Safe administration of irinotecan, oxaliplatin and raltitrexed in a DPD-deficient patient with metastatic colon cancer

Metastatic colorectal cancer: Advances in the folate-fluoropyrimidine chemotherapy backbone

Notwithstanding recent treatment advances in metastatic colorectal cancer (mCRC), chemotherapy with a combination of a fluoropyrimidine and a folate agent, often 5-fluorouracil (5-FU) and leucovorin, remains the backbone of treatment regimens for the majority of patients with mCRC. This is despite a recent focus on molecular-targeted treatments and patient stratification according to mutational status or expression levels of specific genes. Intracellular folate concentration was discovered to be pivotal in the cytotoxic efficacy of 5-FU, paving the way to the current standard combination therapy approach. Subsequent discovery that systemic chemotherapy agents, such as irinotecan and oxaliplatin, can further increase the efficacy of 5-FU-based treatments led to the development of several combination chemotherapy regimens, including FOLFOX, FOLFIRI and FOLFOXIRI. Subsequent efforts to optimise 5-FU-based treatments have focused on 5-FU analogues, initially capecitabine and the combination drug tegafur/gimeracil/oteracil (S-1) and then TAS-102, which has recently been evaluated in phase 3 clinical trials for refractory colorectal cancer. Further approaches taken to improve the efficacy of 5-FU chemotherapy regimens have focused on optimising the route and dosing schedules and regulating folate metabolism. Pharmacokinetic variability caused by the requirement for metabolic conversion of leucovorin has been central to recent research, and the development of agents such as arfolitixorin which bypass the need for metabolic conversion remains promising for future therapeutic candidates. In this review, we summarise the evidence leading to the current treatment regimens employing 5-FU and leucovorin, focusing on recent approaches taken to optimise and refine treatments to improve clinical outcomes in patients with mCRC.

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.

Acute hyperammonemic encephalopathy after 5-fluorouracil based chemotherapy

5-Fluorouracil (5-FU) based chemotherapy has been commonly used to treat metastatic or advanced colon cancer as an adjuvant chemotherapy. Although the side effects of 5-FU such as gastrointestinal problems and neutropenia and thrombocytopenia are common, not many cases of 5-FU related encephalopathy are reported. Hyperammonemic encephalopathy is a rare central nervous system toxicity following 5-FU chemotherapy manifesting as altered mental status with elevated ammonia levels with no radiologic abnormality. We report one case of 5-FU induced hyperammonemic encephalopathy occurring after Folfox4 (oxaliplatin, folinic acid and 5-fluorouracil) chemotherapy in a colon cancer patient who presented with confused mental status soon after the chemotherapy and review the 5-FU related encephalopathy.

Personalizing colon cancer therapeutics: targeting old and new mechanisms of action

The use of pharmaceuticals for colon cancer treatment has been increasingly personalized, in part due to the development of new molecular tools. In this review, we discuss the old and new colon cancer chemotherapeutics, and the parameters that have been shown to be predictive of efficacy and safety of these chemotherapeutics. In addition, we discuss how alternate pharmaceuticals have been developed in light of a potential lack of response or resistance to a particular chemotherapeutic.

Tegafur-uracil is a safe alternative for the treatment of colorectal cancer in patients with partial dihydropyrimidine dehydrogenase deficiency: a proof of principle

OBJECTIVE

The objective of this study was to evaluate the safety of using tegafur-uracil (UFT) in colorectal cancer patients with partial dihydropyrimidine dehydrogenase (DPD) deficiency.

PATIENTS AND METHODS

The study included five colorectal cancer patients who presented with acute toxicity (grades 3 and 4) after being given the first cycle of chemotherapy using 5-fluorouracil. The DPD deficiency was confirmed by gene sequencing. After a full recovery from all side effects, we changed the regimen to UFT (300 mg/m(2)/day) associated with leucovorin (90 mg/day) for 21 days, with an empirical dose reduction of at least 10% in the first cycle.

RESULTS

We prospectively analysed 22 UFT cycles in 5 patients. We did not observe any episodes of grade 3 or 4 toxicity. The predominant toxicities were of grades 1 and 2 (nausea, vomiting and diarrhoea).

CONCLUSION

Here, we demonstrate a complete absence of severe toxicity in all patients and cycles analysed. We believe that UFT is a safe alternative for the treatment of patients with partial DPD deficiency.

