Combination of enuracil and capecitabine for treatment of cancer

Abstract

The present invention relates to a method for treating cancer in a human subject. The method comprises: (a) orally administering enuracil to the subject at a dose of 30-60 mg / day; (b) orally administering capecitabine to the subject for consecutive 2-14 days at a dose of about 140-700 mg / day or a dose that provides a 5-FU exposure (AUC) of about 1500 h * ng / mL or greater at least 10 hours after step (a); and (c) repeating the steps (a) and (b) 3-14 days after the step (b). The pharmaceutical composition is suitable for treating colorectal cancer, gastrointestinal tumor, breast cancer, pancreatic cancer, head and neck cancer, lung cancer or advanced biliary tract cancer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 386,271, filed December 6, 2022, and U.S. Provisional Patent Application No. 63 / 513,525, filed July 13, 2023, both of which are hereby incorporated by reference in their entirety. Technical Field

[0003] The present invention relates to a method for treating cancer by orally administering eniluracil and capecitabine to cancer patients. The method provides an optimal dosing regimen and amount of eniluracil and capecitabine to improve the efficacy-safety profile of capecitabine. Background Art

[0004] 5-Fluorouracil (5-FU) is one of the most widely used chemotherapeutic drugs in the treatment of various tumors. 5-FU must be activated by metabolic conversion to deceptive uridine and deoxyuridine nucleotides that interfere with DNA synthesis and RNA function. Because 5-FU differs from its natural counterpart, uracil, only by the fluorine substitution at the 5-position, it is readily activated in cancer patients. Unfortunately, its structural similarity to uracil is also responsible for its rapid and extensive conversion to decomposition products that have no antitumor activity. The first step in the breakdown of 5-FU is by the drug-metabolizing enzyme dihydropyrimidine dehydrogenase (DPD: EC1312, uracil reductase).

[0005] DPD is a ubiquitous enzyme that is the first and rate-limiting step in the degradation (inactivation) of 5-FU. DPD is abundantly expressed in the gastrointestinal tract and liver, but is also present in other cells and cancer cells in the body. The oral bioavailability of 5-FU is poor due to extensive and rapid first-pass metabolism due to the high levels of DPD in the liver.

[0006] 5-Ethynyluracil, also known as eniluracil, is a DPD inhibitor, an irreversible inactivator of DPD, thereby reducing or eliminating the metabolic inactivation of 5-FU. Due to the structural similarity between eniluracil and 5-FU, eniluracil is a substrate for DPD. Co-administration of eniluracil with 5-FU can restore the oral bioavailability of 5-FU. Eniluracil has been shown to be safe when administered at doses up to 50 g / day for seven days. [1]

[0007] Capecitabine, the first oral fluoropyrimidine, was introduced as a promising alternative therapy that does not require infusion but still provides the benefits of 5-FU therapy. Capecitabine is a prodrug that is converted to 5-FU via three enzymatic steps. Thymidylate phosphorylase (TP) plays a key role in the conversion of capecitabine to its active metabolite and may be present at higher concentrations in some malignant tissues [2]. Clinical trials have shown an improved side effect profile when capecitabine therapy is compared with 5FU / LV therapy, including a reduction in stomatitis, diarrhea, nausea, and neutropenic sepsis. FDA Approval of Capecitabine It is used to treat Dukes' stage C colon cancer, metastatic colorectal cancer, and metastatic breast cancer. However, the use of approved doses of capecitabine showed a significant increase in the rates of hyperbilirubinemia and hand-foot syndrome [3]. Capecitabine was given at 1255 mg / m 2 Following oral administration, the PK parameters for capecitabine, 5-FU, 5-DFCR, and 5'-DFUR indicate rapid elimination (see Table 1 below). The observed exposure (AUC) for 5-FU was approximately 1630 h*ng / mL. The pharmacokinetic profile of FBAL was slightly prolonged, with a half-life of 3.23 hours and an AUC of 30-35,000 h*ng / mL [4].

[0008] Table 1.

[0009]

[0010] Reported C max , AUC 0-t and AUC 0-∞ The geometric mean (CV) of the t max The median value (minimum - maximum).

[0011] Reported 1 / 2 The arithmetic mean (CV) of

[0012] Descriptive statistics of pharmacokinetic parameters estimated on day 14 after administration of capecitabine (1255 mg / m2) in 8 cancer patients [4]. Summary of the Invention

[0013] In one aspect, the present disclosure provides a method for treating cancer in a human subject, comprising: (a) orally administering to the subject eniluracil at a dose of 30-60 mg / day; (b) orally administering to the subject a fixed dose of about 140-700 mg / day of capecitabine or a dose of capecitabine that provides a 5-FU exposure (AUC) of about 1500 h*ng / mL or greater for 2-14 consecutive days at least 10 hours after step (a); and (c) repeating steps (a) and (b) 3-14 days after step (b).

[0014] In another embodiment and in accordance with the above, eniluracil is administered at a dose of about 40 mg / day.

[0015] In another embodiment and in accordance with any of the above, capecitabine is administered at a dose of about 160-500 mg / day.

[0016] In another embodiment and in accordance with any of the above, step (b) occurs at least 17 hours after step (a). In some other further embodiments, step (b) occurs 10-24 hours after step (a).

[0017] In a further embodiment and in accordance with any of the above, step (c) occurs 7 days after step (b).

