The tumor microenvironment in renal cell cancer.

PURPOSE OF REVIEW: In addition to the provision of nutrients and growth factors that facilitate tumor cell proliferation and metastasis, the tumor microenvironment (MEV) restricts immune surveillance of tumor-associated antigens and limits the efficacy of immune checkpoint inhibitors, tumor vaccines, and other immune therapies. This review will focus on the immunosuppressive mechanisms operative within the tumor MVE of renal cell carcinoma. RECENT FINDINGS: Several of the immunosuppressive mechanisms within the tumor MEV have been identified and are potentially druggable. Clinical trials with agents that target several of these inhibitory pathways are currently underway. SUMMARY: Although renal cell carcinoma is one of several tumor types responsive to immune checkpoint inhibitors, the effectiveness of these agents is likely to be limited by the various tumor-infiltrating bone marrow-derived myeloid cells that comprise the MEV. Several strategies to combat the recruitment of these cells into tumor tissue or to neutralize their immunosuppressive function have shown encouraging results in animal tumor models and clinical trials.

Sunitinib activates Axl signaling in renal cell cancer.

Mass spectrometry-based phosphoproteomics provides a unique unbiased approach to evaluate signaling network in cancer cells. The tyrosine kinase inhibitor sunitinib is registered as treatment for patients with renal cell cancer (RCC). We investigated the effect of sunitinib on tyrosine phosphorylation in RCC tumor cells to get more insight in its mechanism of action and thereby to find potential leads for combination treatment strategies. Sunitinib inhibitory concentrations of proliferation (IC50) of 786-O, 769-p and A498 RCC cells were determined by MTT-assays. Global tyrosine phosphorylation was measured by LC-MS/MS after immunoprecipitation with the antiphosphotyrosine antibody p-TYR-100. Phosphoproteomic profiling of 786-O cells yielded 1519 phosphopeptides, corresponding to 675 unique proteins including 57 different phosphorylated protein kinases. Compared to control, incubation with sunitinib at its IC50 of 2 µM resulted in downregulation of 86 phosphopeptides including CDK5, DYRK3, DYRK4, G6PD, PKM and LDH-A, while 94 phosphopeptides including Axl, FAK, EPHA2 and p38α were upregulated. Axl- (y702), FAK- (y576) and p38α (y182) upregulation was confirmed by Western Blot in 786-O and A498 cells. Subsequent proliferation assays revealed that inhibition of Axl with a small molecule inhibitor (R428) sensitized 786-O RCC cells and immortalized endothelial cells to sunitinib up to 3 fold. In conclusion, incubation with sunitinib of RCC cells causes significant upregulation of multiple phosphopeptides including Axl. Simultaneous inhibition of Axl improves the antitumor activity of sunitinib. We envision that evaluation of phosphoproteomic changes by TKI treatment enables identification of new targets for combination treatment strategies.

A Phase I Trial of Bortezomib and Sorafenib in Advanced Malignant Melanoma.

LESSONS LEARNED: This study is a rare example of effective doses of both targeted agents being both administered and tolerated.This combination should not be used in melanoma. BACKGROUND: Sorafenib and bortezomib affect BCL family member expression. We previously demonstrated that bortezomib augmented sorafenib-mediated cytotoxicity in melanoma cell lines in vitro. We aimed to combine sorafenib 400 mg b.i.d. with increasing doses of weekly bortezomib. METHODS: Patients with metastatic melanoma were enrolled in dose-escalation cohorts to determine the maximum tolerated dose (MTD) of sorafenib (twice daily) in combination with bortezomib (weekly for 3 of 4 weeks). The MTD was defined as the highest dose level at which less than 33% of patients exhibited a dose-limiting toxicity (DLT). Efficacy, as measured by 6-month progression-free survival and response rate per RECIST, was documented. RESULTS: Eleven patients were enrolled at three dose levels. DLTs (fatigue and rash) were seen in two of three patients at the highest dose level. Five patients were enrolled for sorafenib 400 mg b.i.d. and bortezomib 1.0 mg/m(2) weekly for 3 of every 4 weeks; none had DLTs, and this dose level was defined as the MTD. Of 10 evaluable patients, no responses were seen. Two of 11 patients (18%) remained progression free for longer than 6 months. CONCLUSION: The combination of sorafenib and bortezomib is safe but not active in patients with melanoma.

