Patient preferences for oral versus intravenous palliative chemotherapy

Capecitabine: a novel agent for the treatment of solid tumors

Although 5-fluorouracil (5-FU) has been used to treat breast and colorectal cancers for several decades, bolus 5-FU has disappointing efficacy. Prolonged infusion schedules and biomodulation with leucovorin have resulted in improved response rates, but these have not translated into significant improvements in survival in patients with metastatic disease. Furthermore, prolonged infusion is inconvenient for patients and can result in medical complications. New oral fluoropyrimidines, including capecitabine, are promising alternatives to i.v. 5-FU. Capecitabine generates 5-FU preferentially within tumors through exploitation of the high intratumoral activity of thymidine phosphorylase. The tumor selectivity of capecitabine has been confirmed in a clinical study of colorectal cancer patients. Clinical trials have shown that capecitabine is an effective, well-tolerated treatment for breast and colorectal cancer, with response rates of 20-26% in anthracycline- and taxane-pretreated metastatic breast cancer. As first-line monotherapy, capecitabine produces response rates of 25-27% in metastatic colorectal cancer and 30% in metastatic breast cancer. In all studies to date, capecitabine has been well tolerated, with adverse events typical of infusional 5-FU and manageable with treatment interruption/dose modification. Myelosuppression and alopecia are rare. Capecitabine is also being investigated in other solid tumors (including ovarian, pancreatic and gastric cancers) as adjuvant monotherapy in breast and colorectal cancer, and in combination with other cytotoxic agents. Results of ongoing trials are eagerly awaited.

Randomized, open-label, phase II trial of oral capecitabine (Xeloda) vs. a reference arm of intravenous CMF (cyclophosphamide, methotrexate and 5-fluorouracil) as first-line therapy for advanced/metastatic breast cancer

BACKGROUND

Oral capecitabine was evaluated in terms of overall response rate, safety, and tolerability as first-line therapy in women aged > or = 55 years with advanced/metastatic breast cancer.

PATIENTS AND METHODS

Ninety-five patients were randomized (2:1) to either intermittent oral capecitabine 1,255 mg/m2 twice daily (two weeks' treatment followed by a one-week rest period) or intravenous CMF (cyclophosphamide. methotrexate, 5-fluorouracil [5-FU]) administered every three weeks.

RESULTS

The overall response rate in the capecitabine group was 30% (95% confidence interval (95% CI): 19%-43%), including three complete responses (5%). The response rate observed in the CMF group was 16% (95% CI: 5%-33%), with no complete responses. Median time to disease progression was 4.1 months with capecitabine and 3.0 months with CME. Survival was similar in the two treatment groups (median 19.6 months with capecitabine. 17.2 months with CMF). The safety profiles were different for capecitabine and CMF. However, both regimens were generally well tolerated and treatment interruption and/or dose modification was effective in managing toxicities associated with capecitabine. Alopecia and myelosuppression were rare in patients receiving capecitabine while diarrhea and hand-foot syndrome were more common. Treatment interruption and/or individual dose adjustment of capecitabine was required in 34% of patients and was generally effective in managing adverse events. Treatment was stopped owing to toxicity in 16% of patients in the capecitabine arm. The incidence of deaths during or within 28 days of stopping study treatment was 8% and 6% in the capecitabine and CMF arms, respectively.

CONCLUSIONS

An oral, twice-daily regimen of capecitabine is effective and well tolerated when used as first-line chemotherapy in older patients (> or = 55 years) with advanced/metastatic breast cancer, and is suitable for outpatient therapy.

New options for outpatient chemotherapy--the role of oral fluoropyrimidines

For several decades fluoropyrimidines, especially 5-fluorouracil (5-FU), have played a role in standard chemotherapy regimens for a range of solid tumours, including breast and colorectal cancers. In recent years, schedule modification and biomodulation have achieved improved efficacy and tolerability. However, the complications arising from infused intravenous administration are well-recognized and there is an unmet medical need for oral agents with improved efficacy and tolerability, offering more convenient outpatient therapy. Several oral fluoropyrimidines are in development, including capecitabine, UFT (uracil plus tegafur), S-1 and eniluracil. As yet, only UFT/leucovorin and capecitabine have been evaluated in randomized phase III clinical trials in metastatic colorectal cancer. Both have demonstrated safety benefits and equivalent survival compared with the Mayo Clinic regimen, and capecitabine has demonstrated a significantly superior response rate. Time to disease progression was equivalent to the Mayo Clinic regimen with capecitabine, but inferior with UFT/leucovorin. Capecitabine is also effective in patients with taxoid-pretreated metastatic breast cancer, a population which previously had no established treatment options. Both capecitabine and UFT/leucovorin are being evaluated in combination with irinotecan and oxaliplatin in colorectal cancer, and vinorelbine and docetaxel/paclitaxel in breast cancer. In the future, these more convenient, oral fluoropyrimidines may replace intravenous 5-FU in the treatment of breast and colorectal cancer.

Oral fluoropyrimidine treatment of colorectal cancer

5-Fluorouracil (5-FU) has been utilized as part of standard chemotherapy for treatment of early-stage and metastatic colorectal cancer for more than 4 decades. The oral fluoropyrimidines have been studied extensively as an alternative to intravenous 5-FU. The goal of such an approach is to simplify drug administration and to improve the toxicity profile while maintaining efficacy that is at least equivalent to intravenous therapy. The goal of this article is to review the features of the main oral 5-FU prodrugs, which include capecitabine, uracil and tegafur (UFT)/leucovorin, S-1, and BOF-A2 and to describe their potential efficacy in treating colorectal cancer.

An Australian experience with temozolomide for the treatment of recurrent high grade gliomas

Temozolomide has an evolving role in the treatment of high grade gliomas. Recent studies suggest that temozolomide is well tolerated and efficacious. This study retrospectively analysed the activity and toxicity associated with temozolomide at two Australian centres over a 24 month period. Fifty-six patients with recurrent high grade gliomas were treated with temozolomide. Patients received temozolomide orally at 150-200mg/m(2)daily, days 1-5, every 4 weeks. The median number of treatment cycles was 4 (1-12). Of the 56 patients, 15 (27%) achieved complete or partial response and 18 (32%) achieved minor response or stable disease. There were no episodes of febrile neutropenia and temozolomide was generally well tolerated. In conclusion, temozolomide is an active therapy in patients with recurrent high grade glioma and our results concord with published studies.

Oral fluoropyrimidines among the new drugs for patients with metastatic breast cancer

Although drugs such as the taxoids and vinorelbine have increased the options available for anthracycline-resistant metastatic breast cancer, new therapeutic options are needed, particularly for taxoid-refractory tumours. Increasing emphasis is being placed on the development of oral agents, which many patients prefer provided efficacy is not compromised, particularly if the oral agents are less toxic than current intravenous agents. Capecitabine, a new, oral fluoropyrimidine, mimics continuous infusion 5-FU and is activated preferentially at the tumour site. Phase II studies of capecitabine have demonstrated encouraging response rates in patients with few further treatment options (20% response with an additional 43% achieving stable disease in paclitaxel-refractory patients; 36% response with a further 23% achieving stable disease in anthracycline-refractory patients). In addition, a randomized, phase II trial demonstrated a response rate of 30% (95% Cl: 19-43%) with capecitabine as first-line treatment for metastatic breast cancer, compared with 16% (95% Cl: 5-33%) in patients receiving low-dose CMF. These trials also showed that capecitabine has a favourable safety profile typical of infused fluoropyrimidines. Both alopecia and myelosuppression were rare. Capecitabine may therefore provide an effective, well-tolerated and convenient alternative to intravenous cytotoxic agents, not only in taxoid-resistant patients, but also in anthracycline-resistant metastatic breast cancer or as first-line therapy. Furthermore, the low incidence of myelosuppression makes capecitabine an attractive agent for incorporation into combination regimens with agents such as epirubicin/doxorubicin, the taxoids and vinorelbine.

