Special populations in metastatic renal cell carcinoma

PURPOSE OF REVIEW

This review focuses on special populations poorly represented in current evidence-based practice for metastatic renal cell carcinoma (mRCC). This includes the elderly and frail, patients on immunosuppression or with autoimmune diseases, patients with brain, liver, and/or bone metastases, and RCC with sarcomatoid features.

RECENT FINDINGS

Certain populations are poorly represented in current trials for mRCC. Patients with central nervous system (CNS) metastases are often excluded from first-line therapy trials. Modern doublet systemic therapy appears to benefit patients with bone or liver metastases, but data supporting this conclusion is not robust. Post-hoc analyses on patients with sarcomatoid differentiation have shown improved response to modern doublet therapy over historical treatments. The elderly are underrepresented in current clinical trials, and most trials exclude all but high-performing (nonfrail) patients, though true frailty is likely poorly captured using the current widely adopted indices. It is difficult to make conclusions about the efficacy of modern therapy in these populations from subgroup analyses. Data from trials on other malignancies in patients with autoimmune diseases or solid organ transplant recipients on immunosuppression suggest that immune checkpoint inhibitors (ICIs) may still have benefit, though at the risk of disease flare or organ rejection. The efficacy of ICIs has not been demonstrated specifically for RCC in this group of patients.

SUMMARY

The elderly, frail, and immunosuppressed, those with tumors having aggressive histologic features, and patients with brain, bone, and/or liver metastases represent the populations least understood in the modern era of RCC treatment.

Advances in non-clear cell renal cell carcinoma management: From heterogeneous biology to treatment options

Non-clear cell renal cell carcinoma (nccRCC) makes up nearly one quarter of all RCC subtypes, commonly impacts younger patients, and is often metastatic at presentation. Compared to clear-cell RCC (ccRCC), nccRCC typically has a worse prognosis in the metastatic setting, with overall survival durations that are ~10 months shorter. The nccRCC consists of a wide range of different histological subtypes, the majority of which are composed of papillary, chromophobe, renal medullary carcinoma, translocation RCC, collecting duct carcinoma and unclassified RCC. Most clinical trials have either excluded or only included small numbers of patients with nccRCC; owing to the lack of prospective studies focusing on this population, data on response rates and survival outcomes are lacking. NccRCC treatment is a nascent field with various therapeutic modalities and combinations under investigation, often based on data extrapolated from therapeutic studies in ccRCC. We herein review the use and outcomes of cytotoxic chemotherapy, various combination modalities of tyrosine kinase inhibitors and immune checkpoint inhibitors, and targeted agents. We discuss active ongoing clinical trials for patients with nccRCC and future directions in the treatment of this rare disease. Historically, treatment for nccRCC has been adopted from the standard of care for patients with ccRCC, although these treatments are less effective in the nccRCC population. As we begin to understand the underlying biology of these tumors, clinical trials have been able to slowly accrue and include more patients with various subtypes of nccRCC. There remains much room for improvement in this area of need, but there is hope on the horizon.

SETD2 Loss and ATR Inhibition Synergize to Promote cGAS Signaling and Immunotherapy Response in Renal Cell Carcinoma

PURPOSE

Immune checkpoint blockade (ICB) demonstrates durable clinical benefits in a minority of patients with renal cell carcinoma (RCC). We aimed to identify the molecular features that determine the response and develop approaches to enhance it.

EXPERIMENTAL DESIGN

We investigated the effects of SET domain-containing protein 2 (SETD2) loss on the DNA damage response pathway, the cytosolic DNA-sensing pathway, the tumor immune microenvironment, and the response to ataxia telangiectasia and rad3-related (ATR) and checkpoint inhibition in RCC.

RESULTS

ATR inhibition activated the cyclic GMP-AMP synthase (cGAS)-interferon regulatory factor 3 (IRF3)-dependent cytosolic DNA-sensing pathway, resulting in the concurrent expression of inflammatory cytokines and immune checkpoints. Among the common RCC genotypes, SETD2 loss is associated with preferential ATR activation and sensitizes cells to ATR inhibition. SETD2 knockdown promoted the cytosolic DNA-sensing pathway in response to ATR inhibition. Treatment with the ATR inhibitor VE822 concurrently upregulated immune cell infiltration and immune checkpoint expression in Setd2 knockdown Renca tumors, providing a rationale for ATR inhibition plus ICB combination therapy. Setd2-deficient Renca tumors demonstrated greater vulnerability to ICB monotherapy or combination therapy with VE822 than Setd2-proficient tumors. Moreover, SETD2 mutations were associated with a higher response rate and prolonged overall survival in patients with ICB-treated RCC but not in patients with non-ICB-treated RCC.

CONCLUSIONS

SETD2 loss and ATR inhibition synergize to promote cGAS signaling and enhance immune cell infiltration, providing a mechanistic rationale for the combination of ATR and checkpoint inhibition in patients with RCC with SETD2 mutations.

Management of Brain Metastases in Metastatic Renal Cell Carcinoma

The development of brain metastases is a poor prognostic indicator in renal cell carcinoma. Regular imaging and clinical examinations are necessary to monitor the brain before or during systemic therapy. Central nervous system-targeted radiation therapy, including stereotactic radiosurgery, whole-brain radiation therapy, and surgical resection, is a standard treatment option. Clinical trials are currently investigating the role of targeted therapy and immune checkpoint inhibitor combinations in treating brain metastases and decreasing intracranial disease progression.

Abstract 5788: Single-cell and spatial transcriptomic mapping of human renal cell carcinoma brain metastases uncovers actionable immune-resistance targets

Introduction: The discovery of immune checkpoint inhibitors has revolutionized metastatic renal cell carcinoma (RCC) treatment. However, in patients with RCC brain metastases, response rates are low and survival outcomes poor. To understand the tumor microenvironmental differences between primary kidney tumors, extracranial metastases, and brain metastases, we developed a detailed single-cell atlas of RCC brain metastases along with their matched extracranial and primary tumors.

Methods: We performed single-nucleus RNA-seq on 27 samples (nearly 200,000 cells) from RCC patients; samples included 14 brain metastases, 8 matched primary kidney tumors, and 5 matched extracranial metastases. We performed multiplex IHC to validate selected transcriptomic findings. We used Nanostring CosMx 960-plex RNA spatial molecular imaging technique on selected samples to validate cellular interactions in a spatial context.

Results: We established a multi-tissue single-cell atlas of RCC brain metastases by identifying 9 major and 37 minor malignant, immune, and stromal cell clusters. Brain metastases had higher neuronal and glial cells interacting with immune and tumor cells. Brain metastasis tumor cells were also transcriptomically reprogrammed to adapt to the brain microenvironment through enrichment of MYC targets, MTORC1 signaling, epithelial-mesenchymal transition, fatty-acid metabolism, oxidative phosphorylation, and reactive oxygen species pathways. Moreover, cell-to-cell communication and downstream target gene expression analyses showed that brain metastasis tumor cells expressed ligands and receptors that induce tumor cell proliferation in both autocrine and paracrine fashions. Among T-cell populations, we found fewer proliferating cytotoxic T lymphocytes in the brain than in other sites. Moreover, T cells in brain metastases expressed higher levels of several targetable inhibitory checkpoints than did extracranial metastases. In addition, we found that naïve/memory T cells in brain metastases were a favorable prognostic marker for overall survival after craniotomy. Our characterization of myeloid cell populations across the 3 disease sites found fewer dendritic cells and monocytes in the brain compared to other sites. Macrophages in brain metastases more highly expressed an M2 immunosuppressive gene signature than did those in primary RCC tumors.

