Objectives To retrospectively evaluate the safety and efficacy of an outpatient 12-step carboplatin desensitization regimen in patients with prior carboplatin HSR.

Methods Patients with a history of carboplatin HSR undergoing carboplatin desensitization for mullerian cancer were included. Following consultation with a desensitization specialist, patients were premedicated for 3 days (prednisone 40 mg, montelukast 10 mg) and immediately prior to carboplatin (dexamethasone, antihistamine-1 and antihistamine-2 antagonists). Carboplatin was administered in 12 steps under dedicated nursing supervision: Bag1 (1% dose), Bag2 (2.5% of dose), Bag3 (96.5% of dose) were each given in 4 incremental steps. Planned infusion time for steps 1–11 was 15 minutes/step and step 12 was administered at 75ml/hour.

Results 30 patients received carboplatin desensitization between 12/2016–01/2019. During their prior HSR 5/30 (16%) had required epinephrine. 19/30 (63%) were seen by an allergist prior to desensitization. 24/30 (80%) received ≥ 2 desensitization cycles with median of 3 (range 1–8). During desensitization 11/30 (37%) had breakthrough HSR; 9 of these 11 (81%) were able to receive additional cycles. 2/30 (7%) required epinephrine with 1 patient (3%) transferred to urgent care. No patient required admission for HSR. Reasons for treatment discontinuation were: completed planned treatment (12/30, 40%), disease progression (11/30, 37%), and HSR (5/30, 17%). Median time in chemo unit was 504 minutes (range 335–630).

Conclusions 37% had breakthrough HSR despite the 12-step desensitization; however, the majority was able to receive additional platinum desensitization. Our data suggest that outpatient carboplatin desensitization is feasible but repeated HSR can occur. Dedicated nursing care and access to desensitization specialists are required.