Preoperative chemoradiotherapy with oral doxifluridine plus low-dose oral leucovorin in unresectable primary rectal cancer

PURPOSE

The use of oral chemotherapeutic agents in chemoradiotherapy provides several advantages. Doxifluridine, an oral 5-FU prodrug, has been shown to be effective in colorectal cancer. We attempted a Phase II trial of preoperative chemoradiotherapy with doxifluridine plus a low-dose oral leucovorin in unresectable primary rectal cancer patients. In this study, toxicity and efficacy were evaluated.

METHODS AND MATERIALS

There were 23 patients with primary unresectable rectal cancer in this trial, 21 of whom were available for analysis. The patients were treated with oral doxifluridine (900 mg/day) plus oral leucovorin (30 mg/day) from days 1 to 35, and pelvic radiation of 45 Gy over 5 weeks. Surgical resection was performed 5-6 weeks after the treatment.

RESULTS

Acute toxicity involved thrombocytopenia, nausea/vomiting, diarrhea, and skin reaction. All were in Grade 1/2, except diarrhea, which was not only the most frequent (7 patients, 33.3%), but also the only toxicity of Grade 3 (2 patients). The clinical tumor response was shown in 5 patients (23.8%) as a complete response and 13 patients (61.9%) as a partial response. A complete resection with negative resection margin was done in 18 patients (85.7%), in 2 of whom a pathologic complete response was shown (9.5%). The overall downstaging rate in the T- and N-stage groupings was 71.4% (15 patients).

CONCLUSION

This study demonstrated the efficacy and low toxicity of chemoradiotherapy with doxifluridine. Currently, a Phase III randomized trial of chemoradiotherapy is ongoing at our institute to compare the therapeutic efficacy of oral 5-FU with respect to i.v. 5-FU in locally advanced and unresectable rectal cancer.

Oral delivery of taxanes

Oral treatment with cytotoxic agents is to be preferred as this administration route is convenient to patients, reduces administration costs and facilitates the use of more chronic treatment regimens. For the taxanes paclitaxel and docetaxel, however, low oral bioavailability has limited development of treatment by the oral route. Preclinical studies with mdr1a P-glycoprotein knock-out mice, which lack functional P-glycoprotein activity in the gut, have shown significant bioavailability of orally administered paclitaxel. Additional studies in wild-type mice revealed good bioavailability after oral administration when paclitaxel was combined with P-glycoprotein blockers such as cyclosporin A or the structurally related compound SDZ PSC 833. Based on the extensive preclinical research, the feasibility of oral administration of paclitaxel and docetaxel in cancer patients was recently demonstrated in our Institute. Co-administration of cyclosporin A strongly enhanced the oral bioavailability of both paclitaxel and docetaxel. For docetaxel in combination with cyclosporin A an oral bioavailability of 90% was achieved with an interpatient variability similar to that after intravenous drug administration; for paclitaxel the oral bioavailability is estimated at approximately 50%. The safety of the oral route for both taxanes is good. A phase II study of weekly oral docetaxel in combination with cyclosporin A is currently ongoing.

Integrating the oral fluoropyrimidines into the management of advanced colorectal cancer

In colorectal cancer, leucovorin-modulated 5-fluorouracil (5-FU) has been the mainstay of both adjuvant treatment and treatment of metastatic disease for many years. In advanced disease, response rates of 10-43% are reported; efforts to improve efficacy through schedule modification, including prolonged infusions, have led to limited success. New agents with improved efficacy, tolerability and ease of administration are required. Among the newer drugs, irinotecan and oxaliplatin are becoming established as first- and second-line treatment for advanced disease. Their novel mechanisms of action have proven to be of value in 5-FU-resistant patients. In tandem with these developments, thymidylate synthase inhibition has remained an important objective and oral fluoropyrimidines such as capecitabine and UFT (uracil plus tegafur)/leucovorin have been developed with this goal in mind. Two large, phase III studies of capecitabine in metastatic disease demonstrated objective response rates of 26.6 and 24.8%. UFT/leucovorin has also been evaluated in phase III trials, with an 11.7% response rate reported. Both agents are being evaluated in combination with oxaliplatin and irinotecan, and ultimately oral fluoropyrimidines as monotherapy or combination therapy may replace intravenous (i.v.) 5-FU as first-line treatment for metastatic colorectal cancer.

Comparison of oral capecitabine versus intravenous fluorouracil plus leucovorin as first-line treatment in 605 patients with metastatic colorectal cancer: results of a randomized phase III study

PURPOSE

To compare the response rate, efficacy parameters, and toxicity profile of oral capecitabine with bolus intravenous (IV) fluorouracil plus leucovorin (5-FU/LV) as first-line treatment in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

We prospectively randomized 605 patients to treatment with oral capecitabine for 14 days every 3 weeks or 5-FU/LV by rapid IV injection daily for 5 days in 4-week cycles.

RESULTS

The overall objective tumor response rate among all randomized patients was significantly higher in the capecitabine group (24.8%) than in the 5-FU/LV group (15.5%; P =.005). In the capecitabine and 5-FU/LV groups, median times to disease progression were 4.3 and 4.7 months (log-rank P =.72), median times to treatment failure were 4.1 and 3.1 months (P =.19), and median overall survival times were 12.5 and 13.3 months (P =.974), respectively. Capecitabine, compared with bolus 5-FU/LV treatment, produced a significantly lower incidence (P <.0002) of diarrhea, stomatitis, nausea, and alopecia. Patients treated with capecitabine also displayed lower incidences of grade 3/4 stomatitis and grade 3/4 neutropenia (P <.0001) leading to significantly less neutropenic fever/sepsis. Grade 3 hand-foot syndrome (P <.00001) and grade 3/4 hyperbilirubinemia were the only toxicities more frequently associated with capecitabine than with 5-FU/LV treatment.

CONCLUSION

Oral capecitabine was more active than 5-FU/LV in the induction of objective tumor responses. Time to disease progression and survival were at least equivalent for capecitabine compared with the 5-FU/LV arm. Capecitabine also demonstrated clinically meaningful benefits over bolus 5-FU/LV in terms of tolerability.

The role of capecitabine, an oral, enzymatically activated fluoropyrimidine, in the treatment of metastatic breast cancer

Capecitabine is an oral fluoropyrimidine that mimics continuous infusion 5-fluorouracil and generates 5-fluorouracil preferentially at the tumor site. It is activated via a three-step enzymatic pathway, the final step of which requires thymidine phosphorylase, an enzyme that is significantly more active in tumor than normal tissue. As an oral agent, capecitabine is more convenient for patients and medical personnel, and avoids the complications associated with venous access. This paper reviews the development and clinical experience of capecitabine in breast cancer treatment. Clinical trials have established the efficacy and tolerability of capecitabine in anthracycline- and taxane-pretreated metastatic breast cancer, showing that capecitabine is an effective therapy for patients who have exhausted all established treatment options. Moreover, randomized, phase II studies have demonstrated that capecitabine is effective in anthracycline-pretreated patients and as first-line therapy for metastatic breast cancer. In addition to its confirmed efficacy, the favorable safety profile of capecitabine, particularly the low myelosuppression rate, makes it an attractive agent for incorporation into combination regimens. Therefore numerous trials have assessed the feasibility of capecitabine-containing regimens, and have shown promising results. Capecitabine is an important new treatment option for breast cancer patients, and ongoing clinical trials should further define its role in a range of settings.

Phase II study of oral eniluracil, 5-fluorouracil, and leucovorin in patients with advanced colorectal carcinoma

BACKGROUND

The oral administration of 5-fluorouracil (5-FU) is hindered by erratic bioavailability due to catabolism of 5-FU by the enzyme dihydropyrimidine dehydrogenase (DPD) in the gastrointestinal tract. Eniluracil is a potent inactivator of DPD which results in 100% oral bioavailability of 5-FU. Leucovorin (LV) is another biochemical modulator of 5-FU that potentiates inhibition of thymidylate synthase, the primary target of 5-FU. The goal of this study was to determine the antitumor activity and toxicity of an oral regimen containing eniluracil, 5-FU, and LV in patients with colorectal carcinoma.

METHODS

Sixty eligible patients who had previously untreated, measurable, metastatic colorectal carcinoma were treated with oral eniluracil 50 mg on Days 1-7, 5-FU 20 mg/m(2) on Days 2-6, and LV 50 mg on Days 2-6. Cycles were repeated at 28-day intervals.

