Single-cell protein activity analysis identifies recurrence-associated renal tumor macrophages.

Clear cell renal carcinoma (ccRCC) is a heterogeneous disease with a variable post-surgical course. To assemble a comprehensive ccRCC tumor microenvironment (TME) atlas, we performed single-cell RNA sequencing (scRNA-seq) of hematopoietic and non-hematopoietic subpopulations from tumor and tumor-adjacent tissue of treatment-naive ccRCC resections. We leveraged the VIPER algorithm to quantitate single-cell protein activity and validated this approach by comparison to flow cytometry. The analysis identified key TME subpopulations, as well as their master regulators and candidate cell-cell interactions, revealing clinically relevant populations, undetectable by gene-expression analysis. Specifically, we uncovered a tumor-specific macrophage subpopulation characterized by upregulation of TREM2/APOE/C1Q, validated by spatially resolved, quantitative multispectral immunofluorescence. In a large clinical validation cohort, these markers were significantly enriched in tumors from patients who recurred following surgery. The study thus identifies TREM2/APOE/C1Q-positive macrophage infiltration as a potential prognostic biomarker for ccRCC recurrence, as well as a candidate therapeutic target.

Obesity induces PD-1 on macrophages to suppress anti-tumour immunity.

Obesity is a leading risk factor for progression and metastasis of many cancers1,2, yet can in some cases enhance survival3-5 and responses to immune checkpoint blockade therapies, including anti-PD-1, which targets PD-1 (encoded by PDCD1), an inhibitory receptor expressed on immune cells6-8. Although obesity promotes chronic inflammation, the role of the immune system in the obesity-cancer connection and immunotherapy remains unclear. It has been shown that in addition to T cells, macrophages can express PD-19-12. Here we found that obesity selectively induced PD-1 expression on tumour-associated macrophages (TAMs). Type I inflammatory cytokines and molecules linked to obesity, including interferon-γ, tumour necrosis factor, leptin, insulin and palmitate, induced macrophage PD-1 expression in an mTORC1- and glycolysis-dependent manner. PD-1 then provided negative feedback to TAMs that suppressed glycolysis, phagocytosis and T cell stimulatory potential. Conversely, PD-1 blockade increased the level of macrophage glycolysis, which was essential for PD-1 inhibition to augment TAM expression of CD86 and major histocompatibility complex I and II molecules and ability to activate T cells. Myeloid-specific PD-1 deficiency slowed tumour growth, enhanced TAM glycolysis and antigen-presentation capability, and led to increased CD8+ T cell activity with a reduced level of markers of exhaustion. These findings show that obesity-associated metabolic signalling and inflammatory cues cause TAMs to induce PD-1 expression, which then drives a TAM-specific feedback mechanism that impairs tumour immune surveillance. This may contribute to increased cancer risk yet improved response to PD-1 immunotherapy in obesity.

The Transcription Factor Bhlhe40 Programs Mitochondrial Regulation of Resident CD8+ T Cell Fitness and Functionality.

Tissue-resident memory CD8+ T (Trm) cells share core residency gene programs with tumor-infiltrating lymphocytes (TILs). However, the transcriptional, metabolic, and epigenetic regulation of Trm cell and TIL development and function is largely undefined. Here, we found that the transcription factor Bhlhe40 was specifically required for Trm cell and TIL development and polyfunctionality. Local PD-1 signaling inhibited TIL Bhlhe40 expression, and Bhlhe40 was critical for TIL reinvigoration following anti-PD-L1 blockade. Mechanistically, Bhlhe40 sustained Trm cell and TIL mitochondrial fitness and a functional epigenetic state. Building on these findings, we identified an epigenetic and metabolic regimen that promoted Trm cell and TIL gene signatures associated with tissue residency and polyfunctionality. This regimen empowered the anti-tumor activity of CD8+ T cells and possessed therapeutic potential even at an advanced tumor stage in mouse models. Our results provide mechanistic insights into the local regulation of Trm cell and TIL function.