Predictive biomarkers in renal cell cancer: insights in drug resistance mechanisms.

INTRODUCTION: VEGF-targeted therapy is currently the first line treatment for patients with metastatic clear cell renal cell carcinoma (ccRCC), but most patients either display primary (intrinsic) resistance or acquire drug resistance. In recent years multiple mechanisms of resistance to VEGF-targeted therapy emerged from preclinical research, but it is currently unknown to what extent these drug resistance modalities play a role in the clinic. Here we reviewed the current literature on biomarkers that predict treatment outcome in patients with ccRCC to gain insight in clinical drug resistance mechanisms. METHODS: A search syntax was compiled by combining different synonyms of "biomarker" AND "renal" AND "cancer". MEDLINE was accessed through PubMed, where this syntax was entered and used to search titles and abstracts of publications. Articles were selected based on three criteria: (1) description of patients with clear cell RCC, (2) treatment with VEGF targeted therapy and (3) discussion of biomarkers that were studied for potential association with treatment response. RESULTS: The literature search was performed on March 4th 2014 and yielded 1882 articles. After carefully reading the titles and abstracts based on the three previously mentioned criteria, 103 publications were evaluated. Backward citation screening was performed on all eligible studies and revealed another 24 articles. This search revealed that (1) High glucose uptake and low contrast enhancement on PET- and CT-imaging before start of treatment may correlate with poor response to therapy, (2) Low dose intensity due to treatment intolerance is related to shorter progression free survival. (3) Acquired resistance appears to be associated with rebound vascularization based on both longitudinal monitoring of contrast enhancement by CT and blood vessel counts in tumor tissue, and (4) Based on plasma cytokine and single nucleotide polymorphism (SNP) studies, interleukin-8, VEGFR-3, FGFR2 and HGF/MET emerged as potential clinical markers for chemoresistance. CONCLUSION: Low dose intensity, specific tumor-imaging techniques and potential biological biomarkers may be predictive for response to VEGF-targeted therapy in ccRCC. Some of these plausible biomarkers may also provide more insight into the underlying mechanisms of resistance such as altered glucose metabolism and rapid rebound vascularization.

PI3K inhibition potentiates Bcl-2-dependent apoptosis in renal carcinoma cells.

Inhibitors of PI3-K/Akt are currently being assessed clinically in patients with advanced RCC. Identification of therapeutic strategies that might enhance the efficacy of PI3-K/Akt inhibitors is therefore of great interest. As PI3-K inhibition would be expected to have many pro-apoptotic effects, we hypothesized that there may be unique synergy between PI3-K inhibitors and BH3-mimetics. Towards this end, we assessed the combination of the PI3K inhibitor LY 294002 and the Bcl-2 family inhibitor ABT-737 in RCC cell lines. We found that the combinatorial treatment with these agents led to a significant increase in PARP cleavage and cell death in all RCC cell lines. The synergized cell death was correlated with decreased levels of Mcl-1 and XIAP, and increased levels in Bim, and appears critically dependent upon the activation of caspase 3 and 8. The enhanced lethality observed with the combination also appears dependent upon the regulation of XIAP, Mcl-1 and Bim levels. Our results suggest that the combination of PI3-K inhibitors with BH3-mimetics may be a viable therapeutic strategy in RCC.

Effects of HDM2 antagonism on sunitinib resistance, p53 activation, SDF-1 induction, and tumor infiltration by CD11b+/Gr-1+ myeloid derived suppressor cells.

