Re: Irinotecan-related cholinergic syndrome induced by coadministration of oxaliplatin

Dose escalation of CPT-11 in combination with oxaliplatin using an every two weeks schedule: a phase I study in advanced gastrointestinal cancer patients

BACKGROUND

To determine the dose-limiting toxicity of CPT-11 in combination with oxaliplatin, and the maximal tolerated dose (MTD) and the recommended dose (RD) of CPT-11 using an every two weeks schedule.

PATIENTS AND METHODS

The study was designed to evaluate escalated doses of CPT-11 starting at 100 mg/m2 with a fixed clinically-relevant dose of 85 mg/m2 oxaliplatin given every two weeks.

RESULTS

Twenty-three patients and 186 cycles were evaluable for toxicity (median per patient: 7, range: 1-13). Grade 3 oxaliplatin-induced neurotoxicity was cumulative and limiting in 39% (9 of 23) of patients. The MTD of CPT-11 was 200 mg/m2, with incomplete neutrophil recovery at day 15 as limiting toxicity. At the RD (175 mg/m2 of CPT-11): no grade 4 neutropenia was seen in the two first cycles; 30% of patients experienced grade 3-4 diarrhea. Febrile neutropenia (3.2% of all cycles) was 3-fold more frequent in performance status (PS) 2 than in PS0-1 patients. Among eleven colorectal cancer (CRC) patients, three complete and four partial responses were documented, including in three 5-fluorouracil (5-FU) refractory patients.

CONCLUSION

To combine CPT-11 175 mg/m2 and oxaliplatin 85 mg/m2 every two weeks is feasible in an outpatient setting, and very active in 5-FU resistant CRC patients. A dose of 150 mg/m2 CPT-11 is recommended in PS2 patients.

Combination of oxaliplatin plus irinotecan in patients with gastrointestinal tumors: results of two independent phase I studies with pharmacokinetics

PURPOSE

Two phase I studies of the oxaliplatin and irinotecan combination were performed in advanced gastrointestinal cancer patients to characterize the safety and pharmacokinetics of the regimen.

PATIENTS AND METHODS

Patients with a performance status (PS) of < or = 2 and normal hematologic, hepatic, and renal functions received oxaliplatin (2-hour intravenous infusion) followed 1 hour later by irinotecan administered over a 30-minute period, every 3 weeks. Dose levels that were explored ranged from 85 to 110 mg/m(2) for oxaliplatin and 150 to 250 mg/m(2) for irinotecan. Plasma pharmacokinetics of total and ultrafiltrable platinum, irinotecan, SN-38, and its glucuronide, SN-38G, were determined.

RESULTS

Thirty-nine patients with gastrointestinal carcinomas (24 with colorectal cancer [CRC], four with pancreas cancer, four with gastric cancer, three with hepatocarcinoma, and four with other) received 216 treatment cycles. Median age was 54 years (range, 21 to 72 years); 95% had PS of 0 to 1; all but six had failed fluorouracil (5-FU) chemotherapy. The maximum-tolerated dose was oxaliplatin 110 mg/m(2) plus irinotecan 200 mg/m(2) in one study and oxaliplatin 110 mg/m(2) plus irinotecan 250 mg/m(2) in the other study. Grade 3 to 4 diarrhea and febrile neutropenia were dose-limiting toxicities; other toxicities included emesis and dose-cumulative neuropathy. Recommended dose for phase II studies is oxaliplatin 85 mg/m(2) and irinotecan 200 mg/m(2). At this dose (12 patients, 65 cycles), grade 3 and 4 toxicities per patient included the following: emesis in 42% of patients, neutropenia in 33% (febrile episodes in 17%), peripheral neuropathy in 25%, delayed diarrhea in 17%, and thrombocytopenia in 8%. Two patients with Gilbert's syndrome experienced severe irinotecan toxicity. No plasmatic pharmacokinetic interactions were detected. Seven partial responses were observed in 24 CRC patients.

CONCLUSION

This combination is feasible, with activity in 5-FU-resistant CRC patients. Phase I studies that explore the every-2-weeks schedule, in addition to phase II studies of this schedule (as well as in combination with 5-FU) as second-line therapy of metastatic CRC, are ongoing.