Regorafenib synergizes with TAS102 against multiple gastrointestinal cancers and overcomes cancer stemness, trifluridine-induced angiogenesis, ERK1/2 and STAT3 signaling regardless of KRAS or BRAF mutational status.

Single-agent TAS102 (trifluridine/tipiracil) and regorafenib are FDA-approved treatments for metastatic colorectal cancer (mCRC). We previously reported that regorafenib combined with a fluoropyrimidine can delay disease progression in clinical case reports of multidrug-resistant mCRC patients. We hypothesized that the combination of TAS102 and regorafenib may be active in CRC and other gastrointestinal (GI) cancers and may in the future provide a treatment option for patients with advanced GI cancer. We investigated the therapeutic effect of TAS102 in combination with regorafenib in preclinical studies employing cell culture, colonosphere assays that enrich for cancer stem cells, and in vivo. TAS102 in combination with regorafenib has synergistic activity against multiple GI cancers in vitro including colorectal and gastric cancer, but not liver cancer cells. TAS102 inhibits colonosphere formation and this effect is potentiated by regorafenib. In vivo anti-tumor effects of TAS102 plus regorafenib appear to be due to anti-proliferative effects, necrosis and angiogenesis inhibition. Growth inhibition by TAS102 plus regorafenib occurs in xenografted tumors regardless of p53, KRAS or BRAF mutations, although more potent tumor suppression was observed with wild-type p53. Regorafenib significantly inhibits TAS102-induced angiogenesis and microvessel density in xenografted tumors, as well inhibits TAS102-induced ERK1/2 activation regardless of RAS or BRAF status in vivo. TAS102 plus regorafenib is a synergistic drug combination in preclinical models of GI cancer, with regorafenib suppressing TAS102-induced increase in microvessel density and p-ERK as contributing mechanisms. The TAS102 plus regorafenib drug combination may be further tested in gastric and other GI cancers.

Efficacy of Regorafenib and Trifluridine/Tipiracil According to Extended RAS Evaluation in Advanced Metastatic Colorectal Cancer Patients: A Multicenter Retrospective Analysis.

BACKGROUND: There are few molecular markers driving treatment selection in later lines of treatment for advanced colorectal cancer patients. The vast majority of patients who progress after first- and second-line therapy undergo chemotherapy regardless of molecular data. OBJECTIVE: We aimed to assess the prognostic and predictive effects of specific RAS mutations on overall survival of patients receiving regorafenib (rego), trifluridine/tipiracil (TFD/TPI), or both. PATIENTS AND METHODS: This was a retrospective observational study based on data from a previous study of our research network, involving nine Italian institutions over a 10-year timeframe (2012-2022). Extended RAS analysis, involving KRAS exon 2-4 and NRAS exon 2-4, and BRAF were the main criteria for inclusion in this retrospective evaluation. Patients with BRAF mutation were excluded. Patients were classified according to treatment (rego- or TFD/TPI-treated) and RAS mutational status (wild-type [WT], KRAS codon 12 mutations, KRAS codon 13 mutations, KRAS rare mutations and NRAS mutations, KRAS G12C mutation and KRAS G12D mutation). RESULTS: Overall, 582 patients were included in the present analysis. Overall survival did not significantly differ in rego-treated patients according to RAS extended analysis, although a trend toward a better median survival in patients carrying G12D mutation (12.0 months), Codon 13 mutation (8.0 months), and Codon 12 mutation (7.0 months) has been observed, when compared with WT patients (6.0 months). Overall survival did not significantly differ in TFD/TPI-treated patients according to RAS extended analysis, although a trend toward a better median survival in WT patients had been observed (9.0 months) in comparison with the entire population (7.0 months). Patients receiving both drugs displayed a longer survival when compared with the population of patients receiving rego alone (p = 0.005) as well as the population receiving TFD/TPI alone (p < 0.001), suggesting a group enriched for favorable prognostic factors. However, when each group was analyzed separately, the addition of TFD/TPI therapy to the rego-treated group improved survival only in all-RAS WT patients (p = 0.003). Differently, the addition of rego therapy to TFD/TPI-treated patients significantly improved OS in the Codon 12 group (p = 0.0004), G12D group (p = 0.003), and the rare mutations group (p = 0.02), in addition to all-RAS WT patients (p = 0.002). The rego-TFD/TPI sequence, compared with the reverse sequence, significantly improved OS only in the KRAS codon 12 group (p = 0.003). CONCLUSIONS: Our data demonstrate that RAS mutations do not affect outcome in rego-treated patients as well as TFD/TPI-treated patients. Nevertheless, a trend toward a higher efficacy of rego in RAS-mutated (in particular codon 12, rare RAS mutations, and G12D) patients has been recorded. The rego-TFD/TPI sequence seems to be superior to the reverse sequence in patients carrying an RAS codon 12 mutation, although the impact of other factors as disease burden or performance status cannot be excluded.

