Could Panitumumab with very low dose Capecitabine be an option as a maintenance regimen.

Abstract

Background: Anti-epidermal growth factor receptor therapy showed an overall median survival improvement in wild type Ras metastatic colorectal cancer. Maintenance with anti EGFR in metastatic colorectal cancer wild type Ras was studied in many trials with promising results and many of these trials gave combined chemo with the target therapy and this combination had shown benefit in the form of synergistic effect and in delaying the resistance to the anti EGFR.

Method: In our study patients received 6 cycles of 5-FU based chemotherapy with Panitumumab and patients who had partial response, complete response or stationary disease received metronomic Capecitabine with Panitumumab every 2 weeks for one year. The primary end point was progression free survival (PFS) and the secondary end points were safety, toxicity and overall survival (OS).

Results: The median PFS for all patients was 18 ± 1.4 months and the median OS was 45 months. Patients with synchronous metastasis and those who received Oxaliplatin based regimen with Panitumumab were found to have longer PFS compared to those with metachronous metastasis or those who received other chemotherapy regimen with accepted toxicity profile to the maintenance therapy.

Conclusion: Using Panitumumab with metronomic Capecitabine is considered an accepted maintenance regimen in wild type Ras metastatic colorectal cancer regardless of the primary site.