RESULTS

The overall response rate was 13% (95% confidence interval [CI] = 6, 25%), with 1 complete response and 7 partial responses. Three additional patients had partial responses that were not confirmed at subsequent evaluations. The median time to progression of disease was 4.4 months (95% CI = 3.45, 7.69) and the median survival time was 12.6 months (95% CI = 9.1, 14.75). Grade 3-5 toxicity (1 toxic death) occurred in 51 patients (85%). Grade 4 neutropenia occurred in 25 patients (42%), and 18 patients (30%) had Grade 3-4 diarrhea. Twenty-one patients (35%) were hospitalized for toxicity, and 12 (20%) had febrile neutropenia. Baseline creatinine clearance was associated inversely with severe toxicity (P = 0.001).

CONCLUSIONS

Although antitumor activity was observed, the frequent occurrence of severe toxicity with this regimen limited its clinical utility. Alternate schedules with a more favorable therapeutic index are undergoing clinical testing and should be pursued. The high level of toxicity observed with orally administered low dose 5-FU underscored the potency of eniluracil as a biochemical modulator.

The pursuit of optimal outcomes in cancer therapy in a new age of rationally designed target-based anticancer agents

There have been extraordinary advances in anticancer therapy over the last few decades, particularly for patients with relatively uncommon malignancies, largely because of the advent of nonspecific cytotoxic chemotherapeutics. Although these agents have also brought improved outcomes for patients with many of the more common solid cancers, it is clear that the point of 'diminishing return' has been reached. The recent development of a plethora of rationally designed target-based anticancer agents has opened up new opportunities and extraordinary therapeutic challenges. Since these agents appear primarily to target malignant cells, they can be expected to be less toxic at clinically effective doses than the cytotoxic agents. Among the various types of rationally designed target-based agents are those that target strategic facets of cell growth signal transduction, angiogenesis, metastasis and cell cycle regulation. While the primary therapeutic benefit of these agents is expected to be decreased tumour growth, evidence suggests that objective tumour responses may also be achieved. However, because of their potentially cytostatic properties, the clinical efficacy of such biologically based agents may not be readily demonstrable with traditional phase I and II study methodologies. Additionally, their dose-toxicity relationships are likely to be less steep than those of the nonspecific cytotoxic agents, thereby rendering such concepts as the maximum tolerated dose less meaningful than alternatives such as the optimal biological dose or the biologically effective dose. Those end-points generally considered, both from a regulatory and clinical viewpoint, to be of secondary importance in trials of cytotoxic agents, such as time to disease progression, disease-related symptoms and quality of life, may evolve into primary end-points. Present findings from preclinical studies suggest that the development, evaluation and general clinical use of rationally designed target-based anticancer agents will require a radical departure from the traditional paradigms if the full potential of these new therapies is to be exploited.

Capecitabine (Xeloda) improves medical resource use compared with 5-fluorouracil plus leucovorin in a phase III trial conducted in patients with advanced colorectal carcinoma

Standard therapy for advanced or metastatic colorectal cancer consists of 5-fluorouracil plus leucovorin (5-FU/LV) administered intravenously (i.v.). Capecitabine (Xeloda), an oral fluoropyrimidine carbamate which is preferentially activated by thymidine phosphorylase in tumour cells, mimics continuous 5-FU and is a recently developed alternative to i.v. 5-FU/LV. The choice of oral rather than intravenous treatment may affect medical resource use because the two regimens do not require the same intensity of medical intervention for drug administration, and have different toxicity profiles. Here we examine medical resource use in the first-line treatment of colorectal cancer patients with capecitabine compared with those receiving the Mayo Clinic regimen of 5-FU/LV. In a prospective, randomised phase III clinical trial, 602 patients with advanced or metastatic colorectal cancer recruited from 59 centres worldwide were randomised to treatment with either capecitabine or the Mayo regimen of 5-FU/LV. In addition to clinical efficacy and safety endpoints, data were collected on hospital visits required for drug administration, hospital admissions, and drugs and unscheduled consultations with physicians required for the treatment of adverse events. Capecitabine treatment in comparison to 5-FU/LV in advanced colorectal carcinoma resulted in superior response rates (26.6% versus 17.9%, P=0.013) and improved safety including less stomatitis and myelosuppression. Capecitabine patients required substantially fewer hospital visits for drug administration than 5-FU/LV patients. Medical resource use analysis showed that patients treated with capecitabine spent fewer days in hospital for the management of treatment related adverse events than did patients treated with 5-FU/LV. In addition, capecitabine reduced the requirement for expensive drugs, in particular antimicrobials fluconazole and 5-HT3-antagonists to manage adverse events. As anticipated with an oral home-based therapy patients receiving capecitabine needed more frequent unscheduled home, day care, office and telephone consultations with physicians. In the light of clinical results from the phase III trial demonstrating increased efficacy in terms of response rate, equivalent time to progression (TTP) and survival (OS), and a superior safety profile, the results from this medical resource assessment indicate that capecitabine treatment of colorectal cancer patients results in a substantial resource use saving relative to the Mayo Clinic regimen of 5-FU/LV. This benefit is derived principally from the avoidance of hospital visits for i.v. drug administration, less expensive drug therapy for the treatment of toxic side-effects, and fewer treatment-related hospitalisations required during the course of therapy for adverse drug reactions in comparison to patients treated with 5-FU/LV.

Use of bisphosphonates in skeletal metastasis

At present, there is sufficient evidence to propose practice guidelines that would include the use of bisphosphonates in the management of hypercalcemia, in breast cancer with bone metastases and multiple myeloma. Future research should concentrate on investigating the adjuvant use of bisphosphonates in breast cancer, particularly in order to find out the adequate target groups. Phase III studies comparing the old and new generation bisphosphonates are important as well as trials comparing the other palliative regimens with bisphosphonates. A widespread use of bisphosphonates would have a major impact on drug budgets. Does the cost of achieved palliation represent the optimal use of resources when compared with other possible options for palliation? This issue has not become easier with the emerging new expensive regimens in oncology. An economical analysis, ideally in the setting of randomized trials, is needed.

Coadministration of cyclosporine strongly enhances the oral bioavailability of docetaxel

PURPOSE

Oral bioavailability of docetaxel is very low, which is, at least in part, due to its affinity for the intestinal drug efflux pump P-glycoprotein (P-gp). In addition, metabolism of docetaxel by cytochrome P450 (CYP) 3A4 in gut and liver may also contribute. The purpose of this study was to enhance the systemic exposure to oral docetaxel on coadministration of cyclosporine (CsA), an efficacious inhibitor of P-gp and substrate for CYP 3A4.

PATIENTS AND METHODS

A proof-of-concept study was carried out in 14 patients with solid tumors. Patients received one course of oral docetaxel 75 mg/m(2) with or without a single oral dose of CsA 15 mg/kg. CsA preceded oral docetaxel by 30 minutes. During subsequent courses, patients received intravenous (IV) docetaxel 100 mg/m(2).

RESULTS

The mean (+/- SD) area under the concentration-time curve (AUC) in patients who received oral docetaxel 75 mg/m(2) without CsA was 0.37 +/- 0.33 mg.h/L and 2.71 +/- 1.81 mg.h/L for the same oral docetaxel dose with CsA. The mean AUC of IV docetaxel 100 mg/m(2) was 4.41 +/- 2.10 mg.h/L. The absolute bioavailability of oral docetaxel was 8% +/- 6% without and 90% +/- 44% with CsA. The oral combination of docetaxel and CsA was well tolerated.

CONCLUSION

Coadministration of oral CsA strongly enhanced the oral bioavailability of docetaxel. Interpatient variability in the systemic exposure after oral drug administration was of the same order as after IV administration. These data are promising and form the basis for the further development of a clinically useful oral formulation of docetaxel.

