Outcomes of patients with metastatic clear-cell renal cell carcinoma treated with second-line VEGFR-TKI after first-line immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are being increasingly utilised in the front-line (1L) setting of metastatic clear-cell renal cell carcinoma (mccRCC). Limited data exist on responses and survival on second-line (2L) vascular endothelial growth factor-receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy after 1L ICI therapy.

PATIENTS AND METHODS

This is a retrospective study of mccRCC patients treated with 2L VEGFR-TKI after progressive disease (PD) with 1L ICI. Patients were treated at MD Anderson Cancer Center or Memorial Sloan Kettering Cancer Center between December 2015 and February 2018. Objective response was assessed by blinded radiologists' review using Response Evaluation Criteria in Solid Tumours v1.1. Descriptive statistics and Kaplan-Meier method were used.

RESULTS

Seventy patients were included in the analysis. Median age at mccRCC diagnosis was 59 years; 8 patients (11%) had international metastatic database consortium favourable-risk disease, 48 (69%) had intermediate-risk disease and 14 (20%) had poor-risk disease. As 1L therapy, 12 patients (17%) received anti-programmed death ligand-1 (PD-(L)1) monotherapy with nivolumab or atezolizumab, 33 (47%) received nivolumab plus ipilimumab and 25 (36%) received combination anti-PD-(L)1 plus bevacizumab. 2L TKI therapies included pazopanib, sunitinib, axitinib and cabozantinib. On 2L TKI therapy, one patient (1.5%) achieved a complete response, 27 patients (39.7%) a partial response and 36 patients (52.9%) stable disease. Median progression-free survival (mPFS) was 13.2 months (95% confidence interval: 10.1, NA). Forty-five percent of subjects required a dose reduction, and twenty-seven percent of patients discontinued treatment because of toxicity.

CONCLUSIONS

In this retrospective study of patients with mccRCC receiving 2L TKI monotherapy after 1L ICI, we observed 2L antitumour activity and tolerance comparable to historical data for 1L TKI.

Cabozantinib for the treatment of patients with metastatic non-clear cell renal cell carcinoma: A retrospective analysis

BACKGROUND

Cabozantinib prolongs overall survival (OS) and progression-free survival (PFS) in patients with metastatic clear cell renal cell carcinoma (RCC) that progressed on first-line vascular endothelial growth factor receptor-tyrosine kinase inhibitor (VEGFR-TKI). The role of cabozantinib has not been established in non-clear cell renal cell carcinoma (nccRCC).

METHODS

This is a retrospective study of 30 patients with nccRCC who received cabozantinib from January 2013 to January 2017. Information collected included baseline characteristics, toxicity, dose reductions, PFS and OS. A fellowship trained abdominal radiologist, blinded to patient history and clinical data, assessed radiographic response using RECIST, v1.1.

RESULTS

With a median follow-up of 20.6 months (95% confidence interval [CI]: 11.4-28.8), median PFS was 8.6 months (95% CI: 6.1-14.7), and median OS was 25.4 months (95% CI: 15.5-35.4). Of the 28 patients with measurable disease, 4 had partial responses (2 papillary, 1 chromophobe and 1 unclassified RCC), 18 had stable disease (64.2%) and 6 had progressive disease (21.4%), resulting in a 14.3% objective response rate and a 78.6% disease control rate. Two patients with papillary RCC who had experienced disease progression on savolitinib achieved durable partial response and stable disease, respectively, following treatment with cabozantinib. Of the 21 patients who started cabozantinib at 60 mg/d, 12 (57.1%) required dose reduction due to toxicity.

CONCLUSION

In this retrospective study, cabozantinib produced a clinically meaningful benefit in patients with metastatic nccRCC, the majority of whom had disease progression on prior VEGFR-TKIs. Prospective trials of cabozantinib in nccRCC are warranted.

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.

Osseous Pseudoprogression in Vertebral Bodies Treated with Stereotactic Radiosurgery: A Secondary Analysis of Prospective Phase I/II Clinical Trials

BACKGROUND AND PURPOSE

Osseous pseudoprogression on MR imaging can mimic true progression in lesions treated with spine stereotactic radiosurgery. Our aim was to describe the prevalence and time course of osseous pseudoprogression to assist radiologists in the assessment of patients after spine stereotactic radiosurgery.

MATERIALS AND METHODS

A secondary analysis of 2 prospective trials was performed. MRIs before and after spine stereotactic radiosurgery were assessed for response. "Osseous pseudoprogression" was defined as transient growth in signal abnormality centered at the lesion with a sustained decline on follow-up MR imaging that was not attributable to chemotherapy.

RESULTS

From the initial set of 223 patients, 37 lesions in 36 patients met the inclusion criteria and were selected for secondary analysis. Five of the 37 lesions (14%) demonstrated osseous pseudoprogression, and 9 demonstrated progressive disease. There was a significant association between single-fraction therapy and the development of osseous pseudoprogression (P = .01), and there was a significant difference in osseous pseudoprogression-free survival between single- and multifraction regimens (P = .005). In lesions demonstrating osseous pseudoprogression, time-to-peak size occurred between 9.7 and 24.4 weeks after spine stereotactic radiosurgery (mean, 13.9 weeks; 95% CI, 8.6-19.1 weeks). The peak lesion size was between 4 and 10 mm larger than baseline. Most lesions returned to baseline size between 23 and 52.4 weeks following spine stereotactic radiosurgery.

CONCLUSIONS

Progression on MR imaging performed between 3 and 6 months following spine stereotactic radiosurgery should be treated with caution because osseous pseudoprogression may be seen in more than one-third of these lesions. Single-fraction spine stereotactic radiosurgery may be associated with osseous pseudoprogression. The possibility of osseous pseudoprogression should be incorporated into the prospective criteria for assessment of local control following spine stereotactic radiosurgery.