BACKGROUND: The studies reported herein were undertaken to determine if the angiostatic function of p53 could be exploited as an adjunct to VEGF-targeted therapy in the treatment of renal cell carcinoma (RCC). METHODS: Nude/beige mice bearing human RCC xenografts were treated with various combinations of sunitinib and the HDM2 antagonist MI-319. Tumors were excised at various time points before and during treatment and analyzed by western blot and IHC for evidence of p53 activation and function. RESULTS: Sunitinib treatment increased p53 levels in RCC xenografts and transiently induced the expression of p21(waf1), Noxa, and HDM2, the levels of which subsequently declined to baseline (or undetectable) with the emergence of sunitinib resistance. The development of resistance and the suppression of p53-dependent gene expression temporally correlated with the induction of the p53 antagonist HDMX. The concurrent administration of MI-319 markedly increased the antitumor and anti-angiogenic activities of sunitinib and led to sustained p53-dependent gene expression. It also suppressed the expression of the chemokine SDF-1 (CXCL12) and the influx of CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSC) otherwise induced by sunitinib. Although p53 knockdown markedly reduced the production of the angiostatic peptide endostatin, the production of endostatin was not augmented by MI-319 treatment. CONCLUSIONS: The evasion of p53 function (possibly through the expression of HDMX) is an essential element in the development of resistance to VEGF-targeted therapy in RCC. The maintenance of p53 function through the concurrent administration of an HDM2 antagonist is an effective means of delaying or preventing the development of resistance.

Differential modulatory effects of GSK-3ß and HDM2 on sorafenib-induced AIF nuclear translocation (programmed necrosis) in melanoma.

BACKGROUND: GSK-3ß phosphorylates numerous substrates that govern cell survival. It phosphorylates p53, for example, and induces its nuclear export, HDM2-dependent ubiquitination, and proteasomal degradation. GSK-3ß can either enhance or inhibit programmed cell death, depending on the nature of the pro-apoptotic stimulus. We previously showed that the multikinase inhibitor sorafenib activated GSK-3ß and that this activation attenuated the cytotoxic effects of the drug in various BRAF-mutant melanoma cell lines. In this report, we describe the results of studies exploring the effects of GSK-3ß on the cytotoxicity and antitumor activity of sorafenib combined with the HDM2 antagonist MI-319. RESULTS: MI-319 alone increased p53 levels and p53-dependent gene expression in melanoma cells but did not induce programmed cell death. Its cytotoxicity, however, was augmented in some melanoma cell lines by the addition of sorafenib. In responsive cell lines, the MI-319/sorafenib combination induced the disappearance of p53 from the nucleus, the down modulation of Bcl-2 and Bcl-xL, the translocation of p53 to the mitochondria and that of AIF to the nuclei. These events were all GSK-3ß-dependent in that they were blocked with a GSK-3ß shRNA and facilitated in otherwise unresponsive melanoma cell lines by the introduction of a constitutively active form of the kinase (GSK-3ß-S9A). These modulatory effects of GSK-3ß on the activities of the sorafenib/MI-319 combination were the exact reverse of its effects on the activities of sorafenib alone, which induced the down modulation of Bcl-2 and Bcl-xL and the nuclear translocation of AIF only in cells in which GSK-3ß activity was either down modulated or constitutively low. In A375 xenografts, the antitumor effects of sorafenib and MI-319 were additive and associated with the down modulation of Bcl-2 and Bcl-xL, the nuclear translocation of AIF, and increased suppression of tumor angiogenesis. CONCLUSIONS: Our data demonstrate a complex partnership between GSK-3ß and HDM2 in the regulation of p53 function in the nucleus and mitochondria. The data suggest that the ability of sorafenib to activate GSK-3ß and alter the intracellular distribution of p53 may be exploitable as an adjunct to agents that prevent the HDM2-dependent degradation of p53 in the treatment of melanoma.

High dose intermittent sorafenib shows improved efficacy over conventional continuous dose in renal cell carcinoma.

