Sorafenib administered using a high-dose, pulsatile regimen in patients with advanced solid malignancies: a phase I exposure escalation study.

BACKGROUND: (Pre)clinical evidence is accumulating that intermittent exposure to increased doses of protein kinase inhibitors may improve their treatment benefit. In this phase I trial, the safety of high-dose, pulsatile sorafenib was studied. PATIENTS AND METHODS: High-dose sorafenib was administered once weekly in exposure escalation cohorts according to a 3 + 3 design. Drug monitoring was performed in weeks 1-3 and doses were adjusted to achieve a predefined target plasma area under the curve (AUC)(0-12 h). The effect of low gastric pH on improving sorafenib exposure was investigated by intake of the acidic beverage cola. RESULTS: Seventeen patients with advanced malignancies without standard treatment options were included. Once weekly, high-dose sorafenib exposure was escalated up to a target AUC(0-12 h) of 125-150 mg/L/h, achieving a twofold higher Cmax compared to standard continuous dosing. Dose-limiting toxicity was observed in three patients: grade 3 duodenal perforation (2800 mg sorafenib), grade 5 multiorgan failure (2800 mg sorafenib) and grade 5 biliary tract perforation (3600 mg sorafenib). The mean difference between observed and target AUC(0-12 h) was 45% (SD ± 56%) in week 1 using a fixed starting dose of sorafenib compared to 2% (SD ± 32%) in week 3 as a result of drug monitoring (P = 0.06). Dissolving sorafenib in cola, instead of water, did not improve sorafenib exposure. Clinical benefit with stable disease as the best response was observed in two patients. CONCLUSION: Treatment with high-dose, once weekly sorafenib administration resulted in dose-limiting toxicity precluding dose escalation above the exposure cohort of 125-150 mg/L/h. Drug monitoring was a successful strategy to pursue a target exposure.

Dose selection of corifollitropin alfa by modeling and simulation in controlled ovarian stimulation.

In controlled ovarian stimulation (COS), a single subcutaneous dose of corifollitropin alfa is used to initiate and sustain multifollicular growth for 7 days. The objective of this study was to determine the optimal dose of corifollitropin alfa. A pharmacokinetic model was developed to describe the time profile of corifollitropin alfa concentrations. Multiple parameters reflecting ovarian response were included in a pharmacokinetic-pharmacodynamic (PK-PD) model framework. An early decline in serum inhibin B was shown to be a sensitive marker for COS failure. Simulations were performed to select the lowest corifollitropin alfa dose that would result in a minimal cancellation rate: 100 microg for a group of women weighing 60 kg. With these doses, the predicted mean number of oocytes per started COS cycle was similar in the two groups, i.e., 12.1 and 13.2, respectively. The selected doses were tested in prospective clinical trials and were proven to be adequate.

A dose-escalation study of indisulam in combination with capecitabine (Xeloda) in patients with solid tumours.

This dose escalation study was designed to determine the recommended dose of the multi-targeted cell cycle inhibitor indisulam in combination with capecitabine in patients with solid tumours and to evaluate the pharmacokinetics of the combination. Thirty-five patients were treated with indisulam on day 1 of each 21-day cycle. Capecitabine was administered two times daily (BID) on days 1-14. Plasma concentrations of indisulam, capecitabine and its three metabolites were determined for pharmacokinetic analysis. The main dose-limiting toxicity was myelosuppression. Hand/foot syndrome and stomatitis were the major non-haematological toxicities. The recommended dose was initially established at indisulam 700 mg m(-2) and capecitabine 1250 mg m(-2) BID. However, during cycle 2 the recommended dose was poorly tolerated in three patients. A dose of indisulam 500 mg m(-2) and capecitabine 1250 mg m(-2) BID proved to be safe at cycle 1 and 2 in nine additional patients. Indisulam pharmacokinetics during cycle 1 were consistent with pharmacokinetic data from phase I mono-therapy studies. However, exposure to indisulam was remarkably increased at cycle 2 due to a drug-drug interaction between capecitabine and indisulam. Partial response was confirmed in two patients, one with colon carcinoma and the other with pancreatic carcinoma. Seventeen patients had stable disease. Indisulam (700 mg m(-2)) in combination with capecitabine (1250 mg m(-2) BID) was well tolerated during the first cycle. A dose of indisulam 500 mg m(-2) and capecitabine 1250 mg m(-2) BID was considered safe in multiple treatment cycles. The higher incidence of toxicities observed during cycle 2 can be explained by a time-dependent pharmacokinetic drug-drug interaction.

PK/PD model of indisulam and capecitabine: interaction causes excessive myelosuppression.

The anticancer agent indisulam was evaluated in a dose-escalation study in combination with capecitabine. Severe myelotoxicity was observed after multiple treatment cycles. We hypothesized that capecitabine inhibits the synthesis of CYP2C9, which metabolizes indisulam. The objectives were to develop a pharmacokinetic/pharmacodynamic (PK/PD) model for the combination treatment and to estimate the impact of a drug-drug interaction on the safety of various dose levels. NONMEM was used to develop a PK/PD model, including the impact of capecitabine coadministration on indisulam pharmacokinetics. A simulation study was performed to evaluate the risk of dose-limiting neutropenia. A time-dependent pharmacokinetic drug-drug interaction resulted in increased exposure to indisulam and in increased myelotoxicity. The risk of dose-limiting neutropenia increased with treatment duration and with dose. The excessive myelosuppression after multiple cycles may be explained by a pharmacokinetic interaction between indisulam and capecitabine. The combination of 550 mg/m(2) indisulam and 1,250 mg/m(2) capecitabine twice daily was considered safe.

A phase I and pharmacokinetic study of indisulam in combination with carboplatin.

Indisulam (E7070) is an anticancer agent that is currently being evaluated in phase II clinical studies. A significant reduction in glutathione synthetase and glutathione reductase transcripts by indisulam provided a molecular basis for its combination with platinum agents. Indisulam demonstrated high anti-tumour activity in various preclinical cancer models. The objectives of this study were (1) to determine the recommended dose of indisulam in combination with carboplatin in patients with solid tumours and (2) to evaluate the pharmacokinetics of the combination. Patients with solid tumours were treated with indisulam in combination with carboplatin. Indisulam (350, 500, or 600 mg m(-2)) was given as a 1-hour intravenous infusion on day 1 and carboplatin (5 or 6 mg min ml(-1)) as an intravenous infusion over 30 min on day 2 of a three-weekly cycle. Sixteen patients received study treatment and were eligible. Thrombocytopenia was the major dose limiting toxicity followed by neutropenia. Both drugs contributed to the myelosuppressive effect of the combination. Indisulam 500 mg m(-2) in combination with carboplatin 6 mg min ml(-1) was identified not to cause dose limiting toxicity, but a delay of re-treatment by 1 week was required regularly to allow recovery from myelosuppression. The recommended dose and schedule for an envisaged phase II study in patients with non-small cell lung cancer is indisulam 500 mg m(-2) in combination with carboplatin 6 mg min ml(-1) repeated four-weekly. Patients who do not experience severe thrombocytopenia at cycle 1 will be permitted to receive an escalated dose of indisulam of 600 mg m(-2) from cycle 2 onwards.