PET Dynamics to Response-Adapted Neoadjuvant Therapy in TNBC

Overview

Eligible patients with stage 2 and 3 triple negative breast cancer will be treated with 4 cycles of neoadjuvant paclitaxel/carboplatin/pembrolizumab. A PET scan will be performed at baseline and after 1 cycle of therapy. A breast MRI will be performed after treatment completion. Patients with complete clinical response will proceed to surgery. Patients with clinical residual disease will complete neoadjuvant rescue with 4 cycles of doxorubicin/cyclophosphamide prior to surgery. If residual disease identified after surgery, adjuvant therapy to be determined by the treating oncologist (may include doxorubicin/cyclophosphamide/pembrolizumab, capecitabine etc).

Eligible participants will undergo baseline procedures including research bloodwork, MRI and PET scan. Participants will then be treated with one cycle of paclitaxel, carboplatin and pembrolizumab (TCarbo/pembro). At the end of Cycle one patients will undergo repeat procedures (bloodwork and PET scan), and then continue with treatment for an additional three cycles. ctDNA will be collected on day 1 of each cycle. At the end of treatment patients will undergo repeat MRI. Patients achieving a clinical complete response (CR) on MRI will proceed with surgery. Patients with clinical residual disease (RD) on MRI will be recommended a biopsy, and be recommended "rescue" neoadjuvant doxorubicin and cyclophosphamide with pembrolizumab (AC/pembro) for four additional cycles, and then proceed with surgery. Note: patients/treating physician may opt to proceed with surgery. Archival tissue will be collected from the surgical product. Patients achieving a pathologic CR (pCR) may proceed with adjuvant pembrolizumab per standard of care, and treating physician's discretion. Patients with pathological RD may proceed with "rescue" adjuvant AC/pembrolizumab for four additional cycles (if not given neoadjuvantly), per treating physician discretion. The participants may also receive Aadjuvant capecitabine or olaparib as indicated and per treating physician's discretion.