Multicenter development of a PET-based risk assessment tool for product-specific outcome prediction in large B-cell lymphoma patients undergoing CAR T-cell therapy

PURPOSE

The emergence of chimeric antigen receptor (CAR) T-cell therapy fundamentally changed the management of individuals with relapsed and refractory large B-cell lymphoma (LBCL). However, real-world data have shown divergent outcomes for the approved products. The present study therefore set out to evaluate potential risk factors in a larger cohort.

METHODS

Our analysis set included 88 patients, treated in four German university hospitals and one Italian center, who had undergone 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (PET) before CAR T-cell therapy with tisagenlecleucel or axicabtagene ciloleucel. We first determined the predictive value of conventional risk factors, treatment lines, and response to bridging therapy for progression-free survival (PFS) through forward selection based on Cox regression. In a second step, the additive potential of two common PET parameters was assessed. Their optimal dichotomizing thresholds were calculated individually for each CAR T-cell product.

RESULTS

Extra-nodal involvement emerged as the most relevant of the conventional tumor and patient characteristics. Moreover, we found that inclusion of metabolic tumor volume (MTV) further improves outcome prediction. The hazard ratio for a PFS event was 1.68 per unit increase of our proposed risk score (95% confidence interval [1.20, 2.35], P = 0.003), which comprised both extra-nodal disease and lymphoma burden. While the most suitable MTV cut-off among patients receiving tisagenlecleucel was 11 mL, a markedly higher threshold of 259 mL showed optimal predictive performance in those undergoing axicabtagene ciloleucel treatment.

CONCLUSION

Our analysis demonstrates that the presence of more than one extra-nodal lesion and higher MTV in LBCL are associated with inferior outcome after CAR T-cell treatment. Based on an assessment tool including these two factors, patients can be assigned to one of three risk groups. Importantly, as shown by our study, metabolic tumor burden might facilitate CAR T-cell product selection and reflect the individual need for bridging therapy.

Recent Bendamustine Treatment Before Apheresis Has a Negative Impact on Outcomes in Patients With Large B-Cell Lymphoma Receiving Chimeric Antigen Receptor T-Cell Therapy

PURPOSE

Approximately 30%-40% of patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) infused with CD19-targeted chimeric antigen receptor (CAR) T cells achieve durable responses. Consensus guidelines suggest avoiding bendamustine before apheresis, but specific data in this setting are lacking. We report distinct outcomes after CAR T-cell therapy according to previous bendamustine exposure.

METHODS

The study included CAR T-cell recipients from seven European sites. Safety, efficacy, and CAR T-cell expansion kinetics were analyzed according to preapheresis bendamustine exposure. Additional studies on the impact of the washout period and bendamustine dose were performed. Inverse probability treatment weighting (IPTW) and propensity score matching (PSM) analyses were carried out for all efficacy comparisons between bendamustine-exposed and bendamustine-naïve patients.

RESULTS

The study included 439 patients with R/R LBCL infused with CD19-targeted commercial CAR T cells, of whom 80 had received bendamustine before apheresis. Exposed patients had significantly lower CD3+ cells and platelets at apheresis. These patients had a lower overall response rate (ORR, 53% v 72%; P < .01), a shorter progression-free survival (PFS, 3.1 v 6.2 months; P = .04), and overall survival (OS, 10.3 v 23.5 months; P = .01) in comparison with the bendamustine-naïve group. Following adjustment methods for baseline variables, these differences were mitigated. Focusing on the impact of bendamustine washout before apheresis, those with recent (<9 months) exposure (N = 42) displayed a lower ORR (40% v 72%; P < .01), shorter PFS (1.3 v 6.2 months; P < .01), and OS (4.6 v 23.5 months; P < .01) in comparison with bendamustine-naïve patients. These differences remained significant after IPTW and PSM analysis. Conversely, the cumulative dose of bendamustine before apheresis did not affect CAR-T efficacy outcomes.

CONCLUSION

Recent bendamustine exposure before apheresis was associated with negative treatment outcomes after CD19-targeted CAR T-cell therapy and should be therefore avoided in CAR T-cell candidates.

