Clonal Hematopoiesis and Therapy-Related Myeloid Neoplasms After Autologous Transplant for Hodgkin Lymphoma

PURPOSE

Therapy-related myeloid neoplasm (t-MN) is a life-threatening complication of autologous peripheral blood stem cell transplantation (aPBSCT) for Hodgkin lymphoma (HL). Although previous studies have reported an association between clonal hematopoiesis (CH) in the infused PBSC product and subsequent post-aPBSCT risk of t-MN in patients with non-HL, information about patients with HL treated with aPBSCT is not available.

METHODS

We constructed a retrospective cohort of 321 patients with HL transplanted at a median age of 34 years (range, 18-71). Targeted DNA sequencing of PBSC products performed for CH-associated or myeloid malignancy-associated genes identified pathogenic mutations in these patients.

RESULTS

CH was identified in the PBSC product of 46 patients (14.3%) with most prominent representation of DNMT3A (n = 25), PPM1D (n = 7), TET2 (n = 7), and TP53 (n = 5) mutations. Presence of CH in the PBSC product was an independent predictor of t-MN (adjusted hazard ratio [aHR], 4.50 [95% CI, 1.54 to 13.19]). Notably all patients with TP53 mutations in the PBSC product developed t-MN, whereas none of the patients with DNMT3A mutations alone (without co-occurring TP53 or PPM1D mutations) did. Presence of TP53 and/or PPM1D mutations was associated with a 7.29-fold higher hazard of t-MN when compared with individuals carrying no CH mutations (95% CI, 1.72 to 30.94). The presence of TP53 and/or PPM1D mutations was also associated with a 4.17-fold higher hazard of nonrelapse mortality (95% CI, 1.25 to 13.87). There was no association between CH and relapse-related mortality.

CONCLUSION

The presence of TP53 and/or PPM1D mutations in the PBSC product increases the risk of post-aPBSCT t-MN and nonrelapse mortality among patients with HL and may support alternative therapeutic strategies.

Body composition and late-occurring chronic health conditions after autologous stem cell transplantation for lymphoma

BACKGROUND

Autologous peripheral blood stem cell transplantation (aPBSCT) is the standard of care for adults with relapsed lymphoma, yet recipients remain at risk of developing chronic health conditions (CHCs). It was hypothesized that body composition measurements of skeletal muscle and fat are associated with late-onset CHCs and nonrelapse mortality after aPBSCT.

METHODS

Leveraging the Blood or Marrow Transplant Survivor Study, we examined association between pre-aPBSCT body composition and new-onset grade 3-5 CHCs among 187 adults with lymphoma treated with aPBSCT (2011-2014) surviving ≥2 years after aPBSCT. Using computed tomography scans at the L3 level, skeletal muscle mass (skeletal muscle area and skeletal muscle density [SMD]) and body fat (subcutaneous adipose tissue and visceral adipose tissue) were measured and quantified as sex-specific z-scores. Competing risk models were built to study the impact of body composition on incident grade 3 through 5 CHCs and nonrelapse mortality (NRM) adjusting for confounders.

RESULTS

The study cohort had a median age at aPBSCT of 57 years with 63% males, 77% non-Hispanic Whites and 81% with non-Hodgkin lymphoma. The 5-year cumulative incidence of grade 3 through 5 CHCs was 47% (95% Confidence Interval, CI, 38%-56%). Each SD increase in SMD was associated with 30% reduced risk of grade 3 through 5 CHCs (95% CI, 0.50-0.96). The 10-year cumulative incidence of NRM was 16% (95% CI, 10-22). No body composition measure was associated with NRM.

CONCLUSIONS

The association between SMD and grade 3 through 5 CHCs following aPBSCT could inform development of prognostic models to identify adults with lymphoma at greatest risk of morbidity following aPBSCT.

Pre-frailty after blood or marrow transplantation and the risk of subsequent mortality

We examined the prevalence, risk factors, and association between pre-frailty and subsequent mortality after blood or marrow transplantation (BMT). Study participants were drawn from the BMT Survivor Study (BMTSS) and included 3346 individuals who underwent BMT between 1974 and 2014 at one of three transplant centers and survived ≥2 years post-BMT. Participants completed the BMTSS survey at a median of 9 years from BMT and were followed for subsequent mortality for a median of 5 years after survey completion. Closest-age and same-sex biological siblings also completed the survey. Previously published self-reported indices (exhaustion, weakness, low energy expenditure, slowness, unintentional weight loss) classified participants as non-frail (0-1 indices) or pre-frail (2 indices). National Death Index was used to determine vital status and cause of death. Overall, 626 (18.7%) BMT survivors were pre-frail. BMT survivors had a 3.2-fold higher odds of being pre-frail (95% CI = 1.9-5.3) compared to siblings. Compared to non-frail survivors, pre-frail survivors had higher hazards of all-cause mortality (adjusted hazard ratio [aHR] = 1.6, 95% CI = 1.4-2.0). Female sex, pre-BMT radiation, smoking, lack of exercise, anxiety, and severe/life-threatening chronic health conditions were associated with pre-frailty. The novel association between pre-frailty and subsequent mortality provides evidence for interventions as pre-frail individuals may transition back to their robust state.

Immunometabolic Adaptation of CD19-Targeted CAR T Cells in the Central Nervous System Microenvironment of Patients Promotes Memory Development

Metabolic reprogramming is a hallmark of T-cell activation, and metabolic fitness is fundamental for T-cell-mediated antitumor immunity. Insights into the metabolic plasticity of chimeric antigen receptor (CAR) T cells in patients could help identify approaches to improve their efficacy in treating cancer. Here, we investigated the spatiotemporal immunometabolic adaptation of CD19-targeted CAR T cells using clinical samples from CAR T-cell-treated patients. Context-dependent immunometabolic adaptation of CAR T cells demonstrated the link between their metabolism, activation, differentiation, function, and local microenvironment. Specifically, compared with the peripheral blood, low lipid availability, high IL15, and low TGFβ in the central nervous system microenvironment promoted immunometabolic adaptation of CAR T cells, including upregulation of a lipolytic signature and memory properties. Pharmacologic inhibition of lipolysis in cerebrospinal fluid led to decreased CAR T-cell survival. Furthermore, manufacturing CAR T cells in cerebrospinal fluid enhanced their metabolic fitness and antileukemic activity. Overall, this study elucidates spatiotemporal immunometabolic rewiring of CAR T cells in patients and demonstrates that these adaptations can be exploited to maximize the therapeutic efficacy of CAR T cells.

SIGNIFICANCE

The spatiotemporal immunometabolic landscape of CD19-targeted CAR T cells from patients reveals metabolic adaptations in specific microenvironments that can be exploited to maximize the therapeutic efficacy of CAR T cells.

Locoregional delivery of IL-13Rα2-targeting CAR-T cells in recurrent high-grade glioma: a phase 1 trial

Chimeric antigen receptor T cell (CAR-T) therapy is an emerging strategy to improve treatment outcomes for recurrent high-grade glioma, a cancer that responds poorly to current therapies. Here we report a completed phase I trial evaluating IL-13Rα2-targeted CAR-T cells in 65 patients with recurrent high-grade glioma, the majority being recurrent glioblastoma (rGBM). Primary objectives were safety and feasibility, maximum tolerated dose/maximum feasible dose and a recommended phase 2 dose plan. Secondary objectives included overall survival, disease response, cytokine dynamics and tumor immune contexture biomarkers. This trial evolved to evaluate three routes of locoregional T cell administration (intratumoral (ICT), intraventricular (ICV) and dual ICT/ICV) and two manufacturing platforms, culminating in arm 5, which utilized dual ICT/ICV delivery and an optimized manufacturing process. Locoregional CAR-T cell administration was feasible and well tolerated, and as there were no dose-limiting toxicities across all arms, a maximum tolerated dose was not determined. Probable treatment-related grade 3+ toxicities were one grade 3 encephalopathy and one grade 3 ataxia. A clinical maximum feasible dose of 200 × 106 CAR-T cells per infusion cycle was achieved for arm 5; however, other arms either did not test or achieve this dose due to manufacturing feasibility. A recommended phase 2 dose will be refined in future studies based on data from this trial. Stable disease or better was achieved in 50% (29/58) of patients, with two partial responses, one complete response and a second complete response after additional CAR-T cycles off protocol. For rGBM, median overall survival for all patients was 7.7 months and for arm 5 was 10.2 months. Central nervous system increases in inflammatory cytokines, including IFNγ, CXCL9 and CXCL10, were associated with CAR-T cell administration and bioactivity. Pretreatment intratumoral CD3 T cell levels were positively associated with survival. These findings demonstrate that locoregional IL-13Rα2-targeted CAR-T therapy is safe with promising clinical activity in a subset of patients. ClinicalTrials.gov Identifier: NCT02208362 .

Health care utilization by long-term survivors of blood or marrow transplantation-A Bone Marrow Transplant Survivor Study report

BACKGROUND

Blood or marrow transplantation (BMT) survivors carry a high burden of morbidity, yet health care utilization by this vulnerable population remains understudied. Patterns and predictors of various domains of health care utilization in long-term BMT survivors were evaluated.

METHODS

Study participants were drawn from the Bone Marrow Transplant Survivor Study (BMTSS). Patients transplanted between 1974 and 2014 at one of three transplant centers who had survived ≥2 years after BMT and were aged ≥18 years at the time of the study were included. A BMTSS survey served as the source of data for health care utilization, sociodemographics, and chronic health conditions. Domains of health care utilization in the 2 years preceding study participation included routine checkups, BMT-related visits, transplant/cancer center visits, emergency room (ER) visits, hospitalizations, and high health care utilization (≥7 physician visits during the 2 years before the study). Clinical characteristics and therapeutic exposures were abstracted from medical records.

