Enhertu questions and experiences

Hello,

My original diagnosis in June 2022 was Stage IB (T2N1mi)

ER-93%
PR-70%
HER2 - (2+ by IHC 1.0 by FISH )
Ki-67-80%
I did lumpectomy and breast reduction, 4 rounds of TC, and anastrozole switched to fulvestrant due to side effects.

In April of 2025, my CA27-29 spiked and imaging was ordered. Signaterra negative for ctDNA (thought I was in the clear). Recurrence in lung was confirmed metastatic late May. ER- 55%, PR-3%, HER2- (1+ by IHC, 1.2 by FISH). Ki-67 not done. Not enough tumor for NGS. Started ribociclib June 19 (almost 60 days post tumor marker spike). Additional blood biopsy at MDA still negative for ctDNA. Completely asymptomatic. Tumor markers kept rising. Thoracoscopy 8/20 confirmed lung and pleura progression. ER-60%, PR negative, HER2 ? (2+ by IHC, FISH pending) Ki-67-90%

Headed for chemo to stop things growing. Was going to go nuclear option and do AC-T to wipe things out and then do fulvestrant and Verzenio to keep things at bay. After meeting with 2 med oncs and talking to a cancer biologist, I think I’m headed for Enhertu instead as it seems to have higher efficacy. My question is how many rounds or do you just take it indefinitely until progression? Has anyone on here had a complete pathological response with Enhertu? What are side effects like? Has anyone here been on Enhertu for > 12 months? I am interested in any/everyone’s experience…