Docetaxel and capecitabine for previously treated metastatic colorectal cancer

Abstract

13579 Background: Docetaxel (D) induces human colon cancer cell lines to upregulate thymidine phosphorylase, an enzyme which activates capecitabine (C) to its cytotoxic form. This provided rationale for adding low dose D to C in patients with colorectal cancer (CRC). Although this combination has been established in metastatic breast cancer, it has not been evaluated in CRC. Because of concerns of toxicity in a pretreated population, we performed a phase I trial in patients with previously treated CRC. Methods: Eligibility: At least 1 prior treatment for metastatic disease; ECOG PS 0–1; adequate organ function. Design: Phase I, dose escalation. D, IV, days 1 & 8, and C, PO BID days 5–18, repeated q21days. Dose Level 1: D=15mg/m2, C=1000mg/m2; Level 2: D= 15 mg/m2, C= 1100 mg/m2; Level 3: D= 20 mg/m2, C= 1100 mg/m2; Level 4: D=20mg/m2, C=1250mg/m2. Results: 13 patients have thus far been treated. 11 are evaluable for toxicity and 10 for response (1 at dose level 4 was taken off study due to non-compliance before completion of cycle 1; another died of progressive cancer before completing cycle 1 at dose level 4; another is evaluable for toxicity but not yet for response). 9 with colon, 4 with rectal primary sites. Median follow-up= 5 mo (1–19 mo). Med age= 59 (30–75); #prior regimens for met disease 1–2, all of which were 5-FU based. Toxicities No dose limiting toxicities (DLT) until Dose Level 4. Dose Level 1: 1/3 developed grade 2 diarrhea and hand-foot syndrome and delayed grade 3 hand-foot; Dose Level 2: 2/3 developed grade 2 toxicities (hand-foot in one and diarrhea in the other); Dose Level 3: 1/3 developed delayed grade 2 hand-foot; Dose Level 4: 1 patient with delayed grade 2 hand-foot and grade 1 eye tearing; another developed DLT (grade 4 stomatitis/dehydration). Response 6/10 patients progressed after 2 cycles; 2 pts had stable disease, one lasting 4.6 mo; 2 patients had a partial response, one of which lasted 9 mo. The latter case had refractory disease to FOLFOX 4 but a 78% reduction in her liver metastases to D+C. Conclusions: The combination of low dose docetaxel, used as chemosensitizing agent, with capecitabine in this pretreated group of patients with metastatic CRC appears to be well tolerated, with no DLTs seen until Dose Level 4, and has modest activity. MTD determination awaits further accrual. No significant financial relationships to disclose.