Monotherapy (Metastatic Colorectal Cancer, Adjuvant Colorectal Cancer, Metastatic Breast Cancer)

The recommended dose of XELODA is 1250 mg/m2 administered orally twice daily (morning and evening; equivalent to 2500 mg/m2 total daily dose) for 2 weeks followed by a 1-week rest period given as 3-week cycles (see Table 1).

Adjuvant treatment in patients with Dukes' C colon cancer is recommended for a total of 6 months [ie, XELODA 1250 mg/m2 orally twice daily for 2 weeks followed by a 1-week rest period, given as 3-week cycles for a total of 8 cycles (24 weeks)].

In Combination With Docetaxel (Metastatic Breast Cancer)

In combination with docetaxel, the recommended dose of XELODA is 1250 mg/m2 twice daily for 2 weeks followed by a 1-week rest period, combined with docetaxel at 75 mg/m2 as a 1-hour intravenous infusion every 3 weeks. Pre-medication, according to the docetaxel labeling, should be started prior to docetaxel administration for patients receiving the XELODA plus docetaxel combination. Table 1 displays the total daily dose of XELODA by body surface area and the number of tablets to be taken at each dose.

General

XELODA dosage may need to be individualized to optimize patient management. Patients should be carefully monitored for toxicity and doses of XELODA should be modified as necessary to accommodate individual patient tolerance to treatment [see Clinical Studies (14)]. Toxicity due to XELODA administration may be managed by symptomatic treatment, dose interruptions and adjustment of XELODA dose. Once the dose has been reduced, it should not be increased at a later time. Doses of XELODA omitted for toxicity are not replaced or restored; instead the patient should resume the planned treatment cycles.

The dose of phenytoin and the dose of coumarin-derivative anticoagulants may need to be reduced when either drug is administered concomitantly with XELODA [see Drug Interactions (7.1)].

Monotherapy (Metastatic Colorectal Cancer, Adjuvant Colorectal Cancer, Metastatic Breast Cancer)

XELODA dose modification scheme as described below (see Table 2) is recommended for the management of adverse reactions.

In Combination With Docetaxel (Metastatic Breast Cancer)

Dose modifications of XELODA for toxicity should be made according to Table 2 above for XELODA. At the beginning of a treatment cycle, if a treatment delay is indicated for either XELODA or docetaxel, then administration of both agents should be delayed until the requirements for restarting both drugs are met.

The dose reduction schedule for docetaxel when used in combination with XELODA for the treatment of metastatic breast cancer is shown in Table 3.

Renal Impairment

No adjustment to the starting dose of XELODA is recommended in patients with mild renal impairment (creatinine clearance = 51 to 80 mL/min [Cockroft and Gault, as shown below]). In patients with moderate renal impairment (baseline creatinine clearance = 30 to 50 mL/min), a dose reduction to 75% of the XELODA starting dose when used as monotherapy or in combination with docetaxel (from 1250 mg/m2 to 950 mg/m2 twice daily) is recommended [see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3)]. Subsequent dose adjustment is recommended as outlined in Table 2 and Table 3 (depending on the regimen) if a patient develops a grade 2 to 4 adverse event [see Warnings and Precautions (5.5)]. The starting dose adjustment recommendations for patients with moderate renal impairment apply to both XELODA monotherapy and XELODA in combination use with docetaxel.

Geriatrics

Physicians should exercise caution in monitoring the effects of XELODA in the elderly. Insufficient data are available to provide a dosage recommendation.

Monotherapy

Table 6 shows the adverse reactions occurring in ≥5% of patients from pooling the two phase 3 trials in first line metastatic colorectal cancer. A total of 596 patients with metastatic colorectal cancer were treated with 1250 mg/m2 twice a day of XELODA administered for 2 weeks followed by a 1-week rest period, and 593 patients were administered 5-FU and leucovorin in the Mayo regimen (20 mg/m2 leucovorin IV followed by 425 mg/m2 IV bolus 5-FU, on days 1-5, every 28 days). In the pooled colorectal database the median duration of treatment was 139 days for capecitabine-treated patients and 140 days for 5-FU/LV-treated patients. A total of 78 (13%) and 63 (11%) capecitabine and 5-FU/LV-treated patients, respectively, discontinued treatment because of adverse reactions/intercurrent illness. A total of 82 deaths due to all causes occurred either on study or within 28 days of receiving study drug: 50 (8.4%) patients randomized to XELODA and 32 (5.4%) randomized to 5-FU/LV.

