CAR T-cell toxicities: from bedside to bench, how novel toxicities inform laboratory investigations.

ABSTRACT: Multiple chimeric antigen receptor (CAR) T-cell therapies are US Food and Drug Administration-approved, and several are under development. Although effective for some cancers, toxicities remain a limitation. The most common toxicities, that is, cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, are well described. With increasing utilization, providers worldwide are reporting other emergent and often complicated toxicities. Given the evolving toxicity profiles and urgent need to catalog these emerging and emergent CAR T-cell toxicities and describe management approaches, the American Society of Hematology Subcommittee on Emerging Gene and Cell Therapies organized the first scientific workshop on CAR T-cell toxicities during the annual society meeting. The workshop functioned to (1) aggregate reports of CAR T-cell emergent toxicities, including movement disorders after B-cell maturation antigen CAR T cell, coagulation abnormalities, and prolonged cytopenia; (2) disseminate bedside-to-bench efforts elucidating pathophysiological mechanisms of CAR T-cell toxicities, including the intestinal microbiota and systemic immune dysregulation; and (3) highlight gaps in the availability of clinical tests, such as cytokine measurements, which could be used to expand our knowledge around the monitoring of toxicities. Key themes emerged. First, although clinical manifestations may develop before the pathophysiologic mechanisms are understood, they must be studied to aid in the detection and prevention of such toxicities. Second, systemic immune dysregulation appears to be central to these emergent toxicities, and research is needed to elucidate the links between tumors, CAR T cells, and microbiota. Finally, there was a consensus around the urgency to create a repository to capture emergent CAR T-cell toxicities and the real-world management.

Thrombotic Events Are Unusual Toxicities of Chimeric Antigen Receptor T-Cell Therapies.

Chimeric antigen receptor (CAR) T-cell therapy has greatly transformed the treatment and prognosis of B-cell hematological malignancies. As CAR T-cell therapy continues to be more readily adopted and indications increase, the field's recognition of emerging toxicities will continue to grow. Among the adverse events associated with CAR T-cell therapy, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity (ICANS) are the most common toxicities, while thrombotic events represent an under-reported, life-endangering complication. To determine thrombosis incidence post CAR T-cell therapy, we performed a multi-center, retrospective study on CAR T-cell therapy adult patients (N = 140) from Indiana University Simon Cancer Center and the University of North Carolina Medical Center treated from 2017 to 2022 for relapsed and refractory B-cell acute lymphoblastic leukemia (B-ALL, N = 3), diffuse large B-cell lymphoma (DLBCL, N = 92), follicular lymphoma (FL, N = 9), mantle cell lymphoma (MCL, N = 2), and multiple myeloma (MM, N = 34). We report 10 (7.14%) thrombotic events related to CAR T-cell therapy (DLBCL: N = 8, FL: N = 1, MM: N = 1) including 9 primary venous events and 1 arterial event that occurred with median time of 23.5 days post CAR T-cell infusion. In search of parameters associated with such events, we performed multivariate analyses of coagulation parameters (i.e., PT, PTT, and D-Dimer), scoring for adverse events (Padua Score and ISTH DIC Score) and grading for CAR T-cell toxicity severity (CRS grade and ICANS grade) and found that D-Dimer peak elevation and ICANS grade were significantly associated with post-CAR T-cell infusion thrombosis. While the pathophysiology of CAR T-cell associated coagulopathy remains unknown, our study serves to develop awareness of these emerging and unusual complications.

Oral Iron Replacement Normalizes Fibroblast Growth Factor 23 in Iron-Deficient Patients With Autosomal Dominant Hypophosphatemic Rickets.

Autosomal dominant hypophosphatemic rickets (ADHR) is caused by mutations impairing cleavage of fibroblast growth factor 23 (FGF23). FGF23 gene expression increases during iron deficiency. In humans and mice with the ADHR mutation, iron deficiency results in increased intact FGF23 concentrations and hypophosphatemia. We conducted a prospective open label pilot clinical trial of oral iron replacement over 12 months in ADHR patients to test the hypothesis that oral iron administration would normalize FGF23 concentrations. Eligibility criteria included: FGF23 mutation; and either serum iron <50 µg/dL; or serum iron 50 to 100 µg/dL combined with hypophosphatemia and intact FGF23 >30 pg/mL at screening. Key exclusion criteria were kidney disease and pregnancy. Oral iron supplementation started at 65 mg daily and was titrated based on fasting serum iron concentration. The primary outcome was decrease in fasting intact FGF23 by ≥20% from baseline. Six adults (three male, three female) having the FGF23-R176Q mutation were enrolled; five completed the 12-month protocol. At baseline three of five subjects had severely symptomatic hypophosphatemia (phosphorus <2.5 mg/dL) and received calcitriol with or without phosphate concurrent with oral iron during the trial. The primary outcome was met by 4 of 5 (80%) subjects all by month 4, and 5 of 5 had normal intact FGF23 at month 12. Median (minimum, maximum) intact FGF23 concentration decreased from 172 (20, 192) pg/mL at baseline to 47 (17, 78) pg/mL at month 4 and 42 (19, 63) pg/mL at month 12. Median ferritin increased from 18.6 (7.7, 82.5) ng/mL at baseline to 78.0 (49.6, 261.0) ng/mL at month 12. During iron treatment, all three subjects with baseline hypophosphatemia normalized serum phosphorus, had markedly improved symptoms, and were able to discontinue calcitriol and phosphate. Oral iron repletion normalized FGF23 and phosphorus in symptomatic, iron-deficient ADHR subjects. Thus, the standard approach to ADHR should include recognition, treatment, and prevention of iron deficiency. © 2019 American Society for Bone and Mineral Research.

