Serial Evaluation of Preimmunization Antibody Titers in Lymphoma Patients Receiving Chimeric Antigen Receptor T Cell Therapy.

Antibody titers and the potential need for immunization have not been formally studied in recipients of chimeric antigen receptor T cell therapy (CAR-T). Prior studies have shown that CD19-targeted CAR-T can induce persistent B cell aplasia but preserve plasma cells for humoral response. Aiming to assess the immune repertoire and antibody titer status of CAR-T recipients, we conducted a retrospective study of immune cell recovery and antibody titers to vaccines in anti-CD19 CAR-T recipients at Mayo Clinic, Rochester. In our cohort of 95 CAR-T recipients, almost one-half had low CD4 T and B cell counts prior to CAR-T that remained persistently low post-CAR-T. Prior to CAR-T, the seronegative rate was lowest for tetanus and highest for pneumococcus irrespective of prior transplantation status (within 2 years of CAR-T). At 3 months post-CAR-T, overall seronegativity rates were similar to pre-CAR-T rates for the prior transplantation and no prior transplantation groups. For patients who received IVIG, loss of seropositivity was seen for hepatitis A (1 of 7; 14%). No seroconversion was noted for pneumococcus. For patients who did not receive IVIG, loss of seropositivity was seen for pneumococcus (2 of 5; 40%) and hepatitis A (1 of 4; 25%). CAR-T recipients commonly experience T cell and B cell lymphopenia and might not have adequate antibody titers against vaccine-preventable diseases despite IVIG supplementation. Loss of antibody titers post-CAR-T is possible, highlighting the need for revaccination. Additional studies with long-term follow-up are needed to inform the optimal timing of immunization post-CAR-T.

Applying the EHA/EBMT grading for ICAHT after CAR-T: comparative incidence and association with infections and mortality.

ABSTRACT: Cytopenias represent the most common side effect of CAR T-cell therapy (CAR-T) and can predispose for severe infectious complications. Current grading systems, such as the Common Terminology Criteria for Adverse Events (CTCAE), neither reflect the unique quality of post-CAR-T neutrophil recovery, nor do they reflect the inherent risk of infections due to protracted neutropenia. For this reason, a novel EHA/EBMT consensus grading was recently developed for Immune Effector Cell-Associated HematoToxicity (ICAHT). In this multicenter, observational study, we applied the grading system to a large real-world cohort of 549 patients treated with BCMA- or CD19-directed CAR-T for refractory B-cell malignancies (112 multiple myeloma [MM], 334 large B-cell lymphoma [LBCL], 103 mantle cell lymphoma [MCL]) and examined the clinical sequelae of severe (≥3°) ICAHT. The ICAHT grading was strongly associated with the cumulative duration of severe neutropenia (r = 0.92, P < .0001), the presence of multilineage cytopenias, and the use of platelet and red blood cell transfusions. We noted an increased rate of severe ICAHT in patients with MCL vs those with LBCL and MM (28% vs 23% vs 15%). Severe ICAHT was associated with a higher rate of severe infections (49% vs 13%, P < .0001), increased nonrelapse mortality (14% vs 4%, P < .0001), and inferior survival outcomes (1-year progression-free survival: 35% vs 51%, 1-year overall survival: 52% vs 73%, both P < .0001). Importantly, the ICAHT grading demonstrated superior capacity to predict severe infections compared with the CTCAE grading (c-index 0.73 vs 0.55, P < .0001 vs nonsignificant). Taken together, these data highlight the clinical relevance of the novel grading system and support the reporting of ICAHT severity in clinical trials evaluating CAR-T therapies.

Time from immune checkpoint inhibitor to sotorasib use correlates with risk of hepatotoxicity in non-small cell lung cancer: A brief report.

