A US Multicenter Collaborative Study on Outcomes of Hematopoietic Cell Transplantation in Hepatosplenic T-Cell Lymphoma

Hepatosplenic T-cell lymphoma (HSTCL) is a rare and aggressive type of peripheral T-cell lymphoma with median overall survival (OS) of approximately 1 year. Data on the effectiveness of hematopoietic cell transplantation (HCT) is limited, as is the choice between autologous HCT (auto-HCT) and allogeneic HCT (allo-HCT) in the treatment of this disease. To evaluate the outcome of patients with HSTCL who underwent either auto-HCT or allo-HCT, we performed a multi-institutional retrospective cohort study to assess outcomes of HCT in HSTCL patients. Fifty-three patients with HSTCL were included in the study. Thirty-six patients received an allo-HCT and 17 received an auto-HCT. Thirty-five (66%) were males. Median age at diagnosis was 38 (range 2 to 64) years. Median follow-up for survivors was 75 months (range 8 to 204). The median number of prior lines of therapy was 1 (range 1 to 4). Median OS and progression-free survival (PFS) for the entire cohort were 78.5 months (95% CI: 25 to 79) and 54 months (95% CI: 18 to 75), respectively. There were no significant differences in OS (HR: 0.63, 95% CI: 0.28 to 1.45, P = .245) or PFS (HR: 0.7, 95% CI: 0.32 to 1.57, P = .365) between the allo-HCT and auto-HCT groups, respectively. In the allo-HCT group, the 3-year cumulative incidence of relapse was 35% (95% CI: 21 to 57), while 3-year cumulative incidence of NRM was 16% (95% CI: 7 to 35). In the auto-HCT group, the 3-year cumulative incidence of relapse and NRM were 43% (95% CI: 23 to 78) and 14% (95% CI: 4 to 52), respectively. Both Auto-HCT and Allo-HCT are effective consolidative strategies in patients with HSTCL, and patients should be promptly referred for HCT evaluation.

Defining and Grading Infections in Clinical Trials Involving Hematopoietic Cell Transplantation: A Report From the BMT CTN Infectious Disease Technical Committee

The Blood and Marrow Transplant Clinical Trials Network (BMT-CTN) was established in 2001 to conduct large multi-institutional clinical trials addressing important issues towards improving the outcomes of HCT and other cellular therapies. Trials conducted by the network investigating new advances in HCT and cellular therapy not only assess efficacy but require careful capturing and severity assessment of adverse events and toxicities. Adverse infectious events in cancer clinical trials are typically graded according to the National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE). However, there are limitations to this framework as it relates to HCT given the associated immunodeficiency and delayed immune reconstitution. The BMT-CTN Infection Grading System is a monitoring tool developed by the BMT CTN to capture and monitor infectious complications and differs from the CTCAE by its classification of infections based on their potential impact on morbidity and mortality for HCT recipients. Here we offer a report from the BMT CTN Infectious Disease Technical Committee regarding the rationale, development, and revising of BMT-CTN Infection Grading System and future directions as it applies to future clinical trials involving HCT and cellular therapy recipients.

Incorporating radiation with anti-CD19 chimeric antigen receptor T-cell therapy for relapsed/refractory non-Hodgkin lymphoma: A multicenter consensus approach

Anti-CD19 chimeric antigen receptor T-cell therapy (CART) has revolutionized the outcomes of relapsed and/or refractory B-cell non-Hodgkin lymphoma. However, CART is still limited by its availability, toxicity, and response durability. Not all patients make it to the CART infusion phase due to disease progression. Among those who receive CART, a significant number of patients experience life-threatening cytokine release syndrome toxicity, and less than half maintain a durable response with the majority relapsing in pre-existing sites of disease present pre-CART. Radiation therapy stands as a promising peri-CART and salvage treatment that can improve the outcomes of these patients. Evidence suggests that bridging radiotherapy prior to CART controls the disease during the manufacturing period, augments response rates and local control, cytoreduces/debulks the disease and decreases the severity of cytokine release syndrome, and may prolong disease-free intervals and survival especially in patients with bulky disease. Consolidative radiotherapy for residual post-CART disease alters the pattern of relapse and improves local recurrence-free and progression-free survivals. Salvage radiotherapy for relapsed post-CART disease has favorable survival outcomes when delivered comprehensively for patients with limited relapsed disease and palliates symptoms for patients with diffuse relapsed disease. The biology of the disease during the peri-CART period is poorly understood, and further studies investigating the optimal timing and dosing of radiation therapy (RT) are needed. In this review, we tackle the most significant challenges of CART, review and propose how RT can help mitigate these challenges, and provide The Mayo Clinic experts' approach on incorporating RT with CART.

Translational development of a novel BAFF-R CAR-T therapy targeting B-cell lymphoid malignancies

Several CD19-targeting CAR-T cells are used to treat leukemias and lymphomas; however, relapsed and/or refractory (R/R) disease is still observed in a significant number of patients. Additionally, the success of CD19-CAR-T cell therapies is not uniform across hematological malignancies, particularly in chronic lymphocytic leukemia (CLL). In this study, we present the development of a novel CAR-T cell therapy targeting B-cell activating factor receptor (BAFF-R), a key regulator of B-cell proliferation and maturation. A new monoclonal antibody against BAFF-R was generated from a hybridoma clone and used to create a novel MC10029 CAR construct. Through a series of in vitro and in vivo models using the Nalm-6 cell line for leukemia and the Z138 cell line for lymphoma, we demonstrated the antigen-specific cytotoxicity of MC10029 CAR-T cells against tumor cells. Additionally, MC10029 CAR-T cells exhibited potent antitumor effects against CD19 knockout tumor cells, mimicking CD19-negative R/R disease. MC10029 CAR-T cells were specifically targeted to CLL, in which BAFF-R is nearly always expressed. The cytotoxicity of MC10029 CAR-T cells was first shown in the MEC-1 CLL cell line, before we turned our efforts to subject-derived samples. Using healthy donor-engineered MC10029 CAR-T cells against enriched primary tumor cells, followed by subject-derived MC10029 CAR-T cells against autologous tumor cells, we showed the efficacy of MC10029 CAR-T cells against CLL subject samples. With these robust data, we have advanced to the production of MC10029 CAR-T cells, using GMP lentivirus, and obtained an IND approval in preparation for a Phase 1 clinical trial.

Allogeneic hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: a CIBMTR analysis

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with a poor prognosis and considered incurable with conventional chemotherapy. Small observational studies reported allogeneic hematopoietic cell transplantation (allo-HCT) offers durable remissions in patients with BPDCN. We report an analysis of patients with BPDCN who received an allo-HCT, using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). We identified 164 patients with BPDCN from 78 centers who underwent allo-HCT between 2007 and 2018. The 5-year overall survival (OS), disease-free survival (DFS), relapse, and nonrelapse mortality (NRM) rates were 51.2% (95% confidence interval [CI], 42.5-59.8), 44.4% (95% CI, 36.2-52.8), 32.2% (95% CI, 24.7-40.3), and 23.3% (95% CI, 16.9-30.4), respectively. Disease relapse was the most common cause of death. On multivariate analyses, age of ≥60 years was predictive for inferior OS (hazard ratio [HR], 2.16; 95% CI, 1.35-3.46; P = .001), and higher NRM (HR, 2.19; 95% CI, 1.13-4.22; P = .02). Remission status at time of allo-HCT (CR2/primary induction failure/relapse vs CR1) was predictive of inferior OS (HR, 1.87; 95% CI, 1.14-3.06; P = .01) and DFS (HR, 1.75; 95% CI, 1.11-2.76; P = .02). Use of myeloablative conditioning with total body irradiation (MAC-TBI) was predictive of improved DFS and reduced relapse risk. Allo-HCT is effective in providing durable remissions and long-term survival in BPDCN. Younger age and allo-HCT in CR1 predicted for improved survival, whereas MAC-TBI predicted for less relapse and improved DFS. Novel strategies incorporating allo-HCT are needed to further improve outcomes.

Consolidative radiotherapy for residual fluorodeoxyglucose activity on day +30 post CAR T-cell therapy in non-Hodgkin lymphoma

Majority of non-Hodgkin lymphoma (NHL) patients who achieve partial response (PR) or stable disease (SD) to CAR T-cell therapy (CAR T) on day +30 progress and only 30% achieve spontaneous complete response (CR). This study is the first to evaluate the role of consolidative radiotherapy (cRT) for residual fluorodeoxyglucose (FDG) activity on day +30 post- CAR T in NHL. We retrospectively reviewed 61 patients with NHL who received CAR T and achieved PR or SD on day +30. Progression-free survival (PFS), overall survival (OS), and local relapse-free survival (LRFS) were assessed from CAR T infusion. cRT was defined as comprehensive - treated all FDG-avid sites - or focal. Following day +30 positron emission tomography scan, 45 patients were observed and 16 received cRT. Fifteen (33%) observed patients achieved spontaneous CR, and 27 (60%) progressed with all relapses involving initial sites of residual FDG activity. Ten (63%) cRT patients achieved CR, and four (25%) progressed with no relapses in the irradiated sites. The 2-year LRFS was 100% in the cRT sites and 31% in the observed sites (P<0.001). The 2-year PFS was 73% and 37% (P=0.025) and the 2-year OS was 78% and 43% (P=0.12) in the cRT and observation groups, respectively. Patients receiving comprehensive cRT (n=13) had superior 2- year PFS (83% vs. 37%; P=0.008) and 2-year OS (86% vs. 43%; P=0.047) compared to observed or focal cRT patients (n=48). NHL patients with residual FDG activity following CAR T are at high risk of local progression. cRT for residual FDG activity on day +30 post-CAR T appears to alter the pattern of relapse and improve LRFS and PFS.

