Are immune checkpoint inhibitors a valid option for papillary renal cell carcinoma? A multicentre retrospective study

PD-L1 expression and its prognostic value in metastatic papillary renal cell carcinoma: Results from a GETUG multicenter retrospective cohort

INTRODUCTION

Papillary renal cell carcinoma (pRCC) is a rare and aggressive cancer with no specifically established therapeutic strategy in the metastatic setting. Combinations of tyrosine kinase and immune checkpoint inhibitors (ICI) are a promising option. We aimed to study the immune landscape of metastatic pRCC, and its interactions with angiogenesis pathways, to search for potential therapeutic targets.

METHODS

The expression of immune markers (PD-L1, PD-1, PD-L2, LAG-3) and angiogenic pathways (CAIX, c-MET), was analyzed by immunohistochemistry on 68 metastatic pRCC retrieved from a retrospective multicenter GETUG cohort. Our primary endpoint was to estimate the prevalence of PD-L1 expression and its prognostic impact in metastatic pRCC. Secondary endpoints included the evaluation of other immune markers (PD-1, PD-L2, and LAG-3) and their association with PD-L1. We also assessed angiogenic markers and their association with PD-L1.

RESULTS

Overall, 27.9 % of tumors were PD-L1 positive. PD-L2 was more frequently expressed (45.6 %), PD-1 and LAG-3 were positive in 17.6 % and 19.1 % respectively. None of these markers was correlated with PD-L1 expression. 66 % (45/68) expressed at least one immune marker, and 43 % (29/68) were "double-positive", as they expressed both immune and angiogenic markers. OS was significantly shorter for patients with PD-L1 positive pRCC. A multivariate analysis confirmed a significant association between PD-L1 expression and shorter overall survival (HR = 4.0, p = 0.01).

CONCLUSION

These results reinforce clinical data on the expected benefit of ICI in metastatic pRCC treatment, as PD-L1 expression is a factor of poor prognosis in this multicenter cohort.

Renal Cell Carcinoma of Variant Histology: Biology and Therapies

The term variant histology renal cell carcinomas (vhRCCs), also known as non-clear cell RCCs, refers to a diverse group of malignancies with distinct biologic and therapeutic considerations. The management of vhRCC subtypes is often based on extrapolating results from the more common clear cell RCC studies or basket trials that are not specific to each histology. The unique management of each vhRCC subtype necessitates accurate pathologic diagnosis and dedicated research efforts. Herein, we discuss tailored recommendations for each vhRCC histology informed by ongoing research and clinical experience.

Characterization of papillary and clear cell renal cell carcinoma through imaging mass cytometry reveals distinct immunologic profiles

Objective

To characterize and further compare the immune cell populations of the tumor microenvironment (TME) in both clear cell and papillary renal cell carcinoma (RCC) using heavy metal-labeled antibodies in a multiplexed imaging approach (imaging mass cytometry).

Materials and methods

Formalin-fixed paraffin-embedded (FFPE) baseline tumor tissues from metastatic patients with clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) were retrospectively requisitioned from an institutional biorepository. Pretreated FFPE samples from 33 RCC patients (10 ccRCC, 23 pRCC) were accessioned and stained for imaging mass cytometry (IMC) analysis. Clinical characteristics were curated from an institutional RCC database. FFPE samples were prepared and stained with heavy metal-conjugated antibodies for IMC. An 11-marker panel of tumor stromal and immune markers was used to assess and quantify cellular relationships in TME compartments. To validate our time-of-flight (CyTOF) analysis, we cross-validated findings with The Cancer Genome Atlas Program (TCGA) analysis and utilized the CIBERSORTx tool to examine the abundance of main immune cell types in pRCC and ccRCC patients.

Results

Patients with ccRCC had a longer median overall survival than did those with pRCC (67.7 vs 26.8 mo, respectively). Significant differences were identified in the proportion of CD4+ T cells between disease subtypes (ccRCC 14.1%, pRCC 7.0%, p<0.01). Further, the pRCC cohort had significantly more PanCK+ tumor cells than did the ccRCC cohort (24.3% vs 9.5%, respectively, p<0.01). There were no significant differences in macrophage composition (CD68+) between cohorts. Our results demonstrated a significant correlation between the CyTOF and TCGA analyses, specifically validating that ccRCC patients exhibit higher levels of CD4+ T cells (ccRCC 17.60%, pRCC 15.7%, p<0.01) and CD8+ T cells (ccRCC 17.83%, pRCC 11.15%, p<0.01). The limitation of our CyTOF analysis was the large proportion of cells that were deemed non-characterizable.

