Ecaterina E. Dumbrava

Advances in Targeting HER2 across Cancer Subtypes: A Pan-Tumor Approach

Abstract Human epidermal growth factor receptor 2 (HER2) is an established therapeutic target in multiple solid tumors, particularly breast and gastric cancers. Significant advancements have been made in the development of HER2-targeted therapies, including monoclonal antibodies, tyrosine kinase inhibitors, antibody–drug conjugates (ADC), and novel bispecific antibodies. These agents have revolutionized the treatment landscape for HER2-positive metastatic cancers, resulting in improved progression-free and overall survival, and quality of life for patients. Beyond breast and gastric cancers, HER2 expression/amplification has been observed in other solid tumors, such as colorectal, lung, bladder, ovarian, and biliary tract cancers, offering new opportunities for personalized therapy in a larger patient population. In this review, we highlight the current state of HER2-targeted treatment strategies across HER2-expressing solid tumors, discussing the clinical efficacy, adverse event profiles, and challenges of existing therapies. We explore emerging treatment approaches, including novel agents such as HER2-targeting ADCs, combination therapies, and strategies to overcome resistance mechanisms. Additionally, we examine the role of HER2 expression heterogeneity, biomarker-driven patient selection, and diagnostic tools for patient selection and optimization of treatment outcomes. This review also investigates ongoing challenges in expanding HER2-targeted therapies, including addressing intrinsic and acquired resistance and tailoring strategies to low HER2-expressing or HER2-mutant tumors. Lastly, we provide insights into future directions, emphasizing the importance of precision oncology to broaden the therapeutic opportunities of HER2-targeted therapies across diverse HER2-driven malignancies.

Multicenter Phase II Trial of the WEE1 Inhibitor Adavosertib in Refractory Solid Tumors Harboring CCNE1 Amplification

PURPOSE Preclinical cancer models harboring CCNE1 amplification were more sensitive to adavosertib treatment, a WEE1 kinase inhibitor, than models without amplification. Thus, we conducted this phase II study to assess the antitumor activity of adavosertib in patients with CCNE1-amplified, advanced refractory solid tumors. PATIENTS AND METHODS Patients aged ≥ 18 years with measurable disease and refractory solid tumors harboring CCNE1 amplification, an Eastern Cooperative Oncology Group performance status of 0-1, and adequate organ function were studied. Patients received 300 mg of adavosertib once daily on days 1 through 5 and 8 through 12 of a 21-day cycle. The trial followed Bayesian optimal phase II design. The primary end point was objective response rate (ORR). RESULTS Thirty patients were enrolled. The median follow-up duration was 9.9 months. Eight patients had partial responses (PRs), and three had stable disease (SD) ≥ 6 months, with an ORR of 27% (95% CI, 12 to 46), a SD ≥ 6 months/PR rate of 37% (95% CI, 20 to 56), a median progression-free survival duration of 4.1 months (95% CI, 1.8 to 6.4), and a median overall survival duration of 9.9 months (95% CI, 4.8 to 15). Fourteen patients with epithelial ovarian cancer showed an ORR of 36% (95% CI, 13 to 65) and SD ≥ 6 months/PR of 57% (95% CI, 29 to 82), a median progression-free survival duration of 6.3 months (95% CI, 2.4 to 10.2), and a median overall survival duration of 14.9 months (95% CI, 8.9 to 20.9). Common treatment-related toxicities were GI, hematologic toxicities, and fatigue. CONCLUSION Adavosertib monotherapy demonstrates a manageable toxicity profile and promising clinical activity in refractory solid tumors harboring CCNE1 amplification, especially in epithelial ovarian cancer. Further study of adavosertib, alone or in combination with other therapeutic agents, in CCNE1-amplified epithelial ovarian cancer is warranted.