When immunotherapy stops working in metastatic clear-cell kidney cancer, is there still a place for trying it again? A new global real-world evidence study published in ESMO Open suggests the answer may depend less on which drug you pick and more on when you give it.
In a cohort of 288 patients with metastatic clear-cell renal cell carcinoma (mccRCC) treated across 143 healthcare organizations, those who received a second immune-checkpoint inhibitor (ICI) regimen at least six months after stopping their prior ICI lived significantly longer than those rechallenged sooner, with a median overall survival of 34.9 months versus 19.4 months. The association held up after propensity score matching, pointing to timing itself, rather than patient selection, as the likely driver.
The analysis, led by Antonio Cigliola and colleagues, used the TriNetX global federated health research platform to draw together anonymized records from major international centers between 2016 and 2024.
RCC Epidemiology in 2026
Kidney cancer is one of the 10 most common cancers in both men and women in the United States, accounting for about 3% to 5% of all cancers. Renal cell carcinoma (RCC) is the most common type of kidney cancer, and clear-cell RCC is the dominant histologic subtype in metastatic disease.
According to the American Cancer Society’s most recent estimates for 2026, about 80,450 new cases of kidney cancer (50,770 in men and 29,680 in women) will be diagnosed in the United States, and approximately 15,160 people (10,200 men and 4,960 women) will die from the disease (American Cancer Society, Cancer Facts & Figures 2026). These figures include all types of kidney and renal pelvis cancers, of which renal cell carcinoma accounts for roughly 90% (Kidney Cancer Association).
Kidney cancer is largely a disease of older adults. The average age at diagnosis is 65, with most cases occurring between ages 55 and 74, and it is approximately twice as common in men as in women, with higher incidence among African American, American Indian, and Alaska Native populations (American Cancer Society).
Read more about Kidney Cancer: Symptoms ,Causes, Stages, Diagnosis and Treatment on OncoDaily.
Clinical Context for ICI Rechallenge
Over the past decade, ICIs — alone or combined with tyrosine kinase inhibitors (TKIs) — have become the backbone of first-line therapy in mccRCC. But once patients progress, clinicians face a difficult question: is there still a role for immunotherapy?
Two recent phase III trials tried to answer it. CONTACT-03 compared atezolizumab plus cabozantinib with cabozantinib alone, and TiNivo-2 compared tivozanib plus nivolumab with tivozanib alone. Both failed to demonstrate a clinical benefit for ICI rechallenge, and both were associated with increased toxicity compared with the control arms. Neither trial, however, stratified outcomes by the interval between ICI exposures, leaving open the question of whether timing influences the efficacy of rechallenge.
Study Design and Patient Population
From 6,737 patients with mccRCC, 2,773 had received ICIs, and 288 patients — representing 10.4% of the ICI-treated cohort and 4.3% of the overall mccRCC cohort — received at least two sequential ICI-based regimens between 2016 and 2024. Key baseline characteristics included:
- Median age at diagnosis: 63.8 years (range 30–90)
- Female: 30%
- Stage IV at diagnosis: 37%
- Most common metastatic sites: lymph nodes (64%), lung (46%), liver (38%), bone (24%), brain (11%)
- Sarcomatoid features: 4.9%
The most common first-line regimens were nivolumab plus cabozantinib (44.1%), nivolumab plus ipilimumab (26.5%), pembrolizumab plus axitinib (20.0%), and pembrolizumab plus lenvatinib (8.4%).
The four most frequent rechallenge sequences were nivolumab → nivolumab (47.6%), pembrolizumab → pembrolizumab (22.2%), nivolumab → pembrolizumab (17.0%), and pembrolizumab → nivolumab (13.2%). Roughly one-third of patients (37%) moved directly from one ICI to the next, while 63% had at least one intervening systemic therapy in between.
Survival Outcomes: A Median OS of 33 Months After Rechallenge
After a median follow-up of 19.3 months, median overall survival following ICI rechallenge was 33.2 months, and median progression-free survival was 8.5 months. PFS was broadly similar across the main rechallenge sequences: 8.0 months for nivolumab followed by nivolumab, 7.0 months for nivolumab followed by pembrolizumab, 7.4 months for pembrolizumab followed by pembrolizumab, and 9.2 months for pembrolizumab followed by nivolumab.
PFS was also similar between patients previously treated with nivolumab plus ipilimumab and those treated with ICI–TKI combinations, suggesting that switching between PD-1 inhibitors did not clearly improve outcomes compared with rechallenge using the same agent.
You can also read about Kidney Cancer Cure Rate and Survival Outcome on OncoDaily.
Key Finding: The 6-Month Interval
The most clinically relevant signal came from the interval between ICI exposures. Patients rechallenged at least six months after prior ICI therapy had longer median PFS than those rechallenged within six months, at 8.8 versus 5.2 months. Median OS was also longer in the ≥6-month group, at 34.9 versus 19.4 months, with a statistically significant difference (P = 0.014).
After propensity score matching for age, sex, stage, metastatic sites, prior ICI type, and sequencing strategy, the OS association remained significant (P = 0.03). A 12-month threshold also favored later rechallenge numerically (34.9 versus 25.9 months), although that difference did not reach statistical significance, possibly reflecting limited power or unmeasured confounding.
Why Timing May Matter Biologically
Biologically, a longer interval between ICI exposures may allow partial recovery of immune function after sustained PD-1/PD-L1 blockade, including reduced immune exhaustion, restoration of antigen presentation, and recruitment of new immune clones. Intervening TKI-based therapy may also contribute to changes in the tumor immune microenvironment.
Together, these mechanisms could help restore sensitivity to checkpoint blockade in selected patients and support the hypothesis that timing may be more important than the specific ICI sequence.
Sarcomatoid Subgroup: No Clear Extra Benefit
Despite the typically higher immunogenicity of sarcomatoid tumors, the small sarcomatoid subgroup (n = 14) did not appear to derive enhanced benefit from rechallenge, with a median OS of 35.1 months and PFS of 6.6 months, broadly in line with the overall cohort. Because this subgroup was small, these findings should be interpreted cautiously, but they suggest that sarcomatoid features alone did not clearly identify patients with enhanced benefit from ICI rechallenge.
Limitations
The study has several limitations inherent to retrospective real-world analyses, including lack of randomization, potential selection bias, heterogeneity in clinical practice and surveillance across institutions, reliance on ICD-10 coding without centralized pathology or radiology review, and missing data on response depth, symptomatic benefit, and toxicity.
What This Means for the Clinic and for Future Trials
After the negative CONTACT-03 and TiNivo-2 results, enthusiasm for ICI rechallenge in mccRCC has been understandably limited. This real-world analysis complicates that picture, suggesting that timing may influence whether selected patients benefit from rechallenge, particularly when no better alternatives or suitable clinical trials are available.
For clinical practice, the interval between ICI exposures, and particularly the 6-month threshold, may help inform discussions about rechallenge in patients with limited remaining options. For trial design, the findings argue for prospective studies that stratify patients by inter-treatment interval and evaluate whether this interval could serve as a surrogate marker of likely response.
ICI rechallenge in mccRCC should not be categorically dismissed. It should be evaluated more carefully in prospective studies, with particular attention to the timing between immunotherapy exposures.
The full article is available in ESMO Open.