Predictive value of pre-infusion tumor growth rate for the occurrence and severity of CRS and ICANS in lymphoma under CAR T-cell therapy

Chimeric antigen receptor T-cell therapy (CART) can be administered outpatient yet requires management of potential side effects such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The pre-infusion tumor burden is associated with CRS, yet there is no data on the relevance of pre-infusion tumor growth rate (TGR). Our objective was to investigate TGR for the occurrence and severity of CRS and ICANS. Consecutive patients with available pre-baseline and baseline (BL) imaging before CART were included. TGR was determined as both absolute (abs) and percentage change (%) of Lugano criteria-based tumor burden in relation to days between exams. CRS and ICANS were graded according to ASTCT consensus criteria. Clinical metadata was collected including the international prognostic index (IPI), patient age, ECOG performance status, and LDH. Sixty-two patients were included (median age: 62 years, 40% female). The median pre-BL TGR [abs] and pre-BL TGR [%] was 7.5 mm2/d and 30.9%/d. Pre-BL TGR [abs] and pre-BL TGR [%] displayed a very weak positive correlation with the grade of CRS (r[abs] = 0.14 and r[%] = 0.13) and no correlation with ICANS (r[abs] =  - 0.06 and r[%] =  - 0.07). There was a weak positive correlation between grade of CRS and grade of ICANS (r = 0.35; p = 0.005) whereas there was no significant correlation of CRS or ICANS to any other of the examined parameters. The pre-infusion TGR before CART was weakly associated with the occurrence of CRS, but not the severity, whereas there were no significant differences in the prediction of ICANS. There was no added information when compared to pre-infusion tumor burden alone. Outpatient planning and toxicity management should not be influenced by the pre-infusion TGR.

Modification of Lugano criteria by pre-infusion tumor kinetics improves early survival prediction for patients with lymphoma under chimeric antigen receptor T-cell therapy

BACKGROUND

Chimeric antigen receptor T-cell therapy (CART) is effective for patients with refractory or relapsed lymphoma with prolongation of survival. We aimed to improve the prediction of Lugano criteria for overall survival (OS) at 30-day follow-up (FU1) by including the pre-infusion tumor growth rate (TGRpre-BL) and its early change to 30-day FU1 imaging (TGRpost-BL).

METHODS

Consecutive patients with pre-baseline (pre-BL), baseline (BL) and FU1 imaging with CT or positron emission tomography/CT before CART were included. TGR was defined as change of Lugano criteria-based tumor burden between pre-BL, BL and FU1 examinations in relation to days between imaging examinations. Overall response and progression-free survival were determined based on Lugano criteria. Proportional Cox regression analysis studied association of TGR with OS. For survival analysis, OS was analyzed using Kaplan-Meier survival curves.

RESULTS

Fifty-nine out of 81 patients met the inclusion criteria. At 30-day FU1 8 patients (13.6%) had a complete response (CR), 25 patients (42.4%) a partial response (PR), 15 patients (25.4%) a stable disease (SD), and 11 patients (18.6%) a progressive disease (PD) according to CT-based Lugano criteria. The median TGRpre-BL was -0.6 mm2/day, 24.4 mm2/day, -5.1 mm2/day, and 18.6 mm2/day and the median TGRpost-BL was -16.7 mm2/day, -102.0 mm2/day, -19.8 mm2/day and 8.5 mm2/day in CR, PR, SD, and PD patients, respectively. PD patients could be subclassified into a cohort with an increase in TGR (7 of 11 patients (64%), PD TGRpre-to-post-BL INCR) and a cohort with a decrease in TGR (4 of 11 patients (36%), PD TGRpre-to-post-BL DECR) from pre-BL to post-BL. PD TGRpre-to-post-BL DECR patients exhibited similar OS to patients classified as SD, while PD TGRpre-to-post-BL INCR patients had significantly shorter OS (65 days vs 471 days, p<0.001).

CONCLUSION

In the context of CART, the additional use of TGRpre-BL and its change to TGRpost-BL determined at 30-day FU1 showed better OS prognostication for patients with overall PD according to Lugano criteria. Therefore, this modification of the Lugano classification should be explored as a potential novel imaging biomarker of early response and should be validated prospectively in future studies.

Severe hematotoxicity after CD19 CAR-T therapy is associated with suppressive immune dysregulation and limited CAR-T expansion

Prolonged cytopenias after chimeric antigen receptor (CAR) T cell therapy are a significant clinical problem and the underlying pathophysiology remains poorly understood. Here, we investigated how (CAR) T cell expansion dynamics and serum proteomics affect neutrophil recovery phenotypes after CD19-directed CAR T cell therapy. Survival favored patients with "intermittent" neutrophil recovery (e.g., recurrent neutrophil dips) compared to either "quick" or "aplastic" recovery. While intermittent patients displayed increased CAR T cell expansion, aplastic patients exhibited an unfavorable relationship between expansion and tumor burden. Proteomics of patient serum collected at baseline and in the first month after CAR-T therapy revealed higher markers of endothelial dysfunction, inflammatory cytokines, macrophage activation, and T cell suppression in the aplastic phenotype group. Prolonged neutrophil aplasia thus occurs in patients with systemic immune dysregulation at baseline with subsequently impaired CAR-T expansion and myeloid-related inflammatory changes. The association between neutrophil recovery and survival outcomes highlights critical interactions between host hematopoiesis and the immune state stimulated by CAR-T infusion.

