32P - Efficacy of olanzapine in the prophylaxis of delayed chemotherapy-induced nausea and vomiting in breast cancer patients receiving dose-dense AC with a steroid-sparing regimen: A single-center pilot study

Background

International guidelines recommend a combination of NK1, 5-HT3 receptor antagonists, and dexamethasone (DEX) as standard antiemetic therapy for patients treated with a doxorubicin and cyclophosphamide (AC) regimen. However, DEX has been associated with several side effects, including diabetes, osteoporosis, and immunosuppression. Additionally, pneumocystis pneumonia, a rare but fatal condition, has been reported, predominantly in patients undergoing the dose-dense AC (ddAC) regimen.

Methods

We recruited 30 patients with Stage I-III breast cancer who received the ddAC regimen. Patients were administered prophylactic olanzapine (OLZ) 5 mg/day on days 1 to 4 in addition to the standard three-drug combination antiemetic regimen, with DEX omitted on days 2 and 3. Nausea/vomiting and drowsiness were evaluated using a 4-point Likert scale questionnaire previously employed in the J-FORCE study, which assessed the efficacy of OLZ 5 mg in high-emetic-risk regimens. The primary endpoint was complete response (CR) rate in the delayed phase (24-120 hours post chemotherapy administration) of the first cycle. Secondary endpoints included the total control (TC) rate of nausea and vomiting, complete control (CC) rate, degree of daytime sleepiness, and quality of life as assessed by EORTC QLQ-C30 Ver.3.

Results

Among the participants, 22 patients (73%) received ddAC as neoadjuvant chemotherapy and 8 (27%) as adjuvant chemotherapy. Median age at the start of treatment was 56 years. CR rates were 73% and 63% in the acute and delayed periods, respectively. TC and CC rates in the acute period were 60% and 73%, whereas those in the delayed period were 36.6% and 63%, respectively. In both periods, 40% of patients experienced moderate or severe sleepiness. Mean scale scores for nausea on the EORTC QLQ-C30 remained within the Minimally Important Difference score level throughout the 4th cycles of treatment.

Conclusions

This prospective pilot study suggests that the addition of OLZ 5mg allows the omission of steroids without a worsening of CINV in patients with ddAC.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.