BACKGROUND: Renal cell carcinoma (RCC) responds to agents that inhibit vascular endothelial growth factor (VEGF) pathway. Sorafenib, a multikinase inhibitor of VEGF receptor, is effective at producing tumor responses and delaying median progression free survival in patients with cytokine refractory RCC. However, resistance to therapy develops at a median of 5 months. In an effort to increase efficacy, we studied the effects of increased sorafenib dose and intermittent scheduling in a murine RCC xenograft model. METHODS: Mice bearing xenografts derived from the 786-O RCC cell line were treated with sorafenib according to multiple doses and schedules: 1) Conventional dose (CD) continuous therapy; 2) high dose (HD) intermittent therapy, 3) CD intermittent therapy and 4) HD continuous therapy. Tumor diameter was measured daily. Microvessel density was assessed after 3 days to determine the early effects of therapy, and tumor perfusion was assessed serially by arterial spin labeled (ASL) MRI at day 0, 3, 7 and 10. RESULTS: Tumors that were treated with HD sorafenib exhibited slowed tumor growth as compared to CD using either schedule. HD intermittent therapy was superior to CD continous therapy, even though the total dose of sorafenib was essentially equivalent, and not significantly different than HD continuous therapy. The tumors exposed to HD sorafenib had lower microvessel density than the untreated or the CD groups. ASL MRI showed that tumor perfusion was reduced to a greater extent with the HD sorafenib at day 3 and at all time points thereafter relative to CD therapy. Further the intermittent schedule appeared to maintain RCC sensitivity to sorafenib as determined by changes in tumor perfusion. CONCLUSIONS: A modification of the sorafenib dosing schedule involving higher dose intermittent treatment appeared to improve its efficacy in this xenograft model relative to conventional dosing. MRI perfusion imaging and histologic analysis suggest that this benefit is related to enhanced and protracted antiangiogenic activity. Thus, better understanding of dosing and schedule issues may lead to improved therapeutic effectiveness of VEGF directed therapy in RCC and possibly other tumors.

Addition of gemcitabine at the time of sunitinib resistance in metastatic renal cell cancer.

OBJECTIVE: •To investigate the role of adding gemcitabine at the time of sunitinib failure in patients with metastatic renal cell cancer (mRCC). PATIENTS AND METHODS: •A retrospective chart review of 13 patients with mRCC who experienced disease progression on sunitinib and received gemcitabine 750 mg/m(2) i.v. on days 1 and 8 and sunitinib 37.5 mg/day on days 2-15 every 21 days from September 2006-2009 was carried out. •Responses were assessed using the Response Evaluation Criteria in Solid Tumors. •The median age was 59, male to female ratio 10:3, Eastern Cooperative Oncology Group performance status 1-3; the number of prior regimens ranged from one to five, and duration on sunitinib alone ranged from 3 months to >1 year. RESULTS: •Twelve out of 13 patients received more than two cycles with one documented partial response, five stable disease and seven progressive disease. •The median time to progression was 21 weeks. •We documented grade 4 pulmonary emboli (n= 1), grade 3 neutropenia (n= 2), anaemia (n= 2) and thrombocytopenia (n= 1). CONCLUSION: •The combination of sunitinib and gemcitabine in patients with mRCC may delay disease progression in some patients exhibiting resistance to sunitinib. This regimen merits further prospective investigation in this patient population.

CXCR4 inhibition modulates the tumor microenvironment and retards the growth of B16-OVA melanoma and Renca tumors.

To determine whether blockade of the chemokine receptor CXCR4 might alter the tumor microenvironment and inhibit tumor growth, we tested the efficacy of the CXCR4 antagonist X4-136 as a single agent and in combination with various immune checkpoint inhibitors in the syngeneic murine melanoma model B16-OVA. We also tested its activity alone and in combination with axitinib in the renal cancer model Renca. We found that X4-136 exhibited potent single agent antitumor activity in the B16-OVA model that was additive to that of an anti-PDL1 antibody. The antitumor activities were associated with a reduction in the number of immunosuppressive regulatory T cells and myeloid-derived suppressor cells and an increase in the number of tumor-specific CD8/perforin cells in the tumor-microenvironment. Apart from these immune effects, X4-136 alone and in combination with checkpoint inhibitors inhibited the Akt/FOXO-3a cell survival pathway in vitro and in vivo, suggesting that it might have antitumor activity independent of its effects on immune cell trafficking. Similar effects on tumor growth and cytotoxic T lymphocytes infiltration were observed in the Renca model. These studies show that the effects of CXCR4 blockade on immune cell trafficking might serve as a useful adjunct to immune checkpoint inhibitors and other therapies in the treatment of cancer.

The role of mammalian target of rapamycin inhibitors in the treatment of advanced renal cancer.

