Combination Immune Checkpoint Blockade Regimens for Previously Untreated Metastatic Renal Cell Carcinoma: The Winship Cancer Institute of Emory University Experience

Introduction

There are three combination immune checkpoint inhibitor (ICI)-based regimens in the first-line setting for metastatic renal cell carcinoma (mRCC). Currently, there is limited real-world data for clinical outcomes and toxicity in mRCC patients treated with first-line ICI-based regimens.

Methods

We performed a retrospective review of 49 mRCC patients treated with ICI-based combination regimens in the standard of care setting at the Winship Cancer Institute of Emory University from 2015-2020. We collected baseline data from the electronic medical record including demographic information and disease characteristics. Immune-related adverse events (irAEs) were collected from clinic notes and laboratory values. The primary clinical outcomes measured were overall survival (OS), progression-free survival (PFS), and objective response rate (ORR).

Results

The median age was 65 years, and most patients (80%) were males. The majority were White (86%) and had clear cell RCC (83%). Most patients had an Eastern Cooperative Oncology Group (ECOG) performance status score of 0 (43%) or 1 (45%). Approximately one-half (49%) had at least three sites of distant metastatic disease. Most patients (88%) received nivolumab and ipilimumab. More than one-half (53%) of patients experienced an irAE, with 13 (27%) patients having treatment delayed and 18% discontinuing treatment for toxicity. The median OS was not reached, and the median PFS was 8.0 months per a Kaplan-Meier estimation. More than half of patients (53%) had a PFS > 6 months, and 22% had PFS > 1 year. The ORR was 33% for the entire cohort, and 7% of patients had a complete response.

Conclusion

We presented real-world efficacy and toxicity data for front-line ICI combination treatment regimens. The ORR and median PFS were lower in our cohort of patients compared to the available data in the clinical trial setting. This was likely because of more advanced disease in this study. Future studies should provide additional data that will allow comparisons between different ICI combination regimens for untreated mRCC.

Analysis of Toxicity and Clinical Outcomes in Full Versus Reduced Starting Dose Cabozantinib in Metastatic Renal Cell Carcinoma Patients

BACKGROUND

Full dose cabozantinib for metastatic renal cell carcinoma (mRCC) is 60 mg, but adverse events (AEs) may require dose reductions. Limited data exist comparing efficacy among cabozantinib doses. We compared AEs and clinical outcomes in mRCC patients treated with full vs. reduced starting cabozantinib dose.

METHODS

We performed a retrospective analysis of 87 mRCC patients treated with cabozantinib at Winship Cancer Institute from 2016 to 2019. Overall survival (OS), progression-free survival (PFS), and objective response (OR) rate measured clinical outcomes. AEs were collected from clinic notes and the most common were hypertension, mucositis/hand-foot skin reaction (HFSR), or gastrointestinal toxicity. Univariate analysis (UVA) between starting doses and AEs with clinical outcomes was performed using logistic regression model. Multivariable analysis was also performed using Cox proportional hazard model.

RESULTS

Most patients were men (71%) with clear-cell RCC (72%). The majority were IMDC intermediate (58%) or poor (35%) risk. One third received first-line cabozantinib and 64% had ≥3 baseline metastatic sites. Most patients (68%) required dose reduction from 60 mg or started at reduced dose without escalation. Reduced dose patients were more likely to have ≥3 distant metastatic sites (70% vs. 58%) and ≥2 prior lines of systemic therapy (50% vs. 40%) compared to full dose patients. UVA revealed a trend towards shorter OS (HR: 1.78, P = .095), PFS (HR: 1.50, P = .107), and lower chance of OR (HR:0.42, P = .149) among reduced dose patients. This trend did not hold in Multivariable analysis (OS HR: 1.20, P = .636; PFS HR: 1.23, P = .4662). Mucositis/HFSR and hypertension were significantly associated with improved outcomes in UVA.

CONCLUSIONS

Although we found a trend favoring full dose cabozantinib, this is likely due to worse baseline disease characteristics among patients starting on a reduced dose. Hypertension and mucositis/HFSR may be associated with improved outcomes. Larger studies are warranted to validate these findings.

