Eriko Tokunaga

Figure S1, Figure S2, Figure S3, Table 1 References.

Purpose: The phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase (AKT) pathway is frequently activated in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, with loss of phosphatase and tensin homolog (PTEN) activity contributing to this activation. Capivasertib is a potent pan-AKT inhibitor, approved in combination with fulvestrant for the treatment of HR-positive/HER2-negative locally advanced/metastatic breast cancer with one or more PIK3CA/AKT1/PTEN tumor alterations. Next-generation sequencing (NGS) is commonly used to identify patients with PIK3CA/AKT1/PTEN tumor alterations. However, the utility of immunohistochemistry (IHC) to identify patients with PTEN-deficient tumors has not been explored in this context. Experimental Design: This exploratory analysis was based on tumor samples collected from patients in the global phase III CAPItello-291 study. Results: PTEN IHC results were obtained for 367 tumor samples, with 70 (19.1%) identified as PTEN deficient by IHC. A total of 346 (94.3%) samples with a PTEN IHC test result also had NGS test results available for PIK3CA/AKT1/PTEN alteration status. When comparing PTEN deficiency by IHC with PTEN alteration status by NGS, the overall, positive, and negative percent agreements were 87.0% (301/346), 71.9% (23/32), and 88.5% (278/314), respectively. Exploratory analysis in patients with PTEN-deficient tumors by IHC (n = 70) showed improved progression-free survival in the capivasertib plus fulvestrant versus placebo plus fulvestrant treatment arm (median 9.3 vs. 3.7 months; hazard ratio: 0.52, 95% confidence interval, 0.28–0.90). Conclusions: These results suggest potential utility for IHC in determining tumor PTEN status in breast cancer and raise the possibility of IHC identifying additional patients who could benefit from treatment with capivasertib and fulvestrant.

Although taxanes are a mainstay treatment for locally advanced or metastatic breast cancer (LABC/MBC), they often impair quality of life (QoL). Treatments that avoid taxane-related QoL deteriorations would be valuable. The JBCRG-M06/EMERALD trial (NCT03264547, UMIN000027938) compared eribulin with a taxane, each combined with trastuzumab and pertuzumab, in patients with human epidermal growth factor receptor type 2 (HER2)-positive LABC/MBC. QoL was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Module C30 (EORTC QLQ-C30) version 3.0. QoL deterioration was defined as a decrease in the Global Health Status (GHS) score by ≥ 10 points (minimum clinically important difference), disease progression, or death. QoL data were available for 210 (of 224 randomized) and 205 (of 222 randomized) patients in the eribulin and taxane groups, respectively. The median (95% confidence interval) time to QoL deterioration was 7.16 (6.28-8.34) months in the eribulin group versus 4.57 (4.17-6.14) months in the taxane group, with a hazard ratio of 0.80 (95% confidence interval 0.65-0.98; log-rank P = 0.08). QoL was maintained at 6 and 12 months in greater proportions of the eribulin group (62.7% and 30.5%) compared with the taxane group (43.5% and 25.5%). GHS scores remained stable over time in the eribulin group. GHS deteriorated between weeks 9 and 27 in the taxane group (i.e. during treatment) with subsequent recovery toward baseline. Eribulin could help avoid the early deteriorations in QoL that occur during taxane therapy and maintain QoL for longer in patents with HER2-positive LABC/MBC receiving trastuzumab and pertuzumab.

PURPOSE: The HER2CLIMB-05 study (ClinicalTrials.gov identifier: NCT05132582 ) is investigating the efficacy and safety of adding tucatinib to trastuzumab and pertuzumab as first-line (1L) maintenance therapy in patients with human epidermal growth factor receptor 2–positive (HER2+) metastatic breast cancer (MBC). METHODS: Patients with centrally confirmed HER2+ MBC without evidence of progression post induction therapy and no or asymptomatic brain metastases (BM) were enrolled. Patients were randomly assigned 1:1 to tucatinib (300 mg) or placebo twice a day combined with trastuzumab/pertuzumab. The primary end point is investigator-assessed progression-free survival (PFS); secondary end points include overall survival (OS), PFS per blinded independent central review, CNS-PFS, and safety. RESULTS: Between March 2022 and July 2024, 654 patients were randomly assigned to tucatinib (n = 326) and placebo (n = 328) arms. All patients were female (median age, 54 years), 69.3% had de novo MBC, 52.6% were hormone receptor–positive, and 12.4% had presence/history of baseline BM. In this primary analysis, PFS was statistically significantly improved with addition of tucatinib versus placebo (hazard ratio, 0.641 [95% CI, 0.514 to 0.799]; P < .0001; median PFS: 24.9 v 16.3 months); a PFS benefit was seen regardless of the presence/absence of BM or hormone receptor status. OS data remain immature. The most common treatment-emergent adverse events (TEAEs) in the tucatinib arm were diarrhea (72.7%), nausea (33.1%), and elevated liver enzymes (ALT: 28.2%; AST: 25.8%), of which 6.1%, 0.9%, 13.5%, and 7.1%, respectively, were grade ≥3. In the tucatinib arm, 13.5% discontinued tucatinib because of TEAEs. CONCLUSION: Tucatinib addition to trastuzumab and pertuzumab demonstrated improvement in PFS with no new safety signals identified and may be an option for 1L maintenance therapy in patients with HER2+ MBC.