Conclusions

Our findings emphasize the need to investigate the TME in distinct RCC histological subtypes. We observed a more immune infiltrative phenotype in the TME of the ccRCC cohort than in the pRCC cohort, where a tumor-rich phenotype was noted. As practical predictive biomarkers remain elusive across all subtypes of RCC, further studies are warranted to analyze the biomarker potential of such TME classifications.

Immune Checkpoint Inhibitors in Renal Cell Carcinoma: Molecular Basis and Rationale for Their Use in Clinical Practice

Renal cell carcinoma (RCC) is the seventh most common cancer in men and the ninth most common cancer in women worldwide. There is plenty of evidence about the role of the immune system in surveillance against tumors. Thanks to a better understanding of immunosurveillance mechanisms, immunotherapy has been introduced as a promising cancer treatment in recent years. Renal cell carcinoma (RCC) has long been thought chemoresistant but highly immunogenic. Considering that up to 30% of the patients present metastatic disease at diagnosis, and around 20–30% of patients undergoing surgery will suffer recurrence, we need to identify novel therapeutic targets. The introduction of immune checkpoint inhibitors (ICIs) in the clinical management of RCC has revolutionized the therapeutic approach against this tumor. Several clinical trials have shown that therapy with ICIs in combination or ICIs and the tyrosine kinase inhibitor has a very good response rate. In this review article we summarize the mechanisms of immunity modulation and immune checkpoints in RCC and discuss the potential therapeutic strategies in renal cancer treatment.

Bioinformatic analysis highlights SNHG6 as a putative prognostic biomarker for kidney renal papillary cell carcinoma

PURPOSE

Kidney renal papillary cell carcinoma (KIRP) is a highly heterogeneous malignancy and current systemic therapeutic strategies are difficult to achieve a satisfactory outcome for advanced disease. Meanwhile, there is a lack of effective biomarkers to predict the prognosis of KIRP.

METHODS

Using TCGA, GTEx, UALCAN, TIMER, TIMER 2.0 and STRING databases, we analyzed the relationship of SNHG6 with KIRP subtypes, tumor-infiltrating immune cells and potential target mRNAs. Based on TCGA data, ROC curves, Kaplan-Meier survival analysis and COX regression analysis were performed to evaluate the diagnostic and prognostic value of SNHG6 in KIRP. Nomogram was used to predict 3- and 5-year disease-specific survival in KIRP patients. In addition, with the help of Genetic ontology and Gene set enrichment analysis, the biological processes and signalling pathways that SNHG6 may be involved in KIRP were initially explored.

RESULTS

In patients with KIRP, SNHG6 was significantly upregulated and associated with a more aggressive subtype (lymph node involvement, pathological stage IV, CIMP phenotype) and poor prognosis. The ROC curve showed good diagnostic efficacy (AUC value: 0.828) and the C-index of the Nomogram for predicting DSS at 3 and 5 years was 0.920 (0.898-0.941). In the immune microenvironment of KIRP, SNHG6 expression levels were negatively correlated with macrophage abundance and positively correlated with cancer-associated fibroblasts. Furthermore, SNHG6 may promote KIRP progression by regulating the expression of molecules such as AURKB, NDC80, UBE2C, NUF2, PTTG1, CENPH, SPC25, CDCA3, CENPM, BIRC5, TROAP, EZH2. Last, GSEA suggests that SNHG6 may be involved in the regulation of the PPAR signalling pathway and the SLIT/ROBO signalling pathway.

CONCLUSIONS

Our analysis suggests that a high SNHG6 expression status in KIRP is associated with a poorer prognosis for patients, and also elucidates some potential mechanisms contributing to this poorer outcome. This may provide new insights into the treatment and management of KIRP in the foreseeable future.