[0018] In further embodiments and in accordance with any of the above, the cancer is colorectal cancer, gastrointestinal tumor, breast cancer, pancreatic cancer, head and neck cancer, lung cancer, or advanced biliary tract cancer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The novel features of the invention are set forth in the appended claims. A better understanding of the features and advantages of the invention will be obtained by reference to the following detailed description which sets forth illustrative embodiments in which the principles of the invention are utilized and the accompanying drawings (also referred to herein as "Fig.", "FIG.", "Figure," "Figures," "Figs." and "FIGs."):

[0020] Figure 1 The antitumor efficacy of capecitabine and eniluracil in monotherapy and combination therapy is depicted. The median relative tumor volume over time for Groups 1-6 of the in vivo efficacy experiment is shown.

[0021] Figure 2 Depicted are the mean AUC of 5-FU observed on day 2 after treatment with eniluracil and capecitabine. 0-∞The solid line indicates the corresponding PK parameter data from the FDA regulatory submission for Xeloda. The dotted line indicates the corresponding PK parameter data from the EMA regulatory submission for Xeloda.

[0022] Figure 3 Depicts the C of 5-FU observed on day 2 after treatment with eniluracil and capecitabine. max Data. The solid line indicates the corresponding PK parameter data from Xeloda's FDA regulatory submission. The dotted line indicates the corresponding PK parameter data from Xeloda's EMA regulatory submission.

[0023] Figure 4 Depicted are the mean AUC of 5-FU observed on day 8 after treatment with eniluracil and capecitabine. 0-∞ The solid line indicates the corresponding PK parameter data from the FDA regulatory submission for Xeloda. The dotted line indicates the corresponding PK parameter data from the EMA regulatory submission for Xeloda.

[0024] Figure 5 Depicts the C of 5-FU observed on day 8 after treatment with eniluracil and capecitabine. max Data. The solid line indicates the corresponding PK parameter data from Xeloda's FDA regulatory submission. The dotted line indicates the corresponding PK parameter data from Xeloda's EMA regulatory submission.

[0025] Figure 6 Depicted are the mean AUC of FBAL observed on day 2 after treatment with eniluracil and capecitabine. 0-∞ The solid line indicates the corresponding PK parameter data from the FDA regulatory submission for Xeloda. The dotted line indicates the corresponding PK parameter data from the EMA regulatory submission for Xeloda.

[0026] Figure 7 Depicts the C of FBAL observed on day 2 after treatment with eniluracil and capecitabine. max Data. The solid line indicates the corresponding PK parameter data from Xeloda's FDA regulatory submission. The dotted line indicates the corresponding PK parameter data from Xeloda's EMA regulatory submission.

[0027] Figure 8 Depicted are the mean AUC of FBAL observed on day 8 after treatment with eniluracil and capecitabine. 0-∞ The solid line indicates the corresponding PK parameter data from the FDA regulatory submission for Xeloda. The dotted line indicates the corresponding PK parameter data from the EMA regulatory submission for Xeloda.

[0028] Figure 9Depicts the C of FBAL observed on day 8 after treatment with eniluracil and capecitabine. max Data. The solid line indicates the corresponding PK parameter data from Xeloda's FDA regulatory submission. The dotted line indicates the corresponding PK parameter data from Xeloda's EMA regulatory submission.

[0029] Figure 10 Depicted are the mean AUC of capecitabine observed on day 2 after treatment with eniluracil and capecitabine. 0-∞ Solid lines indicate corresponding PK parameter data from Xeloda FDA regulatory submission.

[0030] Figure 11 Depicted is the C of capecitabine observed on day 2 after treatment with eniluracil and capecitabine. max Data. Solid lines indicate corresponding PK parameter data from Xeloda FDA regulatory submission.

[0031] Figure 12 Depicted are the mean AUCs of DFCR observed on day 2 after treatment with eniluracil and capecitabine. 0-∞ Solid lines indicate corresponding PK parameter data from Xeloda FDA regulatory submission.

[0032] Figure 13 Depicts the C of DFCR observed on day 2 after treatment with eniluracil and capecitabine. max Data. Solid lines indicate corresponding PK parameter data from Xeloda FDA regulatory submission.

[0033] Figure 14 Depicted are the mean AUCs of DFUR observed on day 2 after treatment with eniluracil and capecitabine. 0-∞ Solid lines indicate corresponding PK parameter data from Xeloda FDA regulatory submission.

[0034] Figure 15 Depicts the C of DFUR observed on day 2 after treatment with eniluracil and capecitabine max Data. Solid lines indicate corresponding PK parameter data from Xeloda FDA regulatory submission.

[0035] Brief description of the form

[0036] Table 1 depicts the descriptive statistics of the pharmacokinetic parameters estimated on day 14 after administration of capecitabine (1255 mg / m2) in 8 cancer patients.

[0037] Table 2 depicts the design of the in vivo efficacy experiment of CXF 280 in athymic nude mice implanted subcutaneously with patient-derived colon cancer xenografts.

[0038] Table 3 depicts the antitumor efficacy of capecitabine (alone or in combination with eniluracil) expressed as a percentage of the minimum T / C value. The minimum T / C value recorded for a test group represents the maximum antitumor efficacy of the respective treatment.

[0039] Table 4 depicts the mean T of 5-FU on day 2 after treatment with capecitabine (alone or in combination with eniluracil) in different cohorts. max and T 1 / 2 data.

[0040] Table 5 depicts the mean C of 5-FU on day 2 after treatment with capecitabine (alone or in combination with eniluracil) in different cohorts. max data.

[0041] Table 6 depicts the mean AUC of 5-FU on day 2 after treatment with capecitabine (alone or in combination with eniluracil) in different cohorts. 最后 data.

[0042] Table 7 depicts an overview of the patient cohorts (1, 2A, 3, and 4), including: sex, age, cancer type, PCS6422 dose, capecitabine dose, and number of cycles completed.

