Detection of trifluridine in tumors of patients with metastatic colorectal cancer treated with trifluridine/tipiracil

Lineage of drug discovery research on fluorinated pyrimidines: chronicle of the achievements accomplished by Professor Setsuro Fujii

Prof. Setsuro Fujii achieved significant results in the field of drug discovery research in Japan. He developed nine well-known drugs: FT, UFT, S-1 and FTD/TPI are anticancer drugs, while cetraxate hydrochloride, camostat mesilate, nafamostat mesilate, gabexate mesilate and pravastatin sodium are therapeutic drugs for various other diseases. He delivered hope to patients with various diseases across the world to improve their condition. Even now, drug discovery research based on Dr. Fujii's ideas is continuing.

Outcomes of Patients with Metastatic Colorectal Cancer Treated with Trifluridine/Tipiracil beyond the Second Line: A Multicenter Retrospective Study from Saudi Arabia

Background

The outcome of patients with refractory metastatic colorectal cancer (mCRC) treated with trifluridine/tipiracil (FTD/TPI) beyond the second-line has not been studied in Saudi Arabia. Therefore, this multicenter retrospective analysis was conducted to evaluate the efficacy of FTD/TPI.

Methods

This multicenter retrospective analysis included five centers in Saudi Arabia. FTD/TPI was administered to all the patients beyond the oxaliplatin- and irinotecan-based chemotherapy regimens. The electronic medical records were reviewed, and progression-free survival (PFS) and overall survival (OS) were determined.

Results

The study included 100 patients with a mean age of 55.4 ± 11.8 years. The overall response to FTD/TPI was 4%. The median PFS was 4 months (95% confidence interval (CI) 3.487–4.513), and the median OS was 11 months (95% CI, 9.226–12.771). In a Cox regression analysis of the independent predictors for PFS, advanced stage of the disease (P = 0.037; HR, 2.614; and CI, 1.102–7.524), presence of lymph node metastasis (P = 0.018; HR, 3.664; and 95% CI, 1.187–8.650), and >2 metastatic sites (P = 0.020; HR, 1.723; and 95% CI, 1.089–2.727) were independent factors predicting disease progression. The Cox regression analysis confirmed that age ≥ 55 years (P = 0.046; HR, 1.667; and 95%, 1.097–3.100), advanced disease stage (P = 0.044; HR, 1.283; and 95% CI, 1.035–2.940), prior use of adjuvant chemotherapy (P = 0.037; HR, 0.892; and 95% CI, 0.481–0.994), liver metastasis (P = 0.025; HR, 2.015; and 95% CI, 1.091–3.720), >2 metastatic sites (P = 0.038; HR, 1.248; and 95% CI, 1.036–1.846), development of neutropenia after receiving first cycle of FTD/TPI (P = 0.042; HR, 1.505; and 95% CI, 1.064–2.167), and increased number of FTD/TPI cycles (P = 0.002; HR, 0.769; and 95% CI, 0.664–0.891) were independent variables for OS.

Conclusion

Treatment with FTD/TPI is feasible and effective in daily clinical practice in Saudi Arabian patients. The risk of progression increased with advanced disease stage, lymph node metastasis, bone metastasis, and metastasis to >2 sites. Age ≥ 55 years, advanced disease stage, liver metastasis, metastasis to >2 sites, neutropenia after the first cycle of FTD/TPI, and increased number of FTD/TPI cycles were independent factors predicting mortality.

Biomarkers of Trifluridine-Tipiracil Efficacy

Trifluridine/tipiracil (TAS-102) is a newer generation chemotherapy that has been approved for the later-line treatment of metastatic colorectal and gastric/gastroesophageal adenocarcinomas. The oral drug provides a modest benefit of prolongation of survival over placebo in pretreated patients with these cancers with acceptable toxicity. Studies have shown rare objective responses (2-4%), and the disease control rates were 44% in both colorectal and gastric cancer randomized trials. Thus, the majority of patients progress through treatment and are burdened by toxicities. To better characterize the sub-group of patients with a higher probability of benefit from trifluridine/tipiracil, predictive biomarkers have been sought using data from randomized trials as well as from non-randomized trials and real-world series. Biomarkers examined include clinical characteristics of the patients, laboratory tests, and tumor derived biomarkers. These studies show that early neutropenia on treatment, and ratios of leukocyte subsets, are potential biomarkers able to predict trifluridine/tipiracil benefit. Combinations of laboratory values and clinical characteristics and proteins involved in trifluridine transport and activation have been examined with initial positive results.