In Combination with Docetaxel

The following data are shown for the combination study with XELODA and docetaxel in patients with metastatic breast cancer in Table 7 and Table 8. In the XELODA and docetaxel combination arm the treatment was XELODA administered orally 1250 mg/m2 twice daily as intermittent therapy (2 weeks of treatment followed by 1 week without treatment) for at least 6 weeks and docetaxel administered as a 1-hour intravenous infusion at a dose of 75 mg/m2 on the first day of each 3-week cycle for at least 6 weeks. In the monotherapy arm docetaxel was administered as a 1-hour intravenous infusion at a dose of 100 mg/m2 on the first day of each 3-week cycle for at least 6 weeks. The mean duration of treatment was 129 days in the combination arm and 98 days in the monotherapy arm. A total of 66 patients (26%) in the combination arm and 49 (19%) in the monotherapy arm withdrew from the study because of adverse reactions. The percentage of patients requiring dose reductions due to adverse reactions was 65% in the combination arm and 36% in the monotherapy arm. The percentage of patients requiring treatment interruptions due to adverse reactions in the combination arm was 79%. Treatment interruptions were part of the dose modification scheme for the combination therapy arm but not for the docetaxel monotherapy-treated patients.

Monotherapy

The following data are shown for the study in stage IV breast cancer patients who received a dose of 1250 mg/m2 administered twice daily for 2 weeks followed by a 1-week rest period. The mean duration of treatment was 114 days. A total of 13 out of 162 patients (8%) discontinued treatment because of adverse reactions/intercurrent illness.

Monotherapy (Metastatic Colorectal Cancer, Adjuvant Colorectal Cancer, Metastatic Breast Cancer)

XELODA In Combination With Docetaxel (Metastatic Breast Cancer)

Anticoagulants

Altered coagulation parameters and/or bleeding have been reported in patients taking XELODA concomitantly with coumarin-derivative anticoagulants such as warfarin and phenprocoumon [see Boxed Warning]. These events occurred within several days and up to several months after initiating XELODA therapy and, in a few cases, within 1 month after stopping XELODA. These events occurred in patients with and without liver metastases. In a drug interaction study with single-dose warfarin administration, there was a significant increase in the mean AUC of S-warfarin [see Clinical Pharmacology (12.3)]. The maximum observed INR value increased by 91%. This interaction is probably due to an inhibition of cytochrome P450 2C9 by capecitabine and/or its metabolites.

Phenytoin

The level of phenytoin should be carefully monitored in patients taking XELODA and phenytoin dose may need to be reduced [see Dosage and Administration (2.2)]. Postmarketing reports indicate that some patients receiving XELODA and phenytoin had toxicity associated with elevated phenytoin levels. Formal drug-drug interaction studies with phenytoin have not been conducted, but the mechanism of interaction is presumed to be inhibition of the CYP2C9 isoenzyme by capecitabine and/or its metabolites.

Leucovorin

The concentration of 5-fluorouracil is increased and its toxicity may be enhanced by leucovorin. Deaths from severe enterocolitis, diarrhea, and dehydration have been reported in elderly patients receiving weekly leucovorin and fluorouracil.

CYP2C9 substrates

Other than warfarin, no formal drug-drug interaction studies between XELODA and other CYP2C9 substrates have been conducted. Care should be exercised when XELODA is coadministered with CYP2C9 substrates.

XELODA can cause fetal harm when administered to a pregnant woman. Capecitabine at doses of 198 mg/kg/day during organogenesis caused malformations and embryo death in mice. In separate pharmacokinetic studies, this dose in mice produced 5'-DFUR AUC values about 0.2 times the corresponding values in patients administered the recommended daily dose. Malformations in mice included cleft palate, anophthalmia, microphthalmia, oligodactyly, polydactyly, syndactyly, kinky tail and dilation of cerebral ventricles. At doses of 90 mg/kg/day, capecitabine given to pregnant monkeys during organogenesis caused fetal death. This dose produced 5'-DFUR AUC values about 0.6 times the corresponding values in patients administered the recommended daily dose.

