BACKGROUND

With modern multimodality therapy, patients with resected colorectal cancer (CRC) liver metastases (CLM) can experience up to 50-60 % 5-year survival. These improved outcomes have become more commonplace via achievements in multidisciplinary care, improved definition of resectability, and advances in technical skill.

CONCLUSIONS

Even patients with synchronous and/or extensive bilateral disease have benefited from novel surgical strategies. Treatment sequencing of synchronous CRC with CLM can be simplified into the following three paradigms: (classic colorectal-first), simultaneous (combined), or reverse approach (liver-first). The decision of whether to treat the CLM or CRC first depends on which site dominates oncologically and symptomatically. Oxaliplatin with 5-fluorouracil/leucovorin (FOLFOX) and irinotecan with 5-fluorouracil/leucovorin (FOLFIRI) are the foundations of modern chemotherapy. Although each regimen has positively impacted survivals, both have the potential for negative effects on the non-tumor liver. Oxaliplatin is associated with vascular injury (sinusoidal ballooning, microvascular injury, nodular regenerative hyperplasia, and long-term fibrosis) but not steatosis. Irinotecan has been associated with steatohepatitis, especially in patients with obesity and diabetes. Steatohepatitis from irinotecan is the only chemotherapy-associated liver injury (CALI) associated with increased mortality from postoperative hepatic insufficiency. Extended duration of preoperative chemotherapy is also associated with CALI.

CONCLUSIONS

To determine resectability and to prevent overtreatment with systemic therapy, all patients should receive high-quality cross-sectional imaging and be evaluated by a hepatobiliary surgeon before starting chemotherapy. Even as chemotherapy improves, liver surgeons will continue to play a central role in treatment planning by offering the best chance for prolonged survival-safe R0 resection with curative intent.

We studied the molecular basis of the up to 46-fold increased accumulation of folates and methotrexate (MTX) in human leukemia CEM-7A cells established by gradual deprivation of leucovorin (LCV). CEM-7A cells consequently exhibited 10- and 68-fold decreased LCV and folic acid growth requirements and 23-25-fold hypersensitivity to MTX and edatrexate. Although CEM-7A cells displayed a 74-86-fold increase in the reduced folate carrier (RFC)-mediated influx of LCV and MTX, RFC overexpression per se cannot induce a prominently increased folate/MTX accumulation because RFC functions as a nonconcentrative anion exchanger. We therefore explored the possibility that folate efflux activity mediated by members of the multidrug resistance protein (MRP) family was impaired in CEM-7A cells. Parental CEM cells expressed substantial levels of MRP1, MRP4, poor MRP5 levels, whereas MRP2, MRP3 and breast cancer resistance protein were undetectable. In contrast, CEM-7A cells lost 95% of MRP1 levels while retaining parental expression of MRP4 and MRP5. Consequently, CEM-7A cells displayed a 5-fold decrease in the [(3)H]folic acid efflux rate constant, which was identical to that obtained with parental CEM cells, when their folic acid efflux was blocked (78%) with probenecid. Furthermore, when compared with parental CEM, CEM-7A cells accumulated 2-fold more calcein fluorescence. Treatment of parental cells with the MRP1 efflux inhibitors MK571 and probenecid resulted in a 60-100% increase in calcein fluorescence. In contrast, these inhibitors failed to alter the calcein fluorescence in CEM-7A cells, which markedly lost MRP1 expression. Replenishment of LCV in the growth medium of CEM-7A cells resulted in resumption of normal MRP1 expression. These results establish for the first time that MRP1 is the primary folate efflux route in CEM leukemia cells and that the loss of folate efflux activity is an efficient means of markedly augmenting cellular folate pools. These findings suggest a functional role for MRP1 in the maintenance of cellular folate homeostasis.

BACKGROUND

Unresectable adenocarcinoma of the biliary tree are associated with a very poor prognosis. 5-fluorouracil (5-FU) combination regimens have produced objective response rates in approximately 10-20% of patients. Leucovorin increases the selective cytotoxicity of 5-FU. There also are encouraging reports of carboplatin in combination with 5-FU in other gastrointestinal tract malignancies.

