First-Line Treatment with Irinotecan and Raltitrexed in Metastatic Colorectal Cancer

A decade's overview of 2-aminothiophenes and their fused analogs as promising anticancer agents

Over the past decades, cancer has been a challenging domain for medicinal chemists as it is an international health concern. In association, small molecules such as 2-aminothiophenes and their derivatives showed significant antitumor activity through variable modes of action. Therefore, this article aims to review the advances regarding these core scaffolds over the past 10 years, where 2-aminothiophenes and their fused analogs are classified and discussed according to their biological activity and mode of action, in the interest of boosting new design pathways for medicinal chemists to develop targeted antitumor candidates.

First-line chemotherapy with raltitrexed in metastatic colorectal cancer: an Association des Gastro-entérologues Oncologues (AGEO) multicentre study

BACKGROUND

In case of contraindication or intolerance to fluoropyrimidines, raltitrexed is a validated alternative in metastatic colorectal cancer (mCRC), associated or not with oxaliplatin. Little is known about the outcomes of raltitrexed combined with irinotecan or targeted therapies.

METHODS

This retrospective multicentre study enroled mCRC patients treated with first-line raltitrexed-based chemotherapy. Treatment-related toxicities were recorded. Progression-free survival (PFS) and overall survival (OS) were calculated from treatment start.

RESULTS

75 patients were treated with raltitrexed alone, TOMOX, or TOMIRI with or without bevacizumab. Grade 3-4 adverse events were seen in 31% of patients, without significant difference between the different treatment schedules. amongst the 36 patients with a history of fluoropyrimidine-induced cardiac toxicity, none developed cardiovascular events on raltitrexed. Median PFS and OS were 10.6 (95% CI 8.2 - 13.1) and 27.4 months (95% CI 24.1-38.1), respectively. Considering the chemotherapy regimen, TOMOX was significantly associated with better PFS and OS compared to TOMIRI and raltitrexed alone.

CONCLUSIONS

In patients with mCRC not eligible for fluoropyrimidines, first-line raltitrexed-based chemotherapy had an acceptable safety profile. PFS and OS were consistent with usual survival data in mCRC, and significantly better in patients treated with TOMOX, independently of associated targeted therapies.

Biweekly Raltitrexed Combined With Irinotecan as Second-Line Therapy for Patients With Metastatic Colorectal Cancer: A Phase II Trial

Objective

Irinotecan-based doublet chemotherapy strategy was standard second-line backbone for patients with oxaliplatin-refractory metastatic colorectal cancer. The aim of this study was to evaluate tolerability and efficacy of raltitrexed combined with irinotecan biweekly administered as the second-line therapy for mCRC patients.

Methods

The study was a prospective, single-center, non-randomized, open-label phase II clinical trial. Patients with mCRC after failure with oxaliplatin and fluoropyrimidine or its derivatives were enrolled. Irinotecan (180 mg/m²) and raltitrexed (2.5 mg/m²) were given intravenously on day 1. Cycles were repeated every 2 weeks. The primary endpoint was progression-free survival (PFS), and the secondary endpoints included overall response rate (ORR), disease control rate (DCR), overall survival (OS), and adverse events (AEs).

Results

Between December 2012 and October 2016, 33 and 35 patients enrolled were assessed for response and safety, respectively. The ORR was 8.6%, and the DCR was 71.4%. The median PFS was 4.5 months (95% CI 3.8-5.2). The median OS was 12.0 months (95% CI 8.5-15.5). Four patients received conversion therapy to no evidence of disease (NED), and 2 patients were still alive with beyond 24 months survival. The most common grade 3/4 AEs were anorexia (14.3%), vomiting (14.3%), nausea (11.4%), fatigue (8.6%), and leukopenia (8.6%). No one died from treatment-related events. The incidence and severity of toxicity were irrelevant to UGT1A1 status.

Conclusions

The combination of irinotecan with raltitrexed is an efficient, convenient, and acceptable toxic regimen for second-line treatment for mCRC patients.

