2,4-Dihydroxypyridine

Neoadjuvant chemoradiation for locally advanced rectal cancer: a systematic review of the literature with network meta-analysis.[Pubmed:30697067]

Cancer Manag Res. 2019 Jan 15;11:741-758.

Background: Neoadjuvant chemoradiotherapy (CRT) prior to surgery is a standard therapy for locally advanced rectal cancer, but the optimum regime is not conclusive. This meta-analysis evaluated various CRT regimens with regard to the rate of pathologic complete response (pCR) and toxic effects of grade >/=3. Methods: The databases PubMed, Cochrane Library, and Embase were searched for randomized controlled trials (RCTs) that compared neoadjuvant CRT regimes for treating patients with locally advanced rectal cancer, published before 28 December 2017. The primary end points were pCR and toxic effects. A network meta-analysis was applied. Results: Fourteen RCTs (with 5,599 participants) involving the following eight regimens were included: fluorouracil (5FU) alone, or 5FU with oxaliplatin (OXA), cisplatin, or irinotecan (CPT-11); capecitabine (CAP) alone, or CAP with OXA or CPT-11; and CPT-11 with combined tegafur, 5-chloro-2,4-Dihydroxypyridine, and potassium oxonate. The rate of pCR associated with CAP + OXA was significantly higher compared with 5FU alone; there were no significant differences among the other regimens. The toxicity of 5FU + OXA or CAP + OXA was significantly worse than that of 5FU alone or CAP alone. CAP + OXA and CAP were ranked, respectively, the most and second most effective regimens in terms of pCR rate. 5FU alone and CAP alone likely had the lowest and second lowest toxicity, respectively. Conclusion: Among the currently available CRT regimens for locally advanced rectal cancer, this meta-analysis indicated that CAP + OXA provides the superior clinical results. Adding OXA to 5FU or CAP significantly increases toxicity.

5-Chloro-2,4-dihydroxypyridine, CDHP, prevents lung metastasis of basal-like breast cancer cells by reducing nascent adhesion formation.[Pubmed:29356434]

Cancer Med. 2018 Feb;7(2):463-470.

A drug for metastasis prevention is necessary. The orally administered anticancer drug S-1 contributes to cancer therapy. In a mouse xenograft model of metastatic breast cancer from our previous study, the administration of S-1 inhibited lung metastasis. However, the mechanism of inhibition remains elusive. S-1 contains 5-chloro-2,4-Dihydroxypyridine (CDHP), which does not have the antigrowth activity, but prevents the degradation of 5-fluorouracil, an anticancer reagent. In this study, we found that CDHP treatment shrinks cell morphology in metastatic basal-like breast cancer cell lines. Wound healing assays showed reduced cell migration in CDHP-treated cells. At the molecular level, CDHP treatment reduced the number of nascent adhesions, whereas the number of mature focal adhesions was not changed. These findings indicate that CDHP impairs focal adhesion formation, which results in a reduction in cell migration. For the in vivo metastasis assay, we used a highly lung-metastatic cell line. We xenografted them into immunodeficient mice, and administered CDHP. To determine whether CDHP prevents metastasis, we measured the weights of harvested lungs. The results showed that the lung weights of the CDHP-treated animals were not significantly different compared to the no-tumor controls, whereas the vehicle group showed a number of metastatic foci and an increase in lung weight. These observations indicate that CDHP administration prevents metastasis. This study reveals a novel effect of CDHP for lung metastasis prevention. Our findings may facilitate the establishment of future metastasis prevention therapies.

Gimeracil enhances the antitumor effect of cisplatin in oral squamous cell carcinoma cells in vitro and in vivo.[Pubmed:28927087]

Oncol Lett. 2017 Sep;14(3):3349-3356.

