Unveiling the Mechanism of Phenamacril Resistance in F. graminearum: Computational and Experimental Insights into the C423A Mutation in FgMyoI.

Phenamacril (PHA) is a highly selective fungicide for controlling fusarium head blight (FHB) mainly caused by F. graminearum and F. asiaticum. However, the C423A mutation in myosin I of F. graminearum (FgMyoI) leads to natural resistance to PHA. Here, based on the computational approaches and biochemical validation, we elucidate the atomic-level mechanism behind the natural resistance of F. graminearum to the fungicide PHA due to the C423A mutation in FgMyoI. The mutation leads to a rearrangement of pocket residues, resulting in increased size and flexibility of the binding pocket, which impairs the stable binding of PHA. MST experiments confirm that the mutant protein FgMyoIC423A exhibits significantly reduced affinity for PHA compared to wild-type FgMyoI and the nonresistant C423K mutant. This decreased binding affinity likely underlies the development of PHA resistance in F. graminearum. Conversely, the nonresistant C423K mutant retains sensitivity to PHA due to the introduction of a strong hydrogen bond donor, which facilitates stable binding of PHA in the pocket. These findings shed light on the molecular basis of PHA resistance and provide new directions for the creation of new myosin inhibitors.

Impact of HER2-targeted PET/CT imaging in patients with breast cancer and therapeutic response monitoring.

BACKGROUND: Patients with breast cancer exhibit heterogeneity in the expression of the human epithelial growth factor receptor 2 (HER2). Clinically, re-biopsying recurrent or metastatic lesions presents substantial challenges. This study aimed to evaluate the efficacy of HER2-targeted PET/CT imaging in identifying HER2 expression in breast cancer lesions and monitoring therapeutic responses. PATIENTS AND METHODS: This exploratory analysis used data from a prospective study that included adult patients with breast cancer who underwent both Al18F-NOTA-HER2-BCH and 18F-FDG PET/CT imaging at Beijing Cancer Hospital between June 2020 and July 2023 (NCT04547309). RESULTS: Fifty-nine participants, with a median age of 55 years, were analyzed. Lesions imaged with HER2-targeted PET/CT before anti-HER2 therapy exhibited higher SUVmax values than after therapy in HER2 immunohistochemistry (IHC) 3 + lesions (19.9, 95% CI: 15.7-25.3 vs 9.8, 95% CI: 5.6-14.7; P = .006). A significant positive correlation was observed between SUVmax on HER2-targeted PET/CT and IHC before therapy (P = .034), with higher SUVmax values noted in lesions with positive HER2 pathology compared to those with negative HER2 status (17.9 ±â€…13.2 vs 1.1 ±â€…0.3; P = .007). HER2 expression heterogeneity was confirmed both between primary and metastatic lesions (22.9%) and among different metastatic sites (26.7%) as assessed by HER2-targeted PET/CT. A superior therapeutic response correlated with higher pretreatment SUVmax values. The HER2-targeted PET/CT procedure was well-tolerated by all patients. CONCLUSION: HER2-targeted PET/CT imaging offers a practical, non-invasive, and quantitative approach for assessing HER2 status in breast cancer patients, facilitating the optimization and personalization of therapeutic strategies by oncologists.

Comparison of an Affibody-based Molecular Probe and 18F-FDG for Detecting HER2-Positive Breast Cancer at PET/CT.

Background Human epidermal growth factor receptor 2 (HER2) affibody-based tracers could be an alternative to nonspecific radiotracers for noninvasive detection of HER2 expression in breast cancer lesions at PET/CT. Purpose To compare an affibody-based tracer, Al18F-NOTA-HER2-BCH, and fluorine 18 (18F) fluorodeoxyglucose (FDG) for detecting HER2-positive breast cancer lesions on PET/CT images. Materials and Methods In this prospective study conducted from June 2020 to July 2023, participants with HER2-positive breast cancer underwent both Al18F-NOTA-HER2-BCH and 18F-FDG PET/CT. HER2 positivity was confirmed with pathologic assessment (immunohistochemistry test results of 3+, or 2+ followed by fluorescence in situ hybridization, indicated HER2 amplification). Two independent readers visually assessed the uptake of tracers on images. Lesion uptake was quantified using the maximum standardized uptake value (SUVmax) and target to background ratio (TBR) and compared using a general linear mixed model. Results A total of 42 participants (mean age, 56.3 years ± 10.1 [SD]; 41 female) with HER2-positive breast cancer were included; 42 (100%) had tumors that were detected with Al18F-NOTA-HER2-BCH PET/CT and 40 (95.2%) had tumors detected with 18F-FDG PET/CT. Primary tumors in two of 21 participants, lymph node metastases in four of 21 participants, bone metastases in four of 15 participants, and liver metastases in three of nine participants were visualized only with Al18F-NOTA-HER2-BCH. Lung metastasis in one of nine participants was visualized only with 18F-FDG. Al18F-NOTA-HER2-BCH enabled depiction of more suspected HER2-positive primary tumors (26 vs 21) and lymph node (170 vs 130), bone (92 vs 66), and liver (55 vs 27) metastases than 18F-FDG. The SUVmax and TBR values of primary tumors and lymph node, bone, and liver metastases were all higher on Al18F-NOTA-HER2-BCH images than on 18F-FDG images (median SUVmax range, 10.4-13.5 vs 3.4-6.2; P value range, <.001 to .02; median TBR range, 2.7-17.6 vs 1.2-7.8; P value range, <.001 to .001). No evidence of differences in the SUVmax and TBR for chest wall or lung metastases was observed between Al18F-NOTA-HER2-BCH and 18F-FDG (P value range, .06 to .53). Conclusion PET/CT with the affibody-based tracer Al18F-NOTA-HER2-BCH enabled detection of more primary lesions and lymph node, bone, and liver metastases than PET/CT using 18F-FDG. ClinicalTrials.gov Identifier: NCT04547309 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Ulaner in this issue.