Background: Prophylaxis for chemotherapy-induced nausea and vomiting (CINV) in patients receiving highly emetogenic chemotherapy (HEC) is essential. Four-drug antiemetic therapy, consisting of a neurokinin-1 receptor antagonist (NK1RA), a 5-hydroxytryptamine type 3 receptor antagonist (5-HT3RA), dexamethasone (DEX), and olanzapine (OLZ), is currently recommended for HEC. However, the efficacy, optimal dosing schedule, and appropriate dosage of OLZ remain unclear when combined with a highly selective NK1RA, fosnetupitant (FosNTP). Objective: This study aimed to evaluate the efficacy and safety of a four-drug antiemetic regimen including FosNTP and OLZ for prophylaxis of CINV in patients receiving anthracycline-based (neo)adjuvant chemotherapy for early breast cancer (EBC) and to explore outcomes with OLZ dose adjustments in the second cycle. Methods: This single-institution, prospective observational study will enroll 100 patients with EBC who undergo HEC. All patients will receive a four-drug antiemetic regimen consisting of FosNTP, 5-HT3RA, DEX, and the guideline-recommended dose of OLZ administered orally from days –1 to 4. During the second cycle of treatment, OLZ dosing may be adjusted based on tolerability and patient preference. The primary endpoint is the proportion of patients who experienced no nausea during the overall phase (0‐120 h) of the first cycle, as assessed using the daily visual analog scale. A sample size of 86 was calculated to assess the efficacy of the four-drug antiemetic regimen, including OLZ, assuming an expected no nausea rate of 42%, a threshold no nausea rate of 27% based on historical data, 90% power, and a 1-sided significance level of 5.0%. A single-sample z-test with a normal approximation will be used for the analyses. Results: This study was approved by the Ethics Committee of the National Hospital Organization Kyushu Cancer Center, and participant recruitment and data collection commenced in May 2024. As of September 2025, approximately 70 participants have been recruited. Data collection is expected to continue until April 2026, and both data collection and analyses are anticipated to be completed in 2027. Conclusions: This study will provide real-world evidence on the effectiveness and safety of a four-drug antiemetic regimen, including FosNTP and OLZ, in patients receiving anthracycline-based HEC and may inform optimal OLZ dosing strategies.

Editorial Commentary CDK4/6 inhibitors for premenopausal women with hormone receptor-positive/HER2-negative breast cancer; insight from Young-PEARL Eriko Tokunaga

BACKGROUND Prophylaxis for chemotherapy-induced nausea and vomiting (CINV) in patients receiving highly emetogenic chemotherapy (HEC) is essential. Four-drug antiemetic therapy, consisting of a neurokinin-1 receptor antagonist (NK1RA), a 5-hydroxytryptamine type 3 receptor antagonist (5-HT3RA), dexamethasone (DEX), and olanzapine (OLZ), is currently recommended for HEC. However, the efficacy, optimal dosing schedule, and appropriate dosage of OLZ remain unclear when combined with a highly selective NK1RA, fosnetupitant (FosNTP). OBJECTIVE To evaluate the efficacy and safety of a four-drug antiemetic regimen including FosNTP and OLZ for prophylaxis of CINV in patients receiving anthracycline-based (neo)adjuvant chemotherapy for early breast cancer (EBC) and to explore outcomes with OLZ dose adjustments in the second course. METHODS This single-institution, prospective observational study will receive 100 patients with EBC who undergoes HEC. All patients will receive a four-drug antiemetic regimen consisting of FosNTP, 5-HT3RA, DEX, and the guideline-recommended dose of OLZ administered orally from days –1 to 4. During the second course of treatment, OLZ dosing may be adjusted based on tolerability and patient preference. The primary endpoint is the proportion of patients who experienced no nausea during the overall phase (0–120 h) of the first course, as assessed using the daily visual analog scale. A sample size of 86 was calculated to assess the efficacy of the four-drug antiemetic regimen, including OLZ, assuming an expected no nausea rate of 42%, a threshold no nausea rate of 27% based on historical data, 90% power, and a 1-sided significance level of 5.0%. A single-sample z-test with a normal approximation will be used for the analyses. RESULTS This study was approved by the Ethics Committee in March 2024, and participant recruitment and data collection commenced in May 2024. As of September 2025, approximately 70 participants have been recruited. Data collection is expected to continue until April 2026, and both data collection and analyses are anticipated to be completed in 2027. CONCLUSIONS This study will provide real-world evidence on the effectiveness and safety of a four-drug antiemetic regimen, including FosNTP and OLZ, in patients receiving anthracycline-based HEC and may inform optimal OLZ dosing strategies. CLINICALTRIAL UMIN-CTR UMIN000054250; https://www.umin.ac.jp/ctr/