Trends in utilization of stored cryopreserved autologous peripheral hematopoietic cells intended for a second (or beyond) autologous hematopoietic cell transplantation in patients with multiple myeloma: a single center experience

Due to the advent of effective novel therapies for multiple myeloma (MM), the use of cryopreserved autologous peripheral blood hematopoietic cells (APBHC) for a salvage autologous transplant (auto-HCT) is in decline. We evaluated utilization trends and costs associated with cryopreserved APBHC in patients with MM. We retrospectively evaluated the clinicopathologic data from 440 patients with MM who underwent APBHC mobilization and collection at Mayo Clinic Florida between 2010 and 2019. Based on institution-specific charges as of May 2021, the cost of 1 session of APBHC collection/apheresis was $4,680 and the cost of 1 year of APBHC cryopreservation was $4,790 per patient. Out of 347 patients who had APBHC in cryopreservation, 5 (1.4%) underwent a salvage auto-HCT and 61% of patients had ≥1 excess collection sessions for APBHC that ultimately went unused. The median cost of excess collection sessions was $4,680 per patient (range, $4,680-$32,760) and the median total cost for excess collection sessions plus costs for storage was $23,840 per patient (range, $4,680-$85,450). The sum of costs of excess collection sessions was $2,077,920 and the sum of costs of cryopreservation was $5,812,665. Institutional policies regarding universal APBHC collection and long-term storage should be reevaluated in the era of novel therapeutics.

Consolidative Radiotherapy for Residual PET-Avid Disease on Day +30 Post CAR T-Cell Therapy in Non-Hodgkin Lymphoma

PURPOSE/OBJECTIVE(S)

Up to30% of non-Hodgkin lymphoma (NHL) patients achieve a partial response (PR) to anti-CD19 Chimeric Antigen Receptor T-cell Therapy (CART) on day +30. Most PR patients relapse and only 30% achieve spontaneous complete response (CR) without additional therapies. This study is the first to report on the role of consolidative radiotherapy (cRT) for PR PET-avid disease on day +30 post-CART in NHL.

MATERIALS/METHODS

Aretrospective review across 3 institutions from 2018 to 2022 identified 60 patients with B-cell NHL who received CART and achieved PR (Deauville 4-5) with <5 PET-avid disease sites on day +30. Progression-free survival (PFS) was defined from CART infusion to any disease progression. Overall survival (OS) was defined from CART infusion to death. Local relapse-free survival (LRFS), calculated based on the total number of PR sites, was defined from CART infusion to local relapse (LR) in the PR site identified on day +30. cRT was defined as comprehensive (compRT) - treated all PR PET-avid sites - or focal (focRT).

RESULTS

Followingday +30 PET scan, 45 PR patients were observed and 15 received cRT. Only one patient received consolidative systemic therapy and belonged to the cRT group. Prior to CART, bridging RT was given to 13 patients (9 in observation group and 4 in cRT group). There were no significant differences in the pre-CART and day +30 baseline characteristics, including the median size and SUVmax of the PR sites, between the two groups. However, the median number of PR sites on day +30 was higher in the cRT group (2 [range 1-3] vs 1 [range 1-3], p = 0.003). The median equivalent 2 Gy dose was 39.1 (Interquartile range 36.8-41) Gy, and the most common cRT regimen was 37.5 Gy in 15 fractions. The median follow-up was 21 months. Among the observed patients, 15 (33%) achieved spontaneous CR, and 27 (60%) experienced disease progression with all relapses involving the initial PR sites. Among patients who received cRT, 10 (67%) achieved CR, and 3 (20%) had disease progression with no relapses in the radiated PR sites. None of the 10 cRT patients achieving CR relapsed or required subsequent therapies. The 2-year PFS was 80% and 37% (p = 0.012) and the 2-year OS was 78% and 43% (p = 0.12) in the cRT and observation groups, respectively. Patients consolidated with compRT (n = 12) had superior 2-year PFS (92% vs 37%, p = 0.003) and 2-year OS (86% vs 43%, p = 0.048) compared to observed or focRT patients (n = 48). There were no grade 3+ RT-related toxicities. A total of 90 PR sites were identified; 64 were observed and 26 received cRT. Fourteen (22%) observed PR sites achieved spontaneous sustained CR and 42 (66%) experienced LR. Twenty-four (92%) PR sites consolidated with cRT achieved sustained CR and none experienced LR. The 2-year LRFS was 100% in the cRT sites and 31% in the observed sites (p<0.001).

CONCLUSION

NHL patients who achieve PR by PET to CART are at high risk of local progression. cRT for residual PET-avid disease on day +30 post-CART appears to alter the pattern of relapse and improve LRFS and PFS.

Real-world experience with ponatinib therapy in chronic phase chronic myeloid leukemia: impact of depth of response on survival and prior exposure to nilotinib on arterial occlusive events

We surveyed the performance of ponatinib, as salvage therapy, in a real-world setting of chronic phase chronic myeloid leukemia (CML-CP). Among 55 consecutive patients (median age 49 years) with relapsed/refractory CML-CP, 35 (64%) had failed ≥3 tyrosine kinase inhibitors (TKIs), 35 (64%) were pre-treated with nilotinib, and 14 (28%) harbored ABL1T315I. At start of ponatinib (median dose 30 mg/day), 40 patients were already in complete hematologic (CHR), 4 in complete cytogenetic (CCyR), 3 in major molecular (MMR) remission, while 8 had not achieved CHR (NR). Ponatinib improved the depth of response in 13 (33%), 3 (75%), 2 (66%), and 4 (50%) patients with CHR, CCyR, MMR, and NR, respectively (p = 0.02). At a median follow-up of 42 months, 13 (23%) deaths, 5 (9%) blast transformations, and 25 (45%) allogeneic transplants were recorded. Five/10-year post-ponatinib survival was 77%/58% with no significant difference when patients were stratified by allogeneic transplant (p = 0.94), ponatinib-induced deeper response (p = 0.28), or a post-ponatinib ≥CCyR vs CHR remission state (p = 0.25). ABL1T315I was detrimental to survival (p = 0.04) but did not appear to affect response. Prior exposure to nilotinib was associated with higher risk of arterial occlusive events (AOEs; 11% vs 0%; age-adjusted p = 0.04). Ponatinib starting/maintenance dose (45 vs 15 mg/day) did not influence either treatment response or AOEs. Our observations support the use of a lower starting/maintenance dose for ponatinib in relapsed/refractory CML-CP but a survival advantage for deeper responses was not apparent and treatment might not overcome the detrimental impact of ABL1T315I on survival. The association between prior exposure to nilotinib and a higher risk of post-ponatinib AOEs requires further validation.

Impact of bortezomib-based versus lenalidomide maintenance therapy on outcomes of patients with high-risk multiple myeloma

BACKGROUND

Lenalidomide maintenance after autologous stem cell transplant (ASCT) in multiple myeloma (MM) results in superior progression-free survival and overall survival. However, patients with high-risk multiple myeloma (HRMM) do not derive the same survival benefit from lenalidomide maintenance compared with standard-risk patients. The authors sought to determine the outcomes of bortezomib-based maintenance compared with lenalidomide maintenance in patients with HRMM undergoing ASCT.

METHODS

In total, the authors identified 503 patients with HRMM who were undergoing ASCT within 12 months of diagnosis from January 2013 to December 2018 after receiving triplet novel-agent induction in the Center for International Blood and Marrow Transplant Research database. HRMM was defined as deletion 17p, t(14;16), t(4;14), t(14;20), or chromosome 1q gain.

RESULTS

Three hundred fifty-seven patients (67%) received lenalidomide alone, and 146 (33%) received bortezomib-based maintenance (with bortezomib alone in 58%). Patients in the bortezomib-based maintenance group were more likely to harbor two or more high-risk abnormalities and International Staging System stage III disease (30% vs. 22%; p = .01) compared with the lenalidomide group (24% vs. 15%; p < .01). Patients who were receiving lenalidomide maintenance had superior progression-free survival at 2 years compared with those who were receiving either bortezomib monotherapy or combination therapy (75% vs. 63%; p = .009). Overall survival at 2 years was also superior in the lenalidomide group (93% vs. 84%; p = .001).

CONCLUSIONS

No superior outcomes were observed in patients with HRMM who received bortezomib monotherapy or (to a lesser extent) in those who received bortezomib in combination as maintenance compared with lenalidomide alone. Until prospective data from randomized clinical trials are available, post-transplant therapy should be tailored to each patient with consideration for treating patients in clinical trials that target novel therapeutic strategies for HRMM, and lenalidomide should remain a cornerstone of treatment.

