Lana Hamieh

Mutations in TSC1, TSC2, and MTOR Are Associated with Response to Rapalogs in Patients with Metastatic Renal Cell Carcinoma

Purpose: We examined the hypothesis that mutations in mTOR pathway genes are associated with response to rapalogs in metastatic renal cell carcinoma (mRCC). Experimental Design: We studied a cohort of mRCC patients who were treated with mTOR inhibitors with distinct clinical outcomes. Tumor DNA from 79 subjects was successfully analyzed for mutations using targeted next-generation sequencing of 560 cancer genes. Responders were defined as those with partial response (PR) by RECIST v1.0 or stable disease with any tumor shrinkage for 6 months or longer. Nonresponders were defined as those with disease progression during the first 3 months of therapy. Fisher exact test assessed the association between mutation status in mTOR pathway genes and treatment response. Results: Mutations in MTOR, TSC1, or TSC2 were more common in responders, 12 (28%) of 43, than nonresponders, 4 (11%) of 36 (P = 0.06). Mutations in TSC1 or TSC2 alone were also more common in responders, 9 (21%), than nonresponders, 2(6%), (P = 0.05). Furthermore, 5 (42%) of 12 subjects with PR had mutations in MTOR, TSC1, or TSC2 compared with 4 (11%) of 36 nonresponders (P = 0.03). Eight additional non-mTOR pathway genes were found to be mutated in at least 4 of 79 tumors (5%); none were associated positively with response. Conclusions: In this cohort of mRCC patients, mutations in MTOR, TSC1, or TSC2 were more common in patients who experienced clinical benefit from rapalogs than in those who progressed. However, a substantial fraction of responders (24 of 43, 56%) had no mTOR pathway mutation identified. Clin Cancer Res; 22(10); 2445–52. ©2016 AACR. See related commentary by Voss and Hsieh, p. 2320

Optimizing systemic therapy for metastatic renal cell carcinoma beyond the first-line setting.

The introduction of molecularly targeted therapies (TTs) has transformed the management of metastatic renal cell carcinoma (mRCC). Within a relatively short period of time, systemic treatment of mRCC has evolved from a disease treated only by cytokines to a disease where TT is the cornerstone of patient management. Since the approval of sorafenib, an inhibitor of vascular endothelial growth factor receptor (VEGFR), in December 2005, 7 drugs have been introduced that have provided a high level of clinical efficacy in patients with mRCC, with a median survival of ~30 months in an unselected patient population that generally fits trials eligibility. Despite such success, advancements in therapies have reached a plateau: different combinations of targeted agents have not demonstrated additional benefit mainly owing to toxicity concerns, and some novel agents have failed to show benefit over approved drugs in clinics. In this review, we aim to focus on optimizing selection of agents in mRCC after progression on first-line TT. We also review how new drugs may transform existing guidelines and break through the current plateau reached with approved agents.

Durable clinical benefit in metastatic renal cell carcinoma patients who discontinue PD-1/PD-L1 therapy for immune-related adverse events (irAEs)

mRCC patients who had a clinical response to PD-1/PD-L1 blockade and discontinued treatment due to irAE continued to derive prolonged clinical benefit after treatment was stopped. Current clinical trials are exploring customized approaches to application of PD-1/PD-L1 blockade. The current standard of care for treatment of metastatic renal cell carcinoma (mRCC) patients is PD-1/PD-L1 inhibitors until progression or toxicity. Here, we characterize the clinical outcomes for 19 mRCC patients who experienced an initial clinical response (any degree of tumor shrinkage), but after immune-related adverse events (irAE) discontinued all systemic therapy. Clinical baseline characteristics, outcomes, and survival data were collected. The primary endpoint was time to progression from the date of treatment cessation (TTP). Most patients had clear cell histology and received anti–PD–1/PD-L1 therapy as second-line or later treatment. Median time on PD-1/PD-L1 therapy was 5.5 months (range, 0.7–46.5) and median TTP was 18.4 months (95% CI, 4.7–54.3) per Kaplan–Meier estimation. The irAEs included arthropathies, ophthalmopathies, myositis, pneumonitis, and diarrhea. We demonstrate that 68.4% of patients (n = 13) experienced durable clinical benefit off treatment (TTP of at least 6 months), with 36% (n = 7) of patients remaining off subsequent treatment for over a year after their last dose of anti–PD-1/PD-L1. Three patients with tumor growth found in a follow-up visit, underwent subsequent surgical intervention, and remain off systemic treatment. Nine patients (47.4%) have ongoing irAEs. Our results show that patients who benefitted clinically from anti–PD-1/PD-L1 therapy can experience sustained beneficial responses, not needing further therapies after the initial discontinuation of treatment due to irAEs. Investigation of biomarkers indicating sustained benefit to checkpoint blockers are needed. Cancer Immunol Res; 6(4); 402–8. ©2018 AACR.