RESULTS

In this cohort of 3342 BMT survivors (52% allogeneic), the prevalence of health care utilization declined over time since BMT for both allogeneic and autologous BMT survivors, such that among those who had survived ≥20 years, only 49%-53% had undergone routine checkups, 37%-38% reported BMT-related visits, and 28%-29% reported transplant/cancer center visits. The presence of severe/life-threatening conditions and chronic graft-vs-host disease increased the odds of health care utilization across all domains. Lower education, lack of insurance, and Hispanic ethnicity were associated with a lower prevalence of routine checkups and/or transplant/cancer center visits. Lower income increased the odds of ER visits but reduced the odds of hospitalizations or high health care utilization.

CONCLUSIONS

This study identified vulnerable populations of long-term BMT survivors who would benefit from specialized risk-based anticipatory care to reduce high health care utilization, ER visits, and hospitalizations.

A phase II randomized, placebo-controlled, multicenter trial to evaluate the efficacy of cytomegalovirus PepVax vaccine in preventing cytomegalovirus reactivation and disease after allogeneic hematopoietic stem cell transplant

Not available.

Dexamethasone potentiates chimeric antigen receptor T cell persistence and function by enhancing IL-7Rα expression

Dexamethasone (dex) is a glucocorticoid that is a mainstay for the treatment of inflammatory pathologies, including immunotherapy-associated toxicities, yet the specific impact of dex on the activity of CAR T cells is not fully understood. We assessed whether dex treatment given ex vivo or as an adjuvant in vivo with CAR T cells impacted the phenotype or function of CAR T cells. We demonstrated that CAR T cell expansion and function were not inhibited by dex. We confirmed this observation using multiple CAR constructs and tumor models, suggesting that this is a general phenomenon. Moreover, we determined that dex upregulated interleukin-7 receptor α on CAR T cells and increased the expression of genes involved in activation, migration, and persistence when supplemented ex vivo. Direct delivery of dex and IL-7 into tumor-bearing mice resulted in increased persistence of adoptively transferred CAR T cells and complete tumor regression. Overall, our studies provide insight into the use of dex to enhance CAR T cell therapy and represent potential novel strategies for augmenting CAR T cell function during production as well as following infusion into patients.

Sirolimus Is an Acceptable Alternative to Tacrolimus for Graft-versus-Host Disease Prophylaxis after Haploidentical Peripheral Blood Stem Cell Transplantation with Post-Transplantation Cyclophosphamide

Graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (PTCy), tacrolimus (Tac), and mycophenolate mofetil (MMF) for allogeneic haploidentical donor (haplo) hematopoietic cell transplantation (HCT) results in comparable outcomes to matched unrelated donor HCT. A phase II study from the Moffitt Cancer Center substituting sirolimus (Siro) for Tac in this prophylactic regimen reported comparable rates of grade II-IV acute GVHD (aGVHD). Many centers have substituted Siro for Tac in this setting based on a preferable side effect profile, although comparative data are limited. In this study, we retrospectively compared outcomes in haplo-HCT with PTCy/Siro/MMF versus haplo-HCT with PTCy/Tac/MMF. The study cohort included all consecutive patients receiving haploidentical donor T cell-replete peripheral blood stem cell (PBSC) HCT for hematologic malignancies at Moffitt Cancer Center or the City of Hope National Medical Center between 2014 and 2019. A total of 423 patients were included, of whom 84 (20%) received PTCy/Siro/MMF and 339 (80%) received PTCy/Tac/MMF. The median age for the entire cohort was 54 years (range, 18 to 78 years), and the median follow-up was 30 months. The Siro group had a higher proportion of patients age ≥60 years (58% versus 34%; P < .01), and the groups also differed in diagnosis type, conditioning regimen, and cytomegalovirus serostatus. There were no significant differences in the rates of grade II-IV aGVHD (45% versus 47%; P = .6) at day +100 or chronic GVHD (cGVHD) (47% versus 54%; P = .79) at 2 years post-HCT. In multivariate analysis, neutrophil engraftment at day +30 was significantly better in the Tac group (odds ratio, .30; 95% confidence interval, .1 to .83; P = .02), with a median time to engraftment of 17 days versus 18 days in the Siro group, but platelet engraftment was similar in the 2 groups. Otherwise, in multivariate analysis, GVHD prophylaxis type had no significant influence on aGVHD or cGVHD, nonrelapse mortality, relapse, GVHD-free relapse-free survival, disease-free survival, or overall survival after PBSC haplo-HCT. These findings suggest that Siro is a comparable alternative to Tac in combination with PTCy/MMF for GVHD prophylaxis, with overall similar clinical outcomes despite delayed engraftment after peripheral blood stem cell haplo-HCT. Although Tac remains the standard of care, Siro may be substituted based on the side effect profile of these medications, with consideration of patient medical comorbidities at HCT.

Results from a phase I trial of pembrolizumab plus vorinostat in relapsed/refractory B-cell non-Hodgkin lymphoma

Outcomes after programmed death-1 (PD-1) blockade in B-cell lymphomas are disappointing with few durable responses. Histone deacetylase inhibitors exhibit favorable immunomodulatory effects and demonstrate synergistic anti-tumor immune responses with anti-PD-1 therapy in preclinical models. We, therefore, developed a phase I study to evaluate the safety and preliminary efficacy of pembrolizumab with vorinostat in relapsed/refractory B-cell lymphomas. Patients were treated in a dose-escalation cohort using a Rolling 6 design followed by an expansion cohort at the recommended phase II dose (R2PD). Fifty-two patients were enrolled (32 Hodgkin and 20 non-Hodgkin lymphoma [NHL]). Here, we report safety data from the dose escalation cohort, and the toxicity and efficacy within NHL patients. Vorinostat was administered twice daily on days 1-5 and 8-12 (dose-level [DL]1: 100 mg; DL2: 200 mg) and pembrolizumab (200 mg) was administered on day 1 of each 3-week cycle. Of six patients treated at DL1, one had a dose-limiting toxicity (DLT) (Stevens-Johnson syndrome [SJS]), and one of six had a DLT at DL2 (thromboembolism); therefore, DL2 was the RP2D. The patient developing SJS was treated with corticosteroids, infliximab, and cyclosporine but ultimately died of invasive fungal infection from the extensive immunosuppression used to treat the SJS. The most common adverse events were hypertension, diarrhea, and cytopenias. Of 20 NHL patients, nine had follicular lymphoma (FL) and 11 had diffuse large B-cell lymphoma (DLBCL). Five DLBCL patients had primary mediastinal B-cell lymphoma (PMBL). The complete and overall response rates (CR and ORR) were 11% and 22% for FL and 45% and 55% for all DLBCL. Amongst DLBCL, the CR and ORR was 80% and 80% for PMBL and 17% and 33% for non-PMBL. In conclusion, pembrolizumab with vorinostat was tolerable and produced responses in relapsed/refractory B-cell NHL, with particularly notable efficacy in PMBL (clinicaltrials gov. Identifier: NCT03150329).

Clonal Hematopoiesis and Cardiovascular Disease in Patients With Multiple Myeloma Undergoing Hematopoietic Cell Transplant

Importance

There is a paucity of information on the association between clonal hematopoiesis of indeterminate potential (CHIP) and cardiovascular disease (CVD) in patients with cancer, including those with multiple myeloma (MM) undergoing hematopoietic cell transplant (HCT), a population at high risk of developing CVD after HCT.

Objective

To examine the association between CHIP and CVD in patients with MM and to describe modifiers of CVD risk among those with CHIP.

Design, Setting, and Participants

This was a retrospective cohort study of patients with MM who underwent HCT between 2010 and 2016 at City of Hope Comprehensive Cancer Center in Duarte, California, and had pre-HCT mobilized peripheral blood stem cell (PBSC) products cryopreserved and accessible for CHIP analyses. The study team performed targeted panel DNA sequencing to detect the presence of CHIP (variant allele frequency 2% or more).

Main Outcomes and Measures

The primary end point was the 5-year cumulative incidence and risk for developing de novo CVD (heart failure, coronary artery disease, or stroke) after HCT.

Results

Of 1036 consecutive patients with MM (580 male [56%]; median age, 60.0 years) who underwent a first autologous HCT, 201 patients had at least 1 CHIP variant (19.4%) and 35 patients had 2 or more variants (3.4%). The 5-year incidence of CVD was significantly higher in patients with CHIP (21.1% vs 8.4%; P < .001) compared with those without CHIP; the 5-year incidence among those with 2 or more variants was 25.6%. In the multivariable model, CHIP was associated with increased risk of CVD (hazard ratio [HR], 2.72; 95% CI, 1.70-4.39), as well as of individual outcomes of interest, including heart failure (HR, 4.02; 95% CI, 2.32-6.98), coronary artery disease (HR, 2.22; 95% CI, 1.06-4.63), and stroke (HR, 3.02; 95% CI, 1.07-8.52). Patients who had both CHIP and preexisting hypertension or dyslipidemia were at nearly 7-fold and 4-fold increased risk of CVD, respectively (reference: no CHIP, no hypertension, or dyslipidemia).

Conclusion and Relevance

CHIP was significantly and independently associated with risk of CVD in patients with MM undergoing HCT and may serve as a novel biologically plausible biomarker for CVD in this cohort. Patients with MM and both CHIP and cardiovascular risk factors had an exceptionally high risk of CVD. Additional studies are warranted to determine if cardiovascular preventive measures can reduce CHIP-associated CVD risk.