Effectiveness of gonadotropin-releasing hormone agonists for ovarian function suppression in premenopausal patients with hormone receptor-positive breast cancer: a retrospective single-center real-world study.

PURPOSE: This study evaluated the effectiveness of ovarian function suppression (OFS) of various gonadotropin-releasing hormone agonists (GnRHa) combined with aromatase inhibitors (AI) in premenopausal patients with hormone receptor-positive (HR-positive) breast cancer. Potential risk factors associated with insufficient OFS were analyzed. PATIENTS AND METHODS: Premenopausal HR-positive breast cancer patients who had received AI with GnRHa were studied retrospectively. Patients were divided into different groups according to monthly or trimonthly GnRHa schedules they received, and the effectiveness of OFS was compared between groups. Insufficient OFS was defined as at least one instance of estradiol ≥ 30 pg/ml. Patient data was gathered from medical records for this comparison. RESULTS: Of the 264 patients enrolled in this study, 117 were administered 3.6 mg of goserelin monthly (goserelin 1 M group), 63 received 3.75 mg of leuprorelin monthly (leuprorelin 1 M group) and 84 were given 11.25 mg of leuprorelin every three months (leuprorelin 3 M group). Overall, 7.20% experienced insufficient OFS. The incidence rates in the three GnRHa depot groups were 7.69%, 6.35%, and 7.14%, respectively, without a significant statistical difference (P = 0.900). Notably, younger patients exhibited a higher likelihood of insufficient OFS [OR = 0.900, 95%CI (0.824-0.982), P = 0.018]. CONCLUSION: Insufficient OFS remains a concern during GnRHa and AI treatment. The effectiveness of the three GnRHa depots commonly used in China seems comparable. Younger patients face a heightened risk of insufficient OFS.

Abemaciclib plus endocrine therapy versus chemotherapy after progression on prior palbociclib in HR+/HER2- metastatic breast cancer: A single center real-world study in China.

BACKGROUND: Cyclin-dependent kinase (CDK) 4/6 inhibitor plus endocrine therapy (ET) become standard-of-care for patients with hormone receptor-positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) metastatic breast cancer (MBC). However, the optimal therapeutic paradigm after progression on CDK4/6 inhibitor remains unclear. This study aimed to evaluate the efficacy and safety of abemaciclib with switching ET versus chemotherapy after progression on prior palbociclib-based ET in Chinese patients with HR+/HER2- MBC. METHODS: From 414 consecutive patients with HR+/HER2- MBC who had been treated with palbociclib plus ET from September 2018 to May 2022 in Peking University Cancer Hospital, we identified 80 patients who received abemaciclib plus switching ET or chemotherapy after progression on palbociclib, matched for age, original stage at diagnosis, disease-free interval, and tumor burden at 1:1 ratio. The primary endpoint was progression-free survival (PFS) compared using the Kaplan-Meier method. A Cox proportional hazard model was performed to identify clinical factors associated with PFS in the abemaciclib group. RESULTS: The median PFS was 6.0 months (95% confidence interval [CI]: 3.94-8.06) in abemaciclib group and 4.0 months (95% CI, 2.52-5.49) in chemotherapy group (p = 0.667). And, there was no difference in median PFS between the sequential and nonsequential arm (6.0 vs. 6.0 months) in the abemaciclib group though fewer lines of prior systemic therapy and longer PFS from prior palbociclib in the sequential arm. However, patients with prior palbociclib as the first-line therapy had a significantly longer median PFS versus prior palbociclib as ≥2nd-line therapy (11.0 vs. 5.0 months, p = 0.043). Based on multivariable analysis, ER+/PR+ was an independent factor associated with longer PFS. There was no significant difference in overall survival between the abemaciclib and chemotherapy groups (p = 0.069). CONCLUSION: Our findings indicate that abemaciclib plus switching ET might be one of feasible treatment options for Chinese patients with HR+/HER2- MBC after progression on prior palbociclib-based therapy in addition to chemotherapy.