Inhibitors of the mammalian target of rapamycin (mTOR) have shown promising efficacy in early-stage trials in patients with advanced renal cell carcinoma (RCC). Most RCCs have been shown to possess biallelic alterations in the von Hippel-Lindau (VHL) gene, resulting in accumulation of hypoxia-inducible factors 1alpha and 2alpha, as well as their downstream targets including vascular endothelial growth factor (VEGF). The observed clinical efficacy of mTOR inhibitors in patients with RCC may be mediated in part by the dependence of efficient hypoxia-inducible factor translation on the mTOR pathway. mTOR inhibitors have entered more advanced phase clinical trials either as single agents or in combination with other targeted agents or IFN, which might ultimately result in regulatory approval of one or more agents. Given the likely nonoverlapping mechanism of action of mTOR inhibitors and VEGF pathway-targeted agents, mTOR inhibitors may prove useful if administered in combination or after resistance to VEGF inhibitors. With an increasing number of active agents for treatment of patients with RCC, efforts must continue to develop patient selection models based on predictive biomarkers to direct therapy to appropriate patients.

The Raf inhibitor BAY 43-9006 (Sorafenib) induces caspase-independent apoptosis in melanoma cells.

Mitogen-activated protein kinase (MAPK) is activated in the majority of melanomas, and its activity is essential for cell survival. In this report, we examined the effects of a novel raf inhibitor BAY 43-9006 on melanoma cell viability and intracellular signaling and found that it induces apoptosis through a caspase-independent mechanism. At concentrations that suppress extracellular signal-regulated kinase (ERK) phosphorylation, BAY 43-9006 dephosphorylates Bad on Ser(75) and Ser(99), activates Bak and Bax, and reduces the mitochondrial transmembrane potential. BAY 43-9006 (sorafenib) down-modulates the levels of Bcl-2 and Bcl-X(L) in a MAPK-independent manner in A2058 and SKMEL5 melanoma cells but not in the more resistant A375 cells. Of the three lines tested, only A375 cells were rescued from BAY 43-9006-induced apoptosis by knocking down Bad. BAY 43-9006 induced poly(ADP-ribose) polymerase cleavage and the mitochondrial release of cytochrome c and SMAC. However, the pan-caspase inhibitor Z-VAD-fmk had only a modest protective effect against the drug, suggesting that BAY 43-9006-induced apoptosis is largely caspase independent. BAY 43-9006 but not the MAP/ERK kinase inhibitors PD98059 or U0126 induced the nuclear translocation of apoptosis-inducing factor (AIF) in A2058 and SKMEL5 cells, and the introduction of a small interfering RNA (siRNA) for AIF partially protected these cells from BAY 43-9006-induced apoptosis. The AIF siRNA had little effect in A375 cells, in which drug-induced AIF release was negligible. These data indicate that in sensitive cell lines, BAY 43-9006-induced apoptosis is independent of Bad dephosphorylation and caspase activation and largely mediated through the nuclear translocation of AIF.

First-in-Class ERK1/2 Inhibitor Ulixertinib (BVD-523) in Patients with MAPK Mutant Advanced Solid Tumors: Results of a Phase I Dose-Escalation and Expansion Study.

Ulixertinib (BVD-523) is an ERK1/2 kinase inhibitor with potent preclinical activity in BRAF- and RAS-mutant cell lines. In this multicenter phase I trial (NCT01781429), 135 patients were enrolled to an accelerated 3 + 3 dose-escalation cohort and six distinct dose-expansion cohorts. Dose escalation included 27 patients, dosed from 10 to 900 mg twice daily and established the recommended phase II dose (RP2D) of 600 mg twice daily. Ulixertinib exposure was dose proportional to the RP2D, which provided near-complete inhibition of ERK activity in whole blood. In the 108-patient expansion cohort, 32% of patients required dose reduction. The most common treatment-related adverse events were diarrhea (48%), fatigue (42%), nausea (41%), and dermatitis acneiform (31%). Partial responses were seen in 3 of 18 (17%) patients dosed at or above maximum tolerated dose and in 11 of 81 (14%) evaluable patients in dose expansion. Responses occurred in patients with NRAS-, BRAF V600-, and non-V600 BRAF-mutant solid tumors.Significance: Here, we describe the first-in-human dose-escalation study of an ERK1/2 inhibitor for the treatment of patients with advanced solid tumors. Ulixertinib has an acceptable safety profile with favorable pharmacokinetics and has shown early evidence of clinical activity in NRAS- and BRAF V600- and non-V600-mutant solid-tumor malignancies. Cancer Discov; 8(2); 184-95. ©2017 AACR.See related commentary by Smalley and Smalley, p. 140This article is highlighted in the In This Issue feature, p. 127.

