Tumour pharmacodynamics and circulating cell free DNA in patients with refractory colorectal carcinoma treated with regorafenib.

BACKGROUND: Regorafenib, a multi-kinase inhibitor, is used in the treatment of patients with metastatic colorectal cancer refractory to standard therapy. However, this benefit was limited to 1.4 months improvement in overall survival, with more than half of patients experiencing grade 3 to 4 adverse events. We aim to elucidate the pharmacodynamic effects of regorafenib in metastatic colorectal cancer and discover potential biomarkers that may predict clinical benefit. METHODS: Patients with metastatic colorectal adenocarcinoma refractory to standard therapy with tumours amenable to biopsy were eligible for the study. Regorafenib was administered orally at 160 mg daily for 3 out of 4 weeks with tumour assessment every 2 cycles. Metabolic response was assessed by FDG PET-CT scans (pre-treatment and day 15); paired tumour biopsies (pre-treatment and day 21 post-treatment) were sampled for immunohistochemistry and proteomic profiling analyses. Plasma circulating cell free DNA was quantified serially before and after treatment. RESULTS: There were 2(6%) partial responses out of 35 patients, and 8(23%) patients had stable disease for more than 7 months. Adverse event profile was similar to reported data. Recurrent somatic mutations in K-RAS, PIK3CA and BRAF were detected in plasma circulating cell free DNA in 14 patients; some mutations were not found in archival tumour. Total plasma circulating cell free DNA inversely correlated with progression free survival (PFS), and presence of KRAS mutations associated with shorter PFS. Immunohistochemistry of pre- and post- treatment biopsies showed majority of patients had downregulation of phosphorylated-VEGFR2, podoplanin, phosphorylated-AKT, Ki-67 and upregulation of the MEK-ERK axis, phosphorylated-C-MET, phosphorylated-SRC, phosphorylated-STAT3 and phosphorylated-JUN. Proteomic analysis of fine needle tumour aspirates showed down-regulation of PI3K was associated with longer PFS. CONCLUSION: Plasma circulating cell free DNA may yield potential predictive biomarkers of regorafenib treatment. Downregulation of the PI3K-AKT axis may be an important predictor of clinical benefit.

Phase II multicenter, uncontrolled trial of sorafenib in patients with metastatic breast cancer.

This trial was conducted to assess the efficacy and safety of sorafenib in patients with metastatic breast cancer. In this multinational, open-label phase II study, patients with metastatic breast cancer that had progressed after at least one prior chemotherapy regimen were continuously treated with oral sorafenib, 400 mg twice daily. The primary endpoint was overall best response; a secondary endpoint was percentage of patients with stable disease for greater than or equal to 16 weeks. Biomarker analysis were also performed. Of the 56 patients enrolled into the study, 54 were treated with at least one dose of sorafenib. Partial response was observed in one patient (2%) and stable disease in 20 patients (37%); no complete responses were observed. Disease stabilization for greater than or equal to 16 weeks was seen in 12 patients (22%); stabilization for greater than or equal to 6 months in seven patients (13%). The most common drug-related grade 3 adverse events were rash/desquamation (6%), hand-foot skin reaction (4%), and fatigue (4%). Baseline vascular endothelial growth factor levels, levels of soluble epidermal growth factor receptor during treatment and both baseline and changes in soluble human epidermal growth factor receptor 2 levels correlated significantly with clinical outcomes. Although the primary endpoint of overall response rate showed minimal improvement on sorafenib 400 mg twice-daily treatment, the rate of disease stabilization was encouraging in patients treated with one or more lines of chemotherapy. The treatment had a clinically manageable toxicity profile. Further investigation of single-agent sorafenib in this patient population is not recommended; however, studies investigating combinations of sorafenib with chemotherapeutic agents are warranted and ongoing.

A phase I trial of the oral, multikinase inhibitor sorafenib in combination with carboplatin and paclitaxel.