METHODS

Fourteen consecutive eligible patients were treated with a combination of carboplatin, 300 mg/m2, intravenously (i.v.) on Day 1 only and 5-FU, 400 mg/m2, i.v. with leucovorin, 25 mg/m2, i.v. on Days 1-4. All patients were required to have a histologically confirmed diagnosis and measurable disease. Patients were evaluated for response, survival, and toxicity.

RESULTS

A total of 48 cycles of therapy were delivered. The median survival was 5 months. One patient achieved complete remission and two others partial remission, for a total response rate of 21.4%. Four additional patients had stable disease for a median duration of 4 months. The therapy was well tolerated, with moderate myelosuppression as the main dose-limiting toxicity.

CONCLUSIONS

The current combination regimen of leucovorin-modulated 5-FU with carboplatin is well tolerated with appropriate supportive care, produces significant objective responses in 21% of patients with biliary tree carcinoma, and should be considered for the treatment of this disease.

Twenty-nine children with acute lymphocytic leukemia were given 24-hr infusions of intermediate-dose methotrexate (MTX, 1000 mg/m2) with and without intrathecal (IT) MTX (12 mg/m2), followed by leucovorin rescue. There was substantial interpatient variability in MTX systemic clearance (98.3 +/- 51 ml/min/m2), inducing total steady-state serum MTX concentrations ranging from 5.4 to 33.7 microM. The cerebrospinal fluid (CSF) concentration at the end of the infusion was 0.27 (+/- 0.1) microM when no IT-MTX was given and correlated with total steady-state (24-hr) serum concentration of MTX. By stepwise regression, the CSF MTX concentration correlated better with the nonprotein bound (free) steady-state serum MTX concentration (r = 0.66, P less than 0.01) than with total steady-state serum MTX concentration. Mean CSF: serum MTX concentration ratio was 0.023 (+/- 0.04) when no IT MTX was given. When an IT MTX dose (12 mg/m2) was given at the start of the MTX infusion, the steady-state CSF MTX concentration was 1.1 (+/- 0.4) microM, leading to a mean CSF: serum ratio of 0.073 (+/- 0.05). Despite 7-hydroxy-MTX serum concentrations exceeding MTX concentrations immediately after infusion, 7-hydroxy-MTX was not detectable in CSF of most patients (21 of 29), and was less than 50% of the concurrent MTX concentration when detectable. These data establish the substantial interpatient variability in CSF distribution of MTX after intermediate-dose MTX infusions and establish a significant correlation between steady-state free concentration of MTX in serum and CSF MTX concentration.

"Second generation" combination chemotherapy regimens were developed in the 1980s with high activity in locally advanced and metastatic disease. Among them were etoposide plus doxorubicin plus cisplatin (EAP), etoposide plus 5-fluorouracil plus leucovorin (ELF), continuous infusion of 5-fluorouracil plus cisplatin (FP) and high-dose methotrexate plus S-fluorouracil plus doxorubicin (FAMTX). In locally advanced disease a resectability rate of +/- 50% was reported with these protocols. FAMTX was felt to be superior to 5-fluorouracil, doxorubicin and mitomycin (FAM), which regimen had been considered "standard" treatment for many years. Randomized studies, however, did not reveal significant differences among various second generation regimens. Future studies should focus on innovative protocols in advanced disease, the role of neoadjuvant chemotherapy in clinically staged locally advanced disease, the role of local "consolidation treatment," ie, radiotherapy or intraperitoneal chemotherapy after primary chemotherapy plus resection, and preoperative and postoperative chemotherapy in operable disease.

BACKGROUND

Diarrhea and oral mucositis are the most frequently reported gastrointestinal side effects caused by 5-fluorouracil (5-FU). Diarrhea may be severe in 10-30% of patients and is schedule-dependent. 5-FU-induced gastrointestinal toxicity predominantly affects the upper and the lower gastrointestinal tract. The current study describes 5-FU-induced small bowel toxicity as an entity that to the authors' knowledge has not been reported previously in patients with colon carcinoma receiving 5-FU-based therapy.