Combination of ganciclovir and trifluridine prevents drug-resistance emergence in HSV-1.

Ocular herpes simplex virus 1 (HSV-1) infections can lead to visual impairment. Long-term acyclovir (ACV) prophylaxis reduces the frequency of recurrences but is associated with drug resistance. Novel therapies are needed to treat drug-resistant HSV-1 infections. Here, we describe the effects of trifluridine (TFT) in combination with ACV or ganciclovir (GCV) on HSV-1 replication and drug-resistance emergence. Wild-type HSV-1 was grown under increasing doses of one antiviral (ACV, GCV, or TFT) or combinations thereof (ACV + TFT or GCV + TFT). Virus cultures were analyzed by Sanger sequencing and deep sequencing of the UL23 [thymidine kinase (TK)] and UL30 [DNA polymerase (DP)] genes. The phenotypes of novel mutations were determined by cytopathic effect reduction assays. TFT showed overall additive anti-HSV-1 activity with ACV and GCV. Five passages under ACV, GCV, or TFT drug pressure gave rise to resistance mutations, primarily in the TK. ACV + TFT and GCV + TFT combinatory pressure induced mutations in the TK and DP. The DP mutations were mainly located in terminal regions, outside segments that typically carry resistance mutations. TK mutations (R163H, A167T, and M231I) conferring resistance to all three nucleoside analogs (ACV, TFT, and GCV) emerged under ACV, TFT, ACV + TFT pressure and under GCV + TFT pressure initiated from suboptimal drug concentrations. However, higher doses of GCV and TFT prevented drug resistance in the resistance selection experiments. In summary, we identified novel mutations conferring resistance to nucleoside analogs, including TFT, and proposed that GCV + TFT combination therapy may be an effective strategy to prevent the development of drug resistance.

A Phase II Study of FOLFIRI Plus Ziv-Aflibercept After Trifluridine/Tipiracil Plus Bevacizumab in Patients with Metastatic Colorectal Cancer: WJOG 11018G.

BACKGROUND: Non-inferiority of trifluridine/tipiracil (FTD/TPI) plus bevacizumab (BEV) to irinotecan/fluoropyrimidine plus BEV in metastatic colorectal cancer was investigated in the phase III TRUSTY study, and we conducted a phase II study of FOLFIRI (5-FU+leucovorin+irinotecan) plus zib-aflibercept (AFL) after FTD/TPI plus BEV. However, the TRUSTY study failed during the recruitment of our patients. OBJECTIVE: We present the findings of a phase II study on the efficacy of FOLFIRI plus zib-aflibercept (AFL) after FTD/TPI plus BEV, including clinical results with plasma biomarker analyses. METHODS: This was a multicenter, single-arm, phase II study in patients with metastatic colorectal cancer refractory or intolerant to oxaliplatin, fluoropyrimidine, BEV, and FTD/TPI. The primary endpoint was progression-free survival. Fifteen plasma angiogenesis-associated biomarkers were analyzed using a Luminex® multiplex assay U-kit. RESULTS: Between January 2020 and May 2022, 26 patients (median age, 68 years) from 15 sites were enrolled. The median progression-free survival was 4.9 months (85% confidence interval, 3.4 month-not estimated). The overall response and disease control rates were 8% and 62%, respectively. The median levels of vascular endothelial growth factor-A and placental growth factor, both targets of AFL, were below the measurable limit of 30 pg/mL and 16 pg/mL, respectively. Patients were divided into two groups at the median levels of baseline biomarkers. The progression-free survival did not differ between high and low expressers of placental growth factor (p = 0.7), while it tended to be shorter in those with high levels of osteopontin (p = 0.05), angiopoietin-2 (p = 0.07), and tissue inhibitor of matrix metalloproteinases-1 (p = 0.1). CONCLUSIONS: This study did not meet the primary endpoint. Hence, FOLFIRI plus AFL should not be used after FTD/TPI plus BEV for metastatic colorectal cancer. Further studies are needed to determine factors not targeted by AFL that may affect the efficacy of the treatment. CLINICAL TRIAL REGISTRATION: jRCTs041190100.

Efficacy and Safety of Trifluridine/Tipiracil-Containing Combinations in Colorectal Cancer and Other Advanced Solid Tumors: A Systematic Review.

