Day 5 — Tuesday, June 2 (closing oral sessions)¶
The meeting's final day belonged to breast cancer, where a trio of HR+/HER2- and triple-negative readouts hit the oral stage in close succession — one practice-changing win, one elegant proof-of-concept for ctDNA-guided therapy, and one high-profile miss that took some shine off the oral SERD class. Heme rounded out the afternoon with early but provocative engineered-cell and menin-inhibitor data.
Breast — the headline trio¶
The day's loudest signal came from ASCENT-04 / KEYNOTE-D19. In previously untreated PD-L1+ (CPS ≥10) metastatic TNBC, sacituzumab govitecan plus pembrolizumab beat chemo plus pembro on the primary PFS endpoint (median 11.2 vs 7.8 mo; HR 0.65, P<0.001), and the ASCO update added PFS2/subsequent-therapy data plus a subgroup analysis showing benefit held across Trop-2 quartiles (Q4 HR 0.57), tBRCA status, and HER2 IHC0 (HR 0.69). This positions the Trop-2 ADC–IO doublet as a new first-line standard for this group.
SERENA-6 delivered the most conceptually important result of the day: a ctDNA-guided early switch to camizestrant + CDK4/6i at emergent ESR1-mutation detection — before radiographic progression — sustained benefit through the next line of therapy. Final PFS2 carried HR 0.52 (95% CI 0.33–0.81; P=0.0038), reinforcing the primary PFS win (16.0 vs 9.2 mo, HR 0.44). It is the strongest validation yet that serial ctDNA can drive a pre-emptive treatment change.
The disappointment was persevERA. The phase III study (N=992) missed its primary endpoint: giredestrant + palbociclib produced only a numerical, non-significant PFS improvement over letrozole + palbociclib in 1L ER+/HER2- advanced disease. The oral SERD is clearly active, but a frontline first-line edge over an aromatase inhibitor backbone did not materialize at the bar that was set.
Heme — engineered cells and menin maintenance¶
Two early-phase talks drew attention. CONQUER reported a first-in-human dual-epitope nanobody anti-CD5 CAR-T in R/R T-ALL/PTCL (n=18): ORR 77.8% and CR/CMR 61.1% overall, climbing to 100% ORR and 85.7% CR/CMR at the recommended phase 2 dose, with CRS in 66.7% of patients and no grade ≥3 events — a notable safety profile for T-cell-targeted CAR-T, where fratricide has long been the obstacle.
Revumenib post-HSCT maintenance (abstract 6505) presented the menin inhibitor as post-transplant maintenance in 21 adults and children with KMT2Ar, NPM1m, or NUP98r acute leukemia, reporting favorable overall survival and relapse rate against a historical pre-revumenib cohort. Numbers are small and the comparator is historical, but it extends the menin-inhibitor story into a high-unmet-need maintenance setting.
Closing read¶
If the plenary days were defined by the pan-RAS and PD-1×VEGF first-in-class wins, the closing day was defined by refinement: how to sequence ADCs and IO in TNBC, how to act on molecular relapse before it shows on a scan, and where an active oral SERD does — and does not — clear the bar. The breast trio together captured the meeting's broader theme that biomarker-directed timing, not just better drugs, increasingly decides outcomes.
Sources: ASCO press release — ASCENT-04/KEYNOTE-D19; CancerNetwork — ASCENT-04 subgroup analysis; ASCO abstract — SERENA-6 final PFS2; AJMC — SERENA-6 molecular-guided switch; Targeted Oncology — persevERA misses primary PFS; Syndax — revumenib post-transplant oral presentation (ASCO 2026); CancerNetwork — top lymphoma abstracts at ASCO 2026.