High-resolution profiling of histone h3 lysine 36 trimethylation in metastatic renal cell carcinoma

Mutations in SETD2, a histone H3 lysine trimethyltransferase, have been identified in clear cell renal cell carcinoma (ccRCC); however it is unclear if loss of SETD2 function alters the genomic distribution of histone 3 lysine 36 trimethylation (H3K36me3) in ccRCC. Furthermore, published epigenomic profiles are not specific to H3K36me3 or metastatic tumors. To determine if progressive SETD2 and H3K36me3 dysregulation occurs in metastatic tumors, H3K36me3, SETD2 copy number (CN) or SETD2 mRNA abundance was assessed in two independent cohorts: metastatic ccRCC (n=71) and the Cancer Genome Atlas Kidney Renal Clear Cell Carcinoma data set (n=413). Although SETD2 CN loss occurs with high frequency (>90%), H3K36me3 is not significantly impacted by monoallelic loss of SETD2. H3K36me3-positive nuclei were reduced an average of ~20% in primary ccRCC (90% positive nuclei in uninvolved vs 70% positive nuclei in ccRCC) and reduced by ~60% in metastases (90% positive in uninvolved kidney vs 30% positive in metastases) (P<0.001). To define a kidney-specific H3K36me3 profile, we generated genome-wide H3K36me3 profiles from four cytoreductive nephrectomies and SETD2 isogenic renal cell carcinoma (RCC) cell lines using chromatin immunoprecipitation coupled with high-throughput DNA sequencing and RNA sequencing. SETD2 loss of methyltransferase activity leads to regional alterations of H3K36me3 associated with aberrant RNA splicing in a SETD2 mutant RCC and SETD2 knockout cell line. These data suggest that during progression of ccRCC, a decline in H3K36me3 is observed in distant metastases, and regional H3K36me3 alterations influence alternative splicing in ccRCC.

Role of partial nephrectomy as cytoreduction in the management of metastatic renal cell carcinoma

In this review, we describe the role, feasibility and safety of partial nephrectomy in the setting of metastatic renal cell carcinoma. Partial nephrectomy is currently the preferred therapeutic modality in patients with localized renal tumors, while radical cytoreductive nephrectomy is the standard of care for appropriately selected patients with metastatic disease. Several studies have shown the prognostic value of percentage tumor removed when cytoreductive nephrectomy is done. This concept of percentage tumor removal and the associated benefit should also be applied when considering patients for cytoreductive partial nephrectomy; however, the potential adverse events after partial nephrectomy should be kept in mind, as these, when they occur, could delay time to starting systemic therapy. Several small retrospective studies have shown the feasibility of this approach in carefully selected patient groups. In well-selected patients with metastatic disease and primary tumors that are amenable to nephron sparing approaches, partial nephrectomy could offer an alternative to radical nephrectomy, with manageable adverse events, and good renal functional outcomes. Preserving renal function in this population could allow these patients to participate in clinical trial that they otherwise might not qualify for.

Outcomes of patients with metastatic clear-cell renal cell carcinoma treated with pazopanib after disease progression with other targeted therapies

AIM

The multi-tyrosine kinase inhibitor pazopanib prolongs progression-free survival (PFS) versus placebo in treatment-naive and cytokine-refractory metastatic clear-cell renal cell carcinoma (ccRCC). Outcomes and safety data with pazopanib after targeted therapy (TT) are limited.

METHODS

We retrospectively evaluated records of consecutive patients with metastatic ccRCC who had progressive disease (PD) after TT and received pazopanib from November 2009 through November 2011. Tumour response was assessed by a blinded radiologist using Response Evaluation Criteria In Solid Tumours (RECIST). PFS and overall survival (OS) were estimated by Kaplan-Meier methods.

RESULTS

Ninety-three patients were identified. Median number of prior TTs was 2 (range, 1-5). There were 68 events (PD or death). Among 85 evaluable patients, 13 (15%) had a partial response. Median PFS was 6.5 months (95% CI: 4.5-9.7); median OS was 18.1 months (95% CI: 10.26-NA). Common adverse events (AEs) included fatigue (44%), elevated transaminases (35%), diarrhoea (30%), hypothyroidism (18%), nausea/vomiting (17%), anorexia (14%) and hypertension exacerbation (14%); 91% of AEs were grade 1/2. Eleven patients (12%) discontinued therapy due to AEs. There were no treatment-related deaths.

CONCLUDING STATEMENT

Pazopanib demonstrated efficacy in patients with metastatic ccRCC after PD with other TTs. Toxicity overall was mild/moderate and manageable.

Pilot trial of sunitinib therapy in patients with von Hippel-Lindau disease

BACKGROUND

Von Hippel-Lindau (VHL) disease induces vascular neoplasms in multiple organs. We evaluated the safety and efficacy of sunitinib in VHL patients and examined the expression of candidate receptors in archived tissue.

METHODS

Patients with VHL were given four cycles of 50 mg sunitinib daily for 28 days, followed by 14 days off. Primary end point was toxicity. Modified RECIST were used for efficacy assessment. We evaluated 20 archival renal cell carcinomas (RCCs) and 20 hemangioblastomas (HBs) for biomarker expression levels using laser-scanning cytometry (LSC).

RESULTS

Fifteen patients were treated. Grade 3 toxicity included fatigue in five patients. Dose reductions were needed in 10 patients. Eighteen RCC and 21 HB lesions were evaluable. Six of the RCCs (33%) responded partially, versus none of the HBs (P = 0.014). LSC revealed that mean levels of phosphorylated vascular endothelial growth factor receptor-2 were lower in HB than in RCC endothelium (P = 0.003) and mean phosphorylated fibroblast growth factor receptor substrate-2 (pFRS2) levels were higher in HB (P = 0.003).

CONCLUSIONS

Sunitinib treatment in VHL patients showed acceptable toxicity. Significant response was observed in RCC but not in HB. Greater expression of pFRS2 in HB tissue than in RCC raises the hypothesis that treatment with fibroblast growth factor pathway-blocking agents may benefit patients with HB.

A cytokine and angiogenic factor (CAF) analysis in plasma for selection of sorafenib therapy in patients with metastatic renal cell carcinoma

BACKGROUND

We investigated cytokines and angiogenic factors (CAFs) in patients with metastatic renal cell carcinoma (mRCC) treated in a randomized phase II clinical trial of sorafenib versus sorafenib+ interferon-α (IFN-α) that yielded no differences in progression-free survival (PFS). We aimed to link the CAF profile to PFS and select candidate predictive and prognostic markers for further study.

METHODS

The concentrations of 52 plasma CAFs were measured pretreatment (n = 69), day 28, and day 56 using multiplex bead arrays and enzyme-linked immunosorbent assay. We investigated the association between baseline levels of CAFs with PFS and posttreatment changes.