There are no adequate and well controlled studies of XELODA in pregnant women. If this drug is used during pregnancy, or if a patient becomes pregnant while receiving XELODA, the patient should be apprised of the potential hazard to the fetus. Women should be advised to avoid becoming pregnant while receiving treatment with XELODA [see Warnings and Precautions (5.6)].

Absorption

Following oral administration of 1255 mg/m2 BID to cancer patients, capecitabine reached peak blood levels in about 1.5 hours (Tmax) with peak 5-FU levels occurring slightly later, at 2 hours. Food reduced both the rate and extent of absorption of capecitabine with mean Cmax and AUC0-∞ decreased by 60% and 35%, respectively. The Cmax and AUC0-∞ of 5-FU were also reduced by food by 43% and 21%, respectively. Food delayed Tmax of both parent and 5-FU by 1.5 hours [see Warnings and Precautions (5), Dosage and Administration (2), and Drug-Food Interaction (7.2)].

The pharmacokinetics of XELODA and its metabolites have been evaluated in about 200 cancer patients over a dosage range of 500 to 3500 mg/m2/day. Over this range, the pharmacokinetics of XELODA and its metabolite, 5'-DFCR were dose proportional and did not change over time. The increases in the AUCs of 5'-DFUR and 5-FU, however, were greater than proportional to the increase in dose and the AUC of 5-FU was 34% higher on day 14 than on day 1. The interpatient variability in the Cmax and AUC of 5-FU was greater than 85%.

Distribution

Plasma protein binding of capecitabine and its metabolites is less than 60% and is not concentration-dependent. Capecitabine was primarily bound to human albumin (approximately 35%). XELODA has a low potential for pharmacokinetic interactions related to plasma protein binding.

Bioactivation and Metabolism

Capecitabine is extensively metabolized enzymatically to 5-FU. In the liver, a 60 kDa carboxylesterase hydrolyzes much of the compound to 5'-deoxy-5-fluorocytidine (5'-DFCR). Cytidine deaminase, an enzyme found in most tissues, including tumors, subsequently converts 5'-DFCR to 5'-DFUR. The enzyme, thymidine phosphorylase (dThdPase), then hydrolyzes 5'-DFUR to the active drug 5-FU. Many tissues throughout the body express thymidine phosphorylase. Some human carcinomas express this enzyme in higher concentrations than surrounding normal tissues. Following oral administration of XELODA 7 days before surgery in patients with colorectal cancer, the median ratio of 5-FU concentration in colorectal tumors to adjacent tissues was 2.9 (range from 0.9 to 8.0). These ratios have not been evaluated in breast cancer patients or compared to 5-FU infusion.

Metabolic Pathway of capecitabine to 5-FU

The enzyme dihydropyrimidine dehydrogenase hydrogenates 5-FU, the product of capecitabine metabolism, to the much less toxic 5-fluoro-5, 6-dihydro-fluorouracil (FUH2). Dihydropyrimidinase cleaves the pyrimidine ring to yield 5-fluoro-ureido-propionic acid (FUPA). Finally, β-ureido-propionase cleaves FUPA to α-fluoro-β-alanine (FBAL) which is cleared in the urine.

In vitro enzymatic studies with human liver microsomes indicated that capecitabine and its metabolites (5'-DFUR, 5'-DFCR, 5-FU, and FBAL) did not inhibit the metabolism of test substrates by cytochrome P450 isoenzymes 1A2, 2A6, 3A4, 2C19, 2D6, and 2E1.

Excretion

Capecitabine and its metabolites are predominantly excreted in urine; 95.5% of administered capecitabine dose is recovered in urine. Fecal excretion is minimal (2.6%). The major metabolite excreted in urine is FBAL which represents 57% of the administered dose. About 3% of the administered dose is excreted in urine as unchanged drug. The elimination half-life of both parent capecitabine and 5-FU was about 0.75 hour.