Inferior Outcomes of EU Versus US Patients Treated With CD19 CAR-T for Relapsed/Refractory Large B-cell Lymphoma: Association With Differences in Tumor Burden, Systemic Inflammation, Bridging Therapy Utilization, and CAR-T Product Use

Real-world evidence suggests a trend toward inferior survival of patients receiving CD19 chimeric antigen receptor (CAR) T-cell therapy in Europe (EU) and with tisagenlecleucel. The underlying logistic, patient- and disease-related reasons for these discrepancies remain poorly understood. In this multicenter retrospective observational study, we studied the patient-individual journey from CAR-T indication to infusion, baseline features, and survival outcomes in 374 patients treated with tisagenlecleucel (tisa-cel) or axicabtagene-ciloleucel (axi-cel) in EU and the United States (US). Compared with US patients, EU patients had prolonged indication-to-infusion intervals (66 versus 50 d; P < 0.001) and more commonly received intermediary therapies (holding and/or bridging therapy, 94% in EU versus 74% in US; P < 0.001). Baseline lactate dehydrogenase (LDH) (median 321 versus 271 U/L; P = 0.02) and ferritin levels (675 versus 425 ng/mL; P = 0.004) were significantly elevated in the EU cohort. Overall, we observed inferior survival in EU patients (median progression-free survival [PFS] 3.1 versus 9.2 months in US; P < 0.001) and with tisa-cel (3.2 versus 9.2 months with axi-cel; P < 0.001). On multivariate Lasso modeling, nonresponse to bridging, elevated ferritin, and increased C-reactive protein represented independent risks for treatment failure. Weighing these variables into a patient-individual risk balancer (high risk [HR] balancer), we found higher levels in EU versus US and tisa-cel versus axi-cel cohorts. Notably, superior PFS with axi-cel was exclusively evident in patients at low risk for progression (according to the HR balancer), but not in high-risk patients. These data demonstrate that inferior survival outcomes in EU patients are associated with longer time-to-infusion intervals, higher tumor burden/LDH levels, increased systemic inflammatory markers, and CAR-T product use.

Staging of lymphoma under chimeric antigen receptor T-cell therapy: reasons for discordance among imaging response criteria

BACKGROUND

Chimeric antigen receptor T-cell therapy (CART) prolongs survival for patients with refractory or relapsed lymphoma. Discrepancies among different response criteria for lymphoma under CART were recently shown. Our objective was to evaluate reasons for discordance among different response criteria and their relation to overall survival.

METHODS

Consecutive patients with baseline and follow-up imaging at 30 (FU1) and 90 days (FU2) after CART were included. Overall response was determined based on Lugano, Cheson, response evaluation criteria in lymphoma (RECIL) and lymphoma response to immunomodulatory therapy criteria (LYRIC). Overall response rate (ORR) and rates of progressive disease (PD) were determined. For each criterion reasons for PD were analyzed in detail.

RESULTS

41 patients were included. ORR was 68%, 68%, 63%, and 68% at FU2 by Lugano, Cheson, RECIL, and LYRIC, respectively. PD rates differed among criteria with 32% by Lugano, 27% by Cheson, 17% by RECIL, and 17% by LYRIC. Dominant reasons for PD according to Lugano were target lesion (TL) progression (84.6%), new appearing lesions (NL; 53.8%), non-TL progression (27.3%), and progressive metabolic disease (PMD; 15.4%). Deviations among the criteria for defining PD were largely explained by PMD of preexisting lesions that are defined as PD only by Lugano and non-TL progression, which is not defined as PD by RECIL and in some cases classified as indeterminate response by LYRIC.

CONCLUSIONS

Following CART, lymphoma response criteria show differences in imaging endpoints, especially in defining PD. The response criteria must be considered when interpreting imaging endpoints and outcomes from clinical trials.

Influence of adipose tissue distribution, sarcopenia, and nutritional status on clinical outcomes after CD19 CAR T-cell therapy