RESULTS

Unsupervised CAF clustering analysis revealed two distinct mRCC patient groups with elevated proangiogenic or proinflammatory mediators. A six-marker baseline CAF signature [osteopontin, vascular endothelial growth factor (VEGF), carbonic anhydrase 9, collagen IV, VEGF receptor-2, and tumor necrosis factor-related apoptosis-inducing ligand] correlated with PFS benefit (hazard ratio 0.20 versus 2.25, signature negative versus positive, respectively; P = 0.0002). While changes in angiogenic factors were frequently attenuated by the sorafenib+ IFN combination, most key immunomodulatory mediators increased.

CONCLUSIONS

Using CAF profiling, we identified two mRCC patient groups, a candidate plasma signature for predicting PFS benefit, and distinct marker changes occurring with each treatment. This platform may provide valuable insights into renal cell carcinoma biology and the molecular consequences of targeted therapies.

Tyrosine kinase inhibitors and development of brain metastasis in metastatic renal cell carcinoma: A retrospective review

340

Background: Tyrosine kinase inhibitors (TKIs) have been shown to improve overall survival (OS) in metastatic renal cell carcinoma (mRCC) but their effect on brain metastasis (BM) development is unclear. The purpose of our study is to evaluate the impact of TKIs on incidence of BM and OS in patients with mRCC.

Methods: Searched the M. D. Anderson Cancer Center (MDACC) tumor registry for patients who presented with mRCC in 2002-2003 and 2006-2007 with no BM at initial staging. The following items were retrospectively collected: age, sex, Fuhrman grade, sites of disease, nephrectomy, systemic therapy including TKIs (sorafenib or sunitinib), MSKCC risk category, BM treatment, and vital status. Interaction between OS and incidence of BM and these variables was estimated using the Cox proportional hazards model. OS and incidence of BM were estimated using the Kaplan-Meier (K-M) method.

Results: 338 patients were identified; 154 (46%) were treated with a TKI prior to BM, and 184 (54%) were not. There were no significant differences in age, histology, involved sites of disease other than lung, nephrectomy, or MSKCC risk category between the groups. A higher proportion of the nonTKI group received other systemic agents and had lung metastasis at initial staging (p=0.03). Median OS was longer in the TKI-treated group (25 months versus 12.1 months, p<0.0001). In Cox multivariate analysis, TKI treatment (HR=0.53, 95% CI 0.38-0.74, p<0.001) was associated with improved OS and lung/mediastinal involvement and ECOG performance status > 2 (HR 1.87, 95% CI 1.28-2.71, p=0.001) were associated with poor OS. Median OS after BM was not significantly different between TKI treated and untreated groups. 44 patients (13%) developed a BM, including 29 (15.8%) of the nonTKI group and 15 (9.7%) of the TKI group. In K-M analysis, the 5-year incidence of BM was 40% versus 17% respectively (logrank p<0.001). In Cox multivariate analysis, TKI treatment was associated with lower incidence of BM (HR=0.39, 95% CI 0.21-0.73, p=0.003). Lung metastasis increased the risk of BM (HR=9.61, 95% CI 2.97-31.1, p<0.001).

Conclusions: Treatment with TKI agents reduces the incidence of BM in mRCC. Lung metastasis is a risk factor for BM development.

No significant financial relationships to disclose.

Everolimus-associated pneumonitis (EAP) in metastatic renal cell cancer patients (mRCC): A single-center experience

332

Background: Pneumonitis is a known adverse effect (AE) of mammalian target of rapamycin-inhibitors, with a literature reported incidence for everolimus ranging from 4 to 45%. The goal of this review was to characterize the incidence, timing, management, and outcomes related to everolimus-associated pneumonitis (EAP).

Methods: Retrospective review of 86 mRCC patients (pts) with complete, evaluable records, given everolimus (E) between 4/2009 and 3/2010. We assessed baseline patient (pt) characteristics, previous therapies, time on E therapy, pt symptoms, physician management of AE, NCI-CTC pneumonitis grading, and survival outcomes. Radiologic CT indicated ground glass, inflammatory, and/or parenchymal opacities.

Results: (See table.) EAP occurred in 28% of pts on E therapy, confirmed radiologically. 8% of EAP patients reported no symptoms. In EAP pts, 58% reported cough, 75% dyspnea and/or SOB, 17% fever, 71% fatigue. The median number of symptoms/patient was 3. 46% of pts received steroids (median 21 days (3-120)), 38% received antibiotics, 25% received pulmonary consultation, and 8% required oxygen. In pts who developed EAP, providers discontinued E in 75%, held and dose reduced E in 8%, and continued E in 17%. The median NCI-CTC pneumonitis grade was 2 (1-3); there were no treatment-related deaths. The median time to EAP onset was 67 days (8-442). There was no statistically significant difference in outcomes between EAP pts and non-EAP pts.

Conclusions: EAP occurs often in mRCC pts treated with E. It is an important AE that can negatively affect pt symptoms, but did not adversely impact pt outcomes in our single-center experience.

[Table: see text]

[Table: see text]

Use of early primary tumor response to predict overall survival in patients with metastatic RCC undergoing treatment with sunitinib

329

Background: In metastatic renal cell carcinoma (mRCC) patients treated with sunitinib and the primary tumor in situ, there is minimal predictive data available to help guide clinicians during treatment with targeted therapy. In prior studies, early primary tumor response (PTR) was associated with improved overall PTR, but the effect on overall survival (OS) is unknown. The purpose of our study was to evaluate whether early PTR was associated with improved OS in mRCC patients undergoing treatment with sunitinib.

Methods: We reviewed our institutional database to identify patients with mRCC treated with sunitinib with primary tumor in situ. Clinical and pathological data were collected for each patient. Sequential abdominal CT or MRI scans were reviewed to evaluate PTR. Early PTR was defined as ≥ 10% decrease in tumor diameter within the first 90 days of treatment. Univariable and multivariable stepwise Cox proportional hazards regression analysis were performed to identify predictors of OS in these patients.

Results: 75 consecutive patients were identified between 2005 and 2009 with a median follow-up of 15 months. 24 patients exhibited an early PTR; median maximum response 23.1% (range: −53.4, −10.2) and decrease in primary tumor diameter at a median of 90.5 days. Early PTR was associated with a decreased risk of death on multivariate analysis (HR: 0.18; 95% CI 0.05, 0.62, p<0.01). In addition, median OS was improved in patients with an early PTR (30.2 vs. 12.7 months). Independent predictors of decreased survival on multivariate analysis included local symptoms, multiple bone metastases, clinical evidence of venous thrombus, LDH > upper limit of normal, and >2 visceral metastatic sites.