Association between the choice of the conditioning regimen and outcomes of allogeneic hematopoietic cell transplantation for myelofibrosis

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only curative treatment for myelofibrosis. However, the optimal conditioning regimen either with reduced-intensity conditioning (RIC) or myeloablative conditioning (MAC) is not well known. Using the Center for International Blood and Marrow Transplant Research database, we identified adults aged ≥18 years with myelofibrosis undergoing allo-HCT between 2008-2019 and analyzed the outcomes separately in the RIC and MAC cohorts based on the conditioning regimens used. Among 872 eligible patients, 493 underwent allo-HCT using RIC (fludarabine/ busulfan n=166, fludarabine/melphalan n=327) and 379 using MAC (fludarabine/busulfan n=247, busulfan/cyclophosphamide n=132). In multivariable analysis with RIC, fludarabine/melphalan was associated with inferior overall survival (hazard ratio [HR]=1.80; 95% confidenec interval [CI]: 1.15-2.81; P=0.009), higher early non-relapse mortality (HR=1.81; 95% CI: 1.12-2.91; P=0.01) and higher acute graft-versus-host disease (GvHD) (grade 2-4 HR=1.45; 95% CI: 1.03-2.03; P=0.03; grade 3-4 HR=2.21; 95%CI: 1.28-3.83; P=0.004) compared to fludarabine/busulfan. In the MAC setting, busulfan/cyclophosphamide was associated with a higher acute GvHD (grade 2-4 HR=2.33; 95% CI: 1.67-3.25; P<0.001; grade 3-4 HR=2.31; 95% CI: 1.52-3.52; P<0.001) and inferior GvHD-free relapse-free survival (GRFS) (HR=1.94; 95% CI: 1.49-2.53; P<0.001) as compared to fludarabine/busulfan. Hence, our study suggests that fludarabine/busulfan is associated with better outcomes in RIC (better overall survival, lower early non-relapse mortality, lower acute GvHD) and MAC (lower acute GvHD and better GRFS) in myelofibrosis.

Impact of second primary malignancy post-autologous transplantation on outcomes of multiple myeloma: a CIBMTR analysis

The overall survival (OS) has improved significantly in multiple myeloma (MM) over the last decade with the use of proteasome inhibitor and immunomodulatory drug-based combinations, followed by high-dose melphalan and autologous hematopoietic stem cell transplantation (auto-HSCT) and subsequent maintenance therapies in eligible newly diagnosed patients. However, clinical trials using auto-HSCT followed by lenalidomide maintenance have shown an increased risk of second primary malignancies (SPM), including second hematological malignancies (SHM). We evaluated the impact of SPM and SHM on progression-free survival (PFS) and OS in patients with MM after auto-HSCT using CIBMTR registry data. Adult patients with MM who underwent first auto-HSCT in the United States with melphalan conditioning regimen from 2011 to 2018 and received maintenance therapy were included (n = 3948). At a median follow-up of 37 months, 175 (4%) patients developed SPM, including 112 (64%) solid, 36 (20%) myeloid, 24 (14%) SHM, not otherwise specified, and 3 (2%) lymphoid malignancies. Multivariate analysis demonstrated that SPM and SHM were associated with an inferior PFS (hazard ratio [HR] 2.62, P < .001 and HR 5.01, P < .001, respectively) and OS (HR 3.85, P < .001 and HR 8.13, P < .001, respectively). In patients who developed SPM and SHM, MM remained the most frequent primary cause of death (42% vs 30% and 53% vs 18%, respectively). We conclude the development of SPM and SHM leads to a poor survival in patients with MM and is an important survivorship challenge. Given the median survival for MM continues to improve, continued vigilance is needed to assess the risks of SPM and SHM with maintenance therapy post-auto-HSCT.

Response to COVID-19 vaccination post CAR T therapy in patients with non-Hodgkin lymphoma and multiple myeloma

COVID-19 adversely affects individuals with cancer. Several studies have found that seroconversion rates among patients with hematologic malignancies are suboptimal when compared to patients without cancer. Patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) are immunocompromised due to impaired humoral and cellular immunity in addition to prescribed immunosuppressive therapy. Chimeric antigen receptor T-cell (CAR T) therapy is now widely used for NHL and MM, but little is known about seroconversion rates after COVID-19 vaccination among these populations. We evaluated SARS-CoV-2 spike-binding IgG antibody levels following COVID-19 vaccination among NHL and MM CAR T therapy recipients. Out of 104 CAR T infusions, 19 patients developed known COVID-19 infection post-CAR T. We tested 17 patients that received CAR T for antibody spike titers post COVID-19 vaccination, only 29 % (n = 5) were able to mount a clinically relevant antibody response (>250 IU/mL).

Don't Put the CART Before the Horse: The Role of Radiation Therapy in Peri-CAR T-cell Therapy for Aggressive B-cell Non-Hodgkin Lymphoma

PURPOSE

The optimal approach to incorporate radiation therapy (RT) in conjunction with chimeric antigen receptor (CAR) T-cell therapy (CART) for relapsed/refractory (r/r) B-cell non-Hodgkin lymphoma (bNHL) remains unclear. This study documented the RT local control rate among patients who received bridging radiation therapy (BRT) before CART and compares it with those who received salvage radiation therapy (SRT) after CART. This article further reports on a promising way to use SRT for post-CART disease and identifies predictors for RT in-field recurrence.

METHODS AND MATERIALS

We retrospectively reviewed 83 patients with r/r bNHL who received CART and RT, either as BRT pre-CART infusion (n = 35) or as SRT post-CART infusion (n = 48), between 2018 and 2021. RT was defined as comprehensive (compRT; ie, treated all sites of active disease) or focal (focRT). Limited disease was defined as disease amenable to compRT, involving <5 active disease sites.

RESULTS

At time of RT, patients who received BRT before CART had bulkier disease sites (median diameter, 8.7 vs 5.5 cm; P = .01) and were treated to significantly lower doses (median equivalent 2-Gy dose, 23.3 vs 34.5 Gy; P = .002), compared with SRT post-CART. Among 124 total irradiated sites identified, 8 of 59 (13%) bridged sites and 21 of 65 (32%) salvaged sites experienced in-field recurrence, translating to 1-year local control rates (LC) of 84% and 62%, respectively (P = .009). Patients with limited post-CART disease (n = 37) who received compSRT (n = 26) had better overall survival (51% vs 12%; P = .028), freedom from subsequent progression (31% vs 0%; P < .001), and freedom from subsequent event (19% vs 0%; P = .011) compared with patients with limited disease who received focSRT (n = 11).

CONCLUSIONS

BRT followed by CART appears to be associated with improved LC compared with SRT in r/r bNHL. Nonetheless, SRT offers a promising salvage intervention for limited (<5 sites) relapsed post-CART disease if given comprehensively.

The Impact of Pre-Apheresis Health Related Quality of Life on Peripheral Blood Progenitor Cell Yield and Donor's Health and Outcome: Secondary Analysis of Patient-Reported Outcome Data from the RDSafe and BMT CTN 0201 Clinical Trials

There is a lack of evidence about how health-related quality of life (HRQoL), including psychosocial factors, might affect donation-related experiences and clinical markers in the context of hematopoietic stem cell donation. The broader literature suggests that psychological factors, including anxiety and depression, are associated with higher levels of inflammatory burden leading to poorer postprocedural outcomes including longer hospital stays and increased pain perception. In this study, we aimed to evaluate whether predonation HRQoL markers predict toxicity profile and stem cell yield after peripheral blood stem cell (PBSC) donation in healthy donors. The study population comprised adult granulocyte colony-stimulating factor mobilized PBSC-related donors (RD) (n = 157) and unrelated donors (URD) (n = 179) enrolled in the related donor safety study (RDSafe) and Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 0201 clinical trials. Pre-donation HRQoL was assessed using the Short-Form-12 (SF-12) in RDSafe and SF-8 questionnaire in BMT CTN 0201 (higher score is better). The aims of this study were to (a) determine the impact of pre-donation HRQoL on peri-collection pain and acute toxicities experienced and (b) to investigate the pre-procedural HRQoL indicators on stem cells yield. URDs were younger than RDs (median age 35 versus 63). A higher proportion of RDs were female (50% versus 40%) and obese (41% versus 35%). A higher proportion of RD PBSC donations required 2 days or more of apheresis (44% versus 21%). More RD collections were lower volume procedures (<18L, 16% versus 28%), and required a central line (28% versus 11%). RDs were more likely to report pre-donation grade 1-2 pain (27% versus 8%) and other toxicities (16% versus 6%). Among RDs, a lower pre-donation physical component summary (PCS) score was associated with significantly more grade 2-4 pain at 1 month (P = .004) and at 1-year after donation (P = .0099) in univariable analyses. In multivariable analysis, pre-donation PCS remained significantly associated with grade 2-4 pain 1 month after donation (P = .0098). More specifically, RDs with predonation PCS scores in the highest quartile were less likely to report pain compared with donors with PCS scores in the lowest quartile (odds ratio 0.1; 95% confidence interval 0.01-0.83; P = .005). There was also a trend toward higher grade 2-4 pain at 1-year post-donation among RDs with lower predonation PCS score (P = .018). Among URDs, neither PCS nor mental component summary (MCS) scores were associated with pain or toxicities at any time point after donation based on the univariable analysis. Because of low rates of postdonation grade 2-4 pain and toxicities, multivariable analysis was not performed in the URD setting. Moreover, there was no correlation between preapheresis HRQoL score (PCS or MCS) and PBSC collection yield in either the RD or URD setting. Our study demonstrates that pre-donation HRQoL scores are significantly associated with the toxicity profile after PBSC donation in the RD setting, with adult RDs with lower predonation physical HRQoL experiencing higher levels of pain at 1 month and persisting up to 12 months after a PBSC collection procedure. There were no such associations found in URD. Our findings can help clinicians identify donors at higher risk of pain with donation, and lead to personalized information and interventions for specific donors. Lack of correlation between predonation HRQoL and stem cell yield may be due to a small sample size and warrants further evaluation.