Gimeracil or 5-chloro-2,4-Dihydroxypyridine (CDHP) enhances the antitumor effects of 5-fluorouracil (5-FU) by inhibiting dihydropyrimidine dehydrogenase (DPD), which is involved in the degradation of 5-FU. CDHP, as part of a combination therapy, was also reported to exert a radiosensitizing effect. Therefore, CDHP may have underlying mechanisms of action other than DPD inhibition. The focus of the present study was to investigate the antitumor effects of CDHP and cisplatin (CDDP) combination treatment in vitro and in vivo against oral squamous cell carcinoma (OSCC) tumors. The inhibitory growth effects of CDHP and/or CDDP treatment on SAS and HSC2 cells were examined using an MTT assay. The expression levels of DNA double strand break repair proteins, including Ku70, DNA-dependent-protein kinase catalytic subunit (DNA-PKcs), Rad50 and Rad51 in CDHP and/or CDDP-treated cells were detected using western blotting. Nude mice with SAS or HSC2 tumors were treated with CDHP (administered orally 7 times/week) and/or CDDP (administered by intraperitoneal injection once/week) for 2 weeks. Combined treatment of CDHP and CDDP significantly suppressed the growth of SAS and HSC2 cells in vitro and that of tumors in vivo compared with the effects caused by single drug only or control treatments. Western blotting demonstrated that the expression levels of Ku70, DNA-PKcs, Rad50 and Rad51 were downregulated in cells treated with CDHP and CDDP combination treatment. Immunohistochemistry also identified that the expression of DNA double strand break repair proteins was downregulated in tumors treated with CDHP and CDDP combination treatment compared with that of tumors treated with CDDP alone or control. The results of the current study suggest that CDHP may be responsible for enhancing the antitumor effects of CDDP by suppressing the DNA double strand break repair system. Therefore, the combination of CDHP and CDDP may be a potential effective option for OSCC treatment.

Development of new promising antimetabolite, DFP-11207 with self-controlled toxicity in rodents.[Pubmed:28652707]

Drug Des Devel Ther. 2017 Jun 7;11:1693-1705.

To reduce 5-fluorouracil (5-FU)-induced serious toxicities without loss of antitumor activity, we have developed DFP-11207, a novel fluoropyrimidine, which consists of 1-ethoxymethyl-5-fluorouracil (EM-FU; a precursor form of 5-FU), 5-chloro-2,4-Dihydroxypyridine (CDHP; an inhibitor of 5-FU degradation), and citrazinic acid (CTA; an inhibitor of 5-FU phosphorylation). In vitro studies of DFP-11207 indicated that it strongly inhibited the degradation of 5-FU by dihydropyrimidine dehydrogenase (DPD) in homogenates of the rat liver, and also inhibited the phosphorylation of 5-FU by orotate phosphoribosyltransferase (OPRT) in tumor tissues in a similar magnitude of potency by CDHP and CTA, respectively. Especially, DFP-11207 inhibited the intracellular phosphorylation of 5-FU in tumor cells in a dose-dependent manner whereas CTA alone did not protect intracellular 5-FU phosphorylation. These results postulate that DFP-11207 rapidly entered into the cell and the free CTA produced from DFP-11207 inhibited the phosphorylation of 5-FU in the cell. Furthermore, following oral administration of DFP-11207, CTA was found to be highly retained in the gastrointestinal (GI) tract compared to other tissues in rats. Interestingly, EM-FU, the prodrug of 5-FU was found to specifically produce 5-FU by various species of liver microsomes. When DFP-11207 was administered to rats, the plasma level of 5-FU was persisted for a long-time with lower Cmax and longer half-life than that from other 5-FU prodrugs. The antitumor activity of DFP-11207 was evaluated in human tumor xenografts in nude rats and found that DFP-11207 showed an antitumor activity in a dose-dependent fashion and its efficacy is equivalent to reference 5-FU drugs. In striking contrast, DFP-11207 manifested no or less 5-FU-related toxicities, such as a decrease in body weights, GI injury, and myelosuppression, especially thrombocytopenia. Taken together, the preclinical evaluation of DFP-11207 strongly indicates that DFP-11207 be a potential new version of the oral fluoropyrimidine prodrug for further clinical development.