Effect of Age, Gender, and Race on the Pharmacokinetics of Capecitabine

A population analysis of pooled data from the two large controlled studies in patients with metastatic colorectal cancer (n=505) who were administered XELODA at 1250 mg/m2 twice a day indicated that gender (202 females and 303 males) and race (455 white/Caucasian patients, 22 black patients, and 28 patients of other race) have no influence on the pharmacokinetics of 5'-DFUR, 5-FU and FBAL. Age has no significant influence on the pharmacokinetics of 5'-DFUR and 5-FU over the range of 27 to 86 years. A 20% increase in age results in a 15% increase in AUC of FBAL [see Warnings and Precautions (5.11) and Dosage and Administration (2.3)].

Following oral administration of 825 mg/m2 capecitabine twice daily for 14 days, Japanese patients (n=18) had about 36% lower Cmax and 24% lower AUC for capecitabine than the Caucasian patients (n=22). Japanese patients had also about 25% lower Cmax and 34% lower AUC for FBAL than the Caucasian patients. The clinical significance of these differences is unknown. No significant differences occurred in the exposure to other metabolites (5'-DFCR, 5'-DFUR, and 5-FU).

Effect of Hepatic Insufficiency

XELODA has been evaluated in 13 patients with mild to moderate hepatic dysfunction due to liver metastases defined by a composite score including bilirubin, AST/ALT and alkaline phosphatase following a single 1255 mg/m2 dose of XELODA. Both AUC0-∞ and Cmax of capecitabine increased by 60% in patients with hepatic dysfunction compared to patients with normal hepatic function (n=14). The AUC0-∞ and Cmax of 5-FU were not affected. In patients with mild to moderate hepatic dysfunction due to liver metastases, caution should be exercised when XELODA is administered. The effect of severe hepatic dysfunction on XELODA is not known [see Warnings and Precautions (5.11) and Use in Special Populations (8.6)].

Effect of Renal Insufficiency

Following oral administration of 1250 mg/m2 capecitabine twice a day to cancer patients with varying degrees of renal impairment, patients with moderate (creatinine clearance = 30 to 50 mL/min) and severe (creatinine clearance <30 mL/min) renal impairment showed 85% and 258% higher systemic exposure to FBAL on day 1 compared to normal renal function patients (creatinine clearance >80 mL/min). Systemic exposure to 5'-DFUR was 42% and 71% greater in moderately and severely renal impaired patients, respectively, than in normal patients. Systemic exposure to capecitabine was about 25% greater in both moderately and severely renal impaired patients [see Dosage and Administration (2.3), Contraindications (4.2), Warnings and Precautions (5.5), and Use in Special Populations (8.7)].

Effect of Capecitabine on the Pharmacokinetics of Warfarin

In four patients with cancer, chronic administration of capecitabine (1250 mg/m2 bid) with a single 20 mg dose of warfarin increased the mean AUC of S-warfarin by 57% and decreased its clearance by 37%. Baseline corrected AUC of INR in these 4 patients increased by 2.8-fold, and the maximum observed mean INR value was increased by 91% [see Boxed Warning and Drug Interactions (7.1)].

Effect of Antacids on the Pharmacokinetics of Capecitabine

When Maalox® (20 mL), an aluminum hydroxide- and magnesium hydroxide-containing antacid, was administered immediately after XELODA (1250 mg/m2, n=12 cancer patients), AUC and Cmax increased by 16% and 35%, respectively, for capecitabine and by 18% and 22%, respectively, for 5'-DFCR. No effect was observed on the other three major metabolites (5'-DFUR, 5-FU, FBAL) of XELODA.

Effect of Capecitabine on the Pharmacokinetics of Docetaxel and Vice Versa

A Phase 1 study evaluated the effect of XELODA on the pharmacokinetics of docetaxel (Taxotere®) and the effect of docetaxel on the pharmacokinetics of XELODA was conducted in 26 patients with solid tumors. XELODA was found to have no effect on the pharmacokinetics of docetaxel (Cmax and AUC) and docetaxel has no effect on the pharmacokinetics of capecitabine and the 5-FU precursor 5'-DFUR.

