Trastuzumab deruxtecan versus trastuzumab emtansine in Asian patients with HER2-positive metastatic breast cancer.

The global phase 3 DESTINY-Breast03 study (ClinicalTrials.gov; NCT03529110) showed statistically significant and clinically meaningful improvements in progression-free survival (PFS) and overall survival (OS) with trastuzumab deruxtecan (T-DXd) over trastuzumab emtansine (T-DM1) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) previously treated with trastuzumab and a taxane. Here, we report a subgroup analysis of Asian patients enrolled in DESTINY-Breast03. In total, 309 patients (149 in the T-DXd arm and 160 in the T-DM1 arm) from Asian countries and regions were randomized. At data cutoff (July 25, 2022), the median duration of follow-up in the Asian subpopulation was 29.0 months with T-DXd and 26.0 months with T-DM1. The PFS (determined by blinded independent central review) hazard ratio was 0.30 (95% confidence interval 0.22-0.41) favoring T-DXd over T-DM1 (median PFS 25.1 vs. 5.4 months). Median OS was not reached in the T-DXd arm and was 37.7 months in the T-DM1 arm. The median treatment duration was 15.4 months with T-DXd and 5.5 months with T-DM1. The incidence of grade ≥3 drug-related treatment-emergent adverse events was similar between both treatment arms (49.0% vs. 46.5%) and was consistent with the overall DESTINY-Breast03 population. Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 12.9% of patients treated with T-DXd and 2.5% treated with T-DM1, with a higher incidence in Japanese patients; none of these were grade ≥4 events. These efficacy and safety data reinforce the favorable benefit-risk profile of T-DXd in HER2-positive mBC, including in the Asian subgroup.

SGLT2 inhibition improves PI3Kα inhibitor-induced hyperglycemia: findings from preclinical animal models and from patients in the BYLieve and SOLAR-1 trials.

PURPOSE: Alpelisib plus fulvestrant demonstrated a significant progression-free survival benefit versus fulvestrant in patients with PIK3CA-mutated HR+ /HER2- advanced breast cancer (ABC) (SOLAR-1). Hyperglycemia, an on-target adverse effect of PI3Kα inhibition, can lead to dose modifications, potentially impacting alpelisib efficacy. We report data from preclinical models and two clinical trials (SOLAR-1 and BYLieve) on Sodium glucose cotransporter 2 inhibitor (SGLT2i) use to improve PI3Kα inhibitor-associated hyperglycemia. METHODS: Healthy Brown Norway (BN), mild diabetic Zucker diabetic fatty (ZDF), and Rat1-myr-p110α/HBRX3077 tumor-bearing nude rats treated with alpelisib were analyzed for glucose and insulin control with metformin and dapagliflozin (SGLT2i) and alpelisib efficacy. Hyperglycemia adverse events (AEs) were compared between patients receiving SGLT2i with alpelisib (n = 19) and a propensity score-matched cohort not receiving SGLT2i (n = 74) in both trials. RESULTS: Dapagliflozin and metformin in BN and ZDF rats treated with alpelisib normalized blood glucose and reduced insulin levels. No signs of ketosis or drug-drug interaction were observed when metformin and dapagliflozin was administered with alpelisib. Alpelisib antitumor efficacy was maintained when used with dapagliflozin in tumor-bearing rats. Compared with a matched set of patients without SGLT2i, patients receiving SGLT2i had 4.9 and 6.4 times lower rates of grade ≥ 3 hyperglycemia AEs and hyperglycemia AEs resulting in alpelisib dose adjustments, interruptions, or withdrawals, respectively, and a relative reduction in risk of experiencing these AEs (70.6% and 35.7%). CONCLUSION: These data suggest adding an SGLT2i can effectively manage hyperglycemia, resulting in fewer alpelisib dose modifications and discontinuations in patients with PIK3CA-mutated HR+ /HER2- ABC (SOLAR-1: NCT02437318; BYLieve: NCT03056755).

Real-world data on patients with early breast cancer who were prescribed abemaciclib adjuvant therapy in Japan.

Aim: To understand the real-world use of abemaciclib in Japanese patients with early breast cancer (EBC). Methods: This retrospective observational study was conducted using a Japanese administrative claims database in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative EBC who received abemaciclib adjuvant therapy from December 2021-March 2023. Patient characteristics and treatment patterns were summarized. Results: Among 374 patients, 38.2, 51.6 and 63.4% patients received neoadjuvant chemotherapy, adjuvant chemotherapy and radiotherapy, respectively; 13.1% were chemotherapy naive. Tamoxifen (37.7%), letrozole (35.6%), anastrozole (24.3%) were the commonly prescribed concomitant adjuvant endocrine therapies. Abemaciclib dose reductions were observed in 42.0% patients. Conclusion: Use of abemaciclib for treatment of high-risk EBC was described, which could help inform patient selection and treatment patterns.