Myeloid lineage switch following CD7-targeted chimeric antigen receptor T-cell therapy in relapsed/refractory T-cell acute lymphoblastic leukemia

Not available.

Risky health behaviors and subsequent late mortality after blood or marrow transplantation: a BMTSS report

We examined the association between risky health behaviors (smoking, heavy alcohol consumption, and lack of vigorous physical activity) and all-cause and cause-specific late mortality after blood or marrow transplantation (BMT) to understand the role played by potentially modifiable risk factors. Study participants were drawn from the BMT Survivor Study (BMTSS) and included patients who received transplantation between 1974 and 2014, had survived ≥2 years after BMT, and were aged ≥18 years at study entry. Survivors provided information on sociodemographic characteristics, chronic health conditions, and health behaviors. National Death Index was used to determine survival and cause of death. Multivariable regression analyses determined the association between risky health behaviors and all-cause mortality (Cox regression) and nonrecurrence-related mortality (NRM; subdistribution hazard regression), after adjusting for relevant sociodemographic, clinical variables and therapeutic exposures. Overall, 3866 participants completed the BMTSS survey and were followed for a median of 5 years to death or 31 December 2021; and 856 participants (22.1%) died after survey completion. Risky health behaviors were associated with increased hazard of all-cause mortality (adjusted hazard ratio [aHR] former smoker, 1.2; aHR current smoker, 1.7; reference, nonsmoker; aHR heavy drinker, 1.4; reference, nonheavy drinker; and aHR no vigorous activity, 1.2; reference, vigorous activity) and NRM (aHR former smoker, 1.3; aHR current smoker, 1.6; reference, nonsmoker; aHR heavy drinker, 1.4; reference: nonheavy drinker; and aHR no vigorous activity, 1.2; reference, vigorous activity). The association between potentially modifiable risky health behaviors and late mortality offers opportunities for development of interventions to improve both the quality and quantity of life after BMT.

Ex-vivo CS1-OKT3 dual specific bivalent antibody-armed effector T cells mediate cellular immunity against multiple myeloma

Bispecific T cell engaging antibodies (bsAbs) have emerged as novel and powerful therapeutic agents for redirecting T cells towards antigen-specific tumor killing. The cell surface glycoprotein and SLAM family member, CS1, exhibits stable and high-level expression on malignant plasma cells including multiple myeloma, which is indicative of an ideal target for bsAb therapy. Here, we developed a CS1 bsAb (CS1-dbBiTE) using Click chemistry to conjugate intact anti-CS1 antibody (Elotuzumab) and anti-huOKT3 antibody at their respective hinge regions. Using a cellular therapy approach, human T cells were armed ex-vivo with CS1-dbBiTE prior to examining effector activity. Our data indicates that arming T cells with CS1-dbBiTE induced T cell activation and expansion and subsequent cytotoxic activity against CS1-bearing MM tumors, demonstrated by significant CD107a expression as well as inflammatory cytokine secretion. As expected, CS1-dbBiTE armed T cells showed significantly reduced effector activity in the absence of CS1 expression. Similarly, in MM mouse xenograft studies, armed T cells exhibited effective anti-tumor efficacy highlighted by reduced tumor burden in MM.1S tumor-bearing mice compared to controls. On the basis of these findings, the rationale for CS1 targeting by human T cells armed with CS1-dbBiTE presents a potentially effective therapeutic approach for targeting MM.

Bendamustine lymphodepletion is a well-tolerated alternative to fludarabine and cyclophosphamide lymphodepletion for axicabtagene ciloleucel therapy for aggressive B-cell lymphoma

Fludarabine/cyclophosphamide (Flu/Cy) is established for lymphodepletion (LD) prior to standard-of-care CAR T-cell therapy for lymphoma. There is ongoing need to test alternative LD regimens to preserve efficacy, improve safety, and address challenges including the recent national fludarabine shortage. We retrospectively evaluated outcomes among patients with relapsed/refractory aggressive B-cell lymphoma who received bendamustine (n = 27) or Flu/Cy (n = 42) LD before axicabtagene ciloleucel (axi-cel) at our institution. The median change in absolute lymphocyte count from pre-LD to time of axi-cel infusion was -0.6×109 /L in bendamustine cohort and -0.7×109 /L in Flu/Cy cohort. The best overall response/complete response rates were 77.8% (95% CI: 57.7%-91.4%)/48.1% (95% CI: 28.7%-68.1%) among bendamustine cohort and 81.0% (95% CI: 65.9%-91.4%)/50.0% (95% CI: 34.2%-65.8%) among Flu/Cy cohort. Six-month progression-free survival were 43.8% (95% CI: 24.7%-61.3%) and 55.6% (95% CI: 39.0%-69.3%) in bendamustine and Flu/Cy cohorts, while 6-month overall survival were 81.5% (95% CI: 61.1%-91.8%) and 90.4% (95% CI: 76.4%-96.3%), respectively. Relative to Flu/Cy-treated patients, bendamustine-treated patients did not show an increase in hazards associated with experiencing progression/relapse/death (aHR:1.4 [95% CI: 0.7-2.8]; p = .32) or death (aHR:1.6 [95% CI: 0.5-5.6]; p = .46), after adjusting for baseline number of prior therapies and refractory disease. Any grade/grade ≥3 CRS were observed in 89%/3.7% and 86%/4.8% among bendamustine and Flu/Cy cohorts, while any grade ICANS/grade ≥3 ICANS were observed in 30%/19% and 55%/31% respectively. While more Flu/Cy-treated patients experienced grade ≥3 neutropenia compared with bendamustine-treated patients (100% vs. 68%), grade ≥3 infectious complications were comparable (24% vs. 19% respectively). More patients received bendamustine LD and axi-cel as outpatient than Flu/Cy cohort, without increased toxicities and with shorter median inpatient stays. In conclusion, we observed comparable efficacy and lower any grade ICANS among patients receiving bendamustine relative to Flu/Cy LD, followed by axi-cel.

Autologous Stem Cell Transplantation with Intensity Modulated Total Body Irradiation Conditioning for Systemic Sclerosis

PURPOSE/OBJECTIVE(S)

Based on the seminal SCOT trial, autologous stem cell transplantation (HSCT) using myeloablative total body irradiation (TBI) and anti-thymocyte globulin (ATG) as a conditioning regimen has become a standard treatment option for certain patients with systemic sclerosis (SSc). In patients with SSc, normal organs are more radiosensitive and prone to compromised function, and therefore lungs and kidneys require dose reduction. With traditional techniques, TBI requires heavy and thick physical blocks, which can be cumbersome and have poor reproducibility. We hypothesized that intensity modulated radiation therapy (IMRT) TBI compared to standard anteroposterior (AP)/posteroanterior (PA) TBI would facilitate improvements in dosimetry and reproducibility (due to not requiring physical blocks) without compromising outcomes. Herein, we report a single-institution retrospective analysis of patients with SSc treated with an IMRT TBI.

MATERIALS/METHODS

Patients with SSc who underwent HSCT with TBI between 2017 and 2022 were eligible. All patients underwent conditioning with equine ATG, cyclophosphamide 120 mg/kg, and IMRT TBI administered twice-daily to a total dose of 800 cGy in 200 cGy fractions. A minimum of 80% of the PTV was to receive prescription dose. Mean lung and kidney dose were to be less than 200 cGy. Patients were then replanned using an AP/PA technique for dosimetric comparison. The primary endpoint was planning target volume (PTV), lung, and kidney dosimetry. Secondary endpoints included event-free survival (EFS), overall survival (OS), disease-modifying antirheumatic drug-free survival (DMARD-FS), treatment related mortality (TRM), and toxicity.

RESULTS

A total of 14 patients were eligible for our analysis. On dosimetric analysis, the mean dose to the PTV was significantly higher on the IMRT compared to the AP/PA plans (809.4 cGy versus 728.5 cGy, p<0.001). The mean dose to the lungs (239.5 cGy versus 443.9 cGy, p<0.001) and kidneys (204.9 cGy versus 281.2 cGy, p<0.001) was significantly lower. Median follow-up was 34.6 months (1.0-51.7 months). There was one case of TRM secondary to respiratory failure. The 24-month OS, EFS, and DMARD-FS estimates were 92.9%, 74.3%, and 70.0%, respectively. Three patients experienced adverse events, which included respiratory failure (n = 1), renal failure (n = 1), and death (n = 1). No patients experienced clinically significant pneumonitis or nephritis that were deemed to be a likely consequence of TBI. Five patients subsequently initiated DMARDs, but three did so due to worsening skin symptoms without other major organ dysfunction.

CONCLUSION

Use of IMRT TBI as part of the conditioning regimen for HSCT for SSc yields improved dosimetry relative to a standard AP/PA technique, with efficacy and toxicity outcomes comparable with published data. This technique should be considered for patients undergoing HSCT for SSc and warrants inclusion in prospective trials for SSc that involve TBI.