Conclusion: Our findings from the largest single-cell atlas of RCC brain metastases with matched primary and extracranial metastases suggest several unique targetable, immunosuppressive biological mechanisms in the brain microenvironment. These results provide a foundation for a deeper understanding of RCC brain metastasis biology and can serve as a resource for the scientific community to further explore therapeutically targetable tumor and immune-related mechanisms.

Citation Format: Elshad Hasanov, Truong Nguyen Anh Lam, Jerome Lin, Patrick K. Reville, Merve Hasanov, Anna K. Casasent, David Shih, Sahin Hanalioglu, Mehmet Asim Bilen, Omar Alhalabi, Berrin Babaoglu, Baylar Baylarov, Adeboye O. Osunkoya, Lisa M. Norberg, Joy Gumin, Tuan M. Tran, Jianzhuo Li, Anh G. Hoang, Haidee D. Chancoco, Brittany C. Parker Kerrigan, Erika J. Thompson, Betty YS Kim, Dima Suki, Melike Mut, Figen Soylemezoglu, Giannicola Genovese, Kadir C. Akdemir, Hussain A. Tawbi, Nizar M. Tannir, Florencia McAllister, Michael A. Davies, Padmanee Sharma, Jason Huse, Frederick Lang, Nicholas Navin, Eric Jonasch. Single-cell and spatial transcriptomic mapping of human renal cell carcinoma brain metastases uncovers actionable immune-resistance targets [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5788.

Phase 1b/2 study of combination 177Lu girentuximab plus cabozantinib and nivolumab in treatment naïve patients with advanced clear cell RCC

TPS749

Background: Complete response (CR) is still a rare event in patients with advanced clear cell renal cell carcinoma (ccRCC). The combination of nivolumab plus cabozantinib was recently approved for the first-line treatment of ccRCC based on the CheckMate 9ER phase 3 study demonstrating improved progression-free survival (PFS) and objective response rate (ORR) in comparison to sunitinib. However, the CR rate was only 9%. Since the anti-tumor effects of immune checkpoint inhibitors are dependent on the presence of activated tumor-infiltrating T cells, drugs that could synergize with T cells’ anti-tumor activity can allow us to improve CR rates. Activation of the cGAS-STING pathway which is induced by radiation-induced DNA damage, is one promising mechanism that has been investigated. Many studies have shown that radiation treatment augments immune checkpoint inhibition. However, it is not always possible to radiate all metastatic lesions. Therefore, targeted peptide receptor radionuclide therapies, have been developed by conjugating radioisotopes to receptor binding analogs targeting specific cancer cell surface proteins, thereby delivering targeted radiation to cancer cells in the body with minimal damage to surrounding healthy cells. 177Lu girentuximab is the first antibody-radioisotope designed for ccRCC, targeting carbonic anhydrase 9-expressing cells, which includes >90% of ccRCC. It has been tested in metastatic ccRCC as a single agent and shown to be safe and effective in stabilizing disease in 57% of pts. In this study, we hypothesize that 177Lu girentuximab-induced DNA damage will potentiate the STING pathway, and this activation will synergize with nivolumab and cabozantinib to promote trafficking and infiltration of activated T cells to tumors and achieve higher CR rates. Methods: Up to 100 patients with treatment naïve, biopsy-proven ccRCC with adequate organ/marrow function with ≥1 evaluable lesion by RECIST 1.1 will be enrolled. A 5-patient safety lead-in will evaluate myelosuppression. Ongoing safety, and futility monitoring will employ a Bayesian approach. The sample size was chosen for reasonable operating characteristics to distinguish a CR rate (primary endpoint) of 18% as better than 9% using a beta(0.09, 0.91) prior. Secondary endpoints are ORR, PFS by RECIST 1.1, and overall survival. 177Lu-girentuximab 1480 MBq/m2 (61% of single agent MTD) will be administered every 12 weeks for up to 3 cycles. Starting with the second cycle, nivolumab and cabozantinib will be added at standard dose. To explore the effects of the treatment on inducing activated T cell infiltration, patients will undergo pre/post-treatment PET scan with [18F]F-AraG radiotracer as well as biopsies for single cell, spatial transcriptomics and proteomics studies. This investigator initiated trial is supported by Telix Pharmaceuticals and DOD grant W81XWH-22-1-0456.

Immune Checkpoint Therapy Combinations in Adult Advanced MiT Family Translocation Renal Cell Carcinomas

BACKGROUND

There remains a paucity of data regarding the efficacy of immune checkpoint therapy (ICT) combinations ± vascular endothelial growth factor (VEGF) targeted therapy (TT) in translocation renal cell carcinoma (tRCC).

METHODS

This is a retrospective study of patients with advanced tRCC treated with ICT combinations at 11 centers in the US, France, and Belgium. Only cases with confirmed fluorescence in situ hybridization (FISH) were included. Objective response rates (ORR) and progression-free survival (PFS) were assessed by RECIST, and overall survival (OS) was estimated by Kaplan-Meier methods.

RESULTS

There were 29 patients identified with median age of 38 (21-70) years, and F:M ratio 0.9:1. FISH revealed TFE3 and TFEB translocations in 22 and 7 patients, respectively. Dual ICT and ICT + VEGF TT were used in 18 and 11 patients, respectively. Seventeen (59%) patients received ICT combinations as first-line therapy. ORR was 1/18 (5.5%) for dual ICT and 4/11 (36%) for ICT + VEGF TT. At a median follow-up of 12.9 months, median PFS was 2.8 and 5.4 months in the dual ICT and ICT + VEGF TT groups, respectively. Median OS from metastatic disease was 17.8 and 30.7 months in the dual ICT and ICT + VEGF TT groups, respectively.

CONCLUSION

In this retrospective study of advanced tRCC, limited response and survival were seen after frontline dual ICT combination therapy, while ICT + VEGF TT therapy offered some efficacy. Due to the heterogeneity of tRCC, insights into the biological underpinnings are necessary to develop more effective therapies.

Efficacy of Cabozantinib in Metastatic MiT Family Translocation Renal Cell Carcinomas

BACKGROUND

MiT family translocation renal cell carcinoma (TRCC) is a rare and aggressive subgroup of renal cell carcinoma harboring high expression of c-MET. While TRCC response rates to VEGF receptor tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors are limited, efficacy of cabozantinib (a VEGFR, MET, and AXL inhibitor) in this subgroup is unclear.

METHODS

We performed a multicenter, retrospective, international cohort study of patients with TRCC treated with cabozantinib. The main objectives were to estimate response rate according to RECIST 1.1 and to analyze progression-free survival (PFS) and overall survival (OS).

RESULTS

Fifty-two patients with metastatic TRCC treated in the participating centers and evaluable for response were included. Median age at metastatic diagnosis was 40 years (IQR 28.5-53). Patients' IMDC risk groups at diagnosis were favorable (9/52), intermediate (35/52), and poor (8/52). Eleven (21.2%) patients received cabozantinib as frontline therapy, 15 (28.8%) at second line, and 26 (50%) at third line and beyond. The proportion of patients who achieved an objective response was 17.3%, including 2 complete responses and 7 partial responses. For 26 (50%) patients, stable disease was the best response. With a median follow-up of 25.1 months (IQR 12.6-39), median PFS was 6.8 months (95%CI 4.6-16.3) and median OS was 18.3 months (95%CI 17.0-30.6). No difference of response was identified according to fusion transcript features.