Comparative real-world survival outcomes of metastatic papillary and clear cell renal cell carcinoma treated with immunotherapy, targeted therapy, and combination therapy

INTRODUCTION

While there are a plethora of studies supporting novel treatment approaches in metastatic clear cell renal cell carcinoma (ccRCC), much of the data used to inform care of patients with metastatic papillary RCC (pRCC) is extrapolated from ccRCC. Several recent phase III trials have supported the use of immunotherapy (IO) and targeted therapy (TT)+IO in ccRCC, without corresponding data for pRCC. Using ccRCC as a comparison group, we sought to describe real-world trends in the utilization of systemic therapy and its impact on overall survival (OS) among patients with metastatic pRCC.

METHODS

Using the National Cancer Database (NCDB), we identified cases of metastatic pRCC and ccRCC between 2015 and 2018. Patients were stratified into groups based on histology and first-line treatments (TT, IO, TT + IO). Differences in baseline characteristics were assessed using the Kruskal-Wallis test for continuous variables, and the Chi-square or Fisher's exact test for categorical variables. Survival analysis was performed using Kaplan-Meier estimates and multivariable Cox regression analyses.

RESULTS

A total of 6,920 patients with a diagnosis of metastatic RCC were identified: 594 (8.6%) with pRCC and 6,326 (91.4%) with ccRCC. Overall, 4,710 patients received TT (455 pRCC and 4,255 ccRCC), 1,585 received IO (77 pRCC and 1,508 ccRCC), and 625 received TT+IO (62 pRCC and 563 ccRCC). Temporal trend between 2015 and 2018 revealed an increased utilization of IO and TT + IO for pRCC and ccRCC. In patients with metastatic pRCC, neither IO (HR 1.03; 95% CI 0.75-1.42) nor TT+IO (HR 0.90, 95% CI 0.63-1.28) were associated with better OS compared to TT alone. In contrast, both IO and combination TT and IO were associated with significantly better OS than TT for patients with metastatic ccRCC (IO group: hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.68-0.82; TT+IO group: HR 0.82, 95% CI 0.72-0.93). Cytoreductive nephrectomy was associated with better OS in both pRCC (HR 0.59, 95% CI 0.46-0.77) and ccRCC (HR 0.54, 95% CI 0.50-0.58).

CONCLUSIONS

Although IO and TT + IO were associated with better OS among patients with metastatic ccRCC, this same effect was not observed among patients with pRCC.

Identification of molecular subtypes based on chromatin regulator and tumor microenvironment infiltration characterization in papillary renal cell carcinoma

BACKGROUND

Papillary renal cell carcinoma (pRCC) is the second most common histological type of renal cell carcinoma. The prognosis of local pRCC is better than that of ccRCC, but the situation has changed greatly after pRCC metastasis. Chromatin regulators (CRs) are indispensable in epigenetic regulation, and their abnormal expression in tumors leads to the occurrence and development of tumor. However, the role of CRs in pRCC has not been studied yet.

MATERIALS AND METHODS

291 samples were obtained from TCGA-KIPR cohort. Unsupervised clustering analysis was utilized to divide the patients of pRCC into two subtypes. Lasso Cox regression analysis was performed to construct a CRs_score model for predicting OS. The unique characteristics of different molecular subtypes were determined by TME cell infiltration analysis, GO and KEGG analysis and drug sensitivity analysis. We also carried out drug sensitivity experiments in vitro to verify the effect of signature genes on drug sensitivity to sunitinib.

RESULTS

We described the transcriptional and genetic alteration of 19 prognosis-related CRs genes in 291 cases of TCGA-KIRP cohort. We identified two distinct molecular subtypes, which have significant differences in prognosis, clinicopathological features and tumor immune microenvironment (TME). Then, four signature genes were selected by lasso regression analysis to construct a CRs_score for predicting OS, and its predictive ability for patients with pRCC was verified. A nomogram was established to improve the clinical applicability of CRs_score. We found that there was a significant difference in the proportion of immune cell infiltration between high- and low-CRs_score. In addition, CRs_score was significantly correlated with chemosensitivity. Finally, we found that SK-RC-39 cell lines were more sensitive to sunitinib after knocking down the signature gene CDCA3, PDIA4, or SUCNR1.

