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.

Role of gemcitabine-based combination therapy in the management of advanced pancreatic cancer: a meta-analysis of randomised trials

BACKGROUND

Pancreatic cancer is the fourth leading cause of cancer-related death worldwide. Gemcitabine is the mainstay treatment for advanced disease. However, almost all up-to-date trials, that evaluated the benefit of gemcitabine-combination schedules, failed to demonstrate an improvement in overall survival (OS). In this study, we performed a systematic review and a meta-analysis of randomised clinical trials (RCTs) to investigate the efficacy and safety of gemcitabine-based combination regimens as compared to gemcitabine alone in the management of pancreatic cancer.

METHODS

Clinical trials were collected by searching different databases (PubMed, Embase and the Central Registry of Controlled Trials of the Cochrane Library) and abstracts from major cancer meetings. We considered period ranging from January 1997 to January 2012. Primary end-point was OS, secondary end-points were response rate (RR), disease control rate (DCR) and safety. Hazard ratios (HRs) of OS, odds-ratios (ORs) of RR, DCR and risk ratios of grade 3-4 toxicity rates (TRs), were extracted as presented in retrieved studies and used for statistical analysis. Meta-analytic estimates were derived using random-effects model.

FINDINGS

Thirty-four trials for a total of 10,660 patients were selected and included in the final analysis. The analysis showed that combination chemotherapy confers benefit in terms of OS (HR: 0.93; 95% confidence interval (CI): 0.89-0.97; p=0.001). ORs for both RR and DCR demonstrated a significant advantage for combination therapy (OR for RR: 0.60, 95%CI: 0.47-0.76, p<0.001; OR for DCR: 0.79; 95%CI: 0.66-0.93; p=0.006). Toxicities were more frequent with the combination treatment and significance in terms of risk ratio was reached for diarrhoea (0.53, 95%CI: 0.36-0.79), nausea (0.74, 95%CI: 0.56-0.96), neutropenia (0.71, 95%CI: 0.59-0.85) and thrombocytopenia (0.57, 95%CI: 0.43-0.75).

INTERPRETATION

The combination chemotherapy as compared to gemcitabine alone significantly improves OS in advanced pancreatic cancer (APC). However, this advantage is marginal whereas the treatment-related toxicity is increased, suggesting the use of gemcitabine-based combination regimens only in selected patient populations. New prospective trials, based on translational approaches and innovative validated biomarkers, are eagerly awaited on this topic.

A multicentre randomised phase II trial of gemcitabine alone vs gemcitabine and S-1 combination therapy in advanced pancreatic cancer: GEMSAP study

Background:

This randomised phase II trial compared gemcitabine alone vs gemcitabine and S-1 combination therapy in advanced pancreatic cancer.

Methods:

Patients were randomly assigned to 4-week treatment with gemcitabine alone (1000, mg m⁻² gemcitabine by 30-min infusion on days 1, 8, and 15) or gemcitabine and S-1 combination therapy (1000, mg m⁻² gemcitabine by 30-min infusion on days 1 and 15 and 40 mg m⁻² S-1 orally twice daily on days 1–15). The primary end point was progression-free survival (PFS).

Results:

Between July 2006 and February 2009, 106 patients were enrolled. The PFS in gemcitabine and S-1 combination arm was significantly longer than in gemcitabine arm (5.4 vs 3.6 months), with a hazard ratio of 0.64 (P=0.036). Overall survival (OS) for gemcitabine and S-1 combination was longer than that for gemcitabine monotherapy (13.5 vs 8.8 months), with a hazard ratio of 0.72 (P=0.104). Overall, grade 3 or 4 adverse events were similar in both arms.

Conclusion:

Gemcitabine and S-1 combination therapy demonstrated longer PFS in advanced pancreatic cancer. Improved OS duration of 4.7 months was found for gemcitabine and S-1 combination therapy, though this was not statistically significant.