CONCLUSION

This real-world study provides evidence of the activity of cabozantinib in TRCC, with more durable responses than those observed historically with other VEGFR-TKIs or ICIs.

An interdisciplinary consensus on the management of brain metastases in patients with renal cell carcinoma

Brain metastases are a challenging manifestation of renal cell carcinoma. We have a limited understanding of brain metastasis tumor and immune biology, drivers of resistance to systemic treatment, and their overall poor prognosis. Current data support a multimodal treatment strategy with radiation treatment and/or surgery. Nonetheless, the optimal approach for the management of brain metastases from renal cell carcinoma remains unclear. To improve patient care, the authors sought to standardize practical management strategies. They performed an unstructured literature review and elaborated on the current management strategies through an international group of experts from different disciplines assembled via the network of the International Kidney Cancer Coalition. Experts from different disciplines were administered a survey to answer questions related to current challenges and unmet patient needs. On the basis of the integrated approach of literature review and survey study results, the authors built algorithms for the management of single and multiple brain metastases in patients with renal cell carcinoma. The literature review, consensus statements, and algorithms presented in this report can serve as a framework guiding treatment decisions for patients. CA Cancer J Clin. 2022;72:454-489.

Current Systemic Treatments for the Hereditary Cancer Syndromes: Drug Development in Light of Genomic Defects

Advances in the genetic basis of different tumors have led to identification of tumor vulnerabilities that can be turn into targeted therapies. In this regard, PARP inhibitors cause synthetic lethality with tumors harboring BRCA1 or BRCA2 genetic alterations. On the other hand, tumors with microsatellite instability, either due to germline or sporadic alterations, are candidates for immune checkpoint inhibitors. Finally, patients with von Hippel-Lindau disease who carry a germline alteration in the VHL gene may benefit form belzutifan, a hypoxia-inducible factor 2 alpha inhibitor. Overall, research on the underlying pathological mechanisms of these tumors has provided new therapeutic opportunities that might be expanded to other sporadic tumors with similar biology.

Perioperative nivolumab monotherapy versus nivolumab plus ipilimumab in resectable hepatocellular carcinoma: a randomised, open-label, phase 2 trial

BACKGROUND

Hepatocellular carcinoma has high recurrence rates after surgery; however, there are no approved standard-of-care neoadjuvant or adjuvant therapies. Immunotherapy has been shown to improve survival in advanced hepatocellular carcinoma; we therefore aimed to evaluate the safety and tolerability of perioperative immunotherapy in resectable hepatocellular carcinoma.

METHODS

In this single-centre, randomised, open-label, phase 2 trial, patients with resectable hepatocellular carcinoma were randomly assigned (1:1) to receive 240 mg of nivolumab intravenously every 2 weeks (for up to three doses before surgery at 6 weeks) followed in the adjuvant phase by 480 mg of nivolumab intravenously every 4 weeks for 2 years, or 240 mg of nivolumab intravenously every 2 weeks (for up to three doses before surgery) plus one dose of 1 mg/kg of ipilimumab intravenously concurrently with the first preoperative dose of nivolumab, followed in the adjuvant phase by 480 mg of nivolumab intravenously every 4 weeks for up to 2 years plus 1 mg/kg of ipilimumab intravenously every 6 weeks for up to four cycles. Patients were randomly assigned to the treatment groups by use of block randomisation with a random block size. The primary endpoint was the safety and tolerability of nivolumab with or without ipilimumab. Secondary endpoints were the proportion of patients with an overall response, time to progression, and progression-free survival. This trial is registered with ClinicalTrials.gov (NCT03222076) and is completed.

FINDINGS

Between Oct 30, 2017, and Dec 3, 2019, 30 patients were enrolled and 27 were randomly assigned: 13 to nivolumab and 14 to nivolumab plus ipilimumab. Grade 3-4 adverse events were higher with nivolumab plus ipilimumab (six [43%] of 14 patients) than with nivolumab alone (three [23%] of 13). The most common treatment-related adverse events of any grade were increased alanine aminotransferase (three [23%] of 13 patients on nivolumab vs seven [50%] of 14 patients on nivolumab plus ipilimumab) and increased aspartate aminotransferase (three [23%] vs seven [50%]). No patients in either group had their surgery delayed due to grade 3 or worse adverse events. Seven of 27 patients had surgical cancellations, but none was due to treatment-related adverse events. Estimated median progression-free survival was 9·4 months (95% CI 1·47-not estimable [NE]) with nivolumab and 19·53 months (2·33-NE) with nivolumab plus ipilimumab (hazard ratio [HR] 0·99, 95% CI 0·31-2·54); median time to progression was 9·4 months (95% CI 1·47-NE) in the nivolumab group and 19·53 months (2·33-NE) in the nivolumab plus ipilimumab group (HR 0·89, 95% CI 0·31-2·54). In an exploratory analysis, three (23%) of 13 patients had an overall response with nivolumab monotherapy, versus none with nivolumab plus ipilimumab. Three (33%) of nine patients had a major pathological response (ie, ≥70% necrosis in the resected tumour area) with nivolumab monotherapy compared with three (27%) of 11 with nivolumab plus ipilimumab.

INTERPRETATION

Perioperative nivolumab alone and nivolumab plus ipilimumab appears to be safe and feasible in patients with resectable hepatocellular carcinoma. Our findings support further studies of immunotherapy in the perioperative setting in hepatocellular carcinoma.

FUNDING

Bristol Myers Squibb and the US National Institutes of Health.

Immuno-oncology (IO) combinations +/- VEGF targeted therapy (VEGF TT) in patients (pts) with advanced mit family translocation renal cell carcinomas (tRCC): Results from an international multicenter study

343

Background: IO combinations are standard of care for first-line therapy of clear-cell RCC; however, non-clear cell histologies including tRCC were not included in the registrational trials. We previously reported a modest efficacy (objective response rate [ORR] <20%) with IO monotherapy (PD-1 blockade) in tRCC (Boilève et al, JITC. 2018). The efficacy of IO combinations +/- VEGF TT has not been reported. Methods: This is a retrospective, international, multicenter study of pts with tRCC treated with IO-IO or IO+VEGF TT at 11 centers in the US, France, and Belgium. Only pts with confirmed TFE3 or TFEB translocation by fluorescent-in-situ hybridization (FISH) were included. ORR and progression-free survival (PFS) were assessed by RECIST. Overall survival (OS) was assessed by Kaplan-Meier methods. OS was measured from initiation of therapy till death or last follow up. We also assessed the association between OS and baseline prognostic variables. Results: 29 patients with metastatic tRCC were included in this analysis. Median age at starting therapy was 38 (IQR 27, 53) years. Female:Male ratio was 0.9:1. FISH revealed a translocation involving TFE3 and TFEB in 22 and 7 patients, respectively. Most frequent metastatic sites at diagnosis were lungs (76%), liver (52%), retroperitoneal adenopathy (48%), and bone (38%). IMDC risk at diagnosis was favorable (31%), intermediate (45%) and poor (24%). Combinations of IO+VEGF TT and anti-PD1 (L1) + anti-CTLA-4 (IO+IO) were used in 11 and 18 pts, respectively. 17 (59%) pts received IO combinations as 1L, 7 (24%) pts as 2L and 5 (17%) pts as ≥3L. ORR in the IO+IO group was 1/18 (5.5%), while in IO+VEGF TT group was 4/11 (36%). For 20 (69%) pts, progressive disease was the best overall response. At a median follow-up of 12.9 months (mo), median PFS was 3.2 mo and median OS was 13.5 mo for all 29 pts (Table). Median PFS in the IO+IO group was 2.8 mo, and 5.4 mo in IO+VEGF TT group (HR=0.81, 95% CI: 0.35-1.84). Conclusions: In this small retrospective study of tRCC, IO+IO therapy produced modest activity based on low ORR and short PFS while IO+VEGF TT produced numerically higher ORR and longer PFS. Insights into the biological basis of tRCC are necessary to develop more effective therapies for this rare and aggressive RCC variant.[Table: see text]