Although CD19-directed chimeric antigen receptor T-cell therapy (CD19.CAR-T) has proven clinical efficacy for multiple refractory B-cell malignancies, over 50% of patients ultimately relapse. Recent evidence has underlined the critical role of the host in determining treatment responses. In this retrospective observational study of 106 relapsed/refractory large B-cell lymphoma (LBCL) patients receiving standard-of-care CD19.CAR-T, we analyzed the impact of immunometabolic host features and detailed body composition measurements on post-CAR-T clinical outcomes. We extracted muscle and adipose tissue distributions from pre-lymphodepletion CT images and assessed laboratory-based immuno-nutritional scores. Early responders displayed increased total abdominal adipose tissue deposits (TAT: 336 vs. 266 mm3, P=0.008) and favorable immuno-nutritional scores compared to non-responding patients. On univariate Cox regression analysis, visceral fat distribution, sarcopenia, and nutritional indices significantly impacted both progression-free (PFS) and overall survival (OS). Patients with a low skeletal muscle index (e.g. SMI<34.5), a sarcopenia indicator, exhibited poor clinical outcomes (mOS 3.0 vs. 17.6 months, log-rank p=0.0026). Prognostically adverse immuno-nutritional scores were linked to inferior survival (low PNI, HROS: 6.31, 95% CI: 3.35-11.90, P<0.001). In a multivariable analysis adjusting for baseline ECOG, CRP, and LDH, increased TAT independently associated with improved clinical outcomes (adjusted HROS: 0.27, 95% CI: 0.08-0.90, P=0.03). We noted particularly favorable treatment outcomes in patients with both increased abdominal fat and muscle mass (TAThigh/SMIhigh: 1-yr PFS 50%, 1-yr OS 83%). These real-world data provide evidence for a role of body composition and immuno-nutritional status in the context of CD19.CAR-T and suggest that the obesity paradox extends to modern T-cell based immunotherapies.

Prognostic value of pre-infusion tumor growth rate for patients with lymphoma receiving chimeric antigen receptor T-cell therapy

BACKGROUND AIMS

Chimeric antigen receptor T-cell therapy (CART) prolongs survival for patients with refractory or relapsed lymphoma, yet its efficacy is affected by the tumor burden. The relevance of tumor kinetics before infusion is unknown. We aimed to study the prognostic value of the pre-infusion tumor growth rate (TGR^pre-BL) for progression-free (PFS) and overall survival (OS).

METHODS

Consecutive patients with available pre-baseline (pre-BL) and baseline (BL) computed tomography or positron emission tomography/computed tomography scan before CART were included. TGR was determined as change of Lugano criteria-based tumor burden between pre-BL, BL and follow-up examinations (FU) in relation to days between imaging exams. Overall response rate (ORR), depth or response (DoR) and PFS were determined based on Lugano criteria. Multivariate regression analysis studied association of TGR with ORR and DoR. Proportional Cox regression analysis studied association of TGR with PFS and OS.

RESULTS

In total, 62 patients met the inclusion criteria. The median TGR^pre-BL was 7.5 mm²/d (interquartile range -14.6 mm²/d to 48.7 mm²/d); TGR^pre-BL was positive (TGR^{pre-BL POS}) in 58% of patients and negative (TGR^{pre-BL NEG}, indicating tumor shrinkage) in 42% of patients. Patients who were TGR^{pre-BL POS} had a 90-day (FU2) ORR of 62%, a DoR of -86% and a median PFS of 124 days. Patients who were TGR^{pre-BL NEG} had a 90-day ORR of 44%, DoR of -47% and a median PFS of 105 days. ORR and DoR were not associated with slower TGR (P = 0.751, P = 0.198). Patients with an increase of TGR from pre-BL over BL to 30-day FU (FU1) ≥100% (TGR^{pre-BL-to-FU1≥100%}) showed a significant association with shorter median PFS (31 days versus 343 days, P = 0.002) and shorter median OS after CART (93 days versus not reached, P < 0.001), compared with patients with TGR^{pre-BL-to-FU1<100%}.

CONCLUSIONS

In the context of CART, differences in pre-infusion tumor kinetics showed minor differences in ORR, DoR, PFS and OS, whereas the change of the TGR from pre-BL to 30-day FU significantly stratified PFS and OS. In this patient population of refractory or relapsed lymphomas, TGR is readily available based on pre-BL imaging, and its change throughout CART should be explored as a potential novel imaging biomarker of early response.

A non-antibiotic-disrupted gut microbiome is associated with clinical responses to CD19-CAR-T cell cancer immunotherapy

Increasing evidence suggests that the gut microbiome may modulate the efficacy of cancer immunotherapy. In a B cell lymphoma patient cohort from five centers in Germany and the United States (Germany, n = 66; United States, n = 106; total, n = 172), we demonstrate that wide-spectrum antibiotics treatment ('high-risk antibiotics') prior to CD19-targeted chimeric antigen receptor (CAR)-T cell therapy is associated with adverse outcomes, but this effect is likely to be confounded by an increased pretreatment tumor burden and systemic inflammation in patients pretreated with high-risk antibiotics. To resolve this confounding effect and gain insights into antibiotics-masked microbiome signals impacting CAR-T efficacy, we focused on the high-risk antibiotics non-exposed patient population. Indeed, in these patients, significant correlations were noted between pre-CAR-T infusion Bifidobacterium longum and microbiome-encoded peptidoglycan biosynthesis, and CAR-T treatment-associated 6-month survival or lymphoma progression. Furthermore, predictive pre-CAR-T treatment microbiome-based machine learning algorithms trained on the high-risk antibiotics non-exposed German cohort and validated by the respective US cohort robustly segregated long-term responders from non-responders. Bacteroides, Ruminococcus, Eubacterium and Akkermansia were most important in determining CAR-T responsiveness, with Akkermansia also being associated with pre-infusion peripheral T cell levels in these patients. Collectively, we identify conserved microbiome features across clinical and geographical variations, which may enable cross-cohort microbiome-based predictions of outcomes in CAR-T cell immunotherapy.

