Real-world Assessment of Clinical Outcomes in Patients with Metastatic Renal Cell Carcinoma with or Without Sarcomatoid Features Treated with First-line Systemic Therapies

Background and objective Metastatic renal cell carcinoma (mRCC) patients have been reported to have better outcomes when treated with immunotherapies (IO) compared to targeted therapies (TT). This study aims to evaluate the impact of first-line systemic therapies on survival of mRCC patients with or without sarcomatoid features using real-world data. Methods Metastatic RCC patients of International mRCC Database Consortium (IMDC) intermediate or high risk, diagnosed from January 2011 to December 2022, treated with first-line systemic therapies, and with histological documentation of the presence or absence of sarcomatoid features in nephrectomy specimens were identified using the Canadian Kidney Cancer information system. Patients were classified by initial treatment: (1) targeted therapy (TT) used alone or (2) immunotherapy (IO)-based systemic therapies used in combination of either IO-IO or IO-TT. The inverse probability of treatment weighting using propensity scores was used to balance for covariates. Cox proportional hazard models were used to assess the impact of initial treatment received on overall survival (OS). Key findings and limitations Of the 1202 eligible patients, 791 were treated with TT and 411 with IO combinations. Of the patients, 76% were male, and the majority (91%) had a nephrectomy before systemic therapy. In nonsarcomatoid patients (639 TT and 320 IO patients), treatment with IO was associated with improved OS compared with patients treated with TT (median of 72 vs 48 mo, hazard ratio [HR] 0.63, 95% confidence interval [CI] 0.50–0.80, objective response rate [ORR] of 38.5% for IO and 23.5% for TT). In sarcomatoid patients (152 TT and 91 IO patients), treatment with IO was associated with improved OS (median of 48 vs 18 mo, HR 0.41, 95% CI 0.26–0.64, ORR of 49.5% for IO and 13.8% for TT). Similar results were observed in patients with synchronous metastatic disease only. Conclusions and clinical implications IO treatment was associated with improved survival in mRCC patients. The magnitude of benefit is increased in patients with sarcomatoid mRCC, consequently, identifying the sarcomatoid status early on could help healthcare providers make a better treatment decision. Patient summary Metastatic renal cell carcinoma (mRCC) patients of International mRCC Database Consortium intermediate and high risk, diagnosed from January 2011 to December 2022, treated with first-line systemic therapies, and with histological documentation of the presence or absence of sarcomatoid features in nephrectomy specimens were identified using the Canadian Kidney Cancer information system (CKCis). In this study, treatment with immunotherapy was associated to an improved survival and response rates for mRCC patients with and without sarcomatoid features. The magnitude of benefit is increased in patients with sarcomatoid mRCC.