INTRODUCTION: We evaluated the risk factors and outcomes for patients who experienced hepatotoxicity after use of sotorasib in KRAS G12C mutated NSCLC. METHODS: Retrospective review of medical records of patients with KRAS G12C mutated NSCLC who received sotorasib between May 28th, 2021, and December 31st, 2021 across all Mayo Clinic sites, with follow up until December 31st, 2022. RESULTS: Thirty-one patients received sotorasib as standard of care treatment. Grade 3 or higher hepatoxicity was seen in 32% (10/31) patients presenting at a median of 51 days (range, 27-123) of sotorasib initiation. Baseline demographics were comparable between patients with and without ≥grade 3 hepatotoxicity, except for presence of CNS metastases and time from prior immune checkpoint inhibitor (ICI) treatment. Improvement in liver tests was observed in all patients after stopping sotorasib, and it was restarted at a lower dose in 8 patients. Despite dose reduction, hepatotoxicity requiring sotorasib discontinuation occurred in 2 patients. Twenty-eight of 31 patients had received prior ICI. Median time from prior ICI therapy was 69 days (range, 4-542). Rates of ≥grade 3 hepatoxicity were 75% (3/4), 64% (7/11) and 0% (0/13) for patients who received ICI within 30 days, 31-90 days and >90 days. None of the 3 patients without prior ICI exposure developed hepatoxicity. The median PFS and OS were 3.9 months and 9.9 months respectively. CONCLUSION: One-third of patients developed grade 3 or higher sotorasib induced hepatotoxicity. Risk of hepatotoxicity was higher in patients who received sotorasib within 90 days of ICI treatment.

Metabolic PET/CT analysis of aggressive Non-Hodgkin lymphoma prior to Axicabtagene Ciloleucel CAR-T infusion: predictors of progressive disease, survival, and toxicity.

PET/CT is used to evaluate relapsed/refractory non-Hodgkin lymphoma (NHL) prior to chimeric antigen receptor T-cell (CAR-T) infusion at two time points: pre-leukapheresis (pre-leuk) and pre-lymphodepletion chemotherapy (pre-LD). We hypothesized that changes in PET/CT between these time points predict outcomes after CAR-T. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and other metrics were calculated from pre-leuk and pre-LD PET/CT scans in patients with NHL who received axicabtagene ciloleucel, and assessed for association with outcomes. Sixty-nine patients were analyzed. While single time point PET/CT characteristics were not associated with risk of PD or death, increases from pre-leuk to pre-LD in parenchymal MTV, nodal MTV, TLG of the largest lesion, and total number of lesions were associated with increased risk of death (p < 0.05 for all). LASSO analysis identified increasing extranodal MTV and increasing TLG of the largest lesion as strong predictors of death (AUC 0.74). Greater pre-LD total MTV was associated with higher risk of grade 3+ immune effector cell-associated neurotoxicity syndrome (ICANS) (p = 0.042). Increasing metabolic disease burden during CAR-T manufacturing is associated with increased risk of progression and death. A two variable risk score stratifies prognosis prior to CAR-T infusion and may inform risk-adapted strategies.

The CAR-HEMATOTOX score as a prognostic model of toxicity and response in patients receiving BCMA-directed CAR-T for relapsed/refractory multiple myeloma.

BACKGROUND: BCMA-directed CAR T-cell therapy (CAR-T) has altered the treatment landscape of relapsed/refractory (r/r) multiple myeloma, but is hampered by unique side effects that can lengthen hospital stays and increase morbidity. Hematological toxicity (e.g. profound and prolonged cytopenias) represents the most common grade ≥ 3 toxicity and can predispose for severe infectious complications. Here, we examined the utility of the CAR-HEMATOTOX (HT) score to predict toxicity and survival outcomes in patients receiving standard-of-care idecabtagene vicleucel and ciltacabtagene autoleucel. METHODS: Data were retrospectively collected from 113 r/r multiple myeloma patients treated between April 2021 and July 2022 across six international CAR-T centers. The HT score-composed of factors related to hematopoietic reserve and baseline inflammatory state-was determined prior to lymphodepleting chemotherapy. RESULTS: At lymphodepletion, 63 patients were HTlow (score 0-1) and 50 patients were HThigh (score ≥ 2). Compared to their HTlow counterparts, HThigh patients displayed prolonged severe neutropenia (median 9 vs. 3 days, p < 0.001), an increased severe infection rate (40% vs. 5%, p < 0.001), and more severe ICANS (grade ≥ 3: 16% vs. 0%, p < 0.001). One-year non-relapse mortality was higher in the HThigh group (13% vs. 2%, p = 0.019) and was predominantly attributable to fatal infections. Response rates according to IMWG criteria were higher in HTlow patients (≥ VGPR: 70% vs. 44%, p = 0.01). Conversely, HThigh patients exhibited inferior progression-free (median 5 vs. 15 months, p < 0.001) and overall survival (median 10.5 months vs. not reached, p < 0.001). CONCLUSIONS: These data highlight the prognostic utility of the CAR-HEMATOTOX score for both toxicity and treatment response in multiple myeloma patients receiving BCMA-directed CAR-T. The score may guide toxicity management (e.g. anti-infective prophylaxis, early G-CSF, stem cell boost) and help to identify suitable CAR-T candidates.

