Hamadani, Mehdi

Abstract Aims BMT CTN 1506 (“MORPHO”) was a global phase 3 study of post-hematopoietic cell transplantation (HCT) maintenance with gilteritinib versus placebo for patients with FLT3-ITD-mutated AML in CR1. The study did not meet its primary endpoint of improved relapse-free survival (RFS) for post-HCT gilteritinib, but subgroup analysis indicated a benefit for participants with pre-HCT measurable residual disease (MRD). Subgroup analysis also indicated a statistically significant benefit of post-HCT gilteritinib for participants in North America, but no benefit for those in Europe or Asia. RFS for the control arms in Europe and Asia was higher than anticipated, suggesting that participants with different disease biology may have accrued to the study in these different geographic regions. In the primary analysis of the study, pre-HCT FLT3 inhibitor use and MRD across the entire study population were both found to have impacted outcomes. Time from diagnosis to HCT, a reflection of local practice patterns, is also known to impact outcomes for FLT3-ITD AML. We hypothesized that local practice patterns of pre-HCT FLT3 inhibitor use and time from AML diagnosis to HCT could have influenced the disease biology of study pts at the time of enrollment. This would be predicted to result in pre-HCT MRD levels and could provide an explanation for the regional differences observed in the study outcome. Methods We conducted a post-hoc analysis of the data focusing on days from AML diagnosis to HCT, pre-HCT FLT3 inhibitor use, and FLT3-ITD MRD assessed by a high-sensitivity assay. Eligibility requirements included FLT3-ITD-mutated AML in first remission after intensive chemotherapy and HCT occurring within 12 months of achieving remission. Patients refractory to induction therapy, or those with a history of relapse, were ineligible. Results Accrual took place in 16 different countries, with 5 countries accounting for 79.7% of the total accrual: USA 42.7%; Japan 15.7%; Korea 8.4%; UK 6.7%; Germany 6.2%; other countries 20.2%. In two countries, USA and Germany (48.9% of total enrollment), participants underwent HCT a median of 119 days after AML diagnosis, and 90.2% were treated with a FLT3 inhibitor pre-HCT. In contrast, in Japan, Korea, the UK and the other 11 countries all combined, participants underwent HCT a median of 152.5 days after AML diagnosis, and only 30.8% received any FLT3 inhibitor pre-HCT. Amongst all participants, those transplanted < 120 days from AML diagnosis and/or those treated with FLT3 inhibition pre-HCT were more likely to have improved RFS from post-HCT gilteritinib. RFS was improved with post-HCT gilteritinib in the US and Germany (HR 0.397; CI 0.220-0.718), whereas no benefit was evident in all other countries combined (HR 1.184; CI 0.685-2.048). Pre-HCT MRD levels were significantly higher (P = 0.011) in participants transplanted within 120 days from diagnosis as well as in those treated with a FLT3 inhibitor pre-HCT and also transplanted within 120 days (P = 0.019). Pre-HCT MRD was dependent on both FLT3 inhibitor use and time to HCT, as participants treated with successive courses of chemotherapy + FLT3 inhibition had successively lower MRD by the time of HCT. Conclusions The time from AML diagnosis to HCT and FLT3 inhibitor use pre-HCT both appeared to impact MRD levels immediately prior to HCT, and geographic differences in these two practice patterns likely accounted for the regional differences in benefit from post-HCT gilteritinib observed in BMT CTN 1506. Successive courses of chemotherapy without FLT3 inhibition appears to have selected a more favorable risk (e.g., MRD-lower) population for enrollment. Successive courses of chemotherapy combined with FLT3 inhibition progressively eradicated MRD, such that a majority of participants undergoing HCT after 3 or 4 courses were MRD negative and therefore unlikely to benefit from post-HCT gilteritinib. These findings have implications for clinical practice. Increasing the number of courses of chemotherapy combined with FLT3 inhibition before HCT may lower MRD sufficiently to eliminate the need for post-HCT inhibition for some patients but, alternatively, the additional delay could increase the risk of pre-HCT relapse, preventing patients from receiving HCT in first remission.