PURPOSE: This study evaluated the safety, maximum tolerated dose, pharmacokinetics, and antitumor activity of sorafenib, a multikinase inhibitor, combined with paclitaxel and carboplatin in patients with solid tumors. PATIENTS AND METHODS: Thirty-nine patients with advanced cancer (24 with melanoma) received oral sorafenib 100, 200, or 400 mg twice daily on days 2 to 19 of a 21-day cycle. All patients received carboplatin corresponding to AUC6 and 225 mg/m(2) paclitaxel on day 1. Pharmacokinetic analyses were done for sorafenib on days 2 and 19 of cycle 1 and for paclitaxel on day 1 of cycles 1 and 2. Pretreatment tumor samples from 17 melanoma patients were analyzed for BRAF mutations. RESULTS: Sorafenib was well tolerated at the doses evaluated. The most frequent severe adverse events were hematologic toxicities (grade 3 or 4 in 33 patients, 85%). Twenty-seven (69%) patients had sorafenib-related adverse events, the most frequent of which were dermatologic events (26 patients, 67%). Exposure to paclitaxel was not altered by intervening treatment with sorafenib. Treatment with sorafenib, paclitaxel, and carboplatin resulted in one complete response and nine partial responses, all among patients with melanoma. There was no correlation between BRAF mutational status and treatment responses in patients with melanoma. CONCLUSIONS: The recommended phase II doses are oral 400 mg twice daily sorafenib, carboplatin at an AUC6 dose, and 225 mg/m(2) paclitaxel. The tumor responses observed with this combined regimen in patients with melanoma warrant further investigation.

Phase I trial of sorafenib in combination with gefitinib in patients with refractory or recurrent non-small cell lung cancer.

PURPOSE: To evaluate the combination of sorafenib and gefitinib in patients with advanced non-small cell lung cancer. EXPERIMENTAL DESIGN: In this dose-escalation trial, patients received oral sorafenib (200-400 mg) twice daily with gefitinib (250 mg orally) once daily to identify the recommended dose for phase II trials (RDP; part A). The pharmacokinetics of the RDP were characterized further in additional patients (part B) receiving single-agent gefitinib or sorafenib for 21 days followed by a 7-day washout with crossover to the other agent for an additional 21 days. Patients then received the combination of sorafenib plus gefitinib in 28-day cycles. Safety, pharmacokinetics, and antitumor efficacy were evaluated. Potential drug-drug interactions and the relationship between pharmacokinetics and toxicity were also assessed. RESULTS: Thirty-one patients were treated (n=12, part A; n=19, part B). Most adverse events were grade 1/2. The most frequent grade 3/4 events included diarrhea and elevated alanine aminotransferase (both 9.7%). One dose-limiting toxicity occurred (part A: elevated alanine aminotransferase at 400 mg twice daily). Gefitinib had no effect on sorafenib pharmacokinetics. However, gefitinib C(max) (26%) and area under the curve (38%) were reduced by concomitant sorafenib. One patient had a partial response; 20 (65%; n=8, part A; n=12, part B) had stable disease >or=4 months. The RDP was sorafenib 400 mg twice daily with gefitinib 250 mg once daily. CONCLUSIONS: Sorafenib combined with gefitinib is well tolerated, with promising efficacy in patients with advanced non-small cell lung cancer. Studies to further investigate the significance of the reduction in gefitinib exposure by sorafenib are warranted.

Phase I trial of BAY 50-4798, an interleukin-2-specific agonist in advanced melanoma and renal cancer.

PURPOSE: BAY 50-4798 is an analogue of interleukin-2 that selectively activates T cells over natural killer cells. This phase I study was designed to determine the maximum tolerated dose (MTD) and safety of BAY 50-4798, screen for tumor response, and assess pharmacokinetics. EXPERIMENTAL DESIGN: Forty-five patients with metastatic melanoma or renal cancer were enrolled, 31 on escalating doses to determine the MTD, with 20 renal cell carcinoma patients treated at MTD to detect antitumor activity. BAY 50-4798 was delivered i.v. every 8 h, days 1 to 5 and 15 to 19, and could be repeated after 9 weeks if tumor was stable or responding. RESULTS: The MTD was defined by and reported in terms of doses received. The doses tested ranged from 1.3 to 26.1 microg/kg, and the MTD was defined as 10.4 microg/kg based on toxicities similar to those of aldesleukin. Two patients achieved partial responses, one with melanoma and one with renal cell carcinoma. Among all 45 patients, 53% and 9% experienced a grade 3 and 4 toxicity, respectively. Among the patients treated at the MTD of 10.4 microg/kg, 71% and 10% experienced a grade 3 and 4 toxicity, respectively. Pharmacokinetics showed dose-dependent peak concentrations (C(max)) and area under the curve with a half-life of approximately 2 h and no evidence of accumulation. Lymphocyte subset analysis confirmed the preferential expansion of T-cell subsets over natural killer cells. CONCLUSIONS: The antitumor activity of BAY 50-4798 in malignancies that respond to high-dose interleukin-2 was low. BAY 50-4798 might provide advantages over aldesleukin in antigen-specific immunotherapies.