[0043] Table 8 depicts a summary of ADRs reported in ≥5% of patients with colon cancer who received Xeloda monotherapy or intravenous 5-FU / LV in the adjuvant setting.

[0044] Table 9 depicts a summary of adverse events (Grade 2 or higher) observed in Cohorts 1, 2A, 3, and 4.

[0045] Table 10 depicts data regarding the RECIST analysis of lesions observed in patients enrolled in the clinical trial. DETAILED DESCRIPTION

[0046] The present inventors compared the anti-tumor efficacy of a combination of eniluracil and capecitabine using a 7 / 7 (capecitabine administration for 7 days and 7 days of rest) dosing regimen with capecitabine alone using a conventional 14 / 7 (capecitabine administration for 14 days and 7 days of rest) regimen in a preclinical xenograft model. The present inventors found that pretreatment with eniluracil before treatment with capecitabine allowed complete elimination of eniluracil in mice and enhanced the anti-tumor activity of capecitabine without significant impact on its safety and tolerability profile. In mice, pretreatment with 10 mg / kg of oral eniluracil before administration of 30 mg / kg or 15 mg / kg of oral capecitabine produced an efficacy comparable to that of 300 mg / kg of oral capecitabine alone. Notably, the total cumulative dose of capecitabine in the combination group was 1 / 13.3 and 1 / 26.6, respectively, compared to the capecitabine alone group.

[0047] Based on the inventors' xenograft model efficacy results, combined with previous knowledge of preclinical and clinical anti-tumor efficacy using eniluracil and 5-FU combination therapy, the inventors discovered the optimal dosing schedule and amount of eniluracil and capecitabine for treating cancer in patients who prefer fluoropyrimidine therapy alone.

[0048] The present application provides a method for treating cancer in a patient, wherein the cancer is of a type in which 5-FU or a 5-FU prodrug such as capecitabine is active. The method comprises the following steps: (a) first orally administering eniluracil to the patient at a dose of about 30-60 mg / day, (b) at least 10 hours after step (a), orally administering capecitabine to the patient at a dose of about 140-700 mg / day for 6-14 consecutive days, or orally administering capecitabine at a dose that provides a 5-FU exposure (AUC) of about 1500 h*ng / mL or greater; and (c) repeating steps (a) and (b) 7-14 days after step (b).

[0049] In step (a) of the method, at least about 30 mg / day or at least about 40 mg / day of eniluracil is administered to the patient. For example, about 40 mg / day, or about 50 mg / day, or about 60 mg / day of eniluracil is administered to the patient. Prior to administering the 5-FU prodrug capecitabine, the patient is first administered (i.e., pre-administered before capecitabine) eniluracil to substantially eliminate DPD activity in the patient's neural and non-neural tissues. "Substantially eliminate" means that the level of DPD activity in the patient's neural and non-neural tissues is reduced to less than 10% of the patient's baseline DPD activity before administration of eniluracil, and preferably is reduced to less than 5%, or less than 1%.

[0050] In step (b) of the method, capecitabine is administered between 10 and 24 hours after the administration of eniluracil. For example, capecitabine is administered at least 10 hours, 12 hours, 16 hours, 17 hours, and no more than 24 hours after the administration of eniluracil. The dosing regimen and the amount of capecitabine are selected to allow eniluracil to be substantially cleared from the patient's body before the administration of capecitabine, so that capecitabine is present in a molar excess (e.g., at least 5 times, at least 10 times, at least 25 times, at least 50 times, or at least 100 times) relative to the level of eniluracil remaining in the patient's body when capecitabine is administered. Thus, the potential interference of eniluracil with the metabolic activation of capecitabine is minimized, and thus the anti-tumor efficacy of capecitabine is not interfered with by eniluracil.

[0051] The patient is administered capecitabine at a dose of about 140 to 700 mg / day. For example, capecitabine is administered at a dose of 140-700 mg / day, 160-700 mg / day, 140 to 500 mg / day, 150-500 mg / day, 200-500 mg / day, 140-450 mg / day, 150-450 mg / day, 160-450 mg / day, 140-400 mg / day, 150-400 mg / day, or 300-400 mg / day.

[0052] Capecitabine may also be administered at a dose that provides a 5-FU exposure (AUC) of about 1500 h*ng / mL or greater.

[0053] Lower doses of capecitabine were ineffective or only partially effective. Higher doses of capecitabine would be expected to cause toxicity.

[0054] Capecitabine can be administered to the patient once a day, or more than once a day. Preferably, capecitabine is administered twice a day. Capecitabine is administered to the patient for 2-14 consecutive days, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 consecutive days.

[0055] In step (c) of the method, the patient receives the next cycle of eniluracil and capecitabine following steps (a) and (b) after the patient has rested for at least 3 to 14 days, for example, or after 3, 4, 5, 6 or 7 days, or after any number of days from 7 to 14 days.

[0056] Based on the physician's assessment of response and side effects, steps (a)-(c) are repeated. A physician can often stop treatment if the patient has a complete response or if the disease progresses in the patient. A complete response means the tumor is no longer present. Progression of the disease means the tumor begins to grow larger or is no longer stable. A stable tumor means the tumor has neither progressed nor regressed.

[0057] The present invention can be used to treat all cancers for which capecitabine is used, including but not limited to colorectal cancer, gastrointestinal tumors, breast cancer, pancreatic cancer, head and neck cancer, lung cancer, and advanced biliary (bile) cancer.

[0058] The present invention can be used to treat mammalian subjects, such as humans, horses, and dogs. The present invention is particularly useful in treating humans.

