Background Hormone receptor (HR)-positive breast cancer is a disease for which no immune checkpoint inhibitors have shown promise as effective therapies. Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors synergistically increased the effectiveness of antiprogrammed cell death protein-1 (anti-PD-1)/programmed death-ligand 1 (PD-L1) antibodies in preclinical studies. Methods This non-randomized, multicohort, phase II study evaluated the efficacy and safety of the anti-PD-1 antibody nivolumab 240 mg administered every 2 weeks in combination with the CDK4/6 inhibitor abemaciclib 150 mg twice daily and either fulvestrant (FUL) or letrozole (LET) as a first-line or second-line treatment for HR-positive HER2-negative metastatic breast cancer. The primary end point was the objective response rate (ORR), and secondary end points were toxicity, progression-free survival, and overall survival. Blood, tissue, and fecal samples were collected at multiple points for correlative studies to evaluate immunity biomarkers. Results From June 2019 to early study termination due to safety concerns on July 2020, 17 patients were enrolled (FUL: n=12, LET: n=5). One patient with a prior treatment history in the FUL cohort was excluded. ORRs were 54.5% (6/11) and 40.0% (2/5) in the FUL and LET cohorts, respectively. Treatment-emergent (TE) adverse events (AEs) of grade ≥3 occurred in 11 (92%) and 5 (100%) patients in the FUL and LET cohorts, respectively. The most common grade ≥3 TEAEs were neutropenia (7 (58.3%) and 3 (60.0%) in the FUL and LET cohorts, respectively), followed by alanine aminotransferase elevation (5 (41.6%) and 4 (80.0%)). One treatment-related death from interstitial lung disease occurred in the LET cohort. Ten patients developed liver-related grade ≥3 AEs. Liver biopsy specimens from 3 patients showed hepatitis characterized by focal necrosis with predominant CD8+ lymphocyte infiltration. Marked elevation of tumor necrosis factor-related cytokines and interleukin-11, and a decrease in peripheral regulatory T cells (Tregs), were observed in patients with hepatotoxicity. These findings suggest that treatment-related toxicities were immune-related AEs likely caused by proinflammatory cytokine production and suppression of Treg proliferation due to the addition of abemaciclib to nivolumab therapy. Conclusions Although the combination of nivolumab and abemaciclib was active, it caused severe and prolonged immune-related AEs. Trial registration number JapicCTI-194782, jRCT2080224706, UMIN000036970.

Nausea and vomiting are common adverse events associated with trastuzumab deruxtecan (T-DXd). We evaluated the efficacy of an olanzapine-based triplet regimen for preventing nausea and vomiting in patients receiving first cycle T-DXd. This multi-institutional, randomized, double-blind, placebo-controlled (ERICA) phase II study enrolled patients with HER2-positive/HER2-low metastatic breast cancer receiving their first cycle of T-DXd. Patients were randomized to olanzapine 5 mg or placebo once daily (1:1 ratio) from Day 1 to 6, plus a 5-hydroxytryptamine type 3-receptor antagonist (5-HT₃RA) and dexamethasone 6.6 mg intravenously or 8 mg orally on Day 1. The total observation period was 504 hours (21 days) from the first T-DXd administration. The primary endpoint was complete response (CR), defined as no emetic events and no rescue medications, in the delayed phase (24-120 hours post-T-DXd), with the type I error rate of 0.2 (one-sided) for the comparison. Secondary endpoints included no nausea rate in the delayed and persistent phases (120-504 hours), adverse event by CTCAE and PRO-CTCAE. In total, 168 patients were enrolled at 43 sites in Japan (Nov 2021-Sep 2023) with 162 patients (olanzapine, n = 80; placebo, n = 82) included in the per protocol set. The primary endpoint was met as the delayed phase CR rate was significantly greater with olanzapine than placebo (70.0% versus 56.1%, P = 0.047). Efficacy was maintained in the persistent phase (63.9% versus 44.4%). No nausea rate was also greater with olanzapine (delayed phase: 57.5% versus 37.8%; persistent phase: 51.4% versus 31.9%). CR rates in the delayed phase favored olanzapine across subgroups. Appetite loss was also decreased with olanzapine. Hyperglycemia and somnolence were mostly of low-grade severity. Olanzapine 5mg for 6 days with 5-HT₃RA and dexamethasone appears effective for T-DXd-treated patients to prevent delayed and persistent nausea and vomiting.