We performed a systematic literature review to identify and summarize data from studies reporting clinical efficacy and safety outcomes for trifluridine/tipiracil (FTD/TPI) combined with other antineoplastic agents in advanced cancers, including metastatic colorectal cancer (mCRC). We conducted a systematic search on May 29, 2021, for studies reporting one or more efficacy or safety outcome with FTD/TPI-containing combinations. Our search yielded 1378 publications, with 38 records meeting selection criteria: 35 studies of FTD/TPI-containing combinations in mCRC (31 studies second line or later) and 3 studies in other tumor types. FTD/TPI plus bevacizumab was extensively studied, including 19 studies in chemorefractory mCRC. Median overall survival ranged 8.6-14.4 months and median progression-free survival 3.7-6.8 months with FTD/TPI plus bevacizumab in refractory mCRC. Based on one randomized and several retrospective studies, FTD/TPI plus bevacizumab was associated with improved outcomes compared with FTD/TPI monotherapy. FTD/TPI combinations with chemotherapy or other targeted agents were reported in small early-phase studies; preliminary data indicated higher antitumor activity for certain combinations. Overall, no safety concerns existed with FTD/TPI combinations; most common grade ≥ 3 adverse event was neutropenia, ranging 5%-100% across all studies. In studies comparing FTD/TPI combinations with monotherapy, grade ≥ 3 neutropenia appeared more frequently with combinations (29%-67%) vs. monotherapy (5%-41%). Discontinuation rates due to adverse events ranged 0%-11% for FTD/TPI plus bevacizumab and 0%-17% with other combinations. This systematic review supports feasibility and safety of FTD/TPI plus bevacizumab in refractory mCRC. Data on non-bevacizumab FTD/TPI combinations remain preliminary and need further validation.

Trifluridine for treatment of mpox infection in drug combinations in ophthalmic cell models.

The Mpox virus can cause severe disease in the susceptible population with dermatologic and systemic manifestations. Furthermore, ophthalmic manifestations of mpox infection are well documented. Topical trifluridine (TFT) eye drops have been used for therapy of ophthalmic mpox infection in patients, however, its efficacy against mpox virus infection in this scenario has not been previously shown. In the present study, we have established ophthalmic cell models suitable for the infection with mpox virus. We show, that TFT is effective against a broad range of mpox isolates in conjunctival epithelial cells and keratocytes. Further, TFT remained effective against a tecovirimat-resistant virus strain. In the context of drug combinations, a nearly additive effect was observed for TFT combinations with brincidofovir and tecovirimat in conjunctival epithelial cells, while a slight antagonism was observed for both combinations in keratocytes. Altogether, our findings demonstrate TFT as a promising drug for treatment of ophthalmic mpox infection able to overcome tecovirimat resistance. However, conflicting results regarding the effect of drug combinations with approved compounds warrant close monitoring of such use in patients.

Exploratory Biomarker Analysis Using Plasma Angiogenesis-Related Factors and Cell-Free DNA in the TRUSTY Study: A Randomized, Phase II/III Study of Trifluridine/Tipiracil Plus Bevacizumab as Second-Line Treatment for Metastatic Colorectal Cancer.

BACKGROUND: The TRUSTY study evaluated the efficacy of second-line trifluridine/tipiracil (FTD/TPI) plus bevacizumab in metastatic colorectal cancer (mCRC). OBJECTIVE: This exploratory biomarker analysis of TRUSTY investigated the relationship between baseline plasma concentrations of angiogenesis-related factors and cell-free DNA (cfDNA), and the efficacy of FTD/TPI plus bevacizumab in patients with mCRC. PATIENTS AND METHODS: The disease control rate (DCR) and progression-free survival (PFS) were compared between baseline plasma samples of patients with high and low plasma concentrations (based on the median value) of angiogenesis-related factors. Correlations between cfDNA concentrations and PFS were assessed. RESULTS: Baseline characteristics (n = 65) were as follows: male/female, 35/30; median age, 64 (range 25-84) years; and RAS status wild-type/mutant, 29/36. Patients in the hepatocyte growth factor (HGF)-low and interleukin (IL)-8-low groups had a significantly higher DCR (risk ratio [95% confidence intervals {CIs}]) than patients in the HGF-high (1.83 [1.12-2.98]) and IL-8-high (1.70 [1.02-2.82]) groups. PFS (hazard ratio {HR} [95% CI]) was significantly longer in patients in the HGF-low (0.33 [0.14-0.79]), IL-8-low (0.31 [0.14-0.70]), IL-6-low (0.19 [0.07-0.50]), osteopontin-low (0.39 [0.17-0.88]), thrombospondin-2-low (0.42 [0.18-0.98]), and tissue inhibitor of metalloproteinase-1-low (0.26 [0.10-0.67]) groups versus those having corresponding high plasma concentrations of these angiogenesis-related factors. No correlation was observed between cfDNA concentration and PFS. CONCLUSION: Low baseline plasma concentrations of HGF and IL-8 may predict better DCR and PFS in patients with mCRC receiving FTD/TPI plus bevacizumab, however further studies are warranted. CLINICAL TRIAL REGISTRATION NUMBER: jRCTs031180122.