[0059] The method of the present invention provides effective treatment and is safe using an optimal dosing regimen and optimal amounts of eniluracil and capecitabine. The total cumulative dose of capecitabine administered in the method of the present invention is lower than the effective dose of capecitabine when used alone without eniluracil. This is beneficial because high-dose capecitabine treatment can cause side effects, leading to the need for dose reduction or interruption of treatment and the development of resistance to treatment, as evidenced by shorter progression-free survival and lower response rates in patients [5]. The method of the present invention can also be used to treat patients whose tumors are resistant to 5-FU or capecitabine therapy.

[0060] Example

[0061] The present invention is further illustrated by the following examples. These examples are intended only to illustrate the present invention and should not be construed as limiting.

[0062] Example 1. Antitumor efficacy of eniluracil and capecitabine in mice

[0063] A. Purpose

[0064] This study aimed to evaluate the antitumor efficacy of eniluracil combined with different doses of capecitabine in patient-derived colon xenografts, CXF 280, transplanted subcutaneously in immunodeficient athymic nude mice.

[0065] B. Mouse model

[0066] Human tumor explants transplanted directly from patients into nude mice and passaged subcutaneously, called patient-derived tumor xenografts (PDXs), retain most characteristics of the parental patient tumor, including histology and sensitivity to anticancer drugs. Studies have shown that PDXs passaged in nude mice accurately replicate the donor patient's response to standard cytotoxic anticancer drugs in >90% of cases. [6],[7],[8]

[0067] C. Study Design

[0068] The study consisted of in vivo efficacy experiments of CXF 280 in athymic nude mice implanted subcutaneously with patient-derived colon cancer xenografts.

[0069] The experiment consisted of six groups of six animals each. Animals were administered capecitabine monotherapy at 300 mg / kg / day or 30 mg / kg / day for 2 weeks, followed by a 1-week break, followed by daily dosing for 2 weeks (14 days of dosing and 7 days of rest). In the combination therapy, capecitabine was administered at 30, 15, or 7.5 mg / kg / day on days 1-7, 15-21, and 29-35 (7 days of dosing and 7 days of rest), and was administered together with 10 mg / kg / day of eniluracil on days 1, 3, 5, 15, 17, 19, 29, 31, and 33.

[0070] Combination therapy of capecitabine and eniluracil scheduled for administration on the same day was delayed 6 hours after the eniluracil administration to ensure that all eniluracil was eliminated from the mice before capecitabine administration.

[0071] All therapies were administered via oral gavage (po) over the course of 35 days, followed by a one-week observation period until day 42 of the experiment.

[0072] Table 2 shows the design of the experiment.

[0073] Table 2.

[0074]

[0075]

[0076] Control vehicle 1 Capecitabine: Water for injection; Control vehicle 2 and eniluracil: PBS pH 8.5

[0077] D. result

[0078] Figure 1 The antitumor efficacy of capecitabine and eniluracil in monotherapy and combination therapy is shown. The median relative tumor volume over time for Groups 1-6 is shown. The relative tumor volume (RTV) on day x is calculated by dividing the absolute individual tumor volume (Tx) on day x by the absolute individual tumor volume (Tr) of the same tumor on the day of randomization and multiplying by 100%.

[0079] Tumor growth inhibition was determined by comparing the median RTV of the test group (T) and the vehicle control group (C) and expressed as the minimum T / C value in percentage. The minimum T / C value recorded by the test group during the experiment represents the maximum antitumor efficacy of the respective treatment.

[0080] The antitumor efficacy is also shown in Table 3 by calculating the minimum T / C value (%) on day 35.

[0081] Table 3.

[0082]

[0083]

[0084] The above results show that monotherapy with 300 mg / kg / day of capecitabine in mice achieved high anti-tumor activity and was significantly more effective than monotherapy with 30 mg / kg / day. The combination therapy of capecitabine and eniluracil was most effective when using 30 or 15 mg / kg / day of capecitabine. Due to the addition of eniluracil and higher capecitabine exposure levels, a very high level of tumor growth inhibition was achieved at a much lower cumulative dose compared to the 7.5 mg / kg / day group. All combination therapies of capecitabine (30, 15 and 7.5 mg / kg / day) and eniluracil were more effective than monotherapy with capecitabine (30 mg / kg / day) because the cumulative dose was much lower due to the modified dosing regimen.

[0085] Example 2. Clinical research plan

[0086] A. Purpose:

[0087] To evaluate the safety, dose-limiting toxicities (DLTs), and maximum tolerated dose (MTD) of capecitabine administered to patients with advanced, refractory gastrointestinal (GI) tumors using a 7-day on-dose, 7-day off capecitabine regimen approximately 24 hours after a single, fixed, oral 40 mg dose of eniluracil.

[0088] B. Study Design:

[0089] This study was an open-label, multicenter study of patients with advanced, relapsed or refractory GI cancer or non-relapsed / refractory GI cancer who were intolerant to other therapies and who were judged by the investigator to be candidates for fluoropyrimidine monotherapy.

[0090] C. Inclusion criteria:

[0091] Patients who meet the following criteria will be eligible to participate in this study:

[0092] 1. Patients with advanced, metastatic, or unresectable gastrointestinal (GI) tract tumors that are refractory or intolerant to currently available therapies, for whom the investigators recommend fluoropyrimidine monotherapy.

[0093] 2. Have measurable disease according to the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines (version 1.1).

[0094] 3. Age ≥ 18 years old.

[0095] 4. Have not received intravenous (IV) 5FU or oral 5FU analogues treatment within 4 weeks before enrollment.

[0096] 5. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 at the beginning of the study.