METHODS

The authors report a series of six patients with colorectal carcinoma who developed acute small bowel toxicity after treatment with 5-FU and leucovorin.

RESULTS

Six patients developed a clinical picture of acute abdominal pain and diarrhea. Small bowel damage was documented by laparotomy in two patients, by colonoscopy in one patient, and by abdominal computed tomography scan in three patients. The course was complicated by recurrence of symptoms in one patient who was rechallenged with 5-FU and leucovorin, but the remaining four patients were rechallenged safely with lower doses of 5-FU and leucovorin after the acute toxicity episode. A possible explanation for this toxicity is 5-FU-induced vasospasm and/or decrease in fibrinolytic activity that results in decreased mucosal blood flow.

CONCLUSIONS

5-FU-induced small bowel toxicity is a potentially severe toxicity that may occur in patients with colon carcinoma or other malignancies who are receiving 5-FU-based therapy. [See editorial on pages 1099-100, this issue.]

OBJECTIVE

A clinical trial for patients with gastric cancer amenable to curative resection was undertaken to determine feasibility and response to preoperative systemic chemotherapy followed by postoperative intraperitoneal (IP) chemotherapy.

METHODS

Thirty-eight patients with resectable gastric tumor received two cycles of protracted intravenous (IV)-infusion fluorouracil (5FU), 200 mg/m2/d, for 3 weeks with weekly IV leucovorin 20 mg/m2 and IV cisplatin 100 mg/m2 days 1 and 29. Resection of the gastric tumor followed within 3 weeks of completion of systemic chemotherapy. Those who had all visible tumor removed with clear margins received two cycles of IP floxuridine 3,000 mg (total dose) per day for 3 days and IP cisplatin 200 mg/m2 with IV sodium thiosulfate on the fourth day of IP therapy.

RESULTS

Thirty-seven of 38 patients (97%) received two cycles of systemic chemotherapy. Thirty-five of 38 patients (92%) underwent laparotomy for gastric tumor resection. Thirty-three patients (87%) had gastric resections performed; 29 (76%) had all visible tumor removed with microscopically negative margins. No operative mortality was encountered. Twenty-six patients (68%) received IP treatment. IV neoadjuvant treatment was well tolerated and resulted in 68% of the patients reporting improvement in abdominal pain, 45% objective remissions by computed tomography (CT), 38% objective remissions by gastroscopy and biopsy, and 8% had complete surgical pathologic response. Neutropenic sepsis during the IP treatment phase contributed to the only treatment-related death. Four of 29 completely resected patients (14%) have had tumor recurrence. The median follow-up time of patients remaining alive is now 19 months. The median survival for 38 patients entered onto this protocol has not been reached at 17+ months.

CONCLUSIONS

This novel approach to the treatment of adenocarcinoma of the stomach is feasible. The neoadjuvant systemic therapy results in significant primary tumor regression. The determination of whether systemic or IP components of the program contribute to decreased recurrence or increased survival awaits a prospectively randomized clinical trial.

Low folate is associated with poorer response to selective serotonin reuptake inhibitors (SSRIs) in major depressive disorder (MDD). Folate supplementation in MDD has been studied in other settings with promising results. The objective of this study was to assess the efficacy of methylfolate as an adjunctive treatment among adults with MDD and inadequate response to an SSRI. Twenty-two adults (59% female; mean age 45.2 +/- 11.0 years) with DSM-IV MDD, partial or nonresponse to an SSRI after at least 4 weeks of treatment, and a 17-item Hamilton Depression Rating Scale (HAM-D-17) score>> or = 12 were enrolled in this 8-week prospective open trial. Exclusion criteria included current use of anticonvulsants or psychotropics other than an SSRI, or B12 deficiency. Leucovorin (folinic acid), which is metabolized to methylfolate, was added to SSRIs at 15-30 mg/day. Folate levels rose from 28 +/- 19 ng/mL to 301 +/- 203 ng/mL (p < 0.001). HAM-D-17 scores among the 16 completers decreased from 19.1 +/- 3.9 to 12.8 +/- 7.0 (p < 0.01). However only 31% of completers and 27% of the intent-to-treat (ITT) sample achieved response >> or = 50% reduction in HAM-D-17 scores), and only 19% of completers and 18% of the ITT sample achieved remission (HAM-D-17 < or = 7). Leucovorin appears to be modestly effective as an adjunct among SSRI-refractory depressed individuals with normal folate levels. The application of leucovorin as an adjunct in the setting of refractory depression deserves further study.