Stimulation of Potent Humoral and Cellular Immunity via Synthetic Dual-Antigen MVA-Based COVID-19 Vaccine COH04S1 in Cancer Patients Post Hematopoietic Cell Transplantation and Cellular Therapy

Hematopoietic cell transplantation (HCT) and chimeric antigen receptor (CAR)-T cell patients are immunocompromised, remain at high risk following SARS-CoV-2 infection, and are less likely than immunocompetent individuals to respond to vaccination. As part of the safety lead-in portion of a phase 2 clinical trial in patients post HCT/CAR-T for hematological malignancies (HM), we tested the immunogenicity of the synthetic modified vaccinia Ankara-based COVID-19 vaccine COH04S1 co-expressing spike (S) and nucleocapsid (N) antigens. Thirteen patients were vaccinated 3-12 months post HCT/CAR-T with two to four doses of COH04S1. SARS-CoV-2 antigen-specific humoral and cellular immune responses, including neutralizing antibodies to ancestral virus and variants of concern (VOC), were measured up to six months post vaccination and compared to immune responses in historical cohorts of naïve healthy volunteers (HV) vaccinated with COH04S1 and naïve healthcare workers (HCW) vaccinated with the FDA-approved mRNA vaccine Comirnaty® (Pfizer, New York, NY, USA). After one or two COH04S1 vaccine doses, HCT/CAR-T recipients showed a significant increase in S- and N-specific binding antibody titers and neutralizing antibodies with potent activity against SARS-CoV-2 ancestral virus and VOC, including the highly immune evasive Omicron XBB.1.5 variant. Furthermore, vaccination with COH04S1 resulted in a significant increase in S- and N-specific T cells, predominantly CD4+ T lymphocytes. Elevated S- and N-specific immune responses continued to persist at six months post vaccination. Furthermore, both humoral and cellular immune responses in COH04S1-vaccinated HCT/CAR-T patients were superior or comparable to those measured in COH04S1-vaccinated HV or Comirnaty®-vaccinated HCW. These results demonstrate robust stimulation of SARS-CoV-2 S- and N-specific immune responses including cross-reactive neutralizing antibodies by COH04S1 in HM patients post HCT/CAR-T, supporting further testing of COH04S1 in immunocompromised populations.

Antigen-dependent IL-12 signaling in CAR T cells promotes regional to systemic disease targeting

Chimeric antigen receptor (CAR) T cell therapeutic responses are hampered by limited T cell trafficking, persistence, and durable anti-tumor activity in solid tumors. However, these challenges can be largely overcome by relatively unconstrained synthetic engineering strategies. Here, we describe CAR T cells targeting tumor-associated glycoprotein-72 (TAG72), utilizing the CD28 transmembrane domain upstream of the 4-1BB co-stimulatory domain as a driver of potent anti-tumor activity and IFNγ secretion. CAR T cell-mediated IFNγ production facilitated by IL-12 signaling is required for tumor cell killing, which is recapitulated by engineering an optimized membrane-bound IL-12 (mbIL12) molecule in CAR T cells. These T cells show improved antigen-dependent T cell proliferation and recursive tumor cell killing in vitro, with robust in vivo efficacy in human ovarian cancer xenograft models. Locoregional administration of mbIL12-engineered CAR T cells promotes durable anti-tumor responses against both regional and systemic disease in mice. Safety and efficacy of mbIL12-engineered CAR T cells is demonstrated using an immunocompetent mouse model, with beneficial effects on the immunosuppressive tumor microenvironment. Collectively, our study features a clinically-applicable strategy to improve the efficacy of locoregionally-delivered CAR T cells engineered with antigen-dependent immune-modulating cytokines in targeting regional and systemic disease.

Prediction of Coronary Heart Disease Events in Blood or Marrow Transplantation Recipients

Background

The long-term risk of coronary heart disease (CHD) and clinical models that predict this risk remain understudied in blood or marrow transplantation (BMT) recipients.

Objectives

This study sought to examine the risk of CHD after BMT and identify the associated risk factors.

Methods

Participants included patients transplanted between 1974 and 2014 at City of Hope, University of Minnesota, or University of Alabama at Birmingham and those who survived ≥2 years after BMT. Multivariable logistic regression models assessed CHD risk in BMT survivors compared with a sibling cohort. A self-reported questionnaire and medical records provided information regarding sociodemographics, comorbidities, and therapeutic exposures, which were used to develop a CHD risk prediction nomogram.

Results

Overall, 6,677 BMT recipients participated; the mean age at BMT was 43.9 ± 17.7 years, 58.3% were male, and 73.3% were non-Hispanic Whites. The median length of follow-up was 6.9 years (range: 2-46.2 years) from BMT. CHD was reported in 249 participants, with a 20-year cumulative incidence of 5.45% ± 0.39%. BMT survivors had a 1.6-fold greater odds of CHD compared with a sibling cohort (95% CI: 1.09-2.40). A nomogram was then developed to predict the risk of CHD at 10 and 20 years after BMT including age at BMT (HR: 1.06/y; 95% CI: 1.04-1.08), male sex (HR: 1.89; 95% CI: 1.15-3.11), a history of smoking (HR: 1.61; 95% CI: 1.01-2.58), diabetes (HR: 2.45; 95% CI: 1.23-4.89), hypertension (HR: 2.02; 95% CI: 1.15-3.54), arrhythmia (HR: 1.90; 95% CI: 0.89-4.06), and pre-BMT chest radiation (yes vs no: HR: 2.83; 95% CI: 1.20-6.67; unknown vs no: HR: 0.88; 95% CI: 0.34-2.28). The C-statistic was 0.77 in the test set (95% CI: 0.70-0.83).

Conclusions

This study identified BMT recipients at high risk for CHD, informing targeted screening for early detection and aggressive control of risk factors.

Tocilizumab for Cytokine Release Syndrome Management After Haploidentical Hematopoietic Cell Transplantation With Post-Transplantation Cyclophosphamide-Based Graft-Versus-Host Disease Prophylaxis

Cytokine release syndrome (CRS) is a common complication after haploidentical hematopoietic cell transplantation (HaploHCT). Severe CRS after haploHCT leads to higher risk of non-relapse mortality (NRM) and worse overall survival (OS). Tocilizumab (TOCI) is an interleukin-6 receptor inhibitor and is commonly used as first-line for CRS management after chimeric antigen receptor T cell therapy, but the impact of TOCI administration for CRS management on Haplo HCT outcomes is not known. In this single center retrospective analysis, we compared HCT outcomes in patients treated with or without TOCI for CRS management after HaploHCT with post-transplantation cyclophosphamide- (PTCy-) based graft-versus-host disease (GvHD) prophylaxis. Of the 115 patients eligible patients who underwent HaploHCT at City of Hope between 2019 to 2021 and developed CRS, we identified 11 patients who received tocilizumab for CRS management (TOCI). These patients were matched with 21 patients who developed CRS but did not receive tocilizumab (NO-TOCI) based on age at the time of HCT (≤64 years or >65 years or older), conditioning intensity (myeloablative versus reduced-intensity/nonmyeloablative), and CRS grading (1, 2, versus 3-4). Instead of 22 controls, we chose 21 patients because there was only 1 control matched with 1 TOCI treatment patient in 1 stratum. With only 11 patients in receiving tocilizumab for CRS treatment, matching with 21 patients who developed CRS but did not receive tocilizumab, we had 80% power to detect big differences (hazard ratio [HR] = 3.4 or higher) in transplantation outcomes using a 2-sided 0.05 test. The power would be reduced to about 20% to 30% if the difference was moderate (HR = 2.0) using the same test. No CRS-related deaths were recorded in either group. Median time to neutrophil engraftment was 21 days (range 16-43) in TOCI and 18 days (range 14-23) in NO-TOCI group (HR = 0.55; 95% confidence interval [CI] = 0.28-1.06, P = .08). Median time to platelet engraftment was 34 days (range 20-81) in TOCI and 28 days (range 12-94) in NO-TOCI group (HR = 0.56; 95% CI = 0.25-1.22, P = .19). Cumulative incidences of day 100 acute GvHD grades II-IV (P = .97) and grades III-IV (P = .47) were similar between the 2 groups. However, cumulative incidence of chronic GvHD at 1 year was significantly higher in patients receiving TOCI (64% versus 24%; P = .05). Rates of NRM (P = .66), relapse (P = .83), disease-free survival (P = .86), and overall survival (P = .73) were similar at 1 year after HCT between the 2 groups. Tocilizumab administration for CRS management after HaploHCT appears to be safe with no short-term adverse effect and no effect on relapse rate. However, the significantly higher cumulative incidence of chronic GvHD, negates the high efficacy of PTCy on GvHD prophylaxis in this patient population. Therefore using tocilizumab for CRS management in the HaploHCT population with PTCy maybe kept only for patients with severe CRS. The impact on such approach on long term outcome in HaploHCT with PTCy will need to be evaluated in a larger retrospective study or a prospective manner.

Risk of COVID-19 infection in long-term survivors of blood or marrow transplantation: a BMTSS report

There is limited information regarding COVID-19 in long-term blood or marrow transplant (BMT) survivors. We leveraged the BMT Survivor Study (BMTSS) to address this gap. BMTSS included patients who underwent BMT at 1 of 3 sites in the United States between 1974 and 2014 and survived ≥2 years after BMT. A sibling cohort serves as a non-BMT comparison group. Participants (2430 BMT survivors; 780 non-BMT participants) completed the BMTSS survey between October 2020 and November 2021 about COVID-19 testing, risk mitigation behaviors, morbidity, and health care use. Median age at BMT was 46 years (range, 0-78 years) and median follow-up since BMT was 14 years (6-46 years); 76% were non-Hispanic White, 54% had received allogeneic BMT. The risk of COVID-19 infection was comparable for BMT survivors vs non-BMT participants (15-month cumulative incidence, 6.5% vs 8.1%; adjusted odd ratio [aOR] = 0.93; 95% confidence interval [CI], 0.65-1.33; P = .68). Among survivors, being unemployed (aOR 1.90; 95% CI, 1.12-3.23; P = .02; reference: retired) increased the odds of infection; always wearing a mask in public was protective (aOR = 0.49; 95% CI, 0.31-0.77; P = .002; reference: not always masking). When compared with COVID-positive non-BMT participants, COVID-positive BMT survivors had higher odds of hospitalization (aOR = 2.23; 95% CI, 0.99-5.05; P = .05); however, the odds of emergency department visits were comparable (aOR = 1.60; 95% CI = 0.71-3.58; P = .25). COVID-19 infection status did not increase the odds of hospitalization among BMT survivors (aOR = 1.32; 95% CI = 0.89-1.95; P = .17) but did increase the odds of emergency department visits (aOR = 2.63; 95% CI, 1.74-3.98; P <.0001). These findings inform health care providers about the management of care for long-term BMT survivors during the ongoing pandemic.