Abemaciclib (150 mg twice daily) is prescribed with hormonal therapy for the treatment of early breast cancer (EBC) with high risk of recurrence. We used a big database from Japan that has anonymized information about 44 million patients from 480 hospitals. We aim to describe the characteristics of patients with EBC who receive abemaciclib and their treatment patterns in Japan.We included 374 patients with EBC who had breast cancer surgery and were prescribed abemaciclib with hormonal therapy between December 2021 and March 2023. The median age of patients is 54 years, almost all (99.2%) are female. The most commonly prescribed hormonal therapy with abemaciclib is tamoxifen (37.7%), letrozole (35.6%) and anastrozole (24.3%).Of the 374 patients who were prescribed abemaciclib, 38.2% patients received chemotherapy before surgery, 51.6% received chemotherapy after surgery and 63.4% received radiation therapy after surgery; whereas, 13.1% received no perioperative chemotherapy before abemaciclib therapy. Around 42% of patients reduced their dose from starting dose of abemaciclib. Higher proportion of older patients and patients with low body weight, had dose reduction. Majority of the patients are prescribed either an antidiarrheal agent or probiotic within a day of starting abemaciclib.This is the first study describing patient characteristics and treatment patterns of Japanese patients who are prescribed abemaciclib in the clinical practice. The results will help understand who can benefit from abemaciclib, and to choose the most appropriate patients to receive abemaciclib for the treatment of EBC.

Characterization of KIF20B as a novel prognostic biomarker and therapeutic target for breast cancer.

Despite advances in treatment and early detection, breast cancer remains one of the most common types of cancer and is the second leading cause of cancer death after lung cancer in women. Therefore, there is an urgent need to develop new biomarkers and therapeutic targets for the treatment of breast cancer. Based on gene expression profiles and subsequent screening performed in a preliminary study, kinesin family member 20B (KIF20B) was selected as a candidate target molecule, because it was highly and frequently expressed in all subtypes of breast cancer and barely detected in normal tissues. Reverse transcription­quantitative PCR and western blotting revealed that KIF20B mRNA and protein expression levels were upregulated in most breast cancer cell lines but were scarcely expressed in normal mammary epithelial cells. Immunohistochemical staining of a tissue microarray showed that KIF20B was detected in 145 out of 251 (57.8%) breast cancer tissues. Strong KIF20B expression was significantly related to advanced pathological N stage. Moreover, patients with breast cancer and strong KIF20B expression exhibited a significantly worse prognosis than those with weak or negative KIF20B expression (P<0.0001, log­rank test). In multivariate analysis, strong expression was an independent prognostic factor for patients with breast cancer. Furthermore, knockdown of KIF20B expression by small interfering RNA inhibited breast cancer cell proliferation and induced apoptosis. In addition, Matrigel cell invasion assays revealed that the invasiveness of breast cancer cells was significantly decreased by KIF20B silencing. Since KIF20B is an oncoprotein that is strongly expressed in highly malignant clinical breast cancer and serves a pivotal role in breast cancer cell proliferation, survival and invasion, KIF20B could be considered a candidate biomarker for prognostic prediction and a potential molecular target for developing new therapeutics, such as small molecule inhibitors, for a wide variety of breast cancers.

Trastuzumab deruxtecan versus treatment of physician's choice in previously treated Asian patients with HER2-low unresectable/metastatic breast cancer: subgroup analysis of the DESTINY-Breast04 study.