Overexpression of kinase suppressor of Ras upregulates the high-molecular-weight tropomyosin isoforms in ras-transformed NIH 3T3 fibroblasts.

The down-regulation of the high-molecular-weight isoforms of tropomyosin (TM) is considered to be an essential event in cellular transformation. In ras-transformed fibroblasts, the suppression of TM is dependent on the activity of the Raf-1 kinase; however, the requirement for other downstream effectors of Ras, such as MEK and ERK, is less clear. In this study, we have utilized the mitogen-activated protein kinase scaffolding protein Kinase Suppressor of Ras (KSR) to further investigate the regulation of TM and to clarify the importance of MEK/ERK signaling in this process. Here, we report that overexpression of wild-type KSR1 in ras-transformed fibroblasts restores TM expression and induces cell flattening and stress fiber formation. Moreover, we find that the transcriptional activity of a TM-alpha promoter is decreased in ras-transformed cells and that the restoration of TM by KSR1 coincides with increased transcription from this promoter. Although ERK activity was suppressed in cells overexpressing KSR1, ERK inhibition alone was insufficient to upregulate TM expression. The KSR1-mediated effects on stress fiber formation and TM transcription required the activity of the ROCK kinase, because these effects could be suppressed by the ROCK inhibitor, Y27632. Overexpression of KSR1 did not directly regulate ROCK activity, but did permit the recoupling of ROCK to the actin polymerization machinery. Finally, all of the KSR1-induced effects were mediated by the C-terminal domain of KSR1 and were dependent on the KSR-MEK interaction.

Targeting the mitogen-activated protein kinase pathway in the treatment of malignant melanoma.

The mitogen-activated protein kinase (MAPK; i.e., Ras-Raf-Erk) pathway is an attractive target for therapeutic intervention in melanoma due to its integral role in the regulation of proliferation, invasiveness, and survival and the recent availability of pharmaceutical agents that inhibit the various kinases and GTPases that comprise the pathway. Genetic studies have identified activating mutations in either B-raf or N-ras in most cutaneous melanomas. Other studies have delineated the contribution of autocrine growth factors (e.g., hepatocyte growth factor and fibroblast growth factor) to MAPK activation in melanoma. Still, others have emphasized the consequences of the down-modulation of endogenous raf inhibitors, such as Sprouty family members (e.g., SPRY2) and raf-1 kinase inhibitory protein, in the regulation of the pathway. The diversity of molecular mechanisms used by melanoma cells to ensure the activity of the MAPK pathway attests to its importance in the evolution of the disease and the likelihood that inhibitors of the pathway may prove to be highly effective in melanoma treatment. MAPK inhibition has been shown to result in the dephosphorylation of the proapoptotic Bcl-2 family members Bad and Bim. This process in turn leads to caspase activation and, ultimately, the demise of melanoma cells through the induction of apoptosis. Several recent studies have identified non-mitogen-activated protein/extracellular signal-regulated kinase kinase-binding partners of raf and suggested that the prosurvival effects of raf and the lethality of raf inhibition are mediated through these alternative targets, independent of the MAPK pathway. Other studies have suggested that endothelial cells are the primary targets of raf inhibitors in vivo and that the antitumor effect of these agents are largely attributable to angiogenesis inhibition. This article reviews the genetic and biochemical factors contributing to MAPK activation in melanoma, the mechanisms by which inhibition of the pathway might prove deleterious to tumor cells, and the potential of MAPK inhibitors in the treatment of the disease.

Innovations and challenges in melanoma: summary statement from the first Cambridge conference.

Innovations and Challenges in Melanoma, chaired by Michael Atkins and cochaired by Ulrich Keilholz, John Kirkwood, and Jeffrey Sosman, was held July 15 to 16, 2005, in Cambridge, Massachusetts. The conference brought together leading experts in the fields of cancer research, medical oncology, surgical oncology, anatomic pathology, dermatology, and immunotherapy who wished to advance the field of melanoma treatment by exchanging information and perspectives regarding recent advances and recommendations for further study. The conference proceedings published in this educational supplement to Clinical Cancer Research are intended to provide timely information and recommendations on how genetics, biology, and data information can enhance our understanding of melanoma biology and help inform the use of therapies for this disease.