[0097] 6. Adequate bone marrow, liver, and kidney function as assessed by the following laboratory requirements within 7 days prior to starting study treatment:

[0098] a. Peripheral ANC ≥ 1.5 × 109 / L;

[0099] b. Platelet count ≥75×109 / L in the absence of growth factors / blood transfusion;

[0100] c. Hemoglobin ≥8.5 g / dL in the absence of growth factors / blood transfusion;

[0101] d. Estimated glomerular filtration rate > 50 mL / min;

[0102] e. Total bilirubin <2× upper limit of normal (ULN); <5× ULN if the patient has liver metastasis or biliary tract cancer; or ≤3× ULN if the patient has Gilbert's disease;

[0103] f. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) <2.5×ULN, liver metastases <5×ULN; and

[0104] g. International normalized ratio (INR) <1.5.

[0105] 7. Life expectancy is at least 12 weeks.

[0106] 8. Female patients of reproductive potential and male patients with reproductive partners must agree to use effective contraception as described below from the time of screening until 60 days after the last dose of capecitabine:

[0107] highly effective methods of birth control, including hormonal contraceptives (for example, combined oral contraceptives, patches, vaginal rings, injections, and implants), intrauterine devices or intrauterine systems, vasectomy, or tubal ligation; or

[0108] an effective double-barrier method of contraception (two of the following: male condom, female condom, cervical cap, diaphragm, or contraceptive sponge); or

[0109] Abstain from sexual activity during the study and for 60 days after the last dose of capecitabine.

[0110] 9. Females of childbearing potential must have a negative serum β-human chorionic gonadotropin pregnancy test result within 3 days prior to the first dose of study treatment. Female patients sterilized by hysterectomy and / or bilateral oophorectomy or postmenopausal female patients (amenorrhea ≥ 12 months and at least 55 years of age) may be exempted from the β-human chorionic gonadotropin pregnancy test.

[0111] 10. Willing to provide written informed consent.

[0112] 11. Acute toxicity of previous therapy has resolved or stabilized to < Grade 2—except for Grade 2 neuropathy.

[0113] 12. If the patient is infected with human immunodeficiency virus (HIV), antiretroviral treatment must be used to control the viral load to an undetectable level.

[0114] 13. If the patient has hepatitis C infection and has received antiviral treatment, the viral load must be negative at the time of screening.

[0115] 14. If the patient has chronic hepatitis B and is receiving antiviral treatment, the viral load must be negative at the time of screening.

[0116] 15. Willing and able to comply with all protocol visits and assessments.

[0117] D. Exclusion criteria

[0118] Patients who meet any of the following criteria are not allowed to enroll in this study:

[0119] 1. Unable to take oral medications or suffering from a malabsorption syndrome that may interfere with drug absorption (e.g., short bowel syndrome or chronic, partial intestinal obstruction).

[0120] 2. The investigator considers that there is a history or presence of clinically significant 12-lead ECG abnormalities.

[0121] 3. Currently have brain metastasis.

[0122] 4. QTc prolongation (Fridericia correction) >480 milliseconds in both males and females at screening.

[0123] 5. Patients with a history of QTc prolongation, ventricular tachycardia / ventricular fibrillation, severe ventricular arrhythmia, or torsade de pointes, or a history of ventricular ablation for arrhythmia.

[0124] 6. Patients with congenital long QT syndrome or family history of long QT syndrome.

[0125] 7. Patients with other clinically significant heart disease, including but not limited to uncontrolled angina, myocardial ischemia or infarction within 6 months, congestive heart failure > Class II according to the New York Heart Association, or a history of myocarditis.

[0126] 8. Electrolyte disturbances, such as uncorrected hypokalemia / hyperkalemia, hypomagnesemia, or hypocalcemia. Patients can be enrolled after successful correction of electrolyte disturbances.

[0127] 9. Currently using any medication that cannot be discontinued and is included in the list of prohibited medications in the protocol (including those that can prolong QTc).

[0128] 10. Known hypersensitivity to any component of the study treatment.

[0129] 11. Other primary cancers requiring treatment within the past 3 years, excluding cervical intraepithelial neoplasia, ductal carcinoma in situ, or completely resected squamous or basal cell carcinoma.

[0130] 12. Pregnant or lactating women.

[0131] 13. Underwent major surgery, open biopsy or major trauma within 4 weeks before the first dose of study treatment.

[0132] 14. Patients are currently receiving or have received any study treatment within 4 weeks prior to entering the study, or are currently participating in another clinical study.

[0133] 15. Known DPD deficiency.

[0134] E. Medication administration and duration:

[0135] Eniluracil (40-50 mg) is administered orally on day 1. 12-24 hours later, capecitabine is administered orally. Capecitabine is administered twice daily at 140-600 mg / day for 7 days. The patient then rests for 7 days before receiving the next cycle following the above schedule. The cycle is repeated until the patient has a complete response or when the disease progresses in the patient. A complete response means that the tumor is no longer present. Progression of cancer means that the tumor begins to grow larger or the tumor is no longer stable.

[0136] F. The objectives of the trial are to:

[0137] 1. Main Purpose:

[0138] To evaluate the safety, dose-limiting toxicities (DLTs), and maximum tolerated dose (MTD) of capecitabine administered to patients with advanced, refractory gastrointestinal (GI) cancers using a 7-day on-dose, 7-day off capecitabine regimen approximately 24 hours after a single, fixed, oral 40 mg dose of eniluracil.

[0139] To characterize the pharmacokinetic (PK) profiles of capecitabine, 5-fluorouracil (5FU), and its major metabolites quantifiable in plasma: α-fluoro-β-alanine (FBAL), 5'-deoxy-5-fluorocytidine (5'DFCR), and doxifluridine (5'DFUR).