Advances in Knowledge and Management of Immune-Related Adverse Events in Cancer Immunotherapy

Immune-oncologic (IO) therapy has revolutionized the treatment and management of oncologic disease. Immunotherapy functions by enhancing the host immune-systems ability to endogenously clear malignant cells, however, this activation can also lead to immune-mediated damage to healthy native tissues. These side effects are known as immune-related adverse events or irAEs and can even present with phenotypes similar to autoimmune diseases. IrAEs are the major consequence of checkpoint inhibitors and can have a significant impact on a patient's cancer treatment and long-term quality of life. The management of these irAEs follows a similar approach to autoimmune diseases. More specifically, the management is akin to that of autoimmune disease exacerbations. While there is an array of immune-suppressing agents that can be used, steroids, immunomodulators and IO discontinuation are cornerstones of irAE management. The exact approach and dosing are based on the severity and subtype of irAE presented. Within recent years, there has been a push to better prevent and manage irAEs when they arise. There has been an additional effort to increase the number of steroid-sparing agents available for irAE treatment given the consequences of long-term steroid therapy as well as patient contraindications to steroids. The goals of this review are to summarize irAE management, highlight significant advances made in recent years and emphasize the future directions that will optimize the use of IO therapy in oncology.

Case Report: Exceptional Response to Nivolumab Plus Ipilimumab in a Young Woman With TFE3-SFPQ Fusion Translocation-Associated Renal Cell Carcinoma

Translocation-associated renal cell carcinoma (tRCC) is a rare, aggressive malignancy that primarily affects children and young adults. There is no clear consensus on the most effective treatment for tRCC and there are no biomarkers of response to treatments in these patients. We present a case of a 23 year-old female with metastatic tRCC to the lungs who was started on treatment with nivolumab and ipilimumab. She had a complete radiographic response to treatment and has been progression-free for over 18 months. Immunofluorescence imaging performed on the baseline primary tumor sample showed significant intratumoral immune infiltration. Importantly, these cells are present in niches characterized by TCF1+ CD8+ T cells. Histopathologic investigation showed the presence of lymphocytes in the fibrovascular septae and foci of lymphovascular invasion. Furthermore, lymphovascular invasion and intratumor niches with TCF1+ CD8+ T cells may predict a favorable response to treatment with nivolumab and ipilimumab. These findings have significant clinical relevance given that immune checkpoint inhibitors are approved for several malignancies and predictive biomarkers for response to treatment are lacking. Importantly, the identification of these TCF1+ CD8+ T cells may guide treatment for patients with tRCC, which is a rare malignancy without a consensus first-line treatment option.

Efficacy of enfortumab vedotin in advanced urothelial cancer: Analysis from the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study

BACKGROUND

Enfortumab vedotin (EV) is a novel antibody-drug conjugate approved for advanced urothelial cancer (aUC) refractory to prior therapy. In the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study, the authors looked at the experience with EV in patient subsets of interest for which activity had not been well defined in clinical trials.

METHODS

UNITE was a retrospective study of patients with aUC treated with recently approved agents. This initial analysis focused on patients treated with EV. Patient data were abstracted from chart reviews by investigators at each site. The observed response rate (ORR) was investigator-assessed for patients with at least 1 post-baseline scan or clear evidence of clinical progression. ORRs were compared across subsets of interest for patients treated with EV monotherapy.

RESULTS

The initial UNITE analysis included 304 patients from 16 institutions; 260 of these patients were treated with EV monotherapy and included in the analyses. In the monotherapy cohort, the ORR was 52%, and it was >40% in all reported subsets of interest, including patients with comorbidities previously excluded from clinical trials (baseline renal impairment, diabetes, and neuropathy) and patients with fibroblast growth factor receptor 3 (FGFR3) alterations. Progression-free survival and overall survival were 6.8 and 14.4 months, respectively. Patients with a pure urothelial histology had a higher ORR than patients with a variant histology component (58% vs 42%; P = .06).