A randomized phase II study to compare oxaliplatin plus 5-fluorouracil and leucovorin (FOLFOX4) versus oxaliplatin plus raltitrexed (TOMOX) as first-line chemotherapy for advanced colorectal cancer

INTRODUCTION

The aim of this study was to compare TOMOX versus FOLFOX4 as first-line treatment of advanced colorectal cancer (CRC).

MATERIALS AND METHODS

191 chemotherapy-naïve patients were randomized to receive TOMOX or FOLFOX4. Patients were evaluated every 3 months and chemotherapy was continued until disease progression or unacceptable toxicity. Overall response rate was the primary endpoint.

RESULTS

183 patients were included in the intent-to-treat analysis (92 TOMOX and 91 FOLFOX4). Overall response rate was 45.6 and 36.3 % (p = 0.003) for TOMOX and FOLFOX4, respectively. No statistically significant differences were observed in overall survival (15.6 and 17.2 months; p = 0.475); progression-free survival (7.7 and 8.7 months; p = 0.292), and response duration (6.4 and 7.6 months; p = 0.372) for TOMOX and FOLFOX4, respectively. Grades 3 and 4 neutropenia (p < 0.0001) and leukopenia (p = 0.028) were more common with the FOLFOX4 regimen, while hepatic disorders and asthenia were higher in TOMOX group (p = ns). There were two treatment-related deaths in the FOLFOX4 arm and one in the TOMOX arm. Quality of life analysis based on the SF-36 revealed differences between the two regimens for physical and mental composite scores after 6 weeks, and for body pain and emotional role functioning after 6 and 12 weeks; all of these favored the FOLFOX4 arm (p ≤ 0.05).

CONCLUSIONS

TOMOX and FOLFOX4 seem to have similar efficacy and are well tolerated in the first-line treatment for advanced CRC with different profiles of toxicity. The convenient TOMOX regimen may offer an alternative to fluoropyrimidine-based regimens.

Variants in the Dihydropyrimidine Dehydrogenase, Methylenetetrahydrofolate Reductase and Thymidylate Synthase Genes Predict Early Toxicity of 5-Fluorouracil in Colorectal Cancer Patients

Adverse drug reactions to 5-fluorouracil (5-FU)-based chemotherapy have been reported to be due, in part, to genetic variants of the genes for the drug-related enzymes thymidylate synthase (TS; TYMS gene), methylenetetrahydrofolate reductase ( MTHFR gene) and dihydropyrimidine dehydrogenase (DPD; DPYD gene). This study investigated whether selected genetic variants of the TYMS, MTHFR and DPYD genes predict 5-FU-related early toxicity. The prevalence of the genetic variants was determined in 122 colorectal cancer patients and in a reference population of 320 blood donors. Subgroup analysis of 68 of the colorectal cancer patients was carried out to determine the relationship between selected gene variants detected in peripheral mononuclear cells and tolerability during the first or second cycle of 5-FU based treatment. Toxicity was linked to the TYMS 2R/2R variant (relative risk [RR] 1.66; sensitivity 0.37; specificity 0.77) and to the MTHFR c1298 C/C genetic variant (RR 1.77; sensitivity 0.17; specificity 0.91). Patients with the genetic variant IVS14+1 G/A or c1896 C/T in the DPYD gene had a statistically significant increased risk of experiencing toxicity (RR 2 and 6, respectively), both having a high specificity (0.97 and 0.98, respectively) and low sensitivity (0.04 and 0.13, respectively). It is concluded that pre-treatment detection of genetic variants can help to predict early toxicity experienced by patients receiving 5-FU-based chemotherapy.

[Severe toxicity following capecitabine administration because of dihydropyrimidine deshydrogenase (DPD) deficiency]

Capecitabine is an anticancer agent, prodrug of 5 fluorouracil (5-FU) administered orally and with a narrow therapeutic index. In gastrointestinal cancer, capecitabine is indicated for the treatment of colorectal cancer and metastatic unresectable gastric cancer. The 5-FU is active by incorporation in the biosynthesis of nucleic acids. Inhibition of endogenous synthesis of thymidine is the main way of toxicity of 5-FU. 5-FU is metabolised by the dihydopyrimydine dehydrogenase (DPD). Patients with a DPD deficiency can experience severe toxicity of 5-FU. We report the case of a patient who presented signs of major toxicity justifying hospitalization in intensive care unit 11 days after capecitabine initiation. Investigations showed that he had a DPD deficiency. This case leads to explain the different biological ways to identify patients at risk of developing severe toxicity following capecitabine administration because of DPD deficiency. Is it possible to make a systematic screening before initiation of treatment with 5-FU or prodrug of 5-FU?

