A phase I study of capecitabine, oxaliplatin, and lapatinib in metastatic or advanced solid tumors

Metastatic colorectal cancer (mCRC) is a leading cause of cancer-related mortality in the United States, and new treatment options are needed. This phase I study investigated a novel regimen combining 2 chemotherapy drugs with proven efficacy in mCRC (capecitabine and oxaliplatin) with a tyrosine kinase inhibitor (lapatinib). Lapatinib has already been approved by the US Food and Drug Administration for treatment of selected cases of breast cancer.

Patients with solid tumors responsive to fluoropyrimidines or oxaliplatin were eligible for enrollment. Treatment was given over a 21-day cycle with a fixed dosing of intravenous oxaliplatin of 130 mg/m(2) on day 1. Capecitabine and lapatinib were given orally at escalating doses, starting at capecitabine 1500 mg/m(2)/day on days 1-14 and lapatinib 1000 mg daily on days 1-21.

Ten patients received treatment per study protocol. All had received previous systemic treatment. Diarrhea was one of the most common side effects and accounted for nearly all grade 3/4 toxicity. The starting dose level was determined to be the maximum tolerated dose. One patient with pancreatic cancer had evidence of a partial response. Three other patients demonstrated stable disease. There were no complete responses.

Results of this study suggest the regimen of capecitabine, oxaliplatin, and lapatinib has some efficacy in types of advanced or metastatic solid malignancies with known responsiveness to fluoropyrimidines or oxaliplatin. Further research may help determine whether this regimen can improve on the response rates seen with current standard regimens for mCRC.