Impairment of Fertility

In studies of fertility and general reproductive performance in female mice, oral capecitabine doses of 760 mg/kg/day (about 2300 mg/m2/day) disturbed estrus and consequently caused a decrease in fertility. In mice that became pregnant, no fetuses survived this dose. The disturbance in estrus was reversible. In males, this dose caused degenerative changes in the testes, including decreases in the number of spermatocytes and spermatids. In separate pharmacokinetic studies, this dose in mice produced 5'-DFUR AUC values about 0.7 times the corresponding values in patients administered the recommended daily dose.

General

The recommended dose of XELODA was determined in an open-label, randomized clinical study, exploring the efficacy and safety of continuous therapy with capecitabine (1331 mg/m2/day in two divided doses, n=39), intermittent therapy with capecitabine (2510 mg/m2/day in two divided doses, n=34), and intermittent therapy with capecitabine in combination with oral leucovorin (LV) (capecitabine 1657 mg/m2/day in two divided doses, n=35; leucovorin 60 mg/day) in patients with advanced and/or metastatic colorectal carcinoma in the first-line metastatic setting. There was no apparent advantage in response rate to adding leucovorin to XELODA; however, toxicity was increased. XELODA, 1250 mg/m2 twice daily for 14 days followed by a 1-week rest, was selected for further clinical development based on the overall safety and efficacy profile of the three schedules studied.

Monotherapy

Data from two open-label, multicenter, randomized, controlled clinical trials involving 1207 patients support the use of XELODA in the first-line treatment of patients with metastatic colorectal carcinoma. The two clinical studies were identical in design and were conducted in 120 centers in different countries. Study 1 was conducted in the US, Canada, Mexico, and Brazil; Study 2 was conducted in Europe, Israel, Australia, New Zealand, and Taiwan. Altogether, in both trials, 603 patients were randomized to treatment with XELODA at a dose of 1250 mg/m2 twice daily for 2 weeks followed by a 1-week rest period and given as 3-week cycles; 604 patients were randomized to treatment with 5-FU and leucovorin (20 mg/m2 leucovorin IV followed by 425 mg/m2 IV bolus 5-FU, on days 1 to 5, every 28 days).

In both trials, overall survival, time to progression and response rate (complete plus partial responses) were assessed. Responses were defined by the World Health Organization criteria and submitted to a blinded independent review committee (IRC). Differences in assessments between the investigator and IRC were reconciled by the sponsor, blinded to treatment arm, according to a specified algorithm. Survival was assessed based on a non-inferiority analysis.

The baseline demographics for XELODA and 5-FU/LV patients are shown in Table 13.

The efficacy endpoints for the two phase 3 trials are shown in Table 14 and Table 15.

Figure 3 Kaplan-Meier Curve for Overall Survival of Pooled Data (Studies 1 and 2)

XELODA was superior to 5-FU/LV for objective response rate in Study 1 and Study 2. The similarity of XELODA and 5-FU/LV in these studies was assessed by examining the potential difference between the two treatments. In order to assure that XELODA has a clinically meaningful survival effect, statistical analyses were performed to determine the percent of the survival effect of 5-FU/LV that was retained by XELODA. The estimate of the survival effect of 5-FU/LV was derived from a meta-analysis of ten randomized studies from the published literature comparing 5-FU to regimens of 5-FU/LV that were similar to the control arms used in these Studies 1 and 2. The method for comparing the treatments was to examine the worst case (95% confidence upper bound) for the difference between 5-FU/LV and XELODA, and to show that loss of more than 50% of the 5-FU/LV survival effect was ruled out. It was demonstrated that the percent of the survival effect of 5-FU/LV maintained was at least 61% for Study 2 and 10% for Study 1. The pooled result is consistent with a retention of at least 50% of the effect of 5-FU/LV. It should be noted that these values for preserved effect are based on the upper bound of the 5-FU/LV vs XELODA difference. These results do not exclude the possibility of true equivalence of XELODA to 5-FU/LV (see Table 14, Table 15, and Figure 3).