Experiences of Female and Male Medical Students With Death, Dying, and Palliative Care: One Size Does Not Fit All.

BACKGROUND: Medical students learn about death, dying, and palliative care (DDPC) through formal curricular offerings and informal clinical experiences; however, the lessons learned in the clinic may be at odds with the formal curriculum. Reflective writing is a means for students to "bracket" their DDPC experiences and reconcile conflicts between the formal and informal curriculum. OBJECTIVES: The aim of this study is to compare the level of reflection demonstrated in medical students' narratives on DDPC with other experiences and to examine the domains of professionalism that students perceive to be prevalent in their DDPC experiences. METHODS: Third-year medical students submitted professionalism narratives during their internal medicine clerkship. We identified a subset of narratives related to DDPC (n = 388) and randomly selected control narratives (n = 153). We assessed the level of reflection demonstrated in the narratives using a validated rubric and analyzed the professionalism domains that students identified as relevant to their experience. RESULTS: There was no difference in reflective level between DDPC and control narratives. Within the DDPC group, female students demonstrated higher reflection (2.24 ± 0.71) than male students (2.01 ± 0.77; P < .001). Caring, compassion and communication, and honor and integrity were prominent among DDPC narratives. More females identified caring, compassion, and communication as relevant to their DDPC experiences, whereas more males identified altruism. CONCLUSION: Males and females have different perceptions of DDPC experiences, and female students appear to be more deeply impacted. These findings can help clinical faculty engage students more effectively with this challenging topic.

Physicians in Postgraduate Training Characteristics and Support of Palliative Sedation for Existential Distress.

INTRODUCTION: Palliative sedation for refractory existential distress (PS-ED) is ethically troubling but potentially critical to quality end-of-life (EOL) care. Physicians' in postgraduate training support toward PS-ED is unknown nor is it known how empathy, hope, optimism, or intrinsic religious motivation (IRM) affect their support. These knowledge gaps hinder efforts to support physicians who struggle with patients' EOL care preferences. METHODS: One hundred thirty-four postgraduate physicians rated their support of PS for refractory physical pain (PS-PP) or PS-ED, ranked the importance of patient preferences in ethically challenging situations, and completed measures of empathy, hope, optimism, and IRM. Predictors of PS-ED and PS-PP support were examined using binary and multinomial logistic regression. RESULTS: Only 22.7% of residents were very supportive of PS-ED, and 82.0% were very supportive of PS-PP. Support for PS-PP or PS-ED did not correlate with levels of empathy, hope, optimism, or IRM; however, for residents with lower IRM, greater optimism was associated with greater PS-ED support. In contrast, among residents with higher IRM, optimism was not associated with PS-ED support. CONCLUSIONS: Comparing current results to published surveys, a similar proportion of residents and practicing physicians support PS-ED and PS-PP. In contrast to practicing physicians, however, IRM does not directly influence residents' supportiveness. The interaction between optimism and IRM suggests residents' beliefs and characteristics are salient to their EOL decisions. End-of-life curricula should provide physicians opportunities to reflect on the personal and ethical factors that influence their support for PS-ED.

Incidence of venous thromboembolism in the setting of hematopoietic cell transplantation.

The underlying risk of venous thromboembolism (VTE) is unclear in patients undergoing hematopoietic cell transplantation (HCT). As such, these patients should still be considered at risk for development of VTE due to factors such as their underlying malignancy and the marked inflammatory state that develops from treatment. The purpose of this study was to characterize the incidence of VTE in patients undergoing HCT. Retrospective chart review of patients from the Indiana University Stem Cell Transplant Unit treated between January 1, 2008, and May 24, 2011. Patients were older than 18 years and had undergone HCT. The primary objective was to analyze the incidence of VTE in patients undergoing autologous HCT versus allogeneic HCT. Secondary objectives included documentation of VTE treatment strategies and time to occurrence of VTE. Of the 567 patients who underwent autologous HCT, 14 developed VTE (2.5%), whereas 5 of the 180 patients who underwent allogeneic HCT developed VTE (2.8%; P = 1.000). The median time to development of VTE from admission for HCT was 12 days in the autologous HCT arm versus 19 days in the allogeneic HCT arm (P = 0.610). The most commonly used VTE treatment strategy was enoxaparin (12 out of 19 VTEs). This study illustrates that VTE does occur rarely in patients who have undergone HCT. The optimal treatment regimen in this population requires further evaluation. Until a reliable protocol for treatment and evidence for risk factors are established, providers should be vigilant for occurrence of VTE in these patients.

Chronic myeloid leukemia within a year of kidney transplant with elevated alkaline phosphatase correlated with imatinib therapy.

The incidence of certain malignancies is significantly higher after organ transplant. However, there are rare reports of chronic myeloid leukemia in the posttransplant setting. The average reported interval between a transplant and the diagnosis of chronic myeloid leukemia is 44 months (range, 10- 96 mo). We report 2 patients with chronic myeloid leukemia within 1 year of a kidney transplant, which is significantly shorter than those previously reported. Both patients were receiving mycophenolate mofetil and tacrolimus for immunosuppression. They were treated with imatinib for chronic myeloid leukemia, and both patients demonstrated an isolated elevation of serum alkaline phosphatase that was directly correlated with imatinib. Despite a potential interaction between the 2 drugs, blood levels of tacrolimus and imatinib were not elevated during the course of treatment. Isolated elevation of alkaline phosphatase in this particular setting has not been reported previously.