Identifying Early Infections in the Setting of CRS With Routine and Exploratory Serum Proteomics and the HT10 Score Following CD19 CAR-T for Relapsed/Refractory B-NHL

Early fever after chimeric antigen receptor T-cell (CAR-T) therapy can reflect both an infection or cytokine release syndrome (CRS). Identifying early infections in the setting of CRS and neutropenia represents an unresolved clinical challenge. In this retrospective observational analysis, early fever events (day 0-30) were characterized as infection versus CRS in 62 patients treated with standard-of-care CD19.CAR-T for relapsed/refractory B-cell non-Hodgkin lymphoma. Routine serum inflammatory markers (C-reactive protein [CRP], interleukin-6 [IL-6], procalcitonin [PCT]) were recorded daily. Exploratory plasma proteomics were performed longitudinally in 52 patients using a multiplex proximity extension assay (Olink proteomics). Compared with the CRS^only cohort, we noted increased event-day IL-6 (median 2243 versus 64 pg/mL, P = 0.03) and particularly high PCT levels (median 1.6 versus 0.3 µg/L, P < 0.0001) in the patients that developed severe infections. For PCT, an optimal discriminatory threshold of 1.5 µg/L was established (area under the receiver operating characteristic curve [AUC_ROC] = 0.78). Next, we incorporated day-of-fever PCT levels with the patient-individual CAR-HEMATOTOX score. In a multicenter validation cohort (n = 125), we confirmed the discriminatory capacity of this so-called HT10 score for early infections at first fever (AUC_ROC = 0.87, P < 0.0001, sens. 86%, spec. 86%). Additionally, Olink proteomics revealed pronounced immune dysregulation and endothelial dysfunction in patients with severe infections as evidenced by an increased ANGPT2/1 ratio and an altered CD40/CD40L-axis. In conclusion, the high discriminatory capacity of the HT10 score for infections highlights the advantage of dynamic risk assessment and supports the incorporation of PCT into routine inflammatory panels. Candidate markers from Olink proteomics may further refine risk-stratification. If validated prospectively, the score will enable risk-adapted decisions on antibiotic use.

Prognostic value of the International Metabolic Prognostic Index for lymphoma patients receiving chimeric antigen receptor T-cell therapy

PURPOSE

Chimeric antigen receptor T-cell therapy (CART) prolongs survival for patients with relapsed/refractory B-cell non-Hodgkin's lymphoma. The recently introduced International Metabolic Prognostic Index (IMPI) was shown to improve prognostication in the first-line treatment of large B-cell lymphoma. Here, we investigate the prognostic value of the IMPI for progression-free (PFS) and overall survival (OS) in the setting of CD19 CART.

METHODS

Consecutively treated patients with baseline ¹⁸F-FDG PET/CT imaging and follow-up imaging at 30 days after CART were included. IMPI is composed of age, stage, and metabolic tumor volume (MTV) at baseline and was compared with the International Prognostic Index (IPI). Both indices were grouped into quartiles, as previously described for IPI. In addition, the continuous IMPI was subdivided into tertiaries for better separation of risk groups. Overall response rate (ORR), depth of response (DoR), and PFS were determined based on Lugano criteria. Proportional Cox regression analysis studied association of IMPI and IPI with PFS and OS.

RESULTS

Thirty-nine patients were included. The IPI was 1 in 23%, 2 in 21%, 3 in 26%, 4 in 21%, and 5 in 10% of the patients. IMPI^{low risk}, IMPI^{intermediate risk}, and IMPI^{high risk} patients had 30-day ORR of 69%, 62%, and 62% and 30-day DoR of - 67%, - 66%, and - 54% with a PFS of 187 days, 97 days, and 87 days, respectively. ORR and DoR showed no correlation with lower IMPI (r = 0.065, p = 0.697). Dividing patients into three risk groups showed a significant trend for PFS stratification (p = 0.030), while IPI did not (p = 0.133). Neither IPI nor IMPI yielded a significant association with OS after CART (both p > 0.05).

CONCLUSION

In the context of CART, the IMPI yielded prognostic value regarding PFS estimation. In contrast with IMPI in the first-line DLBCL setting, we did not observe a significant association of IMPI at baseline with OS after CART.