[0140] 2. Secondary objectives:

[0141] PK characteristics of uracil and its major metabolite 5-acetyluracil.

[0142] • To evaluate dihydropyrimidine dehydrogenase (DPD) enzyme activity over time following a single dose of eniluracil using the dihydrouracil to uracil ratio as a surrogate for enzyme activity or a yet-to-be-developed assay for DPD activity.

[0143] To evaluate the effect of eniluracil on heart rate-corrected QT (QTc).

[0144] The assessment focused specifically on the incidence of adverse events (AEs) (AESI), including the incidence of hand-foot syndrome (HFS).

[0145] 3. Exploratory purpose:

[0146] Obtain preliminary evidence of antitumor activity of eniluracil and capecitabine in advanced GI cancers.

[0147] G. The endpoints of the trial are:

[0148] 1. Primary End Point :

[0149] Incidence of DLTs and AEs according to NCI CTCAE version 5.0.

[0150] • Plasma concentrations and PK parameters of capecitabine, 5FU, FBAL, 5′DFCR, and 5′DFUR will be estimated using non-compartmental methods based on concentration-time data, as data permit.

[0151] Eniluracil concentrations in plasma; PK parameters will be estimated from concentration-time data using non-compartmental methods, where data permit.

[0152] 2. Secondary endpoints:

[0153] To assess the incidence of AESI, including HFS.

[0154] • Evaluate dihydropyrimidine dehydrogenase (DPD) enzyme activity using the dihydrouracil to uracil ratio as a surrogate for enzyme activity or a yet-to-be-developed DPD activity assay.

[0155] The QTc effect of eniluracil treatment will be assessed by comparing baseline ECGs before the first dose of eniluracil on Day 1, 2 hours ± 30 minutes after the first dose of eniluracil (maximum observed concentration [Cmax] level), and just before the administration of capecitabine on Day 2.

[0156] 3. Exploratory endpoints:

[0157] Investigators performed disease assessments according to standard of care every 8 weeks based on RECIST criteria (version 1.1).

[0158] 4. Pharmacokinetic endpoints:

[0159] The following PK parameters will be determined for eniluracil, 5-acetyluracil, capecitabine, 5FU, and the major metabolites FBAL, 5′-DFCR, and 5′-DFUR, as data permit:

[0160] Cmax: maximum observed plasma concentration;

[0161] tmax: time to peak plasma concentration;

[0162] AUC0-∞: the area under the plasma concentration-time curve from time zero to infinity;

[0163] AUC0-t: the area under the plasma concentration-time curve from time zero to the last sample with a quantifiable concentration;

[0164] AUC0-9: area under the plasma concentration-time curve from time zero to 9 hours;

[0165] CL / F: apparent in vivo clearance (calculated only for eniluracil and capecitabine);

[0166] Vd / F: apparent volume of distribution (calculated only for eniluracil and capecitabine);

[0167] MRT: mean residence time;

[0168] λz: terminal elimination rate constant;

[0169] t1 / 2: terminal elimination half-life; and

[0170] • Additional PK parameters will be determined if deemed necessary and if the data permit.

[0171] Example 3. Pharmacokinetic (PK) results

[0172] A. Introduction:

[0173] As described above, a clinical trial was conducted (see, e.g., Example 2) to evaluate various pharmacokinetic parameters and safety of capecitabine (discussed in Example 4 below) in an effort to confirm the effects observed in the PDX mouse model (see, e.g., Example 1). Briefly, capecitabine was administered to patients with advanced refractory gastrointestinal (GI) tumors using a 7-day dosing + 7-day resting capecitabine regimen approximately 24 hours after a single, fixed, oral dose of 40 mg eniluracil. The results obtained in the clinical trial were compared with data reported in Roche's Xeloda new drug application for FDA marketing approval (sometimes referred to herein as the "Xeloda study"), which are summarized in Table 1 above.

[0174] In the Xeloda study, 1255 mg / m2 was administered twice daily (bid). 2 Capecitabine, and in 8 cancer patients receiving the recommended dose of capecitabine (1255 mg / m 2 Various pharmacokinetic (PK) parameters were assessed in plasma at steady state (day 14) after 1-2 doses of 5'-DFCR, 5'-DFUR, 5-FU, FUH2, and FBAL in the Xeloda study. max (μg / mL), t max (h), AUC 0-t (μg*h / mL), AUC 0-∞ (μg*h / mL) and t 1 / 2 (h).

[0175] The results of the Xeloda study are similar to those described in the EMA 2005 Scientific Discussion for Registration of Xeloda in Europe. Briefly, in the 2005 EMA for Xeloda, peak plasma concentrations (C max In the 2005EMA of Xeloda, the time to peak plasma concentration (t max In the 2005EMA of Xeloda, the AUC in μg*h / mL was 1.50, 2.00, 2.00, 2.00 and 3.34 respectively. 0-∞ The values are 7.75, 7.24, 24.6, 2.03 and 36.3 respectively.

[0176] B. 5-FU:

[0177] It was determined that 5-FU levels were greatly increased in patients who received eniluracil pretreatment on day 1 followed by escalating doses of capecitabine on day 2. The AUC and C values of 5-FU in patients who received eniluracil pretreatment were significantly higher than those observed in patients who received capecitabine alone. max Level (respectively as Figure 2 and Figure 3 shown) are higher.