Safety and differential clinical activity of nivolumab plus ipilimumab (nivo-ipi) in patients (pts) with non-clear cell renal cell carcinoma (nccRCC)

356

Background: Pembrolizumab monotherapy recently showed promising efficacy in nccRCC. The objective response rate (ORR) by histology was 28.8% for papillary, 9.5% for chromophobe, and 30.8% for unclassified RCC (McDermott, JCO 2021). However, combination immunotherapy data are limited in nccRCC. Methods: We retrospectively evaluated the efficacy and safety of nivo-ipi in pts with nccRCC treated at our institution. ORR and progression-free survival (PFS) were determined using RECIST. Overall survival (OS) was measured from therapy start to death or last follow up. Results: Between November 2017 and July 2020, 27 pts with nccRCC were treated with nivo-ipi at our institution; 25 pts (93%) received nivo-ipi as first-line therapy and 14 pts (52%) had prior nephrectomy. Histology subtypes included 13 (48%) papillary (4 with sarcomatoid features [SF]), 7 (26%) chromophobe (4 with SF), and 7 (26%) unclassified. Sites of metastases included lung in 52%, bone in 37%, and liver in 22% of pts. IMDC risk was favorable (8%), intermediate (48%) and poor (44%). ORR in all pts was 30%; 7 pts achieved a partial response (PR), and 1 patient achieved a complete response (CR). ORR by histology subtype was 54% for papillary, 14% for chromophobe, and 0% for unclassified (table). Clinical benefit (defined as PR, CR, or stable disease [SD] for > 6 months) was achieved in 62% for papillary, 57% for chromophobe, and 29% for unclassified. At a median follow-up time of 17.1 months, for all 27 pts, median PFS was 7.2 months, and median OS was 18.5 months. Median OS per each variant histology subtype was not reached in papillary, 25.7 months in chromophobe, and 7.4 months in unclassified. Median PFS per variant histology subtype was 11.8 months in papillary, 4.0 months in chromophobe, and 2.8 months in unclassified. Seven pts (26%) developed Grade ≥3 toxicity: pneumonitis (2), colitis (2), hepatitis (1), rash (1), and immune-mediated glomerulonephritis (1). Conclusions: In this small retrospective study, nivo-ipi was well-tolerated in pts with nccRCC and yielded high ORR and prolonged PFS in papillary RCC but disappointing efficacy results in chromophobe and unclassified RCC. Molecular studies are ongoing to understand the mechanisms of response and resistance to nivo-ipi in these tumor subtypes.[Table: see text]

Serum IGF-1 Scores and Clinical Outcomes in the Phase III IMbrave150 Study of Atezolizumab Plus Bevacizumab versus Sorafenib in Patients with Unresectable Hepatocellular Carcinoma

PURPOSE

Child-Turcotte-Pugh class A (CTP-A) in unresectable hepatocellular carcinoma (HCC) is the standard criterion for active therapy and clinical trial enrollment. We hypothesized that insulin-like growth factor-1 (IGF-1) derived scores may provide improved survival prediction over CTP classification. This study aimed to evaluate the potential prognostic and predictive effects of IGF-1 derived scores in the phase III IMbrave150 study.

PATIENTS AND METHODS

Baseline and on-treatment serum IGF-1 levels from 371 patients were subjected to central analysis. Patients' IGF-1 score (1/2/3) and IGF-CTP score (A/B/C) were determined based on pre-specified cutoffs. Outcomes were analyzed by baseline and by on-treatment changes of the IGF-1 and IGF-CTP scores within and between the two treatment arms. The interaction between these scores and outcomes was assessed using univariate and multivariate analyses.

RESULTS

Baseline IGF-CTP score (A vs B/C) showed prognostic significance for OS in both the atezolizumab-bevacizumab (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.20-0.56; P<0.001) and sorafenib (HR, 0.32; 95% CI, 0.16-0.65; P=0.002) arms. Baseline IGF-1 score (1 vs 2/3) also showed prognostic significance for OS in both the atezolizumab-bevacizumab (HR, 0.33; 95% CI, 0.20-0.55; P<0.001) and sorafenib (HR, 0.48; 95% CI, 0.26-0.89; P=0.02) arms. HRs for PFS were consistent with those for OS. No significant predictive effects were observed for either score between the two arms. Kinetic analysis revealed that patients with increased IGF-1 score (1-> 2/3) at 3 weeks post treatment had shorter OS than patients with stable IGF-1 score of 1 in both the atezolizumab-bevacizumab (HR, 3.70; 95% CI, 1.56-8.77; P=0.003) and sorafenib (HR, 5.83; 95% CI, 1.88-18.12; P=0.0023) arms.

CONCLUSION

Baseline and kinetic change of IGF-CTP and IGF-1 scores are independent prognostic factors for patients with unresectable HCC treated with atezolizumab-bevacizumab or sorafenib. These novel scores may provide improved patient stratification in future HCC clinical trials. IMbrave150 ClincialTrials.gov number, NCT03434379.

42 The role of tissue stiffness in predicting the immunotherapy response in hepatocellular carcinoma

Background

Currently, there is no standard biomarker that predict immunotherapy response in hepatocellular carcinoma (HCC). Here, we aim to investigate the role of tissue stiffness measured by magnetic resonance elastography (MRE) in predicting neoadjuvant immunotherapy response in patients with resectable HCC.

Methods

This was a study of 15 patients with HCC treated with immune checkpoint blockade (ICB) therapy, nivolumab ± ipilimumab, followed by surgical resection. HCC MRE assessment was performed at baseline and after 6 weeks of therapy. HCC stiffness (kPa) was measured on MRE elastograms (liver stiffness maps). Baseline stiffness and changes in stiffness were compared with treatment response to ICB. Treatment response was defined as a tumor with more than 60% necrosis which was the major pathological response. Analysis was performed using descriptive statistics, Fisher’s exact test, and Wilcoxon rank sum test; p-value <0.05 was considered statistically significant.

Results

Fifteen patients were evaluable for MRE assessment. The median age was 67 years. Etiology of liver disease was NASH (n=4), HCV (n=3), HBV (n=2) and unknown (n=6). Three out of 15 patients (20%) achieved a major pathological response (MPR). Median baseline HCC stiffness and change in stiffness were 4.6 kPa and –0.2 kPa, respectively. Among the 4 patients with stiffness increase, 3 (75%) of them achieved MPR and 1 (25%) did not achieve MPR. Among the patients without stiffness increase, none of them achieved MPR. Fisher’s exact test indicates that increase in stiffness was associated with a higher chance to achieve MPR than patients without stiffness increase (p=0.0088). Median baseline HCC stiffness for responders and non-responders was 6.8 (5.4, 9) kPa and 3.9 (2.2, 9.7) kPa, respectively (p=0.09). The median change in HCC stiffness for responders and non-responders was 1 (1, 1.4) kPa and -0.4 (-2.2, 0.7) kPa, respectively (p=0.02).