Bevacizumab mitigates codon-specific effects of trifluridine/tipiracil on efficacy outcome parameters in metastatic colorectal cancer.

BACKGROUND: Molecular informed therapy changed treatment patterns of metastatic colorectal cancer (mCRC). Recently KRAS G12, the most prevalent RAS mutation in mCRC, was investigated to be a negative predictive marker for the efficacy of trifluridine/tipiracil (FTD/TPI). Whether this proposed selectivity remains when FTD/TPI is combined with bevacizumab remains elusive. We aimed to describe the efficacy of FTD/TPI + bevacizumab depending on the RAS mutational status in a real-world population. PATIENTS AND METHODS: Patients from five different cancer centers in Austria who received FTD/TPI + bevacizumab in any treatment line having available information on their molecular profile were eligible. Data were retrospectively collected by chart review. Survival data were compared using log-rank test. Multivariate Cox regression models included several established covariates. RESULTS: One hundred and twenty-three patients with mCRC were included in this study. Median overall survival (OS) was highly similar in the RAS wild type (WT) [9.63 months (95% confidence interval [CI] 8.055-13.775 months)] and the RAS mutant cohorts [8.78 months (95% CI 8.055-11.014 months)], which was confirmed in a multivariable model adjusting for potential confounders; hazard ratio (HR): 1.05 (95% CI 0.618-1.785; P = 0.857). In addition, no effect of KRAS G12 status on patient outcome was observed. In detail, OS was 8.88 months (95% CI 7.332-12.921 months) in patients with KRAS G12 mutation, compared to 9.47 months (95% CI 8.088-11.375 months) in patients with RAS WT/no-KRAS G12 disease [HR: 0.822 (95% CI 0.527-1.282; P = 0.387)]. CONCLUSION: This real-world study indicates that the efficacy of FTD/TPI + bevacizumab is independent of RAS mutational status and that bevacizumab may therefore mitigate the potentially limited efficacy of FTD/TPI monotherapy in the KRAS G12-mutated population.

Combination therapy with WEE1 inhibition and trifluridine/tipiracil against esophageal squamous cell carcinoma.

Despite advanced therapeutics, esophageal squamous cell carcinoma (ESCC) remains one of the deadliest cancers. Here, we propose a novel therapeutic strategy based on synthetic lethality combining trifluridine/tipiracil and MK1775 (WEE1 inhibitor) as a treatment for ESCC. This study demonstrates that trifluridine induces single-strand DNA damage in ESCC cells, as evidenced by phosphorylated replication protein 32. The DNA damage response includes cyclin-dependent kinase 1 (CDK1) (Tyr15) phosphorylation as CDK1 inhibition and a decrease of the proportion of phospho-histone H3 (p-hH3)-positive cells, indicating cell cycle arrest at the G2 phase before mitosis entry. The WEE1 inhibitor remarkedly suppressed CDK1 phosphorylation (Try15) and reactivated CDK1, and also increased the proportion of p-hH3-positive cells, which indicates an increase of the number of cells into mitosis. Trifluridine combined with a WEE1 inhibitor increased trifluridine-mediated DNA damage, namely DNA double-strand breaks, as shown by increased γ-H2AX expression. Moreover, the combination treatment with trifluridine/tipiracil and a WEE1 inhibitor significantly suppressed tumor growth of ESCC-derived xenograft models. Hence, our novel combination treatment with trifluridine/tipiracil and a WEE1 inhibitor is considered a candidate treatment strategy for ESCC.

A Systematic Review and Meta-Analysis of Trifluridine/Tipiracil plus Bevacizumab for the Treatment of Metastatic Colorectal Cancer: Evidence from Real-World Series.

