Abstract B97: A phase II trial of low-dose multiagent chemotherapy with gemcitabine, taxotere, xeloda, and cisplatin (GTX-C) in subjects with metastatic pancreatic cancer

Abstract

Abstract Background: Triplet chemotherapy has been shown to delay the emergence of resistance and extend survival in patients with metastatic pancreatic adenocarcinoma. Four drug regimens, even at low doses, may further improve survival by simultaneously targeting multiple oncogenic pathways. Methods: A phase II study of GTX-C (capecitabine 500 mg bid on days 1-14, and the combination of gemcitabine 500 mg/m2 (10 mg/m2/min), taxotere 20 mg/m2 and cisplatin 20 mg/m2 on days 4 and 11) was initiated in newly diagnosed untreated metastatic pancreatic cancer patients. The primary endpoint was progression-free survival rate at 6 months and designed such that the regimen would be considered active if the 6-month PFS rate was >75% and inactive if < 50%. Results: Twenty-eight patients were enrolled. All patients were ECOG 0-1. Eighty-six percent of patients had evidence of liver metastases and 25% had biliary stents in place at time of study initiation. Median CA19-9 was 6,159 U/mL (37-154,323 U/mL). Median length of follow-up was 10.1 months. Grade 3/4 related adverse events included: nausea/vomiting (7%), transaminitis (10%), anemia (14%), thrombocytopenia (24%), and neutropenia (55%). However, febrile neutropenia occurred in only 3 patients (10%) and not until cycles 6, 14, and 15. PFS rate at 6 months was 74.2% (95% CI: 53.3% - 86.8%). The partial response (PR) rate was 50%, stable disease (SD) rate was 39% and the disease control rate (DCR) was 89%. CA19-9 declines of >80% occurred in 77% of patients with measurable levels. Estimated median PFS was 8.4 months (95% CI: 6.1-10.6 months) and OS was 12.9 months (95% CI: 10.0-NA months) as of 11/14/2013. Ten additional patients have been enrolled onto an expansion cohort in which the period off between cycles has been changed from 7 to 14 days. Conclusions: GTX-C is highly active and well-tolerated in patients with metastatic pancreatic cancer and should be tested in a larger, comparative study. Clinical trial information: NCT01459614. Citation Format: Dung Le, Daniel Laheru, Luis A. Diaz, Jr. A phase II trial of low-dose multiagent chemotherapy with gemcitabine, taxotere, xeloda, and cisplatin (GTX-C) in subjects with metastatic pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B97.