Clinical efficacy of irinotecan plus raltitrexed chemotherapy in refractory esophageal squamous cell cancer

Our retrospective study assessed the efficacy and safety of irinotecan plus raltitrexed in esophageal squamous cell cancer (ESCC) patients who were previously treated with multiple systemic therapies. Between January 2016 and December 2018, records of 38 ESCC patients who underwent irinotecan plus raltitrexed chemotherapy after at least one line of chemotherapy were reviewed. Efficacy assessment was performed every two cycles according to the RECIST version 1.1. A total of 95 cycles of chemotherapy were administered, and the median course was 3 (range 2-6). There was no treatment-related death. Nine patients had partial response, 21 had stable disease and eight had progressive disease. The overall objective response rate was 23.68% (9/38) and the disease control rate was78.94% (30/38). After a median follow-up of 18.5 months, the median progression-free survival and overall survival were 105 and 221 days, respectively. There were five patients (13.15%) with grade 3/4 leukopenia, three patients (7.89%) with grade 3/4 neutropenia and one patient (2.63%) with grade 3/4 diarrhea. The combination of irinotecan plus raltitrexed was effective for pretreated ESCC patients. Further studies are needed to determine the optimal dose of the two drugs.

Real-world Safety and Efficacy of Raltitrexed in Patients With Metastatic Colorectal Cancer

BACKGROUND

Use of fluoropyrimidine-based therapy in patients with metastatic colorectal cancer is associated with significant toxicities. This study aimed to assess the safety and efficacy of raltitrexed use in patients with metastatic colorectal cancer who developed significant toxicities after fluoropyrimidine-based treatment.

PATIENTS AND METHODS

We identified patients with metastatic colorectal cancer who were treated with raltitrexed-based systemic therapy after developing serious adverse events with fluoropyrimidine-based treatment in a large Canadian province from 2004 to 2018. Demographic, tumor, and treatment characteristics were retrieved from the electronic medical records. Progression-free and overall survival were assessed from the start of raltitrexed-based therapy.

RESULTS

A total of 86 patients were identified for the study. The median age was 66.5 years, and 58.1% of patients were men. The primary cancer site was right, left, and transverse colon in 38.4%, 27.9%, and 9.3%, respectively. The remaining 24.4% had rectal cancer. Among all patients, 43.0% had received more than 2 prior systemic therapies, and 37.6% had developed previous cardiotoxicity to fluoropyrimidine-based treatment. The median progression-free and overall survival were 8.5 and 10.2 months, respectively. On multivariable Cox regression model, patients with left-sided colon cancer (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.12-0.97; P = .044) and the Eastern Cooperative Oncology Group performance status of 0/1 (HR, 0.10; 95% CI, 0.01-0.82; P = .032) had a longer progression-free survival, whereas left-sidedness of colon cancer was the only factor that predicted overall survival (HR, 0.30; 95% CI, 0.10-0.88; P = .029). Raltitrexed was well-tolerated with common adverse events that included anemia in 41.7% of patients and chemotherapy-induced nausea and vomiting in 27.4%. Most toxicities were grade 1/2, but 16.7% of patients experienced grade 3. There were no cardiac events and treatment-related deaths.

CONCLUSIONS

Raltitrexed in patients with colorectal cancer who were previously treated with fluoropyrimidine-based systemic therapy is effective and well-tolerated.

A systematic review of raltitrexed-based first-line chemotherapy in advanced colorectal cancer