Summary We investigated the outcomes of patients with advanced systemic mastocytosis (AdvSM) undergoing allogeneic haematopoietic cell therapy (alloHCT) in the US. Twenty‐seven adult (median age, 58 years) patients with AdvSM received alloHCT from 2014 to 2021. Most patients were white (93%), male (63%) and had systemic mastocytosis (SM) with associated haematological neoplasm (SM‐AHN, 70%), received peripheral blood grafts (89%) and non‐myeloablative regimens. KIT mutation was detected in 14 of the reported 16 patients (87.5%). Post‐transplantation cyclophosphamide (PTCy) was used in approximately 50% of the cohort. Approximately 1 year after alloHCT, median bone marrow mast cell burden decreased from 15% pre‐alloHCT to 1.5% (range 0–8) at 1 year post‐alloHCT. The median serum tryptase decreased from 55 ng/mL (range 3–400 ng/mL) pre‐alloHCT to 18 ng/mL (range 0–481 ng/mL) at 1 year post‐alloHCT. At 1 year, progression‐free survival (PFS) and overall survival (OS) were 59% (95% confidence interval [CI], 41%–77%) and 74% (95% CI, 56%–89%) respectively. In the subset of patients with SM‐AHN, 1‐year PFS and OS were 74% (52%–91%) and 79% (95% CI, 58%–94%) respectively. The cumulative incidence of relapse/progression for the entire population of patients with SM ( n = 27) was 4% (95% CI, 0–14) at 100 days and 15% (95% CI, 4–31) at 1 year. For the subset of patients with AHN, the cumulative incidence was 11% (95% CI, 1–28) at 100 days and 21% (95% CI, 6–42) at 1 year. Relapse/progression was the cause of death in six of 12 patients (5 died of AHN and 1 died of SM progression). Eighteen and nine patients received a KIT inhibitor before alloHCT and after alloHCT respectively. In addition, six patients received a KIT inhibitor for the treatment of relapse/progression of SM after alloHCT. Although it is difficult to delineate the exact effect of alloHCT and KIT inhibitors because of the size of the study in this era, the use of alloHCT and KIT inhibitors pre‐ and post‐ alloHCT is increasing. In the near future, larger studies are required to provide further insights into this subject.

Abstract Outcomes in classic Hodgkin lymphoma (cHL) have steadily improved; however, additional therapies are needed for patients who relapse or do not respond to novel agents. Here, we report the efficacy and safety of camidanlumab tesirine (Cami), an anti-CD25 antibody-drug conjugate, in patients with relapsed/refractory cHL after brentuximab vedotin/programmed cell death protein 1 inhibitor therapies from the phase 2 ADCT-301-201 study. Eligible patients were adults with cHL who had received ≥3 previous lines of systemic therapy (or ≥2 if ineligible for hematopoietic stem cell transplant). Patients received 45 μg/kg Cami (IV, once every 3 weeks) in cycles 1 to 2, followed by 30 μg/kg IV once every 3 weeks for ≤1 year. The primary end point was overall response rate (ORR) per 2014 Lugano classification. Secondary end points included complete response rate (CRR), progression-free survival (PFS), and overall survival (OS). In total, 117 patients were enrolled with a median age of 37.0 years (range, 19-87). The ORR was 70.1% (95% confidence interval [CI], 60.9-78.2), with a CRR of 33.3% (95% CI, 24.9-42.6). The median PFS was 9.13 months (95% CI, 5.3-15.0); median OS was not reached. Thirty-three (28.2%) patients discontinued treatment because of treatment-emergent adverse events; the most common reasons were skin and subcutaneous tissue disorders (n = 10 [8.5%] patients), infections and infestations (n = 5 [4.3%]), and nervous systems disorders (n = 5 [4.3%]). Guillain-Barré–type or polyradiculopathy-type events occurred in 8 (6.8%) patients. Cami was efficacious in this heavily pretreated population; however, the efficacy was overshadowed by substantial issues with the safety profile. This trial was registered at www.clinicaltrials.gov as #NCT04052997.

ABSTRACT Transformed follicular lymphoma (tFL) is typically associated with chemotherapy resistance and a poor prognosis. There are limited data regarding outcomes after CD19‐directed chimeric antigen receptor T‐cell (CAR T) therapy in relapsed/refractory (R/R) tFL. A total of 923 adult patients with R/R tFL who received commercial CD19 CAR T therapy between 2017 and 2023 were identified in the Center for International Blood and Marrow Transplant Research registry. Median age was 64 years (range: 30–86) and median prior lines of therapy was 4 (range: 1–18). Most patients (78%) received axicabtagene ciloleucel, with 67% of patients having resistant disease at the time of CAR T infusion. At a median follow‐up of 25 months (range: 1–72) from CAR T infusion, the 2‐year overall survival (OS) was 57% (95% CI: 53–60) and progression‐free survival (PFS) was 43% (95% CI: 40–47). The 2‐year cumulative incidences of relapse or progression (rel/prog) and non‐relapse mortality (NRM) were 47% (95% CI: 44–51) and 9% (95% CI: 7–11), respectively. The overall response rate to CAR T was 76%, with a complete response rate of 63%. Grade ≥ 3 cytokine release syndrome (CRS) was observed in 7.1% and grade ≥ 3 immune effector cell–associated neurologic syndrome (ICANS) in 21.6% of patients. Multivariable analysis suggested that resistant disease status at the time of CAR T, use of bridging therapy, and high comorbidity index ≥ 3 were associated with inferior PFS and OS. Older age ≥ 60 significantly increased the risk of NRM. Our study suggests that CD19 CAR T is effective and safe for tFL.