Phase I targeted combination trial of sorafenib and erlotinib in patients with advanced solid tumors.

PURPOSE: Sorafenib and erlotinib are potent, orally administered receptor tyrosine kinase inhibitors with antiproliferative and antiangiogenic activities. Given their inhibitory target profile and efficacy as single agents, the combination of these drugs is of considerable interest in solid malignancies. This study aimed to determine the recommended phase II dose of this targeted combination, their toxicity profile, pharmacokinetic interaction, and preliminary clinical activities. EXPERIMENTAL DESIGN: Sorafenib was administered alone for a 1-week run-in period, and then both drugs were given together continuously, with every 28 days considered as a cycle. Three dose levels were assessed. RESULTS: Seventeen patients with advanced solid tumors received 75 cycles of treatment. The most frequent adverse events of all grades were constitutional and gastrointestinal in nature followed by electrolytes and dermatologic toxicities. Fatigue was the most common adverse event (17 patients; 100%) followed by diarrhea (15 patients; 88%), hypophosphatemia (13 patients; 76%), and acneiform rash (12 patients; 71%). These adverse events were predominantly mild to moderate. The recommended phase II dose of this combination was determined as 400 mg twice daily sorafenib and 150 mg daily erlotinib. Pharmacokinetic analysis revealed no significant effect of erlotinib on the pharmacokinetic profile of sorafenib. Among 15 evaluable patients, 3 (20%) achieved a confirmed partial response and 9 (60%) had stable disease as best response. CONCLUSIONS: Sorafenib and erlotinib are well tolerated and seem to have no pharmacokinetic interactions when administered in combination at their full single-agent recommended doses. This well tolerated combination resulted in promising activity that needs further validation in phase II studies.

Phase I trial of sorafenib and gemcitabine in advanced solid tumors with an expanded cohort in advanced pancreatic cancer.

BACKGROUND: With its potent inhibitory effects against Raf-1 kinase and vascular endothelial growth factor receptor-2, sorafenib is a novel oral anticancer agent targeting signal transduction and angiogenic pathways. This study is designed to combine sorafenib and gemcitabine due to their compatibility in preclinical models and nonoverlapping clinical toxicities. EXPERIMENTAL DESIGN: An initial dose-escalation part of the study enrolled patients with advanced solid tumors, followed by an expanded cohort at the recommended dose for patients with advanced unresectable or metastatic pancreatic cancer. Sorafenib is administered continuously, whereas gemcitabine is given at 1,000 mg/m2 weekly x 7 followed by 1 rest week, then weekly x 3 every 4 weeks. RESULTS: Forty-two patients have been enrolled overall, including 19 in the dose-escalation part and 23 in the extended pancreatic cancer cohort. Demographics were as follows: male-to-female ratio = 26:16; median age = 61 years (range 39-83 years); Eastern Cooperative Oncology Group performance status 0:1:2 ratio = 16:21:5. The recommended dose of this combination is sorafenib 400 mg twice daily and gemcitabine 1,000 mg/m2. The most frequent grade 3 or 4 adverse events of all causalities were thrombocytopenia (28.6%), lymphopenia (21.4%), lipase elevation (19%), neutropenia (16.7%), and fatigue (14.3%). Antitumor activity was observed in both groups, with 2 (10.5%) confirmed partial responses in ovarian cancer and 12 patients (63.2%) with disease stabilization in the dose-escalation part; 13 patients (56.5%) achieved disease stabilization in the pancreatic cohort. There was no consistent pharmacokinetic drug-to-drug interaction between sorafenib and gemcitabine. CONCLUSIONS: Sorafenib and gemcitabine are well tolerated in combination; further evaluations in pancreatic and ovarian cancers are warranted.

Lack of effect of ketoconazole-mediated CYP3A inhibition on sorafenib clinical pharmacokinetics.