S-1-Induced Lacrimal Drainage Obstruction and Its Association with Ingredients/Metabolites of S-1 in Tears and Plasma: A Prospective Multi-institutional Study.[Pubmed:28253565]

Cancer Res Treat. 2018 Jan;50(1):30-39.

PURPOSE: This prospective study was conducted to determine the incidence of lacrimal drainage obstruction (LDO) during S-1 chemotherapy and evaluate the association between the development of LDO and the concentrations of ingredients/metabolites of S-1 in tears and plasma. MATERIALS AND METHODS: A total of 145 patients with gastric cancer who received adjuvant S-1 therapy were enrolled. Ophthalmologic examinations were performed regularly during S-1 chemotherapy. Concentrations of tegafur, 5-chloro-2,4-Dihydroxypyridine (CDHP), and 5-fluorouracil at steady-state trough level were measured in both tears and plasma. RESULTS: Fifty-three patients (37%) developed LDO. The median time to the onset of LDO was 10.9 weeks, and LDO developed most frequently in the nasolacrimal duct. Univariable analyses revealed that an older age (>/= 70 years), creatinine clearance rate (Ccr) < 80 mL/min, 5-fluorouracil concentration in plasma >/= 22.3 ng/mL (median), CDHP concentration in plasma >/= 42.0 ng/mL (median), and tegafur concentration in tears >/= 479.2 ng/mL (median) were related to increased development of LDO. Multivariable analysis indicated that a high plasma 5-fluorouracil concentration was predictive of increased development of LDO (hazard ratio, 2.02; p=0.040), along with older age and decreased Ccr. Patients with LDO also developed S-1-related non-hematologic toxicity more frequently than those without LDO (p=0.016). CONCLUSION: LDO is a frequent adverse event during S-1 chemotherapy. An older age, decreased Ccr, and high plasma 5-fluorouracil concentration were found to be independent risk factors for LDO. The high incidence of LDO warrants regular ophthalmologic examination and early intervention in patients receiving S-1 therapy.

Pharmacokinetics of initial full and subsequent reduced doses of S-1 in patients with locally advanced head and neck cancer-effect of renal insufficiency.[Pubmed:28159957]

Jpn J Clin Oncol. 2017 May 1;47(5):407-412.

Background: S-1 is a combination of tegafur [metabolized to 5-fluorouracil (5-FU)] with the modulators gimeracil (5-chloro-2,4-Dihydroxypyridine) and oteracil potassium. 5-Chloro-2,4-Dihydroxypyridine maintains plasma 5-FU concentrations by inhibiting dihydropyrimidine dehydrogenase, a pyrimidine catabolism enzyme that degrades 5-FU. As 50% of 5-chloro-2,4-Dihydroxypyridine is excreted in urine, renal insufficiency may increase its blood level, increasing 5-FU concentrations. We investigated whether special dose modification is needed in the presence of renal insufficiency. Objective: We compared steady state pharmacokinetics of 5-FU for the initial S-1 dose and reduced doses in patients with head and neck cancer requiring dose reduction due to renal and non-renal toxicities. Methods: Chemoradiotherapy with S-1 and cisplatin was administered every 5 weeks for two courses with a radiation dose totaling 70 Gy over 33-35 fractions. Two additional courses of adjuvant chemotherapy were administered in the case of an objective response. The S-1 and/or cisplatin dose was reduced in response to renal, hematologic or other toxicities. The primary endpoint was the change in area under the plasma concentration-versus-time curve from time 0-10 hours (5-FU AUCss 0-10) between the initial and reduced S-1 doses. Results: Although the mean 5-FU levels in patients with non-renal toxicities significantly decreased between the full and reduced dose, the full-dose and reduced-dose mean maximum 5-FU plasma concentrations at steady state (Css max) and AUCss 0-10 in patients with renal insufficiency were similar. Conclusions: Standard S-1 dose reduction for renal toxicity did not result in a significant decrease in 5-FU levels at steady state. A greater reduction to lower plasma 5-chloro-2,4-Dihydroxypyridine may be necessary in patients with renal insufficiency.