The homocamptothecin BN 80915 is a highly potent orally active topoisomerase I poison

BN 80915, a lead compound of the homocamptothecin (hCPT) family, has entered clinical trials. BN 80915 is a difluoro-hCPT where the six-membered alpha-hydroxylactone ring of camptothecin (CPT) is replaced by a seven-membered beta-hydroxylactone ring. Preclinical data reported here show that in spite of the modification to the crucial E-ring of CPTs, BN 80915 retains topoisomerase I poisoning activity as shown in living HT29 cells as well as in cell-free assays, where BN 80915 always performs better than SN-38 or TPT. In antiproliferative assays BN 80915 is also very potent as evidenced by IC50s values consistently lower than those of SN38 in sensitive cell lines as well as in their related multidrug-resistant lines overexpressing P-glycoprotein or multidrug resistance-associated protein. Furthermore, in human plasma, in contrast to CPT analogs, the hydrolysis of BN 80915 is slow, leading to improved plasma stability, and irreversible, thus avoiding toxicity related to the accumulation of active principle during excretion in the urinary tract. These findings may account for the good in vivo efficacy observed in PC3 xenograft experiments where BN 80915 administered orally at very low doses doubled the tumor growth delay in comparison to CPT-11 administered i.p. Altogether, these results strongly support further development of BN 80915.

Phase I study of preoperative oral uracil and tegafur plus leucovorin and radiation therapy in rectal cancer

PURPOSE

Preoperative combined-modality therapy for rectal cancer may allow for sphincter preservation, while decreasing recurrence rates and improving the overall prognosis. Oral chemotherapy with uracil and tegafur (UFT) plus leucovorin (LV) may reduce costs and complications associated with protracted infusions of fluorouracil. Our goal was to evaluate the safety of UFT plus LV combined with preoperative radiation and determine the maximum-tolerated dose (MTD) and dose-limiting toxicity (DLT) of UFT plus LV in this setting.

PATIENTS AND METHODS

Patients with tumor-node-metastasis stage II or III rectal cancer received escalating doses of UFT (starting at 250mg/m(2)/d, with 50-mg/m(2)/d increments between consecutive cohorts) and fixed doses of LV (90 mg/d). The UFT and LV combination was given 5 days per week concurrently with a 5-week course of preoperative radiation totaling 45 Gy (1.8 Gy/fraction). Surgery was performed 4 to 6 weeks after radiation and was followed by four 35-day cycles of fixed doses of UFT and LV (28 days of therapy each cycle).

RESULTS

Fifteen patients were treated, and 13 received the full preoperative chemotherapy. All planned radiation was delivered successfully. The MTD of UFT with radiation was 350 mg/m(2)/d with 90 mg/d of LV. Diarrhea was the DLT. Sphincter-preserving surgery was performed in 12 of 14 patients. One patient had progressive disease before surgery. Pathologic evaluation of 14 resected specimens showed a complete response in three cases.

CONCLUSION

Preoperative chemoradiation with oral UFT plus LV is feasible and well tolerated and should be further investigated.

The oral route for the administration of cytotoxic drugs: strategies to increase the efficiency and consistency of drug delivery

There is an increasing interest to administer cytotoxic drugs to patients by the oral route. Quality of life issues, treatment advantages and pharmaco-economics are major arguments in favor of oral therapy. However, low or moderate bioavailability in combination with considerable interpatient variability are frequently observed which may reduce the feasibility of the oral route for this class of drugs with a generally narrow therapeutic window. Until recently, investigators focused on absorption enhancers which slightly damage the intestinal surface such as salicylates, methylxanthines and surfactants to improve the oral bioavailability of drugs. To date, a shift can be seen towards more subtle mechanisms to enhance the absorption. This review article focuses on two important mechanisms that determine the oral bioavailability of cytotoxic drugs. These include the presence of drug transporters in the intestinal epithelium pumping drugs into the intestinal lumen, such as MDR1 type P-glycoproteins, and first-pass elimination by cytochrome P450 isoenzymes (e.g. 3A4 and 3A5) or other enzymes in the intestines and/or liver. Currently preclinical and clinical studies are being performed to explore the feasibility of blocking these transporters/enzymes in order to achieve higher and less variable systemic drug levels after oral dosing. This review gives an update of the results of these studies. It is concluded however, that further research to unravel the processes involved in oral drug uptake is warranted to make the oral route a more efficient and consistent way of drug administration.

Phase I clinical and pharmacokinetic study of oral S-1 in patients with advanced solid tumors

PURPOSE

To investigate the side effects, determine the maximum-tolerated dose (MTD), and study the pharmacokinetics of S-1, an oral fluoropyrimidine-based antineoplastic agent consisting of the fluorouracil (5-FU) prodrug tegafur combined with two modulators, 5-chloro-2,4-dihydroxypyridine and potassium oxonate.

PATIENTS AND METHODS

Patients with advanced solid tumors received S-1 bid for 28 days, followed by 1 week of rest. 5-FU pharmacokinetics were investigated after a single initial dose of S-1 during the first 24 hours and weekly thereafter.

RESULTS

Twenty-eight patients received S-1 at the four consecutive dose levels of 25, 45, 35, and 40 mg/m(2). The MTD was initially found at 45 mg/m(2), with diarrhea as the dose-limiting toxicity (DLT). Diarrhea was also the DLT at the dose of 40 mg/m(2), which was the MTD for patients exposed to extensive prior chemotherapy. Other toxicities were generally mild. Two patients had a reduction of more than 50% in tumor dimension. Plasma pharmacokinetics of 5-FU were linear; at the highest S-1 dose level, 5-FU plasma peak concentrations reached 1 to 2 micromol/L, and the half-life of 5-FU was 3 to 4 hours. A statistically significant relationship was observed between the severity of diarrhea and pharmacokinetic parameters of 5-FU.

CONCLUSION

The recommended dose of S-1 in chemotherapy-naive or minimally chemotherapy-exposed patients is 40 mg/m(2) bid on 28 consecutive days, every 5 weeks. In heavily pretreated patients, the recommended dose is 35 mg/m(2) bid. Phase II trials are warranted in tumors known to be responsive to 5-FU treatment.

Eniluracil: an irreversible inhibitor of dihydropyrimidine dehydrogenase

One of the most widely used drugs in cancer chemotherapy is 5-fluorouracil (5-FU). 5-FU is optimally delivered via continuous iv. infusion, which is both cumbersome and expensive. Prolonged oral dosing of 5-FU could mimic continuous infusion with less inconvenience and cost. However, oral administration of 5-FU has been hampered by incomplete and erratic bioavailability due to substantial variability in the activity of dihydropyrimidine dehydrogenase (DPD), the rate-limiting enzyme in 5-FU catabolism. Eniluracil (ethynyluracil, GlaxoWellcome, USA), a uracil analogue, which irreversibly inhibits DPD, increases the oral bioavailability of 5-FU to 100%, facilitating uniform absorption and predictable toxicity. Cytotoxicity is enhanced one- to five-fold in cell lines treated with eniluracil plus 5-FU compared with 5-FU alone. Though eniluracil is neither toxic nor active as a single agent in animals, it improves the antitumour efficacy and therapeutic index of 5-FU. In Phase I trials, eniluracil markedly reduced the maximum tolerated dose of oral 5-FU, increased the half-life 20-fold and decreased the clearance 22-fold. DPD is completely inactivated within 1 h of eniluracil administration. Two dosing schedules have been evaluated in combination with oral 5-FU: a 5-day schedule every 28 days and a 28-day schedule every 35 days. The dose-limiting toxicity on the first schedule is myelosuppression with diarrhoea being dose-limiting on the 28-day schedule. Phase II trials employing the 28-day schedule have been completed in cancers of the colon, breast, liver and pancreas. Phase III trials in colorectal and pancreatic carcinoma have been completed and await analysis. Eniluracil is a promising drug, which permits reliable and safe administration of oral 5-FU and has the potential to overcome 5-FU resistance mediated by overexpression of DPD.