Sorafenib is a novel, small-molecule anticancer compound that inhibits tumor cell proliferation by targeting Raf in the Raf/MEK/ERK signalling pathway, and inhibits angiogenesis by targeting tyrosine kinases such as vascular-endothelial growth factor receptor (VEGFR-2 and VEGFR-3) and platelet-derived growth factor receptor (PDGFR). In vitro microsomal data indicate that sorafenib is metabolized by two pathways: phase I oxidation mediated by cytochrome P450 (CYP) 3A4; and phase II conjugation mediated by UGT1A9. Approximately 50% of an orally administered dose is recovered as unchanged drug in the feces, due to either biliary excretion or lack of absorption. The aim of this study was to evaluate the effect of CYP3A inhibition by ketoconazole on sorafenib pharmacokinetics. This was an open-label, non-randomized, 2-period, one-way crossover study in sixteen healthy male subjects. A single 50 mg dose of sorafenib was administered alone (period 1) and in combination with ketoconazole 400 mg once daily (period 2) (ketoconazole was given for 7 days, and a single 50 mg sorafenib dose was administered concomitantly on day 4). No clinically relevant change in pharmacokinetics of sorafenib and no clinically relevant adverse events or laboratory abnormalities were observed in this study upon co-administration of the two drugs. Plasma concentrations of the main CYP3A4 generated metabolite, sorafenib N-oxide, decreased considerably upon ketoconazole co-administration. This effect is in accordance with the in vitro finding that CYP3A4 is the primary enzyme for sorafenib N-oxide formation. Further, these data indicate that blocking sorafenib metabolism by the CYP3A4 pathway will not lead to an increase in sorafenib exposure. This is consistent with data from a clinical mass-balance study that showed 15% of the administered dose was eliminated by glucuronidation, compared to less than 5% eliminated as oxidative metabolites. Since there was no increase in sorafenib exposure following concomitant administration of the highly potent CYP3A4 inhibitor ketoconazole with low dose sorafenib, it is postulated that higher therapeutic doses of sorafenib may be safely co-administered with ketoconazole, as well as with other inhibitors of CYP3A.

Safety and pharmacokinetics of the dual action Raf kinase and vascular endothelial growth factor receptor inhibitor, BAY 43-9006, in patients with advanced, refractory solid tumors.

PURPOSE: BAY 43-9006, a novel multikinase inhibitor, prevents tumor growth by combining two antitumor activities: inhibition of both tumor cell proliferation and tumor angiogenesis. This phase I, open-label, nonrandomized, noncontrolled, single-arm, dose escalation study was done to determine the maximum tolerated dose (MTD), safety profile, pharmacokinetic variables, effect on biomarkers, and tumor response with BAY 43-9006 in 19 patients with advanced, refractory solid tumors. EXPERIMENTAL DESIGN: BAY 43-9006 was given orally in repeated cycles of 1-week on/1-week off. The study comprised five dose levels, ranging from 100 mg twice daily (bid) to 800 mg bid. Treatment of each patient continued until unacceptable toxicity, tumor progression, or death. RESULTS: Rash and hypertension were the dose-limiting toxicities at the 800 mg bid dose requiring study drug discontinuation; therefore, the MTD of BAY 43-9006 in this study was determined to be 600 mg bid. BAY 43-9006 was generally well tolerated, with mild to moderate toxicities. Pharmacokinetic analysis showed early absorption followed by delayed secondary peaks and slow terminal elimination. Stable disease was achieved in five patients: one patient showed reduced tumor activity (positron emission tomography scan) and reduced mitogen-activated protein kinase signaling (lower phospho-ERK); one patient remained on treatment until study end point. CONCLUSIONS: The results confirm the favorable safety profile of BAY 43-9006 and support the development of this compound for the treatment of solid tumors.

Biomarkers and surrogate endpoints: how and when might they impact drug development?

As the pharmaceutical industry starts developing novel molecules developed based on molecular biology principles and a better understanding of the human genome, it becomes increasingly important to develop early indicators of activity and/or toxicity. Biomarkers are measurements based on molecular pharmacology and/or pathophysiology of the disease being evaluated that may assist with decision-making in various phases of drug development. The utility of biomarkers in the development of drugs is described in this review. Additionally, the utility of pharmacokinetic data in drug development is described. Development of biomarkers may help reduce the cost of drug development by allowing key decisions earlier in the drug development process. Additionally, biomarkers may be used to select patients who have a high likelihood of benefit or they could be used by clinicians to evaluate the potential for efficacy after start of treatment.

Pentostatin pharmacokinetics and dosing recommendations in patients with mild renal impairment.