In-field recurrences in relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) bridged with radiation prior to CD19 chimeric antigen receptor T-cell therapy (CART)

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Background: The majority of R/R NHL progressions after CART involve pre-existing sites, suggesting a promising role for bridging radiotherapy (bRT). We assessed the local control rate of disease sites bridged with radiotherapy prior to CART and identified predictors of in-field recurrence. Methods: We retrospectively reviewed 35 patients with aggressive B-cell NHL who received bRT between leukapheresis and CART infusion between 2018 and 2021 at a multi-site single institution. bRT local control rate (LC), calculated based on the total number of irradiated sites, was defined from bRT end date. Progression-free survival (PFS) and overall-survival (OS) were defined from the date of CART infusion. In-field recurrence was defined as disease relapse occurring within the radiation planning target volume. Kaplan-Meier plots and cox regression modeling were used to estimate the desired output. Results: Median age of the cohort at time of CART infusion was 59 (range 19-73). The median equivalent 2 Gy dose (EQD2) administered was 23.3 Gy (range 4-41 Gy). The median time from end of bRT to CART infusion was 14 days (range 6-42). Five (14%) patients also received bridging chemotherapy with bRT. Among the 34 evaluable patients, 30 (88%) achieved an objective response (59% complete response and 29% partial response). At a median follow-up of 12 months, 1-year PFS was 48% and 1-year OS was 72%. No progression occurred beyond 240 days. On review of treatment plans and pre-treatment PET/CT scans, 59 sites were identified that received bRT prior to CART infusion. The median size and SUVmax of the irradiated sites were 8.7cm (range 1.5-22) and 13 (range 4-46), respectively. Of the 59 irradiated sites, 8 sites (13.6%) in 7 patients had in-field local recurrence, translating to 1-year LC of 84%. No in-field recurrence occurred beyond 180 days. Moreover, no local recurrence occurred in patients who received radiation to all known sites of active disease to EQD2> 30 Gy (n = 4 patients); these patients remained in remission except for 1 who experienced progression outside the bRT field. On univariate analysis, triple hit lymphoma (THL) (OR 22.8, 95% CI: 3.8-138.3; p < 0.001), tumor size (OR 1.25, 95% CI: 1.1-1.4; p < 0.001), specifically ≥ 9cm (OR 9.4, CI: 1.2-77.3; p = 0.036) and SUVmax (OR 1.1, CI: 1.02-1.15; p = 0.008), specifically ≥ 20 (OR 5.6, CI: 1.3-23.7; p = 0.018), were significantly associated with increased risk of in-field recurrence. On multivariate analysis, THL (OR 32.9, CI: 3.2-336.0; p = 0.03) and tumor size (OR 1.3, CI: 1.1-1.6; p = 0.01) retained significant association with in-field recurrence. Conclusions: Bridging radiotherapy prior to CART provides excellent and durable in-field local control for R/R B-cell NHL. Patients with triple hit histology and bulky disease are likely at higher risk of in-field recurrence and may benefit from higher doses of bRT.

Phase II trial of luspatercept with or without hydroxyurea for the treatment of patients with myelodysplastic/myeloproliferative neoplasms with ring sideroblasts and thrombocytosis or unclassifiable with ring sideroblasts

TPS7080

Background: Myelodysplastic syndrome/myeloproliferative neoplasms (MDS/MPN) are classified as a distinct category under the World Health Organization (WHO) classification of myeloid neoplasms. MDS/MPN with RS and thrombocytosis (MDS/MPN-RS-T) and MDS/MPN, unclassifiable with > 15% bone marrow ring sideroblasts (MDS/MPN-U-RS) have similar clinical and pathological characteristics with symptomatic or transfusion-dependent anemia as the predominant morbidity. Luspatercept has been approved in myelodysplastic syndromes with ring sideroblasts (MDS-RS) and MDS/MPN overlap syndromes, based on the phase 3 MEDALIST clinical trial which primarily included MDS-RS patients with an objective erythroid response rate of approximately 40 per cent. In this trial, some MDS-RS patients also experienced an increase in neutrophil and platelet counts. This raises a safety concern for MDS/MPN patients with elevated platelet or WBC counts such as MDS/MPN-RS-T and MDS/MPN-U-RS. Previous studies have shown clinical and biological differences between MDS-RS and MDS/MPN-RS-T, with the latter group at a significantly elevated risk for thrombotic events. Additionally, several MDS/MPN-RS-T patients are on hydroxyurea which may blunt the erythroid response of luspatercept. Therefore, it is imperative to establish the safety and efficacy of luspatercept in this patient group. Methods: This is an investigator-initiated, prospective, phase II study of luspatercept in MDS/MPN overlap neoplasms with ring sideroblasts and thrombocytosis or unclassifiable with ring sideroblasts with 2 arms; hydroxyurea-independent (cohort A) and hydroxyurea-dependent (cohort B). Hydroxyurea and/or aspirin use is allowed as per investigator discretion. The primary goal is to study the efficacy and safety of luspatercept in MDS/MPN-RS-T or MDS/MPN-U-RS with symptomatic anemia. The primary endpoint is to assess erythroid response rate as per the 2015 International Working Group MDS/MPN response criteria. Secondary endpoints include response duration, time to acute myeloid leukemia (AML) transformation, thrombosis rate, AML-free and overall survival. Inclusion criteria include newly diagnosed or relapsed/refractory adult patients with WHO-defined diagnosis of MDS/MPN-RS-T or MDS/MPN-U-RS with symptomatic or transfusion-dependent anemia and unlikely to respond (EPO level > 200 IU/L) or intolerant to erythropoiesis stimulating agent (ESA) therapy. Prior therapy with lenalidomide, hypomethylating agents or immunosuppressive therapy is allowed. The overall plan is to enroll 54 patients across the three Mayo Clinic sites, Minnesota, Arizona and Florida. Enrollment to the trial began in January 2022 with 1 patient enrolled at the time of abstract submission. Clinical trial information: NCT05005182.

Clinicopathologic characteristics and treatment outcomes of de novo myeloid sarcoma

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Background: Extramedullary disease in acute myeloid leukemia (AML), also known as myeloid sarcoma (MS), is an uncommon presentation of de novo AML. Clinicopathologic characteristics and optimal treatment strategies of de novo MS remain unclear in both isolated MS without bone marrow (BM) involvement and synchronous MS with BM involvement. Methods: In a single-site retrospective study, medical records of patients with de novo extramedullary AML who received oncological care at Mayo Clinic, Florida, between 1996 and 2021 were analyzed. Using BlueSky Statistics software, survival outcomes were analyzed using Kaplan-Meier and Cox-proportional hazard models for univariate and multivariate analysis, respectively. Results: 83 patients with de novo MS were identified; 49 (59%) presented with synchronous MS and 34 (41%) exhibited isolated MS. Median age at diagnosis was 56 years (range, 17-89); 63% were male. Next-generation sequencing of the blood +/- BM revealed abnormalities in 24/27 (88%) analyzed patients; aberrations included mutations in RTK-RAS pathways (12/27), NPM1 (10/27), TET2 (6/27), and IDH2 (4/27). Median length of follow-up was 1.73 years (95% CI; 0.03-3.0); 53 patients (64%) had expired. Median event free survival was 0.64 years and 0.61 years in isolated and synchronous MS, respectively (p = 0.5). Median overall survival (mOS) in isolated and synchronous MS was 2.1 years and 1.5 years, respectively (p = 0.5). Induction treatment with intensive chemotherapy (IC) was administered in 70 patients (84%). IC regimens included 7+3, MEC, CLAG-M, and hyper-CVAD. Variables associated with improved survival in both groups included treatment with IC +/- allogenic stem cell transplant (alloSCT) (p < 0.001), normal or favorable risk karyotype (p = 0.001), gastrointestinal, gynecological, or genitourinary site of involvement (p < 0.001), and age less than 60 (p = 0.001). Localized therapy (LT) did not provide an added survival benefit. Patients with synchronous MS were more likely to relapse in the BM and blood than isolated MS (p = 0.02). Conclusions: Enriched with RTK-RAS mutations, de novo MS remains an aggressive form of AML, particularly in patients with intermediate or high-risk genomics or those with skin, soft tissue, or lymphatic involvement. IC should be employed with consideration of alloSCT in eligible patients, particularly in synchronous MS due to a heightened risk for medullary and leukemic relapse.[Table: see text]

Treatment with anti-spike monoclonal antibodies in allogeneic HCT and CAR T-cell recipients with mild to moderate COVID-19: The Mayo Clinic experience