Functional connectivity MRI provides an imaging correlate for chimeric antigen receptor T-cell-associated neurotoxicity

Background

Treatment of hematological malignancies with chimeric antigen receptor modified T cells (CART) is highly efficient, but often limited by an immune effector cell-associated neurotoxicity syndrome (ICANS). As conventional MRI is often unremarkable during ICANS, we aimed to examine whether resting-state functional MRI (rsfMRI) is suitable to depict and quantify brain network alterations underlying ICANS in the individual patient.

Methods

The dysconnectivity index (DCI) based on rsfMRI was longitudinally assessed in systemic lymphoma patients and 1 melanoma patient during ICANS and before or after clinical resolution of ICANS.

Results

Seven lymphoma patients and 1 melanoma patient (19-77 years; 2 female) were included. DCI was significantly increased during ICANS with normalization after recovery (P = .0039). Higher ICANS grades were significantly correlated with increased DCI scores (r = 0.7807; P = .0222). DCI increase was most prominent in the inferior frontal gyrus and the frontal operculum (ie, Broca's area) and in the posterior parts of the superior temporal gyrus and the temporoparietal junction (ie, Wernicke's area) of the language-dominant hemisphere, thus reflecting the major clinical symptoms of nonfluent dysphasia and dyspraxia.

Conclusions

RsfMRI-based DCI might be suitable to directly quantify the severity of ICANS in individual patients undergoing CAR T-transfusion. Besides ICANS, DCI seems a promising diagnostic tool to quantify functional brain network alterations during encephalopathies of different etiologies, in general.

A polyamine-centric, blood-based metabolite panel predictive of poor response to CAR-T cell therapy in large B cell lymphoma

Anti-CD19 chimeric antigen receptor (CAR) T cell therapy for relapsed or refractory (r/r) large B cell lymphoma (LBCL) results in durable response in only a subset of patients. MYC overexpression in LBCL tumors is associated with poor response to treatment. We tested whether an MYC-driven polyamine signature, as a liquid biopsy, is predictive of response to anti-CD19 CAR-T therapy in patients with r/r LBCL. Elevated plasma acetylated polyamines were associated with non-durable response. Concordantly, increased expression of spermidine synthase, a key enzyme that regulates levels of acetylated spermidine, was prognostic for survival in r/r LBCL. A broad metabolite screen identified additional markers that resulted in a 6-marker panel (6MetP) consisting of acetylspermidine, diacetylspermidine, and lysophospholipids, which was validated in an independent set from another institution as predictive of non-durable response to CAR-T therapy. A polyamine centric metabolomics liquid biopsy panel has predictive value for response to CAR-T therapy in r/r LBCL.

Lymphoma tumor burden before chimeric antigen receptor T-Cell treatment: RECIL vs. Lugano vs. metabolic tumor assessment

Purpose

High tumor burden has emerged as a negative predictor of efficacy in chimeric antigen receptor T-cell therapy (CART) in patients with refractory or relapsed large B-cell lymphoma. This study analyzed the deviation among imaging-based tumor burden (TB) metrics and their association with progression-free (PFS) and overall survival (OS).

Materials and methods

In this single-center observational study, we included all consecutively treated patients receiving CD19 CART with available baseline PET-CT imaging. Imaging-based TB was determined based on response evaluation criteria in lymphoma (RECIL), the Lugano criteria, and metabolic tumor volume. Total, nodal and extranodal TB were represented, according to the respective criteria, by sum of longest diameters (TB_RECIL), sum of product of perpendicular diameters (TB_Lugano), and metabolic tumor volume (TB_MTV). Correlation statistics were used for comparison. Proportional Cox regression analysis studied the association of TB metrics with PFS and OS.

Results

34 consecutive patients were included (median age: 67 years, 41% female) with total median baseline TB_RECIL of 12.5 cm, TB_Lugano of 4,030 mm² and TB_MTV of 330 mL. The correlation of TB_RECIL and TB_Lugano with TB_MTV was strong (ρ=0.744, p<0.001 and ρ=0.741, p<0.001), with lowest correlation for extranodal TB_RECIL with TB_MTV (ρ=0.660, p<0.001). Stratification of PFS was strongest by total TB_MTV>50% (HR=2.915, p=0.042), whereas total TB_RECIL>50% and total TB_Lugano>50% were not significant (both p>0.05). None of the total TB metrics were associated with OS (all p>0.05).

Conclusion

Pre-CART TB metrics vary significantly based on the assessment method, impacting their association with survival outcomes. The correlation between TB_RECIL, TB_Lugano and TB_MTV was influenced by disease phenotype and prior bridging therapy. TB method of assessment must be considered when interpreting the impact of TB on outcomes in clinical trials. Considering the heterogeneity, our results argue for standardization and harmonization across centers.