Expression profiles of immune-related genes are associated with neoadjuvant ipilimumab clinical benefit

ABSTRACT Purpose: Patients with regionally advanced melanoma were treated with neoadjuvant ipilimumab in a previously reported study (PLOS One 2014). Gene expression profiles of tumors of treated patients were investigated for their association with immunotherapeutic benefit. Methods: Patients were treated with ipilimumab (10 mg/kg intravenously every 3 weeks × 2 doses) before and after surgery. Tumor specimens were obtained at baseline and at definitive surgery (weeks 6–8). Gene expression profiling was performed on the tumor biopsies of 27 patients. The primary endpoint was mRNA expression profiling using U133A 2.0 Affymetrix gene chips. Significance analysis of microarrays was performed to test the association of each gene with outcome. Pathway analysis was performed using Ingenuity Pathway Analysis software. The Benjamini and Hochberg method was used to adjust for multiple testing in the pathway analysis. Results: Pathway analysis identified biologically relevant pathways enriched with genes that are significantly associated with clinical outcome at baseline in relation to relapse-free survival (RFS) and disease non-progression (as assessed preoperatively at week 6) as well as early on-treatment (RFS and overall survival). The molecules and pathways that achieved differential expression of highest statistical significance were notably immune related. Association of the gene signature with clinical outcome overlapped between baseline and on-treatment specimens and across clinical endpoints tested. Conclusion: Gene expression profiling identified a signature reflecting an immune active and proinflammatory tumor microenvironment that derived clinical benefit from neoadjuvant ipilimumab at baseline and early on-treatment. These findings warrant further investigation in relation to ipilimumab and other immunotherapeutics.

Pancreatic PEComa is a novel member of the family of tuberous sclerosis complex-associated tumors: case report and review of the literature

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder with variable penetrance and a wide spectrum of disease manifestations even within the same family. Major diagnostic criteria for TSC include several distinct neoplasms, including facial angiofibroma, cardiac rhabdomyoma, lymphangioleiomyomatosis, subependymal giant cell astrocytoma, and renal angiomyolipoma. Germline mutations in either of two genes, TSC1 and TSC2, which code for hamartin and tuberin, respectively, cause TSC. Hamartin and tuberin, along with a third protein, TBC1D7, function as a heterocomplex to regulate activation of mTOR complex 1 (mTORC1) through regulation of the rheb GTPase. [5] Loss-of-function mutations in the TSC1 or TSC2 gene lead to activation of mTORC1, which is a direct contributor to the growth of these tumors, and this abnormal activation can be therapeutically blocked by rapamycin and its analogs, such as everolimus. [3] Although not completely separable clinically, TSC1 mutations are associated with overall milder disease severity than TSC2 mutations. The spectrum of clinical features of TSC continues to evolve. More recently, liver angiomyolipomas and pancreatic neuroendocrine tumors (NETs) have been described as manifestations of TSC. [4], [8] Little is known about other types of pancreatic neoplasms associated with TSC. Here, we describe multiple perivascular epithelioid cell tumors (PEComas) in the pancreas of a patient with TSC and provide proof of TSCrelated origin of these PEComas.