Antibody–drug conjugates (ADCs) are an emerging class of anticancer therapy that combines the specificity and long circulation half-life of monoclonal antibodies with the cytotoxic potency of the payload connected through a chemical linker. The optimal management of toxicities is crucial for improving quality of life in patients undergoing ADCs and for avoiding improper dose reductions or discontinuations. This article focuses on the characteristics and management of nausea and vomiting (NV) induced by three ADCs: trastuzumab deruxtecan (T-DXd), sacituzumab govitecan (SG), and datopotamab deruxtecan (Dato-DXd). We summarize the proposed mechanism of NV, clinical study data on NV, and recommendations from clinical guidelines. We also discuss three prospective studies evaluating prophylactic antiemetic therapy in patients receiving T-DXd, along with future perspectives.

Background: Patients with early recurrence of hormone receptor (HR)-positive, HER2-negative (HR+/HER2−) breast cancer have a poor prognosis. We aimed to identify clinical and pathological risk factors for recurrence within three years after surgery of HR+/HER2− breast cancer. Methods: We retrospectively reviewed clinical data of patients with stage II–III HR+/HER2− breast cancer who received adjuvant endocrine therapy from January 1, 2012 to January 1, 2017 at five institutions. Using univariable and multivariable analyses, we determined risk factors for invasive disease-free survival (IDFS). A nomogram was generated using variables from the multivariable analysis to predict 3-year IDFS rate. Results: A total of 2732 patients were analyzed, with a median follow-up of 7.1 years. The 3-year IDFS rate was 92.1%. Multivariable analysis for IDFS revealed significant risk factors: age (40–69 vs. 20–39 years: HR 0.69, p = 0.011), nuclear grade (Grade 2 vs. Grade 1: HR 1.66, p < 0.001; Grade 3 vs. Grade 1: HR 1.64, p < 0.001), vascular invasion (Yes vs. No: HR 1.36, p = 0.027), pathological invasive tumor size (2–5 cm vs. < 2 cm: HR 1.75, p < 0.001; ≥ 5 cm vs. < 2 cm: HR 2.07, p < 0.001), number of positive lymph nodes (≥ 4 vs.0: HR 1.70, p < 0.001), and neoadjuvant chemotherapy (NAC) (Yes vs. No: HR 2.41, p < 0.001). The nomogram’s concordance index was 0.68. Conclusion: Younger age, nuclear grade, vascular invasion, tumor size and number of lymph node metastases were identified as independent risk factors for early recurrence. Patients whose physicians chose NAC had worse survival than those who did not.

Asai-Sato M, et al. J Gynecol Oncol. 2022 Oct;34:e10. https://doi.org/10.3802/jgo.2023.34.e10

Introduction: The antibody-drug conjugate trastuzumab deruxtecan (T-DXd) has led to a change in the clinical management of breast cancer. Nausea and vomiting are the most common adverse events of T-DXd, which cannot be completely alleviated by standard prophylactic regimens. Olanzapine is particularly effective in preventing delayed nausea caused by chemotherapy. In this study, we will evaluate the efficacy of olanzapine in managing persistent nausea and vomiting during T-DXd treatment. Methods and analysis: The ERICA study is a multicentre, placebo-controlled, double-blind, randomised phase II study with the aim to evaluate the antiemetic effects of the prophylactic olanzapine (5 mg orally, on days 1–6) or placebo combined with a 1,5-hydroxytryptamine-3 (5-HT ₃ )–receptor antagonist and dexamethasone in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer undergoing T-DXd treatment. For a period of 22 days from the day of T-DXd treatment, patients will document their experience in an electronic symptom diary daily during observational periods. The primary endpoint is the complete response rate, defined as no vomiting and no rescue medications during the ‘delayed phase’ of 24–120 hours post-T-DXd administration. In addition, we define 120–504 hour as the ‘persistent phase’ and 0–504 hours as the ‘overall phase’ for secondary endpoint analysis. We have estimated that a total sample size of at least 156 patients is needed to allow a power of 80% at a one-sided significance level of 20% in this study. The target sample size is set to 166 to account for possible case exclusions. Ethics and dissemination: The study protocol is approved by the West Japan Oncology Group protocol review committee and the SHOWA University Clinical Research Review Board. The study results will be presented at international conferences and published in a peer-reviewed journal. Trial registration number: jRCTs031210410.