The CAR-HEMATOTOX risk-stratifies patients for severe infections and disease progression after CD19 CAR-T in R/R LBCL

Background

CD19-directed chimeric antigen receptor T-cell therapy (CAR-T) represents a promising treatment modality for an increasing number of B-cell malignancies. However, prolonged cytopenias and infections substantially contribute to the toxicity burden of CAR-T. The recently developed CAR-HEMATOTOX (HT) score—composed of five pre-lymphodepletion variables (eg, absolute neutrophil count, platelet count, hemoglobin, C-reactive protein, ferritin)—enables risk stratification of hematological toxicity.

Methods

In this multicenter retrospective analysis, we characterized early infection events (days 0–90) and clinical outcomes in 248 patients receiving standard-of-care CD19 CAR-T for relapsed/refractory large B-cell lymphoma. This included a derivation cohort (cohort A, 179 patients) and a second independent validation cohort (cohort B, 69 patients). Cumulative incidence curves were calculated for all-grade, grade ≥3, and specific infection subtypes. Clinical outcomes were studied via Kaplan-Meier estimates.

Results

In a multivariate analysis adjusted for other baseline features, the HT score identified patients at high risk for severe infections (adjusted HR 6.4, 95% CI 3.1 to 13.1). HT^high patients more frequently developed severe infections (40% vs 8%, p<0.0001)—particularly severe bacterial infections (27% vs 0.9%, p<0.0001). Additionally, multivariate analysis of post-CAR-T factors revealed that infection risk was increased by prolonged neutropenia (≥14 days) and corticosteroid use (≥9 days), and decreased with fluoroquinolone prophylaxis. Antibacterial prophylaxis significantly reduced the likelihood of severe bacterial infections in HT^high (16% vs 46%, p<0.001), but not HT^low patients (0% vs 2%, p=n.s.). Collectively, HT^high patients experienced worse median progression-free (3.4 vs 12.6 months) and overall survival (9.1 months vs not-reached), and were hospitalized longer (median 20 vs 16 days). Severe infections represented the most common cause of non-relapse mortality after CAR-T and were associated with poor survival outcomes. A trend toward increased non-relapse mortality in HT^high patients was observed (8.0% vs 3.7%, p=0.09).

Conclusions

These data demonstrate the utility of the HT score to risk-stratify patients for infectious complications and poor survival outcomes prior to CD19 CAR-T. High-risk patients likely benefit from anti-infective prophylaxis and should be closely monitored for potential infections and relapse.

Toxicities and Response Rates of Secondary CNS Lymphoma After Adoptive Immunotherapy With CD19-Directed Chimeric Antigen Receptor T Cells

Background and Objectives

Secondary CNS involvement in systemic B-cell lymphoma (SCNSL) is difficult to treat and displays dismal clinical outcomes. Chimeric antigen receptor (CAR) T cells emerged as a powerful treatment for systemic lymphoma. We aimed to evaluate whether CAR T cells also represent a safe and effective therapy for SCNSL.

Methods

We retrospectively searched our institutional database for patients with SCNSL treated with CD19-directed CAR T cells.

Results

We identified 10 cases, including 7 patients with intraparenchymal lesions and 3 patients with leptomeningeal disease. CNS staging at 1 month after CAR T-cell transfusion showed disease response (stable disease, partial response, and complete response) in 7 patients (70%), including 2 cases of long-lasting complete response (20%). One patient developed pseudoprogression, which resolved under steroids. Response of CNS disease was associated with systemic 1-month response. With a median follow-up of 6 months, median overall and systemic progression-free survival was 7 and 3 months, respectively. Neurotoxic symptoms occurred in 6 patients, with 3 patients developing severe neurotoxicity (American Society for Transplantation and Cellular Therapy grade ≥3).

Discussion

CAR T cells induce considerable antitumor effects in SCNSL, and CNS response reflects systemic response. Neurotoxicity appears similar to previous reports on patients with lymphoma without CNS involvement. CAR T cells may therefore represent an effective and safe therapy for SCNSL.

Increased visceral fat distribution and body composition impact cytokine release syndrome onset and severity after CD19 CAR-T in advanced B-cell malignancies