Tivozanib plus nivolumab versus tivozanib monotherapy in patients with renal cell carcinoma following an immune checkpoint inhibitor: results of the phase 3 TiNivo-2 Study.

BACKGROUND: Immune checkpoint inhibitors (ICIs) and vascular endothelial growth factor receptor tyrosine kinase inhibitors are cornerstones of first-line treatment for advanced renal cell carcinoma; however, optimal treatment sequencing after progression is unknown. This study aimed to assess clinical outcomes of tivozanib-nivolumab versus tivozanib monotherapy in patients with metastatic renal cell carcinoma who have progressed following one or two lines of therapy in the post-ICI setting. METHODS: TiNivo-2 is a multicentre, randomised, open-label, phase 3 trial at 190 sites across 16 countries, in Australia, Europe, North America, and South America. Patients with advanced renal cell carcinoma and progression during or after one to two previous lines of therapy (including one ICI) were randomised 1:1 to tivozanib (0·89 mg per day, orally) plus nivolumab (480 mg every 4 weeks, intravenously) or tivozanib (1·34 mg per day, orally). Randomisation was stratified by immediate previous therapy (ICI or non-ICI) and International Metastatic Renal Cell Carcinoma Database Consortium risk category. The primary endpoint was progression-free survival (PFS), defined as the time from randomisation to first documentation of objective progressive disease according to RECIST 1·1 or death from any cause, whichever came first, by independent radiology review. Efficacy was evaluated in the intention-to-treat population, and safety was assessed in patients who received one or more doses of the study drug. This trial was registered on ClinicalTrials.gov (NCT04987203) and is active and not recruiting. FINDINGS: From Nov 4, 2021, to June 16, 2023, 343 patients were randomly assigned to tivozanib-nivolumab (n=171) or tivozanib monotherapy (n=172). Median follow-up was 12·0 months. Median PFS was 5·7 months (95% CI 4·0-7·4) with tivozanib-nivolumab and 7·4 months (5·6-9·2) with tivozanib monotherapy (hazard ratio 1·10, 95% CI 0·84-1·43; p=0·49). Among those with an ICI as their immediate previous therapy (n=244), median PFS was 7·4 months (95% CI 5·6-9·6) with tivozanib-nivolumab and 9·2 months (7·4-10·0) with tivozanib monotherapy. With non-ICIs as the most recent therapy, lower median PFS was observed, with no difference between groups (tivozanib-nivolumab 3·7 months [95% CI 2·7-5·4] and with tivozanib monotherapy 3·7 months [1·9-7·2]). Serious adverse events occurred in 54 (32%) of 168 patients receiving tivozanib-nivolumab and 64 (37%) of 171 patients receiving tivozanib monotherapy. One (<1%) treatment-related death occurred (tivozanib group). INTERPRETATION: These data further support that ICI rechallenge should be discouraged in patients with advanced renal cell carcinoma. Furthermore, these data suggest that tivozanib monotherapy has efficacy in the post-ICI setting. FUNDING: Aveo Pharmaceuticals.

Belzutifan for patients with von Hippel-Lindau disease-associated CNS haemangioblastomas (LITESPARK-004): a multicentre, single-arm, phase 2 study.

