Study design
This multicenter, phase II trial aimed to investigate the efficacy and safety of triplet antiemetic therapy with PALO, APR, and OLN in patients scheduled to undergo HEC as their initial treatment for malignant tumors, specifically breast tumors.
This study was a collaborative effort involving eight domestic institutions. Approval for this research was obtained from the ethics review committees at the Cancer Institute Hospital of JFCR and each participating facility. This study was registered with the University Hospital Medical Information Network (UMIN) in Japan with the registration number UMIN 000038644. In addition, an independent Data and Safety Monitoring Committee oversaw the monitoring of efficacy and safety throughout this clinical trial.
Patient selection
The phase II trial was conducted from July 2019 to June 2022. Patients scheduled to undergo initial HEC treatment for breast cancer were enrolled.
Other eligibility criteria included age 20 years or older, plans for the administration of first-line chemotherapy at standard doses, no restriction on treatment history, and Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0–2. The eligible regimens were as follows: AC (doxorubicin + cyclophosphamide, including dose-dense AC), EC (epirubicin + cyclophosphamide, including dose-dense EC), CAF (cyclophosphamide + doxorubicin + 5-fluorouracil), FEC (5-fluorouracil + epirubicin + cyclophosphamide), and TAC (docetaxel + doxorubicin + cyclophosphamide, with the condition that dexamethasone was not used as pre-medication before docetaxel).
Patients were required to have sufficient organ function, with the following results within the two weeks preceding study registration: alanine aminotransferase less than 100 IU/L; aspartate aminotransferase less than 100 IU/L; total bilirubin concentration less than 2.0 mg/dL; and creatinine clearance calculated by the Cockcroft–Gault formula of 55 mL/min or more. Written, informed consent was obtained from all patients. The exclusion criteria for this study were as follows: history of allergy to the drugs and similar compounds used in this study; steroid drugs, excluding inhaled and topical steroids; evident vomiting symptoms, such as with brain metastasis or severe gastrointestinal passage disorders; symptomatic ascites or pleural effusion requiring therapeutic puncture; gastrointestinal passage disorders, such as gastric outlet obstruction or intestinal obstruction; seizure disorders requiring treatment with antiepileptic drugs; currently receiving adrenaline or pimozide; started treatment with strong opioid drugs within the 48 h before registration; abdominal or pelvic radiotherapy within the 6 days before registration or planned to receive it within 6 days after initiating anticancer drug administration; regular use of antiemetic drugs with antiemetic effects other than the investigational drug; pregnant, lactating, or potentially pregnant women or patients not intending to use contraception; diabetes mellitus treated with antidiabetic drugs or an HbA1c (NGSP) level of 6.5% or higher (6.1% or higher for JDS) within the last 28 days before registration; smoking regularly, although eligible if they quit smoking 1 week before registration; difficulties performing operations such as electronic data capture (EDC) input; or deemed unsuitable for this trial by the principal investigator for other reasons.
Treatment schedule
All eligible patients were administered PALO 0.75 mg (intravenous injection 30 min before the start of chemotherapy), OLN 5 mg (oral administration once daily at bedtime from day 0 to day 4), and APR (oral administration of 125 mg 60 min before the start of chemotherapy and 80 mg orally on the morning of day 2 and of day 3) or fosaprepitant (intravenous injection of 150 mg 60 min before the start of chemotherapy). If nausea, vomiting, or retching occurred within 120 h after chemotherapy and at the patient’s request, additional rescue antiemetic medication was allowed for these symptoms. Rescue antiemetic medications, such as domperidone or metoclopramide, were administered by healthcare providers at each facility according to the study protocol. Because OLN has the side effect of sedation, it is preferable to administer it after dinner or before bedtime to avoid daytime drowsiness or dizziness. However, when not using DEX, there is a possibility of inadequate control if OLN is administered after dinner or before bedtime on the first day of chemotherapy. In addition, it has been suggested that the incidence of acute-phase CINV is higher than that of delayed-phase CINV in AC/EC therapy [15]. Therefore, to expect sufficient effects from the first day, considering the half-life (approximately 28 h) of OLN, OLN was administered before bedtime on the day before chemotherapy. Furthermore, it has been suggested that pre-chemotherapy insomnia affects the onset of CINV [16], and taking medication from the day before treatment starts is also considered rational for avoiding insomnia.
