A phase II study of UFT with leucovorin administered as a twice daily schedule in the treatment of patients with metastatic colorectal cancer

Prolonged infusions have been shown to be safer and potentially more effective than bolus regimens of 5-fluorouracil (5-FU) as treatment for metastatic colorectal cancer (mCRC). However, infusional 5-FU requires central venous access and costly infusion pumps. Oral fluoropyrimidines enable longer exposures to 5-FU with increased convenience. Tegafur–uracil (UFT) with leucovorin (LV) given thrice daily has improved safety plus comparable survival and response rates to bolus 5-FU/LV. We conducted a phase II clinical study in 98 patients with mCRC to evaluate if UFT with LV given twice daily provided comparable time to progression (TTP), efficacy and tolerability to that reported for thrice daily in two phase III clinical studies. Secondary objectives included overall response rate (ORR) and overall survival (OS). Median TTP was 3.8 months, when compared with 3.5 months for thrice daily. The ORR (11%) and median OS (12.8 months) with twice daily administration were similar to that of thrice daily administration (12% and 12.4 months). The incidence of grade 3/4 treatment-related diarrhoea was 30% on the twice daily and 21% on the thrice daily schedule. These results suggest that twice daily administration has similar efficacy and tolerability to thrice daily administration and is an acceptable alternative for patients who would benefit from UFT with LV therapy.

Phase II study of infusional 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) plus bevacizumab as first-line treatment for metastatic colorectal cancer

4089

Background: When compared to bolus 5-fluorouracil (F), leucovorin (L), and irinotecan (I) regimens such as IFL, the infusional F, L, I regimen (FOLFIRI) resulted in a improved toxicity profile with a response rate (RR) of 35% and median progression free survival (PFS) of 6.7 months. When combined with bevacizumab (B) as first-line treatment, IFL demonstrated improved activity with a RR of 45% and a median PFS of 10.6 months. Combining FOLFIRI and B may further improve the efficacy. Methods: We designed a single-arm, phase II trial of FOLFIRI+B with B (5mg/kg), I (180mg/m2), bolus of F (400mg/m2) and L (400mg/m2) with a 46-hour infusion of F (2400mg/m2) every 2 weeks. The primary endpoint was PFS. Chemotherapy naïve mCRC patients (pts) with a performance status of 0–2 received B alone on Day -14, starting FOLFIRI+B on Day 1. Proteomic and radiographic correlative studies were completed and will be reported separately. Results: N=41 pts, median age 56 y/o (range 26–78), M:F = 16:25, 5 pts with prior adjuvant therapy, were enrolled from 1/2005 to 1/2007. A total of 502 cycles have been administered (median = 12). The median PFS is 12.6 months. Response rate by intention-to-treat analysis was 62% (24 pts), with 33% stable disease (13 pts). Responses occurred after a median of 4 months of therapy. Fifteen pts remain on treatment; 26 pts are off study: 7 for progressive disease, 2 withdrew consent, 7 for toxicity and 2 for surgery unrelated to cancer. Eight pts were removed from the study for metastasectomies. Grade 3 or 4 toxicities included 17 occurrences of grade = 3 neutropenia, including 1 grade 4 febrile neutropenia, 4 grade 4 pulmonary emboli, 2 grade 3 hand-foot syndrome, and 1 grade 3 diarrhea. One pt included in the analysis developed a possible microperforation, manifested by peritonitis, after B alone and never received FOLFIRI. Conclusion: FOLFIRI+B is well-tolerated and efficacious, with an impressive PFS that compares favorably to historical controls. This regimen is an excellent choice as a first-line treatment for mCRC.

No significant financial relationships to disclose.

Lack of concordance between I-111 pentreotide (PEN) status and immuno-histochemistry (IHC) status for somatostatin receptors type 1, 2, and 3 in neuroendocrine tumors (NET)