Conclusions

Patients who achieved MPR inclined to have a higher baseline stiffness than patients who did not achieve MPR. Regarding the changes in stiffness between the two arms, patients with MPR group had a greater increase than that in the non-MPR group. In conclusion, baseline and change in MRE stiffness may be a useful biomarkers in predicting response to ICB therapy in HCC.

Ethics Approval

This was an Institutional Review Board approved study (MDACC 2017–0972). All patients provided written informed consent.

241 Immune checkpoint blockade (ICB) in brain metastases (BM) from advanced small cell urothelial cancer (aSCUC)

Background

The risk of BMs in patients with aSCUC, having bulky tumors or non-cerebral metastasis at presentation, is high. We aimed to investigate the impact of ICB on the clinical outcomes of patients with aSCUC and BMs.

Methods

Patients with aSCUC treated at MD Anderson Cancer Center between April 1992 and July 2019 were included if they had brain imaging and developed BMs during their disease course. Median overall survival (mOS) was calculated from diagnosis of BMs until death and if alive was censored at last contact. Hazard ratios (HR) and 95% confidence intervals (95% CI) were calculated using logrank test.

Results

Among 216 patients with aSCUC, 111 underwent computed tomography or magnetic resonance imaging of the brain, and 34 (31%) were diagnosed with BMs. Baseline characteristics are included (table 1). At initial diagnosis of SCUC, clinical stage was cT1/x,cT2,≥cT3/4 or N+ (15%,44%,41%, respectively). Twenty-three (67.6%) underwent prior cystectomy, 16 (47%) had received neoadjuvant chemotherapy (NACT). Pathologic response at cystectomy after NACT was pT0/Tis,pT1,pT2,≥pT3b/4 or N+ (31%,6%,13%,50%, respectively). Those who did not undergo cystectomy (11, 32%) were either due to progression, declining surgery, or had de novo metastatic disease (27%,18%,55%, respectively). Regarding localized BM management, 9 (26%) patients received whole brain radiation therapy, 7 (21%) received stereotactic radiosurgery (SRS) and 7 (21%) received both. Median follow-up from BM diagnosis was 31.7 months. Five patients elected to pursue comfort care only, with mOS 0.7 months. Twenty-three patients received systemic therapy, including 11 (48%) who received ICB during any line of therapy. Majority of patients received ICB as single agent anti-PD(L)1; one patient received a doublet of anti-PD1+anti-CTLA4. Patients who were treated with ICB had numerically longer mOS as compared to those who solely received chemotherapy (10.7 months vs. 9.0 months, HR=0.47,95%CI=0.18–1.25,P=0.15), (figure 1). mOS decreased in patients with 1 vs 2 vs 3 vs ≥5 BMs (18.8,8.7,7.5 and 4.7 months, respectively, P=0.02), (figure 2). Furthermore, mOS improved with combination of ICB+SRS vs chemotherapy+SRS vs ICB without SRS vs chemotherapy without SRS (unreached,20.9,7.5,8.4, respectively, P=0.03) (figure 3).

Abstract 241 Table 1

Baseline characteristics of patients

Abstract 241 Figure 1

Survival based on systemic therapy approach among all SCUC patients with brain metastases (n=34)

Abstract 241 Figure 2

Survival based on number of brain metastases among all 34 patients

Abstract 241 Figure 3

Survival based on systemic + local therapy approach among SCUC patients with brain metastases with brain metastases who received both (n=23)

Conclusions

In this first analysis to describe outcomes of patients with aSCUC and BMs with the inclusion of ICB treatment and despite the small sample size, we see a trend toward increased survival with fewer BMs, especially with combined ICB and SRS. Although challenging due to its rarity, future prospective trials evaluating the synergy between ICB and SRS in SCUC should be considered.

Ethics Approval

This retrospective study received approval from the MD Anderson Cancer Center institutional review board

Current Landscape and Future Directions of Biomarkers for Immunotherapy in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common liver cancer and one of the leading causes of cancer-related deaths in the world. Multiple immunotherapeutic approaches have been investigated to date, and immunotherapy has become the new standard of care therapy in HCC. However, the current role of immunotherapy in HCC remains non-curative. Given this context, a high priority for oncology is understanding the biomarkers that predict clinical response to immunotherapy, have the potential to improve patient selection to maximize the clinical benefit, and spare unnecessary toxicity. In this review, we summarize the key predictive and prognostic biomarkers investigated in immunotherapy clinical trials in HCC and the emerging biomarkers to serve as a roadmap for future clinical trials. Biomarkers from tumoral tissues including PDL-1 expression, tissue infiltrating lymphocytes, tumor mutational burden (TMB) and specific immune signatures, and from peripheral blood including neutrophil-to-lymphocytes ratio, platelet-to-lymphocytes ratio, circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and specific cytokines, along with gut microbiota are among the studied biomarkers to date in the HCC era. More integrative approaches, including mathematical biomarkers to predict immunotherapy outcomes, are yet to be studied in HCC.

MK-6482 as a potential treatment for von Hippel-Lindau disease-associated clear cell renal cell carcinoma

INTRODUCTION

Von Hippel-Lindau (VHL) disease is an inherited autosomal dominant syndrome caused by a germline mutation and/or deletion of the VHL gene. Inappropriate hypoxia-inducible factor (HIF)-mediated transcription of proangiogenic and metabolic genes leads to the development of tumors and cysts in multiple organs. Surgery is a standard treatment for localized tumors with a risk of metastasis or organ dysfunction. Repeated surgeries cause substantial morbidity and have a major impact on quality of life. There is an urgent need to develop effective and safe systemic treatments for VHL disease manifestations. The small-molecule HIF 2 alpha inhibitor MK-6482 (belzutifan) has demonstrated significant efficacy in VHL disease related renal cell carcinomas, hemangioblastomas, and pancreatic neuroendocrine tumors while demonstrating an acceptable safety profile.

AREAS COVERED

This paper reviews the development of the HIF-2 alpha inhibitor, MK-6482, and discusses preliminary results of ongoing phase I/II studies in renal cell carcinoma (RCC) and VHL disease. An examination of ongoing clinical development of MK-6482 and perspectives on potential future developments and challenges are offered.

EXPERT OPINION

Because of its favorable safety profile, its clear efficacy in VHL disease, promising findings in sporadic, advanced RCC, and convenient oral formulation, MK-6482 is expected to become a leading treatment for VHL disease. Among other currently available oral agents, we believe that MK-6482 will be a preferred treatment for VHL-associated RCC.