CONCLUSIONS

Our comprehensive analysis of CRs gene in pRCC showed that CRs gene plays a potential role in TME, prognosis and drug resistance in pRCC. These findings may lay a foundation for further study of the regulatory role of CRs gene in pRCC, and provide a new method for evaluating prognosis and developing more effective targeted therapy.

Advanced papillary renal cell carcinoma: Epidemiology, genomic drivers, current therapies, and ongoing trials

Papillary renal cell carcinoma (PRCC) is the most common subtype of non-clear cell renal cell carcinoma. PRCC can be subdivided into types 1 and 2 based on histology, each associated with different genetic mutations. The MET gene is commonly altered in type 1 PRCC while multiple alterations are involved in type 2 PRCC. PRCC is an aggressive cancer with a predominance in male and black patients and poor prognosis. Due to its rarity, there was a lack of convincing prospective data to guide treatment; hence, therapies were previously extrapolated from clear cell renal cell carcinoma with mixed results. More recently, some phase 2 trials focused on PRCC have been promising. Tyrosine kinase inhibitor (TKI) monotherapy is considered the standard of care, and combination strategies with TKIs and immune checkpoint inhibitors are emerging. Genetic profiling and large-scale clinical trials are needed to inform targeted treatment of PRCC.

Outcomes of patients with advanced non-clear cell renal cell carcinoma treated with first-line immune checkpoint inhibitor therapy

BACKGROUND

Immune checkpoint inhibitors (ICI) have demonstrated impressive activity in metastatic clear-cell renal cell carcinoma (ccRCC) and have become standard treatment options for patients with advanced disease. Data supporting the effectiveness of ICI-based therapy in advanced non-clear cell RCC (nccRCC) is more limited.

METHODS

We performed a retrospective analysis using the International Metastatic RCC Database Consortium (IMDC) to evaluate the outcomes of patients with advanced nccRCC. Patients were classified into three groups based on first-line therapy: ICI-based therapy (monotherapy or combination), vascular endothelial growth factor (VEGF) inhibitor monotherapy, or mammalian target of rapamycin (mTOR) inhibitor monotherapy. The primary outcome was overall survival (OS). Secondary outcomes were time to treatment failure (TTF) and objective response rate (ORR). We used the Kaplan-Meier method to compare OS and TTF between treatment groups and Cox proportional hazards models to adjust for prognostic covariates.

RESULTS

We identified a total of 1145 patients with metastatic nccRCC. The most common subtype was papillary RCC (54.9%). For first-line therapy, 74.3% received VEGF monotherapy, 15% received mTOR monotherapy, and 10.7% received ICI-based therapy. Median OS in the ICI group was 28.6 months, versus 16.4 months in the VEGF group and 12.2 months in the mTOR group. Median TTF in the ICI group was 6.9 months, versus 5.0 months in the VEGF group and 3.9 months in the mTOR group. ORR was 27.2% in the ICI group, 14.5% in the VEGF group, and 9% in the mTOR group. After adjusting for the IMDC risk group, histological subtype, and age, the hazard ratio for OS was 0.57 (95% CI 0.42-0.78, p < 0.0001) for ICI versus VEGF and 0.50 (95% CI 0.36-0.71, p < 0.0001) for ICI versus mTOR.

CONCLUSIONS

In advanced nccRCC, first-line ICI-based treatment appears to be associated with improved OS compared to VEGF and mTOR targeted therapy. These results should be confirmed in prospective randomised trials.

A Systematic Review of Immune Checkpoint Inhibitors in Non-Clear-Cell Renal Cancer

