EUREKA Study:Phase 2 Study to Optimize Neoadjuvant Therapy in HER2-positive Early-stage Breast Cancer

EUREKA is a phase II study that will evaluate optimization of neoadjuvant therapy in patients with stage II-III HER2-positive breast cancer. This adaptive clinical trial will enroll patients with cT2-T3 N0-2 HER2-positive breast cancer. Tumors will undergo testing using HARPS assay to identify HARPS-positive and HARPS negative HER2-positive breast cancers. Patients with HARPS-positive HER2-positive breast cancer will be treated using an adaptive trial design to optimize neoadjuvant therapy such we are maximizing treatment efficacy while reducing risk of treatment related toxicities. Patient will be treated with dual HER2-targeted therapy (trastuzumab and pertuzumab) for 3 cycles. Treatment response will be monitored by ctDNA and MRI breast. If there is treatment response, patients will be treated with 6 cycles of trastuzumab and pertuzumab. If there is no treatment response after 6 weeks, then patients will be treated with the addition of single agent chemotherapy (docetaxel/paclitaxel/Abraxane) with trastuzumab/pertuzumab for 4 cycles followed by 2 cycles of trastuzumab and pertuzumab. Then patients will proceed with breast surgery. Patients with HARPS-negative HER2-positive breast cancer and detectable ctDNA at time of diagnosis will be treated with 4 cycles of Taxane, platinum, trastuzumab and pertuzumab, and they will be monitored with ctDNA for ctDNA clearance. Patients who have ctDNA clearance will be treated with additional 2 cycles of the same regimen and then proceed to have surgery. If patients have detectable ctDNA at 12 weeks, then neoadjuvant therapy will be escalated to add anthracycline based regimen or trastuzumab deruxtecan (T-DXD) pe treating physicians choice. The study will enroll a total of 50 patients- 25 patients with HARPS-positive HER2-positive early-stage breast cancer and 25 patients with HARPS-negative HARPS-positive early-stage breast cancer.