ESMO 2026 cancer data split practice-changing wins from early signals

As the European Society for Medical Oncology (ESMO) 2026 Congress opens in Madrid on 23 October, preview and pre-congress releases show two kinds of readouts: late-stage or registrational programs that may change practice, and early signals that need confirmation.

Pre-congress previews set the agenda

On 12 October, CURE previewed five late-breakers: INTerpath-001, SAFFRON, HARMONi-GI1, CLARITY-Gastric01, and TroFuse-005. All had topline claims: intismeran autogene plus pembrolizumab improved recurrence-free and distant metastasis-free survival in resected stage 2B-4 melanoma; savolitinib plus osimertinib beat chemotherapy on progression-free and overall survival in MET-altered EGFR-mutant NSCLC after Tagrisso failure; ivonescimab met overall survival in biliary tract cancer; sonesitatug vedotin met overall survival in pretreated gastric, gastroesophageal junction or esophageal cancer; and sacituzumab tirumotecan met overall survival and progression-free survival in endometrial cancer after platinum and immunotherapy. INTerpath-001 is due 24 October; SAFFRON, HARMONi-GI1 and CLARITY-Gastric01 on 25 October; and TroFuse-005 on 26 October. CURE cautioned that none of these treatments was approved and the size of benefit was still unknown.

OncLive also highlighted breast cancer abstracts: NATALEE 6-year overall survival, PANKU-Breast01, lidERA patient-reported outcomes, atirmociclib phase 2, and exploratory brain-metastasis analyses from TROPION-Breast02 and DESTINY-Breast09. MD Anderson Cancerwise outlined five investigator-led studies: olomorasib plus chemo-immunotherapy in KRAS G12C-mutant NSCLC, IGNITE-TX cascade genetic testing, Nous-209 revaccination in Lynch syndrome, ctDNA monitoring in early triple-negative breast cancer, and a folate receptor alpha ADC in platinum-resistant ovarian cancer. Oncology News Central reported that dostarlimab had received FDA approval days before ESMO for dMMR/MSI-H locally advanced rectal cancer, based on AZUR-1 interim results showing nearly three-fourths of patients were free from surgery, radiation or chemotherapy for at least 1 year. On 22 October, Cancer Therapy Advisor added PROTEUS, OptimUM, UV1, CheckMate 8HW final overall survival, KEYNOTE-564 final, and the Krascendo 1 head-to-head of divarasib versus sotorasib or adagrasib in KRAS G12C-mutant NSCLC. The same day, NEC reported 5 pathological complete responses among 8 patients in a phase I/II oral neoantigen therapy trial.

Which results are likely to change practice

The strongest candidates are phase 3 or registrational programs with efficacy data from previews and, in one case, regulatory approval already in hand. AZUR-1 is the clearest: the FDA approved dostarlimab monotherapy for dMMR/MSI-H locally advanced rectal cancer days before ESMO, with a median follow-up of more than 2 years and nearly three-quarters of patients avoiding surgery, chemotherapy and radiation for at least a year. INTerpath-001 is a phase 3 adjuvant melanoma study that met both recurrence-free and distant metastasis-free survival, and updated data are scheduled for Presidential Symposium I. SAFFRON is a global phase 3 that met progression-free and overall survival in MET-altered NSCLC after osimertinib, offering an oral-only option in a post-Tagrisso population. TroFuse-005 is a 776-patient phase 3 that met overall survival and progression-free survival, and CURE reported that sacituzumab tirumotecan is the first ADC to improve both in a global phase 3 trial in this setting. CheckMate 8HW and KEYNOTE-564 final analyses could consolidate established indications.

Krascendo 1, listed as divarasib versus sotorasib or adagrasib in previously treated KRAS G12C-mutant NSCLC, could influence second-line KRAS treatment if divarasib proves superior, but the preview does not report the trial phase or the size of any benefit.

Which results remain early or limited

Several readouts are not practice-changing now because they come from small or pilot cohorts, pre-interim analyses, or single-country trials. NECVAX-NEO1 reported 5 pathological complete responses among 8 TNBC patients in a phase I/II neoadjuvant study; the company said it is expanding to 28 patients and has US IND approval, but no comparative efficacy is yet available. IGNITE-TX is a pilot feasibility study of cascade genetic testing, not a cancer outcome trial, though it raised testing rates from 3.4% with usual care to 76.1% with intervention plus no-cost counseling. The Nous-209 revaccination data are from an expansion cohort, and the FRα ADC is a phase 1/2a signal; both need larger trial confirmation. B-STRONGER-I is a pre-interim analysis showing 96% baseline ctDNA detection and 82% clearance, but follow-up studies are still being designed. HARMONi-GI1 met overall survival but enrolled 682 patients in China; CURE said experts will watch the size of the benefit and confirmation in other countries may be needed. Exploratory brain-metastasis analyses from TROPION-Breast02 and DESTINY-Breast09 are secondary and cannot yet guide practice.