Abstract Brexucabtagene autoleucel (brexu-cel) is a chimeric antigen receptor T-cell therapy approved for relapsed/refractory mantle cell lymphoma (R/R MCL). Here, we report real-world effectiveness and safety outcomes of brexu-cel in a prospective study of patients with R/R MCL, including subgroups based on prior treatment with Bruton's tyrosine kinase inhibitor, bendamustine, or autologous hematopoietic cell transplant (auto-HCT) and number of prior therapy lines, using Center for International Blood and Marrow Transplant Research registry data. A total of 476 patients with R/R MCL who received brexu-cel between July 2020 and December 2022 were included in the analysis. With a median follow-up of 13.5 months, the overall response rate was 91% and complete response rate was 82%. One-year overall survival and progression-free survival rates were 76% and 63%, respectively. One-year cumulative incidence of nonrelapse mortality was 8%. Prior auto-HCT was associated with better duration of response within 6 months after infusion (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.28-0.85) but greater risk of immune effector cell–associated neurotoxicity syndrome (odds ratio [OR], 1.66; 95% CI, 1.06-2.60). Prior bendamustine was associated with increased risk of prolonged thrombocytopenia (OR, 1.90; 95% CI, 1.13-3.21). In patients with 1 to 2 prior therapy lines, relapse or progression was less frequent compared with those with ≥3 prior lines (HR, 0.64; 95% CI, 0.42-1.00). Collectively, our results suggest that real-world outcomes with brexu-cel were consistent with those of the ZUMA-2 trial, regardless of prior therapy type or number of prior therapy lines.

Summary CD19 chimeric antigen receptor T‐cell (CAR‐T) therapy is a pivotal part of the treatment algorithm for large B‐cell lymphoma (LBCL) in the second‐ and third‐line settings based on numerous clinical trials. However, these studies included very few patients with a diagnosis of high‐grade B‐cell lymphoma, not otherwise specified (HGBCL‐NOS) and it is unclear if outcomes are similar to those observed with more common LBCL histologies. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) registry, we identified 111 HGBCL‐NOS patients who received CAR‐T therapy. The cytokine release syndrome (CRS) rate was 74% (7.7% grade 3+), median onset was 4 days (1–17) and immune effector cell‐associated neurotoxicity syndrome rate was 45.2% (22.6% grade 3+), median onset was 7 days (1–17). At 2 years post‐CAR‐T infusion, the probability of overall survival and progression‐free survival were 41.6% and 28.7% respectively. The 2‐year non‐relapse mortality and relapse/progression were 3.1% (95% confidence interval [CI]: 0.6–7.6) and 68.1% (95% CI: 57.9–77.6) respectively. Our analysis illustrates that patients with HGBCL‐NOS represent a particularly difficult group to treat, even with CAR‐T therapy. We observed that one third of patients achieved a durable response; however, the overall results were less favourable, with lower overall response rate, overall survival and progression‐free survival as compared to published reports on LBCL.