PURPOSE: The purpose of this study was to determine the pharmacokinetic parameters of pentostatin in renally impaired patients in order to establish dosing guidelines for this population. METHODS: Pentostatin doses were administered as 15-min intravenous infusions to patients based on their measured creatinine clearance (CLcr) as follows. Patients with normal renal function (NRF), defined as CLcr >60 ml/min, received 4 mg/m(2) repeated every14 days. Patients with impaired renal function (IRF) included those with CLcr 41-60 ml/min who received 3 mg/m(2) and those with CLcr 21-40 ml/min who received 2 mg/m(2), also repeated every 14 days. Heparinized plasma samples were collected during drug infusion and out through 96 h after dosing, except in two patients in whom sampling was extended to 144 h after dosing. Urine sampling extended to 96 h after dosing, and all samples were analyzed by a validated enzyme immunoassay for pentostatin concentrations. RESULTS: Enrolled in the study were 13 patients (7 IRF and 6 NRF), of whom 12 contributed samples for pharmacokinetic analysis. Median baseline CLcr values were 71.5 ml/min for NRF patients and 44 ml/min for IRF patients. Following the end of intravenous infusion, pentostatin plasma concentrations declined biexponentially with time. In some patients there was a transient increase in pentostatin equivalents 2 to 4 h after dosing. There was a good correlation between measured CLcr and pentostatin total plasma clearance. The AUC(0- infinity ) values seen in IRF patients, at lower doses, were within the range of the AUC(0- infinity ) values seen in patients with normal CLcr. Toxicities observed in the two groups of patients were similar. CONCLUSIONS: The pentostatin doses used in the study appear to be appropriate for administration to cancer patients with varying degrees of renal impairment.

Plasma biomarkers as predictors of outcome in patients with advanced hepatocellular carcinoma.

PURPOSE: Validated biomarkers of prognosis and response to drug have not been identified for patients with hepatocellular carcinoma (HCC). One of the objectives of the phase III, randomized, controlled Sorafenib HCC Assessment Randomized Protocol (SHARP) trial was to explore the ability of plasma biomarkers to predict prognosis and therapeutic efficacy. EXPERIMENTAL DESIGN: In SHARP, 602 patients with advanced HCC were randomized to receive either oral sorafenib 400 mg twice a day per os or matching placebo daily on a continuous basis. Ten plasma biomarkers implicated in the pathogenesis of HCC were measured in 491 patients at baseline and in 305 after 12 weeks of treatment. The candidate biomarkers were analyzed to identify correlates of prognosis or predictors of response to sorafenib. RESULTS: In both the entire patient population and the placebo cohort, baseline angiopoietin 2 (Ang2) and VEGF concentrations independently predicted survival. Clinical variables such as macroscopic vascular invasion, Eastern Cooperative Oncology Group (ECOG) performance status, and baseline α-fetoprotein and alkaline phosphatase concentrations also independently predicted survival in these groups. In the sorafenib cohort, trends toward enhanced survival benefit from sorafenib were observed in patients with high s-c-KIT or low hepatocyte growth factor concentration at baseline (P of interaction = 0.081 and 0.073, respectively). CONCLUSIONS: The angiogenesis biomarkers Ang2 and VEGF were independent predictors of survival in patients with advanced HCC. In contrast, none of the biomarkers tested significantly predicted response to sorafenib.

Phase I trial to investigate the safety, pharmacokinetics and efficacy of sorafenib combined with docetaxel in patients with advanced refractory solid tumours.

AIM: The safety, pharmacokinetics and efficacy of sorafenib plus docetaxel in patients with advanced refractory cancer were investigated in a phase I, dose-escalation trial. METHODS: Twenty-seven patients in four cohorts received docetaxel on day 1 (cohorts 1 and 4: 75 mg/m2; cohorts 2 and 3: 100 mg/m2) plus sorafenib on days 2-19 (cohorts 1 and 2: 200 mg twice-daily (bid); cohorts 3 and 4: 400 mg bid) in 21-day cycles. RESULTS: Most common adverse events (AEs) (grade 3-5) included neutropenia (89%), leucopaenia (81%), hand-foot skin reaction (30%) and fatigue (30%). The most common drug-related AEs leading to dose reduction/interruption or permanent discontinuation were dermatologic (41%), gastrointestinal (26%) and constitutional (22%). Coadministration of sorafenib altered the pharmacokinetics of docetaxel. On average, docetaxel area under the concentration-time curve (AUC)(0-24) increased by 5% (cohort 1), 54% (cohort 2), 36% (Cohort 3) and 80% (cohort 4) with docetaxel plus sorafenib, while C(max) increased by 16-32%, independent of sorafenib/docetaxel doses. Three of 25 evaluable patients (11%) had partial responses; 14 (52%) had stable disease. CONCLUSION: Dose-limiting dermatologic AEs were more common than expected for either therapy alone. A starting dose of docetaxel 75 mg/m2 plus sorafenib 400mg bid (with dose reductions for dermatological toxicities) is proposed for phase II.

