Chimeric antigen receptor (CAR) T-cell therapy is a type of cancer immunotherapy where patients’ T-cells are collected and genetically modified to produce chimeric antigen receptors that recognize specific targets on cancer cells, allowing these T-cells to locate and destroy the cancer cells.

CAR T-cell therapy shows promising results in treating relapsing or refractory B-cell lymphomas. To explore the risks associated with CAR T-cell therapy, researchers from Juntendo University, Japan, including Professor Jun Ando, ​​Professor Miki Ando, ​​and Dr. Erina Hosoya, conducted a study that was in Haematological on October 17, 2024.

Dr. Hosoya, the study’s lead author, says, “We conducted a single-center, retrospective analysis of 59 patients with relapsed/refractory B-cell lymphoma enrolled for CAR T-cell therapy with tisagenlecleucel (tisa-cel) between September 2020 and September 2023. .

“Forty-one study patients (38 with diffuse large B-cell lymphoma (DLBCL) and three with follicular lymphoma (FL)) received an infusion of tisa-cel. Response assessments were completed in 37 patients with DLBCL and one with FL.”

The team tracked overall survival (OS) and progression-free survival (PFS) over 12 months, finding OS at 73.8% and PFS at 49.6%. Safety monitoring showed that 30 out of 41 patients who received tisa-cel developed cytokine release syndrome (CRS), an inflammatory side effect.

Of these, 14 patients had more severe CRS (grade 3 or higher) and also tended to receive higher doses of CAR-positive cells, leading to earlier fevers compared to those with milder (grade 1 or 2) CRS.

The researchers identified 11 laryngeal edemas in patients as a serious and previously unrecognized side effect of CAR T-cell therapy. Initially thought to affect only those with neck tumors, it was found in all patients, regardless of tumor location. Intensive care and airway management were provided due to the obstruction caused by the edema. This condition typically developed within 3.4 days post-infusion and resolved within 14 days for all patients.

Dr. Hosoya says, “Although a few case reports of laryngeal edema with tisa-cel treatment for B-cell lymphoma have appeared, the mechanism of this phenomenon is still unknown and no established management guidelines exist despite the major risk of life-threatening airway obstruction. We, therefore, assessed risk factors for the occurrence of laryngeal edema and the influence of steroid treatment on both CAR T-cell expansion and clinical outcome.”

The research team identified a key risk factor for laryngeal edema—patients who experienced this condition had a significantly higher number of CAR-positive cells infused (4.0 x 10⁸ vs. 3.3 x 10⁸They found that infusions with more than 3.4 x 10⁸ CAR-positive cells could predict the risk of laryngeal edema.

Additionally, the CAR T-cells from patients with laryngeal edema contained a higher proportion of effector T-cells compared to those without edema.

Sharing another interesting observation from the study, Dr. Hosoya says, “Our impression clinically was that the frequency of laryngeal edema after tisa-cel infusion rose in the summer of 2022. So, we attempted to coordinate the date of tisa-cel manufacture with the occurrence of laryngeal edema.”

This observation was a result of the higher numbers of CAR-positive cells in products manufactured after June 2022 than in those manufactured before June 2022.

Based on these observations from the study, the team of researchers concludes that using steroids, such as dexamethasone, could prove effective for early management of laryngeal edema. They found that administering steroids provided relief to patients without reducing the effectiveness of CAR T-cell therapy.

In summary, these findings highlight the serious adverse effects of tisa-cel therapy, its associated risk factors, and management strategies for improving patient safety and treatment experiences. Concluding optimistically, Dr. Hosoya says, “We believe that our analyzes encompass both efficacy and safety with tisa-cel therapy in real-world settings.”

Provided by Juntendo University Research Promotion Center