15060

Background: The use of somatostatin analogues (ST) in the treatment of NET is recommended for functional and non- function slow progressing tumors that present with positive PEN. The goal of the study was to determine if expression of ST receptors type 2, 3 and 1 in NET tumors by IHC predict the PEN status and response to ST. Methods: Retrospective analysis of paraffin blocs from primary or metastatic sites and PEN imaging from 39 patients with a diagnosis of NET confirmed by independent pathology review. IHC analysis was performed in a central laboratory using antibody ST receptor type 1 from Neomarkers and type 2 and 3 from Affinity Bio Reagents. Status for each receptor type was reported as positive or negative, diffuse or focal and by % of positive cells. All slides were reviewed by the same pathologist. PEN images were submitted to an independent radiology review and reported as positive or negative and the signal intensity was graded from 1 to 4. Investigators were blinded to receptor and PEN status. This concordance analysis study was designed with a power to detect at least 60% correlation between receptor and PEN status with type I error of 5% and a type II error of 20%. Results: There was no correlation between receptor and PEN status ( Table ). Furthermore, there was no significant correlation between PEN and receptor types 3 and 1 in receptor type 2 negative patients (p=0,54, p=0,14, respectively). There was no correlation between receptor type status and PEN positive intensity. No independent or multivariate characteristics by IHC can correlate to PEN status in this cohort. Conclusions: Commonly used antibodies for IHC detection of receptors type 2, 3 and 1 used in this study failed to correlate with PEN. These results do not support the use of IHC as a substitute for PEN with respect to prediction of ST activity in NET.

[Table: see text]

No significant financial relationships to disclose.

A phase I trial of TAS-102 administered on a three times a day schedule in patients with solid tumors

2053

Background: TAS-102 consists of trifluorothymidine (FTD) and an inhibitor of thymidine phosphorylase (TP). FTD, like 5-fluorouracil, is an inhibitor of thymidylate synthase. However, when orally administered, FTD is rapidly degraded to an inactive form, primarily by TP. Co-administration of FTD with an inhibitor of TP elevates FTD concentrations. Since tumor xenograft models demonstrated greater anti-tumor activity with divided daily dosing of TAS-102, and a phase I trial of once-daily TAS-102 showed a short FTD half-life, this trial was designed to explore a three times a day dosing schedule. Methods: Patients with advanced solid tumors having received prior therapy, with adequate organ function, and performance status Zubrod 0–2, were eligible. TAS-102 was administered orally three times a day for 5 days a week for two weeks, followed by two weeks off. Courses were repeated every 4 weeks. Results: A total of 15 patients (8 female, age 37–72 years) were enrolled into the study; three at 60 mg/m2/day, 6 each at 70 mg/m2/day and 80 mg/m2/day. Nine patients had colorectal cancer, 2 carcinoma of unknown primary, 2 pancreatic cancer, one each medullary thyroid cancer and cholangiocarcinoma. Toxicity was assessed throughout all courses of therapy. Grade 3 and 4 hematological toxicities were the most common, including 3 episodes of grade 3 neutropenia at 60 mg/m2/day, 5 at 70 mg/m2/day, 5 at 80 mg/m2/day with only 1 instance of grade 3 thrombocytopenia at 80 mg/m2/day. Non-hematological grade 3 toxicities included nausea/vomiting (1 at 70 mg/m2/day), colitis, gout, and hematuria (1 each at 70 mg/m2/day), and fatigue (1 at 70 mg/m2/day and 2 at 80 mg/m2/day) Two episodes of dose-limiting toxicity were observed at 80 mg/m2/day: grade 3 fatigue and grade 4 neutropenia. Although there were no objective responses, nine patients (60%) maintained stable disease with a median duration of disease stabilization of 4.3 months (range, 1.9 to 8.6 months). Conclusions: TAS-102 is well tolerated with manageable hematologic toxicity and few non-hematological toxicities. The most common grade 3 or 4 toxicity was neutropenia. The suggested phase II dose of TAS-102 is 70 mg/m2/day when administered orally three times a day for 5 days a week for two weeks followed by two weeks off every 4 weeks.

[Table: see text]

Phase II trial of depsipeptide (NSC-630176) in colorectal cancer patients who have received either one or two prior chemotherapy regimens for metastatic or locally advanced, unresectable disease: A Southwest Oncology Group study

