Gemcitabine in Combination with a Second Cytotoxic Agent in the First-Line Treatment of Locally Advanced or Metastatic Pancreatic Cancer: a Systematic Review and Meta-Analysis

BACKGROUND

It remains controversial whether the addition of a second cytotoxic agent can further improve the therapeutic effect of gemcitabine monotherapy in advanced or metastatic pancreatic cancer (LA/MPC).

OBJECTIVE

The objective of the present systematic review and meta-analysis was to investigate the efficacy and safety of gemcitabine-based doublet chemotherapy regimens compared to single-agent gemcitabine in the first-line treatment of unresectable LA/MPC.

METHODS

We searched for randomized controlled trials (RCTs) of gemcitabine monotherapy versus gemcitabine in combination with a second cytotoxic agent in patients with LA/MPC. The last search date was December 31, 2016.

RESULTS

Twenty-seven RCTs were identified and included in the present systematic review and meta-analysis, involving a total of 7343 patients. The meta-analysis showed that gemcitabine-based combination therapy significantly improved overall survival (OS) (HR: 0.89; 95% confidence interval (CI): 0.85-0.94; P < 0.0001), progression-free survival (PFS) (HR: 0.80; 95% CI: 0.73-0.88; P < 0.0001), and overall response rate (ORR) (RR: 1.83; 95% CI: 1.62-2.07; P < 0.0001) in comparison to single-agent gemcitabine. Subgroup analysis suggested that the antitumor activity differed between gemcitabine-based combination regimens: doublet regimens of gemcitabine plus a taxoid, and gemcitabine plus a fluoropyrimidine, in particular an oral fluoropyrimidine, resulted in a significant OS benefit for the patients. However, the combination of gemcitabine with other cytotoxic agents, such as platinum compounds or topoisomerase inhibitors failed to reduce the mortality risk. Combination therapy caused more grade 3/4 toxicities, including neutropenia, thrombocytopenia, vomiting, diarrhea, and fatigue.

CONCLUSIONS

Gemcitabine-based doublet regimens demonstrated superiority over gemcitabine monotherapy in overall efficacy, but were associated with increased toxicity. Different gemcitabine-based combinations showed different antitumor activity, and doublet regimens of gemcitabine in combination with a taxoid or a fluoropyrimidine, in particular an oral fluoropyrimidine provided significant survival benefits in the first-line treatment of unresectable LA/MPC.

Use of gemcitabine as a second-line treatment following chemotherapy with folfirinox for metastatic pancreatic adenocarcinoma

There is a lack of prospective data about second-line treatments for metastatic pancreatic ductal adenocarcinoma patients. This is partially due to recent changes in first-line chemotherapy treatments. Despite this dearth of information, 50.0% of the patients who experience failure with first-line folinic acid, 5-fluorouracil, irinotecan and oxaliplatin (folfirinox) treatment are eligible for additional chemotherapy. In this setting, gemcitabine is widely used without any standard recommendations available. The present study evaluated 42 patients who received gemcitabine subsequent to a first-line treatment of folfirinox between January 2008 and December 2012 at the Centre Léon Bérard (Lyon, France). Clinical data, biological data and tumor characteristics were retrospectively analyzed to identify prognostic factors for successful treatment with gemcitabine. In total, 11 patients (26.2%) experienced control of their cancer with gemcitabine treatment. However, there was no predictive marker for their response to the drug. The median overall survival was 3.6 months from gemcitabine initiation [95% confidence interval (CI), 2.1-5.1]. The median length of gemcitabine treatment was 1.5 months (95% CI, 0.3-13.3). Among the 11 patients who were successfully treated with gemcitabine, 6 were resistant to first-line folfirinox treatment. Patients who were non responsive to folfirinox had a higher probability of success with gemcitabine compared with patients that responded to folfirinox (54.5 vs. 21.4%, respectively; P=0.061). The present study did not identify any clinical or biological marker with a predictive value for successful gemcitabine treatment. Furthermore, successful gemcitabine treatment was not correlated with patients' response to first-line folfirinox treatment. This suggests an absence of cross-resistance in the chemotherapy protocols and provides evidence for effective cancer treatment with the second-line gemcitabine therapy.