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.

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.

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.

A phase I and pharmacokinetic study of the selective, non-peptidic inhibitor of matrix metalloproteinase BAY 12-9566 in combination with etoposide and carboplatin.

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that degrade the extracellular matrix during the processes of invasion, metastasis and angiogenesis. BAY 12-9566 (BAY) is a selective, non-peptidic biphenyl inhibitor of MMPs, with nanomolar inhibitory activity against MMP-2, -3 and -9, and anti-invasive, anti-metastatic and anti-angiogenic activity in a variety of tumor models. This phase I study of oral BAY was conducted to evaluate the safety and pharmacokinetics of BAY when administered in combination with etoposide (VP-16) or in combination with VP-16 and carboplatin (CBDCA) in subjects with advanced cancer. The first cohort of patients (n=8) received a cycle of VP-16, 60 mg/m, followed 1 week later by a fixed daily oral dose of BAY, 800 mg b.i.d., to which three potential possible doses of VP-16 (low dose: 60 mg/m; mid dose: 90 mg/m; high dose: 120 mg/m) were added every 3 weeks as tolerated. The second cohort (n=5) received VP-16 (120 mg/m) and CBDCA (AUC=5) followed 1 week later by a fixed daily oral dose of BAY (800 mg) b.i.d., to which VP-16 (120 mg/m) and CBDCA (AUC=5) were added. Dose-limiting toxicity (DLT) was defined as toxicity grade 3 or above. Maximum tolerated dose was declared if two or more patients experienced DLT. A performance status of 0-2 and acceptable organ function were required for eligibility. Plasma concentrations of BAY and VP-16 were measured to investigate pharmacokinetic interactions. Eight eligible patients with a variety of tumor types (median age 64 years, range 44-76) were enrolled in the first cohort, six of who whom completed all three levels of VP-16. Progressive disease occurred in five of the eight patients; three patients continued on study with treatment. Drug level and pharmacokinetics analysis of BAY and VP-16 were also determined. The combination of BAY and VP-16 was tolerable in the first cohort, permitting enrollment of the second cohort. In the second cohort (n=5), the combination of BAY, VP-16 and CDBCA was intolerable at the doses used due to excessive hematologic toxicity in the first five patients enrolled. Pharmacokinetics and toxicity analysis was performed for this group of patients. Only Level 1 of treatment was completed for Cohort II. At this point the study was halted due to toxicity and the results of an interim analysis that failed to demonstrate sufficient clinical activity of this compound in other clinical trials. We conclude that the combination of BAY and VP-16 was well tolerated. However, the combination of BAY, VP-16 and CDBCA produces significant hematologic toxicity. Findings from this study may help to direct further studies with other inhibitors of MMPs.