In Combination With Docetaxel

The dose of XELODA used in the phase 3 clinical trial in combination with docetaxel was based on the results of a phase 1 study, where a range of doses of docetaxel administered in 3-week cycles in combination with an intermittent regimen of XELODA (14 days of treatment, followed by a 7-day rest period) were evaluated. The combination dose regimen was selected based on the tolerability profile of the 75 mg/m2 administered in 3-week cycles of docetaxel in combination with 1250 mg/m2 twice daily for 14 days of XELODA administered in 3-week cycles. The approved dose of 100 mg/m2 of docetaxel administered in 3-week cycles was the control arm of the phase 3 study.

XELODA in combination with docetaxel was assessed in an open-label, multicenter, randomized trial in 75 centers in Europe, North America, South America, Asia, and Australia. A total of 511 patients with metastatic breast cancer resistant to, or recurring during or after an anthracycline-containing therapy, or relapsing during or recurring within 2 years of completing an anthracycline-containing adjuvant therapy were enrolled. Two hundred and fifty-five (255) patients were randomized to receive XELODA 1250 mg/m2 twice daily for 14 days followed by 1 week without treatment and docetaxel 75 mg/m2 as a 1-hour intravenous infusion administered in 3-week cycles. In the monotherapy arm, 256 patients received docetaxel 100 mg/m2 as a 1-hour intravenous infusion administered in 3-week cycles. Patient demographics are provided in Table 16.

XELODA in combination with docetaxel resulted in statistically significant improvement in time to disease progression, overall survival and objective response rate compared to monotherapy with docetaxel as shown in Table 17, Figure 4, and Figure 5.

Figure 4 Kaplan-Meier Estimates for Time to Disease Progression XELODA and Docetaxel vs Docetaxel

Figure 5 Kaplan-Meier Estimates of Survival XELODA and Docetaxel vs Docetaxel

Monotherapy

The antitumor activity of XELODA as a monotherapy was evaluated in an open-label single-arm trial conducted in 24 centers in the US and Canada. A total of 162 patients with stage IV breast cancer were enrolled. The primary endpoint was tumor response rate in patients with measurable disease, with response defined as a ≥50% decrease in sum of the products of the perpendicular diameters of bidimensionally measurable disease for at least 1 month. XELODA was administered at a dose of 1255 mg/m2 twice daily for 2 weeks followed by a 1-week rest period and given as 3-week cycles. The baseline demographics and clinical characteristics for all patients (n=162) and those with measurable disease (n=135) are shown in Table 18. Resistance was defined as progressive disease while on treatment, with or without an initial response, or relapse within 6 months of completing treatment with an anthracycline-containing adjuvant chemotherapy regimen.

Antitumor responses for patients with disease resistant to both paclitaxel and an anthracycline are shown in Table 19.

For the subgroup of 43 patients who were doubly resistant, the median time to progression was 102 days and the median survival was 255 days. The objective response rate in this population was supported by a response rate of 18.5% (1 CR, 24 PRs) in the overall population of 135 patients with measurable disease, who were less resistant to chemotherapy (see Table 18). The median time to progression was 90 days and the median survival was 306 days.

Diarrhea

Patients experiencing grade 2 diarrhea (an increase of 4 to 6 stools/day or nocturnal stools) or greater should be instructed to stop taking XELODA immediately. Standard antidiarrheal treatments (eg, loperamide) are recommended.

Nausea

Patients experiencing grade 2 nausea (food intake significantly decreased but able to eat intermittently) or greater should be instructed to stop taking XELODA immediately. Initiation of symptomatic treatment is recommended.

Vomiting

Patients experiencing grade 2 vomiting (2 to 5 episodes in a 24-hour period) or greater should be instructed to stop taking XELODA immediately. Initiation of symptomatic treatment is recommended.

Hand-and-Foot Syndrome

Patients experiencing grade 2 hand-and-foot syndrome (painful erythema and swelling of the hands and/or feet and/or discomfort affecting the patients' activities of daily living) or greater should be instructed to stop taking XELODA immediately.

Stomatitis

Patients experiencing grade 2 stomatitis (painful erythema, edema or ulcers of the mouth or tongue, but able to eat) or greater should be instructed to stop taking XELODA immediately. Initiation of symptomatic treatment is recommended [see Dosage and Administration (2.2)].

Fever and Neutropenia

Patients who develop a fever of 100.5°F or greater or other evidence of potential infection should be instructed to call their physician.