Contrast enhanced CT (CE-CT) changes and nephrometry down-scoring of unresectable primary renal cell carcinoma (RCC) tumors in patients (Pts) treated with neoadjuvant sunitinib

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Background: The impact of neoadjuvant sunitinib on CE-CT parameters and nephrometry score of primary RCC tumors remains unknown.

Methods: Retrospective review of baseline and prenephrectomy CE-CT from a prospective phase II trial of neoadjuvant sunitinib (50 mg sunitinib continuous dosing) in unresectable primary RCC tumors with or without metastatic disease. CE-CT parameters and R.E.N.A.L. nephrometry score for each lesion were determined in pts who underwent subsequent surgery. RECIST and MASS criteria were used to assess primary tumor radiographic response. CT changes were analyzed using the sign test and Wilcoxon signed rank test.

Results: Twenty nine pts were enrolled, of which 13 pts (85%M; median age 63y) underwent post-sunitinib resection of 16 primary tumors (3 pts had multifocal RCC). Post-therapy, 88% of tumors had decreased long diameter (median 32% decrease, p<0.001 vs. baseline), 88% decreased attenuation (median 30 HU reduction, p=0.006) and 69% increased necrosis (p=0.001). 56% of tumors had a decrease in nephrometry score (median 1 point decrease; 10 to 9, p=004). At baseline, 81% of tumors were highly complex by nephrometry score; following therapy 46% of the highly complex tumors became moderately complex. At baseline 13 tumors abutted renal hilar vital structures, whereas following treatment 4 tumors demonstrated abutment. Adenopathy decreased (range, 23%-83%) in 4/4 patients with enlarged baseline lymph nodes, with complete resolution in 1 patient. RECIST objective response was seen in 38% and SD in 56% of primary tumors; 1 tumor had PD based on size despite > 95% necrosis. MASS criteria response was favorable 38%, intermediate 62%. Two of four pts had reduction in extent of venous thrombus (1 pt from level 0 to resolved and 1 pt from level IV to II).

Conclusions: Neoadjuvant sunitinib resulted in decreased size/attenuation, increased necrosis of the primary tumor and reduction in lymphadenopathy and venous thrombus in pts who underwent subsequent surgery. Sunitinib reduced the RENAL nephrometry score and facilitated nephrectomy, notably due to impact on tumor proximity to vital structures in the renal hilum.

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Cessation of VEGF-targeted therapy in patients with metastatic renal cell carcinoma (mRCC): Feasibility and clinical outcome

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Background: Standard practice in the treatment (tx) of mRCC with VEGF targeted agents is continuous tx until progression of disease (PD) or unacceptable toxicity. Chronic mild to moderate toxicity and risk of long-term toxicity ensue for a subset of pts. It is hypothesized that a subset of pts with an initial response to tx can maintain disease control off all tx for a period of time.

Methods: A retrospective study of mRCC pts who initiated VEGF-targeted tx between January 2004 and November 2009 was conducted. Pts had achieved disease control on tx, then were taken off all tx. Pt, disease and tx characteristics were recorded. Progression free survival (PFS) was measured as the time from discontinuation of tx to RECIST PD.

Results: A total of 30 pts were identified. All pts had prior nephrectomy and had clear cell histology, and 9 patients had prior immunotherapy. At the time tx was stopped 16 pts were receiving sunitinib, 7 pts were receiving sorafenib (2 in combination with AMG 386), and 7 pts were receiving bevacizumab (6 in combination with temsirolimus, 1 with IFN-alpha). Six pts had achieved CR, 19 PR and 5 SD by RECIST. Using Heng's prognostic risk group criteria, 14 pts had favorable, 14 had intermediate, and 2 had poor risk disease prior to initiation of VEGF-targeted tx. Therapy was held for severe adverse events (5pts; 2 MIs, 3 CVAs), toxicity (16 pts; 4 diarrhea, 3 skin, 3 proteinuria, 2 cardiac, 1 fatigue, 1 stomatitis, 1 pneumonitis, 1 nausea), cost (1 pt; high co-pay), pt choice (6 pts) and interventions (2 pts; 1 angioplasty and 1 kidney stone). Median follow up is 29 months (range 11– 82). Median duration of tx prior to discontinuation was 14.6 months (range 3–79). Thirteen pts (43%) had PD off tx (lymph nodes (6), lungs (8; 3 with new lesions), bones (1), brain (2; 1 with new lesions)) with a median PFS of 10 months (range 3–27). After PD, 4 pts were offered sunitinib, 1 pazopanib, 1 everolimus, 1 local RF tx, and 6 continued expectant management. After a median follow-up to date of 7.5 months (2–28), 17 pts (57%) still did not have RECIST PD.

Conclusions: Select mRCC pts with disease control on VEGF-targeted tx can be safely observed off all tx. Further prospective investigation is needed to define the risks and benefits of this approach.

