Dimitris Voliotis

Sorafenib in Advanced Hepatocellular Carcinoma

BACKGROUND No effective systemic therapy exists for patients with advanced hepatocellular carcinoma. A preliminary study suggested that sorafenib, an oral multikinase inhibitor of the vascular endothelial growth factor receptor, the platelet-derived growth factor receptor, and Raf may be effective in hepatocellular carcinoma. METHODS In this multicenter, phase 3, double-blind, placebo-controlled trial, we randomly assigned 602 patients with advanced hepatocellular carcinoma who had not received previous systemic treatment to receive either sorafenib (at a dose of 400 mg twice daily) or placebo. Primary outcomes were overall survival and the time to symptomatic progression. Secondary outcomes included the time to radiologic progression and safety. RESULTS At the second planned interim analysis, 321 deaths had occurred, and the study was stopped. Median overall survival was 10.7 months in the sorafenib group and 7.9 months in the placebo group (hazard ratio in the sorafenib group, 0.69; 95% confidence interval, 0.55 to 0.87; P<0.001). There was no significant difference between the two groups in the median time to symptomatic progression (4.1 months vs. 4.9 months, respectively, P=0.77). The median time to radiologic progression was 5.5 months in the sorafenib group and 2.8 months in the placebo group (P<0.001). Seven patients in the sorafenib group (2%) and two patients in the placebo group (1%) had a partial response; no patients had a complete response. Diarrhea, weight loss, hand-foot skin reaction, and hypophosphatemia were more frequent in the sorafenib group. CONCLUSIONS In patients with advanced hepatocellular carcinoma, median survival and the time to radiologic progression were nearly 3 months longer for patients treated with sorafenib than for those given placebo. (ClinicalTrials.gov number, NCT00105443.)

Phase I Clinical and Pharmacokinetic Study of the Novel Raf Kinase and Vascular Endothelial Growth Factor Receptor Inhibitor BAY 43-9006 in Patients With Advanced Refractory Solid Tumors

PURPOSE BAY 43-9006 is a novel dual-action Raf kinase and vascular endothelial growth factor receptor inhibitor that inhibits tumor cell proliferation and angiogenesis. This study established the safety and pharmacokinetics of BAY 43-9006 in 69 patients with advanced refractory solid tumors. PATIENTS AND METHODS BAY 43-9006 (50 to 800 mg) was administered once or twice daily on a varying weekly schedule. Pharmacokinetic sampling was performed in all patients; preliminary tumor response was also assessed. The effect of BAY 43-9006 on phorbol myristate acetate-stimulated ERK phosphorylation in peripheral blood lymphocytes was studied using flow cytometry. RESULTS Mild to moderate diarrhea was the most common (55%) treatment-related adverse event. The maximum-tolerated dose was 400 mg bid continuous. Dose-limiting toxicities were grade 3 diarrhea and fatigue at 800 mg bid, and grade 3 skin toxicity at 600 mg bid. BAY 43-9006 pharmacokinetics were highly variable for single and multiple dosing, and toxicity did not appear to be dose dependent. Significant decreases of phorbol myristate acetate-stimulated ERK phosphorylation (P < .01) were identified at doses >/= 200 mg bid continuous. Forty-five patients were assessable for efficacy; one patient had a partial response (hepatocellular carcinoma at 400 mg bid continuous), 25 patients had stable disease, with eight lasting > 6 months and five for >12 months. Eighteen patients had progressive disease, and tumor response could not be evaluated in one patient. CONCLUSION Oral BAY 43-9006 was well tolerated and appeared to provide some clinical benefits. Based on the results of this study, BAY 43-9006 at 400 mg bid continuous is recommended for ongoing and future studies.

Efficacy and safety of sorafenib in patients with advanced hepatocellular carcinoma: subanalyses of a phase III trial.

BACKGROUND & AIMS The Sorafenib Hepatocellular Carcinoma (HCC) Assessment Randomized Protocol (SHARP) trial demonstrated that sorafenib improves overall survival and is safe for patients with advanced HCC. In this trial, 602 patients with well-preserved liver function (>95% Child-Pugh A) were randomized to receive either sorafenib 400mg or matching placebo orally b.i.d. on a continuous basis. Because HCC is a heterogeneous disease, baseline patient characteristics may affect individual responses to treatment. In a comprehensive series of exploratory subgroup analyses, data from the SHARP trial were analyzed to discern if baseline patient characteristics influenced the efficacy and safety of sorafenib. METHODS Five subgroup domains were assessed: disease etiology, tumor burden, performance status, tumor stage, and prior therapy. Overall survival (OS), time to progression (TTP), disease control rate (DCR), and safety were assessed for subgroups within each domain. RESULTS Subgroup analyses showed that sorafenib consistently improved median OS compared with placebo, as reflected by hazard ratios (HRs) of 0.50-0.85, similar to the complete cohort (HR=0.69). Sorafenib also consistently improved median TTP (HR, 0.40-0.64), except in HBV-positive patients (HR, 1.03), and DCR. Results are limited by small patient numbers in some subsets. The most common grade 3/4 adverse events included diarrhea, hand-foot skin reaction, and fatigue; the incidence of which did not differ appreciably among subgroups. CONCLUSIONS These exploratory subgroup analyses showed that sorafenib consistently improved median OS and DCR compared with placebo in patients with advanced HCC, irrespective of disease etiology, baseline tumor burden, performance status, tumor stage, and prior therapy.