Phase II study of S-1, a novel oral fluorophyrimidine derivative, in patients with metastatic colorectal carcinoma. S-1 Cooperative Colorectal Carcinoma Study Group

This study set out to evaluate, in patients with metastatic colorectal carcinoma, the efficacy and toxicity of S-1, which contains tegafur, 5-chloro-2,4-dihydroxypyridine (CDHP) and potassium oxonate, based on a biochemical modulation of 5-fluorouracil (5-FU) targeted at inhibition of dihydropyrimidine dehydrogenase (DPD). Sixty-three patients with measurable metastatic colorectal carcinoma were enrolled into the study. None of the patients had received prior chemotherapy except for adjuvant setting. S-1 was administered orally twice daily at a standard dose of 80 mg m(-2) day(-1) for 28 days followed by a 14-day rest. This agent is continued until disease progression, unaccepted toxicity, or patient refusal. Twenty-two (35%) of the 62 eligible patients achieved PR with a 95% confidence interval of 25-48%. Five of the 10 patients with a history of adjuvant chemotherapy achieved partial remission. The median survival time was 12 months. Major adverse reactions included myelosuppressive and gastrointestinal toxicities, though their incidence of grade 3 or 4 being 13% in neutropenia and less than 10% in the others. None of the 53 patients treated as outpatients required hospitalization due to adverse reactions: These results suggest that S-1 achieves similar responses to those of infusional 5-FU plus leucovorin and shows the potential of another biochemical modulation with easily manageable toxicity.

Oral chemotherapeutic agents for colorectal cancer

A number of novel oral chemotherapeutic agents are entering practice or are under development in the United States. Many of these agents display significant clinical activity against colorectal cancer. Many classes of compounds, including fluoropyrimidine analogs, dihydropyrimidine dehydrogenase (DPD) inhibitors, topoisomerase inhibitors, farnesyl transferase inhibitors, and others, are being developed for oral administration. This manuscript describes the progress of clinical development of these agents and also explores the relative merits and challenges of these approaches. Economic issues, patient preference, and patient selection issues surrounding oral chemotherapy for colorectal cancer will also be discussed.

Cost-effectiveness of 24 or 48 weeks of interferon alpha-2b alone or with ribavirin as initial treatment of chronic hepatitis C. International Hepatitis Interventional Therapy Group

OBJECTIVE

Initial therapy with ribavirin and interferon alpha-2b results in a higher sustained virological response than interferon alone, but this regimen is expensive. We aimed to examine the cost-effectiveness of 24- or 48-wk initial treatment with combination therapy versus interferon alone for patients who have chronic hepatitis C.

METHODS

Data from recent randomized clinical trials comparing combination therapy to interferon alone were applied to a previously published computer cohort simulation to project lifelong clinical and economic outcomes. Natural history and economic estimates were based on published literature, expert panel estimates, and actual variable cost and reimbursement data.

RESULTS

Using treatment stopping rules, sustained viral negative response rates would be 33.1% and 39.8% for patients receiving 24 versus 48 wk of ribavirin/interferon, compared with 14.3% for 48 wk of interferon alone. Compared to the interferon alone strategy, 24 or 48 wk of combination therapy should prolong life expectancy by 1.4 to 2.0 yr at marginal cost-effectiveness ratios of $4,400 to $5,400 per discounted quality-adjusted life-year (DQALY) gained. Compared to 24 wk of combination therapy, 48 wk of combination therapy should prolong life expectancy by 0.6 yr at a marginal cost-effectiveness ratio of $7,700 per DQALY gained. The results were robust, with 24 or 48 wk of combination therapy remaining preferred and cost-effective in sensitivity analysis compared with interferon alone.

CONCLUSION

For patients with chronic hepatitis C, 24 or 48 wk of ribavirin and interferon should prolong life and be cost-effective when compared with 48 wk, of interferon alone.

Oral topoisomerase 1 inhibitors in adult patients: present and future

The renewed interest in topoisomerase 1 inhibitors, based on new insights on the mechanism of action and the development of semi-synthetic derivates of camptothecin with a more favourable toxicity profile, has led to extensive preclinical and clinical research. Significant levels of anti-tumor activity in human tumor xenografts were seen especially with prolonged duration of exposure. Since oral drug delivery is a more convenient method for prolonged drug administration, and preferred by patients, further development of oral formulations seems attractive. Common concerns in the development of oral formulations are their sometimes low oral bioavailability and the frequently large intra- and interpatient variation in systemic exposure. Efforts to improve absorption and minimize intestinal metabolism/efflux of the oral chemotherapeutic agent using new formulas might lead to better bioavailability. Pharmacokinetic and pharmacodynamic evaluations have enabled guidance in recommendations of schedules. Given the interpatient variation in exposure it is interesting to note that flat dosing of topotecan resulted in the same systemic exposure compared with the more complex dosing per body surface area. In order to diminish the interpatient variation in exposure to 9-AC a limited sampling model for oral 9-AC was developed, enabling prediction of the systemic exposure for 9-AC and optimizing treatment for any given patient. Drug sequencing plays a key role in the combination topotecan/cisplatin and might be important for combination with other classes of drugs. Therefore, forthcoming phase 1 trials on combination therapy with oral topoisomerase 1 inhibitors should include studies on sequence dependence and pharmacokinetic analyses to evaluate any mutual interaction.

Clinical studies in the development of new anticancer agents exhibiting growth inhibition in models: facing the challenge of a proper study design

Various new specifically targeted anticancer agents such as matrixmetalloproteinase inhibitors, angiogenesis inhibitors, farnesyl transferase inhibitors, and tyrosine kinase inhibitors have been developed in recent years. These agents exert antitumor activity through specific target inhibition, and preclinical studies showed dose-dependent tumor growth inhibition and only sporadic tumor regressions. Toxicity of these new agents was often strikingly mild or did not occur at all. Clinical studies are now being performed. Because these new agents might have a different toxicity profile and exert their antitumor activity in a way that is completely different from that of cytotoxic agents, the design of clinical studies will have to be adapted in several ways, and new endpoints for phase I, II, and III studies must be defined.

A reappraisal of the role of chlorambucil in patients with end stage ovarian cancer who have previously been treated with platinum regimens

The role of chlorambucil in end stage platinum resistant epithelial ovarian cancer was evaluated in women with end stage ovarian cancer. They had received platinum based chemotherapy and all other intravenous chemotherapeutic options had been exhausted. Over a 15 year period, 30 patients were identified. The median age was 64.5 years (range 45-81). The median number of chlorambucil pulses was 4 (range 1-16). The median survival following the introduction of chlorambucil was 5.5 months (range 0.72-38.8). The 22 patients who survived for longer than three months were significantly younger than those who did not (p = 0.03). Apart from two patients who developed transient myelosupression there were no toxic side effects. Chlorambucil should be considered as a therapeutic option in end stage ovarian cancer. It is has minimal toxicity, and can be prescribed safely for long term use. In younger women, an increase in benefit may be anticipated.

Post hoc economic analysis of temozolomide versus dacarbazine in the treatment of advanced metastatic melanoma

PURPOSE

To determine the potential economic implications resulting from oral temozolomide (TEM) compared with intravenous (IV) dacarbazine (DTIC) for metastatic melanoma.

PATIENTS AND METHODS

We performed a cost-effectiveness (CE) analysis using hazard ratios (HRs) from the phase III (Schering I95-018) trial comparing TEM 200 mg/m(2)/d orally for 5 days every 28 days with DTIC 250 mg/m(2)/d IV for 5 days every 21 days. Sensitivity analyses assessed a range of TEM's efficacy and costs, direct nonmedical costs, and the DTIC schedule.

RESULTS

The trial found an overall survival trend favoring TEM; median survival times of patients treated with DTIC and TEM were 6.4 and 7.7 months, respectively (HR = 1.18; 95% confidence interval [CI], 0.92 to 1.52; intention to treat, P =.20). The mean increase in survival of TEM over DTIC was 1.1 months. The projected average costs per patient were greater with TEM than DTIC ($6,902 v $3,697, respectively). The incremental CE ratio using TEM was $36,990 per life-year or $101 per day of life gained. The CE ratio's 95% CI ranged from -$65,180 (DTIC is more effective) to $18, 670 per year of life gained. The CE ratios decreased 50% if direct nonmedical costs were included and increased 50% if DTIC's efficacy was unchanged if given as a single daily dosage. Sixty percent of simulations found TEM with a CE threshold of less than $50,000 per life-year gained.