BACKGROUND: Colorectal cancer is the most prevalent gastrointestinal neoplasm. When metastatic, the disease has limited systemic treatment options. Novel targeted therapies have expanded these options for subsets with specific molecular alterations, such as microsatellite instability (MSI)-high cancers, but additional treatments and combinations are in urgent need to improve outcomes and improve survival of this incurable disease. The fluoropyrimidine-derivative trifluridine, in combination with tipiracil, has been introduced as a third-line treatment, and more recently, it was studied in combination with bevacizumab. This meta-analysis reports on studies with this combination in clinical practice outside clinical trials. METHODS: A literature search in the Medline/PubMed and Embase databases was executed for finding series of trifluridine/tipiracil with bevacizumab in metastatic colorectal cancer. Criteria for inclusion in the meta-analysis were English or French language of the report, inclusion of twenty or more patients with metastatic colorectal cancer treated with trifluridine/tipiracil in combination with bevacizumab outside of a trial and containing information regarding response rates, progression-free survival (PFS), and overall survival (OS). Information on the demographics of the patients and on adverse effects of treatment was also collected. RESULTS: Eight series with a total of 437 patients were eligible for the meta-analysis. The performed meta-analysis discovered a summary response rate (RR) of 2.71% (95% confidence interval (CI): 1.11-4.32%) and a disease control rate (DCR) of 59.63% (95% CI: 52.06-67.21%). Summary PFS was 4.56 months (95% CI: 3.57-5.55 months), and summary OS was 11.17 months (95% CI: 10.15-12.19 months). Common adverse effects identified mirrored the adverse-effect profile of the two components of the combination. CONCLUSION: The current systematic review and meta-analysis reports the efficacy of trifluridine/tipiracil with bevacizumab in advanced lines of therapy for metastatic colorectal cancer in the setting of clinical practice outside clinical trials. Discovery of predictive biomarkers of response to trifluridine/tipiracil with bevacizumab will promote the tailoring of this treatment to individual patients to maximize clinical benefit.

Treatment Settings and Outcomes with Regorafenib and Trifluridine/Tipiracil at Third-Line Treatment and beyond in Metastatic Colorectal Cancer: A Real-World Multicenter Retrospective Study.

BACKGROUND: Patients with refractory mCRC rarely undergo third-line or subsequent treatment. This strategy could negatively impact their survival. In this setting, regorafenib (R) and trifluridine/tipiracil (T) are two key new treatment options with statistically significant improvements in overall survival (OS), progression-free survival (PFS), and disease control with different tolerance profiles. This study aimed to retrospectively evaluate the efficacy and safety profiles of these agents in real-world practice. MATERIALS AND METHODS: In 2012-2022, 866 patients diagnosed with mCRC who received sequential R and T (T/R, n = 146; R/T, n = 116]) or T (n = 325]) or R (n = 279) only were retrospectively recruited from 13 Italian cancer institutes. RESULTS: The median OS is significantly longer in the R/T group (15.9 months) than in the T/R group (13.9 months) (p = 0.0194). The R/T sequence had a statistically significant advantage in the mPFS, which was 8.8 months with T/R vs. 11.2 months with R/T (p = 0.0005). We did not find significant differences in outcomes between groups receiving T or R only. A total of 582 grade 3/4 toxicities were recorded. The frequency of grade 3/4 hand-foot skin reactions was higher in the R/T sequence compared to the reverse sequence (37.3% vs. 7.4%) (p = 0.01), while grade 3/4 neutropenia was slightly lower in the R/T group than in the T/R group (66.2% vs. 78.2%) (p = 0.13). Toxicities in the non-sequential groups were similar and in line with previous studies. CONCLUSIONS: The R/T sequence resulted in a significantly longer OS and PFS and improved disease control compared with the reverse sequence. R and T given not sequentially have similar impacts on survival. More data are needed to define the best sequence and to explore the efficacy of sequential (T/R or R/T) treatment combined with molecular-targeted drugs.

Phase II Trial of Trifluridine/Tipiracil Plus Irinotecan in Patients with Advanced, Refractory Biliary Tract Carcinoma.

BACKGROUND: We sought to determine the safety and efficacy of trifluridine/tipiracil in combination with irinotecan in a phase II trial setting for refractory, advanced unresectable biliary tract carcinoma (BTC). METHODS: A total of 28 patients (27 were evaluable) with advanced BTCs who progressed on at least one prior systemic therapy were enrolled and were treated with trifluridine/tipiracil 25 mg/m2 (days 1-5 of 14-day cycle) and irinotecan 180 mg/m2 (day 1 of the 14-day cycle). The primary endpoint for the study was 16-week progression-free survival (PFS16) rate. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and safety were pre-specified secondary endpoints. RESULTS: Of 27 patients, PFS16 rate was 37% (10/27; 95% CI: 19%-58%), thereby meeting the criteria for success for the primary endpoint. The median PFS and OS of the entire cohort were 3.9 months (95% CI: 2.5-7.4) and 9.1 months (95% CI: 8.0-14.3), respectively. In the patients evaluable for tumor response (n = 20), the ORR and DCR were 10% and 50%, respectively. Twenty patients (74.1%) had at least one grade 3 or worse adverse event (AE), and 4 patients (14.8%) had grade 4 AEs. A total of 37% (n = 10/27) and 51.9% (n = 14/27) experienced dose reductions in trifluridine/tipiracil and irinotecan, respectively. Delay in therapy was noted in 56% of the patients while 1 patient discontinued the therapy, primarily due to hematologic AEs. CONCLUSION: The combination of trifluridine/tipiracil plus irinotecan is a potential treatment option for patients with advanced, refractory BTCs with good functional status and no targetable mutations. A larger randomized trial is needed to confirm these results. (ClinicalTrials.gov Identifier: NCT04072445).