[0178] Assuming an average body surface area of 1.6 m 2 When capecitabine was taken at 1255 mg / m 2 When given at a dose of 1250 mg / m 2 A single dose of capecitabine is equivalent to 2000 mg per patient. 0-∞ Levels of 1255 mg / m 2 bid dosing is 1630 h*ng / mL and for 1250 mg / m 2 The mean AUC observed for the combination of eniluracil and capecitabine at a daily dose of 450 mg (225 mg bid) was 2030 h*ng / mL. 0-∞ The level was 5691 h*ng / mL. Therefore, a single dose of 225 mg of capecitabine (combined with pretreatment with eniluracil) provided a 2.8- to 3.5-fold increase in AUC, with a total dose of 1 / 8.9. Based on AUC comparisons, pretreatment with eniluracil increased the efficacy of capecitabine by 25- to 30-fold.

[0179] In the analysis of C max A potentiation effect of eniluracil was also observed in the AUC data, but was less robust than in the AUC data. A 225 mg dose of capecitabine (with pretreatment with eniluracil) produced a Cmax of 1082 ng / mL, compared with 709 ng / mL and 950 ng / mL for capecitabine alone.

[0180] Another major difference in the PK of 5-FU observed on day 2 when eniluracil was co-administered with capecitabine was the half-life (T 1 / 2 The half-life increased from 0.76 hours (capecitabine alone) to 5.71 hours (capecitabine combined with eniluracil pretreatment). The prolonged half-life of 5-FU contributed to the increased AUC observed with combination therapy.

[0181] Table 4.

[0182]

[0183] However, on day 8, no significant differences in AUC and C of eniluracil against 5-FU were observed. max The impact of Figure 4 and Figure 5 The AUC and C of 5-FU were max Levels are reduced, and the half-life and T max Values were comparable to those of capecitabine alone.

[0184] C. FBAL:

[0185] In general, the effect of pretreatment with eniluracil on the metabolism of capecitabine to FBAL was opposite to that observed for 5-FU. Essentially, although 5-FU exposure was greatly increased by eniluracil, FBAL levels were barely detectable on day 2. AUC and C max All parameters showed that eniluracil completely blocked the metabolism of capecitabine to FBAL even at the highest dose evaluated ( Figure 6 and Figure 7 shown).

[0186] Pretreatment with eniluracil also caused T in FBAL on day 2. max Increased (7-8 hours compared to 3.24 hours with capecitabine alone).

[0187] Similar to the results obtained for 5-FU, the effect of eniluracil on FBAL metabolism was no longer significant on day 8. max and parameters were proportional to the levels observed with capecitabine treatment alone (respectively Figure 8 and Figure 9 shown).

[0188] D. Capecitabine and other metabolites:

[0189] Pretreatment with eniluracil did not significantly affect the PK values of capecitabine, 5-DCFR, and 5'DFUR, as the AUC and C values of capecitabine were significantly different when the daily dose of capecitabine was 450 mg. max Values (capecitabine- Figure 10 and Figure 11 ;DFCR—respectively Figure 12 and Figure 13 ;DFUR- respectively Figure 14 and Figure 15 ) is with an estimated daily dose of approximately 4000-4500 mg (1255 mg / m 2 The efficacy of capecitabine (alone) was approximately 10-15 times higher than that of capecitabine (alone) when compared with capecitabine (alone) when administered twice daily.

[0190] E. Variability of PK parameters:

[0191] As mentioned in Xeloda's FDA and EMA regulatory submissions, the PK parameters of capecitabine and its metabolites (e.g., AUC and C max ) is highly variable. This high variability occurs even in patients whose capecitabine doses have been adjusted based on their body surface area (body surface area adjustment (BSA)). A problem associated with capecitabine in clinical practice is the need to individualize the treatment dose for each patient.

[0192] In the current clinical trial, capecitabine was given to patients at a fixed dose and therefore was not adjusted individually.The data generated for 5-FU on day 2 showed very low levels of variability (15%-30%).

[0193] Table 5.

[0194]

[0195] Table 6.

[0196]

[0197] Example 4. Safety and Efficacy Results

[0198] A. Introduction:

[0199] Clinical trials were conducted generally as described above (see, e.g., Example 2) to evaluate various pharmacokinetic parameters (discussed in Example 3 above) and safety of capecitabine in an effort to confirm the effects observed in the PDX mouse model (see, e.g., Example 1). Briefly, capecitabine was administered to patients with advanced, refractory gastrointestinal (GI) tumors using a 7-day on-dose + 7-day off capecitabine regimen approximately 24 hours after a single, fixed, oral dose of 40 mg eniluracil.

[0200] B. Patient demographics, cancer type, and number of cycles:

[0201] Table 7 below shows a summary of patient cohorts (1, 2A, 3, and 4). All patients had advanced cancer and, except for one patient in cohort 3, had completed more than 2 cycles of treatment at the cutoff point for data collection.

[0202] Table 7.

[0203]

[0204] C. Adverse events with Xeloda / capecitabine:

[0205] The Xeloda labeling contains the following warnings and precautions:

[0206] "Acute renal failure secondary to dehydration may be fatal. If Grade 2 (or higher) dehydration occurs, XELODA treatment should be interrupted immediately and the dehydration corrected…."

[0207] "Similar to other fluoropyrimidines, sudden death due to cardiotoxicity has been observed with XELODA..."

[0208] "XELODA can induce severe skin reactions such as hand-foot syndrome, Stevens-Johnson syndrome, and toxic epidermal necrolysis. If a Grade 2 (or higher) event occurs, XELODA administration should be interrupted immediately..."

[0209] "Rare, unexpected severe toxicities associated with 5-FU (e.g., stomatitis, diarrhea, mucosal inflammation, neutropenia, and neurotoxicity) have been attributed to a lack of DPD activity. Fatalities have been reported…."