Outcomes of patients with intermediate-risk or poor-risk metastatic renal cell carcinoma who received their first cycle of nivolumab and ipilimumab in the hospital because of symptomatic disease: The MD Anderson Cancer Center experience

Nivolumab plus ipilimumab (nivo/ipi) is an approved therapy for patients with intermediate-risk or poor-risk metastatic renal cell carcinoma (mRCC). Clinical factors that guide the selection of this regimen for patients with mRCC are urgently needed. We retrospectively analyzed medical records of patients with mRCC who were hospitalized at MD Anderson Cancer Center because of cancer-related symptoms and received their first cycle of nivo/ipi in the inpatient setting. Clinical parameters, including demographics, histology, clinical history, response, and survival, were collected. The 4-month survival probability, progression-free survival (PFS), and overall survival (OS) were calculated using Kaplan-Meier methods. Between November 2017 and 21 June 2020 patients were identified that fit the search: 19 patients (91%) had poor-risk disease based on the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk score; 17 patients (81%) had ≥4 risk factors; and 9 patients (43%) had sarcomatoid features on histology. Shortness of breath (28%) and abdominal pain (19%) were the two most common reasons for hospitalization. Partial response was achieved in 14% (3/21) of patients. Median PFS for all patients was 1.7 months (95% CI 0-3.9); median OS for all patients was 1.7 months (95% CI 0-4.2); and the 4-month survival probability was 36% (95% CI 25%-47%). In this retrospective study, patients with intermediate-risk or poor-risk mRCC who are hospitalized at a large tertiary referral center for cancer-related symptoms derive limited clinical benefit from nivo/ipi when started in the inpatient setting. Alternative, more effective systemic therapies should be considered for these patients.

Outcomes of changing systemic therapy in patients with relapsed breast cancer and 1 to 3 brain metastases

The development of brain metastases (BMs) in breast cancer (BC) patients remains a challenging complication. Current clinical practice guidelines recommend local treatment of BMs without changing systemic therapy (CST) in patients with stable extracranial disease. We retrospectively investigated the impact of CST (when applicable as per treating physician's discretion) following the diagnosis and management of oligometastatic (1-3) BMs in patients without extracranial metastases on the progression-free survival time (PFS), and overall survival (OS). Hazard ratios (HRs) were calculated using the Cox proportional hazard model. Among the 2645 patients with BC and BMs treated between 2002 and 2015, 74 were included for analysis. 40.5% of patients had HER2 + disease. Median time from diagnosis of BC to BMs was 17.6 months. 54%, 8%, and 38% of BMs were managed by radiation, craniotomy, or combination, respectively. Following the primary management of BMs, we observed that CST occurred in 26 (35.5%) patients, consisting of initiation of therapy in 13.5% and switching of ongoing adjuvant therapy in 22%. Median PFS was 6.6 months among patients who had CST compared to 7.1 months in those who did not (HR = 0.88 [0.52-1.47], p = 0.62). Median OS was 20.1 months among patients who had CST compared to 15.1 months in those who did not (HR = 0.68 [0.40-1.16], p = 0.16). Upon the successful local management of oligometastatic BMs in patients without extracranial disease, we did not find a significant difference in survival between patients who experienced a change in systemic therapy as compared to those who did not.

Efficacy of cabozantinib in advanced MiT family translocation renal cell carcinomas (TRCC)

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Background: MiT family translocation renal cell carcinomas (TRCC) represent a rare and aggressive subgroup of RCC harboring high expression of c-MET. While response rates of VEGF receptor-tyrosine kinase inhibitor and immune checkpoint inhibitors are limited, efficacy of cabozantinib (a TKI that inhibits VEGFR, MET, and AXL) in this subgroup is unclear. Methods: We performed a multicentre, retrospective, international cohort study of patients with TRCC treated with cabozantinib regardless the line of treatment at 7 centers (3 in France and 4 in the US). The main objectives were to estimate response rate according to RECIST criteria, and to analyze progression-free survival (PFS) and overall survival (OS). Results: Among 31 metastatic patients treated in the participating centers, 24 were evaluable for response and were included in this study (21 with TFE3 and 3 with TFEB translocations). Median age at diagnosis was 43.5 years (range, 22–70). Most frequent metastatic sites at diagnosis were lungs (62.5%), retroperitoneal lymph nodes (45.8%) and bone (37.5%). Patient’s IMDC risk group at diagnosis was favourable (20,8%), intermediate (62,5%) and poor (16,7%). Seven (29%) patients received cabozantinib at first line, 9 (37.5%) at second line and 8 (33%) at third line and beyond. The proportion of patients who achieved an objective response was 16.6%, including 1 complete response and 3 partial responses. For 11 (45.8%) patients, stable disease was the best response. With a median follow-up of 14 months (IQR 5-23), median PFS was 8.4 months (range, 1-34+) and median OS was 17 months (range, 2-43). No PFS difference was detected overall or in any subgroup except in patients with bone metastasis which harbored a median PFS of 3.6 months as compared to 9.1 months for those without (p=0.03). Conclusions: This real-world study provides evidence supporting activity of cabozantinib in TRCC, with more durable responses to therapy than those observed with of VEGF receptor-tyrosine kinase inhibitor and immune checkpoint inhibitors. International collaborations and prospective studies are necessary to identifies efficacious therapies for this rare disease that lacks evidence-based treatment options.

Analysis of chemotherapy-related modulation of the immune microenvironment in muscle invasive bladder cancer

5049

Background: Novel immune checkpoint inhibitors provide significant clinical benefits for patients with metastatic bladder cancer. It is known that chemotherapy administered to muscle invasive patients prior to radical cystectomy (neoadjuvant chemotherapy) improves survival. However, it is unknown whether immune checkpoint inhibitor therapy in combination with chemotherapy can provide further clinical benefits as neoadjuvant therapy. Here, we test the hypothesis that treatment of bladder cancer with certain chemotherapy agents can modulate bladder tumor immune microenvironment (TIME) for optimal combination with immune checkpoint therapy. Methods: Time course and dose response experiments were performed using eight human bladder cancer cell lines (UMUC3, RT4, 253J, RT112, J82, HT1376, T24, and HT1197) and two murine bladder cancer cell lines (MB49, MBT2). Conventional chemotherapy agents and combinations (MVAC, GemCis, PemVin) were used to treat bladder cancer cell lines. Flow cytometry analysis was used to measure immune cell subsets and PD-L1 expression. For in vivo studies, the subcutaneous MB49 murine bladder cancer model was used to evaluate responses to chemotherapy and anti-PD-L1 combinations. Pre- and post-treatment bladder tumors from patients who received neoadjuvant MVAC and GemCis are selected to evaluate changes in TIME. Results: Our data demonstrate that chemotherapy agents varies in their ability to up-regulate PD-L1 expression on bladder cancer cell lines. Vinblastine, gemcitabine, and pemetrexed treatment each resulted in significant upregulation of PD-L1 expression. Combination regimens with GemCis or PemVin demonstrated induction of PD-L1 across different cell lines. In in-vivo studies, GemCis + anti-PD-L1 had a synergistic activity in causing tumor regression. We also found that sequential versus concurrent treatment with chemotherapy and anti-PD-L1 had a similar outcome. Tissue analyses show that combination chemotherapies increased CD4 Th cell infiltration while decreasing Treg cells in TIME. Consistent with the in vitro data, PD-L1 expression was also up-regulated with combination treatment. The evaluation of TIME modulation in human bladder tumors treated with neoadjuvant MVAC or GemCis is ongoing. Conclusions: Our data suggest that chemotherapy could favorably modulate TIME and thus, may be combined with immune checkpoint inhibitor to improve anti-tumor responses in the neoadjuvant setting for patients with muscle invasive bladder cancer.