Conclusions: Early PTR ≥ 10% is associated with improved survival, better response in metastatic sites, and better overall PTR in patients with mRCC. Future studies should consider this variable when evaluating sunitinib in mRCC treatment.

[Table: see text]

Long-term survival of patients with metastatic renal cell carcinoma (mRCC) treated with targeted therapy (TT) without cytoreductive nephrectomy (CN)

346

Background: We recently reported on 188 patients (pts) with mRCC treated with TT without CN [Richey et al, J Clin Oncol 28:15s, 2010 (suppl; abstr 4613); Annals of Oncology- in press]. We report here outcome data on pts who survived > 24 months (mos).

Methods: We retrospectively reviewed records of patients with mRCC who received TT without CN and survived longer than 24 mos from treatment initiation. Pts did not undergo CN due to medical comorbidity, unresectable primary tumor, heavy disease burden, or patient preference. Kaplan-Meier methods were used to estimate median overall survival (OS). Long-term complications related to therapy were evaluated.

Results: 22 pts were identified meeting the inclusion criteria. Median follow-up was 30.4 mos (range, 24.1- 68.7), with median OS time of 34.1 mos (95% CI: 30.2, 37.2). Median time on therapy (TOT) was 25.3 mos (IQR: 13.7, 28.5). Six pts (27.3%) were alive at the time of analysis, with median TOT of 26.9 mos (range: 13.7, 62.5) (IQR: 24.6, 33.4). Eastern Cooperative Oncology Group performance status was 0 or 1 in 86% of pts. Ten (45%) and 12 (55%) pts had intermediate- and poor-risk disease by Heng et al criteria (JCO 2009), respectively. Patients received the following types of TT: sunitinib 14 (63.6%), sorafenib 13 (59.1%), temsirolimus 5 (22.7%), bevacizumab 5 (22.7%), pazopanib 3 (13.6%), everolimus 4 (18.2%), erlotinib 3 (13.6%), investigational targeted agent 1 (4.6%). Four (18.2%), 5 (22.7%), and 13 (59.1%) pts received 1, 2, or ≥ 3 different therapies, respectively. During treatment with TT, 6 pts (27.3%) developed hypertension, 6 pts (27.3%) developed hypothyroidism, 2 pts (9.1%) developed congestive heart failure, 1 pt (4.6%) developed stroke. No pts developed bleeding or myocardial infarction. By radiographic assessment of best primary tumor response, 4 (18.2%) pts had a partial response (≥30% decrease), 10 (45.5%) exhibited a decrease <30%, and 6 (27.3%) had stable or increased size of the primary tumor.

Conclusions: These data highlight the potential for long-term survival of patients with mRCC treated with TT without CN, and underscore the challenges in managing therapy-related long-term adverse events.

No significant financial relationships to disclose.

AMG 386 in combination with sorafenib in patients (pts) with metastatic renal cell cancer (mRCC): A randomized, double-blind, placebo-controlled, phase II study

309

Background: AMG 386 inhibits angiogenesis by sequestering angiopoietin-1 and -2, thus preventing their interaction with the Tie2 receptor on endothelial cells. Combination with VEGF receptor inhibition has demonstrated additive effects in vivo. The efficacy and tolerability of sorafenib plus AMG 386, an investigational peptide-Fc fusion protein, were evaluated in mRCC pts.

Methods: Treatment-naive pts with clear cell mRCC were randomized 1:1:1 to sorafenib 400 mgPO BID plus AMG 386 10 mg/kg (Arm A) or 3 mg/kg (Arm B) QW; or placebo (Arm C) IV QW. Endpoints were progression-free survival (PFS; primary); and (secondary) objective response rate (ORR), change in tumor burden, adverse events (AEs) and pharmacokinetics. Tumor assessment was performed at baseline and every 8 weeks thereafter.

Results: 152 pts were randomized: Arms A/B/C, n=50/51/51. 60/61/61% of pts had intermediate and 40/39/37% had low MSKCC risk at baseline. PFS was similar in all 3 arms, whereas ORR was higher in the AMG 386 arms ( Table ). In Arms A/B/C the incidence of grade ≥ 3 AEs was 66/73/86% and serious AEs 36/49/28%. The most common AEs included diarrhea (70/67/56%; grade ≥3 8/10/8%), hand- foot syndrome (52/47/54%; grade ≥3 12/16/28%), alopecia (50/45/50%; grade ≥3 0/0/2%), and hypertension (42/49/46%; grade ≥3 18/20/14%). Median steady-state Cmax and Cmin for AMG 386 were similar to those reported previously. Sorafenib coadministration did not markedly affect AMG 386 exposure.

Conclusions: Sorafenib plus AMG 386 was tolerable but did not improve PFS compared with sorafenib plus placebo. Increased ORR and the observed reduction in tumor burden are suggestive of an antitumor effect of AMG 386 in mRCC.

[Table: see text]

[Table: see text]

Metastatic renal cell carcinoma treated with pazopanib after progression on other targeted agents: A single-institution experience

351

Background: Pazopanib, a multityrosine kinase inhibitor (TKI), prolongs PFS compared to placebo in treatment-naive and cytokine refractory metastatic renal cell carcinoma (mRCC). No data has been reported about pazopanib salvage therapy after treatment with other targeted agents.

Methods: We retrospectively reviewed the records of 88 consecutive patients (pts) with mRCC (median age 62.7, M:F 63/25, 84% clear cell) who received salvage pazopanib between 11/09-8/10. All pts failed previous treatment with one or more targeted agents (median number of prior targeted agents was 2, range 1-5; median time on previous treatments was 632 days). 78% of pts had progressed on sunitinib, 40% on sorafenib, 20% on temsirolimus, 51% on everolimus, and 26% on bevacizumab. 26% received previous chemotherapy and 16% received previous cytokines in addition to targeted therapies. 58% failed both TKI/VEGF inhibitors and mTOR inhibitors. 57% had intermediate-risk disease and 43% had poor-risk disease by MSKCC criteria. All pts had follow-up at least every 3 months after initiating pazopanib.