Evaluation of the Elements of Short Hairpin RNAs in Developing shRNA-Containing CAR T Cells

Short hairpin RNAs (shRNAs) have emerged as a powerful tool for gene knockdown in various cellular systems, including chimeric antigen receptor (CAR) T cells. However, the elements of shRNAs that are crucial for their efficacy in developing shRNA-containing CAR T cells remain unclear. In this study, we evaluated the impact of different shRNA elements, including promoter strength, orientation, multiple shRNAs, self-targeting, and sense and antisense sequence composition on the knockdown efficiency of the target gene in CAR T cells. Our findings highlight the importance of considering multiple shRNAs and their orientation to achieve effective knockdown. Moreover, we demonstrate that using a strong promoter and avoiding self-targeting can enhance CAR T cell functionality. These results provide a framework for the rational design of CAR T cells with shRNA-mediated knockdown capabilities, which could improve the therapeutic efficacy of CAR T cell-based immunotherapy.

Feasibility of implementing a supervised telehealth exercise intervention in frail survivors of hematopoietic cell transplantation: a pilot randomized trial

BACKGROUND

Patients undergoing hematopoietic cell transplantation (HCT) are at high risk of chronic health complications, including frailty and physical dysfunction. Conventional exercise programs have been shown to improve frailty in other cancer populations, but these have largely been based out of rehabilitation facilities that may act as geographic and logistical barriers. There is a paucity of information on the feasibility of implementing telehealth exercise interventions in long-term HCT survivors.

METHODS

We conducted a pilot randomized trial to assess the feasibility of an 8-week telehealth exercise intervention in 20 pre-frail or frail HCT survivors. Participants were randomized to either a telehealth exercise (N = 10) or delayed control (N = 10). We administered a remote physical function assessment at baseline, followed by an 8-week telehealth exercise intervention (30-60 min/session, 3 sessions/week), and post-intervention. The primary endpoint was feasibility as determined by 1) > 70% of participants completing all remote physical functional assessments, and 2) > 70% of participants in the exercise group completing > 70% (17/24) of the prescribed exercise sessions. Exploratory outcomes included changes in gait speed, handgrip strength, and short physical performance battery.

RESULTS

The mean [standard deviation] age at study enrollment was 64.7 [9.1] years old. Twelve had undergone allogenic and 8 had undergone autologous HCT at an average of 17 years from study enrollment. Both feasibility criteria were achieved. Nineteen patients (95%) completed all remote study outcome assessments at baseline and post-intervention, and nine participants in the exercise group completed > 70% of prescribed exercise sessions. Overall, no significant group x time interaction was observed on handgrip strength, fatigue, body mass index, and short physical performance battery test (P < 0.05). However, there were significant within-group improvements in four-meter gait speed (+ 13.9%; P = 0.004) and 5-minute gait speed (+ 25.4%; P = 0.04) in the exercise group whereas non-significant changes in four-meter gait speed (-3.8%) and 5-minute gait speed (-5.8%) were observed after 8 weeks.

CONCLUSION

Implementing an 8-week telehealth exercise intervention for long-term HCT survivors was feasible. Our findings set the stage for innovative delivery of supervised exercise intervention that reduces the burden of frailty in HCT survivors as well as other at-risk cancer survivors.

TRIAL REGISTRATION

The protocol and informed consent were approved by the institutional IRB (IRB#20731) and registered (ClinicalTrials.gov NCT04968119; date of registration: 20/07/2021).

Intrinsic suppression of type I interferon production underlies the therapeutic efficacy of IL-15-producing natural killer cells in B-cell acute lymphoblastic leukemia

BACKGROUND

Type I interferons (IFN-Is), secreted by hematopoietic cells, drive immune surveillance of solid tumors. However, the mechanisms of suppression of IFN-I-driven immune responses in hematopoietic malignancies including B-cell acute lymphoblastic leukemia (B-ALL) are unknown.

METHODS

Using high-dimensional cytometry, we delineate the defects in IFN-I production and IFN-I-driven immune responses in high-grade primary human and mouse B-ALLs. We develop natural killer (NK) cells as therapies to counter the intrinsic suppression of IFN-I production in B-ALL.

RESULTS

We find that high expression of IFN-I signaling genes predicts favorable clinical outcome in patients with B-ALL, underscoring the importance of the IFN-I pathway in this malignancy. We show that human and mouse B-ALL microenvironments harbor an intrinsic defect in paracrine (plasmacytoid dendritic cell) and/or autocrine (B-cell) IFN-I production and IFN-I-driven immune responses. Reduced IFN-I production is sufficient for suppressing the immune system and promoting leukemia development in mice prone to MYC-driven B-ALL. Among anti-leukemia immune subsets, suppression of IFN-I production most markedly lowers the transcription of IL-15 and reduces NK-cell number and effector maturation in B-ALL microenvironments. Adoptive transfer of healthy NK cells significantly prolongs survival of overt ALL-bearing transgenic mice. Administration of IFN-Is to B-ALL-prone mice reduces leukemia progression and increases the frequencies of total NK and NK-cell effectors in circulation. Ex vivo treatment of malignant and non-malignant immune cells in primary mouse B-ALL microenvironments with IFN-Is fully restores proximal IFN-I signaling and partially restores IL-15 production. In B-ALL patients, the suppression of IL-15 is the most severe in difficult-to-treat subtypes with MYC overexpression. MYC overexpression promotes sensitivity of B-ALL to NK cell-mediated killing. To counter the suppressed IFN-I-induced IL-15 production in MYC^high human B-ALL, we CRISPRa-engineered a novel human NK-cell line that secretes IL-15. CRISPRa IL-15-secreting human NK cells kill high-grade human B-ALL in vitro and block leukemia progression in vivo more effectively than NK cells that do not produce IL-15.

CONCLUSION

We find that restoration of the intrinsically suppressed IFN-I production in B-ALL underlies the therapeutic efficacy of IL-15-producing NK cells and that such NK cells represent an attractive therapeutic solution for the problem of drugging MYC in high-grade B-ALL.

The impact of SARS-CoV2 vaccines on the incidence of graft versus host disease in allogeneic hematopoietic stem cell transplant recipients: a single-center retrospective study

This study reports the incidence of chronic graft versus host disease (GvHD) in allogeneic hematopoietic stem cell transplant (alloHCT) recipients who received SARS-CoV2 vaccination. The overall rates of new and worsening chronic GvHD combined were 14%, with median time from vaccination to GVHD being approximately three to four weeks. A majority of the cases were of mild to moderate severity and primarily localized to either the skin, mouth, or joints. Prior chronic GVHD and recent transplant were associated with higher GVHD rates following COVID-19 vaccination. More prospective studies are needed to provide a definitive mechanism for the impact of SARS-CoV2 vaccination on alloHCT patients.

Abstract 3235: Protein kinase C is an upstream regulator of IL13Ra2 and small molecular activator enhances CAR T mediated killing

Glioblastoma multiforme (GBM) is the most aggressive primary malignant brain cancer with a median survival of 16-20 months. Maximal safe resection and adjuvant chemotherapy improve survival but there is no cure and hence improved therapies are urgently needed. CAR T cell therapy has been FDA approved for hematologic malignancies but there are some barriers to their application for solid tumors in the clinic such as heterogenous tumor antigen expression. Chimeric Antigen Receptor (CAR) T Cells combine the cytolytic potency of T cells with the tumor specificity of an antibody. The interleukin 13 receptor alpha 2 (IL13Rα2) is an important target of CAR T cell therapy in ongoing GBM clinical trials. However, regulation of IL13Ra2 expression in GBM is unclear. Identifying upstream regulators of IL13Rα2 will not only help delineate IL13Rα2 carcinogenesis but also may help improve CAR T cell therapy. Utilizing knockout and overexpression constructs, we have identified protein kinase C family as an upstream regulator of IL13Rα2 transcription and translation in GBM cell lines. We have also identified a small molecule regulator of IL13Rα2, Ingenol-3-Angelate (I3A), that inhibits U87 tumor cell proliferation. Furthermore, I3A enhances IL13Rα2 re-directed CAR T cell mediated tumor cytolysis in vitro. Importantly, I3A treatment increases interferon gamma secretion by T cells. Taken together, our data implicates PKC isoforms as an upstream regulator of IL13Rα2. I3A treatment may serve as a therapeutic strategy to enhance CAR T mediated killing.

Citation Format: Siddharth Subham, John D. Jeppson, Bryan Schatmeyer, Stephen J. Forman, Christine E. Brown, David Akhavan. Protein kinase C is an upstream regulator of IL13Ra2 and small molecular activator enhances CAR T mediated killing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3235.

Association Between Pretreatment Skeletal Muscle and Outcomes After CAR T-Cell Therapy

BACKGROUND

The purpose of this study was to examine the association between baseline skeletal muscle measurements, acute toxicity (immune effector cell-associated neurotoxicity syndrome [ICANS], cytokine release syndrome), and treatment efficacy in patients undergoing CAR T-cell therapy for B-lineage lymphoma.

