Peter Schmid

The latest in a line of negative targeted-therapy trials in triple-negative disease (EGFR, VEGF, iniparib, now AKT): a modest delay in progression that did not translate into survival, in the same year that an antibody-drug conjugate did. It is why the roadmap treats pathway-targeted small molecules as the road not taken.

The first-line overall survival result that made an antibody-drug conjugate the standard for PD-L1-negative or immunotherapy-ineligible metastatic triple-negative disease, and the reason the sequencing question (which TROP2 drug first, what after it) is now urgent.

For stage II-III triple-negative breast cancer, chemotherapy plus pembrolizumab before surgery and pembrolizumab alone afterwards is now the standard approach worldwide, and the survival gain is real, not just a surrogate. It does not apply to stage I disease or to hormone-receptor-positive or HER2-positive cancers. The price is a year of immunotherapy with a meaningful chance of a permanent endocrine side effect such as hypothyroidism or adrenal insufficiency.

The clearest demonstration that PD-L1 positive in triple-negative breast cancer means different things depending on the kit; with atezolizumab withdrawn, pembrolizumab's 22C3 combined positive score of 10 is the surviving standard, and roughly a quarter of patients get a different answer depending on which assay their laboratory runs.

PAKT gives the trial-based prevalence of PI3K-pathway alteration in first-line metastatic TNBC (one in five) and the strongest signal for AKT inhibition in that subgroup; the phase 3 CAPItello-290 did not confirm it.

Enzalutamide works modestly in AR-positive TNBC and is the reference for the LAR subtype's therapy implication; the AR threshold used for eligibility changes who counts as positive.