Pharmacokinetic results of a phase I trial of sorafenib in combination with dacarbazine in patients with advanced solid tumors.

PURPOSE: Sorafenib, a multikinase inhibitor of Raf and several growth factor receptors, is under investigation in combination with dacarbazine, a commonly used chemotherapeutic agent for the treatment of many cancers. The current phase I study investigates the effects of sorafenib on the pharmacokinetic (PK) profile of dacarbazine and its metabolite 5-amino-imidazole-4-carboxamide (AIC). (AIC is formed in amounts equimolar to the active alkylating moiety, methane diazohydroxide, which is undetectable by known validated assays.) METHODS: Patients with advanced solid tumors received intravenous dacarbazine 1,000 mg/m(2) on day 1 of a 21-day cycle to evaluate the PK of dacarbazine alone. Sorafenib 400 mg was administered twice daily continuously starting at day 2 of cycle 1. The PK of dacarbazine in the presence of sorafenib was assessed on day 1 of cycle 2. Sorafenib PK was also assessed at steady state. RESULTS: PK data were available for 15 of 23 patients. With concomitant administration of sorafenib, the mean AUC and C (max) values of dacarbazine were reduced by 23 and 16%, respectively. Mean AUC and C (max) values of AIC were increased by 41 and 45%, respectively, with individual increases of up to 106 and 136%, respectively. The apparent terminal half-lives of the two compounds were not significantly influenced by sorafenib. Based on coefficients of variation, the AUC and C (max) values for sorafenib and its three metabolites were highly variable with dacarbazine coadministration. CONCLUSIONS: Concomitant administration of sorafenib and dacarbazine as described above may result in decreased dacarbazine exposure but increased AIC exposure.

Interaction of sorafenib and cytochrome P450 isoenzymes in patients with advanced melanoma: a phase I/II pharmacokinetic interaction study.

BACKGROUND: In vitro data indicate that the sorafenib is a moderate inhibitor of cytochrome P450 (CYP) enzymes, including CYP3A4, CYP2C19, and CYP2D6. This phase I/II study in patients with advanced melanoma evaluated the potential effect of sorafenib on the pharmacokinetics of midazolam, omeprazole, and dextromethorphan, specific substrates of CYP3A4, CYP2C19, and CYP2D6, respectively. METHODS: Twenty-one patients received sorafenib 400 mg twice daily for 28 consecutive days. On days 1 and 28, a cocktail containing midazolam 2 mg, omeprazole 20 mg, and dextromethorphan 30 mg was administered. Pharmacokinetic analyses were performed on day 1 without sorafenib and day 28 after steady-state sorafenib exposure; sorafenib pharmacokinetics were evaluated on day 28. We defined an interaction to be excluded if the 90% confidence interval of the ratio of all day 28:day 1 analyses fell within a range from 0.80 to 1.25. RESULTS: In all, 18 patients were evaluable. On day 28, area under the plasma concentration-time curve from time 0 to 12 h (AUC(0-12)) and maximum plasma concentration (C(max)) for sorafenib were 38.1 mg h/l and 4.9 mg/l, respectively. Day 28:day 1 ratios for AUC from time 0 extrapolated to infinity (AUC(0-inf)) and C(max) for midazolam were 0.85 and 0.98, respectively. Day 28:day 1 ratio for 5-OH-omeprazole:omeprazole plasma concentration at 3 h postdose was 1.26, slightly outside of the 0.80-1.25 range. Thus, an interaction could not be excluded, but is considered unlikely to be clinically significant. Day 28:day 1 ratio for dextromethorphan:dextrorphan concentration in urine was 0.94. Sorafenib had an acceptable safety profile. The most frequently observed grade 3-4 toxicities in cycle 1 included elevated lipase (19%) and hypertension (10%). CONCLUSIONS: In this patient population, our results demonstrate that exposures of probes of CYP3A4, CYP2D6, or CYP2C19 activity are potentially altered by administration of sorafenib at 400 mg twice daily. However, these differences are sufficiently small that a clinically significant inhibition or induction of these important drug metabolizing P450 isoenzymes is unlikely. Clinical and, where possible, drug level monitoring may still be appropriate for drugs of narrow therapeutic range co-administered with sorafenib.

Plasma biomarkers correlating with clinical outcome in a phase II study of sorafenib in advanced NSCLC.