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

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

Efficacy of checkpoint inhibition after CAR-T failure in aggressive B-cell lymphomas: outcomes from 15 US institutions.

Checkpoint inhibitor (CPI) therapy with anti-PD-1 antibodies has been associated with mixed outcomes in small cohorts of patients with relapsed aggressive B-cell lymphomas after CAR-T failure. To define CPI therapy efficacy more definitively in this population, we retrospectively evaluated clinical outcomes in a large cohort of 96 patients with aggressive B-cell lymphomas receiving CPI therapy after CAR-T failure across 15 US academic centers. Most patients (53%) had diffuse large B-cell lymphoma, were treated with axicabtagene ciloleucel (53%), relapsed early (≤180 days) after CAR-T (83%), and received pembrolizumab (49%) or nivolumab (43%). CPI therapy was associated with an overall response rate of 19% and a complete response rate of 10%. Median duration of response was 221 days. Median progression-free survival (PFS) and overall survival (OS) were 54 and 159 days, respectively. Outcomes to CPI therapy were significantly improved in patients with primary mediastinal B-cell lymphoma. PFS (128 vs 51 days) and OS (387 vs 131 days) were significantly longer in patients with late (>180 days) vs early (≤180 days) relapse after CAR-T. Grade ≥3 adverse events occurred in 19% of patients treated with CPI. Most patients (83%) died, commonly because of progressive disease. Only 5% had durable responses to CPI therapy. In the largest cohort of patients with aggressive B-cell lymphoma treated with CPI therapy after CAR-T relapse, our results reveal poor outcomes, particularly among those relapsing early after CAR-T. In conclusion, CPI therapy is not an effective salvage strategy for most patients after CAR-T, where alternative approaches are needed to improve post-CAR-T outcomes.

Prognostic value of early bone marrow MRD status in CAR-T therapy for myeloma.

Bone marrow (BM) assessment of minimal residual disease (MRD) is prognostic for survival in multiple myeloma (MM). BM is still hypocellular at month 1 post CAR-T, thus the value of MRD negative (MRDneg) status at this timepoint is unclear. We examined the impact of month 1 BM MRD status in MM patients who received CART at Mayo Clinic between 8/2016 and 6/2021. Among 60 patients, 78% were BM-MRDneg at month 1; and 85% (40/47) of these patients also had decreased to less than normal level of both involved and uninvolved free light chain (FLC < NL). Patients who achieved CR/sCR had higher rates of month 1 BM-MRDneg and FLC < NL. The rate of sustained BM-MRDneg was 40% (19/47). Rate of conversion from MRDpos to MRDneg was 5%(1/20). At month 1, 38%(18/47) of the BM-MRDneg were hypocellular. Recovery to normal cellularity was observed in 50%(7/14) with a median time to normalization at 12 months (range: 3-Not reached). Compared to Month 1 BM-MRDpos patients, patients who were BM-MRDneg had longer PFS irrespective of BM cellularity [PFS: 2.9 months (95% CI, 1.2-NR) vs. 17.5 months (95% CI, 10.4-NR), p < 0.0001]. Month 1 BM-MRDneg and FLC below normal were associated with prolonged survival. Our data support the continued evaluation of BM early post-CART infusion as a prognostic tool.

Response to COVID-19 Vaccination Post-CAR T Therapy in Patients With Non-Hodgkin Lymphoma and Multiple Myeloma.

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

Procalcitonin as a biomarker for predicting bacterial infection in chimeric antigen receptor T-cell therapy recipients.