CONCLUSION

Although the base-case efficacy of TEM compared with DTIC was not statistically significant, its associated incremental CE would be comparable with many interventions. TEM for metastatic melanoma illustrates the tension confronting providers choosing between similar agents that markedly differ in convenience and costs.

Cost effectiveness of ribavirin/interferon alfa-2b after interferon relapse in chronic hepatitis C

PURPOSE

Many patients with chronic hepatitis C who are treated with interferon suffer a relapse after an initial response. About half of these patients have a sustained virological response to retreatment with the combination of ribavirin and interferon alfa-2b. The aim of this study was to estimate the cost effectiveness of retreatment with combination therapy versus interferon alone for patients who have previously relapsed after interferon.

SUBJECTS AND METHODS

Data from a randomized trial among 345 relapsed patients that compared combination therapy with interferon alone were used to project lifelong clinical and economic outcomes. Natural history and economic estimates (discounted at 3% per year) were based upon published literature, expert panel estimates, and cost and reimbursement data.

RESULTS

Compared with retreatment with interferon alone, combination therapy should prolong life expectancy by about 2 discounted quality-adjusted life years (3 life years, undiscounted) while increasing costs modestly. The results were robust, maintaining an advantage to combination therapy in sensitivity analysis for all subgroups and with reasonable variations in all model parameters.

CONCLUSION

For patients with chronic hepatitis C who relapse after an initial response to interferon alone, retreatment with the combination of ribavirin and interferon alfa-2b should prolong life and be cost effective.

Patient participation in medical decision-making: a French study in adjuvant radio-chemotherapy for early breast cancer

BACKGROUND

Shared decision-making is increasingly advocated as an ideal model. However, very few studies have tested the feasibility of giving patients the opportunity to participate in the choice of treatment.

PATIENTS AND METHODS

Women, with non-metastatic breast cancer, eligible for non-intensified adjuvant chemotherapy attending our hospital were proposed two administrations of chemotherapy and radiotherapy: a sequential and a concomitant one. Two patient-questionnaires were used to elicit motivations for their choice and their degree of comfort with the process of decision-making and one questionnaire to test physicians' ability to predict patients' choice.

RESULTS

Participation rate in the study was 75.3% (n = 64). Majority (64%) of patients chose the concomitant treatment. Multivariate analysis revealed that patients with a lower level of education, who discussed the choice with social circle, and who most feared side-effects were more likely to choose the sequential treatment. Physicians were able to predict patients' choice in 66% of cases. 89% of patients declared that they were fully satisfied with having participated in the choice of treatment and 79% supported shared decision-making.

CONCLUSIONS

Results are in favour of promoting active participation of cancer-patients in medical decision-making. The adequate degree of such participation remains however to be elicited and tested for therapeutic choices implying more difficult trade-offs between quantity and quality of life.

Novel oral chemotherapy agents

The development of anticancer drugs has conventionally focused on intravenous rather than oral regimens. Recently, interest in oral administration of chemotherapy has been stimulated by the discovery of oral fluoropyrimidines, which appear to possess at least an equivalent efficacy and the potential to reduce toxicity compared with intravenous therapies. Using rational drug design, several oral fluoropyrimidines have been developed, including capecitabine, UFT (tegafur and uracil), eniluracil plus oral 5-fluorouracil (5-FU), and S-1. In addition to the oral fluoropyrimidines, other novel agents available for potential oral administration include irinotecan and temozolomide.

Idarubicin and cyclophosphamide--an active oral chemotherapy regimen for advanced breast cancer

Between October 1993 and September 1994, 33 women with metastatic breast cancer aged between 29 and 74 years with a median age of 58 were entered into a study of oral chemotherapy from three UK centres. Patients by definition had metastatic disease and were fit and well with performance status 0 or 1 in 23 cases, 2 in seven cases and 3 in two cases (one missing). Five patients had received prior adjuvant CMF chemotherapy, nine first line non-anthracycline containing chemotherapy for relapse, eight patients second line non-anthracycline containing chemotherapy and all patients had had hormone therapy either as adjuvant or for relapsed disease. Adjuvant radiotherapy had been given to 17 and palliative radiotherapy to 12 patients. In nine patients there was one site of disease at start of therapy, in 10 two sites, in 11 three sites and in three patients four or more sites. The regimen comprised oral idarubicin 15 mg/m2 on day 1, 10 mg/m2 on days 2 and 3 and oral cyclophosphamide 250 mg/m2 (maximum 400 mg) on days 1, 2 and 3. Treatment was continued until disease progression or toxicity.

RESULTS

Overall 25% of 32 evaluable patients responded objectively including one complete response; 50% of patients had stable disease and 25% of patients progression. Among patients who had had no prior chemotherapy the objective response rate was 37.5%; 45% of patients had symptomatic improvement. The most common severe toxicity was granulocytopenia WHO grade 3 or more in 69.7% of patients. Thrombocytopenia grade 3 or 4 was seen in four patients. Six patients had documented infections and all but four patients had alopecia. All patients complained of mild or moderate fatigue. Nausea and vomiting occurred in 75% of patients but only four individuals had grade 3 toxicity. Two patients stopped therapy after myocardial infarction and one after impaired cardiac function was noted. The median time to progression was 2.7 months (1-11.5 months) and median survival time 8.8 months (1-13+ months).

CONCLUSION

The combination chemotherapy is active in heavily treated patients with manageable toxicity but there are problems in heavily pre-treated patients. There was good compliance in taking medication and at the doses chosen the drugs appear to be suitable for younger fitter patients.

Cost analysis of second-line therapies for platinum-refractory ovarian cancer: reimbursement dilemmas for Medicare patients

Currently used options for salvage therapy for epithelial ovarian cancer include intravenously administered paclitaxel or topotecan and orally administered altretamine or etoposide. The response rates for these agents are similar (14-26%), whereas the type and incidence of adverse events differ. Under current legislation, Medicare will reimburse intravenous outpatient chemotherapy regimens only or oral regimens with a marketed intravenous formulation, despite that 89% of cancer patients prefer oral therapies. To compare the out-of-pocket costs and costs to the Medicare system, a cost minimization analysis of treatment with these agents was conducted using published phase II and phase III data. The total cost of treatment was $15,767 for paclitaxel, $18,635 for topotecan, $4477 for altretamine, and $5016 for etoposide. The out-of-pocket costs to the patient were $83, $37, $4477, and $6, respectively. Although a physician's first consideration in choosing a therapy is efficacy and toxicity, current Medicare reimbursement policies restrict patient options for cancer care. Because Medicare adopts managed care and health maintenance organizations into the management of patient care, cost effectiveness will likely become an important consideration in the treatment of cancer.

A patient preference study comparing raltitrexed ('Tomudex') and bolus or infusional 5-fluorouracil regimens in advanced colorectal cancer: influence of side-effects and administration attributes

Current chemotherapy regimens used in advanced colorectal cancer (ACRC) are similar in terms of efficacy, but differ importantly in terms of side-effects and administration profiles. These differences may impact significantly on patients' lives. We have evaluated patient preferences between raltitrexed ('Tomudex') and 5-fluorouracil-based chemotherapy regimens, with regard to side-effect attributes (raltitrexed and Mayo regimens) and administration attributes (raltitrexed, Mayo, De Gramont and Lokich regimens) in a study based on 82 patients with ACRC. Patients completed a series of rating tasks on how 'upsetting' these attributes were to them using a visual analogue scale (VAS) in a structured interview conducted by a research nurse. Mucositis and asthenia were the most and least upsetting side-effects, respectively. The side-effect profile of raltitrexed was clearly preferred by 78% of patients versus 14% for Mayo (P < 0.001). When side-effects and administration attributes were combined into an overall profile, 91% of patients selected raltitrexed as their clearly preferred regimen, versus 6% for Mayo (P < 0.001). The administration regimen of raltitrexed was ranked most acceptable (mean rank score 1.5 compared with Mayo 2.6, De Gramont 2.7, and Lokich 3.3). Given similar palliative effects, patients with ACRC exhibit preferences for raltitrexed over other regimens, based on administration and/or side-effect attributes. Such preferences should constitute an important part of decisions relating to the choice of chemotherapy regimen in ACRC.

