ABSTRACT
Background: Cyclophosphamide (Cy) is used in hematopoietic stem cell transplant (HSCT) preparative regimens and lymphodepletion for chimeric antigen receptor T-cell (CAR-T) therapy. We describe a case of cyclophosphamide hypersensitivity in a pediatric patient during CAR-T therapy. Case description: A 13 year old boy was diagnosed with very high risk ALL in 2015 and had 2 isolated CNS relapses treated with intensified chemotherapy (chemo) and cranial radiation (1st relapse) and Blinatumomab with intrathecal (IT) chemo followed by sibling donor HSCT (2nd relapse). At age 19, and 18 months after HSCT, he had a 3rd CNS relapse treated with IT chemo and referral for CAR-T therapy. At our center, leukapheresis and CAR-T production (Novartis) were performed. Later, during lymphodepletion with fludarabine (Flu) and Cy, physiologic replacement hydrocortisone (HC) was briefly held to prevent interference with CAR-T function. After 3 days of Flu/Cy, he developed fever and hypotension requiring inotropic support. Hypotension and fever resolved with stress dose HC and antibiotics and was attributed to culture-negative sepsis and adrenal crisis. CAR-T infusion was subsequently delayed by skin GVHD requiring glucocorticoids and COVID-19 infection treated with convalescent plasma and nirmatrelvir/ritonavir. Physiologic HC replacement was continued when he was re-admitted for CAR-T therapy, but he again developed fever, diffuse erythema and shock in hours following the first dose of Cy necessitating stress dose HC, antibiotics, inotropes, and mechanical ventilation. Negative blood cultures and ongoing physiologic HC replacement suggested an alternative explanation for shock. Case reports of anaphylaxis to Cy metabolites implicated Cy as the causative agent so it was discontinued. After recovery, CAR-T cells were infused without complications. In the following weeks, he had no evidence of recurrent leukemia but was persistently pancytopenic. A sibling donor stem cell boost was proposed but the patient accepted only palliative care. He had several opportunistic infections before succumbing to E. coli sepsis. Discussion(s): The first episode of shock was initially attributed to adrenal crisis and sepsis, although no organism was identified. The second episode appeared anaphylactic in timing and clinical presentation with adequate HC replacement and negative cultures, suggesting Type I hypersensitivity. The patient previously received Cy uneventfully before HSCT, suggesting that the donor-derived immune system was the source of new Cy hypersensitivity. Onset of anaphylaxis within hours rather than minutes after Cy administration supports hypersensitivity to Cy metabolites rather than to the drug itself. This case highlights the importance of consideration of sensitivity to Cy metabolites as well as acquired donor-specific allergy even when alternative explanations are likely.Copyright © 2023 American Society for Transplantation and Cellular Therapy
ABSTRACT
Background: Cohort A of the multicohort phase 2 CARTITUDE-2 (NCT04133636) study is assessing ciltacabtagene autoleucel (cilta-cel), a B-cell maturation antigen (BCMA)-directed chimeric antigen receptor T-cell (CAR-T) therapy, in patients with multiple myeloma (MM) who received 1-3 prior lines of therapy (LOT) and were refractory to lenalidomide (len). This population is difficult to treat and has poor prognosis. Aims: To present updated results from CARTITUDE-2 Cohort A. Methods: All patients provided informed consent. Eligible patients had progressive MM after 1-3 prior LOT that included a proteasome inhibitor (PI) and an immunomodulatory drug (IMiD). Patients were len-refractory and had no prior exposure to BCMA-targeting agents. Patients received a single cilta-cel infusion (target dose: 0.75×106 CAR+ viable T cells/kg) after lymphodepletion. Cilta-cel safety and efficacy were assessed. The primary endpoint was minimal residual disease (MRD) negativity at 10-5 by next generation sequencing. Patient management strategies were used to reduce the risk of movement and neurocognitive adverse events (MNTs). Other assessments included pharmacokinetic (PK) analyses (Cmax and Tmax of CAR+ T-cell transgene levels in blood), levels of cytokine release syndrome (CRS)-related cytokines (e.g., IL-6) over time, peak levels of cytokines by response and CRS, association of cytokine levels with immune effector cell-associated neurotoxicity syndrome (ICANS), and CAR+ T cell CD4/CD8 ratio by response, CRS, and ICANS. Results: As of January 2022 (median follow-up: 17.1 months [range: 3.3-23.1]), cilta-cel was administered to 20 patients (male: 65%;median age: 60 years [range: 38-75]). Median number of prior LOT was 2 (range: 1-3);median time since MM diagnosis was 3.5 years (range: 0.7-8.0). 95% of patients were refractory to their last LOT;40% were triple-class refractory. Overall response rate was 95%, with 90% of patients achieving ≥complete response and 95% achieving ≥very good partial response. Median time to first response was 1.0 month (range: 0.7-3.3);median time to best response was 2.6 months (range: 0.9-13.6). All MRD-evaluable patients (n=16) achieved MRD negativity at 10-5. Median duration of response was not reached. The 12-month progression-free survival rate was 75% and the 12-month event-free rate was 79%. CRS occurred in 95% of patients (grade 3/4: 10%), with a median time to onset of 7 days (range: 5-9) and median duration of 3 days (range: 2-12). 30% of patients had neurotoxicity (5 grade 1/2 and 1 grade 3/4). ICANS occurred in 3 patients (15%;all grade 1/2);1 patient had facial paralysis (grade 2). No MNTs were observed. 1 death due to COVID-19 occurred and was assessed as treatment-related by the investigator;2 deaths due to progressive disease and 1 due to sepsis (not related to treatment) also occurred. Based on preliminary PK analyses of CAR transgene by qPCR, peak expansion of CAR-T cells occurred at day 10.5 (range: 8.7-42.9);median persistence was 153.5 days (range: 57.1-336.8). Summary/Conclusion: A single cilta-cel infusion led to deepening and durable responses at this longer follow-up (median 17.1 months) in patients with MM who had 1-3 prior LOT and were len-refractory. Follow-up is ongoing. We will present updated and detailed PK, cytokine, and CAR-T subset analyses as well as clinical correlation to provide novel insights into biological correlates of efficacy and safety in this difficult-to-treat patient population, which is being further evaluated in the CARTITUDE-4 study (NCT04181827;enrollment concluded).