BACKGROUND: It is unknown whether serum procalcitonin (PCT) concentration monitoring can differentiate between bacterial infection or cytokine release syndrome (CRS) when chimeric antigen receptor T-cell (CAR-T) recipients present with a constellation of signs and symptoms that may represent both complications. OBJECTIVE: The objective of the study was to assess the utility of serum PCT concentrations as a biomarker of bacterial infection in CAR-T recipients. STUDY DESIGN: This single-center, retrospective, medical record review evaluated patients prescribed CAR-T therapy until death or 30 days after infusion. Logistic regression modeling determined the association between elevated serum PCT concentrations within 48 h of fever onset and microbiologically confirmed infection. Secondary outcomes included clinically suspected infection, CAR-T toxicity rates, and broad-spectrum antibiotic usage. Predictive performance of PCT was assessed by area under the receiver operating characteristic curve (AUC). RESULTS: The 98 included patients were a median age of 63 (IQR: 55-69) years old, 47 (48%) were male, and 87 (89%) were Caucasian. Baseline demographics and clinical characteristics were similar between patients with and without a bacterial infection. Serum PCT >0.4 ng/mL within 48 h of fever was significantly associated with a microbiologically confirmed bacterial infection (OR: 2.75 [95% CI: 1.02-7.39], p = 0.045). Median PCT values in patients with and without confirmed infections were 0.40 ng/mL (IQR: 0.26, 0.74) and 0.26 ng/mL (IQR: 0.13, 0.47), respectively. The AUC for PCT to predict bacterial infection was 0.62 (95% CI 0.48-0.76). All patients experienced CRS of some grade, with no difference in CRS severity based on elevated PCT. Broad-spectrum antibiotics were used for a median of 45% and 23% of days in those with and without confirmed infection, respectively (p = 0.075). CONCLUSION: Elevated serum PCT concentrations above 0.4 ng/mL at time of first fever after CAR-T infusion was significantly associated with confirmed bacterial infection. Furthermore, rigorous, prospective studies should validate our findings and evaluate serial PCT measurements to optimize antimicrobial use after CAR-T therapy.

Ethical Challenges with Multiple Myeloma BCMA Chimeric Antigen Receptor T Cell Slot Allocation: A Multi-Institution Experience.

Chimeric antigen receptor T cell (CAR-T) therapies are Food and Drug Administration (FDA)-approved for patients with triple refractory multiple myeloma (MM). Real-world access to CAR-T therapy remains challenging owing to supply chain limitations impacting manufacturing. The goal of this study was to evaluate the extent of this issue and how major centers are handling the challenges of CAR-T manufacturing slot allocation. MM CAR-T physician leaders at each CAR-T treatment center across the United States were surveyed. We received responses from 17 of 20 centers. A median of 1 slot is allocated per month per center, and the median number of patients per center on the waitlist since the FDA's approval of idecabtagene vicleucel is 20 (range, 5 to 100). As a result, patients remain on the waitlist for a median of 6 months (range, 2 to 8 months) prior to leukapheresis. For patient selection, all centers reported using a committee of experienced CAR-T physicians to ensure consistency. To ensure transparency, 15 centers make selection criteria, selection timelines, and priority scores readily available for CAR-T providers. Centers also reported using ethical values for selection: (1) equal treatment: time spent on waiting list (n = 12); (2) priority to the worst-off: limited therapeutic options (n = 14), MM burden (n = 11), high Hematopoietic Cell Transplantation Comorbidity Index (n = 5); (3) maximize benefit: most likely to complete apheresis (n = 13) or infusion (n = 13) or to achieve response (n = 8); and (4) social value: younger patients (n = 3). Maximizing benefit was considered the most important criterion by 10 centers. This study is the first attempt to evaluate existing issues with CAR-T access for patients with MM and the variability and challenges in patient selection. Integrating ethical resource allocation strategies, similar to those described here, into formal institutional policies would help streamline access to CAR-T therapy and protect the needs of both current and future patients and physicians.

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

PURPOSE: The optimal approach to incorporate radiation therapy (RT) in conjunction with chimeric antigen receptor (CAR) T-cell therapy (CART) for relapsed/refractory (r/r) B-cell non-Hodgkin lymphoma (bNHL) remains unclear. This study documented the RT local control rate among patients who received bridging radiation therapy (BRT) before CART and compares it with those who received salvage radiation therapy (SRT) after CART. This article further reports on a promising way to use SRT for post-CART disease and identifies predictors for RT in-field recurrence. METHODS AND MATERIALS: We retrospectively reviewed 83 patients with r/r bNHL who received CART and RT, either as BRT pre-CART infusion (n = 35) or as SRT post-CART infusion (n = 48), between 2018 and 2021. RT was defined as comprehensive (compRT; ie, treated all sites of active disease) or focal (focRT). Limited disease was defined as disease amenable to compRT, involving <5 active disease sites. RESULTS: At time of RT, patients who received BRT before CART had bulkier disease sites (median diameter, 8.7 vs 5.5 cm; P = .01) and were treated to significantly lower doses (median equivalent 2-Gy dose, 23.3 vs 34.5 Gy; P = .002), compared with SRT post-CART. Among 124 total irradiated sites identified, 8 of 59 (13%) bridged sites and 21 of 65 (32%) salvaged sites experienced in-field recurrence, translating to 1-year local control rates (LC) of 84% and 62%, respectively (P = .009). Patients with limited post-CART disease (n = 37) who received compSRT (n = 26) had better overall survival (51% vs 12%; P = .028), freedom from subsequent progression (31% vs 0%; P < .001), and freedom from subsequent event (19% vs 0%; P = .011) compared with patients with limited disease who received focSRT (n = 11). CONCLUSIONS: BRT followed by CART appears to be associated with improved LC compared with SRT in r/r bNHL. Nonetheless, SRT offers a promising salvage intervention for limited (<5 sites) relapsed post-CART disease if given comprehensively.