Raltitrexed is a thymidylate synthase inhibitor belonging to the antimetabolite class of cytotoxic drugs. It is also effective in colorectal cancer (CRC) both as a single agent and in combination with other drugs, in particular in those patients with cardiologic risk factors or previous cardiotoxicity. The efficacy of first-line raltitrexed-based chemotherapy containing oxaliplatin (TOMOX) and irinotecan (TOMIRI) was investigated in this systematic review. Studies that enrolled advanced CRC patients for first-line therapy with TOMOX/TOMIRI combinations were identified using electronic databases (Pubmed, SCOPUS, Web of Science, EMBASE, and the Cochrane Library). A systematic analysis was carried out using Comprehensive Meta Analysis (version 2.2.064) software to calculate the pooled response rate and 95% confidence limits. The median pooled overall survival and progression-free survival were also calculated. Results for TOMOX and TOMIRI studies were compared using the two-sided Student's t-test. We tested for significant heterogeneity using Cochran's χ-test and I index. Twelve studies published between 2001 and 2012 were eligible for this analysis and a total of 735 patients were enrolled in these studies. The overall response rate was 40% (95% confidence interval 34-46%): 43.9% for TOMOX and 34.1% for TOMIRI arms. The weighted median overall survival and progression-free survival times were 14.6 and 6.7 months, respectively. Neutropenia and liver toxicity were more frequent with TOMOX, whereas neutropenia and diarrhea were more frequent with TOMIRI. However, compared with historical FOLFOX and FOLFIRI trials, raltitrexed-based doublets are associated with less neutropenia and gastrointestinal toxicity and uncommon cardiotoxicity. TOMOX and TOMIRI doublets are active as first-line chemotherapy for advanced CRC and seem useful in particular when the use of 5-fluorouracil is contraindicated for cardiac comorbidity.

Targeting thymidylate synthase in colorectal cancer: critical re-evaluation and emerging therapeutic role of raltitrexed

INTRODUCTION

5-fluorouracil continues to be the cornerstone of treatment for colorectal cancer. Although fluoropyrimidines are generally considered as well-tolerated drugs, severe toxicities can be a major clinical problem, and the recommended prolonged infusion of 5-fluorouracil provokes discomfort in patients. Raltitrexed (Tomudex), a quinazoline analogue of folinic acid, is a selective and direct thymidylate synthase (TS) inhibitor with a convenient 3-weekly schedule of administration.

AREAS COVERED

In this review, through critical insight into the mechanism of action and main clinical experiences, the authors suggest the necessity to reconsider raltitrexed as a valuable anticancer drug and as a suitable option for colorectal cancer. The authors highlight its emerging therapeutic role in clinical practice for patients with fluoropyrimidine-induced cardiotoxicity or a significant history of cardiac disease.

EXPERT OPINION

This review discusses if TS could still be a relevant target for colorectal cancer in the era of molecular therapy and if raltitrexed should still be considered a drug with a life-threatening toxicity. Furthermore, this review discusses the principal combination clinical experiences of raltitrexed and its emerging therapeutic role in clinical practice as a suitable option for colorectal cancer patients with fluoropyrimidine-induced cardiotoxicity or a significant history of cardiac disease.

Irinotecan, oxaliplatin and raltitrexed for the treatment of advanced colorectal cancer

Out of every 17-18 individuals in the US, one develops colorectal cancer (CRC) in their lifetime. Of individuals diagnosed with CRC, > 50% present or develop metastatic disease, which, if untreated, is associated with 6-9 months median survival. Although surgical resection is the primary treatment modality for CRC, chemotherapy is the mainstay of treatment for metastatic or unresectable disease. For nearly three decades, 5-fluorouracil (5-FU) has been the chemotherapy of choice for treatment of CRC. However, the response rates to single 5-FU therapy have been suboptimal with an objective tumour response of 10-20%. Attempts have been made to improve the efficacy of 5-FU by either schedule alteration (protracted infusion versus intravenous push) or biochemical modulation with leucovorin (LV). Continuous infusion induced more tumour regression and prolonged the time-to-disease progression with some significant impact on survival (11.3 versus 12.1 months; p < 0.04). 5-FU/LV resulted in a significant increase in overall response rates and in the prolongation of disease-free survival in the adjuvant setting, although severe toxicities represent a major clinical problem. The last 10 years have seen the addition of several new agents such as irinotecan, oxaliplatin, raltitrexed, bevacizumab and cetuximab. The prognosis has significantly improved with the addition of these agents, with median survivals now > 20 months. This review paper focuses on irinotecan, oxaliplatin and raltitrexed when used alone and in combination.