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Background: Prognosis of COVID-19 is poor in the setting of immunosuppression. Casirivimab/imdevimab (REGEN-COV), bamlanivimab, and sotrovimab are investigational monoclonal antibodies (MoAbs) authorized for treatment of mild/moderate COVID-19 for patients (pts) 12 years or older and who are at high-risk for progression to severe COVID-19. These neutralizing antibodies, against SARS-CoV-2 spike proteins, have been shown to decrease risk of progression to severe disease. Recipients of allogeneic stem cell transplants (allo-SCT) or chimeric antigen T cell therapy (CAR T cell) represent a high risk population. However, treatment outcomes with these MoAbs in these pts are not well described. Methods: This retrospective study included 33 consecutive adult pts who developed mild/moderate COVID-19 and received anti-spike SARS-CoV-2 MoAbs between December 2020 and November 2021. Allo-SCT (N=27) or CAR T cell (N=6) recipients were included, and outcomes were analyzed separately. Pts received REGEN-COV (N=19), bamlanivimab (N=11), or sotrovimab (N=1), missing (N=2). Results: In the allo-SCT cohort (N=27), median age at time of COVID-19 was 55 (23-76) years. Median time from allo-SCT to COVID-19 was 31 (22-64) months. Two pts received CAR T-cell therapy prior to allo-SCT. Diagnoses included leukemia or myeloid diseases (82%), lymphoma (11%), or myeloma (7%). Transplant characteristics are summarized (Table). Thirteen pts were vaccinated against SARS-CoV-2 prior to breakthrough COVID-19. Events considered included hospitalization due to COVID-19, disease progression, or death from any cause. The 6-month event-free and overall survivals were 81% and 91%, respectively. In the CAR T cell recipients cohort (N=6), 4 pts received axicabtagene ciloleucel for diffuse large B-cell or follicular lymphoma and 2 received brexucabtagene autoleucel for mantle cell lymphoma. The median follow-up was 8 (1-11) months. Two pts received autologous SCT prior to COVID-19. Median time from CAR T cell therapy to COVID-19 was 10 (3-24) months. Three pts were vaccinated prior to COVID-19. Only 1 pt was hospitalized due to severe COVID-19 requiring mechanical ventilation leading to death. Conclusions: These results show a potential benefit of MoAbs in high-risk pts, namely allo-SCT or CAR T cell recipients. Future studies should evaluate the role of prophylactic use MoAbs in these populations. A comparative analysis with a matched control cohort (who did not receive MoAbs) will be provided at the meeting. [Table: see text]

Male-specific late effects in adult hematopoietic cell transplantation recipients: a systematic review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation

Male-specific late effects after hematopoietic cell transplantation (HCT) include genital chronic graft-versus-host disease (GvHD), hypogonadism, sexual dysfunction, infertility, and subsequent malignancies. They may be closely intertwined and cause prolonged morbidity and decreased quality of life after HCT. We provide a systematic review of male-specific late effects in a collaboration between transplant physicians, endocrinologists, urologists, dermatologists, and sexual health professionals through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research, and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. The systematic review summarizes incidence, risk factors, screening, prevention and treatment of these complications and provides consensus evidence-based recommendations for clinical practice and future research.

The mutational landscape in chronic myelomonocytic leukemia and its impact on allogeneic hematopoietic cell transplantation outcomes: a Center for Blood and Marrow Transplantation Research (CIBMTR) analysis

Somatic mutations are recognized as an important prognostic factor in chronic myelomonocytic leukemia (CMML). However, limited data are available regarding their impact on outcomes after allogeneic hematopoietic cell transplantation (HCT). In this registry analysis conducted in collaboration with the Center for International Blood and Marrow Transplantation Registry database/sample repository, we identified 313 adult patients with CMML (median age: 64 years, range, 28- 77) who underwent allogeneic HCT during 2001-2017 and had an available biospecimen in the form of a peripheral blood sample obtained prior to the start of conditioning. In multivariate analysis, a CMML-specific prognostic scoring system (CPSS) score of intermediate-2 (HR=1.46, P=0.049) or high (HR=3.22, P=0.0004) correlated significantly with overall survival. When the molecularly informed CPSS-Mol prognostic model was applied, a high CPSS-Mol score (HR=2 P=0.0079) correlated significantly with overall survival. The most common somatic mutations were in ASXL1 (62%), TET2 (35%), KRAS/NRAS (33% combined), and SRSF2 (31%). DNMT3A and TP53 mutations were associated with decreased overall survival (HR=1.70 [95% CI: 1.11-2.60], P=0.0147 and HR=2.72 [95% CI: 1.37-5.39], P=0.0042, respectively) while DNMT3A, JAK2, and TP53 mutations were associated with decreased disease-free survival (HR=1.66 [95% CI: 1.11-2.49], P=0.0138, HR=1.79 [95% CI: 1.06-3.03], P=0.0293, and HR=2.94 [95% CI: 1.50-5.79], P=0.0018, respectively). The only mutation associated with increased relapse was TP53 (HR=2.94, P=0.0201). Nonetheless, the impact of TP53 mutations specifically should be interpreted cautiously given their rarity in CMML. We calculated the goodness of fit measured by Harrell's C-index for both the CPSS and CPSS-Mol, which were very similar. In summary, via registry data we have determined the mutational landscape in patients with CMML who underwent allogeneic HCT, and demonstrated an association between CPSS-Mol and transplant outcomes although without major improvement in the risk prediction beyond that provided by the CPSS.

Relapse and Disease-Free Survival in Patients With Myelodysplastic Syndrome Undergoing Allogeneic Hematopoietic Cell Transplantation Using Older Matched Sibling Donors vs Younger Matched Unrelated Donors

IMPORTANCE

Matched sibling donors (MSDs) are preferred for allogeneic hematopoietic cell transplantation (allo-HCT) in myelodysplastic syndrome even if they are older. However, whether older MSDs or younger human leukocyte antigen-matched unrelated donors (MUDs) are associated with better outcomes remains unclear.

OBJECTIVE

To investigate whether allo-HCT for myelodysplastic syndrome using younger MUDs would be associated with improved disease-free survival and less relapse compared with older MSDs.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study assessed data reported to the Center for International Blood and Marrow Transplant Research database from 1761 adults 50 years or older with myelodysplastic syndrome who underwent allo-HCT using an older MSD or younger MUD between January 1, 2011, and December 31, 2017, with a median follow-up of 48 months. Data analysis was performed from January 8, 2019, to December 30, 2020.

INTERVENTIONS/EXPOSURES

Allo-HCT from an older MSD (donor age ≥50 years) or a younger MUD (donor age ≤35 years).

MAIN OUTCOMES AND MEASURES

The primary outcome was disease-free survival. Secondary outcomes were overall survival, relapse, nonrelapse mortality, acute graft-vs-host disease (GVHD), chronic GVHD, and GVHD-free relapse-free survival.

RESULTS

Of 1761 patients (1162 [66%] male; median [range] age, 64.9 [50.2-77.6] years in the MSD cohort and 66.5 [50.4-80.9] years in MUD cohort), 646 underwent allo-HCT with an older MSD and 1115 with a younger MUD. In multivariable analysis, the rate of disease-free survival was significantly lower in allo-HCTs with older MSDs compared with younger MUDs (hazard ratio [HR], 1.17; 95% CI, 1.02-1.34; P = .02), whereas the difference in overall survival rate of allo-HCT with younger MUDs vs older MSDs was not statistically significant (HR, 1.13; 95% CI, 0.98-1.29; P = .07). Allo-HCT with older MSDs was associated with significantly higher relapse (HR, 1.62; 95% CI, 1.32-1.97; P < .001), lower nonrelapse mortality (HR, 0.76; 95% CI, 0.59-0.96; P = .02), lower acute GVHD (HR, 0.52; 95% CI, 0.42-0.65; P < .001), chronic GVHD (HR, 0.77; 95% CI, 0.64-0.92; P = .005), and a lower rate of GVHD-free relapse-free survival beyond 12 months after allo-HCT (HR, 1.42; 95% CI, 1.02-1.98; P = .04).

CONCLUSIONS AND RELEVANCE

This cohort study found higher disease-free survival and lower relapse for allo-HCT in myelodysplastic syndrome using younger MUDs compared with older MSDs. The risk of nonrelapse mortality and GVHD was lower with older MSDs. These results suggest that the use of younger MUDs should be considered in the donor selection algorithm for myelodysplastic syndrome, in which it is pivotal to minimize relapse given limited treatment options for managing relapsed disease.

Incidence of thrombosis in relapsed/refractory B-cell lymphoma treated with axicabtagene ciloleucel: Mayo Clinic experience

Chimeric antigen receptor (CAR) T-cell therapy is effective in relapsed/refractory large B-cell lymphoma and results in a unique toxicity profile, namely cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome. The hyper-inflammatory state associated with these toxicities has been suggested to increase the risk of thrombosis. We conducted a retrospective analysis of patients treated with axicabtagene ciloleucel (axi-cel) to assess the rate of thrombosis with axi-cel therapy from the time of CAR T-cell infusion until the end of hospitalization, when performed in the inpatient setting, or up to day +30 when performed in the outpatient setting. Ninety-two (95%) of 97 patients were hospitalized during axi-cel therapy and 85 (88%) developed CRS. Fifty-five patients (57%) received concurrent anticoagulation (53 as prophylaxis). Patients with prior VTE did not have progression or evidence of new VTE. Only 2 (2.1%) patients developed VTE. These results demonstrate a low-risk for thrombosis in axi-cel recipients.