[0210] "Altered coagulation parameters and / or bleeding have been reported in patients taking XELODA concomitantly with coumarin-derived anticoagulants (such as warfarin). Patients taking coumarin-derived anticoagulants concomitantly with XELODA should have their coagulation parameters (PT or INR) regularly monitored for changes, and the anticoagulant dose adjusted accordingly..."

[0211] In addition, it contains the following statement: “If toxicity emerges during treatment, XELODA should be interrupted until the event resolves or, if any of the following toxicities occur and are of Grade 2 or higher severity, becomes less severe: diarrhea, hand-foot syndrome, nausea, hyperbilirubinemia, vomiting, or stomatitis….”

[0212] Table 8 below details the most commonly observed adverse drug reactions in Xeloda registration clinical trials.

[0213] Table 8.

[0214] Summary of ADRs reported in ≥5% of patients with colon cancer tested with XELODA monotherapy or intravenous 5-FU / LV in the adjuvant setting.

[0215]

[0216]

[0217] *Mayo C lime regimen

[0218] **Based on postmarketing experience, persistent or severe palmar-plantar erythrodysesthesia syndrome (Grade 2 or higher) may ultimately lead to loss of fingerprints (see WARNINGS AND PRECAUTIONS).

[0219] D. Adverse events in clinical trials:

[0220] Table 9 below shows adverse events (Grade 2 or higher) observed in Cohorts 1, 2A, 3, and 4.

[0221] Table 9.

[0222]

[0223]

[0224] Although the limited number of patients treated at each dose makes any safety analysis difficult, it is noteworthy that no Grade 2 HFS, diarrhea, nausea, vomiting, or stomatitis were observed in the 11 patients treated with the combination of eniluracil and capecitabine at the various doses evaluated. These Grade 2 AEs are indicated in the Xeloda label and are the main cause of treatment delays, interruptions, and dose reductions for Xeloda (capecitabine). Since HFS was observed in approximately 60% of patients and diarrhea in approximately 46% of patients in Xeloda clinical trials, the complete absence of Grade 2 AEs in the current clinical trials is very encouraging, considering that many patients undergo multiple cycles of treatment.

[0225] E. Initial response rate:

[0226] Table 10 below contains some data regarding the RECIST analysis of lesions observed in patients enrolled in the clinical trial.

[0227] Table 10.

[0228]

[0229]

[0230] Because the clinical trial is still ongoing, it is premature to make any meaningful considerations about clinical efficacy. Patients in cohort 1 (102-101), who received 75 mg of capecitabine daily for the first seven cycles and then 75 mg twice daily for the remaining cycles, have been treated for a total of 24 cycles, corresponding to nearly a year of treatment. During this time, the patients demonstrated stable disease. Furthermore, patients 107-115 and 107-116 were treated for multiple cycles and demonstrated stable disease.

[0231] References:

[0232] [1]Schilsky et al., 1998, J. Clin Oncol 4: 1450-7.

[0233] [2]Schüller J,et al.,2000,Cancer Chemother Pharmacol.291-7.

[0234] [3]FDA,U.S.2001.Drug Approval Package:Xeloda.430. www.accessdata.fda.gov / drugsatfda_docs / nda / 2001 / 20896s6_Xeloda.cfm

[0235] [4]Roche Canada.2017.″Xeloda(capecitabine)Product Monograph.″1-59.

[0236] [5]Rivera E,et al.2014,Clin.Breast Cancer 14(1):26-30.

[0237] [6]Fiebig HH:Comparison of Tumor Responsein Nude Mice andinPatients.In:Winograd B,Peckham MJ,Pinedo HM(eds),Human Tumour Xenografts inAnticancer Drug Development.Berlin,Springer,1988,25-30.

[0238] [7]Fiebig HH,et al:Combinedin Vitro / in Vivo Test Procedure with HumanTumor Xenografts for New Drug Development.In:Fiebig HH,Berger DP(eds.),Immunodeficient Mice in Oncology.Contrib.Oncol.Basel,Karger,1992,42:321-351.

[0239] [8]Schueler J, et al: Patient-derived renal cell carcinoma xenografts exhibit distinct sensitivity patterns in response to antiangiogenic therapy and constitute a suitable tool for biomarker development. Oncotarget, 2018, 9(57): 30946-30961.

[0240] The invention and the manner and process of making and using the same are now described in such full, clear, concise, and precise terms as to enable any person skilled in the art to which the invention pertains to make and use the same. It will be understood that the foregoing describes preferred embodiments of the invention and that modifications may be made therein without departing from the scope of the invention as set forth in the claims. To particularly point out and distinctly claim the subject matter regarded as the invention, the following claims form the conclusion of the specification.

Claims

1. A method for treating cancer in a human subject, comprising: (a) orally administering eniluracil to the subject at a dose of 30-60 mg / day; (b) orally administering to the subject a fixed dose of about 140-700 mg / day of capecitabine or a dose of capecitabine that provides a 5-FU exposure (AUC) of about 1500 h*ng / mL or greater for 2-14 consecutive days after at least 10 hours of step (a); and (c) 3-14 days after step (b), repeating steps (a) and (b).

2. The method of claim 1, wherein eniluracil is administered at a dose of about 40 mg / day.

3. The method of claim 1, wherein capecitabine is administered at a dose of about 160-500 mg / day.

4. The method of claim 1, wherein step (b) occurs at least 17 hours after step (a).

5. The method of claim 1, wherein step (b) occurs 10-24 hours after step (a).

6. The method of claim 1, wherein step (c) occurs 7 days after step (b).

7. The method of claim 1, wherein the cancer is colorectal cancer, gastrointestinal tumor, breast cancer, pancreatic cancer, head and neck cancer, lung cancer, or advanced biliary tract cancer.

Images