Results: Median time to last follow-up was 114 days (range 30-278 days). 42% continued pazopanib at last follow- up. 25% had partial response (PR) by treating physician assessment. 50% failing 1-2 previous targeted therapies remained on pazopanib at last follow-up, compared to 27% of those failing more than 2 targeted therapies (p=0.04). 56% of pts with intermediate-risk disease by MSKCC criteria continued pazopanib at follow-up compared to 27% with poor-risk disease (p=0.002). 42% of those failing 1 prior targeted therapy achieved PR compared to 18% failing >1 prior targeted therapy (p=0.02). 35% discontinued pazopanib due to progressive disease (PD) (median time to PD 71 days, range 36-198 days), 10% discontinued due to adverse drug events, and 10% died of PD on treatment. There were no treatment related deaths.

Conclusions: In this retrospective study, pazopanib demonstrated clinically relevant activity in mRCC following PD with other targeted therapies. Mature survival data will be provided with final presentation.

No significant financial relationships to disclose.

Chromosome 14q imbalances and pathways associated with resistance to antiangiogenic therapy in clear cell renal cell carcinoma

339

Background: Antiangiogenic agents are used to treat metastatic clear cell renal cell carcinoma (ccRCC). Currently there are no biomarkers of therapeutic efficacy for these agents. Hypoxia inducible factor (HIF) alpha ratios have been linked to phenotypically distinct ccRCC subpopulations. The HIF1 alpha gene is located on chromosome 14q. In this study, the goal was to determine whether chromosomal imbalances identified with SNP arrays are linked to HIF ratios, and to clinical outcome.

Methods: We obtained archival FFPE tumor specimens from 56 patients with mRCC treated with sorafenib or bevacizumab. DNA from the FFPE blocks was analyzed with Affymetrix 250K Nsp SNP microarrays. We identified the presence of genomic imbalances and loss of heterozygosity (LOH) to obtain virtual karyotypes. We then evaluated candidate genes in gain/lost chromosomal regions by qPCR and immunohistochemistry (IHC) in the bevacizumab treated specimens.

Results: In the bevacizumab cohort, HIF1-alpha containing14q loss showed a significant association with worse response to treatment (CR/ PR vs. SD/PD, Fisher exact test, p = 0.0473). In addition, HIF1A mRNA expression was significantly reduced in all samples with 14q loss and was associated with PFS (HR = 2.29, 95% CI = 1.01-5.16, p = 0.045). HIF-1alpha protein expression was also reduced in samples with 14q loss.

Conclusions: Chromosomal imbalances are associated with outcomes in ccRCC patients treated with antiangiogenic agents, and can lead to changes in gene expression. Low HIF1A expression was strongly correlated with shorter PFS. We hypothesize that loss of 14q could lead to an imbalance in HIF-1alpha/HIF-2alpha activity, leading to increased HIF-2alpha and enhanced c-Myc expression, which improves tumor cell viability and engenders resistance to cellular stress induced by antiangiogenic therapy.

No significant financial relationships to disclose.

Outcome of patients (pts) with renal medullary carcinoma (RMC) treated in the era of targeted therapies (TT): A multicenter experience

386

Background: RMC is a rare, highly aggressive primary neoplasm of the kidney that almost exclusively afflicts young black pts with sickle cell hemoglobinopathies, primarily sickle cell trait. The primary objectives of this study were to evaluate the clinical characteristics and treatment outcome of RMC pts.

Methods: We retrospectively reviewed the medical records of pts diagnosed with RMC at four US institutions between 2000 and 2010. Overall survival (OS) was determined from initial diagnosis to date of death or last follow up (F/U). The time interval from date of metastasis to death or last F/U (OSm) was also determined. Kaplan-Meier methods were used to estimate OS and OSm.

Results: 20 RMC pts were identified. All pts were black; 14 (70%) were males; 18 had sickle cell trait, 1 had sickle thalassemia and 1 not tested. 19 presented with stages III or IV; 7 (35%) had nephrectomy. Nineteen pts had ≥ 2 metastatic sites. Twelve pts had performance status [PS] 0/1; eight pts had PS 2/3. For the OS analysis, data on 16 pts were available and for the OSm analysis, data on 20 pts were available. The median follow up time for the OS analysis was 722 days. Thirteen of 16 pts died with median OS of 421 days [95%CI: 225–546]. Sixteen of 20 pts died in the OSm analysis with median OSm of 378 days [95%CI: 225–487]. Frontline therapy consisted of TT [sunitinib (5), bevacizumab + erlotinib (1), imatinib (2)], chemotherapy (C) [platinum/gemcitabine or taxane (7), gemcitabine/doxorubicin (2)], C + TT [gemcitabine/cisplatinum/bevacizumab (2), imatinib/doxorubicin (1)]. Three pts achieved a partial response (PR) in first-line (2 with C, 1 with C + TT). Twelve pts received second-line systemic therapies; 4 achieved PR (1 with bevacizumab/erlotinib, 2 with C, 1 with C + TT). Among 15 pts who had TT at any time during their treatment course, only 1 pt had PR.

Conclusions: The prognosis of RMC pts remains poor despite initial palliation with systemic therapy. Collaborative multi-institutional efforts are needed to better understand the biology of this disease and improve treatment strategies.

No significant financial relationships to disclose.

Outcome of patients with metastatic renal cell carcinoma treated with targeted therapy without cytoreductive nephrectomy

BACKGROUND

Cytoreductive nephrectomy (CN) became a standard procedure in metastatic renal cell carcinoma (mRCC) in the immunotherapy era. Historically, median overall survival (OS) of patients treated with interferon alpha (IFN-α) without CN was 7.8 months. Median OS in patients treated with targeted therapy (TT) without CN is unknown.

PATIENTS AND METHODS

We retrospectively reviewed records of patients with mRCC who received TT without CN. Kaplan-Meier methods and Cox regression analysis were used to estimate median OS and identify poor prognostic factors.

RESULTS

One hundred and eighty-eight patients were identified. Most patients had intermediate-risk (54.8%) or poor-risk (44.1%) disease. Median OS for all patients was 10.4 months [95% confidence interval (CI) 8.1-12.5]. By multivariable analysis, elevated baseline lactate dehydrogenase and corrected calcium, performance status of two or more, retroperitoneal nodal metastasis, thrombocytosis, current smoking, two or more metastatic sites, and lymphopenia were independent risk factors for inferior OS. Patients with four or more factors had increased risk of death (hazard ratio 8.83, 95% CI 5.02-15.5, P < 0.001) and 5.5-month median OS. Nineteen patients (10.0%) survived for 2+ years.

