Phase I clinical trial of irinotecan with oral capecitabine in patients with gastrointestinal and other solid malignancies

A Phase I dose-finding study using an innovative sequential biweekly schedule of irinotecan followed 24 hours later by capecitabine

BACKGROUND

Irinotecan and capecitabine have a broad spectrum of activity in human malignancy and are synergistic in an animal model when irinotecan precedes capecitabine.

PATIENTS AND METHODS

A Phase I design of the combination of irinotecan IV Day 1 with capecitabine on Days 2-8 every 2 weeks was evaluated in 27 adult patients with solid tumors. Two sequential schema were used: Arm A fixed the dose of irinotecan at 100 mg/m(2) and escalated capecitabine in cohorts, and arm B fixed the dose of capecitabine at 750 mg/m(2) PO BID and escalated the dosage of irinotecan.

RESULTS

Neutropenia was dose limiting with nausea and diarrhea as the most common nonhematological toxicities. Significant interpatient variation in toxicity occurred despite uniform dosing. No Grade IV toxicities were encountered. Grade III toxicity occurred in first cycle in 15 percent (3/20) patients in arm A and 29 percent (2/7) of patients in arm B. All toxicities were reversible. Repetitive dosing was feasible with prolonged disease stabilization in 8 patients.

CONCLUSIONS

The suggested Phase II dose of this combination and schedule is irinotecan 100 mg/m(2) and capecitabine 1000 mg/m(2) BID. Some patients tolerated a capecitabine dose as high as 1250 mg/m(2) BID.

Pharmacokinetic and safety study of weekly irinotecan and oral capecitabine in patients with advanced solid cancers

BACKGROUND

Capecitabine and irinotecan have demonstrated in vitro synergistic anti-cancer activity, and both are substrates for carboxyl esterases (CES). We conducted a study to identify a safe dose and potential drug-drug interactions of this combination.

METHODS

This was an open-label phase I dose escalation trial. Irinotecan was given as a 30 min infusion on days 1 and 8, and capecitabine on days 1-14 of a 21-day cycle. Plasma for pharmacokinetic analyses was drawn on days 1 and 8.

RESULTS

Forty-seven patients with advanced solid tumors received 202 cycles of chemotherapy in 6 dose cohorts. At the highest dose tested, 1 of 3 patients developed fatal neutropenia and gram-negative sepsis. At dose level 5 (100/2000), 2 of 28 patients developed cycle 1 DLT-grade 3 diarrhea/vomiting, and grade 3 diarrhea. Responses were observed in 9 of 35 (5 of 9 ovarian cancer) evaluable patients. The AUC((0-last)) of irinotecan, SN-38G, and APC were similar on days 1 and 8. However, SN-38 T(max) was longer on Day 8 (0.88 h vs. 1.23 h, p = 0.012). While SN-38 AUC((0-last)) was lower on day 8 by 35%, this was not statistically significant (p = 0.123).

CONCLUSIONS

Capecitabine results in a significantly delayed conversion of irinotecan to SN-38, suggesting drug-drug interaction at the level of CES. This suggests caution should be used when irinotecan is combined with substrates of CES, and warrants further study. The combination of irinotecan and capecitabine is safe and well tolerated at 100/2000, and warrants further evaluation in ovarian and breast cancer.

Dose-Finding Phase I Clinical and Pharmacokinetic Study of Orally Administered Irinotecan in Patients with Advanced Solid Tumors

PURPOSE

The aim of this study was to determine the daily maximum tolerated dose (MTD) and the dose-limiting toxicity for the following administration schedules: oral irinotecan given over 14 days every 3 weeks (part I) and oral irinotecan administered concomitantly with capecitabine over 14 days every 3 weeks (part II). In total, 42 patients (17 male and 25 female) with solid tumors refractory to standard therapy entered the study.

EXPERIMENTAL DESIGN

Treatment in part I consisted of irinotecan administered orally as semisolid matrix capsules at doses of 25, 30, and 35 mg/m(2) once daily to confirm the MTD of our earlier study. In part II treatment, dose levels for irinotecan combined with capecitabine were 20/1,600, 25/1,600, 30/1,600, and 30/2,000 mg/m(2)/d.

RESULTS

The median number of cycles administered per patient was 2.0 (range, 1-12) in part I and 2.0 (range, 1-13) in study part II. Gastrointestinal toxicities (grade 3 nausea, grades 3 and 4 vomiting, and grades 3 and 4 diarrhea) were dose limiting in both parts of the study. There were no grade 3 or 4 hematologic toxicities. The MTD was 30 mg/m(2)/d for irinotecan single agent and 30/1,600 mg/m(2)/d for the combination with capecitabine. Absorption of irinotecan was rapid, and peak concentrations of irinotecan and metabolite SN-38 were reached within 0 to 3 and 1.5 to 4.0 hours, respectively.

CONCLUSIONS

In conclusion, oral irinotecan and capecitabine is feasible and well tolerated, and the recommended dose for phase II studies is 30/1,600 mg/m(2)/d administered daily for 14 days every 3 weeks.