BACKGROUND: The first-in-class hypoxia-inducible factor-2α inhibitor, belzutifan, showed clinically meaningful antitumour activity in von Hippel-Lindau (VHL) disease-associated neoplasms in the ongoing, single-arm, phase 2 LITESPARK-004 study. We aimed to investigate antitumour activity with an additional 16 months of follow-up and present updated results for the subgroup of patients with CNS haemangioblastomas. METHODS: In the multicentre, single-arm, phase 2 LITESPARK-004 study, adults (aged ≥18 years) from 11 cancer centres or hospitals in the USA, Denmark, France, and the UK, with germline VHL alterations, at least one measurable renal cell carcinoma tumour, no renal cell carcinoma tumour greater than 3 cm requiring immediate surgical intervention, an Eastern Cooperative Oncology Group performance status 0 or 1, and no previous systemic therapy received oral belzutifan 120 mg once daily until unacceptable toxicity, disease progression, or patient decision to withdraw. The primary endpoint, evaluated in patients with CNS haemangioblastomas, was the proportion of patients with an objective response per RECIST version 1.1 by an independent review committee. We assessed response using two approaches. In approach 1, we evaluated all measurable (≥1 cm maximum diameter) or non-measurable lesions at baseline, including both the solid lesion and the associated cystic component if present. In approach 2, we evaluated only baseline lesions with a measurable (≥1 cm maximum diameter) solid lesion. Antitumour activity was assessed in all patients who received at least one dose of belzutifan. This study is no longer recruiting but is ongoing, and is registered with Clinicaltrials.gov, NCT03401788. FINDINGS: Between May 31, 2018, and March 29, 2019, of 67 patients screened, 61 (32 [52%] male and 29 [48%] female) were enrolled; 50 (82%) had at least one CNS haemangioblastoma evaluable at baseline (184 total lesions). Median follow-up for the 50 patients with CNS haemangioblastomas was 38·0 months (IQR 36·7-40·1). In approach 1, 22 of 50 patients (44% [95% CI 30-59]) had an objective response. In approach 2, 19 of 25 patients (76% [55-91] had an objective response. 23 (46%) of 50 patients had a grade 3-5 all-cause adverse event. 19 (38%) patients reported grade 3 adverse events, the most common of which was anaemia (in 6 [12%] patients). Two of 50 patients (4%) reported grade 4 events (retinal vein occlusion and embolism). Two patients died owing to adverse events not considered treatment-related (suicide and toxicity to various agents). INTERPRETATION: Belzutifan showed meaningful antitumour activity in VHL disease-associated CNS haemangioblastomas that was sustained for more than 3 years of treatment. These results continue to support belzutifan as a systemic treatment option for patients with VHL disease-related CNS haemangioblastomas. FUNDING: Merck Sharp & Dohme, National Institutes of Health, and National Cancer Institute.

Long-Term Survival in Patients With Relapsed/Refractory Advanced Renal Cell Carcinoma Treated With Tivozanib: Analysis of the Phase III TIVO-3 Trial.

BACKGROUND: Tivozanib is an oral vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI) with efficacy in advanced renal cell carcinoma (RCC). Long-term exploratory analyses from the TIVO-3 trial in relapsed/refractory (R/R) RCC including patients (26%) with prior immuno-oncology (IO) therapy are reported. METHODS: Patients with R/R advanced RCC that progressed with 2 or 3 prior systemic therapies (≥1 VEGFR TKI) were randomized to tivozanib 1.5 mg QD or sorafenib 400 mg BID, stratified by IMDC risk and previous therapy. Safety, investigator-assessed long-term progression-free survival (LT-PFS), and serial overall survival (OS) were assessed. RESULTS: Mean time on treatment was 11.0 months with tivozanib (n = 175) and 6.3 months with sorafenib (n = 175). Fewer grade ≥3 treatment-related adverse events occurred with tivozanib (46%) than sorafenib (55%). Dose modification rates were lower with tivozanib than sorafenib across age/prior IO subgroups; prior IO therapy did not impact dose reductions or discontinuations in either arm. Landmark LT-PFS rates were higher with tivozanib (3 years: 12.3% vs 2.4%; 4 years: 7.6% vs 0%). After 22.8 months mean follow-up, the OS HR was 0.89 (95% CI, 0.70-1.14); when conditioned on 12-month landmark PFS, tivozanib showed significant OS improvement over sorafenib (HR, 0.45; 95% CI, 0.22-0.91; 2-sided P = .0221). CONCLUSIONS: Tivozanib demonstrated a consistent safety profile and long-term survival benefit in patients with R/R advanced RCC who were alive and progression free at 12 months. These post hoc exploratory analyses of LT-PFS and conditional OS support a clinically meaningful improvement with tivozanib versus sorafenib in this advanced RCC population.