Impact of Induction Therapy with VRD versus VCD on Outcomes in Patients with Multiple Myeloma in Partial Response or Better Undergoing Upfront Autologous Stem Cell Transplantation

Bortezomib-based triplet regimens-specifically bortezomib, lenalidomide, and dexamethasone (VRD) and bortezomib, cyclophosphamide, and dexamethasone (VCD)-are the 2 most common induction regimens used in transplantation-eligible patients with newly diagnosed multiple myeloma (NDMM), with conflicting data on comparative efficacy and outcomes in this population. We compared long-term outcomes of patients with NDMM receiving VRD induction and those receiving VCD induction prior to autologous stem cell transplantation (ASCT). Patients registered with the Center for International Blood and Marrow Transplant Registry were included if they had undergone ASCT for MM within 6 months of diagnosis between January 2013 and December 2018, received VRD or VCD induction, and achieved a pretransplantation partial or better response. Of 1135 patients, 914 received VRD and 221 received VCD. The patients receiving VCD were more likely to have renal impairment and International Staging System (ISS) stage III disease and less likely to receive full-dose melphalan (200 mg/m²) conditioning (69% versus 80%; P < .001). Very good partial response rates pretransplantation, post-transplantation, and at best response were not significantly different in the 2 groups. Maintenance use was more common after VRD induction (88% versus 76%; P < .001), with lenalidomide the most common agent (80% versus 63%). Patients in the VRD group had a higher rate of renal recovery (74% versus 43%; P < .001), possibly due to a rapid reduction of light chains in the VRD group or improvement in renal function with VCD, which allowed a switch over to VRD, as patients who switched were classified in the VRD group. Patients receiving VRD had better survival on univariate analysis, with a median progression-free survival (PFS) from transplantation of 44.6 months versus 34.1 months (P = .004) and median 5-year overall survival (OS) of 79% versus 60% (P < .001). Multivariate analysis showed no significant survival difference, with a hazard ratio for VCD versus VRD induction of 1.22 (95% CI, 0.96 to 1.55; P = .10) for PFS and 1.33 (95% CI, 0.93 to 1.92, P = .12) for OS. Maintenance use was independently associated with superior PFS and OS, along with ISS stage, cytogenetics, and pretransplantation response (PFS only). In patients with MM undergoing upfront ASCT after VRD or VCD induction, no independent survival difference was seen based on the induction therapy received after adjusting for other prognostic factors. The use of maintenance treatment was uniformly associated with superior outcomes. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Outcomes of Allogeneic Hematopoietic Cell Transplantation in T-cell Prolymphocytic Leukemia: A Contemporary Analysis from the Center for International Blood and Marrow Transplant Research

T cell prolymphocytic leukemia (T-PLL) is a rare, aggressive malignancy with limited treatment options and poor long-term survival. Previous studies of allogeneic hematopoietic cell transplantation (alloHCT) for T-PLL are limited by small numbers, and descriptions of patient and transplantation characteristics and outcomes after alloHCT are sparse. In this study, we evaluated outcomes of alloHCT in patients with T-PLL and attempted to identify predictors of post-transplantation relapse and survival. We conducted an analysis of data using the Center for International Blood and Marrow Transplant Research database on 266 patients with T-PLL who underwent alloHCT between 2008 and 2018. The 4-year rates of overall survival (OS), disease-free survival (DFS), relapse, and treatment-related mortality (TRM) were 30.0% (95% confidence interval [CI], 23.8% to 36.5%), 25.7% (95% CI, 20% to 32%), 41.9% (95% CI, 35.5% to 48.4%), and 32.4% (95% CI, 26.4% to 38.6%), respectively. In multivariable analyses, 3 variables were associated with inferior OS: receipt of a myeloablative conditioning (MAC) regimen (hazard ratio [HR], 2.18; P < .0001), age >60 years (HR, 1.61; P = .0053), and suboptimal performance status, defined by Karnofsky Performance Status (KPS) <90 (HR, 1.53; P = .0073). Receipt of an MAC regimen also was associated with increased TRM (HR, 3.31; P < .0001), an elevated cumulative incidence of grade II-IV acute graft-versus-host disease (HR, 2.94; P = .0011), and inferior DFS (HR, 1.86; P = .0004). Conditioning intensity was not associated with relapse; however, stable disease/progression was correlated with increased risk of relapse (HR, 2.13; P = .0072). Both in vivo T cell depletion (TCD) as part of conditioning and KPS <90 were associated with worse TRM and inferior DFS. Receipt of total body irradiation had no significant effect on OS, DFS, or TRM. Our data show that reduced-intensity conditioning without in vivo TCD (ie, without antithymocyte globulin or alemtuzumab) before alloHCT was associated with long-term DFS in patients with T-PLL who were age ≤60 years or who had a KPS >90 or chemosensitive disease.

Chronic Graft-versus-Host Disease, Nonrelapse Mortality, and Disease Relapse in Older versus Younger Adults Undergoing Matched Allogeneic Peripheral Blood Hematopoietic Cell Transplantation: A Center for International Blood and Marrow Transplant Research Analysis

The effect of chronic graft-versus-host disease (cGVHD) on the risk of nonrelapse mortality (NRM) and relapse has not been specifically studied in older adults, who are increasingly undergoing allogeneic hematopoietic cell transplantation (alloHCT) and surviving long-term to develop cGVHD. In this Center for International Blood and Marrow Transplant Research (CIBMTR) analysis, we tested our hypothesis that the risk of NRM was higher with the development of cGVHD, particularly among older adults (age ≥60 years). We included 4429 adults age ≥40 years who underwent a first HLA-matched peripheral blood stem cell alloHCT for acute myelogenous leukemia or myelodysplastic syndrome between 2008 and 2017. We compared outcomes of 4 groups-older adults (≥60 years) and younger adults (40 to 59 years) with cGVHD and older and younger adults without cGVHD-to determine the effect of older age and cGVHD on various outcomes. We used Cox proportional hazard models to determine the risk of NRM, relapse, and overall survival (OS). We treated cGVHD as a time-dependent covariate. The severity of cGVHD was based on the CIBMTR clinical definitions. cGVHD was significantly associated with a higher risk of NRM and lower risk of relapse regardless of age. The risk of NRM was higher for older adults versus younger adults. Adults who developed cGVHD as a group had longer OS compared with age-matched cohorts without cGVHD. Older adults had worse OS regardless of cGVHD. Among adults with cGVHD, clinically moderate or severe cGVHD was associated with a significantly higher risk of NRM and lower risk of relapse; severe cGVHD was associated with shorter OS, whereas mild to moderate cGVHD was associated with longer OS. Among both younger and older adults, the development of cGVHD was associated with a higher risk of NRM, lower risk of relapse, and longer OS. Older adults had a higher risk of NRM, but the increased risk of NRM associated with cGVHD did not differ based on age. The development of mild to moderate cGVHD offered the most favorable balance between minimizing NRM and decreasing the risk of relapse. The relapse risk was lowest for adults with severe cGVHD, but high NRM resulted in shorter OS. Developing strategies to avoid clinically severe cGVHD is critically important. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Does bridging radiation therapy affect the pattern of failure after CAR T-cell therapy in non-Hodgkin lymphoma?

PURPOSE

Analyze the pattern of disease failure after anti-CD19-directed chimeric antigen receptor T-cell therapy (CART) for non-Hodgkin lymphoma, assess the local control rate of bridging radiotherapy (bRT) and characterize in-field recurrences.

METHODS

We retrospectively reviewed 120 patients with NHL who received CART between 2018 and 2020. Baseline characteristics and treatment outcomes were compared between patients who received bRT and those who did not (noRT).

RESULTS

Of the 118 patients included, 14 (12%) received bRT, while 104 (88%) did not. bRT group had more localized and extranodal disease. bRT was delivered with a median dose of 20 Gy (range: 15-36) in 5 fractions (range: 3-24). Pattern of failure analysis revealed that progression involving pre-existing sites was the predominant pattern of failure in both the bRT and noRT groups (86% and 88%, respectively). Median duration of response was 128 days (range: 25-547) for bRT group and 93 days (range: 22-965) for noRT group (p = 0.78). In the bRT group, only 2/15 sites irradiated had infield recurrence and where characterized by bulky disease, SUV_max >20, elevated LDH at the time of CART infusion, and extranodal involvement. The bRT 1-year LC was 86%. Median duration of local response was 257 days (range: 25-630) for radiation-bridged sites.

CONCLUSION

Majority of progressions after CART infusion involve pre-existing sites. Bridging RT prior to CART provides excellent in-field local control and durable response. Patients with bulky disease, SUV_max >20, elevated LDH, and extranodal involvement are likely at higher risk of in-field recurrence after bRT and may benefit from higher curative doses of bRT.

Impact of depth of clinical response on outcomes of acute myeloid leukemia patients in first complete remission who undergo allogeneic hematopoietic cell transplantation

Acute myeloid leukemia (AML) patients often undergo allogeneic hematopoietic cell transplantation (alloHCT) in first complete remission (CR). We examined the effect of depth of clinical response, including incomplete count recovery (CRi) and/or measurable residual disease (MRD), in patients from the Center for International Blood and Marrow Transplantation Research (CIBMTR) registry. We identified 2492 adult patients (1799 CR and 693 CRi) who underwent alloHCT between January 1, 2007 and December 31, 2015. The primary outcome was overall survival (OS). Multivariable analysis was performed to adjust for patient-, disease-, and transplant-related factors. Baseline characteristics were similar. Patients in CRi compared to those in CR had an increased likelihood of death (HR: 1.27; 95% confidence interval: 1.13-1.43). Compared to CR, CRi was significantly associated with increased non-relapse mortality (NRM), shorter disease-free survival (DFS), and a trend toward increased relapse. Detectable MRD was associated with shorter OS, shorter DFS, higher NRM, and increased relapse compared to absence of MRD. The deleterious effects of CRi and MRD were independent. In this large CIBMTR cohort, survival outcomes differ among AML patients based on depth of CR and presence of MRD at the time of alloHCT. Further studies should focus on optimizing post-alloHCT outcomes for patients with responses less than CR.