A phase I/II and pharmacokinetic study of irinotecan in combination with capecitabine as first-line therapy for advanced colorectal cancer

PURPOSE

The aim of this study was to determine in patients with previously untreated advanced colorectal cancer the maximum tolerated dose (MTD) and safety profile of irinotecan in combination with capecitabine, to identify a recommended dose and to determine the response rate and time to disease progression. In addition, we aimed to explore the pharmacokinetic parameters of irinotecan and capecitabine when used in different sequences of administration, with irinotecan infusion either prior to or after the first intake of capecitabine.

PATIENTS AND METHODS

One hundred patients were included: 43 patients were recruited into an extended phase I trial of alternating escalation in dose of both drugs where irinotecan was administered intravenously (i.v) on day 1 after first intake of capecitabine taken from days 1-14 twice daily, with cycles repeated every 3 weeks. After the determination of recommended dose a further 57 patients were treated in a phase II evaluation with the reverse sequence of drugs on day 1. Pharmacokinetic analysis was performed in patients treated at the recommended dose in two cohorts of patients in which the sequence of the first administration of each drug was reversed.

RESULTS

The MTD of the combination was determined as irinotecan 300 mg/m2, with capecitabine 2000 mg/m2/day. Dose limiting toxicities were neutropenia and diarrhoea. The recommended dose is irinotecan intravenous (i.v.) 250 mg/m2 day 1 and capecitabine 2000 mg/m2/day days 1-14, every 3 weeks. Treatment was well tolerated, with diarrhoea the most common serious toxicity. Response rate in the phase II cohort was 42% [95% confidence interval (CI) 29% to 56%]. Median duration of response was 7.7 months (95% CI 7.5-8.9). Median time to progression was 8.3 months (95% CI 5.8-10). No significant effect on irinotecan pharmacokinetics was observed whatever the intake of capecitabine before or after irinotecan infusion. An effect of irinotecan on capecitabine and some capecitabine metabolites was observed, but irinotecan did not effect 5-fluorouracil (5-FU) pharmacokinetics.

CONCLUSIONS

Irinotecan in combination with capecitabine is a well tolerated regimen with an activity comparable to, but more convenient than, irinotecan-5-FU i.v. combinations in patients with previously untreated advanced colorectal cancer. The pharmacokinetic data suggest that the sequence of administration does not impact significantly on the metabolism of the two drugs.

Phase I and pharmacokinetic study of oral irinotecan given once daily for 5 days every 3 weeks in combination with capecitabine in patients with solid tumors

PURPOSE

To assess the maximum tolerated dose, dose-limiting toxicity, pharmacokinetics, and preliminary antitumor activity of oral irinotecan given in combination with capecitabine to patients with advanced, refractory solid tumors.

PATIENTS AND METHODS

Patients were treated from day 1 with irinotecan capsules given once daily for 5 consecutive days (50 to 60 mg/m2/d) concomitantly with capecitabine given twice daily for 14 consecutive days (800 to 1,000 mg/m2); cycles were repeated every 21 days.

RESULTS

Twenty-eight patients were enrolled and received 155 cycles of therapy (median, five cycles; range, one to 18 cycles). With irinotecan 60 mg/m2/d and capecitabine 2 x 800 mg/m2/d, grade 3 delayed diarrhea in combination with grade 2 nausea (despite maximal antiemetic support) and grade 3 anorexia and colitis, were the first-cycle dose-limiting toxicities in two of six patients, respectively. At the recommended doses (irinotecan 50 mg/m2/d; capecitabine 2 x 1,000 mg/m2/d), side effects were mostly mild to moderate and uniformly reversible. Pharmacokinetic analysis showed that there was no interaction between oral irinotecan and capecitabine, and that body-surface area was not significantly contributing to the observed pharmacokinetic variability. Confirmed partial responses were observed in two patients with gallbladder carcinoma and in one patient with melanoma. Disease stabilization was noted in 16 patients.

CONCLUSION

The recommended phase II doses for oral irinotecan and capecitabine are 50 mg/m2/d for 5 consecutive days, and 2 x 1,000 mg/m2/d for 14 consecutive days repeated every 3 weeks, respectively.

Systemic therapy for colorectal cancer: focus on newer chemotherapy and novel agents

Systemic therapy for metastatic colorectal cancer is evolving rapidly after many years without significant change. Standard adjuvant therapy for rectal cancer, on the other hand, remains much the same as it has been since the early 1990s. Recent additions to the colorectal cancer armamentarium include capecitabine, irinotecan, and oxaliplatin. Use of these agents in metastatic colorectal cancer and potential for use in localized rectal cancer are discussed. In addition to these "classical" chemotherapeutic agents, there are a number of exciting therapies designed to target specific molecular features of malignant cells. These agents are now being tested in colorectal cancer in addition to chemotherapy and to radiotherapy, with the hope that improvements in outcome will be made without substantial increases in treatment toxicity. The focus of the section on newer classes of agents will be on agents that are in phase II and III trials, with brief mention of other exciting treatment strategies.