CONCLUSIONS

In a large retrospective cohort, responses to EV monotherapy were consistent with data previously reported in clinical trials and were also observed in various patient subsets, including patients with variant histology, patients with FGFR3 alterations, and patients previously excluded from clinical trials with an estimated glomerular filtration rate < 30 mL/min and significant comorbidities.

LAY SUMMARY

Enfortumab vedotin, approved by the Food and Drug Administration in 2019, is an important new drug for the treatment of patients with advanced bladder cancer. This study looks at the effectiveness of enfortumab vedotin as it has been used at multiple centers since approval, and focuses on important patient populations previously excluded from clinical trials. These populations include patients with decreased kidney function, diabetes, and important mutations. Enfortumab vedotin is effective for treating these patients. Previously reported clinical trial data have been replicated in this real-world setting, and support the use of this drug in broader patient populations.

Body Composition as an Independent Predictive and Prognostic Biomarker in Advanced Urothelial Carcinoma Patients Treated with Immune Checkpoint Inhibitors

BACKGROUND

Several immune checkpoint inhibitors (ICIs) are approved for the treatment of advanced urothelial carcinoma (UC). There are limited biomarkers for ICI-treated patients with UC. We investigated the association between body composition and clinical outcomes in ICI-treated UC patients.

MATERIALS AND METHODS

We conducted a retrospective analysis of 70 ICI-treated patients with advanced UC at Winship Cancer Institute from 2015 to 2020. Baseline computed tomography images within 2 months of ICI initiation were collected at mid-L3 and muscle and fat compartments (subcutaneous, intermuscular, and visceral) were segmented using SliceOMatic v5.0 (TomoVision, Magog, Canada). A prognostic body composition risk score (high: 0-1, intermediate: 2-3, or low-risk: 4) was created based on the β coefficient from the multivariate Cox model (MVA) following best-subset variable selection. Our body composition risk score was skeletal muscle index (SMI) + 2 × attenuated skeletal muscle (SM) mean + visceral fat index (VFI). Concordance statistics (C-statistics) were used to quantify the discriminatory magnitude of the predictive model.

RESULTS

Most patients (70%) were men and the majority received ICIs in the second- (46%) or third-line (21%) setting. High-risk patients had significantly shorter overall survival (OS; hazard ratio [HR], 6.72; p < .001), progression-free survival (HR, 5.82; p < .001), and lower chance of clinical benefit (odds ratio [OR], 0.02; p = .003) compared with the low-risk group in MVA. The C-statistics for our body composition risk group and myosteatosis analyses were higher than body mass index for all clinical outcomes.

CONCLUSION

Body composition variables such as SMI, SM mean, and VFI may be prognostic and predictive of clinical outcomes in ICI-treated patients with UC. Larger, prospective studies are warranted to validate this hypothesis-generating data.

IMPLICATIONS FOR PRACTICE

This study developed a prognostic body composition risk scoring system using radiographic biomarkers for patients with bladder cancer treated with immunotherapy. The study found that the high-risk patients had significantly worse clinical outcomes. Notably, the study's model was better at predicting outcomes than body mass index. Importantly, these results suggest that radiographic measures of body composition should be considered for inclusion in updated prognostic models for patients with urothelial carcinoma treated with immunotherapy. These findings are useful for practicing oncologists in the academic or community setting, particularly given that baseline imaging is routine for patients starting on treatment with immunotherapy.

Body Composition Variables as Radiographic Biomarkers of Clinical Outcomes in Metastatic Renal Cell Carcinoma Patients Receiving Immune Checkpoint Inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICI) have revolutionized the treatment of metastatic renal cell carcinoma (mRCC). Biomarkers for mRCC patients treated with ICI are limited, and body composition is underutilized in mRCC. We investigated the association between body composition and clinical outcomes in ICI-treated mRCC patients.