Fludarabine and Melphalan Compared with Reduced Doses of Busulfan and Fludarabine Improve Transplantation Outcomes in Older Patients with Myelodysplastic Syndromes

Reduced-intensity conditioning (RIC) regimens developed to extend the use of allogeneic hematopoietic stem cell transplantation (HSCT) to older patients have resulted in encouraging outcomes. We aimed to compare the 2 most commonly used RIC regimens, i.v. fludarabine with busulfan (FluBu) and fludarabine with melphalan (FluMel), in patients with myelodysplastic syndrome (MDS). Through the Center for International Blood and Marrow Transplant Research (CIBMTR), we identified 1045 MDS patients age ≥60 years who underwent first HSCT with a matched related or matched (8/8) unrelated donor using an RIC regimen. The CIBMTR's definition of RIC was used: a regimen that incorporated an i.v. busulfan total dose ≤7.2 mg/kg or a low-dose melphalan total dose ≤150 mg/m². The 2 groups, recipients of FluBu (n = 697) and recipients of FluMel (n = 448), were comparable in terms of disease- and transplantation-related characteristics except for the more frequent use of antithymocyte globulin or alemtuzumab in the FluBu group (39% versus 31%). The median age was 67 years in both groups. FluMel was associated with a reduced relapse incidence (RI) compared with FluBu, with a 1-year adjusted incidence of 26% versus 44% (P ≤ .0001). Transplantation-related mortality (TRM) was higher in the FluMel group (26% versus 16%; P ≤ .0001). Because the magnitude of improvement with FluMel in RI was greater than the improvement in TRM with FluBu, disease-free survival (DFS) was better at 1 year and beyond with FluMel compared with FluBu (48% versus 40% at 1 year [P = .02] and 35% versus 27% at 3 years [P = .01]). Overall survival (OS) was comparable in the 2 groups at 1 year (63% versus 61%; P = .4) but was significantly improved with FluMel compared with FluBu at 3 years (46% versus 39%; P = .03). Our results suggest that FluMel is associated with superior DFS compared with FluBu owing to reduced RI in older patients with MDS patients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Patient perceptions of palliative care in the process of allogeneic hematopoietic cell transplantation

e24082

Background: Allogeneic hematopoietic cell transplantation (allo-HCT) is associated with significant short- and long-term sequelae that affect patients’ overall quality of life (QoL) and their physical and psychological well-being. Studies have shown improvement in patient QoL and physician satisfaction with palliative care involvement in the allo-HCT process. However, patient and physician perceptions regarding palliative care often impact timely referral. We conducted a prospective study to examine patient perceptions of palliative care both before and after palliative care consultation during evaluation for allo-HCT. Methods: This is a prospective, single-center study, of patients > 18 years of age, who were referred for a palliative care consultation as part of standard evaluation for allo-HCT. Patients were administered a pre- and post-visit internally derived questionnaire to assess their understanding and comfort level with palliative care. The primary objective of this study was to examine patient perceptions of palliative care consultation during evaluation for allo-HCT. Primary end point was the change in patient pre- and post- questionnaire responses. Secondary endpoint was the completion of advance care planning documentation pre- and post- consultation. Results: We enrolled 32 patients (male = 14) undergoing evaluation for allo-HCT with a primary diagnosis of AML (n = 8), NHL (n = 8), MDS (n = 7), ALL (n = 2), and other (n = 7). Following consultation with palliative care there was a statistically significant increase in patient understanding of the reason for the appointment, p = 0.0006. There was also a significant increase in patient’s knowledge of palliative care, with only 28% describing their knowledge as “good” or “excellent” prior to consultation and 79.3% after consultation, p < 0.0001. There was an observed positive, non-statistically significant, trend in patient comfort level with palliative medicine with only 20.7% (n = 6) describing their comfort as “high” or “very high” prior to consultation and 51.7% (n = 15) after consultation, p = 0.60. There was a higher rate of completion of advance care planning documentation following consultation with palliative medicine 56.3% vs 71.4%, p = 0.042. Conclusions: Palliative care consultation prior to allo-HCT increases a patient’s understanding of the role of palliative medicine as part of their allo-HCT and improves advance care planning. These findings need to be validated in a larger, multicenter, patient cohort.

A phase 4 study to evaluate outpatient blinatumomab in patients with minimal/measurable residual disease (MRD) positivity (+) of B-cell precursor acute lymphoblastic leukemia (BCP-ALL)

TPS7051

Background: The prognosis for adults with relapsed or refractory BCP-ALL is poor. MRD+ is the strongest predictor of relapse. Blinatumomab, a CD3/CD19-directed BiTE® (bispecific T-cell engager) molecule, is an effective treatment for patients with MRD+.1 Blinatumomab is administered as a continuous intravenous infusion (cIV) 28 days per cycle. Severe adverse events (AEs) such as cytokine release syndrome (CRS) and neurologic toxicity (NT) may occur; thus, hospitalization is recommended for the first 3 days of cycle 1 and the first 2 days of cycle 2 for MRD+ patients. However, the incidence of severe AEs is low in MRD+ BCP-ALL patients (CRS: 2%, NT: 13%).1 We believe that with the use of effective digital monitoring devices, blinatumomab can be safely administered for the entire 28-day cIV cycle as an outpatient. Methods: Adult patients (n = 45) with BCP-ALL in complete remission and MRD+ (≥0.1% blasts) are being enrolled at 25 planned treatment sites, endpoint: grade ≥3 AE during monitoring (Amgen NCT04506086). Patient suitability for blinatumomab and outpatient monitoring is established. Patients will receive 2-4 cycles of blinatumomab. Cycles are initiated in the outpatient setting, digital monitoring devices activated and attached, and patients sent home. Once home, patients set up the home hub and real-time remote data transfer to the healthcare professional (HCP) begins. The devices are worn continuously, 24 hours a day for the first 3 days of cycle 1 and the first 2 days of cycle 2 only. Devices: Current Health’s Wearable Monitoring System (CHWMS) is an FDA-cleared platform for wireless and wearable health monitoring of patients at home. The CHWMS provides continuous oxygen saturation, respiratory rate, and heart rate; an axillary temperature sensor is worn and provides continuous temperature. Patients manually measure blood pressure every 3-6 hours around the clock. Patients have an integrated mobile device (tablet) to initiate contact with the HCP if needed. HCP/designee has a mobile device (smart phone) and receives vital signs as a constant live feed transmitted from the CHWMS device. The CHWMS platform generates a loud audible alert based on pre-specified vital sign alarming thresholds or if there is an interruption in data transfer. HCP may initiate direct audio and video contact with the patient, assess the patient’s condition, and make an appropriate intervention. HCP may also initiate patient contact in the absence of an alert. Patients are required to have a caregiver present during the entire period of outpatient monitoring. Patients have a full set of replacement devices as well as a 24/7 hotline for device support. Trial enrollment is underway. This study may generate feasibility data on the effectiveness of home monitoring during blinatumomab infusion in patients with MRD+ BCP-ALL. 1Gökbuget, Blood, 2018. Clinical trial information: NCT04506086.

A phase 1 dose escalation and cohort expansion study of the safety and efficacy of allogeneic CRISPR-Cas9–engineered T cells (CTX110) in patients (Pts) with relapsed or refractory (R/R) B-cell malignancies (CARBON)

TPS7570

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common form of non-Hodgkin lymphoma (NHL), and although > 50% of pts achieve long-term remission with first-line therapy, pts with R/R disease as well as those with R/R grade 3b follicular lymphoma (FL), double-, or triple-hit high-grade lymphomas have poor long-term outcomes (Crump 2017; Kahl 2016; Jain 2012). Autologous (auto) chimeric antigen receptor (CAR) T cell therapy has provided additional options for pts with R/R disease, but only when leukapheresis and manufacturing prove feasible (Jacobson 2020). Allogeneic (allo) CAR-T cells were designed specifically to address these unmet needs by using healthy donor T cells to produce a readily available product and remove the need for bridging chemotherapy. We are currently investigating the safety and efficacy of CTX110, an allo anti-CD19 CAR-T cell product modified by using CRISPR/Cas9-editing to disrupt the endogenous T-cell receptor (TCR) alpha constant (TRAC) locus in order to remove TCR expression and disrupt β2-microglobulin, which eliminates major histocompatibility complex (MHC) class I expression. Disruption of the TCR should significantly reduce or eliminate risks of graft-versus-host disease and elimination of MHC class I expression may increase CAR-T cell persistence by mitigating CTX110 rejection. In addition, the anti-CD19 CAR transgene construct is precisely inserted into the TRAC locus. Methods: The Phase 1 CARBON trial (NCT04035434) is an open-label, multicenter, global study evaluating the safety and efficacy of CTX110 in pts ≥18 y with R/R DLBCL NOS, double- or triple-hit DLBCL, or transformed or grade 3b FL with ≥2 prior lines of therapy or who are ineligible for/refused prior auto hematopoietic stem cell transplant (HSCT). Pts who received prior auto CAR-T or allo HSCT are excluded. Pts will receive lymphodepleting chemotherapy with fludarabine 30mg/m2 and cyclophosphamide 500mg/m2 for 3 days, followed by CTX110 infusion. In part A, dose escalation will be performed using a 3+3 design. Upon completion of dose finding, the cohort will be expanded to further assess safety signals and efficacy including the primary efficacy endpoint of overall response rate. Key secondary efficacy endpoints include duration of response, progression-free survival, and overall survival. The trial is currently open and enrolling. Clinical trial information: NCT04035434.