3598

The treatment for metastatic colorectal cancer has markedly improved but the disease is still not curable, and additional active agents need to be found. Depsipeptide is a histone deacetylase inhibitor that has shown activity against human solid tumor cell lines and promising results in murine model systems. This phase II trial was undertaken to determine its activity in patients with advanced colorectal cancer. Eligibility requirements included measurable disease, either metastatic or locally advanced and not surgically resectable, Zubrod performance status of 0–1, and adequate renal, hepatic, hematologic and cardiac function. Prior surgery or radiation therapy was allowed and patients were required to have received either one or two prior chemotherapy regimens for advanced disease. A two-stage design was used designed to detect a difference in the null hypothesis of 5% response vs. an alternative 20% response, with 20 eligible patients to be accrued initially followed by an additional 20 patients if one or more confirmed responses were observed. The study closed after the first stage, with 28 patients registered. Three patients are ineligible, two who did not meet requirements for serum magnesium level, and one whose baseline labs were performed more than 14 days prior to registration. One eligible patient never received treatment and is not analyzable for any endpoint. For the 24 eligible and analyzable patients, median age was 58.6 years (range 31–84) with 14 males. Performance status was 0 in 16 patients and 1 in 8. Ten patients received 1 prior chemotherapy regimen and 14 received 2 prior regimens. There were no grade 4 or higher toxicities. The most common grade 2 or 3 toxicities were anorexia, fatigue, nausea, and dehydration. No objective responses were observed. Four patients had stable disease, 15 showed increasing disease, 3 had symptomatic deterioration, and 2 had assessment inadequate. The current Kaplan-Meier estimate of 6 month overall survival is 69% (95% CI 50%-88%) with a median survival of 8.4 months. Depsipeptide does not show significant anti-tumor activity in previously treated patients with advanced colorectal cancer.

No significant financial relationships to disclose.

Phase I/II trial of capecitabine (C), dacarbazine (D) and imatinib (I) (CDI) for patients (pts) metastatic medullary thyroid carcinomas (MTC)

13048

Background: MTC is a rare tumor that responds poorly to conventional chemotherapy. 5-FU and D are frequently used, with an expected response rate of around 15%. MTC is often associated with multiple endocrine neoplasia type 2, an autosomal dominant syndrome caused by a mutation in the RET proto-oncogene which encodes RET, a tyrosine kinase receptor. I is a tyrosine kinase inhibitor with activity against c-Kit, PDGF and possibly RET, and we postulated that its addition to chemotherapy would increase its efficacy against this disease. Methods: We designed a phase I/II trial combining escalating doses of oral C, IV D and oral I. Pts with any advanced solid tumors were eligible for the phase I part of the trial. Results: 13 pts were entered and 12 were eligible (7 MTC, 2 adrenocortical, 1 islet-cell, 1 insular thyroid and 1 small cell). 4 pts did not complete one cycle (1 pt withdrew after 5 days and 2 pts progressed in less than 10 days and were replaced for toxicity analysis, 1 had a DLT and is included). 3 patients were entered in dose level 1, without DLT. 2 out of 6 pts developed DLT at the second dose level (1 G 3 fatigue and 1 G3 hypokalemia). Three additional pts are being entered on dose level 1. The first one had PD after 7 days and is being replaced. For the 11 pts who were evaluable, best response was 3 SD (range 3 to 9 + months) and 8 PD. Conclusions: The combination of CDI is feasible but has resulted in an unexpected pattern of toxicity in this patient population, with fatigue and hypokalemia as the DLT. No significant diarrhea or hand-foot syndrome was seen. Only G1 and 2 fluid retention and neutropenia have been encountered. Only minor reduction in tumor size has been seen among these heavily pretreated pts. Once the phase I is complete, the trial will continue in a phase II setting for untreated MTC pts.

[Table: see text]

[Table: see text]

Comparison of the efficacy, toxicity, and pharmacokinetics of a uracil/tegafur (UFT) plus oral leucovorin (LV) regimen between Japanese and American patients with advanced colorectal cancer: joint United States and Japan study of UFT/LV

PURPOSE

To compare the efficacy, toxicities, and pharmacokinetics of an oral regimen consisting of uracil/tegafur (UFT) and leucovorin (LV) between Japanese patients and patients in the United States with previously untreated metastatic colorectal cancer.

PATIENTS AND METHODS

Forty-four Japanese patients and 45 patients in the United States were enrolled in concurrent nonrandomized phase II trials. UFT 300 mg/m2/d and leucovorin 75 mg/d were administered orally for 28 days followed by a 7-day rest period. The total daily dose of each drug was divided into three equal doses. Treatment was repeated every 5 weeks until disease progression. Blood samples for the pharmacokinetic study were obtained after the initial dose on day 1 of the first course.