A phase 1b open-label study to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of py314 in combination with pembrolizumab in patients with advanced renal cell carcinoma.

Checkpoint inhibition (CPI) is a standard therapeutic approach in metastatic renal cell carcinoma (RCC). However, not all patients respond to CPI, and the immune suppressive characteristics of the RCC tumor microenvironment may contribute to treatment failure. Triggering Receptor Expressed on Myeloid Cells-2 (TREM2) is a transmembrane protein expressed on a subset of myeloid cells with M2-like anti-inflammatory properties that has previously been associated with disease recurrence after nephrectomy and poor outcomes when expressed at high levels. PY314 is a humanized monoclonal antibody targeting TREM2 that depletes tumor-associated macrophages. In this study, the combination of PY314 and pembrolizumab was investigated in patients with CPI-refractory RCC. Eligible patients had clear cell RCC with disease progression on prior CPI either in combination or sequentially with VEGF-TKI. Patients were treated with PY314 10 mg/kg in combination with pembrolizumab 200 mg IV every 21 days. The primary objective was to assess safety and tolerability and secondary objectives included pharmacokinetics and anti-tumor activity by RECIST v1.1. Seventeen patients were enrolled with a median age of 67 years, 82% male, 100% had prior CPI, and 76% had received three or more prior lines of therapy. The combination of PY314 and pembrolizumab demonstrated an acceptable safety profile with 47.1% any grade treatment-related adverse events (AE) (including only 5.9% grade ≥ 3), the most common being fatigue, pyrexia, nausea, and infusion-related reactions. One patient achieved a partial response (6%), and four patients had stable disease (24%) as their best response. The median PFS was 1.4 months (95% CI 1.2- 3.8). The combination of PY314 and pembrolizumab was safe, but the limited anti-tumor effect observed suggests that TREM2 targeting in conjunction with PD-1 blockade may not overcome resistance to prior CPI. Further investigation is warranted to determine if improved efficacy can be achieved in IO-naïve settings. Trial Registration: NCT04691375.

von Hippel- Lindau syndrome-related congenital polycythemia and response to belzutifan.

Not available.

Avelumab Plus Axitinib as First-Line Therapy for Advanced Renal Cell Carcinoma: Long-Term Results from the JAVELIN Renal 100 Phase Ib Trial.

BACKGROUND: Progression-free survival was significantly longer in patients who received avelumab plus axitinib versus sunitinib as first-line treatment for advanced renal cell carcinoma (aRCC) in a randomized phase III trial. We report long-term safety and efficacy of avelumab plus axitinib as first-line treatment for patients with aRCC from the JAVELIN Renal 100 phase Ib trial (NCT02493751). MATERIALS AND METHODS: In this open-label, multicenter, phase Ib study, patients with untreated aRCC received avelumab 10 mg/kg every 2 weeks plus axitinib 5 mg twice daily or with axitinib for 7 days followed by avelumab plus axitinib. Safety and efficacy were assessed in all patients receiving at least one dose of avelumab or axitinib. RESULTS: Overall, 55 patients were enrolled and treated. Median follow-up was 55.7 months (95% CI, 54.5-58.7). Treatment-related adverse events of any grade or grade ≥3 occurred in 54 (98.2%) and 34 (61.8%) patients, respectively. The confirmed objective response rate was 60.0% (95% CI, 45.9-73.0), including complete response in 10.9% of patients. Median duration of response was 35.9 months (95% CI, 12.7-52.9); the probability of response was 65.8% (95% CI, 46.7-79.4) at 2 years. Median progression-free survival was 8.3 months (95% CI, 5.3-32.0). Median overall survival was not reached (95% CI, 40.8-not estimable); the 5-year overall survival rate was 57.3% (95% CI, 41.2-70.5). CONCLUSION: Five-year follow-up for combination treatment with avelumab plus axitinib in previously untreated patients with aRCC showed long-term clinical activity with no new safety signals, supporting use of this regimen within its approved indication in clinical practice (Clinicaltrials.gov NCT02493751).