Real-world study of palbociclib combined with endocrine therapy for patients with metastatic breast cancer: A comparison of subsequent treatment patterns and HER2 expression analysis.

BACKGROUND: Cyclin-dependent kinase 4/6 inhibitors combined with endocrine therapy (ET) comprise the standard treatment for patients with hormone receptor-positive and human epidermal growth factor 2 (HER2)-negative metastatic breast cancer. The optimal systematic treatment after progression on palbociclib and the role of HER2 expression among these patients remain unclear. METHODS: The authors retrospectively identified 361 patients who received palbociclib combined with ET. Progression-free survival (PFS) and overall survival (OS) were analyzed based on subsequent treatments and HER2 status (PFSsub and OSsub, respectively). PFS1 and OS1 were calculated from palbociclib administration to disease progression/death and death from any cause, respectively. PFSsub and OSsub were calculated from subsequent treatment initiation. RESULTS: The median PFS1 and OS1 were 10.2 and 39.9 months, respectively. The median PFSsub and OSsub of 111 patients (54.7%) who received chemotherapy were 4.9 months and 20.0 months, respectively, whereas those of 89 patients (43.8%) who received endocrine backbone therapy were 5.9 months and 29.3 months, respectively. Among them, 31 patients (15.3%) who received abemaciclib combined with new ET showed better PFSsub and OSsub (12.2 months and not reached, respectively). The median PFS1 was significantly shorter in the HER2-low subgroup than in the HER2-zero subgroup among patients who received second-line or later palbociclib (6.1 vs. 7.8 months; p = .040) but did not differ among patients who received first-line palbociclib. CONCLUSIONS: Various regimens after palbociclib use were received. An improvement was noted in PFS among patients who received endocrine backbone therapy relative to chemotherapy, which may have been secondary to the receipt of chemotherapy by patients with more aggressive disease. HER2 status was not related to the effect of first-line palbociclib, but it may play a role in later lines.

Trastuzumab Biosimilar (HLX02), Pertuzumab Plus Chemotherapy in Patients with HER2-Positive Metastatic Breast Cancer after Progression of Trastuzumab: A Prospective, Phase II Study.

PURPOSE: This study aims to evaluate the efficacy and safety of trastuzumab biosimilar (HLX02) in combination with pertuzumab and chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) after progression of trastuzumab. MATERIALS AND METHODS: In this prospective, single-arm, phase II study, patients with HER2-positive MBC after progression of trastuzumab received pertuzuamb, HLX02, and chemotherapy in Beijing Cancer Hospital from March 2020 to December 2022. The primary endpoint was progression-free survival (PFS), and secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety. The study was registered with ClinicalTrials.gov (NCT05188495). RESULTS: A total of 45 patients were included in this study. Twelve patients (26.7%) were treated in second-line and 33 patients (73.3%) were in third-line and later setting. Eighty percent and 15.5% patients had previously received pyrotinib/lapatinib and T-DM1, respectively. With a median follow-up of 24.4 months (range, 1.2 to 43.9 months), the median PFS was 7.6 months (95% confidence interval, 4.3 to 10.9), OS was not reached, the ORR was 31.1%, and DCR was 91.1%. The treatment was well tolerated. CONCLUSION: The combination of trastuzumab biosimilar HLX02, pertuzumab, and chemotherapy exhibited promising efficacy and a favorable safety profile as second- and beyond-line treatment in HER2-positive MBC.

A round table discussion: clinical landscape of trastuzumab deruxtecan in breast cancer: a retrospective and prospective view.

The treatment landscape of breast cancer has been greatly changed by the innovative targeting therapies. Antibody-drug conjugates (ADCs) with a representative of trastuzumab deruxtecan (T-DXd) are the most successful ones. The revolutionary next-generation design of ADC transformed to the unprecedented clinical data. The DESTINY-BREAST01 and DESTINY-BREAST03 trials have changed the standard of care for HER2-positve metastatic breast cancer (MBC). At the same time the clinical data of T-DXd in HER2-postive patients with brain metastasis (BM) is numerously gaining and challenging the current treatment concept for central nerve system (CNS) involved disease. The DESTINY-BREAST series trials have quickly expanded to first-line (1L) and early setting of breast cancer. The newly reported positive result of DESTINY-BREAST04 trial has also opening the door of human epidermal growth factor receptor 2 (HER2)-low era. The breast cancer experts are facing a world of massive data and rapidly changing. Therefore, round table discussion meeting is a great way to share the information and options of among oncologists. This time, the breast cancer experts in China gathered to discuss the important clinical advances of T-DXd and its impact to clinical practice. The meeting minutes were recorded and organized as the review article. This would provide insights to better understanding of the current data and shape the further research directions of breast cancer.