Assessment
The chemotherapy targeted in this study was administered in outpatient settings. Therefore, as specified in the research protocol, all patients had episodes of nausea, vomiting, and the use of rescue medication meticulously recorded using EDC for 120 h after chemotherapy. The data center is located in the Department of Clinical Assessment, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan. Enrolment, data collection, and monitoring were performed using the EDC system Viedoc me (Viedoc Technologies). Data entry to the electronic case report form was performed by investigators using EDC at each site. Patient-reported outcome (PRO) data were collected electronically from patients through an electronic tablet device. No personally identifiable information was entered into the EDC, and the data center did not collect personal information.
Rescue antiemetic medications such as metoclopramide, domperidone, alprazolam, and dexamethasone were prescribed on the day of chemotherapy or before, following the usual procedures at each facility. In addition, adverse events were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and Patient-Reported Outcomes version of the CTCAE (PRO-CTCAE) version 1.0. Patients recorded predetermined PRO-CTCAE items (constipation, diarrhea, loss of appetite, hiccups, insomnia, and drowsiness) in the EDC on the day before treatment initiation and on the 7th day after treatment initiation, as outlined in the research protocol. In addition, this study adopted “composite grading” in the PRO-CTCAE [17].
Outcome measures
The primary endpoint of this study was the total control (TC) rate of nausea and vomiting throughout the overall phase (0-120 h after chemotherapy), defined as the absence of nausea, vomiting, and the use of rescue medication. Secondary endpoints included the TC rate during the acute phase (0–24 h after chemotherapy) and the delayed phase (24–120 h after chemotherapy), CR of vomiting (defined as no vomiting episodes and no use of rescue medication), complete control (CC) of nausea and vomiting (defined as no vomiting episodes, no use of rescue medication, and no moderate or severe nausea), and the proportions of “no nausea” during the acute phase, delayed phase, and overall phase. The severity of nausea was measured on a 4-point Likert scale (0, no nausea; 1, mild; 2, moderate; 3, severe) [18]. The other secondary endpoints included time to treatment failure (TTF; defined as the time to the first vomiting episode or administration of rescue medication) and treatment-related adverse events.
Statistical analysis
The TC rate of the overall phase with chemotherapy, using the standard antiemetic therapy of PALO, APR, and DEX, was reported as 23.2% in a Phase III trial conducted in Japan [12]. In addition, a Phase III trial investigating a four-drug combination antiemetic therapy, which included adding OLN to PALO, APR, and DEX, was conducted outside Japan. The proportion of “no nausea” in the overall phase was reported to be 37.3%, showing an improvement of 15.4% compared with the non-OLN combination group [13]. In Japan, although large-scale trials implementing four-drug combination antiemetic therapy targeting anthracycline-based chemotherapy and cyclophosphamide have not been conducted, observational studies with 92 patients reported a CC rate of approximately 40%, showing an improvement of approximately 10% compared with the non-OLN combination group [19]. According to these reports, the threshold TC rate in the overall phase was set at 23%, with an expected TC rate of 38%, a one-sided significance level (α error) of 0.025, and power of 80%, resulting in a required sample size of 74 cases. In this trial, the administration of OLN before bedtime on day 0 was likely to be performed by the patients themselves at home, raising concerns about medication non-adherence. Therefore, considering a dropout rate of approximately 20%, the target registration sample size was set at 89.
For the primary endpoint, the TC rate during the overall phase, along with its 95% confidence interval, was calculated. In addition, a one-sided binomial test was conducted to verify the null hypothesis that the TC rate is less than 23% and the alternative hypothesis that it is greater than or equal to 23%. The significance level for the one-sided test was set at 2.5%. For secondary endpoints, the number and proportion, along with the 95% confidence interval, were calculated for binary data according to the characteristics of the data. For survival time data, the number of events and censored events were calculated, and survival curves were estimated using the Kaplan–Meier method. Furthermore, the 25th percentile, median, 75th percentile values, and 95% confidence interval for the time to event occurrence based on the Kaplan–Meier method were estimated.