NEPA- and olanzapine-based regimens similarly effective at preventing CINV in early BC

In a post hoc analysis of two prospective studies, netupitant/palonosetron (NEPA) combined with dexamethasone has demonstrated similar efficacy vs a quadruplet regimen of olanzapine, aprepitant, ondansetron, and dexamethasone in preventing chemotherapy-induced nausea and vomiting (CINV) in Chinese women with early breast cancer (BC) receiving doxorubicin/cyclophosphamide (AC) in Hong Kong.

Optimal antiemetic prophylaxis is important for improving treatment completion rate and maintaining patients’ quality of life (QoL). A previous systematic review and meta-analysis showed that NEPA- and olanzapine-based regimens may be more effective than conventional triplet therapy in preventing CINV. [Oncologist 2019;24:e347-e357] However, there has been a lack of direct comparison of effectiveness between NEPA- and olanzapine-based regimens.

Researchers from the Prince of Wales Hospital and Princess Margaret Hospital in Hong Kong retrospectively evaluated CINV control and QoL in early BC patients receiving AC chemotherapy using relevant data from two prospective studies conducted in 2017–2019. A total of 120 patients were included, with 60 patients receiving NEPA (netupitant 300 mg/palonosetron 0.50 mg) and dexamethasone (12 mg) before chemotherapy on day 1 of every AC cycle, followed by dexamethasone (4 mg BID) on days 2 and 3. The remaining 60 patients received olanzapine (10 mg), aprepitant (125 mg), dexamethasone (12 mg), and ondansetron (8 mg) before chemotherapy on day 1 of every AC cycle, followed by ondansetron (8 mg) 8 hours after chemotherapy. Aprepitant 80 mg/day was administered on days 2 and 3, with olanzapine 10 mg/day administered on days 2–5. [Hong Kong Med J 2023;29:49-56]

All NEPA-treated patients (median age, 56.0 years; stage II BC, 66.7 percent; adjuvant AC, 70 percent) and 93.3 percent of olanzapine-treated patients (median age, 54.5 years; stage II BC, 63.3 percent; adjuvant AC, 80 percent) completed four AC cycles. At baseline, 35.0 percent of NEPA-treated patients and 16.7 percent olanzapine-treated patients had a history of motion sickness.

In the first AC cycle, similar proportions of patients in the NEPA and olanzapine groups reported complete response (defined as no vomiting or nonuse of rescue medications) in the acute phase (<24 hours; 70.0 percent vs 70.0 percent; p=1.0000), delayed phase (24–120 hours; 85.7 percent vs 92.9 percent; p=0.1636), and overall phase (<120 hours; 60.0 percent vs 65.0 percent; p=0.5716) after chemotherapy. The median time to first vomiting was not reached in either group.

Compared with the NEPA group, significantly more patients in the olanzapine group did not require rescue medications in the acute phase (85.0 percent vs 96.7 percent; p=0.0225) and overall phase (76.7 percent vs 91.7 percent; p=0.0244), and had no significant nausea (78.3 percent vs 91.7 percent; p=0.0408) in the overall phase of the first AC cycle.

In contrast, the NEPA group achieved a significantly higher rate of total control (defined as no vomiting, nonuse of rescue medications, and visual analogue scale of nausea severity <5 mm) than the olanzapine group in the overall phase of cycle 3 (73.3 percent vs 55.4 percent; p=0.0430) and cycle 4 (75.0 percent vs 54.4 percent; p=0.0195), as well as in the acute phase of cycle 2 (81.7 percent vs 59.6 percent; p=0.0087) and cycle 4 (86.7 percent vs 63.2 percent; p=0.0032).

QoL assessed after the first cycle showed no significant differences in the total score, nausea domain, and vomiting domain of the self-reported Functional Living Index-Emesis questionnaire between the NEPA and olanzapine groups.

“These findings do not conclusively support the superiority of either [olanzapine-based or NEPA-based] regimen in early BC patients receiving AC chemotherapy,” the investigators concluded.