We investigated the relationship between plasma protein biomarker concentrations and clinical outcomes in 52 patients with relapsed/refractory advanced non-small cell lung cancer (NSCLC) treated with 400~mg bid sorafenib in a phase II trial. Blood samples were collected at baseline, on day 15 of cycle 1 (C1D15), and on day 1 of cycle 3 (C3D1), and plasma concentrations of total VEGF, VEGF-165, soluble (s) VEGFR-2, PDGF-BB, sPDGFR-ß, sEGFR, sHER-2, uPA, PAI-1, uPAR, TIMP-1, and circulating Ras p21 were assayed by ELISA. Elevated baseline VEGF, VEGF-165, PDGF-BB, Ras p21, and TIMP-1 concentrations were associated with poorer patient outcomes (shorter overall survival [OS] and/or progression-free survival [PFS]). During treatment, the mean concentrations of sVEGFR-2, PDGF-BB, sPDGFR-ß, TIMP-1, uPAR, and PAI-1 decreased, while the mean sEGFR concentration increased. Increases in VEGF, VEGF-165, PDGF-BB, and TIMP-1 during treatment were associated with better outcomes (longer OS and/or PFS), whereas increases in plasma Ras p21 during treatment were associated with shorter PFS. The associations between baseline concentrations and/or pharmacodynamic changes in plasma proteins and clinical outcomes in NSCLC patients treated with sorafenib suggest that these biomarkers may have a prognostic role and/or predict the efficacy of sorafenib in patients with NSCLC.

Safety and Efficacy of Sorafenib in Patients with Hepatocellular Carcinoma (HCC) and Child-Pugh A versus B Cirrhosis.

BACKGROUND: We performed a retrospective analysis of data from a phase II study evaluating sorafenib in patients with advanced hepatocellular carcinoma (HCC) to assess differences in safety and efficacy based on Child-Pugh (CP) status (A/B). METHODS: Patients received sorafenib 400 mg PO bid. We analyzed safety, pharmacokinetic (PK), and efficacy data in the two CP groups. RESULTS: Ninety-eight patients were CP A; 38 were CP B, with a median duration of therapy of 4 and 1.8 months, respectively. Grade 3/4 adverse events in the CP A and B groups, respectively, included hyperbilirubinemia (14% and 53%), ascites (3% and 5%), and encephalopathy (3% and 13%). Median overall survival (OS) in the CP A group was 9.5 months, compared with 3.2 months in the CP B population. Responses were limited in both groups. AUC and C(max) values were comparable between the two groups. CONCLUSIONS: Due to the lack of randomization against placebo or no therapy in this study, it is unclear if the more frequent worsening of liver cirrhosis and outcome of CP B patients are drug related or due to disease progression, or both. As expected, outcome was poorer in patients with CP B than in those with CP A cirrhosis. The hyperbilirubinemia seen in both groups may be at least partly related to inhibition of UGT1A1 by sorafenib. PK profiles were similar in the two groups. More data are needed to confirm and more fully understand the safety and efficacy of sorafenib in patients with advanced HCC and CP B cirrhosis.

Safety and pharmacokinetics of sorafenib combined with capecitabine in patients with advanced solid tumors: results of a phase 1 trial.

Sorafenib (twice daily [bid]) plus capecitabine (2 weeks on schedule/1 week off schedule) safety and pharmacokinetics were investigated in patients with advanced solid tumors (N = 35). Cohort 1 (n = 13) included sorafenib 200 mg bid and capecitabine 1050 mg/m(2) bid; cohort 2 (n = 4), sorafenib 400 mg bid and capecitabine 1050 mg/m(2) bid; cohort 3 (n = 6), sorafenib 200 mg bid and capecitabine 1050 mg/m(2) bid (cycles 1 and 2), then 400 mg bid and capecitabine 1050 mg/m(2) bid (cycle 3 onwards); and cohort 4 (n = 12), sorafenib 400 mg bid and capecitabine 850 mg/m(2) bid. The combination of sorafenib and capecitabine was generally well tolerated. Most frequent drug-related adverse events were hand-foot skin reaction (HFSR, 89%), diarrhea (71%), and fatigue (69%). The HFSR was dose-limiting toxicities in 6 patients. Sorafenib exposure (C(max) and AUC(0-12)) was unaffected by concomitant capecitabine. Concomitant sorafenib moderately increased capecitabine and 5-fluorouracil (metabolite) exposure when the capecitabine dose was 1050 mg/m(2) bid. Simultaneous administration of 400 mg bid sorafenib and 850 mg/m(2) bid capecitabine, however, had only minor effects on the exposure to capecitabine and 5-fluorouracil. Based on the overall toxicity profile and pharmacokinetic parameters, the recommended phase 2 doses were therefore sorafenib 400 mg bid and capecitabine 850 mg/m(2) bid, as scheduled above.