Effect of Metformin Use on Survival Outcomes in Patients With Metastatic Renal Cell Carcinoma

Micro‐Abstract In light of the emerging evidence of the antineoplastic potential of metformin, we investigated its effect on survival outcomes in metastatic renal cell carcinoma using a large clinical trial database. Although metformin did not affect survival in the overall cohort, it conferred a survival advantage in diabetic metastatic renal cell carcinoma patients treated with sunitinib. Introduction: Observational studies have suggested that metformin use is associated with favorable outcomes in several cancers. For renal cell carcinoma (RCC), data have been limited. Therefore, we investigated the effect of metformin on survival in metastatic RCC (mRCC) using a large clinical trial database. Patients and Methods: We conducted a retrospective analysis of patients with mRCC in phase II and III clinical trials. The overall survival (OS) in metformin users was compared with that of users of other antidiabetic agents and those not using antidiabetic agents. Progression‐free survival, objective response rate, and adverse events were secondary endpoints. Subgroup analyses were conducted after stratifying by class of therapy, type of vascular endothelial growth factor tyrosine kinase inhibitors, and International Metastatic RCC Database Consortium (IMDC) risk groups. Results: We identified 4736 patients with mRCC, including 486 with diabetes, of whom 218 (4.6%) were taking metformin. Metformin use did not affect OS when compared with users of other antidiabetic agents or those without diabetes. Furthermore, metformin use did not confer an OS advantage when stratified by class of therapy and IMDC risk group. However, in diabetic patients receiving sunitinib (n = 128), metformin use was associated with an improvement in OS compared with users of other antidiabetic agents (29.3 vs. 20.9 months, respectively; hazard ratio, 0.051; 95% confidence interval, 0.009‐0.292; P = .0008). Conclusion: In the present study, we found a survival benefit for metformin use in mRCC patients treated with sunitinib. Clinical and preclinical studies are warranted to validate our results and guide the use of metformin in the clinic.

Nipple Angiofibromas with Loss of TSC2 Are Associated with Tuberous Sclerosis Complex

Nevertheless, our ability to identify meaningful differences between these two populations suggests that this is a reasonable cutpoint. One hypothesis for the increasing incidence rates of early-onset BCC has been increased awareness and skin surveillance. However, lesion size has not decreased over time, as might be anticipated if earlier detection were the underlying cause of increased incidence (Christenson et al., 2005). Our results likewise suggest that early-onset BCC is associated with aggressive histologic characteristics, as opposed to a less aggressive phenotype that might be expected if surveillance bias were operating. Although additional studies are needed, these results suggest there may be underlying biological differences between earlyand late-onset BCC.

Pharmacogenomic Markers of Targeted Therapy Toxicity in Patients with Metastatic Renal Cell Carcinoma

BACKGROUND Targeted therapy (TT) in metastatic renal cell carcinoma (mRCC) may be associated with a high rate of toxicity that undermines treatment efficacy and patient quality of life. Polymorphisms in genes involved in the pharmacokinetic pathways of TTs may predict toxicity. OBJECTIVE To investigate whether selected single-nucleotide polymorphisms (SNPs) in three core genes involved in the metabolism and transport of sunitinib and the mTOR inhibitors everolimus and temsirolimus are associated with adverse events (AEs). DESIGN, SETTING, AND PARTICIPANTS Germline DNA was extracted from blood or normal kidney tissue from mRCC patients of Caucasian ethnicity in two cohorts treated with either sunitinib (n=159) or mTOR inhibitors (n=62). Six SNPs in three candidate genes (CYP3A4: rs2242480, rs4646437, and rs2246709; CYP3A5: rs15524; and ABCB1: rs2032582 and rs1045642) were analyzed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Primary endpoints were grade ≥3 AEs for all patients; grade ≥3 hypertension in the sunitinib cohort, and any grade pneumonitis in the mTOR inhibitors cohort. A logistic regression model was used to assess the association between SNPs and AEs, with adjustment for relevant clinical factors. RESULTS AND LIMITATIONS In total, 221 samples were successfully genotyped for the selected SNPs. In the sunitinib cohort, the CYP3A4 rs464637 AG variant was associated with a lower risk of high-grade AEs (odds ratio 0.27, 95% confidence interval 0.08-0.88; p=0.03), but no SNPs were associated with hypertension. In the mTOR inhibitor cohort, none of the selected SNPs was associated with analyzed toxicities. CONCLUSIONS We observed an association between CYP3A4 polymorphisms and toxicity outcomes in mRCC patients treated with sunitinib, but not with everolimus or temsirolimus. Our findings are exploratory in nature, and further validation in independent and larger cohorts is needed. PATIENT SUMMARY We found that variants of CYP3A4, a gene involved in drug metabolism, are associated with sunitinib toxicity. This information may help in better selection of patients for targeted therapies in metastatic renal cell carcinoma.