Clinical and biological effects of recombinant human interleukin-18 administered by intravenous infusion to patients with advanced cancer.

PURPOSE: Interleukin-18 (IL-18) is an immunostimulatory cytokine with antitumor activity in preclinical animal models. A phase I study of recombinant human IL-18 (rhIL-18) was done to determine the toxicity, pharmacokinetics, and biological activities of rhIL-18 in patients with advanced cancer. EXPERIMENTAL DESIGN: Cohorts of patients were given escalating doses of rhIL-18, each administered as a 2-hour i.v. infusion on 5 consecutive days. Toxicities were graded using standard criteria. Serial blood samples were obtained for pharmacokinetic and pharmacodynamic measurements. RESULTS: Twenty-eight patients (21 with renal cell cancer, 6 with melanoma, and 1 with Hodgkin's lymphoma) were given rhIL-18 in doses ranging from 3 to 1,000 microg/kg. Common side effects included chills, fever, nausea, headache, and hypotension. Common laboratory abnormalities included transient, asymptomatic grade 1 to 2 neutropenia, thrombocytopenia, anemia, hypoalbuminemia, hyponatremia, and elevations in liver transaminases. One patient in the 100 microg/kg cohort experienced transient grade 3 hypotension and grade 2 bradycardia during the first infusion of rhIL-18. No other dose-limiting toxicities were observed. Plasma concentrations of rhIL-18 increased with increasing dose, and 2.5-fold accumulation was observed with repeated dosing. Biological effects of rhIL-18 included transient lymphopenia and increased expression of activation antigens on lymphocytes and monocytes. Increases in serum concentrations of IFN-gamma, granulocyte macrophage colony-stimulating factor, IL-18 binding protein, and soluble Fas ligand were observed. Two patients experienced unconfirmed partial responses after rhIL-18 treatment. CONCLUSIONS: rhIL-18 can be safely given in biologically active doses to patients with advanced cancer. A maximum tolerated dose of rhIL-18 was not determined. Further clinical studies of rhIL-18 are warranted.

FCGR Polymorphisms Influence Response to IL2 in Metastatic Renal Cell Carcinoma.

Purpose: Fc-gamma receptors (FCGRs) are expressed on immune cells, bind to antibodies, and trigger antibody-induced cell-mediated antitumor responses when tumor-reactive antibodies are present. The affinity of the FCGR/antibody interaction is variable and dependent upon FCGR polymorphisms. Prior studies of patients with cancer treated with immunotherapy indicate that FCGR polymorphisms can influence antitumor response for certain immunotherapies that act via therapeutically administered mAbs or via endogenous tumor-reactive antibodies induced from tumor antigen vaccines. The previously published "SELECT" trial of high-dose aldesleukin (HD-IL2) for metastatic renal cell carcinoma resulted in an objective response rate of 25%. We evaluated the patients in this SELECT trial to determine whether higher-affinity FCGR polymorphisms are associated with outcome.Experimental Design: SNPs in FCGR2A, FCGR3A, and FCGR2C were analyzed, individually and in combination, for associations between genotype and clinical outcome.Results: When higher-affinity genotypes for FCGR2A, FCGR3A, and FCGR2C were considered together, they were associated with significantly increased tumor shrinkage and prolonged survival in response to HD-IL2.Conclusions: Although associations of higher-affinity FCGR genotype with clinical outcome have been demonstrated with mAb therapy and with idiotype vaccines, to our knowledge, this is the first study to show associations of FCGR genotypes with outcome following HD-IL2 treatment. We hypothesize that endogenous antitumor antibodies may engage immune cells through their FCGRs, and HD-IL2 may enhance antibody-induced tumor destruction, or antibody-enhanced tumor antigen presentation, via augmented activation of innate or adaptive immune responses; this FCGR-mediated immune activity would be augmented through immunologically favorable FCGRs. Clin Cancer Res; 23(9); 2159-68. ©2016 AACR.