Clinical and Molecular Validation of the Very Favorable IMDC Risk Group in Metastatic Renal Cell Carcinoma.

The International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk criteria stratify metastatic renal cell carcinoma (mRCC) into favorable, intermediate, and poor risk groups, but heterogeneity within the favorable risk category remains poorly understood.

To evaluate a proposed very favorable subgroup (tier 1: Karnofsky Performance Status ≥90%; diagnosis to treatment ≥3 years; and no brain, liver, and bone metastases) and characterize its molecular and clinical features.

This retrospective cohort study analyzed IMDC data, from January 2015 to September 2024, of patients with favorable risk mRCC (tier 1 and tier 2 [favorable and not tier 1]). Molecular profiling leveraged IMmotion151 (A Study of Atezolizumab in Combination With Bevacizumab Versus Sunitinib in Participants With Untreated Advanced Renal Cell Carcinoma) trial data with whole-exome sequencing, RNA sequencing, and programmed cell death ligand 1 immunohistochemistry.

Systemic standard of care treatments for mRCC, which include vascular endothelial growth factor receptor targeted therapy (VEGF-TT [sunitinib or pazopanib]), immune-oncology-VEGF (IO-VE [pembrolizumab and axitinib, pembrolizumab and lenvatinib, nivolumab and cabozantinib, or avelumab and axitinib]), and 2 IO (IO-IO [ipilimumab and nivolumab]) regimens.

The primary end point of this study was overall survival (OS) at 2 years of the favorable risk group and in the tier 1 and tier 2 subgroups with the different treatment options. Secondary end points included time to next treatment, treatment duration, and overall response rate. Outcomes were compared across treatment types: VEGF-TT, IO-VE, and IO-IO.

Among 641 patients with favorable risk mRCC (median [IQR] age, 65 [58-71] years; 475 males [74.1%]), 176 (27.5%) were in tier 1, and 465 (72.5%) were in tier 2. Those in tier 1 met criteria for a very favorable subgroup, characterized by similar age and treatment distribution but lower rates of sarcomatoid features; more patients with only 1 metastatic site; and an absence of brain, bone, and liver metastases compared with patients in tier 2 with favorable risk. Patients in tier 1 showed a median OS of 79.1 (95% CI, 73.7 to not reached) months vs 54.5 (95% CI 45.5-67.7) months in tier 2 (P < .001) and distinct molecular features: high polybromo-1 alterations (64.7%), low BRCA1-associated protein 1 alterations (8.8%), and programmed cell death ligand 1 positivity (21.9%); transcriptomics revealed less immune-infiltrated tumors (8.5% immunogenic clusters) than in the other subgroups. Clinically, IO-IO underperformed in tier 1, with a 2-year OS of 73.1% (95% CI, 49.1%-97.1%) vs 89.1% (95% CI, 79.0%-99.2%) with IO-VE and 92.4% (95% CI, 86.5%-98.3%) for VEGF-TT (IO-IO hazard ratio, 3.64 [95% CI, 1.49-9.06]; P = .005), and a lower overall response rate (26.3% vs 63.3% in IO-VE and 57.0% in VEGF-TT).

In this cohort study, the very favorable risk subgroup had a less immunogenic molecular profile and superior outcomes from VEGF-containing regimens (VEGF-TT and IO-VE) compared with the favorable risk group. The IO-IO combination showed significantly worse survival in this population, suggesting that VEGF inhibition remains essential for optimal outcomes.

JAMA network open. 2026 Apr 01*** epublish ***

Martin Zarba, Eddy Saad, Karl Semaan, Talal El Zarif, Evan Ferrier, Connor Wells, Razane El Hajj Chehade, Naveen S Basappa, Hedyeh Ebrahimi, Mahrukh Huseni, Romain Banchereau, Rana R McKay, Lori Wood, Benoit Beuselinck, Cristina Suárez, Kosuke Takemura, Aly-Khan A Lalani, Haoran Li, Lavinia Anne Spain, Arnoud J Templeton, Thomas B Powles, Georg A Bjarnason, Guillermo de Velasco, Toni K Choueiri, Daniel Y C Heng

Department of Medical Oncology, Arthur JE Child Comprehensive Cancer Centre, Calgary, Alberta, Canada., Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts., Yale University, New Haven, Connecticut., University of Calgary, Calgary, Alberta, Canada., Department of Medical Oncology, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada., Department of Medical Oncology, City of Hope Comprehensive Cancer Center, Duarte, California., Genentech, San Francisco, California., Department of Medical Oncology, University of California San Diego Health, La Jolla., Division of Medical Oncology, Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada., Department of Medical Oncology, Universitair Ziekenhuis Leuven, Leuven, Belgium., Medical Oncology, Vall d'Hebron Institute of Oncology, Vall d'Hebron University Hospital, Barcelona, Spain., Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan., Department of Medical Oncology, McMaster University, Hamilton, Ontario, Canada., Department of Medical Oncology, Huntsman Cancer Institute, University of Utah, Salt Lake City., Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia., Department of Medical Oncology, St Claraspital, Basel, Switzerland., Department of Medical Oncology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom., Department of Medical Oncology, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada., Medical Oncology Department, Hospital Universitario 12 de Octubre, Madrid, Spain.