Abstract Checkpoint inhibitors (CPIs) have shown remarkable efficacy in Hodgkin lymphoma (HL), and are now used routinely. While allogeneic hematopoietic cell transplantation (allo-HCT) remains a curative option for HL, there are concerns prior CPIs may exacerbate post–allo-HCT complications, particularly graft-versus-host disease (GVHD), and lead to worse outcomes. Given the relative paucity of data, we performed a Center for International Blood and Marrow Transplant Research/European Society for Blood and Marrow Transplantation study to examine the impact of prior CPIs in allo-HCT. We included 2186 adult patients aged >18 years who received a first allo-HCT using a matched related, unrelated, or haploidentical donor from 2008 to 2023. Twenty-seven percent of patients received prior CPIs. GVHD prophylaxis was posttransplant cyclophosphamide (PTCy) in 55.8% of patients in the CPI cohort, and 35% in the non-CPI cohort. Median follow-up among survivors was longer for the non-CPI (39 months) than CPI cohort (16.5 months). In multivariate analysis, prior CPI exposure did not affect overall survival (OS) or nonrelapse mortality, but resulted in improved progression-free survival (non-CPI vs CPI hazard ratio [HR], 0.81; 0.67-0.98; P = .03) and lower relapse incidence (HR, 0.58; 0.45-0.76; P < 001). While grade 2 to 4 (HR, 1.26; 1.04-1.53; P = .02) and 3 to 4 (HR, 1.41; 1.04-1.92; P = .03) acute GVHD (aGVHD) were increased, differences in chronic GVHD (cGVHD) were not significant. PTCy–based GVHD prophylaxis resulted in improved OS, lower grade 2 to 4 aGVHD, and cGVHD in patients with prior CPI exposure. In summary, allo-HCT should still be considered a curative option for patients with HL in the era of CPIs.

Abstract We conducted a post hoc analysis of data from Blood and Marrow Transplant Clinical Trials Network 1506 (MORPHO), a randomized trial of gilteritinib vs placebo as posttransplantation maintenance for patients with FLT3-ITD–mutated acute myeloid leukemia (AML) undergoing allogeneic hematopoietic cell transplantation (HCT), focusing the interactions between conditioning regimen intensity, measurable residual disease (MRD), and NPM1 comutation status reported from diagnosis. Comparing FLT3-ITD MRD before and after conditioning, there was no difference between myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC) in eradication or reduction of FLT3-ITD MRD. For participants who were FLT3-ITD MRD negative before HCT, there was no difference in the cumulative incidence of relapse during follow-up between those receiving MAC vs RIC. NPM1 comutation was associated with the largest magnitude of relapse-free survival benefit from post-HCT gilteritinib, and in these participants, post-HCT gilteritinib in the setting of RIC appeared to be as effective as MAC at preventing relapse. MAC appeared superior to RIC in preventing relapse only in participants who were NPM1 wild type at diagnosis and FLT3-ITD MRD positive before HCT. Our findings suggest that only a subset of patients with FLT3-ITD AML undergoing HCT may benefit from MAC and that, similar to AML therapy before HCT, the intensity of the HCT regimen should be adapted according to the molecular features of the disease. This trial was registered at www.clinicaltrials.gov as #NCT02997202.

ABSTRACTAlthough recent studies have demonstrated the efficacy of chimeric antigen receptor T‐cell (CAR‐T) therapy in relapsed large B‐cell lymphoma (LBCL) with MYC rearrangement (R‐MYC), the data comparing CAR‐T to autologous hematopoietic cell transplant (auto‐HCT) in such patients who achieve a complete or partial response (CR/PR) after salvage therapies are limited. We compared the clinical outcomes of patients with R‐MYC LBCL (including double and triple hit lymphomas) who underwent CAR‐T or auto‐HCT after achieving a CR/PR with salvage therapies using the Center for International Blood & Marrow Transplant Research registry. Among the 252 patients (auto‐HCT = 98, CAR‐T = 154), relative to auto‐HCT, CAR‐T was associated with significantly lower overall survival (OS) (Hazard Ratio [HR] 2.09, 95% CI 1.38–3.15, p < 0.001) on multivariate analysis. There were no differences in progression‐free survival (PFS) (HR 1.21, 95% CI 0.81–1.8 p = 0.36), risk of relapse (HR 1.1, 95% CI 0.71–1.69 p = 0.68), nonrelapse mortality (NRM) (HR 1.74, 95% CI 0.64–4.7 p = 0.28) while the post‐relapse survival was longer in auto‐HCT relative to CAR‐T (HR 1.93, 95% CI 1.21–3.06 p = 0.01). On propensity score matched analysis accounting for differences in characteristics across the two cohorts, we detected no significant differences in OS (HR 1.72, 95% CI 0.92–3.21 p = 0.09), PFS (HR 1.04, 95% CI 0.64–1.68 p = 0.88), NRM (HR 1.22, 95% CI 0.35–4.2 p = 0.76), relapse (HR = 0.93, 95% CI 0.54–1.6 p = 0.8) and post‐relapse survival (HR 2.25, 95% CI 0.98–5.17, p = 0.06). These data, although retrospective, support consideration for auto‐HCT in patients with R‐MYC LBCL who achieve a CR/PR after salvage therapies, particularly in regions with no or limited access to CAR‐T.