Outpatient program safely desensitizes patients to chemotherapy

Key takeaways:

• Percentages of patients who experienced breakthrough reactions decreased from 70% to 52% and then 43%.
• Percentages of patients who completed treatment increased from 20% to 26% and then 36%.

SAN ANTONIO — An interdisciplinary program increased the number of patients safely desensitized to chemotherapy treatment, according to data presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting.

“We know that desensitization allows patients to continue on preferred or first-line chemotherapy safely after hypersensitive reaction,” Rose Monahan, MD, MS, a second-year fellow in the division of pulmonary, critical care, allergy and sleep medicine in the department of medicine at the University of California, San Francisco (UCSF), said during her presentation.

But desensitization is resource-intensive, Monahan continued, often requiring stays in the ICU and care coordination with nursing and pharmacy.

“We wanted to improve access to desensitization and allow this procedure to be performed safely in outpatient settings, so we implemented a multidisciplinary desensitization program here at UCSF,” Monahan said.

Between March and June 2020, a work group including pharmacists, nurses, oncologists, coordinators and allergists met to standardize desensitization workflows. Also, the group held weekly multidisciplinary care coordination rounds as well as quality review and process improvement meetings.

This team now oversees desensitization at outpatient infusion centers and inpatient units located at three separate hospital facilities, Monahan said.

The researchers assessed data from July 2019 through the end of June 2020, which was before the program was implemented (10 patients; 32 desensitizations); year 1, which was from July 2020 through June 2021 (23 patients; 102 desensitizations); and year 2, from July 2021 through June 2022 (42 patients; 148 desensitizations).

The researchers called the increases in percentages of outpatient desensitization cycles from pre-implementation to year 1 (P < .001) and from pre-implementation to year 2 (P < .001) significant.

“It’s important to note that this was not associated with significant increases in the percentages of desensitizations that had breakthrough reactions,” Monahan said.

Desensitization rates included 10% of patients in the pre-implementation period, 78% in year 1 and 78% in year 2. Meanwhile, breakthrough reaction rates included 70% in the pre-implementation period, 52% in year 1 and 43% in year 2.

Although no patients experienced an advance in protocol in the pre-implementation period, 26% of those in year 1 and 33% of those in year 2 saw their protocols advance. Also, 20% of those in the pre-implementation period, 26% of those in year one and 36% of those in year two completed treatment.

Further, there was a significant decrease in days (± standard deviation) between the initial hypersensitivity reaction from pre-implementation (322 ± 185) to year 1 (102 ± 129; P = .03) and between pre-implementation and year 2 (32 ± 25; P = .01).

During pre-implementation, providers desensitized patients to platinum agents (45%), taxane agents (29%) and rituximab (26%). In year 1, desensitization included platinum agents (53%), taxane agents (1%), rituximab (11%), liposomal doxorubicin (11%) and other monoclonal antibodies (24%).

Desensitizations during year 2 included platinum agents (38%), taxane agents (24%), rituximab (14%), liposomal doxorubicin (1%), carfilzomib (7%), cytarabine (3%) and other monoclonal antibodies (13%).

Based on these results, the researchers concluded that the program succeeded in increasing the number of patients treated as well as the number of safely performed desensitizations.

“The goal of allowing outpatient desensitization also was achieved and, importantly, outpatient desensitization saved at least 187 ICU admission days over 2 years and did not lead to increased breakthrough reactions,” Monahan said.

The researchers noted a slight increase in the rate of outpatient desensitizations from year 1 to year 2, but they attributed this increase to increased patient complexity.

“The program expanded with more referrals for patients who had severe initial hypersensitivity reactions who would not have been referred to our program or to our allergy team before this program had been implemented,” Monahan said.

The lack of change in the percentage of patients who were able to move to outpatient treatment between years 1 and 2 supported this conclusion, she continued.

Additionally, the researchers said the program minimized delays in care and enabled more patients to continue and complete full courses of treatment, adding that multidisciplinary care coordination is essential to safe outpatient desensitization.

“These findings support the multidisciplinary care team as an important aspect of a safe desensitization program and that outpatient drug desensitization is a safe and effective method to keep patients on first-line therapies,” Monahan said.