CONCLUSIONS

These data highlight the improved OS of patients with mRCC treated with TT without CN, compared with historical IFN-α treatment, and may guide the design of trials investigating the role of CN in the TT era.

A cytokine and angiogenic factor (CAF) plasma signature for selection of sorafenib (SR) therapy in patients (pts) with metastatic renal cell carcinoma (mRCC)

5114

Background: SR, an oral inhibitor of Raf kinase, RET-receptor (R), VEGFR-1, 2, and 3, PDGFR-β, FLT-3, and c-KIT tyrosine kinases, has been shown to prolong progression-free survival (PFS) in mRCC after cytokine failure. In a phase II trial, mRCC pts were randomized to first line treatment with SR vs. SR plus interferon (IFN) to assess whether combination therapy improved PFS. Both treatment arms showed similar outcomes (Tannir et al, ASCO. 2008). Here we investigated predictive and prognostic biomarkers in plasma. Methods: Pts received SR 400 mg PO BID or same dose SR plus IFN 0.5 MU SC BID. Plasma was collected from 69 pts at baseline (BL; SR 34, SR+IFN 35), 59 on day (D) 28, and 57 pts on D56. We used multiplex bead suspension arrays to measure concentrations of 54 CAFs, including VEGF, PDGFbb, EGF, HGF, MMP-9, and multiple chemokines and interleukins (IL). Osteopontin (OPN), soluble carbonic anhydrase 9 (sCA9), placental growth factor (PlGF), collagen type IV (ColIV) and sVEGFR-2 were measured by ELISA. The primary objective of this analysis was to establish a CAF signature based on a set of individual markers at BL with a significant and differential impact on the association between treatment arm and PFS. Results: Among 52 CAFs available at BL, higher than median EGF concentrations associated with poor outcome independently of treatment arm, whereas low IL-2 had the opposite effect (p = 0.003 for both). Only OPN showed a significant treatment by factor interaction at BL (p < 0.01), suggesting that OPN has a differential effect on PFS in the two arms. Pts with high OPN benefitted more from single agent SR (7.74 vs. 3.93 mos for the combination; p = 0.007), but no differences were found for those with low OPN. Lower than median on-treatment increases in sCA9 (D28, p = 0.01) and GRO-alpha (D56, p = 0.04) on SR only were also associated with a better outcome. A 6-marker CAF signature at BL containing OPN, sCA9, VEGF, sVEGFR-2, ColIV, and TRAIL demonstrated predictive value on PFS. Conclusions: A CAF signature showed potential value in predicting differential benefit from single agent SR vs. SR+IFN in mRCC. Broad-based screening of circulating CAFs may identify predictive and prognostic biomarkers in the context of clinical trials.

[Table: see text]

Outcome of patients (pts) with metastatic renal cell carcinoma (mRCC) treated with systemic therapy without cytoreductive nephrectomy (CN)

e16035

Background: Targeted therapies (TT) have replaced cytokines in the management of pts with mRCC. CN has been incorporated in the management of pts with mRCC but many pts are not suitable candidates for CN. The median overall survival (OS) time of pts treated with interferon alfa (IFN-α) without CN was 7.8 months (mos) [Flanigan et al. Journal of Urology 2004]. The median OS time for pts with mRCC treated with TT sequentially without CN is unknown. Methods: We retrospectively reviewed the medical records of pts with mRCC who did not undergo CN and who received one or more TT (bevacizumab, sorafenib, sunitinib, or temsirolimus) sequentially for at least one month with or without chemotherapy (gemcitabine + capecitabine or 5-FU). We calculated OS time from date of diagnosis until date of death or last follow up. We excluded pts who had embolization, radiofrequency ablation or cryotherapy of the primary tumor. Results: We identified 88 pts between Jan 2002 and Dec 2007. Median follow-up time is 9.7 mos (range: 1.2–49.2). Median OS time for all pts is 10.7 mos (95% CI: 7.6–15.4). 55 pts (62.5%) had clear-cell and 33 (37.5%) had non-clear cell histology, with median OS times of 15.1 mos (95% CI: 9.6–17.7) and 7.4 mos (95% CI: 4.4–13.0), respectively. ECOG performance status (PS) at time of diagnosis was correlated with OS (HR 1.54; 95% CI: 1.16–2.05; p<0.01). Pts with PS 0, 1, 2, and 3 had median OS times of 22.8 mos (95% CI: 5.7,*), 16.5 mos (95% CI: 8.1–24.7), 7.6 mos (95% CI: 5.7–11.9), and 7.1 mos (95% CI: 3.3–9.6), respectively. Pts with clinical evidence of lymph node (LN) involvement had worse outcome,with median OS time of 7.6 mos (95% CI: 5.6–9.8) versus 17.2 mos (95% CI: 9.8–35.5) for pts without clinical evidence of LN involvement. Conclusions: In this analysis, median OS time for pts with mRCC treated in the modern era with TT without CN is superior to historical experience with IFN- α.Compromised PS, LN involvement, and non-clear cell histology were associated with worse outcome. This data is useful in the design of randomized trials investigating the role of CN in mRCC.

[Table: see text]

Treatment of poor-risk metastatic renal carcinoma patients with combination gemcitabine, capecitabine, and bevacizumab at a tertiary cancer center

e16112

Background: Treatment of poor risk metastatic renal carcinoma (mRCC) is challenging, and empiric combinations may be attempted in practice once conventional therapies fail. These combinations may lead to formal clinical trials. Evaluation of mRCC patients given an empiric combination of gemcitabine (gem) capecitabine (cap), and bevacizumab (bev) at a tertiary care center was performed. Methods: After obtaining IRB approval, non investigational use of gem in combination with cap and bev in mRCC patients was identified using institutional databases. Collected data included demographics, previous therapies, number of metastatic sites, MSKCC risk stratification variables, prior nephrectomy status, drug therapy duration, and progression-free survival (PFS). Descriptive statistics were employed for data analysis. Results: Thirty-six patients were included in the analysis, with a median age of 55.5 years. Seventeen patients (47%) had previously received a tyrosine kinase inhibitor (TKI). Twenty-two patients (61%) had clear cell histology, 13 patients (36%) had sarcomatoid features, 20 patients (56%) had undergone previous nephrectomy, 20 patients (56%) had four or more sites of metastasis and 27 patients (75%) were diagnosed within 1 year of therapy. Initial treatment consisted of gem (908.61 mg/m2) every 2 weeks, cap (2.75 grams/day), and bev (828.82 mg) every 2 weeks. The median PFS for the study population was 5.83 months. The subset of TKI patients had a median PFS of 5.4 months. Therapy was relatively well tolerated with only 3 patients discontinuing one or more of the drugs due to adverse reactions. Thirteen of the patients started a TKI post discontinuation of the triple therapy. Conclusions: The triple therapy combination in this retrospective evaluation provides promising efficacy and acceptable tolerability in patients with poor prognosis mRCC. Based on these observations, a phase II is now underway assessing gemcitabine, capecitabine and becacizumab in patients with sarcomatoid RCC.