PATIENTS AND METHODS

Skeletal muscle measurements were obtained from automated CT measurements in 226 consecutive patients who received CAR T-cell therapy between 2015 and 2021. The Kaplan-Meier method was used to examine progression-free survival (PFS) and overall survival (OS) at 1-year. Multivariable regression was used to calculate the hazard ratio (HR) with 95% confidence intervals, adjusted for covariates.

RESULTS

The median age of the cohort was 63.1 years (range, 18.5-82.4 years), and most patients were male (66%) and had primary refractory disease (58%). Patients with abnormally low skeletal muscle at baseline were at greater risk of ICANS (HR, 1.74; 95% CI, 1.05-2.87) and had longer length of hospitalization (mean 27.7 vs 22.9 days; P<.05) compared with those with normal muscle mass. Abnormal skeletal muscle was independently associated with risk of disease progression (HR, 1.70; 95% CI, 1.11-2.57) and worse survival (HR, 2.44; 95% CI, 1.49-4.00) at 1 year compared with normal skeletal muscle. Individuals who had abnormal skeletal muscle and high lactate dehydrogenase (LDH) levels at baseline had poor 1-year PFS (17%) and OS (12%) compared with those with normal skeletal muscle and LDH levels (72% and 82%, respectively; P<.001). Patients who had abnormal skeletal muscle and LDH levels had a 5-fold risk (HR, 5.34; 95% CI, 2.97-9.62) of disease progression and a 10-fold risk (HR, 9.73; 95% CI, 4.81-19.70) of death (reference: normal skeletal muscle, normal LDH), independent of prior lines of therapy, extent of residual disease at time of CAR T-cell therapy, functional status, or product.

CONCLUSIONS

This information can be used for risk stratification prior to CAR T-cell therapy or to implement prehabilitation and nutritional optimization before lymphodepletion as well as thereafter. These efforts will be complementary to ongoing efforts toward sustained efficacy after CAR T-cell therapy.

Isoform-specific knockdown of long and intermediate prolactin receptors interferes with evolution of B-cell neoplasms

Prolactin (PRL) is elevated in B-cell-mediated lymphoproliferative diseases and promotes B-cell survival. Whether PRL or PRL receptors drive the evolution of B-cell malignancies is unknown. We measure changes in B cells after knocking down the pro-proliferative, anti-apoptotic long isoform of the PRL receptor (LFPRLR) in vivo in systemic lupus erythematosus (SLE)- and B-cell lymphoma-prone mouse models, and the long plus intermediate isoforms (LF/IFPRLR) in human B-cell malignancies. To knockdown LF/IFPRLRs without suppressing expression of the counteractive short PRLR isoforms (SFPRLRs), we employ splice-modulating DNA oligomers. In SLE-prone mice, LFPRLR knockdown reduces numbers and proliferation of pathogenic B-cell subsets and lowers the risk of B-cell transformation by downregulating expression of activation-induced cytidine deaminase. LFPRLR knockdown in lymphoma-prone mice reduces B-cell numbers and their expression of BCL2 and TCL1. In overt human B-cell malignancies, LF/IFPRLR knockdown reduces B-cell viability and their MYC and BCL2 expression. Unlike normal B cells, human B-cell malignancies secrete autocrine PRL and often express no SFPRLRs. Neutralization of secreted PRL reduces the viability of B-cell malignancies. Knockdown of LF/IFPRLR reduces the growth of human B-cell malignancies in vitro and in vivo. Thus, LF/IFPRLR knockdown is a highly specific approach to block the evolution of B-cell neoplasms.

High response rates and transition to transplant after novel targeted and cellular therapies in adults with relapsed/refractory acute lymphoblastic leukemia with Philadelphia-like fusions

Philadelphia (Ph)-like acute lymphoblastic leukemia (ALL) is associated with a poor response to standard chemotherapy. However, outcomes with novel antibody and cellular therapies in relapsed/refractory (r/r) Ph-like ALL are largely unknown. We conducted a single-center retrospective analysis of adult patients (n = 96) with r/r B-ALL and fusions associated with Ph-like who received novel salvage therapies. Patients were treated with 149 individual novel regimens (blinatumomab = 83, inotuzumab ozogamicin [InO] = 36, and CD19CAR T cells = 30). The median age at first novel salvage therapy was 36 years (range; 18-71). Ph-like fusions were IGH::CRLF2 (n = 48), P2RY8::CRLF2 (n = 26), JAK2 (n = 9), ABL-class (n = 8), EPOR::IGH (n = 4) and ETV6::NTRK2 (n = 1). CD19CAR T cells were administered later in the course of therapy compared to blinatumomab and InO (p < .001) and more frequently in recipients who relapsed after allogeneic hematopoietic cell transplantation (alloHCT) (p = .002). Blinatumomab was administered at an older age compared to InO and CAR T-cells (p = .004). The complete remission (CR)/CR with incomplete hematologic recovery (CRi) rates were 63%, 72%, and 90% following blinatumomab, InO and CD19CAR, respectively, among which 50%, 50%, and 44% of responders underwent consolidation with alloHCT, respectively. In multivariable analysis, the type of novel therapy (p = .044) and pretreatment marrow blasts (p = .006) predicted the CR/CRi rate, while the Ph-like fusion subtype (p = .016), pretreatment marrow blasts (p = .022) and post-response consolidation with alloHCT (p < .001) influenced event-free survival. In conclusion, novel therapies are effective in inducing high remission rates in patients with r/r Ph-like ALL and successfully transitioning the responders to alloHCT.

Functional SARS-CoV-2-specific T cells of donor origin in allogeneic stem cell transplant recipients of a T-cell-replete infusion: A prospective observational study

In the current post-pandemic era, recipients of an allogeneic hematopoietic stem cell transplant (HCT) deserve special attention. In these vulnerable patients, vaccine effectiveness is reduced by post-transplant immune-suppressive therapy; consequently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) is often associated with elevated morbidity and mortality. Characterizing SARS-CoV-2 adaptive immunity transfer from immune donors to HCT recipients in the context of immunosuppression will help identify optimal timing and vaccination strategies that can provide adequate protection to HCT recipients against infection with evolving SARS-CoV-2 variants. We performed a prospective observational study (NCT04666025 at ClinicalTrials.gov) to longitudinally monitor the transfer of SARS-CoV-2-specific antiviral immunity from HCT donors, who were either vaccinated or had a history of COVID-19, to their recipients via T-cell replete graft. Levels, function, and quality of SARS-CoV-2-specific immune responses were longitudinally analyzed up to 6 months post-HCT in 14 matched unrelated donor/recipients and four haploidentical donor/recipient pairs. A markedly skewed donor-derived SARS-CoV-2 CD4 T-cell response was measurable in 15 (83%) recipients. It showed a polarized Th1 functional profile, with the prevalence of central memory phenotype subsets. SARS-CoV-2-specific IFN-γ was detectable throughout the observation period, including early post-transplant (day +30). Functionally experienced SARS-CoV-2 Th1-type T cells promptly expanded in two recipients at the time of post-HCT vaccination and in two others who were infected and survived post-transplant COVID-19 infection. Our data suggest that donor-derived SARS-CoV-2 T-cell responses are functional in immunosuppressed recipients and may play a critical role in post-HCT vaccine response and protection from the fatal disease.

Clinical trial registration

clinicaltrials.gov, identifier NCT04666025.

Malignant Neoplasms of the Gastrointestinal Tract After Blood or Marrow Transplant

Importance

Survivors of blood or marrow transplant (BMT) are at increased risk of subsequent malignant neoplasms (SMNs). Cancers of the gastrointestinal (GI) system are of special interest because their clinical behavior is often aggressive, necessitating early detection by increasing awareness of high-risk populations.

Objective

To describe the risk of SMNs in the GI tract after BMT.

Design, Setting, and Participants

A cohort study of 6710 individuals who lived at least 2 years after BMT performed between January 1, 1974, and December 31, 2014, at City of Hope, University of Minnesota, or University of Alabama at Birmingham. End of follow-up was March 23, 2020. Data analysis was performed between September 1, 2022, and September 30, 2022.

Exposures

Demographic and clinical factors; therapeutic exposures before or as part of BMT.

Main Outcomes and Measures

Development of SMNs in the GI tract after BMT. Participants self-reported SMNs in the GI tract; these were confirmed with pathology reports, medical records, or both. For deceased patients, death records were used. Standardized incidence ratios determined excess risk of SMNs in the GI tract compared with that of the general population. Fine-Gray proportional subdistribution hazard models assessed the association between risk factors and SMNs in the GI tract.

Results

The cohort of 6710 individuals included 3444 (51.3%) autologous and 3266 (48.7%) allogeneic BMT recipients. A total of 3917 individuals (58.4%) were male, and the median age at BMT was 46 years (range, 0-78 years). After 62 479 person-years of follow-up, 148 patients developed SMNs in the GI tract. The standardized incidence ratios for developing specific SMNs ranged from 2.1 for colorectal cancer (95% CI, 1.6-2.8; P < .001) to 7.8 for esophageal cancer (95% CI, 5.0-11.6; P < .001). Exposure to cytarabine for conditioning (subdistribution hazard ratio [SHR], 3.1; 95% CI, 1.5-6.6) was associated with subsequent colorectal cancer. Compared with autologous BMT recipients, allogeneic BMT recipients with chronic graft-vs-host disease were at increased risk for esophageal cancer (SHR, 9.9; 95% CI, 3.2-30.5). Conditioning with etoposide (SHR, 2.0; 95% CI, 1.1-3.5) and pre-BMT anthracycline exposure (SHR, 5.4; 95% CI, 1.3-23.4) were associated with an increased risk of liver cancer compared with no exposure to the respective agents.