Chimeric antigen receptor T-cell (CAR-T) therapy is associated with a distinct toxicity profile that includes cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). CRS is characterized by the release of pro-inflammatory cytokines such as interleukin 6 (IL-6) and is closely linked to CAR-T expansion and bystander cells like monocytes/macrophages. In other hyperinflammatory states, obesity contributes to inflammatory cascades and acts as a risk factor for disease severity. We aimed to study the influence of anthropometric and body composition (BC) measurements on CAR-T-related immunotoxicity in 64 patients receiving CD19-directed CAR-T for relapsed/refractory B-cell malignancies. Patients with grade ≥2 CRS presented with a significantly higher median body mass index (BMI), waist circumference, waist-to-height ratio (WtHR) and visceral adipose tissue (VAT). These parameters were also found to be associated with an earlier CRS onset. Other adipose deposits and muscle mass did not differ between patients with grade 0-1 CRS versus grade ≥2 CRS. Moreover, BC parameters did not influence ICANS severity or onset. In a multivariate binary logistic regression incorporating known risk factors of immunotoxicity, the factors BMI, waist circumference, WtHR and VAT increased the probability of grade ≥2 CRS. Receiver operating characteristic analyses were utilized to determine optimal discriminatory thresholds for these parameters. Patients above these thresholds displayed markedly increased peak IL-6 levels. Our data imply that increased body composition and VAT in particular represent an additional risk factor for severe and early CRS. These findings carry implications for risk-stratification prior to CD19 CAR-T and may be integrated into established risk models.

T cells armed with C-X-C chemokine receptor type 6 enhance adoptive cell therapy for pancreatic tumours

The efficacy of adoptive cell therapy for solid tumours is hampered by the poor accumulation of the transferred T cells in tumour tissue. Here, we show that forced expression of C-X-C chemokine receptor type 6 (whose ligand is highly expressed by human and murine pancreatic cancer cells and tumour-infiltrating immune cells) in antigen-specific T cells enhanced the recognition and lysis of pancreatic cancer cells and the efficacy of adoptive cell therapy for pancreatic cancer. In mice with subcutaneous pancreatic tumours treated with T cells with either a transgenic T-cell receptor or a murine chimeric antigen receptor targeting the tumour-associated antigen epithelial cell adhesion molecule, and in mice with orthotopic pancreatic tumours or patient-derived xenografts treated with T cells expressing a chimeric antigen receptor targeting mesothelin, the T cells exhibited enhanced intratumoral accumulation, exerted sustained anti-tumoral activity and prolonged animal survival only when co-expressing C-X-C chemokine receptor type 6. Arming tumour-specific T cells with tumour-specific chemokine receptors may represent a promising strategy for the realization of adoptive cell therapy for solid tumours.

[Practical aspects of the application of CAR T cells and management of their toxicities]

CD19 CAR T cells induce - in part long-lasting - remissions in heavily pretreated patients with relapsed/refractory B-cell malignancies. However, they are associated with unique toxicities, and patient management therefore requires specific expertise.In this review, we outline the basics of their mode of action and present the currently available data on their efficacy in various B-cell and plasma cell malignancies. Currently approved therapies (Tisagenlecleucel, Axicabtagene ciloleucel, Brexucabtagene autoleucel) for patients are outlined as well as indications where approvals are expected in the near future. We discuss practical aspects of CAR T cell therapy from the patient's initial presentation, over leukapheresis, to CAR T cell transfusion. Additionally, we highlight the pathophysiology and principles of the management of the most common toxicities (cytokine release syndrome [CRS], immune cell associated neurotoxicity syndrome [ICANS] and cytopenias).

Severe Candida glabrata pancolitis and fatal Aspergillus fumigatus pulmonary infection in the setting of bone marrow aplasia after CD19-directed CAR T-cell therapy - a case report

Background

Prolonged myelosuppression following CD19-directed CAR T-cell transfusion represents an important, yet underreported, adverse event. The resulting neutropenia and multifactorial immunosuppression can facilitate severe infectious complications.

Case presentation

We describe the clinical course of a 59-year-old patient with relapsed/refractory DLBCL who received Axicabtagene-Ciloleucel (Axi-cel). The patient developed ASTCT grade I CRS and grade IV ICANS, necessitating admission to the neurological ICU and prolonged application of high-dose corticosteroids and other immunosuppressive agents. Importantly, neutropenia was profound (ANC < 100/μl), G-CSF-refractory, and prolonged, lasting more than 50 days. The patient developed severe septic shock 3 weeks after CAR transfusion while receiving anti-fungal prophylaxis with micafungin. His clinical status stabilized with broad anti-infective treatment and intensive supportive measures. An autologous stem cell backup was employed on day 46 to support hematopoietic recovery. Although the counts of the patient eventually started to recover, he developed an invasive pulmonary aspergillosis, which ultimately lead to respiratory failure and death. Postmortem examination revealed signs of Candida glabrata pancolitis.

Conclusions

This case highlights the increased risk for fatal infectious complications in patients who present with profound and prolonged cytopenia after CAR T-cell therapy. We describe a rare case of C. glabrata pancolitis associated with multifactorial immunosuppression. Although our patient succumbed to a fatal fungal infection, autologous stem cell boost was able to spur hematopoiesis and may represent an important therapeutic strategy for DLBCL patients with CAR T-cell associated bone marrow aplasia who have underwent prior stem cell harvest.