Screening for Dihydropyrimidine Dehydrogenase Deficiency: To Do or Not To Do, That's The Question

The treatment of cancer patients with 5-fluorouracil (5FU)-based chemotherapy can be accompanied by severe and sometimes lethal toxicity. Dihydropyrimidine dehydrogenase (DPD) plays a pivotal role in the metabolism of 5FU and as such, a deficiency of DPD has been recognized as an important risk factor, predisposing patients to the development of severe 5FU-associated toxicity. To date, screening of patients for the presence of a DPD deficiency prior to the treatment is not yet routinely performed. Taking into account the relatively small impact of adjuvant 5FU-based chemotherapy on survival, patients should be informed about the risks of the therapy and should be offered the possibility of testing for the presence of a DPD deficiency in advance of receiving such treatment.

Effects of 5-fluorouracil adjuvant treatment of colon cancer

Since the late 1980s and early 1990s, 5-fluorouracil-based chemotherapy has been the standard adjuvant treatment for Stage III colon cancer. After the initial introduction of 5-fluorouracil in standard treatment protocols, several changes have been made based on results of randomized studies on various treatment regimens, including new cytotoxic agents. In Stage II patients, the role of adjuvant chemotherapy is debatable. However, there might be a role for adjuvant treatment in certain high-risk patients. Following a search of the Medline database, the results of randomized studies on 5-fluorouracil-based adjuvant therapy are reviewed, and future therapeutic options are discussed.

Dihydropyrimidine dehydrogenase and the efficacy and toxicity of 5-fluorouracil

The identification of genetic factors associated with either responsiveness or resistance to 5-fluorouracil (5-FU) chemotherapy, as well as genetic factors predisposing patients to the development of severe 5-FU-associated toxicity, is increasingly being recognised as an important field of study. Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of 5-fluorouracil (5-FU). Although the role of tumoral levels as a prognostic factor for clinical responsiviness has not been firmly established, there is ample evidence that a deficiency of DPD is associated with severe toxicity after the administration of 5-FU. Patients with a partial DPD deficiency have an increased risk of developing grade IV neutropenia. In addition, the onset of toxicity occurred twice as fast compared with patients with a normal DPD activity. To date, 39 different mutations and polymorphisms have been identified in DPYD. The IVS14+1G>A mutation proved to be the most common one and was detected in 24-28% of all patients suffering from severe 5-FU toxicity. Thus, a deficiency of DPD appears to be an important pharmacogenetic syndrome.

Irinotecan and raltitrexed: an active combination in advanced colorectal cancer

BACKGROUND

Irinotecan and raltitrexed are active agents in metastatic colorectal cancer. Preclinical findings suggest a remarkable synergistic activity between the two drugs and the feasibility of this association has been shown in a recent phase I study. The aim of our phase II trial was to assess the efficacy and tolerability of the combination of irinotecan and raltitrexed in patients with metastatic colorectal cancer untreated with chemotherapy.

PATIENTS AND METHODS

From June 1998 to February 2000, 46 patients were enrolled. Patients received irinotecan 350 mg/m(2) on day 1 and raltitrexed 2.6 mg/m(2) on day 2, every 3 weeks, for up to nine courses. Tumour assessment was performed every three cycles.

RESULTS

A total of 223 cycles of chemotherapy, with a median number of six (range 1-9) courses per patient, was administered. According to intention-to-treat analysis, the overall response rate was 46% (95% confidence interval 31% to 61%). The median duration of response was 21 weeks (range 11-> or =101), the median time to progression 27 weeks (range 1-> or =116), and the median overall survival 57 weeks (range 1-> or =130). The main toxicities were diarrhoea, with National Cancer Institute common toxicity criteria grade 3/4 in 26% of patients, grade 3/4 neutropenia in 20%, grade 3 nausea-vomiting in 13%, grade 3 asthenia in 11% and grade 3/4 transaminase elevation in 4%.

CONCLUSIONS

Results achieved with irinotecan and raltitrexed show that this regimen is active, despite 'not-negligible' toxicity, and may represent a useful regimen for specific subgroups of colorectal cancer patients.