Background: Immune checkpoint inhibitors (ICI) have emerged as active therapies in the management of advanced RCC. While multiple studies have shown clinical activity of ICIs in clear cell histologies, the evidence to support their use in non-clear cell (ncc) subtypes is based on smaller prospective trials and retrospective analyses. Objective: The objective of this review is to summarize the clinical outcomes of ICI-based therapies in ncc-subtypes and in tumors with sarcomatoid/rhabdoid features. Methods: We performed a systematic literature search using PubMed, Google Scholar and ASCO databases. The key-words “renal cell cancer” and “immune check point inhibitors” and equivalents were used and all original publications between July 2016 and July 2021 were included. Results: We included a total of 14 publications including two clinical trials and 12 case series. The most frequent histologies were papillary (up to 75-100%), unclassified (up to 34%) and chromophobe (up to 28%). ICI monotherapy showed some activity in both 1st and 2nd line with response rates up to 27% . ICI combination regimens yielded better activity than ICI monotherapy but, overall, a heterogeneous efficacy was noted across histologies. Overall, outcomes of ICIs were superior in tumors with sarcomatoid/rhabdoid features. Conclusion: The observed activity of ICI-based therapies was heterogeneous. Combination regimens, papillary subtype and sarcomatoid/rhabdoid features were associated with higher responses. These findings might help treatment decisions and require further validation.

Everolimus or sunitinib as first-line treatment of metastatic papillary renal cell carcinoma: A retrospective study of the GETUG group (Groupe d'Etude des Tumeurs Uro-Génitales)

BACKGROUND

Two phase II trials (NCT00688753 and NCT00541008) reported efficacy data of sunitinib and everolimus in first-line treatment of metastatic papillary renal cell carcinoma (mpRCC). Although most patients receive sunitinib or a mammalian target of rapamycin (mTOR) inhibitor in first- and second-line treatment, the optimal strategy remained unknown.

MATERIAL AND METHODS

In 23 centres of the Groupe d'Etude des Tumeurs Urogénitales group, after centralised pathological review, we analysed retrospectively progression-free survival (PFS) of patients with mpRCC treated in first-line treatment (PFS-1) with sunitinib or everolimus (primary end-point), PFS in second-line treatment (PFS-2), overall survival (OS), objective response rate, disease control rate (DCR), overall sequence and prognostic factors for OS (secondary end-points).

RESULTS

One hundred thirty-eight patients (119 men and 19 women), median age 62.5 years, with mpRCC type 1 (n = 24) or non-type 1 (n = 114), received first-line sunitinib (n = 107) or everolimus (n = 31). With a median follow-up of 92 months, we found no significant difference between the treatment groups in terms of PFS-1 (5.5 versus 6.2 months) and DCR (69% versus 83%). Ninety-eight patients received a second-line treatment, 69% with mTOR inhibitors after sunitinib and 100% with tyrosine kinase inhibitors after everolimus, with similar DCR (64% versus 58%), median PFS-2 (3.4 versus 4.8 months) and OS (16.0 versus 20.3 months). No factor was prognostic for PFS-1, whereas leukocytosis, anaemia and the time from diagnosis to first systemic therapy < 1 year were prognostic for OS. We found no prognostic difference between both pRCC subtypes. The International Metastatic Renal Cell Database Consortium risk factors were prognostic for OS.

CONCLUSION

Sunitinib and everolimus had similar efficacy in first-line treatment of patients with mpRCC.

Immune Checkpoint Inhibition in Advanced Non-Clear Cell Renal Cell Carcinoma: Leveraging Success from Clear Cell Histology into New Opportunities

Renal cell carcinoma (RCC) is a histologically heterogeneous disease with multiple subtypes. Clear cell RCC (ccRCC) represents the most common histology and has thus been easiest to study in clinical trials. Non-clear cell RCC (nccRCC) represents about 25% of RCC tumors, with fewer treatment options available, compared to ccRCC, and with poorer outcomes. Non-clear cell RCC tumors are histologically diverse, with each subtype having distinct molecular and clinical characteristics. Our understanding of nccRCC is evolving, with a gradual shift from treating nccRCC as a single entity to approaching each subtype as its own disease with unique features. Due to the scarcity of patients for study development, trials have predominantly combined all nccRCC subtypes and re-purposed drugs already approved for ccRCC, despite the decreased efficacy. We are now in the early stages of a potential paradigm shift in the treatment of nccRCC, with a rapid development of clinical studies with a focus on this subset of tumors. Investigators have launched trials focused on the molecular drivers of tumorigenesis using targeted therapies. Harboring the immunogenicity of some nccRCC subtypes, and based on promising retrospective studies, clinicians have also devised multiple trials using immune checkpoint inhibitors (ICIs), both alone or in combination with targeted therapies, for nccRCC subtypes. We highlight the promising completed and ongoing studies employing ICIs that will likely continue to improve outcomes in patients with nccRCC and propose future potential immunotherapeutic avenues.

