LFS) outcome, which expressed as pooled hazard ratio (HR) and 95% confidence intervals (CIs).

RESULTS

Twenty-eight studies were included in our study. The incidence of FLT3-ITDneg/NPM1mut, FLT3-ITDpos/NPM1mut, FLT3-ITDneg/NPM1wt, and FLT3-ITDpos/NPM1wt was 16%, 13%, 50%, and 10%, respectively. The patients with FLT3-ITDneg/NPM1mut gene may have the best OS and LFS when comparing with FLT3-ITDpos/NPM1mut (HR = 1.94 and 1.70, P < .01), FLT3-ITDneg/NPM1wt (HR = 1.57 and 2.09, P < .01), and FLT3-ITDpos/NPM1wt (HR = 2.25 and 2.84, P < .001).

CONCLUSION

AML patients with FLT3-ITDneg/NPM1mut gene type have the best survival outcome than the other 3 gene types, which should be an independent genotyping in AML classification.

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 MRD^neg, 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.

Update on management and progress of novel therapeutics for R/R AML: an Iberian expert panel consensus

A significant proportion of adult patients with acute myeloid leukemia (AML) fail to achieve complete remission or will relapse later on after achieving it. Prognosis for relapsed or refractory (R/R) AML patients remains discouraging, with the main curative option still relying on hematopoietic stem cell transplant (HSCT) for those who are eligible. Beyond morphological bone marrow and peripheral blood assessment, evaluation of patient performance status and comorbidities, as well as genetic/molecular characterization, is crucial to make an accurate diagnosis and prognosis, which will be useful to select the most appropriate treatment. Emerging strategies are mainly focusing on the development of immune- and molecular-based approaches. Novel targeted therapies are generally well tolerated, potentially allowing them to be administered alone or in combination with classical chemotherapy agents. Enrolment in clinical trials should be considered first option for R/R AML patients, either as a bridge to HSCT or to benefit from novel therapies that eventually may prolong survival and improve quality of life. An Iberian expert panel has reviewed the recent advances in the management of R/R AML with the aim to develop updated evidence and expert opinion-based recommendations.

What is the role of a second allogeneic hematopoietic cell transplant in relapsed acute myeloid leukemia?

Relapsed acute myeloid leukemia (AML) after an allogeneic hematopoietic cell transplant (allo-HCT) entails a poor prognosis. Treating these cases is challenging due to lack of effective therapies and, in some cases, poor performance status and/or presence of graft-versus-host disease (GVHD), among others. No randomized controlled trial (RCT) has ever been conducted comparing a second allo-HCT against other treatments. Existing data are mainly from observational studies or registries. Success of a second allo-HCT is dependent on appropriately selecting patients who might achieve best outcomes with reasonable non-relapse mortality (NRM) risk. Several factors are associated with worse outcomes, namely a shorter time from first allo-HCT to relapse or to the second allo-HCT, and AML not being in complete hematologic remission (CR). Patients relapsing earlier than 6 months or having active/persistent disease should be enrolled in clinical trials. Limitations of the published literature include retrospective small size studies, a heterogeneous population, and absence of information on somatic mutations, among others. Future studies assessing the role of a second allo-HCT should evaluate the impact of IDH1, IDH2, or others on outcomes; and the feasibility and efficacy of targeted therapies in the pre-, peri-, or post-second allo-HCT setting.

Combination Lenalidomide and Azacitidine: A Novel Salvage Therapy in Patients Who Relapse After Allogeneic Stem-Cell Transplantation for Acute Myeloid Leukemia

PURPOSE

Salvage options for patients who relapse after allogeneic stem-cell transplantation (allo-SCT) for acute myeloid leukemia (AML) and myelodysplasia (MDS) remain limited, and novel treatment strategies are required. Both lenalidomide (LEN) and azacitidine (AZA) possess significant antitumor activity effect in AML. Administration of LEN post-transplantation is associated with excessive rates of graft-versus-host disease (GVHD), but AZA has been shown to ameliorate GVHD in murine transplantation models. We therefore examined the tolerability and activity of combined LEN/AZA administration in post-transplantation relapse.

PATIENTS AND METHODS

Twenty-nine patients who had relapsed after allo-SCT for AML (n = 24) or MDS (n = 5) were treated with sequential AZA (75 mg/m2 for 7 days) followed by escalating doses of LEN on days 10 to 30. Dose allocation and maximum tolerated dose (MTD) estimation were guided by a modified Bayesian continuous reassessment method (CRM).

RESULTS

Sequential AZA and LEN therapy was well tolerated. The MTD of post-transplantation LEN, in combination with AZA, was determined as 25 mg daily. Three patients developed grade 2 to 4 GVHD. There was no GVHD-related mortality. Seven of 15 (47%) patients achieved a major clinical response after LEN/AZA therapy. CD8+ T cells demonstrated impaired interferon-γ/tumor necrosis factor-α production at relapse, which was not reversed during LEN/AZA administration.

CONCLUSION

We conclude LEN can be administered safely post-allograft in conjunction with AZA, and this combination demonstrates clinical activity in relapsed AML/MDS without reversing biologic features of T-cell exhaustion. The use of a CRM model delivered improved efficiency in MTD assessment and provided additional flexibility. Combined LEN/AZA therapy represents a novel and active salvage therapy in patients who had relapsed post-allograft.