Background: Systemic therapy (ST) is essential for de novo stage IV breast cancer (BC). Stage IV BCs are highly heterogeneous, and it seems inappropriate to treat all de novo stage IV BCs equally. The survival benefit of surgery for primary sites in patients with de novo stage IV BC remains inconclusive. Patients and methods: We investigated 220 patients with clinical de novo stage IV BC. The relationship between primary site surgery and overall survival (OS) was analyzed. Factors such as tumor subtype, timing of surgery, and efficacy of ST were also evaluated. Results: The median follow-up time was 37.9 (0.5–201.7) months. In the total cohort, the median OS of the patients with and without primary site surgery was 70.5 months (95% confidence interval [CI] 58.4–107.3) and 42.7 months (95% CI 35.7–48.8), respectively. The OS was significantly longer in patients who underwent primary site surgery, especially in the hormone receptor (HR) + /HER2- and HER2 + subtypes, but not in the triple-negative subtype. OS prolongation was significant in patients who underwent surgery ≥ 24 months after the first diagnosis and in whom the first-line ST was effective for ≥ 24 months. Primary site surgery was a good prognostic factor in both univariate and multivariate analyses. Conclusions: The OS was significantly longer in patients with de novo stage IV BC who underwent primary site surgery than in those who did not undergo surgery. Our results suggest that the tumor subtypes, efficacy of ST, and timing of surgery influenced the benefits of surgery.

Background: In CAPItello-291, capivasertib–fulvestrant significantly improved progression-free survival (PFS) versus placebo–fulvestrant in the overall and PIK3CA/AKT1/PTEN-altered population with hormone receptor-positive (HR-positive)/human epidermal growth factor receptor 2-negative (HER2-negative) advanced breast cancer. Capivasertib–fulvestrant is approved in Japan for the treatment of patients with one or more tumor biomarker alterations (PIK3CA, AKT1 or PTEN). Here, we report outcomes in the CAPItello-291 subgroup of patients from Japan. Methods: Adults with HR-positive/HER2-negative advanced breast cancer whose disease had relapsed or progressed during or after treatment with an aromatase inhibitor, with or without previous cyclin-dependent kinase 4/6 (CDK4/6) inhibitor therapy, were randomly assigned (1:1 ratio) to receive capivasertib or placebo, plus fulvestrant. The dual primary endpoint was investigator-assessed PFS in the overall and PIK3CA/AKT1/PTEN-altered population. Safety was a secondary endpoint. Results: Of 708 patients randomized in CAPItello-291, 78 were from Japan (37 randomized to capivasertib–fulvestrant and 41 to placebo–fulvestrant). In the Japan subgroup, PFS numerically favored the capivasertib–fulvestrant arm (hazard ratio 0.73; 95% CI 0.40–1.28), consistent with the analysis of PFS in the global population. Similarly, in the Japan subgroup of patients with PIK3CA/AKT1/PTEN–altered tumors, PFS favored the capivasertib–fulvestrant arm (hazard ratio 0.65; 95% CI 0.29–1.39), consistent with the global population. The adverse event profile of capivasertib–fulvestrant in the Japan subgroup was broadly similar to that in the global population; no new safety concerns were identified. Conclusion: Outcomes in the Japan subgroup were broadly similar to those of the global population, supporting the clinical benefit of capivasertib–fulvestrant in treating HR-positive/HER2-negative advanced breast cancer that has progressed on, or after, an endocrine-based regimen.

Background: Breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) is a rare malignancy. Many cases of BIA-ALCL are identified based on the presence of late-onset effusion and/or masses. Importantly, the United States Food and Drug Administration noted that in all cases diagnosed in patients with textured implants, the patients either had a history of mixed implantation of smooth and textured devices or no clinical history was supplied for review. In Japan, the first case of BIA-ALCL was reported in 2019, and we encountered the third case in Japan in December 2021. There have been a total of five cases of BIA-ALCL previously reported at Japanese academic conferences (Japan Oncoplastic Breast Surgery Society. http://jopbs.umin.jp/medical/index.html), of which only the first case has been published. Unlike the first case, this patient had clinical features that were highly suggestive of the postoperative chest wall recurrence of breast cancer, with a mass and rash on the skin. Case presentation: The patient was a 45-year-old woman who had undergone breast reconstruction after breast cancer surgery of the right breast 8 years previously. The patient presented with a mass and skin rash inside the inframammary area, and we suspected a damaged silicone breast implant (SBI) or chest wall recurrence. We examined the mass by a core needle biopsy and made a pathological diagnosis of BIA-ALCL. Imaging findings suggested internal thoracic lymph node swelling and lymphoma infiltration beyond the capsule but no metastatic lesions (cStage III). After en bloc resection of the SBI and lymphoma, adjuvant systemic therapy was performed. Conclusion: We encountered the third case of BIA-ALCL in Japan. This was a case with clinically advanced stage of disease; however, the BIA-ALCL was found to be in remission.