Leptin Augments Antitumor Immunity in Obesity by Repolarizing Tumor-Associated Macrophages.

Although obesity can promote cancer, it may also increase immunotherapy efficacy in what has been termed the obesity-immunotherapy paradox. Mechanisms of this effect are unclear, although obesity alters key inflammatory cytokines and can promote an inflammatory state that may modify tumor-infiltrating lymphocytes and tumor-associated macrophage populations. To identify mechanisms by which obesity affects antitumor immunity, we examined changes in cell populations and the role of the proinflammatory adipokine leptin in immunotherapy. Single-cell RNAseq demonstrated that obesity decreased tumor-infiltrating lymphocyte frequencies, and flow cytometry confirmed altered macrophage phenotypes with lower expression of inducible NO synthase and MHC class II in tumors of obese animals. When treated with anti-programmed cell death protein 1 (PD-1) Abs, however, obese mice had a greater absolute decrease in tumor burden than lean mice and a repolarization of the macrophages to inflammatory M1-like phenotypes. Mechanistically, leptin is a proinflammatory adipokine that is induced in obesity and may mediate enhanced antitumor immunity in obesity. To directly test the effect of leptin on tumor growth and antitumor immunity, we treated lean mice with leptin and observed tumors over time. Treatment with leptin, acute or chronic, was sufficient to enhance antitumor efficacy similar to anti-PD-1 checkpoint therapy. Further, leptin and anti-PD-1 cotreatment may enhance antitumor effects consistent with an increase in M1-like tumor-associated macrophage frequency compared with non-leptin-treated mice. These data demonstrate that obesity has dual effects in cancer through promotion of tumor growth while simultaneously enhancing antitumor immunity through leptin-mediated macrophage reprogramming.

The Impact of Nonsteroidal Anti-Inflammatory Drugs, Beta Blockers, and Metformin on the Efficacy of Anti-PD-1 Therapy in Advanced Melanoma.

Anti-programmed cell death protein-1 (anti-PD-1) therapy has greatly improved outcomes of patients with melanoma; however, many fail to respond. Although preclinical studies suggest a potentially synergistic relationship with anti-PD-1 therapy and certain concurrent medications, their clinical role remains unclear. Here, we retrospectively evaluated the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and other drugs in 330 patients with melanoma treated with anti-PD-1 therapy from four academic centers. In the cohort, 37% of patients used NSAIDs including aspirin (acetylsalicylic acid; ASA; 47%), cyclooxygenase (COX)-2 inhibitors (2%), and non-ASA/nonselective COX inhibitor NSAIDs (59%). The objective response rates (ORRs) were similar in patients with NSAID (43.4%) and no NSAID (41.3%) use with no significant difference in overall suvival (OS). There was a trend toward improved progression-free survival (PFS) in patients who took NSAIDs (median PFS: 8.5 vs. 5.2 months; p = .054). Most patients (71.3%) took NSAIDs once daily or as needed. Multivariate analysis did not reveal an association with NSAID use with ORR, PFS, or OS. Concurrent use of metformin or beta blockers did not affect ORR, PFS, or OS. Our study found no conclusive association of concurrent NSAID or other medication use with improved outcomes in patients with melanoma treated with anti-PD-1 therapy. Larger and more systematic analysis is required to confirm these findings.

Association of body-mass index and outcomes in patients with metastatic melanoma treated with targeted therapy, immunotherapy, or chemotherapy: a retrospective, multicohort analysis.