RESULTS

The response rate for the Japanese patients and the patients in the United States was 36.4% (95% CI, 22.4% to 52.2%) and 34.1% (95% CI, 20.5% to 49.9%), respectively. The only major toxicity was diarrhea, and other toxicities were mild in both populations. The incidence of grade 3 or higher diarrhea in the Japanese and Americans was 9% and 22%, respectively. Although the area under the curve and maximum concentration of fluorouracil were found to be slightly higher in the Japanese patients than the patients in the United States, and area under the curve-adjusted body surface area appeared to be comparable between the two groups.

CONCLUSION

The efficacy and pharmacokinetic parameters of UFT and LV are comparable in Japanese and American patients; however, a difference in toxicity profile, specifically diarrhea, was noted. This oral regimen of UFT and LV is considered to have similar activity against metastatic colorectal cancer and to have acceptable toxicity in patients in both countries.

Oral capecitabine vs intravenous 5-fluorouracil and leucovorin: integrated efficacy data and novel analyses from two large, randomised, phase III trials

This study evaluates the efficacy of capecitabine using data from a large, well-characterised population of patients with metastatic colorectal cancer (mCRC) treated in two identically designed phase III studies. A total of 1207 patients with previously untreated mCRC were randomised to either oral capecitabine (1250 mg m⁻² twice daily, days 1−14 every 21 days; n=603) or intravenous (i.v.) bolus 5-fluorouracil/leucovorin (5-FU/LV; Mayo Clinic regimen; n=604). Capecitabine demonstrated a statistically significant superior response rate compared with 5-FU/LV (26 vs 17%; P<0.0002). Subgroup analysis demonstrated that capecitabine consistently resulted in superior response rates (P<0.05), even in patient subgroups with poor prognostic indicators. The median time to response and duration of response were similar and time to progression (TTP) was equivalent in the two arms (hazard ratio (HR) 0.997, 95% confidence interval (CI) 0.885–1.123, P=0.95; median 4.6 vs 4.7 months with capecitabine and 5-FU/LV, respectively). Multivariate Cox regression analysis identified younger age, liver metastases, multiple metastases and poor Karnofsky Performance Status as independent prognostic indicators for poor TTP. Overall survival was equivalent in the two arms (HR 0.95, 95% CI 0.84–1.06, P=0.48; median 12.9 vs 12.8 months, respectively). Capecitabine results in superior response rate, equivalent TTP and overall survival, an improved safety profile and improved convenience compared with i.v. 5-FU/LV as first-line treatment for MCRC. For patients in whom fluoropyrimidine monotherapy is indicated, capecitabine should be strongly considered. Following encouraging results from phase I and II trials, randomised trials are evaluating capecitabine in combination with irinotecan, oxaliplatin and radiotherapy. Capecitabine is a suitable replacement for i.v. 5-FU as the backbone of colorectal cancer therapy.

The evolution of fluoropyrimidine therapy: from intravenous to oral

Chemotherapy for advanced colorectal cancer is based on i.v. 5-fluorouracil (5-FU). Numerous attempts have been made to increase the therapeutic benefit of 5-FU through schedule modification and biomodulation, but only modest improvements have been achieved. Capecitabine is an oral fluoropyrimidine that was developed in response to the clinical need for new therapeutic options offering improved efficacy, tolerability, and convenience for patients. Capecitabine was rationally designed to mimic continuous infusion 5-FU. It is rapidly and almost completely absorbed through the gastrointestinal wall and is converted to 5-FU via a three-step enzymatic cascade. 5-FU is generated preferentially in tumor by exploiting the higher activity of thymidine phosphorylase in tumor tissue compared with normal tissue. Results of a randomized, phase II trial led to the selection of a regimen of capecitabine for further clinical development (1,250 mg/m(2) twice daily for 14 days followed by a 7-day rest period). Subsequently, two large, randomized, phase III trials were conducted to compare capecitabine with i.v. bolus 5-FU/leucovorin ([LV]; Mayo Clinic regimen) in patients with metastatic colorectal cancer. A prospective, integrated analysis of data from the studies showed that capecitabine offers superior activity and an improved safety profile compared with 5-FU/LV. This article summarizes these developments in the treatment of colorectal cancer and assesses the feasibility of replacing i.v. 5-FU-based therapy with oral capecitabine. In addition, retrospective analyses assessing the impact of the dose modification scheme on the efficacy and tolerability of capecitabine are presented, and dose recommendations in special populations are reviewed.