Uncertainty-informed deep learning models enable high-confidence predictions for digital histopathology.

A model's ability to express its own predictive uncertainty is an essential attribute for maintaining clinical user confidence as computational biomarkers are deployed into real-world medical settings. In the domain of cancer digital histopathology, we describe a clinically-oriented approach to uncertainty quantification for whole-slide images, estimating uncertainty using dropout and calculating thresholds on training data to establish cutoffs for low- and high-confidence predictions. We train models to identify lung adenocarcinoma vs. squamous cell carcinoma and show that high-confidence predictions outperform predictions without uncertainty, in both cross-validation and testing on two large external datasets spanning multiple institutions. Our testing strategy closely approximates real-world application, with predictions generated on unsupervised, unannotated slides using predetermined thresholds. Furthermore, we show that uncertainty thresholding remains reliable in the setting of domain shift, with accurate high-confidence predictions of adenocarcinoma vs. squamous cell carcinoma for out-of-distribution, non-lung cancer cohorts.

Incidence and Risk Factors for Acute Kidney Injury After Chimeric Antigen Receptor T-Cell Therapy.

OBJECTIVE: To evaluate the association of baseline and postinfusion patient characteristics with acute kidney injury (AKI) in the month after chimeric antigen receptor T-cell (CAR-T) therapy. METHODS: We retrospectively reviewed records of 83 patients with non-Hodgkin lymphoma undergoing CAR-T therapy (axicabtagene ciloleucel) between June 2016 and November 2020. Patients were followed up to 1 month after treatment. Post-CAR-T AKI was defined as a more than 1.5-fold increase in serum creatinine concentration from baseline (on the day of CAR-T infusion) at any time up to 1 month after CAR-T therapy. RESULTS: Of 83 patients, 14 (17%) developed AKI during follow-up. At 1 month after CAR-T infusion, 10 of 14 (71%) AKI events had resolved. Lower baseline estimated glomerular filtration rate, use of intravenous contrast material, tumor lysis prophylaxis, higher peak uric acid and creatine kinase levels during follow-up, and change in lactate dehydrogenase from baseline to peak level within 1 month after initiation of CAR-T therapy were significantly associated with AKI incidence during follow-up. Incidence of AKI was also higher in patients who received higher doses of corticosteroids and tocilizumab. CONCLUSION: Acute kidney injury occurred in approximately 1 in 6 patients who received axicabtagene ciloleucel for non-Hodgkin lymphoma. Patients with high tumor burden receiving higher total doses of corticosteroids or tocilizumab should be closely monitored for development of AKI. Lower baseline kidney function at CAR-T initiation, exposure to contrast material, and progressive increase in levels of tumor lysis markers (uric acid, lactate dehydrogenase, creatine kinase) after CAR-T infusion may predict risk of AKI during the 1 month after infusion.

Impact of Rituximab and Corticosteroids on Late Cytopenias Post-Chimeric Antigen Receptor T Cell Therapy.

Chimeric antigen receptor (CAR) T cell therapy represents a significant advancement in the treatment of patients with relapsed/refractory B cell lymphoid malignancies. Cytokine release syndrome and immune effector cell-associated neurotoxicity represent the most acute serious adverse events post CAR T cell therapy but the occurrence and persistence of cytopenias post CAR T cell therapy represent a significant adverse event and a management challenge. While most patients typically recover blood counts by 30 days, a significant subset of patients have persistent or late cytopenias beyond 30 days. Patients receiving CAR T cell are heavily pre-treated and the impact of prior therapies on late cytopenias is not well understood. In this study, we found an association between increased number of rituximab infusions and/or cumulative rituximab dose received prior to CAR T cell infusion and persistent anemia and thrombocytopenia at 90 and 180 days afterwards. An overall increased number of prior lines of therapy was also associated with persistent lymphopenia and anemia at 90 days while receiving a prior autologous hematopoietic cell transplant was associated with a greater risk of neutropenia and lymphopenia.