Clodronate: a review of its use in breast cancer

Like other members of its class, the bisphosphonate clodronate (clodronic acid) inhibits bone resorption. The efficacy of oral clodronate 1600 mg/day in reducing the incidence of skeletal complications and metastasis development has been assessed in several clinical trials in patients with breast cancer. Long term use of oral clodronate significantly reduced the total cumulative incidence of skeletal events (including fractures, hypercalcaemia, and the need for radiotherapy for bone pain) compared with that in placebo recipients in 2 randomised double-blind placebo-controlled studies, each involving >100 patients. Significant differences in favour of clodronate were also seen in the frequency of some individual skeletal events in 1 trial. A nonblind trial in 302 patients considered to be at high risk of developing metastases found that, at a 3-year follow-up, significantly fewer patients who received clodronate for 2 years developed skeletal metastases than those in a control group. Clodronate recipients were also significantly less likely than controls to develop visceral metastases, and had significantly higher survival rates. A smaller double-blind placebo-controlled study in women with recurrent breast cancer found that clodronate significantly decreased the total number of new skeletal metastases, but not the number of patients who developed them. In a nonblind trial in 299 patients with node-positive breast cancer, however, the incidence of skeletal metastases did not differ significantly between patients who received clodronate for 3 years and those in a control group. In addition, clodronate recipients had a significantly greater incidence of nonskeletal metastases (local and visceral), and significantly lower survival rates. Intravenous or oral clodronate has been well tolerated in clinical trials. The most common adverse effects reported were mild gastrointestinal disturbances such as nausea, vomiting and diarrhoea. All these events were transient, and usually resolved without stopping treatment.

CONCLUSIONS

Clodronate is a well tolerated bisphosphonate, available in both oral and intravenous forms, that significantly reduces the incidence of skeletal complications associated with breast cancer. Further research is needed to establish more clearly its efficacy in reducing metastasis development, to assess its efficacy compared with other bisphosphonates, and to determine which patients will benefit most from treatment. Currently, clodronate is probably most effective in the treatment and prevention of general skeletal complications in patients with breast cancer.

Chemosensitivity of micrometastases and circulating tumor cells to uracil and tegafur as evaluated using LacZ gene-tagged Lewis lung carcinoma cell

The chemosensitivity of the sequence of steps responsible for metastasis formation including circulating tumor cells and micrometastases to a 5-fluorouracil derivative (UFT) was examined with a novel micrometastasis model featuring Lewis lung carcinoma cells tagged with the bacterial LacZ gene and hygromycinR gene (hygR). Metastases in the lung could be specifically detected at the single-cell level by X-Gal staining after inoculation of LacZ-transfected tumor cells. Spontaneous metastasis in mice bearing subcutaneous primary tumors was significantly inhibited by UFT at doses of 15-20 mg/kg when it was orally administered from day 14, during the early stage of micrometastasis formation, but not by late administration from day 22. Experimental pulmonary metastasis was also inhibited without significant toxic side effects by oral administration of UFT at a daily dose of 20 mg/kg from day 4, when the tumor cells start new growth in the lung, but not by daily treatment from 8 days after intravenous injection. Oral administration of UFT had no effect on tumor cell arrest in the lung as detected by X-Gal staining. Furthermore, PCR analysis revealed that circulating tumor cells in the peripheral blood of mice bearing primary tumors after subcutaneous injection of hygR-tagged tumor cells were significantly reduced by the oral administration of UFT for 7 days in a dose-dependent manner. These results indicate that circulating tumor cells in the peripheral blood and micrometastases in the initial growth phase in the lungs are sensitive to this chemotherapeutic agent, and suggest that micrometastasis formation can be effectively inhibited by long-term oral administration of anticancer agents with minimal toxic side effects.

Clinical pharmacology of anticancer agents in relation to formulations and administration routes

In the past years, alternative administration routes and pharmaceutical formulations of anticancer agents have been investigated in order to improve conventional chemotherapy treatment. The impact of these adjustments on the pharmacokinetics and pharmacodynamics is discussed. A review of the literature shows many examples of alternative administration forms of anticancer agents with improved pharmacokinetics. Local administration routes have been investigated in order to reduce the systemic toxicity and to enhance the local efficacy of conventional chemotherapy. Oral administration of anticancer agents is preferred by patients for its convenience and its potential for outpatient treatment. In addition, oral administration facilitates a prolonged exposure to the cytotoxic agent. However, poor bioavailability and substantial interpatient variability are noted as limitations for oral chemotherapy. Increased tumour selectivity can also be achieved by the use of specific pharmaceutical formulations, such as liposomes and macromolecular drug conjugates. The composition of these formulations often determine the pharmacokinetic behaviour of the formulated drug. In conclusion, several alternative administration forms of anticancer agents have been designed in the past years, with the potential for improvement of conventional chemotherapy, however, more extensive clinical evaluation of these novel strategies is warranted to prove their real clinical value.

Multicenter phase II study of capecitabine in paclitaxel-refractory metastatic breast cancer

PURPOSE

Capecitabine is a novel, oral, selectively tumor-activated fluoropyrimidine carbamate. This large multicenter phase II trial tested the efficacy and safety of twice-daily oral capecitabine at 2,510 mg/m2/d given for 2 weeks followed by a 1-week rest period and repeated in 3-week cycles, in patients with paclitaxel-refractory metastatic breast cancer.

PATIENTS AND METHODS

Patients were to have received at least two but not more than three prior chemotherapeutic regimens, one of which had to have contained paclitaxel given for metastatic disease. One hundred sixty-three patients were entered onto the study at 25 centers, and 162 patients received capecitabine. One hundred thirty-five patients had bidimensionally measurable disease, and 27 patients had assessable disease.

RESULTS

The overall response rate was 20% (95% confidence interval, 14% to 28%). All responding patients were resistant to or had failed paclitaxel, and all had received an anthracycline. Three complete responses were seen, with complete response durations of 106, 109, and 194+ days. Median duration of response was 8.1 months, median survival time was 12.8 months, and the median time to disease progression was 93 days. The most common treatment-related adverse events were hand-foot syndrome, diarrhea, nausea, vomiting, and fatigue. Diarrhea (14%) and hand-foot syndrome (10%) were the only treatment-related adverse events that occurred with grade 3 or 4 intensity in more than 10% of patients.

CONCLUSION

Capecitabine is an active drug in the treatment of paclitaxel-refractory metastatic breast cancer. It has a favorable toxicity profile with the added advantage of being an oral drug administered at home.

Phase I and pharmacokinetic trial of oral irinotecan administered daily for 5 days every 3 weeks in patients with solid tumors

PURPOSE

We conducted a phase I dose-escalation trial of orally administered irinotecan (CPT-11) to characterize the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), pharmacokinetic profile, and antitumor effects in patients with refractory malignancies.

PATIENTS AND METHODS

CPT-11 solution for intravenous (IV) use was mixed with CranGrape juice (Ocean Spray, Lakeville-Middleboro, MA) and administered orally once per day for 5 days every 3 weeks to 28 patients. Starting dosages ranged from 20 to 100 mg/m2/d.

RESULTS

Grade 4 delayed diarrhea was the DLT at the 80 mg/m2/d dosage in patients younger than 65 years of age and at the 66 mg/m2/d dosage in patients 65 or older. The other most clinically significant toxicity of oral CPT-11 was neutropenia. A linear relationship was found between dose, peak plasma concentration, and area under the concentration-time curve (AUC) for both CPT-11 and SN-38 lactone, implying no saturation in the conversion of irinotecan to SN-38. The mean metabolic ratio ([AUC(SN-38 total) + AUC(SN-38G total)]/AUC(CPT-11 total)) was 0.7 to 0.8, which suggests that oral dosing results in presystemic conversion of CPT-11 to SN-38. An average of 72% of SN-38 was maintained in the lactone form during the first 24 hours after drug administration. One patient with previously treated colorectal cancer and liver metastases who received oral CPT-11 at the 80 mg/m2/d dosage achieved a confirmed partial response.

CONCLUSION

The MTD and recommended phase II dosage for oral CPT-11 is 66 mg/m2/d in patients younger than 65 years of age and 50 mg/m2/d in patients 65 or older, administered daily for 5 days every 3 weeks. The DLT of diarrhea is similar to that observed with IV administration of CPT-11. The biologic activity and favorable pharmacokinetic characteristics make oral administration of CPT-11 an attractive option for further clinical development.