BACKGROUND: Obesity has been linked to increased mortality in several cancer types; however, the relation between obesity and survival outcomes in metastatic melanoma is unknown. The aim of this study was to examine the association between body-mass index (BMI) and progression-free survival or overall survival in patients with metastatic melanoma who received targeted therapy, immunotherapy, or chemotherapy. METHODS: This retrospective study analysed independent cohorts of patients with metastatic melanoma assigned to treatment with targeted therapy, immunotherapy, or chemotherapy in randomised clinical trials and one retrospective study of patients treated with immunotherapy. Patients were classified according to BMI, following the WHO definitions, as underweight, normal, overweight, or obese. Patients without BMI and underweight patients were excluded. The primary outcomes were the associations between BMI and progression-free survival or overall survival, stratified by treatment type and sex. We did multivariable analyses in the independent cohorts, and combined adjusted hazard ratios in a mixed-effects meta-analysis to provide a precise estimate of the association between BMI and survival outcomes; heterogeneity was assessed with meta-regression analyses. Analyses were done on the predefined intention-to-treat population in the randomised controlled trials and on all patients included in the retrospective study. FINDINGS: The six cohorts consisted of a total of 2046 patients with metastatic melanoma treated with targeted therapy, immunotherapy, or chemotherapy between Aug 8, 2006, and Jan 15, 2016. 1918 patients were included in the analysis. Two cohorts containing patients from randomised controlled trials treated with targeted therapy (dabrafenib plus trametinib [n=599] and vemurafenib plus cobimetinib [n=240]), two cohorts containing patients treated with immunotherapy (one randomised controlled trial of ipilimumab plus dacarbazine [n=207] and a retrospective cohort treated with pembrolizumab, nivolumab, or atezolizumab [n=331]), and two cohorts containing patients treated with chemotherapy (two randomised controlled trials of dacarbazine [n=320 and n=221]) were classified according to BMI as normal (694 [36%] patients), overweight (711 [37%]), or obese (513 [27%]). In the pooled analysis, obesity, compared with normal BMI, was associated with improved survival in patients with metastatic melanoma (average adjusted hazard ratio [HR] 0·77 [95% CI 0·66-0·90] for progression-free survival and 0·74 [0·58-0·95] for overall survival). The survival benefit associated with obesity was restricted to patients treated with targeted therapy (HR 0·72 [0·57-0·91] for progression-free survival and 0·60 [0·45-0·79] for overall survival) and immunotherapy (HR 0·75 [0·56-1·00] and 0·64 [0·47-0·86]). No associations were observed with chemotherapy (HR 0·87 [0·65-1·17, pinteraction=0·61] for progression-free survival and 1·03 [0·80-1·34, pinteraction=0·01] for overall survival). The association of BMI with overall survival for patients treated with targeted and immune therapies differed by sex, with inverse associations in men (HR 0·53 [0·40-0·70]), but no associations observed in women (HR 0·85 [0·61-1·18, pinteraction=0·03]). INTERPRETATION: Our results suggest that in patients with metastatic melanoma, obesity is associated with improved progression-free survival and overall survival compared with those outcomes in patients with normal BMI, and that this association is mainly seen in male patients treated with targeted or immune therapy. These results have implications for the design of future clinical trials for patients with metastatic melanoma and the magnitude of the benefit found supports further investigation of the underlying mechanism of these associations. FUNDING: ASCO/CCF Young Investigator Award, ASCO/CCF Career Development Award, MD Anderson Cancer Center (MDACC) Melanoma Moonshot Program, MDACC Melanoma SPORE, and the Dr Miriam and Sheldon G Adelson Medical Research Foundation.

Immune Checkpoint Inhibitor Therapy in Patients With Autoimmune Disease.