Monitoring FTD in the peripheral blood mononuclear cells of elderly patients with metastatic colorectal cancer administered FTD plus bevacizumab as first-line treatment

Trifluridine/tipiracil (FTD/TPI) is an orally administrated anticancer drug with efficacy validated for patients with metastatic colorectal cancer (mCRC) or gastric cancer. FTD, a key component of FTD/TPI, exerts antitumor effects via its incorporation into DNA. Using specific antibodies against bromodeoxyuridine, FTD incorporation into DNA is detected in tumors and peripheral blood mononuclear cells (PBMC) of patients with mCRC who are administered FTD/TPI. The proportion of FTD‐positive PBMC fluctuates according to the schedule of treatment, although the association between the proportion of FTD‐positive PBMC and the clinical outcomes of patients is unknown. To answer this question, here we monitored the FTD‐positive PBMC of 39 elderly patients with mCRC enrolled in KSCC1602, a single‐arm phase 2 trial of FTD/TPI plus bevacizumab as a first‐line treatment, for 1 month, during the first cycle of treatment. The median values and interquartile ranges of the percentage of FTD‐positive PBMC on days 8, 15, and 29 were 39.3% (30.7%‐52.2%), 66.9% (40.0%‐75.3%), and 13.5% (5.7%‐26.0%), respectively. Receiver operating characteristic analysis revealed that the percentage of FTD‐positive PBMC on day 8 (the end of the first week of treatment) had moderate ability to accurately diagnose the occurrence of severe neutropenia and leukopenia within 1 month (area under the curve = 0.778 [95% confidence interval, 0.554‐0.993]). This result suggests that excess FTD incorporation into PBMC at the initial phase of FTD/TPI plus bevacizumab treatment is a risk factor for early onset of severe hematological adverse events.

Efficacy of Combination Chemotherapy Using a Novel Oral Chemotherapeutic Agent, FTD/TPI, with Ramucirumab Murine Version DC101 in a Mouse Syngeneic Cancer Transplantation Model

Trifluridine/tipiracil (FTD/TPI) (a.k.a. TAS-102) is a combination drug for metastatic colorectal cancer (CRC) and severely pretreated metastatic gastric/gastroesophageal junction (GEJ) cancers, comprising FTD, a thymidine-based antineoplastic nucleoside analog, and TPI, which enhances FTD bioavailability. Herein, in KRAS mutant murine colorectal cancer CT26 syngeneic models, we investigate whether combination therapy with DC101 (a surrogate ramucirumab antibody, rat antimouse vascular endothelial growth factor receptor (VEGFR)-2 monoclonal antibody (mAb)) improves FTD/TPI efficacy. Tumor growth inhibition (TGI) on day 15 was 38.0% and 30.6% upon DC101 monotherapy and FTD/TPI monotherapy respectively, and 60.3% upon combination therapy. Tumor volume was significantly lower (p < 0.001) upon combination treatment than upon FTD/TPI or DC101 monotherapy, indicating the additive effects of FTD/TPI and DC101. DNA-incorporated FTD levels on Day 8 were significantly higher in combination therapy with FTD/TPI (for 5 consecutive days) and DC101 (on alternate days for 7days) than in FTD/TPI monotherapy. Furthermore, vascular endothelial cell-specific marker CD31 was downregulated in DC101-treated tumors on day 8. These results indicate that combination therapy with FTD/TPI and DC101 is a promising treatment alternative regardless of KRAS mutations.