Evaluation of brain metastasis in JAVELIN Renal 101: Efficacy of avelumab + axitinib (A+Ax) versus sunitinib (S)

687

Background: Patients (pts) with brain metastasis from renal cell carcinoma (RCC) have poor prognosis and are often excluded from randomized registrational trials. The phase 3 JAVELIN Renal 101 trial (NCT02684006) demonstrated significantly improved progression-free survival (PFS) for A+Ax vs S in pts with advanced RCC (Motzer NEJM 2019). The activity of A+Ax in pts with brain metastasis enrolled in JAVELIN Renal 101 is presented. Methods: PFS was compared between treatment arms for the subgroup of pts randomized in JAVELIN Renal 101 with brain metastases at enrollment (pts with brain disease site prior to randomization by blinded independent central review [BICR] or by investigator assessment). PFS time was summarized per BICR assessment by treatment arm using the Kaplan-Meier method. The Cox proportional hazards model was fitted to compute the hazard ratio (HR) and the corresponding CI. In addition, time to brain metastasis was assessed for pts without brain metastasis by BICR at enrollment after treating death as a competing risk. Results: Of all randomized pts (A+Ax arm, N=442; S, N=444), 23 in each arm (5.2%) had asymptomatic brain metastasis at enrollment; of these, pts assigned to A+Ax had a PFS of 4.9 mo (95% CI: 1.6, 5.7) vs 2.8 mo (95% CI: 2.3, 5.6) for pts assigned to S (HR: 0.90; 95% CI: 0.43, 1.88). Among pts without brain metastasis at enrollment, 8 pts on the A+Ax arm and 10 on the S arm developed brain metastasis during the trial, based on BICR assessment; 17/18 occurred ≤12 mo from randomization. The cumulative incidence rate of brain metastasis at 18 mo was 2% (95% CI: 0.6, 3.3) for the A+Ax arm and 3% (95% CI: 1.1, 4.8) for the S arm. Conclusions: In this post hoc exploratory analysis of JAVELIN Renal 101, the observed PFS among pts with brain metastasis at enrollment was similar between the two arms, with HR and median PFS numerically favoring A+Ax. Pts on the S arm had a numerically higher incidence of new brain metastases on trial. Outcomes are poor in pts with advanced RCC and brain metastasis; more effective treatments are needed. Clinical trial information: NCT02684006.

Phase II Study of Carfilzomib in Patients With Refractory Renal Cell Carcinoma

BACKGROUND

A von Hippel Lindau (VHL) mutation or functional inactivation occurs in the a large proportion of patients with clear-cell renal cell carcinoma (ccRCC), which results in the dysregulation of a number of key cellular functions. A high throughput screen and candidate compound assessment revealed that agents with proteasome inhibition properties were able to stabilize point-mutated VHL and restore some of its functions.

PATIENTS AND METHODS

Nine patients with histologically confirmed metastatic ccRCC with disease progression during at least 1 previous systemic therapy were treated with carfilzomib at a dose of 20 mg/m² over 30 minutes via intravenous (I.V.) infusion on days 1 and 2 and a dose of 56 mg/m² over 30 minutes via I.V. infusion on days 8, 9, 15, and 16 of each 4-week cycle.

RESULTS

The study was stopped after 9 patients were enrolled because of futility. Of the 9 patients treated in the study, all patients had disease progression within 4 months, with a median time of 1.8 months (95% confidence interval, 0.8-3.6 months). No patient showed a response according to Response Evaluation Criteria In Solid Tumors. Three patients showed a best response of stable disease. The most common side effects were musculoskeletal pain, elevated creatinine level, anemia, hyperkalemia, leukopenia, lymphopenia, and fatigue.

CONCLUSION

Although the negative safety and efficacy results of this study do not favor the use of carfilzomib for the treatment of ccRCC, previous studies have shown selected patients achieved partial or complete response to this class of agent. Further preclinical investigations to evaluate the molecular characteristics of the patients who respond to proteasome inhibitors will better characterize the underlying mechanism of response, and might allow for the selection of an appropriate patient population in future studies.

Hypoxia signaling and immune infiltration in a presurgical trial of sunitinib in patients with clear cell renal cell carcinoma (RCC)

e16115

Background: Presurgical clinical trial design allow for pharmacodynamically relevant tissue collection that can inform regarding drivers of tumor biology. An unmet need is the ability to identify tumors that may respond to immunotherapy and the underlying mechanism of immune infiltration. Methods: This single arm phase II study was designed to test efficacy and safety of presurgical sunitinib treatment in metastatic RCC, and to identify drivers of tumor biology. Patients (pts) with metastatic RCC and a resectable primary received sunitinib 50mg PO daily for four weeks, and underwent restaging. If deemed a candidate, pts underwent cytoreductive nephrectomy (CN) during their second cycle of sunitinib, with last dose administered the day before surgery. Pts were restaged postoperatively and continued on sunitinib if no progressive disease was seen. Genomic and histological characteristics of RCC were evaluated for correlations between response and biological features. Results: Between June 2008 and October 2011, 50 pts were enrolled. 41 underwent CN. Seven pts showed refractory disease and were not considered surgical candidates. No sunitinib related perioperative toxicities were observed. Six pts progressed on first postoperative imaging studies, with three patients developing new brain metastases. Median progression free survival (PFS) was 8.6 months, and overall survival was 38 months. Objective response rate was 30 percent with 2 pts demonstrating a complete response. Analysis on 39 pts showed HIF1a staining was significantly associated with PFS (p = 0.023*, univariate Cox model), with a hazard ratio (HR) of 1.028 (95% CI, 1.004-1.053). This association remained significant in a multivariate Cox model adjusting for age and gender (p = 0.019*). In addition, HIF1a correlated with multiple immune markers (CD8, CD45RO, PD1, Treg, CD68, and LAG3). Analysis of genomic correlates is ongoing. Conclusions: Presurgical sunitinib therapy in RCC is safe and efficacious. HIF1a staining is associated with shorter PFS, and with increased immune infiltration. Tissue HIF1a should be explored as a marker, and studied mechanistically as a driver of the immune microenvironment in RCC. Clinical trial information: NCT00715442.

Phase II Study of Two Weeks on, One Week off Sunitinib Scheduling in Patients With Metastatic Renal Cell Carcinoma

Purpose Standard frontline treatment of patients with metastatic renal cell carcinoma currently includes sunitinib. A barrier to long-term treatment with sunitinib includes the development of significant adverse effects, including diarrhea, hand-foot syndrome (HFS), and fatigue. This trial assessed the effect of an alternate 2 weeks on, 1 week off (2/1) schedule of sunitinib on toxicity and efficacy in previously untreated patients with metastatic renal cell carcinoma. Methods Patients started with oral administration of 50 mg sunitinib on a 2/1 schedule and underwent schedule and dose alterations if toxicity developed. The primary end point was < 15% grade ≥ 3 fatigue, diarrhea, or HFS. With 60 patients, the upper bound of the CI would fall below the published 4/2 schedule grade ≥ 3 toxicity rate of 25% to 30%. Results Fifty-nine patients were treated between August 2014 and March 2016. Seventy-seven percent were intermediate or poor risk per Memorial Sloan Kettering Cancer Center criteria. With a median follow-up of 17 months, 25% of patients experienced grade 3 fatigue, HFS, or diarrhea; 37% required a dose reduction, and 10% discontinued because of toxicity. The overall response rate was 57%, median progression-free survival was 13.7 months, and median overall survival was not reached. At 12 weeks, Functional Assessment of Cancer Therapy-General scores dropped between 0% and 10% from baseline, with less reduction in patients who continued treatment longer. Conclusion The primary end point of decreased grade 3 toxicity was not met; however, treatment with a 2/1 sunitinib schedule is associated with a lack of grade 4 toxicity, a low patient discontinuation rate, and high efficacy.