Immune checkpoint inhibitors have demonstrated efficacy across many cancer types in numerous clinical trials. However, because patients with preexisting autoimmune disease were excluded from these seminal trials, there are serious gaps in knowledge regarding the efficacy-and in particular the safety-of these transformative agents in patients with autoimmune disease. The safety of immune checkpoint inhibitors in this population has been an important concern, since these agents unleash immune activation, a potentially dangerous situation for patients with already heightened and aberrant immune function. Several retrospective studies have begun to address this question, finding that autoimmunity is often exacerbated by immune checkpoint inhibitor therapy, but is generally manageable with standard treatment algorithms and close multidisciplinary monitoring. Further, the activity of these agents appears to be comparable to that seen in unselected patients. Here we detail the experience with immune checkpoint inhibitors in patients with autoimmune disease.

Phase II Trial of Intermittent Therapy in Patients with Metastatic Renal Cell Carcinoma Treated with Front-line Ipilimumab and Nivolumab.

INTRODUCTION: The combination of ipilimumab/nivolumab is approved for patients with treatment-naïve, intermediate-, and poor-risk metastatic renal cell carcinoma (mRCC), but duration of therapy and safety/efficacy of reinduction at progression is unknown. A phase II trial of intermittent ipilimumab/nivolumab with reinduction at progression was conducted (NCT03126331). PATIENTS AND METHODS: Patients with treatment-naïve mRCC were treated with induction ipilimumab/nivolumab followed by up to 24 weeks of maintenance nivolumab. Patients who achieved a complete response (CR) or partial response (PR) were eligible for inclusion and entered a treatment-free observation period. Patients were restaged every 12 weeks. Patients with no disease progression (PD) remained off therapy. Upon PD, patients were re-challenged with 2 doses of ipilimumab/nivolumab every 3 weeks. Study objectives were to estimate success rate of observation in patients who achieve a CR/PR, and to assess toxicity in patients undergoing reinduction. The study accrued slower than expected and was closed prior to the anticipated accrual goal of 20 patients. RESULTS: Nine patients were included; 89% male, median age 57, 67% clear-cell histology, and 78% intermediate-risk by IMDC criteria. Response to ipilimumab/nivolumab followed by nivolumab maintenance prior to enrollment was 33% CR and 67% PR. Most (78%) patients have remained off therapy, with a median treatment-free interval (TFI) of 34.3 months (range, 8.7-41.8). Two patients had PD off therapy and received 2 cycles of reinduction ipilimumab and nivolumab. No grade 3 or greater toxicities occurred with reinduction. Both patients developed PD at their first scans after reinduction. CONCLUSION: This prospective study demonstrates that patients with a radiographic response to ipilimumab/nivolumab can have prolonged treatment-free intervals. Further studies of de-escalation strategies are warranted. TRIAL REGISTRATION: NCT03126331 [Date of registration 4/27/2017; https://clinicaltrials.gov/ct2/show/NCT03126331].

A First-in-Human Phase 1 Study of a Tumor-Directed RNA-Interference Drug against HIF2α in Patients with Advanced Clear Cell Renal Cell Carcinoma.

PURPOSE: ARO-HIF2 is an siRNA drug designed to selectively target hypoxia-inducible factor-2α (HIF2α) interrupting downstream pro-oncogenic signaling in clear cell renal cell carcinoma (ccRCC). The aims of this Phase 1 study (AROHIF21001) were to evaluate safety, tolerability, pharmacokinetics, and establish a recommended Phase 2 dose. PATIENTS AND METHODS: Subjects with ccRCC and progressive disease after at least 2 prior therapies that included VEGF and immune checkpoint inhibitors were progressively enrolled into dose-escalation cohorts of ARO-HIF2 administered intravenously at 225, 525, or 1,050 mg weekly. RESULTS: Twenty-six subjects received ARO-HIF2. The most common treatment emergent adverse events (AE) irrespective of causality were fatigue (50.0%), dizziness (26.9%), dyspnea (23.1%), and nausea (23.1%). Four subjects (15.4%) had treatment-related serious AEs. AEs of special interest included neuropathy, hypoxia, and dyspnea. ARO-HIF2 was almost completely cleared from plasma circulation within 48 hours with minimal renal clearance. Reductions in HIF2α were observed between pre- and post-dosing tumor biopsies, but the magnitude was quite variable. The objective response rate was 7.7% and the disease control rate was 38.5%. Responses were accompanied by ARO-HIF2 uptake in tumor cells, HIF2α downregulation, as well as rapid suppression of tumor produced erythropoietin (EPO) in a patient with paraneoplastic polycythemia. CONCLUSIONS: ARO-HIF2 downregulated HIF2α in advanced ccRCC-inhibiting tumor growth in a subset of subjects. Further development was hampered by off-target neurotoxicity and low response rate. This study provides proof of concept that siRNA can target tumors in a specific manner.