Conclusions and Relevance

The findings of this cohort study are relevant for oncologists and nononcologists who care for the growing number of survivors of transplant. Awareness of subgroups of survivors of BMT at high risk for specific types of SMNs in the GI tract may influence recommendations regarding modifiable risk factors, as well as individualized screening.

Favorable Activity and Safety Profile of Memory-Enriched CD19-Targeted Chimeric Antigen Receptor T-Cell Therapy in Adults with High-Risk Relapsed/Refractory ALL

PURPOSE

A phase I/II study evaluating the safety and activity of memory-enriched CD19-directed chimeric antigen receptor (CD19-CAR) T cells in adults with relapsed/refractory B-cell acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

In phase I, we tested sequentially two cell populations for CAR transduction: (i) central memory (Tcm) or (ii) naïve, stem, and central memory (Tn/mem) T cells. The study employed an activity constrained for toxicity design to determine the recommended phase II dose (RP2D), which was tested in phase II.

RESULTS

The Tcm cohort was closed early due to lack of activity. The 200 ×106 Tn/mem-derived CD19-CAR T-cell dose was found to be safe and active, and was declared the RP2D. At RP2D, 58 participants underwent leukapheresis and 46 received CD19-CAR T cells. Median age for treated participants was 38 years (range, 22-72). Twenty-nine (63%) participants had relapsed post-allogeneic hematopoietic cell transplantation (alloHCT), 18 (39%) had Philadelphia-like (Ph-like) genotype, and 16 (35%) had extramedullary disease (EMD) at lymphodepletion (LD). Three (7%) participants had grade 3 cytokine release syndrome (CRS), and none had grade ≥ 4 CRS. Eight (17%) participants had grade ≥ 3 neurotoxicity, including one fatal cerebral edema. Forty (87%) patients achieved complete remission (CR)/CR with incomplete hematologic recovery, 2 (4%) progressed, and 4 (9%) were unevaluable for response. Among 42 response-evaluable participants, 16/17 with Ph-like ALL and 13/15 with EMD at LD responded. Twenty-one (53%) responders underwent alloHCT consolidation, which was associated with improved relapse-free survival (adjusted HR = 0.16; 95% confidence interval, 0.05-0.48; P = 0.001).

CONCLUSIONS

Tn/mem-derived CD19-CAR T cells were safe and active, including in Ph-like ALL and EMD. See related commentary by El Marabti and Abdel-Wahab, p. 694.

Financial Burden in Blood or Marrow Transplantation Survivors During the COVID-19 Pandemic: A BMTSS Report

PURPOSE

The financial burden experienced by blood or marrow transplant (BMT) survivors during the COVID-19 pandemic remains unstudied. We evaluated the risk for high out-of-pocket medical costs and associated financial burden experienced by BMT survivors and a sibling comparison group during the COVID-19 pandemic.

METHODS

This study included 2,370 BMT survivors and 750 siblings who completed the BMT Survivor Study survey during the pandemic. Participants reported employment status, out-of-pocket medical costs, and financial burden. Medical expenses ≥ 10% of the annual household income constituted high out-of-pocket medical costs. Logistic regression identified factors associated with high out-of-pocket medical costs and financial burden.

RESULTS

BMT survivors were more likely to incur high out-of-pocket medical costs (11.3% v 3.1%; adjusted odds ratio [aOR], 2.88; 95% CI, 1.84 to 4.50) than the siblings. Survivor characteristics associated with high out-of-pocket medical costs included younger age at study (aORper_year_younger_age, 1.02; 95% CI, 1.00 to 1.03), lower prepandemic annual household income and/or education (< $50,000 US dollars and/or < college graduate: aOR, 1.96; 95% CI, 1.42 to 2.69; reference: ≥ $50,000 in US dollars and ≥ college graduate), > 1 chronic health condition (aOR, 2.82; 95% CI, 2.00 to 3.98), ≥ 1 hospitalization during the pandemic (aOR, 2.11; 95% CI, 1.53 to 2.89), and being unemployed during the pandemic (aOR, 1.52; 95% CI, 1.06 to 2.17). Among BMT survivors, high out-of-pocket medical costs were significantly associated with problems in paying medical bills (aOR, 10.57; 95% CI, 7.39 to 15.11), deferring medical care (aOR, 4.93; 95% CI, 3.71 to 6.55), taking a smaller dose of medication than prescribed (aOR, 4.99; 95% CI, 3.23 to 7.70), and considering filing for bankruptcy (aOR, 3.80; 95% CI, 2.14 to 6.73).

CONCLUSION

BMT survivors report high out-of-pocket medical costs, which jeopardizes their health care and may affect health outcomes. Policies aimed at reducing financial burden in BMT survivors, such as expanding access to patient assistance programs, may mitigate the negative health consequences.

Potentially inappropriate medications in geriatric blood or marrow transplantation (BMT) survivors: A BMT Survivor Study report

BACKGROUND

Blood or marrow transplantation (BMT) is increasingly offered to older individuals with hematologic malignancies. The high prevalence of chronic health conditions in such individuals necessitates use of multiple medications. Beers Criteria represent a list of potentially inappropriate medications (PIMs) shown to increase the risk of health problems in the elderly. We sought to determine the prevalence and predictors of PIM use in older BMT survivors and identify associations with health problems.

METHODS

Study participants were drawn from the BMT Survivor Study, a cohort study of patients transplanted at three US transplant centers between 1974 and 2014 and surviving ≥2 years. For this report, the survivors were aged ≥65 years. Siblings served as a comparison group. Participants self-reported sociodemographics, chronic health conditions, and medication use. Logistic regression analyses identified predictors of PIM use and associations with health problems.

RESULTS

Overall, PIM use was comparable between BMT survivors (49.4%) and siblings (49.3%) (odds ratio [OR] = 0.9; 95% CI, 0.7-1.2); however, BMT survivors were more likely to use >1 PIM (17.4% vs. 12.4%; OR = 1.5; 95% CI, 1.01-2.4) and central nervous system-related PIMs (8.3% vs. 4.3%; OR = 2.18; 95% CI, 1.17-4.09). Predictors of PIM use included presence of severe/life-threatening chronic health conditions (OR = 1.5; 95% CI, 1.1-2.0), and chronic graft versus host disease (OR = 1.7; 95% CI, 1.1-2.7). Survivors taking >1 PIM reported more issues with vertigo (OR = 2.3; 95% CI, 1.1-4.7), balance (OR = 2.6; 95% CI, 1.7-4.1), faintness/dizziness (OR = 2.8; 95% CI, 1.8-4.6), and personal care (OR = 4.5; 95% CI, 1.4-14.8).

CONCLUSIONS

This study shows the health problems associated with PIM use and identifies vulnerable populations at higher risk for PIM use, providing evidence for caution in using PIMs in high-risk populations.

Post-Transplantation Sinusoidal Obstruction Syndrome in Adult Patients with B Cell Acute Lymphoblastic Leukemia Treated with Pretransplantation Inotuzumab

Sinusoidal obstruction syndrome (SOS) is a potentially life-threatening complication that can be observed after allogeneic hematopoietic cell transplantation (HCT). Inotuzumab ozogamicin is an anti-CD22 monoclonal antibody-drug conjugate that has demonstrated high efficacy in relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) but is associated with an increased risk of SOS in HCT recipients. Here we aimed to examine the incidence and outcomes of SOS in 47 adult patients with R/R ALL who received inotuzumab therapy and subsequently underwent HCT at our institution. All patients received prophylactic therapy with ursodiol, and continuous low-dose heparin also was administered to patients receiving myeloablative conditioning (MAC). SOS occurred in 12 patients (26%) post-HCT, at a median onset of 11 days (range, 3 to 41 days). SOS was graded as very severe in 50% (n = 6), severe in 25% (n = 3), and mild in 25% (n = 3). All patients diagnosed with SOS received treatment with defibrotide for a median of 21 days (range, 3 to 34 days), with resolution of SOS occurring in 8 patients (67%). Mortality from SOS was 33% (n = 4) and occurred at a median of 10 days from diagnosis (range, 3 to 31 days) in patients graded as very severe (n = 3) or severe (n = 1). There were no significant differences between patients who developed SOS and those who did not develop SOS in the median time from the last dose of inotuzumab to transplantation (46 days versus 53 days; P = .37), use of an MAC regimen (42% versus 49%; P = .75), number of lines of therapy prior to inotuzumab (P = .79), median number of administered cycles of inotuzumab (2 versus 2; P = .14), or receipt of inotuzumab as the last therapy prior to HCT (67% versus 66%; P = 1.0). Sirolimus-based graft-versus-host disease (GVHD) prophylaxis was used more frequently in the SOS group (75% versus 29%; P < .01), but there was no between-group difference in the peak sirolimus level (P = .81) or the median time to peak sirolimus level (7 days versus 3.5 days; P = .39). In univariable analysis, only the use of sirolimus-based GVHD prophylaxis was significantly associated with an increased risk of SOS (hazard ratio [HR], 7.50; 95% confidence interval [CI], 1.7 to 33.6; P < .01). In the SOS group, the 100-day mortality rate was 33% (n = 4), and median overall survival (OS) post-HCT was 4.3 months (range, 0.2 to 57.2 months). In the group without SOS, the 100-day mortality rate was 14% (n = 5) and the median OS post-HCT was 10.7 months (range, .52 to 39.6 months). In this study cohort, SOS was prevalent in HCT recipients who had been treated with inotuzumab prior to transplantation, and sirolimus-based GVHD prophylaxis was a risk factor for SOS in inotuzumab recipients.

