Rapid drug desensitization with chemotherapy: when should omalizumab be considered?

Background: All chemotherapy agents have the potential risk of developing hypersensitivity reactions (HSRs). In patients who develop HSRs, rapid drug desensitization (RDD) enables the use of a treatment option that prevents disease progression. If RDD fails to elicit the desired results or in patients with baseline HSRs Brown grades 2-3, omalizumab may also be a treatment option. Our primary aim is to share the demographic and clinical characteristics of our patients who underwent RDD. Our secondary aim is to share our experience with omalizumab during RDD in difficult cases.

Methods: This was a retrospective study of patients with immediate-HSRs to chemotherapeutic (CHT) agents. Initial HSRs were classified as grades 1, 2, or 3 based on severity. Prick/intradermal skin tests were performed with implicated agents. In grade 3 reactions and skin prick test (SPT)-positive patients, a 16-step desensitization was applied. A 12-step desensitization was applied in other patients. In 10 patients, omalizumab was administered for premedication.

Results: The study analyzed data from 80 patients (F/M: 60/20). The number of patients who received different medictions was as follows: carboplatin-23, paclitaxel-22, oxaliplatin-21, dasotaxel-9, etoposide-1, docorubicin-1, pertuzimab-1, paclitaxel+herceptin-1, and bevacizumab+oxaliplatin-1. Inıtıal HSRs were grade 1: 27(%33,7) , grade 2: 30 (%37,5), and grade 3: 23(% 28,7). A total of 22 patients (27.5 %) had atopy based on SPT. Skin tests with implicated agents were done on 78 patients. For the inıtial HSR grades 1, 2, and 3, the number of positive skin test responses was 25/27, 27/29, and 17/22, respectively. A total of 377 RDDs were performed completely, but 22 patients developed 3 reactions during RDD (grade 1: 77.2%, grade 2: 13.6%, and grade 3 9%). All patients received a mean of 4.7 (minimum: 1, maximum: 23) RDDs. There was no statistical difference in the severity of reaction, system involvement, and distribution of symptoms between platinum and taxanes groups. The rate of reaction during RDD was higher in patients receiving platinum compared with taxan. Ten patients received omalizumab before RDD. Initial HSRs were grade 3 in 8 patients; the responsible agent was platinum in 5 patients; and 1 patient developed grade 3 HSR during RDD. In four patients, ınıtıal HSRs were grades 2 and 3, and desensitization was not continued when HSR developed during RDD. A total of 373 successful RDDs were performed.

Conclusions: RDD is a very important treatment applied to patients with immediate-HSRs to CHT agents. Omalizumab facilitated the continuation of chemotherapy in patients with index reaction grades 2-3. It provided an opportunity for 8 of 10 patients with Grade 2-3 severe reactions to continue treatment. In our population, 98.9% (373/377) successful completion of RDDs in all chemotherapy groups demonstrates the safety of this procedure.