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Association of tumor burden characteristics with outcomes in patients (pts) with metastatic renal cell carcinoma (mRCC) treated with sunitinib

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Background: An important goal of non-curative therapy for mRCC is tumor burden (TB) control. However, the impact of tumor burden characteristics on clinical outcome has not been studied in mRCC pts treated with VEGF-targeted therapy. Methods: Pts with clear-cell mRCC treated with sunitinib from June 1, 2004, to October 5, 2007, were retrospectively identified. CT scan images were re-reviewed from baseline, at the time of maximal tumor burden shrinkage (TS), at time of disease progression and at time of last assessment prior to death. TB and percent TS were measured per RECIST criteria. Results: Sixty-nine pts were identified. The majority (54%) were favorable risk based on CCF TKI risk group classification. All pts underwent prior nephrectomy and 77% had received prior systemic therapy. Sites of metastases included: lung (87%), mediastinal lymph nodes (52%), retroperitoneal lymph nodes (36%), adrenal (29%), bone (38%), liver (22%), pancreas (14%), kidney (7%), and brain (6%). There were a median of 8 metastatic deposits across all organs (range, 1–20). Median TB at start of therapy was 14.0 cm (range, 3.0–42.2 cm). Overall response rate was 52% and 87% had some degree of TS. Median progression-free survival (PFS) and overall survival (OS) were 13.5 months and 30.9 months, respectively. In multivariable analysis, disease confined to above the diaphragm (p = 0.03) and total TB <13cm (p = 0.09) prior to sunitinib were independent positive predictors of PFS. Total number of metastases <10 (p < 0.001) and tumor volume above the diaphragm <6.5 cm (p = 0.05) were independent positive predictors of OS. Increased TS while on sunitinib was also prognostic for OS (p < 0.001). Fifty-nine pts (86%) have progressed. At time of disease progression (PD), tumor location and pattern of progression were not associated with OS. However, total TB (p = 0.003) and total number of metastatic deposits (≤12 vs. >12, p < 0.001) were significant predictors of OS from PD. At the time of last assessment prior to death, median TB was 23.9 cm, significantly higher (p < 0.001) than in pts still alive (median TB 14.4 cm). Conclusions: Tumor burden shrinkage and tumor burden at time of disease progression are associated with overall survival in pts with mRCC treated with sunitinib.

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Association of percentage of tumor burden removed with debulking nephrectomy and progression-free survival (PFS) in metastatic renal cell carcinoma (mRCC) patients (Pts) treated with VEGF-targeted therapy

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Background: Debulking nephrectomy is a standard of care in mRCC, although data in patients subsequently treated with targeted therapy is lacking. The objective of this study was to determine if fractional percentage of tumor volume (FPTV) removed with debulking nephrectomy is associated with PFS on subsequent VEGF-targeted therapy. Methods: The Cleveland Clinic Urologic Oncology database from 2005–2008 was retrospectively reviewed to identify mRCC patients who had undergone debulking nephrectomy followed by VEGF-targeted therapy, defined as treatment with sunitinib, sorafenib, bevacizumab or sunitinib + bevacizumab. FPTV was determined by the diameter of the primary tumor divided by the total tumor burden (per RECIST criteria) by investigator re-review of imaging studies. PFS was defined from the start date of systemic therapy to disease progression per RECIST criteria. Results: Seventy-five Pts were identified; 76% male, median age 60 years (range, 34–84), 95% clear cell histology and 69% ECOG PS 0. Pts received treatment with bevacizumab (28 pts), sunitinib (23), sorafenib (20), or sunitinib + bevacizumab (4). Lung (76%) and lymph node (48%) were the predominant sites of metastasis. The median diameter of the primary tumor was 9.3 cm (range, 3.3–21 cm). The median FPTV removed was 95% (range, 80–99%). The median PFS was 12 months. In univariable analysis, the FPTV removed was associated with prolonged PFS (p < 0.001), as were low nuclear grade (p = 0.009), longer interval from diagnosis to treatment (p = 0.05), normal hemoglobin (p = 0.02), number of metastatic sites (p = 0.05), and lack of lung (p = 0.05) and brain (p = 0.05) metastasis. In multivariable analysis, the FPTV removed, as well as the interval from diagnosis to treatment (p = 0.03), were found to be independent predictors of PFS (< 0.001). Conclusions: Improved PFS on targeted systemic therapy is significantly associated with a greater percentage of tumor burden removed at debulking nephrectomy.

No significant financial relationships to disclose.