Adult Philadelphia-like B-cell acute lymphoblastic leukemia: Characteristics, outcomes, and role of allogeneic hematopoietic cell transplantation in comparison to Philadelphia-positive and Philadelphia-negative acute lymphoblastic leukemia

7022

Background: Philadelphia-like Acute Lymphoblastic Leukemia (Ph-like ALL) is a high-risk subset of adult ALL. Until recently, there has not been a systematic platform to recognize this entity in clinical practice. Furthermore, data regarding the role of allogeneic hematopoietic cell transplantation (allo-HCT) is lacking. We conducted this study to identify patients with Ph-like ALL and describe their outcomes in comparison to Ph+ and Ph- ALL with emphasis on the role of allo-HCT. Methods: To identify cases of Ph-like ALL, available diagnostic cytogenetic pellets for patients in the Mayo Clinic ALL cohort (N=365) were tested using a targeted fluorescence in situ hybridization (FISH) panel developed by the Mayo Clinic Genomics Laboratory and includes probes to detect Ph-like-specific rearrangements (i.e., ABL1, ABL2, PDGFRB, JAK2 and CRLF2). Results: Thirty-three (9%) patients with Ph-like ALL were identified, the remaining patients were classified as Ph+ (N=132, 36%) or Ph- ALL (N=200, 55%). Patients with Ph-like ALL were younger (Median: 39 vs. 50 vs. 49 years, P=.01), had higher WBC (Median: 27.9 vs. 21.5 vs. 4.5 x109/L, P<.001), were less likely to achieve CR (91% vs. 99% vs. 96%, P=.02), more likely to be MRD+ (64% vs. 34% vs. 36%, P=.03), had a higher relapse rate (5-year: 39% vs. 24% vs. 38%, P=.01) and lower OS (5-year: 41% vs. 64% vs. 49%, P=.02), see Table. Patients who achieved MRD negativity had better OS (MRD+ vs MRD-, P=.01). Importantly, no statistically significant difference in OS, relapse or non-relapse mortality were noted between the 3 groups in patients who underwent allo-HCT in CR1. Conclusions: Ph-like ALL is a high risk subgroup with increased prevalence in younger adults. Allo-HCT appears to offset the poor prognosis associated with this entity. A targeted FISH panel offers timely recognition of this entity in a clinical setting.[Table: see text]

Systematic Reviews in Hematopoietic Cell Transplantation and Cellular Therapy: Considerations and Guidance from the American Society for Transplantation and Cellular Therapy, European Society for Blood and Marrow Transplantation, and Center for International Blood and Marrow Transplant Research Late Effects and Quality of Life Working Committee

Systematic reviews apply rigorous methodologies to address a prespecified, clearly formulated clinical research question. The conclusion that results is often cited to more robustly inform decision making by clinicians, third-party payers, and managed care organizations about the clinical question of interest. Although systematic reviews provide a rigorous standard, they may be infeasible when the task is to create general disease-focused guidelines comprising multiple clinical practice questions versus a single major clinical practice question. Collaborating transplantation and cellular therapy society committees also recognize that the quantity and or quality of reference sources may be insufficient for a meaningful systematic review. As the conduct of systematic reviews has evolved over time in terms of grading systems, reporting requirements, and use of technology, here we provide current guidance on methodologies, resources for reviewers, and approaches to overcome challenges in conducting systematic reviews in transplantation and cellular therapy.

Impact of hypoalbuminemia on the prognosis of relapsed/refractory B-cell lymphoma treated with axicabtagene ciloleucel

INTRODUCTION

Hypoalbuminemia is a known adverse prognostic factor in lymphomas. Yet, it is unknown if axicabtagene ciloleucel (axi-cel) overcomes the adverse prognostic impact of hypoalbuminemia in relapsed/refractory large B-cell lymphoma.

METHODS

We conducted a retrospective analysis across three Mayo Clinic centers to assess the relationship of hypoalbuminemia (defined as a serum albumin (SA) levels ≤ 3.5 g/dL) on outcomes of patients treated with axi-cel.

RESULTS

This analysis included 81 patients. Two patients had no available SA levels preceding axi-cel infusion. Eighteen patients (22.8%) had hypoalbuminemia with a median SA of 3.3 g/dL. Patients with normal SA had a statistically higher ORR than those without hypoalbuminemia (P = .018). There was no difference in 1-year PFS and OS between the group with hypoalbuminemia and the group with normal SA levels (48% vs 49%, P = .81) and (74% vs 73%, P = .97), respectively. There was no difference in the severity or median duration of cytokine release syndrome or neurotoxicity between the two groups.

CONCLUSION

Notwithstanding the limitations related to the relatively small sample size, axi-cel therapy appears to overcome the adverse effect of hypoalbuminemia on OS and PFS. Large multicenter clinical studies are certainly needed to validate these findings.

Systematic reviews in hematopoietic cell transplantation and cellular therapy: considerations and guidance from the American Society for Transplantation and Cellular Therapy, European Society for Blood and Marrow Transplantation, and the Center for International Blood and Marrow Transplant Research late effects and quality of life working committee

Systematic reviews apply rigorous methodologies to address a pre-specified, clearly formulated clinical research question. The conclusion that results is often cited to more robustly inform decision-making by clinicians, third-party payers and managed care organizations about the clinical question of interest. While systematic reviews provide a rigorous standard, they may be unfeasible when the task is to create general disease-focused guidelines comprised of multiple clinical practice questions versus a single major clinical practice question. Collaborating transplantation and cellular therapy societal committees also recognize that the quantity and or quality of reference sources may be insufficient for a meaningful systematic review. As the conduct of systematic reviews has evolved over time in terms of grading systems, reporting requirements and use of technology, here we provide current guidance in methodologies, resources for reviewers, and approaches to overcome challenges in conducting systematic reviews in transplantation and cellular therapy.

Primary peritoneal myeloid sarcoma in association with CBFB/MYH11 fusion

Myeloid sarcoma, also known as chloroma or granulocytic sarcoma is an extramedullary disease process that typically presents in association with acute myeloid leukemia during initial presentation or at relapse. Often associated with cytogenetic mutations, including t(8;21)(q22;q22); RUNX1/RUNX1T1, and less frequently with inv(16)(p13.1q22) or t(16;16)(p13.1;q22); CBFB/MYH11, myeloid sarcoma is most commonly discovered in skin, soft tissue, bone, and connective tissue. In rare circumstances, myeloid sarcoma can present without any evidence of bone marrow or leukemic involvement. These cases of de novo myeloid sarcoma are rare, and are commonly misdiagnosed due to similarities with other entities. We report an unusual case of a primary de novo peritoneal myeloid sarcoma, in association with inv(16)(p13;q22) and clonal heterogeneity at different sites of involvement, that has responded well to AML induction therapy and consolidation treatment with gemtuzumab ozogamicin and high dose cytarabine. Cytogenetics, immunophenotyping, and chromosomal analysis, were each critical in establishing a proper diagnosis as well as helping to develop appropriate therapeutic strategies for this rare entity.

Efficacy of allogeneic hematopoietic cell transplantation in patients with chronic phase CML resistant or intolerant to tyrosine kinase inhibitors

Approximately 15-20% of chronic myeloid leukemia (CML) patients fail tyrosine kinase inhibitor (TKI) therapy secondary to resistance or intolerance. In the pre-TKI era, front-line allogeneic hematopoietic cell transplantation (allo-HCT) represented the standard approach for patients with chronic phase-CML (CP-CML) who were deemed fit to tolerate the procedure and had a human leukocyte antigen compatible donor available. Currently, CP-CML patients are eligible for allo-HCT only if they fail more than one TKI and/or are intolerant to the drug. We performed a systematic review/meta-analysis of the available literature to assess the evidence regarding allo-HCT efficacy in CP-CML patients. Data from eligible studies were extracted in relation to benefits (overall survival [OS], progression-free survival, disease-free survival [DFS], complete remission [CR], and molecular response [MR]) and harms (nonrelapse mortality [NRM], relapse, and acute and chronic graft-versus-host disease), and stratified by age into adult and pediatric groups. For adult allo-HCT recipients, the pooled OS, DFS, CR and, MR were 84% [95% confidence interval (CI) 59-99%], 66% (95% CI 59-73%), 56% (95% CI 30-80%), and 88% (95% CI 62-98%), respectively. Pooled NRM and relapse were 20% (95% CI 15-26%) and 19% (95% CI 10-28%), respectively. For the pediatric group, the OS rate was reported in one study and was 91% (95% CI 72-99%). Our results suggest that allo-HCT is an effective treatment for TKI-resistant or TKI-intolerant CP-CML. Post-transplant strategies are still needed to further mitigate the risk of relapse.