Effects and mechanisms of trifluridine alone or in combination with cryptotanshinone in inhibiting malignant biological behavior of gastric cancer.

BACKGROUND: The incidence of gastric cancer (GC) ranks fourth among all malignant tumors worldwide, and the fatality rate ranks second among all malignant tumors. Several Chinese traditional medicines have been used in the treatment of advanced gastric cancer. This study aims to investigate the effect of combinational use of natural product cryptotanshinone (CTS) with anti-cancer drug trifluorothymidine (FTD) in GC. METHODS: Cell Counting Kit-8 assay was used to detect the inhibitory effect of the combinational or separate use of FTD and CTS on the growth of HGC-27 and AGS GC cells. The combined index of FTD and CTS was calculated using CompuSyn software. To understand the mechanism, we applied flow cytometry to study the cell cycle and cell apoptosis after treatment. We also investigated the amount of FTD incorporated into the DNA by immunofluorescence assay. The expression of relevant proteins was monitored using western blot. Furthermore, the effect of using TAS-102 in combination with CTS was studied in xenograft tumor nude mice model. RESULTS: FTD and CTS inhibited the growth of GC cells in a dose-dependent manner, respectively. They both exhibited low to sub-micromolar potency in HGC-27 and AGS cells. The combination of FTD and CTS showed synergistic anticancer effect in HGC-27 cells and AGS cells. Our mechanism studies indicate that FTD could block HGC-27 cells at G2/M phase, while CTS could block HGC-27 cells at G1/G0 phase, while FTD combined with CTS could mainly block HGC-27 cells at G2 phase. FTD in combination with CTS significantly increased the apoptosis of HGC-27 cells. We observed that CTS treatment increased the incorporation of FTD into the DNA HGC-27 cell. FTD treatment activated STAT3 phosphorylation in HGC-27 cells, while CTS treatment down-regulated the concentration of p-STAT3. Interestingly, the combination of CTS and FTD reduced STAT3 phosphorylation induced by FTD. In the in vivo experiments, we observed that the combination of TAS-102 with CTS was significantly more potent than TAS-102 on tumor growth inhibition. CONCLUSIONS: FTD combined with CTS has a synergistic anti-gastric cancer effect as shown by in vitro and in vivo experiments, and the combined treatment of FTD and CTS will be a promising treatment option for advanced gastric cancer.

A Phase II Trial of Trifluridine/Tipiracil in Combination with Cetuximab Rechallenge in Patients with RAS Wild-Type mCRC Refractory to Prior Anti-EGFR Antibodies: WJOG8916G Trial.

BACKGROUND: Trifluridine/tipiracil (FTD/TPI) improved the overall survival in patients with metastatic colorectal cancer (mCRC) who had previously received standard chemotherapies; however, the clinical outcomes remain poor. OBJECTIVE: A multicenter phase II study aimed to assess the efficacy and safety of FTD/TPI plus cetuximab rechallenge. PATIENTS AND METHODS: Patients with histologically confirmed RAS wild-type mCRC refractory to prior anti-epidermal growth factor receptor (anti-EGFR) antibody were enrolled and treated with FTD/TPI (35 mg/m2 twice daily on days 1-5 and 8-12) plus cetuximab (initially 400 mg/m2, followed by weekly 250 mg/m2) every 4 weeks. The primary endpoint was disease control rate (DCR), expecting a target DCR of 65% and null hypothesis of 45% with 90% power and 10% one-sided alpha error. Gene alterations of RAS, BRAF, EGFR, PIK3CA, ERBB2, and MET in pre-treatment circulating tumor DNA were evaluated using the Guardant360 assay. RESULTS: A total of 56 patients (median age 60 years; left-sided tumors 91%; objective partial or complete response during the prior anti-EGFR therapy 61%) were enrolled. The DCR was 54% (80% confidence interval [CI] 44-63; P = 0.12), with a partial response rate of 3.6%. Median progression-free survival (PFS) was 2.4 months (95% CI 2.1-3.7). In the circulating tumor DNA analysis, patients without any alterations of the six genes (n = 20) demonstrated higher DCR (75% vs. 39%; P = 0.02) and longer PFS (median 4.7 vs. 2.1 months; P < 0.01) than those with any gene alterations (n = 33). The most common grade 3/4 hematologic adverse event was neutropenia (55%). No treatment-related deaths occurred. CONCLUSIONS: FTD/TPI plus cetuximab rechallenge did not demonstrate clinically meaningful efficacy in all mCRC patients, but might be beneficial for the molecularly selected population.