BACKGROUND: In the global phase 3 DESTINY-Breast04 study (NCT03734029), the anti-human epidermal growth factor 2 (HER2) antibody-drug conjugate trastuzumab deruxtecan (T-DXd) demonstrated a statistically significant improvement in progression-free survival (PFS) and overall survival (OS), with manageable safety compared with treatment of physician's choice (TPC) in patients with HER2-low metastatic breast cancer (mBC) who had received 1-2 prior lines of chemotherapy. METHODS: This subgroup analysis examined the efficacy and safety of T-DXd versus TPC in 213 patients from Asian countries and regions who were enrolled in the DESTINY-Breast04 trial and randomized to T-DXd (n = 147) or TPC (n = 66). RESULTS: Median PFS with T-DXd and TPC was 10.9 and 5.3 months, respectively, in Asian patients with hormone receptor-positive mBC, and 10.9 and 4.6 months, respectively, in the overall Asian population. In both populations, median OS was not reached with T-DXd and was 19.9 months with TPC. The objective response rate was higher with T-DXd versus TPC in all Asian patients. Median treatment duration was 8.4 months with T-DXd and 3.5 months with TPC. The most common grade ≥ 3 drug-related treatment-emergent adverse events in Asian patients treated with T-DXd were neutropenia (16.3%), anemia (12.9%), and leukopenia (11.6%); the incidences of neutropenia and leukopenia were higher with TPC versus T-DXd. Adjudicated drug-related interstitial lung disease or pneumonitis with T-DXd was 14.3%; the majority of events were grade 1-2. CONCLUSIONS: T-DXd demonstrated clinically meaningful survival benefits versus TPC in Asian HER2-low mBC patients, regardless of hormone receptor status, with no new safety signals. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, NCT03734029.

Inhibition of lysine acetyltransferase KAT6 in ER+HER2- metastatic breast cancer: a phase 1 trial.

Inhibition of histone lysine acetyltransferases (KATs) KAT6A and KAT6B has shown antitumor activity in estrogen receptor-positive (ER+) breast cancer preclinical models. PF-07248144 is a selective catalytic inhibitor of KAT6A and KAT6B. In the present study, we report the safety, pharmacokinetics (PK), pharmacodynamics, efficacy and biomarker results from the first-in-human, phase 1 dose escalation and dose expansion study (n = 107) of PF-07248144 monotherapy and fulvestrant combination in heavily pretreated ER+ human epidermal growth factor receptor-negative (HER2-) metastatic breast cancer (mBC). The primary objectives of assessing the safety and tolerability and determining the recommended dose for expansion of PF-07248144, as monotherapy and in combination with fulvestrant, were met. Secondary endpoints included characterization of PK and evaluation of antitumor activity, including objective response rate (ORR) and progression-free survival (PFS). Common treatment-related adverse events (any grade; grades 3-4) included dysgeusia (83.2%, 0%), neutropenia (59.8%, 35.5%) and anemia (48.6%, 13.1%). Exposure was approximately dose proportional. Antitumor activity was observed as monotherapy. For the PF-07248144-fulvestrant combination (n = 43), the ORR (95% confidence interval (CI)) was 30.2% (95% CI = 17.2-46.1%) and the median PFS was 10.7 (5.3-not evaluable) months. PF-07248144 demonstrated a tolerable safety profile and durable antitumor activity in heavily pretreated ER+HER2- mBC. These findings establish KAT6A and KAT6B as druggable cancer targets, provide clinical proof of concept and reveal a potential avenue to treat mBC. clinicaltrial.gov registration: NCT04606446 .

TP53 signature predicts pathological complete response after neoadjuvant chemotherapy for breast cancer: Observational and confirmational study using prospective study cohorts.

The TP53 signature is considered a predictor of neoadjuvant chemotherapy (NAC) response and prognostic factor in breast cancer. The objective of this study was to confirm TP53 signature can predict pathological complete response (pCR) and prognosis in cohorts of breast cancer patients who received NAC in prospective studies. Development cohorts (retrospective [n = 37] and prospective [n = 216] cohorts) and validation cohorts (NAC administered prospective study cohorts [n = 407] and retrospective perioperative chemotherapy (PC)-naïve, hormone receptor (HrR)-positive cohort [PC-naïve_HrR+ cohort] [n = 322]) were used. TP53 signature diagnosis kit was developed using the development cohorts. TP53 signature predictability for pCR and the relationship between recurrence-free survival (RFS), overall survival (OS), and the TP53 signature were analyzed. The pCR rate of the mutant (mt) signature group was significantly higher than that of the wild-type (wt) signature group (odds ratio, 5.599; 95 % confidence interval = 1.876-16.705; P = 0.0008). The comparison of the RFS and OS between the HrR+ and HER2- subgroup of the NAC cohort and of the PC-naïve_HrR+ cohort indicated that the RFS and OS benefit of NAC was greater in the mt signature group than in the wt signature group. From post hoc analyses, the RFS and OS benefit from adding capecitabine to FEC+T as NAC might be observed only in the mt signature group. The TP53 signature can predict the pCR after NAC, and the RFS and OS benefit from NAC may be greater in the mt signature group than in the wt signature group.