METHODS

We performed a retrospective analysis of 79 ICI-treated mRCC patients at Winship Cancer Institute from 2015-2020. Baseline CT images were collected at mid-L3 and segmented using SliceOMatic v5.0 (TomoVision). Density of skeletal muscle (SM), subcutaneous fat, inter-muscular fat, and visceral fat were measured and converted to indices by dividing by height(m)2 (SMI, SFI, IFI, and VFI, respectively). Total fat index (TFI) was defined as the sum of SFI, IFI, and VFI. Patients were characterized as high versus low for each variable at gender-specific optimal cuts using overall survival (OS) as the primary outcome. A prognostic risk score was created based on the beta coefficient from the multivariable Cox model after best subset variable selection. Body composition risk score was calculated as IFI + 2*SM mean + SFI and patients were classified as poor (0-1), intermediate (2), or favorable risk (3-4). Kaplan-Meier method and Log-rank test were used to estimate OS and PFS and compare the risk groups. Concordance statistics (C-statistics) were used to measure the discriminatory magnitude of the model.

RESULTS

Most patients were male (73%) and most received ICI as first (35%) or second-line (51%) therapy. The body composition poor-risk patients had significantly shorter OS (HR: 6.37, p<0.001), PFS (HR: 4.19, p<0.001), and lower chance of CB (OR: 0.23, p=0.044) compared to favorable risk patients in multivariable analysis. Patients with low TFI had significantly shorter OS (HR: 2.72, p=0.002), PFS (HR: 1.91, p=0.025), and lower chance of CB (OR: 0.25, p=0.008) compared to high TFI patients in multivariable analysis. The C-statistics were higher for body composition risk groups and TFI (all C-statistics ≥ 0.598) compared to IMDC and BMI.

CONCLUSIONS

Risk stratification using the body composition variables IFI, SM mean, SFI, and TFI may be prognostic and predictive of clinical outcomes in mRCC patients treated with ICI. Larger, prospective studies are warranted to validate this hypothesis-generating data.

Immune-Related Adverse Events as Clinical Biomarkers in Patients with Metastatic Renal Cell Carcinoma Treated with Immune Checkpoint Inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are an important treatment for metastatic renal cell carcinoma (mRCC). These agents may cause immune-related adverse events (irAEs), and the relationship between irAEs and outcomes is poorly understood. We investigated the association between irAEs and clinical outcomes in patients with mRCC treated with ICIs.

METHODS

We performed a retrospective study of 200 patients with mRCC treated with ICIs at Winship Cancer Institute from 2015 to 2020. Data on irAEs were collected from clinic notes and laboratory values and grades were determined using Common Terminology Criteria in Adverse Events version 5.0. The association with overall survival (OS) and progression-free survival (PFS) was modeled by Cox proportional hazards model. Logistic regression models were used to define odds ratios (ORs) for clinical benefit (CB). Landmark analysis and extended Cox models were used to mitigate lead-time bias by treating irAEs as a time-varying covariate.

RESULTS

Most patients (71.0%) were male, and one-third of patients (33.0%) experienced at least one irAE, most commonly involving the endocrine glands (13.0%), gastrointestinal tract (10.5%), or skin (10.0%). Patients who experienced irAEs had significantly longer OS (hazard ratio [HR], 0.52; p = .013), higher chance of CB (OR, 2.10; p = .023) and showed a trend toward longer PFS (HR, 0.71; p = .065) in multivariate analysis. Patients who had endocrine irAEs, particularly thyroid irAEs, had significantly longer OS and PFS and higher chance of CB. In a 14-week landmark analysis, irAEs were significantly associated with prolonged OS (p = .045). Patients who experienced irAEs had significantly longer median OS (44.5 vs. 18.2 months, p = .005) and PFS (7.5 vs. 3.6 months, p = .003) without landmark compared with patients who did not.

CONCLUSION

We found that patients with mRCC treated with ICIs who experienced irAEs, particularly thyroid irAEs, had significantly improved clinical outcomes compared with patients who did not have irAEs. This suggests that irAEs may be effective clinical biomarkers in patients with mRCC treated with ICIs. Future prospective studies are warranted to validate these findings.

IMPLICATIONS FOR PRACTICE

This study found that early onset immune-related adverse events (irAEs) are associated with significantly improved clinical outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with immune checkpoint inhibitors (ICIs). In this site-specific irAE analysis, endocrine irAEs, particularly thyroid irAEs, were significantly associated with improved clinical outcomes. These results have implications for practicing medical oncologists given the increasing use of ICIs for the treatment of mRCC. Importantly, these results suggest that early irAEs and thyroid irAEs at any time on treatment with ICIs may be clinical biomarkers of clinical outcomes in patients with mRCC treated with ICIs.