Meta-analysis Exploring the Effectiveness of S-1-Based Chemotherapy for Advanced Non-Small Cell Lung Cancer.[Pubmed:27980246]

Tohoku J Exp Med. 2017 Jan;241(1):1-11.

S-1 is a new oral fluoropyrimidine formulation that comprises tegafur, 5-chloro-2,4-Dihydroxypyridine, and potassium oxonate. S-1 is designed to enhance antitumor activity and to reduce gastrointestinal toxicity. Several studies have demonstrated that both S-1 monotherapy and S-1 combination regimens showed encouraging efficacies and mild toxicities in the treatment of lung squamous cell carcinoma and adenocarcinoma. However, it is unclear whether S-1 can be used as standard care in advanced non-small cell lung cancer (NSCLC). The purpose of this meta-analysis was to assess the efficacy and safety of S-1-based chemotherapy, compared with standard chemotherapy, in patients with locally advanced or metastatic NSCLC. Thirteen randomized controlled trials (RCTs) involving 2,134 patients with a similar ratio of different pathological types were included. In first-line or second-line chemotherapy, compared with standard chemotherapy, S-1-based chemotherapy showed similar efficacy in terms of median overall survival (mOS), median progression free survival (mPFS), and objective response rate (ORR) (all P > 0.1), and significantly reduced the incidence of grade >/= 3 hematological toxicities. In patients with locally advanced NSCLC receiving concurrent chemoradiotherapy, compared with standard chemoradiotherapy, significantly improved survival in the S-1-based chemotherapy was noted in terms of mOS and mPFS (risk radio [RR] = 1.289, P = 0.009; RR = 1.289, P = 0.000, respectively) with lower incidence of grade >/= 3 neutropenia (RR = 0.453, P = 0.000). The present meta-analysis demonstrates that S-1-based chemotherapy shows similar benefits in advanced NSCLC and improves survival in locally advanced NSCLC, compared with standard treatment.

Development of an S-1 dosage formula based on renal function by a prospective pharmacokinetic study.[Pubmed:26304171]

Gastric Cancer. 2016 Jul;19(3):876-86.

BACKGROUND: S-1 is an oral anticancer drug, containing tegafur (a prodrug of 5-fluorouracil, 5-FU), 5-chloro-2,4-Dihydroxypyridine, and potassium oxonate. As renal dysfunction is known to increase exposure of 5-FU following S-1 administration, the incidence of severe adverse reactions is increased in patients with impaired renal function. However, no reliable information on its dose modification for patients with renal dysfunction has been provided. METHODS: We conducted a prospective pharmacokinetic study to develop an S-1 dosage formula based on renal function. Sixteen cancer patients with various degrees of renal function received a single dose of S-1 at 40 mg/m(2). A series of blood samples were collected at predefined times within 24 h to assess the plasma concentration profiles of 5-FU, 5-chloro-2,4-Dihydroxypyridine, and tegafur. A mathematical model for the relationship between renal function and exposure of 5-FU was constructed by a population pharmacokinetic analysis. RESULTS: The clearance of 5-FU following S-1 administration was related to body surface area and creatinine clearance in the range 15.9-108.8 mL/min as estimated by the Cockcroft-Gault equation. The S-1 dosage formula was derived as follows:[Formula: see text]where AUC is the area under the concentration-time curve, CLcr is creatinine clearance, and BSA is body surface area. The recommended daily doses of S-1 in Asia and Europe were also proposed as nomograms according to exposure matching to the previously reported area under the concentration-time curve of 5-FU, which confirmed the efficacy and toxicity in pivotal registration studies. CONCLUSIONS: We have developed a novel formula for determining the S-1 dosage on the basis of renal function. Further validation is needed to confirm the formula for practical application.