An association study of 43 SNPs in 16 candidate genes with atorvastatin response

Variation in individual response to statin therapy has been widely studied for a potential genetic component. Multiple genes have been identified as potential modulators of statin response, but few study findings have replicated. To further examine these associations, 2735 individuals on statin therapy, half on atorvastatin and the other half divided among fluvastatin, lovastatin, pravastatin and simvastatin were genotyped for 43 SNPs in 16 genes that have been implicated in statin response. Associations with low-density lipoprotein cholesterol (LDL-C) lowering, total cholesterol lowering, HDL-C elevation and triglyceride lowering were examined. The only significant associations with LDL-C lowering were found with apoE2 in which carriers of the rare allele who took atorvastatin lowered their LDL-C by 3.5% more than those homozygous for the common allele and with rs2032582 (S893A in ABCB1) in which the two groups of homozygotes differed by 3% in LDL-C lowering. These genetic effects were smaller than those observed with the demographic variables of age and gender. The magnitude of all the differences found is sufficiently small that genetic data from these genes should not influence clinical decisions on statin administration.

Oprelvekin: an alternative treatment for thrombocytopenia

Oprelvekin (Neumega, Genetic Institute Co., Cambridge, MA) is a thrombopoietic growth factor approved by the U.S. Food and Drug Administration for the prevention of severe thrombocytopenia following myelosuppressive chemotherapy in patients with nonmyeloid malignancies. The most common side effects are edema, dyspnea, tachycardia, and conjunctival redness. Patient-care concerns include appropriate timing of administration, patient selection, dosing and administration issues, and the early identification and management of side effects.

Mutations and deletions within the S8-S9 interdomain region abolish complementation of N- and C-terminal domains of Ca(2+)-activated K+ (BK) channels

A full length alpha-subunit of the Ca(2+)-activated K+ (BK) channel with an inactivating mutation in the C-terminus can complement a functional C-terminal fragment. We analyzed deletions and amino acid changes within the S8-S9 interdomain region for their ability to allow complementation. Cys612 and His616 that are located in a region that contains two overlapping signature sequences, a immunoglobulin signature sequence and a heme binding domain, are essential for a functional channel. These two amino acid residues are also essential for complementation. The deletion of the PEST sequence does not affect the function of the BK channel; however, without the PEST sequence, complementation by a functional C-terminal fragments is no longer possible. The ability to complement a functional channel is restricted to the C-terminal fragment and requires that the complete alpha-subunit or the larger N-terminal fragment contains both, the immunoglobulin signature sequence the PEST sequence.

Molecular cloning of the bovine alpha 1(IV) procollagen gene (COL4A1) and its use in investigating the regulation of expression of type IV procollagen by retinoic acid in bovine lens epithelial cells

This report is the first to describe the isolation of a 400 base pair cDNA clone encoding part of the bovine alpha 1(IV) procollagen. Using the polymerase chain reaction (PCR), we have amplified a sequence of approximately 400 bp from this gene within the recombinant phage DNA. The cloned sequence encodes 94 amino acids that form part of the protein's helical region. The sequence contains one interruption in the Gly-Xaa-Yaa repeat unit. The third base of the codon for glycine at several sites differs from those seen in murine and human genes, as does the third base of proline codons. The bovine cDNA also contains fewer thymine residues. Northern blot hybridization has shown that the mRNA for bovine procollagen to be 6.2 kb in size. We have used the cDNA clone to investigate the effect of all-trans retinoic acid (RA) on the gene expression of alpha 1(IV) procollagen in cultured bovine lens epithelial (LE) cells. We have also observed that RA decreases total protein production and concomitantly increases type IV procollagen in a concentration dependent manner. An increase in alpha 1(IV)mRNA as well as increase in type IV procollagen suggest that the regulation of alpha 1(IV) gene by RA in the LE cells is at the transcriptional level. Further, our results support the hypothesis that RA inhibition of lens epithelium transformation to fibroblast-like cells may be due to the ability of RA to stimulate the production of basement membrane components by epithelia.

Cloning and functional expression of a human gene, hIRK1, encoding the heart inward rectifier K+-channel

We have isolated a cDNA clone encoding a human inward rectifier potassium channel (hIRK1). The nucleotide (nt) sequence of the coding region is 88% similar to the mouse clone with only seven amino-acid (aa) differences. The hIRK1 cRNA initially expressed low levels of protein in a wheat germ system and in Xenopus oocytes. The addition of a SmaI site 3' to the poly(A) tail increased the expression at least tenfold. Xenopus oocytes injected with the hIRK1 cRNA developed resting potentials that averaged -96 mV and a large inward current that was blocked by Ba2+ or Cs+. The hIRK1 EK shifted 54.6 mV per decade change in [K]o, and its channel conductance increased with [K]o by a 0.3 exponent factor. Above EK, the hIRK1 I-V relation has a distinct 'N'-shape. Cell-attached single-channel conductance in 140 mM K+ pipette solution averaged 29 pS. The negative resting potential and the 'N'-shape I-V relation of hIRK1 closely resemble that of the native cardiac inward rectifier IK1.