Racial Differences in Clinical Outcomes for Metastatic Renal Cell Carcinoma Patients Treated With Immune-Checkpoint Blockade

BACKGROUND

Immune-checkpoint-inhibitors (ICIs) have become the cornerstone of metastatic renal-cell-carcinoma (mRCC) therapy. However, data are limited regarding clinical outcomes by race. In this study, we compared the real-world outcomes between African American (AA) and Caucasian mRCC patients treated with ICIs.

METHODS

We performed a retrospective study of 198 patients with mRCC who received ICI at the Emory Winship Cancer Institute from 2015-2020. Clinical outcomes were measured by overall survival (OS), progression-free survival (PFS), and overall response rate (ORR) defined as a complete or partial response maintained for at least 6 months per response evaluation criteria in solid tumors version 1.1. Univariate and multivariable analyses were carried out for OS and PFS by Cox proportional-hazard model and ORR by logistical-regression model. Descriptive statistics compared rates of immune-related adverse events (irAEs) and non-clear-cell-RCC (nccRCC) histology were assessed using Chi-square test.

RESULTS

Our cohort was comprised of 38 AA and 160 Caucasian patients. Most were diagnosed with clear-cell-RCC (ccRCC) (78%) and more than half received (57%) PD-1/PD-L1 monotherapy. Most patients were intermediate or poor-risk groups (83%). Comparing to Caucasians, our AA cohort contained more females and nccRCC cases. Kaplan-Meier method showed AAs had no statistically different median OS (17 vs 25 months, p=0.368) and PFS (3.1 vs 4.4 months, p=0.068) relative to Caucasian patients. On multivariable analysis, AA patients had significantly shorter PFS (HR=1.52, 95% CI: 1.01-2.3, p=0.045), similar ORR (OR=1.04, 95% CI: 0.42-2.57, p=0.936) and comparable OS (HR=1.09, 95% CI: 0.61-1.95, p=0.778) relative to Caucasians.

CONCLUSIONS

Our real-world analysis of ICI-treated mRCC patients showed that AAs experienced shorter PFS but similar OS relative to Caucasians. This similarity in survival outcomes is reassuring for the use of ICI amongst real-world patient populations, however, the difference in treatment response is poorly represented in early outcomes data from clinical trials. Thus, the literature requires larger prospective studies to validate these findings.

Symptomatic methemoglobinemia in a patient with metastatic clear cell renal cell carcinoma treated with pembrolizumab and axitinib combination therapy: a case report

Background

Combination regimens that include immune checkpoint (ICI) and vascular endothelial growth factor (VEGF) inhibition have opened the door to new treatment opportunities for patients with metastatic renal cell carcinoma (mRCC). While these treatment options have provided improved tolerability and better outcomes compared to older regimens, many patients still experience a myriad of treatment-related adverse events. Given that these regimens were recently approved for mRCC, the complete side effect profile may not be fully elucidated yet.

Case presentation

We report a case of a 73-year old White male with mRCC who was managed with an ICI-VEGF inhibitor combination regimen. He experienced a partial response (Fig. 1) but had side effects including symptomatic cyanosis diagnosed as methemoglobinemia which led to treatment discontinuation. Upon holding his therapy, his methemoglobinemia and cyanosis resolved.

Conclusions

Combination VEGF-ICI therapy provide novel regimens for advanced solid tumor malignancies including mRCC. While shown to have improved efficacy in clinical trials, it is crucial that oncologists uncover the full side effect profile of these novel agents especially as their use becomes more standard in the management of advanced malignancies. To our knowledge, this is the first reported case of a patient experiencing symptomatic methemoglobinemia as an adverse event associated with a VEGF-ICI combination regimen. While the cause of this side effect is unclear, in this paper we attempt to elucidate a process that is in line with the mechanism of action of these therapies to explain how these agents, specifically the axitinib, could have caused the methemoglobin to rise to a symptomatic level.