AZD6738 promotes the tumor suppressive effects of trifluridine in colorectal cancer cells.

Ataxia telangiectasia and Rad3­related (ATR) is a kinase that repairs DNA damage. Although inhibitors that selectively target ATR have been developed, their effectiveness in colorectal cancer has not been widely reported. The present study hypothesized that anticancer agents that effectively act in the S phase before the G2/M checkpoint may be ideal agents for concomitant use with ATR inhibitors, which act at the G2/M checkpoint. Therefore, the present study examined the combined effects of AZD6738, an ATR inhibitor, and trifluridine (FTD), which acts in the S phase and has a high DNA uptake rate. In vitro cell viability assays, flow cytometry and western blotting were performed to evaluate cell viability, and changes in cell cycle localization and protein expression. The results revealed that in colorectal cancer cells, the combination of AZD6738 and FTD inhibited cell viability, cell cycle arrest at the G2/M checkpoint and Chk1 phosphorylation, and increased apoptotic protein expression levels more than that when treated with FTD alone. HT29, a BRAF­mutant cell line known to be resistant to anticancer drugs, was used to induce tumors in vivo. Since FTD does not have sufficient efficacy when administered orally, it was mixed with tipiracil to prevent degradation; this mixture is known as TAS­102. TAS­102 alone exerted minimal tumor suppressive effects; however, when used in combination with AZD6738, tumor suppression was observed, suggesting that AZD6738 may increase the effectiveness of a weakly effective drug. Although ATR inhibitors are effective against p53 mutants, the present study demonstrated that these inhibitors were also effective against the p53 wild­type HCT116 colorectal cancer cell line. In conclusion, combination therapy with AZD6738 and FTD enhanced the inhibition of tumor proliferation in vitro and in vivo. In the future, we aim to investigate the potentiating effect of AZD6738 on 5­fluouracil­resistant cell lines that are difficult to treat.

Evaluation of a Novel Combination Therapy, Based on Trifluridine/Tipiracil and Fruquintinib, against Colorectal Cancer.

INTRODUCTION: Trifluridine/tipiracil hydrochloride (FTD/TPI, Lonsurf®) is an oral antineoplastic agent that has been approved as late-stage chemotherapy for colorectal cancer. Its major mechanism of action is the dysfunction of tumoral DNA including DNA strand breaks and decreased replication. Fruquintinib (ELUNATE®) is a novel kinase inhibitor that selectively inhibits the vascular endothelial growth factor receptor-1, -2, and -3. In this study, we evaluated the antitumor activity of combination therapy with FTD/TPI and fruquintinib in vivo. METHODS: The enhancement of the antitumor effects with FTD/TPI and fruquintinib combination, compared to the single drugs given alone was evaluated using two human colorectal cancer xenografts in nude mouse models. FTD/TPI (200 mg/kg) was orally administered for 5 consecutive days followed by 2 days of rest in a 7-day period. Fruquintinib (10 mg/kg) was orally administered consecutively for 2 and 3 weeks in SW48 and HCT 116 tumor-bearing models, respectively. After treatment with these agents, the microvessel density was evaluated by CD31 immunohistochemical analyses. RESULTS: In both models, FTD/TPI and fruquintinib significantly inhibited tumor growth, and the activity of the combined treatment was significantly superior to that of either monotherapy. Body weight loss of greater than 20% was not observed in any group. A histochemical analysis showed nuclei enlargement, abnormal mitosis, and karyorrhexis in the FTD/TPI treatment group. The microvessel density in the HCT 116 tumors treated with FTD/TPI and fruquintinib was significantly lower than that in the control group. CONCLUSION: The combination of FTD/TPI and fruquintinib could be a promising treatment option for colorectal cancer.

Real-World Activity and Safety of Trifluridine-Tipiracil Plus Bevacizumab Therapy in Patients with Refractory Metastatic Colorectal Cancer.