[Table: see text]

Hypoxia-inducible factor-1α (HIF-1α) modulation in combination with anti-angiogenic therapy

3555

Background: HIF-1α mediates adaptive responses to hypoxic conditions induced by anti-angiogenic therapy. Bortezomib has demonstrated the ability to inhibit transcriptional activity of HIF-1α. We hypothesized that the addition of bortezomib to bevacizumab would augment response, and we performed this phase I trial to assess safety, MTD, and correlative studies of anti-angiogenic activity. Methods: Patients with advanced malignancy refractory to standard therapy were eligible. Cohorts of 6 patients received bevacizumab and bortezomib on a 3-week cycle, with a stair-step dose escalation design. Pharmacodynamic assessment included plasma VEGF, VEGFR2, 20S proteasome inhibition, DCE-MRI, and tumor expression of HIF-1α, VEGF, VEGFR2, and polymorphisms of VEGF and VEGFR2. Results: 71 patients were treated, and the MTD was identified at the highest dose level (bevacizumab 15 mg/kg, bortezomib 1.3 mg/m2). Two partial responses were observed in patients with renal cell carcinoma (RCC) (Total patients with RCC = 6). Minor responses or stable disease lasting ≥4 months was achieved in 8 patients, including RCC (1), breast (1), leiomyosarcoma (1), nasopharyngeal (2), hepatocellular (1), neuroendocrine (1), lacrimal gland adenocystic carcinoma (1). The most common drug-related toxicities observed included hypertension (36%), fatigue (34%), thrombocytopenia (29%), and myalgia (19%). 22 patients (31%) experienced no drug-related toxicities greater than grade 1. 56 patients (79%) experienced no drug-related toxicities greater than grade 2. One DLT (G5 bleeding) was observed at the MTD. Plasma VEGF levels demonstrated decreases at 1 and 4 hours post-infusion, followed by increases to levels above baseline on days 2, 3, and at the end of cycle 1. DCE-MRI analysis demonstrated decreases in Ktrans on days 2 and 3. Analysis of HIF-1α expression in biopsies is underway. Conclusions: Combination bevacizumab and bortezomib is well-tolerated and has demonstrated clinical activity in patients with previously treated, advanced malignancy. Pharmacodynamic assessment with biomarkers and DCE-MRI suggests that inhibition of angiogenic activity was achieved. Updated clinical and biomarker data will be presented.

No significant financial relationships to disclose.

Cytokines and angiogenic factors in metastatic renal cell cancer: Association of pretreatment serum levels with survival

e16036

Background: To correlate serum cytokine and angiogenic factor (CAF) levels and overall survival (OS) in metastatic renal cell cancer (mRCC) treated with interferon-alpha (IFN-α). Methods: Serum CAF levels were measured in 103 patients treated on a randomized trial with IFN-α 0.5 million units (MU) twice daily or 5 MU daily. Concentrations of 17 analytes including vascular endothelial growth factor (VEGFA) and several cytokines were determined by multiplex bead immunoassays or ELISA (basic fibroblast growth factor). We used proportional hazards models to evaluate the effect of CAF levels and clinical factors on OS. Results: Pretreatment serum interleukin (IL)-5, IL-12p40, VEGFA, and IL-6 levels, and Memorial Sloan-Kettering Cancer Center risk grouping were independently correlated with OS, with hazard ratios of 2.33, 2.00, 2.07, 1.82 and 0.39, respectively (concordance index = 0.69 for the combined model versus 0.60 for the CAF model versus 0.52 for the clinical model). Based on an index derived from these five risk factors (RF), patients with 0–2 RF had a median OS time of 32 months, versus 9 months for patients with 3–5 RF (p < 0.0001). Conclusions: Serum CAF profiling contributes to prognostic evaluation in mRCC and helps to identify a subset of patients with 20% 5-year OS.

No significant financial relationships to disclose.

A phase II randomized four-regimen selection trial incorporating response for sequential chemotherapy in metastatic, unresectable urothelial cancer: Final results from the M. D. Anderson Cancer Center

5071

Background: We developed a clinical trial incorporating response into the treatment algorithm. Patients meeting a certain threshold of response continued with the same treatment; those with insufficient response were switched to alternative chemotherapy. We now report on final results from this trial. Methods: Patients were randomly assigned to one of four regimens: ifosfamide, doxorubicin, gemcitabine; ifosfamide, paclitaxel, cisplatin; gemcitabine, cisplatin; or cisplatin, gemcitabine, and ifosfamide. To continue with chemotherapy, patients must have had at least a 40% response after the first 6-week interval, and a >90% response after the second 6 weeks. Otherwise, they were re-randomized to alternate chemotherapy. Overall success (OSX) was defined as patients with a >90% response with either front-line or second-line therapy. Surgical consolidation was offered to patients at the discretion of their treating physician. Results: Median overall survival (OS) for 120 patients was 19.1 mo. (3 and 5-yr survival: 33% and 20%). OSX was achieved in 41 patients (median OS: 51 mo.); the median OS in the other 79 patients was 15 mo. (p = 0.0001), with a 5-yr survival of 42% and 10% respectively. Surgical consolidation was performed in 35 patients: 23 with nodal metastases to pelvic and/or RPLN, 6 with cT4b tumors, and an additional 6 patients with distant metastases. Their median OS from surgery was 23.7 months, (5-yr survival: 31%). Surgical consolidation in the setting of OSX was associated with a 42% 5-yr survival as compared to 11% in those undergoing surgery in the absence of OSX. Visceral metastases and poor performance status were associated with a worse prognosis. Conclusions: With sequential therapy, 34% of patients had a >90% response (OSX). A potential benefit in long-term survival was seen in patients who had surgical consolidation in the setting of OSX. This trial design provides a novel method for assessing the benefits of sequential chemotherapy, and enhancing the population of patients who may be offered surgical consolidation in the setting of initially unresectable, or metastatic urothelial cancer.