Effects of tamoxifen on urinary incontinence: Case report and review of literature

RATIONALE

Tamoxifen has been used in women with hormone receptor-positive breast cancer and has been shown to successfully reduce both recurrence and mortality. On the contrary, long-term use of tamoxifen has hormone-related urogenital side effects which decrease the quality of life of the patients.

PATIENT CONCERNS

In this case report, we present a breast cancer patient receiving tamoxifen who developed urinary incontinence; we discuss the effects of tamoxifen on urinary incontinence, which decreases quality of life of the patients who were evaluated in our clinic.

DIAGNOSES

Breast cancer, urinary incontinence.

INTERVENTIONS

Temporarily discontinuing tamoxifen.

OUTCOMES

Urinary incontinence resolved.

LESSONS

Based on the case we reported and literature, estrogen can cause a dose-dependent increase in incontinence, but more preclinical and clinical studies of both estrogen and SERMs are needed to support this notion; given the fact that some small-scale clinical studies have not proven a direct relationship between tamoxifen and urinary incontinence. We suggest that clinicians faced with the issue should temporarily stop usage of the drug once the complaint of urinary incontinence arises.

A randomized phase 2 study of MK-2206 versus everolimus in refractory renal cell carcinoma

Background

Activation of the phosphoinisitide-3 kinase (PI3K) pathway through mutation and constitutive upregulation has been described in renal cell carcinoma (RCC), making it an attractive target for therapeutic intervention. We performed a randomized phase II study in vascular endothelial growth factor (VEGF) therapy refractory patients to determine whether MK-2206, an allosteric inhibitor of AKT, was more efficacious than the mammalian target of rapamycin inhibitor everolimus.

Patients and methods

A total of 43 patients were randomized in a 2:1 distribution, with 29 patients assigned to the MK-2206 arm and 14 to the everolimus arm. Progression-free survival (PFS) was the primary endpoint.

Results

The trial was closed at the first futility analysis with an observed PFS of 3.68 months in the MK-2206 arm and 5.98 months in the everolimus arm. Dichotomous response rate profiles were seen in the MK-2206 arm with one complete response and three partial responses in the MK-2206 arm versus none in the everolimus arm. On the other hand, progressive disease was best response in 44.8% of MK2206 versus 14.3% of everolimus-treated patients. MK-2206 induced significantly more rash and pruritis than everolimus, and dose reduction occurred in 37.9% of MK-2206 versus 21.4% of everolimus-treated patients. Genomic analysis revealed that 57.1% of the patients in the PD group had either deleterious TP53 mutations or ATM mutations or deletions. In contrast, none of the patients in the non-PD group had TP53 or ATM defects. No predictive marker for response was observed in this small dataset.

Conclusions

Dichotomous outcomes are observed when VEGF therapy refractory patients are treated with MK-2206, and MK-2206 does not demonstrate superiority to everolimus. Additionally, mutations in DNA repair genes are associated with early disease progression, indicating that dysregulation of DNA repair is associated with a more aggressive tumor phenotype in RCC.

Ubiquitination and regulation of AURKA identifies a hypoxia-independent E3 ligase activity of VHL

The hypoxia-regulated tumor-suppressor von Hippel-Lindau (VHL) is an E3 ligase that recognizes its substrates as part of an oxygen-dependent prolyl hydroxylase (PHD) reaction, with hypoxia-inducible factor α (HIFα) being its most notable substrate. Here we report that VHL has an equally important function distinct from its hypoxia-regulated activity. We find that Aurora kinase A (AURKA) is a novel, hypoxia-independent target for VHL ubiquitination. In contrast to its hypoxia-regulated activity, VHL mono-, rather than poly-ubiquitinates AURKA, in a PHD-independent reaction targeting AURKA for degradation in quiescent cells, where degradation of AURKA is required to maintain the primary cilium. Tumor-associated variants of VHL differentiate between these two functions, as a pathogenic VHL mutant that retains intrinsic ability to ubiquitinate HIFα is unable to ubiquitinate AURKA. Together, these data identify VHL as an E3 ligase with important cellular functions under both normoxic and hypoxic conditions.

Abstract 1161: A new, therapeutically actionable target for the VHL E3 ubiquitin ligase in renal cell carcinoma

Background: Loss of function of the von Hippel Lindau (VHL) tumor suppressor is a nearly ubiquitous feature of clear cell renal cell carcinoma (ccRCC). The current therapeutic strategies in RCC were developed around knowledge that the VHL E3 ubiquitin ligase targets hypoxia inducible factors (HIFs) for degradation. AURKA is a well-established mitotic kinase and an emerging target in numerous cancers arising from its critical roles in tumor growth and survival. More recently AURKA was discovered to also have important non-mitotic functions in G1/G0 cells, where it activates HDAC6 to regulate microtubule stability. Here we report that AURKA is a novel target for the VHL E3 ligase, which plays an important role in modulating the non-mitotic activity of AURKA.

Methods: In vitro and in vivo ubiquitination assays were performed to establish AURKA as a direct target of VHL. Immunoblot analyses were used to determine AURKA levels in human RCC patient material and VHL deficient cell lines. Immunofluorescence was utilized to assess the impact of VHL-mediated AURKA ubiquitination on microtubule targets using primary cilia.

Results: In this study, we show that AURKA is a novel target for VHL's E3-ligase activity. VHL directly regulates AURKA expression in non-mitotic, quiescent cells by promoting AURKA degradation via the 26S proteasome. The ubiquitination assays showed enhanced AURKA ubiquitination in the presence of VHL. We found that VHL mediates AURKA degradation via a multi-monoubiquitin chain linkage, in contrast to the more traditional and abundant K48-linkage of proteins targeted for proteasome-mediated degradation. Biochemical studies revealed that unlike HIFα recognition by VHL, which requires proline hydroxylation, VHL interacted with, and degraded AURKA independent of its hydroxylation status, suggesting an alternate mechanism for recognition of AURKA. Importantly, using primary cilia as a biomarker for stabile microtubules and activity of AURKA/HDAC6, we showed that the loss of primary cilia observed in VHL-null cells was rescued by alisertib (AURKA inhibitor) and rocilinostat (HDAC6 inhibitor).

Conclusion: In conclusion, the biochemical evidence presented here identifies AURKA as a novel target of VHL's E3 ubiquitin ligase activity. We demonstrate a previously unknown mechanism for VHL mediated multi-mono ubiquitination of AURKA in regulating its non-mitotic functions, important in enabling the G0/G1 transition of cells and maintaining the cilia-centrosome cycle. Importantly, as an alternative to the current HIF related anti-angiogenic therapies, identifying AURKA as a novel VHL target lays the foundation for new therapeutic avenues in RCC, targeted specifically at the epithelial defects associated with VHL-null renal cell carcinoma.

Citation Format: Elshad Hasanov, Guang Chen, Pratim Chowdhury, Justin Weldon, Eric Jonasch, Subrata Sen, Cheryl Lyn Walker, Ruhee Dere. A new, therapeutically actionable target for the VHL E3 ubiquitin ligase in renal cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1161.