BACKGROUND: The combination of trifluridine-tipiracil and bevacizumab was compared with trifluridine-tipiracil monotherapy in a randomized, open-label, phase II trial, resulting in a statistically significant and clinically relevant improvement in progression-free survival (PFS), with tolerable toxicity in patients with refractory metastatic colorectal cancer (mCRC); however, evidence supporting the role of this combination in a real-world setting is limited. OBJECTIVE: The aim of our work was to provide further evidence on the activity and safety of this combination in a real-world series of Western mCRC patients refractory or intolerant to previous therapies. PATIENT AND METHODS: We conducted a retrospective, observational study of patients with mCRC refractory or intolerant to standard therapies. Patients were treated with trifluridine-tipiracil and bevacizumab. Previous therapy with fluoropyrimidines, irinotecan, oxaliplatin, bevacizumab, aflibercept, regorafenib, and cetuximab or panitumumab (only RAS wild-type) was allowed, as was previous participation in clinical trials. Clinicopathological characteristics, overall response rate (ORR), disease control rate (DCR), overall survival (OS), PFS, and safety data were retrospectively collected and analyzed. RESULTS: We recorded 31 patients treated between 1 December 2017 and 30 June 2022. Median age was 69 years (range 38-82 years), 39% were male, 100% had an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-1, tumor location was left-sided in 77% of cases, 54% had synchronous presentation, 35% were RAS mutant, 3% were BRAF mutant, and 71% underwent primary tumor resection; 64% of patients had liver metastases, 55% had lung metastases, and 23% had peritoneal carcinomatosis. The median number of previous treatment lines was 2 (range 0-5), and 84% of patients received at least one previous anti-angiogenic agent. The ORR and DCR were 3% and 71%, respectively. With a median follow-up of 8 months (range 2-39), median PFS was 6 months (95% confidence interval [CI] 3.1-8.9 months) and median OS was 14 months (95% CI 10.1-17.8 months). Adverse events of any grade were reported in 58% of patients. The most common grade 3-4 toxicities were neutropenia (19%) and anemia (6%); 35% of patients required either dose delays or dose reductions due to toxicity. Granulocyte colony-stimulating factor (G-CSF) prophylaxis was administered either on first or subsequent cycles of treatment in 35% of patients. No treatment-related deaths occurred. Sixty percent of the patients who discontinued treatment eventually received one or more lines of subsequent therapy. CONCLUSIONS: Our series provides further evidence on the activity and safety of the combination of trifluridine-tipiracil and bevacizumab in a real-world series of Western refractory mCRC patients.

Single-cell transcriptional pharmacodynamics of trifluridine in a tumor-immune model.

Understanding the immunological effects of chemotherapy is of great importance, especially now that we have entered an era where ever-increasing pre-clinical and clinical efforts are put into combining chemotherapy and immunotherapy to combat cancer. Single-cell RNA sequencing (scRNA-seq) has proved to be a powerful technique with a broad range of applications, studies evaluating drug effects in co-cultures of tumor and immune cells are however scarce. We treated a co-culture comprised of human colorectal cancer (CRC) cells and peripheral blood mononuclear cells (PBMCs) with the nucleoside analogue trifluridine (FTD) and used scRNA-seq to analyze posttreatment gene expression profiles in thousands of individual cancer and immune cells concurrently. ScRNA-seq recapitulated major mechanisms of action previously described for FTD and provided new insight into possible treatment-induced effects on T-cell mediated antitumor responses.

Effect of KRAS codon 12 or 13 mutations on survival with trifluridine/tipiracil in pretreated metastatic colorectal cancer: a meta-analysis.

BACKGROUND: KRAS gene mutations can predict prognosis and treatment response in patients with metastatic colorectal cancer (mCRC). METHODS: We undertook a meta-analysis of three randomized, placebo-controlled trials (RECOURSE, TERRA and J003) to investigate the impact of KRAS mutations in codons 12 or 13 on overall survival (OS) and progression-free survival in patients receiving trifluridine/tipiracil (FTD/TPI) for refractory mCRC. RESULTS: A total of 1375 patients were included, of whom 478 had a KRAS codon 12 mutation and 130 had a KRAS codon 13 mutation. In univariate analyses, the absence of a KRAS codon 12 mutation was found to significantly increase the OS benefit of FTD/TPI relative to placebo compared with the presence of the mutation {hazard ratio (HR), 0.62 [95% confidence interval (CI): 0.53-0.72] versus 0.86 (0.70-1.05), respectively; interaction P = 0.0206}. Multivariate analyses showed that taking confounding factors into account reduced the difference in treatment effect between the presence and the absence of KRAS codon 12 mutations, confirming that treatment benefit was maintained in patients with [HR, 0.73 (95% CI: 0.59-0.89)] and without [HR, 0.63 (95% CI: 0.54-0.74)] codon 12 mutations (interaction P = 0.2939). KRAS mutations in codon 13 did not reduce the OS benefit of FTD/TPI relative to placebo, and, furthermore, KRAS mutations at either codon 12 or codon 13 did not affect the progression-free survival benefit. CONCLUSIONS: Treatment with FTD/TPI produced a survival benefit, relative to placebo, regardless of KRAS codon 12 or 13 mutation status in patients with previously treated mCRC.