Antigen-dependent IL-12 signaling in CAR T cells promotes regional to systemic disease targeting

Chimeric antigen receptor (CAR) T cell therapeutic responses are hampered by limited T cell trafficking, persistence, and durable anti-tumor activity in solid tumor microenvironments. However, these challenges can be largely overcome by relatively unconstrained synthetic engineering strategies, which are being harnessed to improve solid tumor CAR T cell therapies. Here, we describe fully optimized CAR T cells targeting tumor-associated glycoprotein-72 (TAG72) for the treatment of solid tumors, identifying the CD28 transmembrane domain upstream of the 4-1BB co-stimulatory domain as a driver of potent anti-tumor activity and IFNγ secretion. These findings have culminated into a phase 1 trial evaluating safety, feasibility, and bioactivity of TAG72-CAR T cells for the treatment of patients with advanced ovarian cancer ( NCT05225363 ). Preclinically, we found that CAR T cell-mediated IFNγ production facilitated by IL-12 signaling was required for tumor cell killing, which was recapitulated by expressing an optimized membrane-bound IL-12 (mbIL12) molecule on CAR T cells. Critically, mbIL12 cell surface expression and downstream signaling was induced and sustained only following CAR T cell activation. CAR T cells with mbIL12 demonstrated improved antigen-dependent T cell proliferation and potent cytotoxicity in recursive tumor cell killing assays in vitro and showed robust in vivo anti-tumor efficacy in human xenograft models of ovarian cancer peritoneal metastasis. Further, locoregional administration of TAG72-CAR T cells with antigen-dependent IL-12 signaling promoted durable anti-tumor responses against both regional and systemic disease in mice and was associated with improved systemic T cell persistence. Our study features a clinically-applicable strategy to improve the overall efficacy of locoregionally-delivered CAR T cells engineered with antigen-dependent immune-modulating cytokines in targeting both regional and systemic disease.

Inclusion of 4-1BB Costimulation Enhances Selectivity and Functionality of IL13Rα2-Targeted Chimeric Antigen Receptor T Cells

Chimeric antigen receptor (CAR) T cell immunotherapy is emerging as a powerful strategy for cancer therapy; however, an important safety consideration is the potential for off-tumor recognition of normal tissue. This is particularly important as ligand-based CARs are optimized for clinical translation. Our group has developed and clinically translated an IL13(E12Y) ligand-based CAR targeting the cancer antigen IL13Rα2 for treatment of glioblastoma (GBM). There remains limited understanding of how IL13-ligand CAR design impacts the activity and selectivity for the intended tumor-associated target IL13Rα2 versus the more ubiquitous unintended target IL13Rα1. In this study, we functionally compared IL13(E12Y)-CARs incorporating different intracellular signaling domains, including first-generation CD3ζ-containing CARs (IL13ζ), second-generation 4-1BB (CD137)-containing or CD28-containing CARs (IL13-BBζ or IL13-28ζ), and third-generation CARs containing both 4-1BB and CD28 (IL13-28BBζ). In vitro coculture assays at high tumor burden establish that second-generation IL13-BBζ or IL13-28ζ outperform first-generation IL13ζ and third-generation IL13-28BBζ CAR designs, with IL13-BBζ providing superior CAR proliferation and in vivo antitumor potency in human xenograft mouse models. IL13-28ζ displayed a lower threshold for antigen recognition, resulting in higher off-target IL13Rα1 reactivity both in vitro and in vivo. Syngeneic mouse models of GBM also demonstrate safety and antitumor potency of murine IL13-BBζ CAR T cells delivered systemically after lymphodepletion. These findings support the use of IL13-BBζ CARs for greater selective recognition of IL13Rα2 over IL13Rα1, higher proliferative potential, and superior antitumor responsiveness. This study exemplifies the potential of modulating factors outside the antigen targeting domain of a CAR to improve selective tumor recognition.

Significance

This study reveals how modulating CAR design outside the antigen targeting domain improves selective tumor recognition. Specifically, this work shows improved specificity, persistence, and efficacy of 4-1BB-based IL13-ligand CARs. Human clinical trials evaluating IL13-41BB-CAR T cells are ongoing, supporting the clinical significance of these findings.

Brentuximab vedotin plus nivolumab after autologous haematopoietic stem-cell transplantation for adult patients with high-risk classic Hodgkin lymphoma: a multicentre, phase 2 trial

BACKGROUND

After autologous haematopoietic stem-cell transplantation (HSCT), consolidation with brentuximab vedotin in patients with high-risk relapsed or refractory classic Hodgkin lymphoma has been shown to improve progression-free survival compared with placebo. Brentuximab vedotin plus nivolumab is a safe and effective treatment for relapsed or refractory classic Hodgkin lymphoma; therefore, we aimed to evaluate the safety and activity of this drug combination post-autologous HSCT consolidation in patients with high-risk relapsed or refractory classic Hodgkin lymphoma.

METHODS

We did a multicentre phase 2 trial at five centres in the USA. Eligible patients were aged 18 years or older with high-risk relapsed or refractory classic Hodgkin lymphoma, had an ECOG performance status of 0-2, and had adequate organ and bone marrow function. Enrolled patients received brentuximab vedotin (1·8 mg/kg) and nivolumab (3 mg/kg) intravenously starting 30-60 days after autologous HSCT on day 1 of each 21-day cycle for up to 8 cycles. Nivolumab dose reduction was not allowed. Brentuximab vedotin dose reduction to 1·2 mg/kg was permitted. If one drug was discontinued because of a toxic effect, the other could be continued. The primary endpoint was 18-month progression-free survival in all treated patients. This study is registered with ClinicalTrials.gov, number NCT03057795.

FINDINGS

Between May 3, 2017, and July 13, 2019, 59 patients were enrolled and received the study therapy. Patients initiated brentuximab vedotin plus nivolumab for a median of 54 days (IQR 46-58) after autologous HSCT and received a median of 8 cycles (8-8). 34 (58%) of 59 patients were male, 29 (49%) completed 8 cycles of brentuximab vedotin plus nivolumab, and 45 (76%) completed 8 cycles of at least one drug. The median follow-up time was 29·9 months (IQR 24·6-34·8). The 18-month progression-free survival in all 59 patients was 94% (95% CI 84-98). The most common adverse events were sensory peripheral neuropathy (31 [53%] of 59) and neutropenia (25 [42%]), and immune-related adverse events requiring corticosteroids occurred in 17 (29%) of 59 patients. No treatment-related deaths were observed.

INTERPRETATION

Brentuximab vedotin plus nivolumab was highly active post-autologous HSCT consolidation for patients with high-risk relapsed or refractory classic Hodgkin lymphoma, most of whom had previous exposure to either brentuximab vedotin or PD-1 blockade. Combination immunotherapy in this setting should be further studied in patients with classic Hodgkin lymphoma with further refinement of the regimen to mitigate toxic effects, particularly in high-risk patients in whom more intensive therapy to prevent relapse is warranted.

FUNDING

Bristol Myers Squibb, Leukemia and Lymphoma Society, Lymphoma Research Foundation, and National Cancer Institute of the National Institutes of Health.

Cost-effectiveness of polatuzumab vedotin combined with chemoimmunotherapy in untreated diffuse large B-cell lymphoma

In patients with treatment-naive diffuse large B-cell lymphoma (DLBCL), the POLARIX study (A Study Comparing the Efficacy and Safety of Polatuzumab Vedotin With Rituximab-Cyclophosphamide, Doxorubicin, and Prednisone [R-CHP] Versus Rituximab-Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone [R-CHOP] in Participants With Diffuse Large B-Cell Lymphoma) reported a 6.5% improvement in the 2-year progression-free survival (PFS), with no difference in overall survival (OS) or safety using polatuzumab vedotin, rituximab, cyclophosphamide, doxorubicin, and prednisone (pola-R-CHP) compared with standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). We evaluated the cost-effectiveness of pola-R-CHP for DLBCL. We modeled a hypothetical cohort of US adults (mean age, 65 years) with treatment-naive DLBCL by developing a Markov model (lifetime horizon) to model the cost-effectiveness of pola-R-CHP and R-CHOP using a range of plausible long-term outcomes. Progression rates and OS were estimated from POLARIX. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay (WTP) threshold of $150 000 per quality-adjusted life-year (QALY). Assuming a 5-year PFS of 69.6% with pola-R-CHP and 62.7% with R-CHOP, pola-R-CHP was cost-effective at a WTP of $150 000 (incremental cost-effectiveness ratio, $84 308/QALY). pola-R-CHP was no longer cost-effective if its 5-year PFS was 66.1% or lower. One-way sensitivity analysis revealed that pola-R-CHP is cost-effective up to a cost of $276 312 at a WTP of $150 000. pola-R-CHP was the cost-effective strategy in 56.6% of the 10 000 Monte Carlo iterations at a WTP of $150 000. If the absolute benefit in PFS is maintained over time, pola-R-CHP is cost-effective compared with R-CHOP at a WTP of $150 000/QALY. However, its cost-effectiveness is highly dependent on its long-term outcomes and costs of chimeric antigen receptor T-cell therapy. Routine usage of pola-R-CHP would add significantly to health care expenditures. Price reductions or identification of subgroups that have maximal benefit would improve cost-effectiveness.