HIF-2α expression and metabolic signaling require ACSS2 in clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is an aggressive cancer driven by VHL loss and aberrant HIF-2α signaling. Identifying means to regulate HIF-2α thus has potential therapeutic benefit. Acetyl-CoA synthetase 2 (ACSS2) converts acetate to acetyl-CoA and is associated with poor patient prognosis in ccRCC. Here we tested the effects of ACSS2 on HIF-2α and cancer cell metabolism and growth in ccRCC models and clinical samples. ACSS2 inhibition reduced HIF-2α levels and suppressed ccRCC cell line growth in vitro, in vivo, and in cultures of primary ccRCC patient tumors. This treatment reduced glycolytic signaling, cholesterol metabolism, and mitochondrial integrity, all of which are consistent with loss of HIF-2α. Mechanistically, ACSS2 inhibition decreased chromatin accessibility and HIF-2α expression and stability. While HIF-2α protein levels are widely regulated through pVHL-dependent proteolytic degradation, we identify a potential pVHL-independent pathway of degradation via the E3 ligase MUL1. We show that MUL1 can directly interact with HIF-2α and that overexpression of MUL1 decreased HIF-2α levels in a manner partially dependent on ACSS2. These findings identify multiple mechanisms to regulate HIF-2α stability and ACSS2 inhibition as a strategy to complement HIF-2α-targeted therapies and deplete pathogenically stabilized HIF-2α.

Belzutifan for von Hippel-Lindau Disease: Pancreatic Lesion Population of the Phase 2 LITESPARK-004 Study.

PURPOSE: Primary analysis of the ongoing, single-arm, phase 2 LITESPARK-004 study (NCT03401788) showed clinically meaningful antitumor activity in von Hippel-Lindau (VHL) disease-associated renal cell carcinoma (RCC) and other neoplasms with belzutifan treatment. We describe results of belzutifan treatment for VHL disease-associated pancreatic lesions [pancreatic neuroendocrine tumors (pNET) and serous cystadenomas]. PATIENTS AND METHODS: Adults with VHL diagnosis based on germline VHL alteration, ≥1 measurable RCC tumor, no renal tumor >3 cm or other VHL neoplasm requiring immediate surgery, Eastern Cooperative Oncology Group performance status of 0 or 1, and no prior systemic anticancer treatment received belzutifan 120 mg once daily. End points included objective response rate (ORR), duration of response (DOR), progression-free survival (PFS), and linear growth rate (LGR) in all pancreatic lesions and pNETs per RECIST version 1.1 by independent review committee, and safety. RESULTS: All 61 enrolled patients (100%) had ≥1 pancreatic lesion and 22 (36%) had ≥1 pNET measurable at baseline. Median follow-up was 37.8 months (range, 36.1-46.1). ORR was 84% [51/61; 17 complete responses (CR)] in pancreatic lesions and 91% (20/22; 7 CRs) in pNETs. Median DOR and median PFS were not reached in pancreatic lesions or pNETs. After starting treatment, median LGR for pNETs was -4.2 mm per year (range, -7.9 to -0.8). Eleven patients (18%) had ≥1 grade 3 treatment-related adverse event (AE). No grade 4 or 5 treatment-related AEs occurred. CONCLUSIONS: Belzutifan continued to show robust activity and manageable safety in VHL disease-associated pNETs.