Mechanisms of acquired resistance to rapalogs in metastatic renal cell carcinoma

The mechanistic target of rapamycin (mTOR) is an established therapeutic target in renal cell carcinoma (RCC). Mechanisms of secondary resistance to rapalog therapy in RCC have not been studied previously. We identified six patients with metastatic RCC who initially responded to mTOR inhibitor therapy and then progressed, and had pre-treatment and post-treatment tumor samples available for analysis. We performed deep whole exome sequencing on the paired tumor samples and a blood sample. Sequence data was analyzed using Mutect, CapSeg, Absolute, and Phylogic to identify mutations, copy number changes, and their changes over time. We also performed in vitro functional assays on PBRM1 in RCC cell lines. Five patients had clear cell and one had chromophobe RCC. 434 somatic mutations in 416 genes were identified in the 12 tumor samples. 201 (46%) of mutations were clonal in both samples while 129 (30%) were acquired in the post-treatment samples. Tumor heterogeneity or sampling issues are likely to account for some mutations that were acquired in the post-treatment samples. Three samples had mutations in TSC1; one in PTEN; and none in MTOR. PBRM1 was the only gene in which mutations were acquired in more than one post-treatment sample. We examined the effect of PBRM1 loss in multiple RCC cell lines, and could not identify any effect on rapalog sensitivity in in vitro culture assays. We conclude that mTOR pathway gene mutations did not contribute to rapalog resistance development in these six patients with advanced RCC. Furthermore, mechanisms of resistance to rapalogs in RCC remain unclear and our results suggest that PBRM1 loss may contribute to sensitivity through complex transcriptional effects.

Characterization of Patients With Poor-Risk Metastatic Renal-Cell Carcinoma: Results From a Pooled Clinical Trials Database

Background Poor‐risk patients with metastatic renal‐cell carcinoma remain poorly characterized in prospective clinical trials. Therefore, we sought to provide a comprehensive analysis of this patient population, defined by 3 widely used prognostic models, treated with targeted therapy. Patients and Methods We conducted a pooled retrospective analysis of 4736 metastatic renal‐cell carcinoma patients treated on phase 2 and 3 clinical trials. Poor‐risk patients were defined according to the Memorial Sloan Kettering Cancer Center (MSKCC), International Metastatic Renal Cell Carcinoma Database Consortium (IMDC), and Hudes risk models. Baseline characteristics, overall survival, progression‐free survival, objective response rate, and adverse events were reported in poor‐risk patients defined by each of the 3 models. The concordance (C)‐index was used to assess the prognostic performance of the models. A subset of poor‐risk patients who continued to receive treatment for > 12 months was characterized. Results Overall, we identified 1145 (24%), 904 (19%), and 1901 (40%) poor‐risk patients by the IMDC, MSKCC, and Hudes models, respectively. Median overall survival was 8.5 months, 7.5 months, and 10.6 months; and median progression‐free survival was 3.7 months, 3.5 months, and 4.2 months in the IMDC, MSKCC, and Hudes models, respectively. The objective response rate ranged between 10% and 14%. Additionally, 9% to 14% of poor‐risk patients continued to receive treatment for > 12 months. Most importantly, the C‐index was 0.826, 0.830, and 0.825 in the IMDC, MSKCC, and Hudes risk models, respectively. Conclusion We demonstrate that poor‐risk patients continue to have dismal outcomes and warrant alternative treatment strategies to help improve outcomes. A subset of patients experienced prolonged clinical benefit and should be further explored. Micro‐Abstract Given limited prospective clinical trial data of poor‐risk patients with metastatic renal‐cell carcinoma, we sought to provide a comprehensive analysis of this patient population, defined by 3 widely used prognostic models, in the setting of targeted therapy. Our results indicate that the International Metastatic Renal Cell Carcinoma Database Consortium, Memorial Sloan Kettering Cancer Center, and Hudes risk models have comparable discriminative ability. We also show that a subset of poor‐risk patients experiences a prolonged clinical benefit and needs to be further explored.