286TiPPhase II randomized trial of neoadjuvant trastuzumab and pertuzumab (TP) with either palbociclib + letrozole (Pal+L) or paclitaxel (Pac) for elderly patients with estrogen receptor & amp; HER2 positive (ER+/HER2+) breast cancer (BC) (International Breast Cancer Study Group IBCSG 55-17, TOUCH)

AbstractBackgroundHER2 blockade in combination with chemotherapy (CT) remains the treatment of choice for patients with early HER2+ BC, irrespective of ER status. Patients with HER2+ early BC co-expressing ER may benefit from HER2 blockade in combination with endocrine therapy (ET) and new targeted agents. Elderly patients benefit from HER2 blockade as much as younger ones but they have higher risks of adverse events, mostly induced by the CT partner, making de-escalation of CT appealing. Recent data have elucidated cyclin-dependent kinases 4 and 6 (CDK4/6) as key therapeutic targets functioning downstream of both ER and HER2 pathways suggesting CDK4/6 inhibitors like Pal may be ideal partners for ET in this context. Pre-clinical and clinical data suggest that a gene signature of functional loss of Retinoblastoma (RBsig) might predict sensitivity to CT vs CDK4/6i in ER+/HER2+ early BC. The TOUCH hypothesis is that neoadjuvant therapy with Pal + ET + dual HER2 blockade may be more active in patients with ER+/HER2+ RBsig LOW early BC while those with RBsig HIGH may require CT.Trial designTOUCH is an open-label, multicenter, randomized phase 2 neoadjuvant trial. 144 patients ≥65 years with ER+/HER2+ primary BC will be randomized (1:1) to dual HER2 blockade (5 doses T+P) + either Pal (125 mg/d po; 21 of 28d x 4 cycles) + L (daily x 16 weeks), or Pac (80 mg/m2 iv, d1,8,15 q28 days x 4 cycles), before surgery. RBsig (HIGH vs LOW) will be determined centrally on manda tory pre...
Source: Annals of Oncology - Category: Cancer & Oncology Source Type: research