5-fluorouracil: a pharmacological paradigm in the use of cytotoxics

1. Painstaking progress in drug development is well illustrated by 5-fluorouracil (5FU), originally designed 40 years ago as a fluorinated analogue of the naturally occurring base uracil. Innovative pharmacokinetic and pharmacodynamic strategies have seen significant clinical improvements for cancer patients over the past decade. 2. 5-Fluorouracil acts by three main mechanisms. Principally, the intermediate metabolite fluorodeoxyuridine monophosphate inhibits a key enzyme in pyrimidine biosynthesis, namely thymidylate synthase (TS). Additionally, 5FU is metabolized to ribo- and deoxy-ribonucleotides, which act as false bases for incorporation into RNA and DNA. 3. Biomodulation of 5FU has been attempted with methotrexate (MTX), folinic acid, interferons, cisplatin and radiotherapy. Methotrexate augments the actions of 5FU by inhibiting dihydrofolate reductase and decreasing the folate pool required for pyrimidine biosynthesis, inhibiting TS via MTX-polyglutamate and directly inhibiting purine biosynthesis. Interferons increase steady state concentrations of 5FU. 5-Fluorouracil enhances the cytotoxicity of cisplatin and radiotherapy by inhibiting DNA repair. Folinic acid enhances TS inhibition by increasing the intracellular pool of folates that stabilize the 5FU-TS complex. 4. 5-Fluorouracil has a short plasma half-life. Thymidylate synthase inhibition is limited to the S-phase of the cell cycle and only a small fraction of most cancer cells are in S-phase at any one time. Increased response rates seen with infusional protocols may reflect the effective recruitment of additional mechanisms of cytotoxicity, not dependent on cell cycle, including effects on RNA synthesis. 5. Patients with localized metastatic disease may benefit from locoregional treatments. These include hepatic intra-arterial therapy with related compounds, such as floxuridine, which reach high concentrations at sites of tumour, while systemic toxicities are minimized by efficient hepatic clearance. 6. Recent developments include orally bioavailable formulations, such as ftorafur, capecitabine and the combination of 5FU with the dihydropyrimidine phosphate dehydrogenase inhibitor ethynyluracil. Recognition of diurnal variation in the activity of such key enzymes as DPD has led to the administration of 5FU at regulated, variable infusion rates (chronomodulation). These promising pharmacological approaches may further improve clinical outcomes in common cancers.

Oral fluoropyrimidines in the treatment of colorectal cancer

5-Fluorouracil (5-FU) has been the mainstay of systemic therapy for colorectal cancer since its initial development 40 years ago. Efforts to improve the therapeutic index of 5-FU have included alteration of schedule and addition of biochemical modulators. An understanding of 5-FU mechanisms of action has resulted in major therapeutic advances in the past 10 years; however, a plateau has been reached in the efficacy of 5-FU, mandating a paradigm shift for those involved in colorectal cancer drug development. One direction vigorously pursued is the development of orally administered fluoropyrimidines that maintain or improve upon the effectiveness of intravenous 5-FU. In this paper the preclinical and clinical development of oral fluoropyrimidines and their modulators is reviewed, including UFT, capecitabine, ethynyluracil and S-1.

Dose-Intensified Chemotherapy for Breast Cancer: Present and Future Prospects

With the trend to maximize chemotherapy in breast cancer, the use of peripheral blood stem cells in addition to hematopoietic growth factors to alleviate myelosuppression caused by dose-intensified chemotherapy has been shown to be beneficial. In treatment of metastatic breast cancer, response rates and complete response rates as high as 100%and nearly 80%, respectively, have been reported. Such treatments have shown even greater promise in an adjuvant setting for high-risk breast cancer. High-dose chemotherapy studies, however, involve highly-selected patient populations who are generally compared with unselected patients, and controversy still surrounds the question of whether it is substantially superior to conventional-dose chemotherapy. There are now more than sufficient data to justify ongoing randomized trials, and the most important overall recommedation is to encourage patients to participate in these clinical trials.

Treatment of advanced gastric cancer with oral etoposide, leucovorin and tegafur: experience with an oral modification of the etoposide, leucovorin and 5-fluorouracil (ELF) regimen

Recent data have suggested enhanced therapeutic activity with prolonged administration of both etoposide as well as fluoropyrimidines in the treatment of gastrointestinal malignancies. Based on this rationale, we investigated the clinical effectiveness and tolerance of an oral modification of the widely applied etoposide, leucovorin and 5-fluorouracil (ELF) regimen in patients with advanced gastric cancer. 32 patients with advanced gastric cancer were treated with oral etoposide (100 mg), leucovorin (3 x 100 mg), and tegafur (3 x 200 mg) over 14-21 days for a maximum of six cycles. Objective response was seen in only 5 patients (16%), stable disease was documented in 7 (22%), while the remaining patients progressed during therapy. The median time to progression was 2.8 months (range 0.7-12 months) and median overall survival was 6 months (range 1-18+ months). Due to grade 3 nausea/emesis, 8 patients discontinued treatment prematurely, while 12 patients experienced anorexia and progressive weight loss. Haematological toxicity was modest, with 4 patients developing asymptomatic grade 3-4 granulocytopenia. We conclude that this oral combination regimen cannot be recommended for the treatment of advanced gastric cancer.

Oral treosulfan as second-line treatment in platinum-resistant ovarian cancer: a phase II study. The Danish Ovarian Cancer Study Group

OBJECTIVE

To evaluate the effect of oral treosulfan in patients with platinum-resistant ovarian cancer.

METHODS

A phase II trial of oral treosulfan 500 mg per day in 30 females with platinum resistant ovarian cancer. All patients had measurable or evaluable disease.

RESULTS

The treatment was well tolerated. One patient (3%) achieved a partial response lasting 12+ months. Seven patients had stable disease for 5.3 months (median) range 4.4-7.5 months. Median time to progression was 11.5 weeks (95% C.L. 11-12 weeks). Median survival was 31 weeks (95% C.L. 30-35 weeks).

CONCLUSION

Oral treosulfan in the present schedule is not recommended in platinum resistant ovarian cancer.

High dose oral tamoxifen and subcutaneous interferon alpha-2a for recurrent glioma

Chemotherapeutic regimens in present use for recurrent glioma have substantial toxicity. Activity against recurrent gliomas has been reported for both tamoxifen and interferon alpha, agents that have more acceptable toxicity profiles and that can be administered in an outpatient setting. We tested the efficacy and toxicity of the combination of high-dose tamoxifen and interferon alpha in adults with recurrent glioma in a phase II trial. Eligible patients had radiographically measurable recurrent gliomas of any grade after initial radiation therapy. Interferon-alpha [6 x 10(6) U subcutaneously three times per week] and tamoxifen (240 mg/m2/day orally) were administered continuously. Treatment response was assessed at 6 week intervals using clinical and radiographic criteria. Eighteen patients (11 males and 7 females) were enrolled. Median age was 41 years (range 23-61 years). All patients had gliomas that progressed after radiation therapy and nitrosourea chemotherapy. The histologic diagnosis of the original tumor was glioblastoma multiforme in 8 patients, anaplastic astrocytoma in 5 patients, astrocytoma in 4 patients and mixed malignant glioma in 1 patient. Reversible moderate to severe neurological toxicity manifested by dizziness and unsteady gait was seen at tamoxifen doses of 240 mg/m2/day. Although the initial tamoxifen dose was reduced to 120 mg/m2/day, moderate neurotoxicity was noted at this dose as well and the trial was closed early. The combination of oral tamoxifen (120 to 240 mg/m2/day) and subcutaneous interferon-alpha [6 x 10(6) U three times per week] was associated with significant neurotoxicity in this group of recurrent glioma patients, resulting in early study closure. Of 16 evaluable patients, 12 had progressive disease after one cycle of treatment, 3 had stable disease, and there was one minor response. Gradual dose escalation may be required if similar patients are to be treated with high dose tamoxifen in conjunction with interferon.