Cytokine release syndrome among acute lymphocytic leukemia adults undergoing treatment with blinatumomab in the United States.

e18518 Background: Blinatumomab is a bispecific antibody that works as a T-cell engager and can trigger CD3-positive T cells to attack CD19-positive B cells. It is commonly used for patients with acute lymphoblastic leukemia (ALL). One of the main side effects of Blinatumomab therapy is cytokine release syndrome(CRS), which can present with a plethora of symptoms based on its grading. This study used a national sample to investigate the prevalence of CRS among ALL patients treated with Blinatumomab and associated factors. Methods: For this study, we identified admissions of ALL patients who received Blinatumomab. Cases were adults of ages 18 or older with an ICD-10 code “C91.0x” (ALL) as well as a code of “XW03351” or “XW04351”(Blinatumomab). CRS was identified as D89.83x. Since the ICD-10 code of CRS was available from October 2020 onwards, and the ICD-10 codes for Blinatumomab were terminated in October 2021, we restricted our sample to cases treated between October 2020 and September 2021. We compared the baseline demographics of patients with CRS vs. without CRS and their hospital burden. Results: Out of the 1380 adult cases with ALL who received Blinatumomab, 210(13.2%) reported events of CRS. Around 52.4% of all CRS cases were Grade 1, while 19.0% were Grade 2, 7.1% were Grade 3, none were Grade 4 or 5, and 23.8% were unspecified. The mean age of grade 1 was 48.82 years, grade 2 was older at 57.50 years, grade 3 was at 48.00 years, unspecified groups were 48.52 years, and patients without CRS had a mean age of 48.33 years(p<0.01). The majority of the patients were racially classified as Whites in the CRS(61.0%) and non-CRS groups(56.6%, p<0.01). The sex of the patients between the CRS and non-CRS groups did not differ, as 52.4% of patients with CRS were males, while it was 57.5% in the non-CRS cohort(p=0.167). Around 52.4% of CRS patients were insured through private coverages, while it involved 48.6% of the non-CRS cases, with no statistically significant differences(p=0.408). Their overall Charlson Comorbidity Index (CCI) scores were also comparable(2.78 in the non-CRS group vs. 2.71 among CRS patients, p=0.463). In general, patients who experienced CRS stayed hospitalized longer, with a mean stay of 10.14 days(vs. 7.33 days, p<0.01), coupled with a higher hospital charge of $241682(vs. $156313, p<0.01). Conclusions: In our real-world data, 13.2% of ALL cases undergoing Blinatumomab therapy experienced CRS. The most common form of CRS was grade 1, while grade 2 involved an older group. Furthermore, we confirmed that CRS significantly impacted the healthcare burden among such admissions. Oncologists need to establish specific pre-therapy assessments to help stratify at-risk groups, identify and treat cases of CRS early, and emphasize the importance of proactive measures in managing CRS.