Outpatient rapid drug desensitization to chemotherapy: A multidisciplinary approach to transition encounters out of the ICU.

73 Background: Hypersensitivity reactions (HSR) to antineoplastics pose significant challenges in cancer treatment. These reactions can often be managed via rapid drug desensitization (RDD), or introduction of the drug at increasing doses to promote temporary immune tolerance. RDD requires dedicated monitoring and has historically been limited to the intensive care unit (ICU), where bed availability is limited. Emerging data suggests it may be safe and effective to move RDD outpatient. We implemented a multidisciplinary team of allergists, oncologists, and pharmacists to develop a new workflow to transition RDD from the ICU to the oncology stepdown unit (SDU) and then the outpatient infusion center. Methods: We examined the data of eligible patients undergoing RDD at Columbia University Medical Center from 2022-2024, before and after implementation of the new workflow. Included patients had a cancer diagnosis and a suspected HSR during antineoplastic infusion. HSRs were reviewed by an allergist and classified as mild (absence of chest pain, blood pressure changes, dyspnea, oxygen desaturation, or throat tightness) or severe (≥1 of these). Data collected included the oncologic diagnosis, culprit agents, cycle number at initial HSR, date(s) and location(s) of RDD, and severity and management of breakthrough reactions. A two-tailed z-test assessed differences between groups. Results: During the study period, 26 patients underwent 102 RDDs. Mean age at initial RDD was 57.7 years (SD 12.5), and 69.2% were female. The most common diagnoses were pancreatic cancer (23.1%) and colorectal cancer (15.4%); the most common culprit for an initial HSR was oxaliplatin (42.3%); and 34.6% of the initial HSRs were classified as mild, 65.4% as severe. Forty-six total RDDs were performed prior to the new workflow and 56 after. Prior, 16/46 (34.8%) encounters took place in the ICU, 24/46 (52.2%) on SDU, and 6/46 (13.0%) outpatient. After the new workflow, zero took place in the ICU, 19/56 (33.9%) on SDU, and 37/56 (66.1%) outpatient, demonstrating a significant decrease in ICU utilization (p < 0.00001). While undergoing RDD, 22 total breakthrough reactions occurred out of 102 total encounters; 21 were classified as mild (most commonly cutaneous reactions such as urticaria), while one was severe. In 99/102 (97.1%) encounters, the RDD protocol was successfully completed. There was no difference in frequency of breakthrough reaction (p = 0.31) or RDD completion after breakthrough (p = 0.67) between the workflow groups. Conclusions: Our data supports that RDD is an effective method for achieving temporary tolerance and safely administrating antineoplastic treatment that otherwise would need to be discontinued. By implementing a standardized process for HSR identification and treatment we safely transitioned out of the ICU, which may optimize resource utilization, access to care, and cost reduction.