1049P - Cytokine release syndrome in patients treated with bispecific T cell engagers and bispecific monoclonal antibodies at The Christie: A retrospective study

Background

Cytokine release syndrome (CRS) is one of the most common toxicities related to cell therapies as well as other non- cell therapy immunotherapies. There is a need to further study this adverse event in patients receiving bispecific T cell engagers or monoclonal antibodies. This is a deep dive into the CRS events that occurred over last year in this category of patients.

Methods

This is a retrospective study conducted at The Christie NHS Foundation Trust in which we identified all the CRS events that occurred during the year between Oct 2022-Oct 2023. Patients must be diagnosed with haematological or solid malignancies and must have received treatment with a BiTE or monoclonal bispecific antibody. We reviewed patients clinical data and treatment approaches.

Results

33 events were identified, 32 of them occurred during the first cycle of therapy. Two-thirds of patients received BiTE 82% of events were of grade 1. Only 1 G4 event was identified and unfortunately led to the death of the patient. There was a trend towards significance between combination of immunotherapy with SACT and CRS grade higher than 1 (p=0.056). The most common symptom was fatigue (36%) and fever was the most common sign (30 events). In absence of fever, unexplained hypoxia was accepted to identify an event. Second most common sign was hypoxia which occurred in 17 events however only 5 of which required supplementary oxygen. Inflammatory markers were reviewed, there was CRP increase in 82% of cases, however, was not significantly associated with degree of CRS. Similarly, leucocytosis(45.5%) was not associated with degree of CRS. Ferritin was increased in 1/3 of patients. Despite that positive cultures were only identified in 3 cases, 15 patients were empirically treated with IV antibiotics. Tocilizumab was used in 10 events.

Conclusions

According to this retrospective analysis, cytokine release syndrome in patients treated with BiTEs or bispecific monoclonal antibodies was found to occur during the first cycle and was usually of low grade however mortality was the outcome of the high-grade event that occurred. In many cases, it was difficult to identify the cause of fever and empirical antibiotics were used in almost half of the events.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.