No significant financial relationships to disclose.

Organic arsenic in patients (pts) with advanced solid tumors: Phase-1 results of zio-101 (s-dimethylarsino-glutathione)

3554

Background: ZIO-101(S-dimethylarsino-glutathione), a novel organic arsenic, is active against multiple cancers in vitro and in animal models. Anti-cancer activity is multifaceted and is mediated by disrupted mitochondrial function, increased reactive oxygen species (ROS) production, modified signal transduction and anti-angiogenesis. Methods: Phase-1 dose finding study to determine maximum tolerated dose (MTD), dose-limiting toxicity (DLT), pharmacokinetics (PK), and toxicities of ZIO-101 in patients with advanced solid tumors. Results: 34 pts (18 M/16 F) received 78–588 mg/m2/d IV for 5 consecutive days every 4 weeks. Median age was 61 (range, 42–79 y). Median N prior regimens was 3 (1–5). Pts had colorectal (N=17; 12 evaluable), renal (N=4), lung (N=3), melanoma (N=2), pancreas (N=2) and others (N=6). Median N of cycles was 2 (range, 1–12). MTD is 420 mg/m2/d and DLT was transient confusion, and ataxia. Fatigue, nausea and emesis were = grade-2. ZIO-101 was otherwise well-tolerated: There are no hematological toxicities and no QTc- prolongation. Five patients had stable-disease 4–12 mo (colorectal [N=3], renal [N=2],). PK studies at 420 mg/m2/d: tmax = 1 h (SD + 0.9), Cmax = 1.06 μg/L (SD ± 0.07 μg/mL), t1/2 = 17.8 h (SD ± 1.4 h) and AUC0- 8 = 25.9 mg·h/L (SD ± 0.8mg.h/L). 1 pt had complete resolution of a brain metastasis (renal) and 1 patient had a substantial decrease of a liver metastasis (pancreas). Conclusions: ZIO-101 was well tolerated. MTD is 420 mg/m2/d and DLT is transient confusion and ataxia. There was observed clinical benefit in five patients. Expansion cohort is ongoing to further test toxicities and antitumor activity. Phase II studies are ongoing.

[Table: see text]

Von Hippel-Lindau gene mutation status is associated with a dichotomous response in primary and metastatic tumors in patients receiving bevacizumab and erlotinib for metastatic renal cell carcinoma

15522

Background: A single arm phase II study is underway evaluating the safety and clinical benefit of presurgical bevacizumab and erlotinib in the management of patients with untreated conventional renal cell carcinoma (RCC). It is not known how the presence or absence of von Hippel Lindau (VHL) mutations affect the response to therapy in the primary or metastatic site, and whether VHL mutational status is predictive for either. Methods: Patients enrolled had conventional RCC, measurable metastatic disease, a primary tumor in place, no prior systemic therapy, a PS of 0 or 1 and no brain metastases. A total of 35 patients were enrolled as of January 8, 2007. Patients were treated with bevacizumab for 4 cycles and erlotinib for 8 weeks, and underwent cytoreductive nephrectomy at week 10 (4 weeks after the last dose of bevacizumab). A VHL gene mutation and methylation analysis was completed on nephrectomy specimens from the first 18 evaluable patients. Patients were grouped according to the presence or absence of functional VHL gene inactivation (mutation and/or methylation). Two-sample T-test and Fisher’s exact test were performed. Results: Ten patients (55%) demonstrated either VHL mutation or methylation ( table 1 ). Patients with no VHL gene inactivation demonstrated more robust primary tumor shrinkage, but did not demonstrate partial responses (PRs). Table 1 . Conclusions: These findings, although preliminary, suggest a dichotomous response in the primary and metastatic disease sites according to VHL functional status. Ongoing evaluation of new treatment strategies using antivascular/targeted agents in RCC may benefit from molecular stratification.

[Table: see text]

No significant financial relationships to disclose.

Randomized phase II study of sorafenib with or without low-dose IFN in patients with metastatic renal cell carcinoma

5104

Background: An 80 patient randomized open label phase II study is underway evaluating the safety and clinical benefit of sorafenib with or without low-dose interferon (LD IFN) in patients with untreated metastatic conventional (clear cell) renal cell carcinoma (mRCC). Prior studies combining sorafenib and conventional dose IFN demonstrated a response rate (RR) in the 20–30 percent range, higher than the 2–10 percent RR seen with sorafenib monotherapy, but with increased toxicity. Prior data suggest equivalent efficacy between LD and conventional dose IFN with fewer side effects. We postulated that low-dose IFN will add to the clinical benefit of sorafenib in patients with mRCC with minimal additional toxicity. Methods: Eligibility included conventional mRCC, measurable disease, no prior systemic therapy, a PS of 0 or 1 and no brain metastases. Patients were treated with sorafenib 400mg PO BID or sorafenib at the same dose plus interferon alfa 0.5 million units SC BID. Primary endpoints included response rate and progression free survival (PFS). The probabilities of PFS and overall survival (OS) were estimated for each arm using Kaplan-Meier methods. Median PFS and OS were summarized, along with the 95% confidence intervals for each arm separately. Results: A total of 60 patients were enrolled as of January 8, 2007. Five patients were inevaluable, and 5 patients had not undergone first restaging. Treatment was well tolerated in both groups. Best response and PFS are summarized below. In the sorafenib arm, 13 out of 25 patients progressed or died. The median time to progression was 9.3 months (95% CI 5.8- not reached). In the sorafenib + IFN arm, 13 out of 25 patients progressed or died. Median time to progression was 9.3 months (95% CI 5.2- not reached). Median OS was not reached in either arm. Conclusions: These findings, although preliminary, suggest that adding low dose interferon therapy to sorafenib therapy does not provide superior cytoreduction of metastatic RCC, but provides equivalent PFS.

[Table: see text]

No significant financial relationships to disclose.