Bevacizumab Combined with S-1 and Raltitrexed for Patients with Metastatic Colorectal Cancer Refractory to Standard Therapies: A Phase II Study

LESSONS LEARNED

Bevacizumab combined with S-1 and raltitrexed demonstrated positive antitumor efficacy and acceptable toxicity. This combination might represent a treatment option for refractory metastatic colorectal cancer.

BACKGROUND

In patients with metastatic colorectal cancer (mCRC) refractory to standard therapies, S-1 plus raltitrexed showed a good objective response rate (ORR) and significant survival benefit in our previous study. In the present study, we assessed the activity and safety of bevacizumab combined with S-1 and raltitrexed.

METHODS

This investigator-initiated, open-label, single-arm, phase II trial was performed at West China Hospital in China. Patients with mCRC who had disease progression after fluoropyrimidine, irinotecan, and oxaliplatin and had at least one measurable lesion were eligible for this trial. Anti-epidermal growth factor receptor (EGFR) (for tumors with wild-type RAS) and anti-vascular endothelial growth factor (VEGF) therapy in the first or second line was allowed, but patients who had been treated with bevacizumab across two consecutive chemotherapy regimens were excluded. Patients received bevacizumab (7.5 mg/kg on day 1), oral S-1 (80-120 mg per day for 14 days), and raltitrexed (3 mg/m² on day 1) every 3 weeks. The primary endpoint was ORR. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity.

RESULTS

From September 2015 to November 2019, 44 patients were enrolled. Tumor response evaluation was available in 44 patients at the time of the analysis. There were no complete responses; the ORR was 15.9%, and the disease control rate was 54.5%. Median PFS and OS were 110 days (95% confidence interval [CI], 65.0-155.0) and 367 days (95% CI, 310.4-423.6), respectively. The combination was well tolerated.

CONCLUSION

Bevacizumab combined with S-1 and raltitrexed showed promising antitumor activity and safety in refractory mCRC.

Dose-escalation strategy in refractory metastatic colorectal cancer: A change in terms of cost-effectiveness

The analysis was conducted to assess the pharmacological costs of regorafenib and trifluridine/tipiracil in the treatment of refractory metastatic colorectal cancer (mCRC). Pivotal phase III randomized controlled trials (RCTs) of regorafenib and trifluridine/tipiracil in the treatment of refractory mCRC were considered. We have also considered the ReDOS trial, in order to verify if the dose-escalation strategy (practice changing for regorafenib) could influences the results. Differences in OS (expressed in months) between the different arms were calculated and compared with the pharmacological costs (at the Pharmacy of our Hospital and expressed in euros (€)) needed to get one month of OS. Trifluridine/tipiracil resulted the less expensive, with 1167.50 €per month OS-gained. The ReDOS trial further reduce costs with 510.41 €per month OS-gained in favour of regorafenib with the escalation-dose strategy. Both regorafenib and trifluridine/tipiracil can be considered economically sustainable treatments for refractory mCRC, apparently with a lower cost of trifluridine/tipiracil. The adoption of a dose-escalation strategy (ReDOS trial) could reverse the situation making regorafenib more cost-effective than trifluridine/tipiracil.

Regorafenib, TAS-102, or fruquintinib for metastatic colorectal cancer: any difference in randomized trials?

PURPOSE

Direct randomized comparisons of regorafenib, TAS-102, and fruquintinib for treating metastatic colorectal cancer (mCRC) are lacking. Here, we evaluated the efficacy and safety of three agents by a systematic review and a network meta-analysis.

METHODS

We included phase III randomized controlled trials in the PubMed, Embase, and Scopus Cochrane databases and ClinicalTrials.gov registry from initiation until January 2019. Data from randomized controlled trials including overall survival (OS), progression-free survival (PFS), and adverse events (AEs) were extracted. Direct meta-analysis and indirect meta-analysis using network meta-analysis were assessed.

RESULTS

Five trials comprising a total of 2586 patients were included. For efficacy analysis of OS, no statistically significant differences were observed between regorafenib and TAS-102 (HR 0.945, 95% CI [0.677, 1.320], P = 0.753), regorafenib and fruquintinib (HR 1.056, 95% CI [0.690, 1.621], P = 0.814), or TAS-102 and fruquintinib (HR 1.117, 95% CI [0.740, 1.685], P = 0.610). However, fruquintinib was superior in PFS compared with TAS-102 (HR 1.756, 95% CI [1.079, 2.857], P = 0.023). Regorafenib and TAS-102 appeared to have a similar effect on PFS (HR 0.907, 95% CI [0.611, 1.346], P = 0.641), as did regorafenib and fruquintinib (HR 1.592, 95% CI [0.968, 2.618], P = 0.067). None of the three agents were better in terms of all grade AEs or any grade of 3-5 AEs. However, subgroup analysis of AEs exhibited different toxicity profiles between the three drugs.

CONCLUSIONS

Indirect comparison suggested that the three agents had similar OS but that fruquintinib was superior in terms of PFS compared with that of TAS-102. These three agents had different toxicity profiles.

A Systematic Review and Network Meta-Analysis of Regorafenib and TAS-102 in Refractory Metastatic Colorectal Cancer

BACKGROUND

Regorafenib at different dosing strategies and TAS-102 are treatment options for refractory metastatic colorectal cancer (mCRC). We aimed to evaluate the comparative effectiveness evidence supporting these different strategies.

MATERIALS AND METHODS

We searched different databases for randomized controlled trials evaluating TAS-102 or regorafenib in patients with refractory mCRC who failed prior oxaliplatin, irinotecan, and fluoropyrimidine. Outcomes of interest included overall survival (OS) and progression-free survival (PFS). The overall effect was pooled using the DerSimonian random effects model. We conducted network meta-analysis based on White's multivariate meta-regression to pool evidence from direct and indirect comparisons.

RESULTS

Six trials at low risk of bias (2,445 patients) were included. Direct comparisons showed that Rego 160 and TAS-102 as monotherapy were superior to best-supportive care (BSC) in terms of PFS (Rego 160: hazard ratio [HR], 0.4; 95% confidence ratio [CI], 0.26-0.63; TAS-102: HR, 0.46 CI, 0.40-0.52) and OS (Rego 160: HR, 0.67; CI, 0.48-0.93; TAS-102: HR, 0.67; CI, 0.57-0.80). Network analysis showed no statistically difference in PFS or OS between Rego 160 and TAS-102. Rego 80+ was superior to BSC in terms of OS (HR, 0.44; CI, 0.23-0.84) and PFS (HR, 0.37; CI, 0.21-0.66). Rego 80+ was associated with statistically nonsignificant improvement in OS and PFS compared with TAS-102 and Rego 160.

CONCLUSION

Regorafenib 160 and TAS-102 appear to have similar efficacy. Rego 80+ is shown to be superior to BSC. A trend for improved OS was observed with Rego 80+ versus Rego 160 or TAS 102.

IMPLICATIONS FOR PRACTICE

Regorafenib at a dose of 160 mg and TAS-102 appear to have similar efficacy in patients with refractory metastatic colorectal cancer. Regorafenib with a dose escalation strategy is superior to best-supportive care. Given its tolerability and the observed trend in survival benefit compared with regorafenib 160, dose escalation strategy of regorafenib (80+) may be the preferred option in this setting.