Response to GEMOX plus erlotinib in pancreatic cancer is associated with ERCC1 overexpression

There are no data about the efficacy of gemcitabine in combination with oxaliplatin (GEMOX) and erlotinib for the treatment of metastatic pancreatic cancer (mPC). Thus, we performed this retrospective analysis in mPC patients to investigate the activity and safety of GEMOX plus erlotinib and correlated the benefit with ERCC1 expression, a potential biomarker for treatment response.

Patients with untreated mPC receiving off-protocol GEMOX plus erlotinib were included. Data collection included baseline demographic, response and toxicity data as well as PFS and OS. Additionally, immunohistochemistry was performed to stain for ERCC1 expression.

A total of 51 patients were included. The median age was 62 years and the median ECOG performance score was 1 (range, 0-1). Objective response or disease stabilization was achieved in 54% of the patients. The median PFS was 4·4 months (95% CI 4·4-5·4) and median OS was 8·5 months (95% CI 6·1-10·9). The 27 patients, who benefited from this regimen, had a median PFS of 6·7, a median OS of 11·2 months and an overexpression of ERCC1 (histoscore 10, P ≤ 0·05) compared to nonresponders (histoscore 7·2). Myelosuppression was the most frequent side effect. The most common severe nonhematological toxicities were diarrhoea and skin toxicity in six (12%) patients each.

These data suggest that the combination of GEMOX plus erlotinib is safe and active in about half of the patients. Patients, who had a higher ERCC1 staining pattern, benefited most from this therapy. Prospective biomarker studies are warranted to confirm these findings.