Checkpoint inhibitors in metastatic papillary renal cell carcinoma

Papillary Renal Cell Carcinoma (pRCC) is the most common non-clear cell RCC (nccRCC) and a distinct entity, although heterogenous, associated with poor outcomes. The treatment landscape of metastatic pRCC (mpRCC) relied so far on targeted therapies, mimicking previous developments in metastatic clear-cell renal cell carcinoma. However, antiangiogenics as well as mTOR inhibitors retain only limited activity in mpRCC. As development of immune checkpoint inhibitors (ICI) is now underway in patients with mpRCC, we aimed at discussing early activity data and potential for future therapeutic strategies in monotherapy or combination. Expression of immune checkpoints such as PD-L1 and infiltrative immune cells in pRCC could provide insights into their potential immunogenicity, although this is currently poorly described. Based on retrospective and prospective data, efficacy of ICI as single agent remains limited. Combinations with tyrosine-kinase inhibitors, notably with anti-MET inhibitors, harbor promising response rates and may enter the standard of care in untreated patients. Collaborative work is needed to refine the molecular and immune landscape of pRCC, and pursue efforts to set up predictive biomarker-driven clinical trials in these rare tumors.

Response to systemic therapy in fumarate hydratase-deficient renal cell carcinoma

PURPOSE

Fumarate hydratase-deficient (FHdef) renal cell carcinoma (RCC) is a rare entity associated with the hereditary leiomyomatosis and RCC syndrome with no standard therapy approved. The aim of this retrospective study was to evaluate the efficacy of different systemic treatments in this population.

METHODS

We performed a multicentre retrospective analysis of Fhdef RCC patients to determine the response to systemic treatments. The endpoints were objective response rate (ORR), time-to-treatment failure (TTF), and overall survival (OS). The two latter were estimated using the Kaplan-Meier method.

RESULTS

Twenty-four Fhdef RCC patients were identified, and 21 under systemic therapy were included in the analysis: ten received cabozantinib, 14 received sunitinib, nine received "other antiangiogenics" (sorafenib, pazopanib, and axitinib), three received erlotinib-bevacizumab (E-B), three received mTOR inhibitors, and 11 received immune checkpoint blockers (ICBs). ORR for treatments were 50% for cabozantinib, 43% for sunitinib, 63% for "other antiangiogenics," and 30% for E-B, whereas ORR was 0% for mTOR inhibitors and 18% for ICBs. The median TTF (mTTF) was significantly higher with antiangiogenics (11.6 months) than with mTOR inhibitors (4.4 months) or ICBs (2.7 months). In the first-line setting, antiangiogenics presented a higher ORR compared with nivolumab-ipilimumab (64% versus 25%) and a significantly superior mTTF (11.0 months vs 2.5 months; p = 0.0027). The median OS from the start of the first systemic treatment was 44.0 months (95% confidence interval: 13.0-95.0).

CONCLUSIONS

We report the first European retrospective study of Fhdef RCC patients treated with systemic therapy with a remarkably long median OS of 44.0 months. Our results suggest that antiangiogenics may be superior to ICB/mTOR inhibitors in this population.

Systemic Therapies for the Management of Non-Clear Cell Renal Cell Carcinoma: What Works, What Doesn't, and What the Future Holds

Non-clear cell renal cell carcinoma (nccRCC) is a broad term that refers to a diverse group of tumors, each with its own distinct biologic and therapeutic profile. The management of nccRCCs is often based on extrapolating data from clinical trials in the more common clear cell renal cell carcinoma, but our emerging prospective and retrospective clinical experience in nccRCC allows us to make more precise recommendations tailored to each histology. The systemic therapy options for metastatic nccRCC include targeted therapies such as tyrosine kinase inhibitors, immune checkpoint inhibitors, and, for specific rare subtypes, cytotoxic chemotherapy. Each nccRCC histology may respond differently to these regimens, which makes accurate pathologic diagnosis imperative. In the present review, we discuss the available clinical and biological data that can help guide systemic therapy recommendations for specific nccRCC subtypes.