Relationship between baseline hepatic status and outcome, and effect of sorafenib on liver function: SHARP trial subanalyses

BACKGROUND & AIMS Hepatic markers are utilized in many classification systems of patients with hepatocellular carcinoma and, by measuring organ damage and tumor stage, can influence treatment. Moreover, elevated serum concentrations of aminotransferases and alpha-fetoprotein are indicators of poor prognosis in patients with hepatocellular carcinoma. We examined the effects of sorafenib on hepatic markers by performing exploratory subset analyses of the Sorafenib HCC Assessment Randomized Protocol (SHARP) trial in patients categorized by baseline concentrations of alanine aminotransferase/aspartate aminotransferase, alpha-fetoprotein, and bilirubin; and by evaluating the effects of sorafenib on bilirubin concentrations during treatment. METHODS Patients (n=602) were grouped by baseline concentrations of alanine aminotransferase/aspartate aminotransferase (not significantly elevated, mildly elevated, or moderately elevated), alpha-fetoprotein (normal or elevated), and bilirubin (normal or elevated). Bilirubin was measured at baseline and on day 1 of each cycle. RESULTS Patients with elevated baseline concentrations of alanine aminotransferase/aspartate aminotransferase, alpha-fetoprotein, or bilirubin had shorter overall survival (OS) than those with normal baseline concentrations, irrespective of treatment group. No notable differences in safety profiles were observed between patients with normal vs. elevated alanine aminotransferase/aspartate aminotransferase, alpha-fetoprotein, or bilirubin. Median changes from baseline in bilirubin concentration at the last cycle of treatment were +0.17 and +0.19 mg/dl in the sorafenib and placebo groups, respectively. CONCLUSIONS These subset analyses suggest that sorafenib is safe and effective for hepatocellular carcinoma, irrespective of baseline alanine aminotransferase/aspartate aminotransferase, alpha-fetoprotein, or bilirubin concentration and that hepatic function remains stable over the course of sorafenib therapy.

The Raf kinase inhibitor BAY 43-9006 reduces cellular uptake of platinum compounds and cytotoxicity in human colorectal carcinoma cell lines.

Raf kinase plays a central role in oncogenic signaling and acts as a downstream effector of Ras in the extracellular signal-regulated (ERK) kinase pathway. BAY 43-9006 (BAY) is a novel signal transduction inhibitor that prevents tumor cell proliferation and angiogenesis through blockade of the Raf/MEK/ERK pathway at the level of Raf kinase and the receptor tyrosine kinases vascular endothelial growth factor receptor-2 and platelet-derived growth factor receptor-&bgr;. The present study evaluates the effects of combining BAY and platinum derivatives on human colorectal cancer cells using different incubation protocols. Our data show that the combination of oxaliplatin or cisplatin with BAY results in marked antagonism irrespective of the used application schedule. Furthermore, BAY abrogates the cisplatin-induced G2 arrest as well as the G1 arrest induced by oxaliplatin. BAY alone arrests cancer cells in their current cell cycle phase and affects cell cycle regulative genes. Specifically, BAY reduced the protein expression of p21Cip1 as well as cyclin D1, and inhibits the expression of cdc2 (cdk1). Utilizing atom absorption spectrometry, BAY significantly reduced cellular uptake of platinum compounds and thereby the generation of DNA adducts. Taken together, co-incubation with BAY results in reduced cellular uptake of platinum compounds and consecutively reduced generation of DNA adducts, and eventually decreased cellular cytotoxicity in human colorectal cancer cells. Our results indicate that the Raf kinase inhibitor BAY 43-9006 might also directly or indirectly interact with platinum transporter proteins in vitro.

Clinical Development of Sorafenib (BAY 43–9006) VEGFR and RAF Inhibitor

Sorafenib is a multi-kinase inhibitor with effects on the tumor cell and tumor vasculature that inhibit proliferation, promote cell death, and disrupt neo-angiogenesis. Originally identified as a Raf kinase inhibitor, sorafenib also inhibits VEGFR-1/-2/-3; PDGF-β receptor (PDGFR-β); Fms-like tyrosine kinase-3 (FLT-3); c-Kit protein (c-Kit); and RET receptor tyrosine kinases. Sorafenib has demonstrated potent anti-tumor activity in preclinical xenograft models of different tumor types by virtue of its anti-angiogenic, anti-proliferative and proapoptotic effects. This orally administered drug is well tolerated and received approval for the treatment of metastatic renal cell carcinoma (RCC) primarily based on a large international trial, the Treatment Approaches in Renal Cancer Global Evaluation Trial (TARGETs), in which 903 patients were randomized to receive sorafenib or placebo. At a planned interim analysis, patients treated with sorafenib had a lower risk for death than those treated with placebo. However, improvement in survival did not meet criteria for statistical significance. In a planned interim analysis of 769 patients, sorafenib significantly prolonged median progression-free survival compared with placebo (167 days vs 84 days; hazard ratio 0.44; P<0.000001). Sorafenib has also demonstrated early signs of clinical efficacy, alone or in combination regimens, in patients with advanced hepatocellular carcinoma (HCC) and melanoma. Ongoing phase III trials are currently being conducted to further evaluate sorafenib in HCC, melanoma, and non-small cell lung cancer. This chapter summarizes the discovery, preclinical findings, and clinical development of sorafenib in RCC and its potential use in other tumor types.