Biomarkers predicting outcome in patients with advanced renal cell carcinoma: Results from sorafenib phase III Treatment Approaches in Renal Cancer Global Evaluation Trial.

PURPOSE: Plasma proteins [vascular endothelial growth factor (VEGF), soluble VEGF receptor 2 (sVEGFR-2), carbonic anhydrase IX (CAIX), tissue inhibitor of metalloproteinase 1 (TIMP-1), and Ras p21] and one tumor gene (VHL) were analyzed to identify prognostic biomarkers or indicators of response to sorafenib in a subset of patients enrolled in the Treatment Approaches in Renal Cancer Global Evaluation Trial. EXPERIMENTAL DESIGN: Nine hundred three patients with advanced renal cell carcinoma (RCC) were randomized to 400 mg sorafenib twice a day or placebo. Samples collected at baseline and after 3 and 12 weeks were subjected to enzyme-linked immunosorbent assays. VHL exons were sequenced from tumor biopsies. RESULTS: Baseline biomarker data were available for VEGF (n = 712), sVEGFR-2 (n = 713), CAIX (n = 128), TIMP-1 (n = 123), Ras p21 (n = 125), and VHL mutational status (n = 134). Higher Eastern Cooperative Oncology Group performance status (ECOG PS) score correlated with elevated baseline VEGF (P < 0.0001) and a higher incidence of VHL mutations (P = 0.008), whereas higher Memorial Sloan-Kettering Cancer Center (MSKCC) score correlated with elevated VEGF (P < 0.0001), CAIX (P = 0.027), and TIMP-1 (P = 0.0001). Univariable analyses of baseline levels in the placebo cohort identified VEGF (P = 0.0024), CAIX (P = 0.034), TIMP-1 (P = 0.001), and Ras p21 (P = 0.016) as prognostic biomarkers for survival. TIMP-1 remained prognostic for survival in a multivariable analysis model (P = 0.002) that also included ECOG PS, MSKCC score, and the other biomarkers assayed. In the placebo cohort, TIMP-1 (P < 0.001) and Ras p21 (P = 0.048) levels increased at 12 weeks. In the sorafenib cohort, VEGF levels increased at 3 and 12 weeks of treatment (both weeks P < 0.0001), whereas sVEGFR-2 (both weeks P < 0.0001) and TIMP-1 levels (P = 0.002, week 3; P = 0.006, week 12) decreased. CONCLUSIONS: VEGF, CAIX, TIMP-1, and Ras p21 levels were prognostic for survival in RCC patients. Of these, TIMP-1 has emerged as being independently prognostic.

Recovery of microarray-quality RNA from frozen EDTA blood samples.

INTRODUCTION: The availability of blood collection systems with RNA stabilizing additives (e.g. PAXgene) has opened the field for gene expression profiling in large multi-center clinical trials. Here, we investigated whether the PAXgene system also offers a method for extraction of RNA from frozen EDTA blood samples, which do not yield RNA of high enough quality for RNA expression profiling, when extracted with standard protocols. METHODS: Whole blood was obtained from six healthy volunteers in conventional EDTA tubes and frozen. The thawed EDTA blood was transferred into PAXgene tubes, and the RNA was extracted using the PAXgene RNA extraction kit. Microarray analysis was performed to asses the effect of RNA quality on gene expression profiles. RESULTS: The RNA yield of the transferred samples was 1.76+/-0.88 microg/ml. This yield was clearly lower than the yield from a PAXgene reference group (2.84+/-0.62 microg/ml), but considerably higher than the yield resulting from a standard protocol usually applied to fresh EDTA blood samples (0.07+/-0.06 microg/ml). The RNA integrity number (RIN) of the transferred samples was 6.1+/-0.8 as compared to 9.8+/-0.1 for the PAXgene reference. Microarray analysis of the extracted RNA suggested that samples with RIN values above 5 produce data that fulfill the quality criteria defined by the manufacturer. DISCUSSION: The transfer of thawed EDTA blood into PAXgene blood collection tubes offers a method to recover sufficient RNA of acceptable quality for microarray experiments.