BACKGROUND

Cardiotoxicity related to the widely used cytotoxic compound 5-fluorouracil (5-FU) is rare compared with the frequency observed with the use of anthracyclines. More effective protocols incorporating active biomodulatory compounds like folinic acid (FA) or combination chemotherapy change type and severity of toxicity as well. The objective of the current study was to assess cardiotoxicity of the combination 5-FU and folinic acid.

METHODS

The authors' multicenter experience with 390 patients treated for advanced gastrointestinal cancer with intermediate-dose folinic acid and 5-FU was reviewed.

RESULTS

The overall risk of cardiotoxicity was 3%, which is not significantly higher than that reported with 5-FU alone. Eight of 53 patients with a history of cardiac disease reported cardiac symptoms (15.1%), compared with 5 of 337 patients (1.5%) with a no history of cardiac disease. Median time to symptoms was 3 days (range, 2-6). Nine patients had symptoms resembling myocardial ischemia, one patient died due to assumed myocardial infarction related closely to fluorouracil treatment, four patients had supraventricular arrhythmia, and one patient had congestive heart failure. A history of cardiac disease was the only risk factor associated with cardiotoxicity. Relapses were frequent on reinstitution of therapy despite cardiac symptoms in the preceding cycle. Therapeutically or prophylactically administered nitrates had no significant effect.

CONCLUSIONS

Physicians should be aware of the cardiotoxic properties of active fluorouracil treatment. The combination of 5-FU and leucovorin does not differ from single-agent therapy in frequency or type of cardiotoxicity. Close monitoring of patients is mandatory, especially for those patients at high risk for cardiac side effects. Treatment should be discontinued if coronary symptoms develop, because neither effective treatment nor prophylaxis exists for such symptoms.

OBJECTIVE

This phase I study was conducted to establish the dose-limiting toxicities and maximum-tolerated dose of erlotinib, an oral epidermal growth factor receptor tyrosine kinase inhibitor, in combination with FOLFIRI, a standard regimen of irinotecan, leucovorin, and infusional 5-fluorouracil (5-FU) in patients with advanced colorectal cancer.

METHODS

The trial used a dose-escalation design beginning with 100 mg/day erlotinib continuously and dose-reduced FOLFIRI (150 mg/m2 i.v. day 1 irinotecan, 200 mg/m2 i.v. leucovorin, 320 mg/m2 i.v. bolus days 1 to 2 5-FU, and 480 mg/m2 i.v. 5-FU infusion over 22 hours, days 1 to 2) administered in 6-week cycles (three FOLFIRI treatments). Plasma sampling was performed for irinotecan, erlotinib, and 5-FU for pharmacokinetic analysis during cycle 1.

RESULTS

The study was halted after six patients at the lowest dose level due to unexpectedly severe toxicities, including disfiguring grade 2 rash (three patients), grade 3 diarrhea (three patients), and grade>> or = 3 neutropenia (three patients). All patients required some dose interruption or reduction of either erlotinib or FOLFIRI, and only one patient completed two 6-week cycles of therapy. Five patients had stable disease after one cycle, and one patient had a partial response. No plasma pharmacokinetic interaction was observed that could explain the observed increased toxicity.

CONCLUSIONS

FOLFIRI combined with erlotinib causes excessive toxicity at reduced doses. These findings contrast with available data regarding the optimal safety profile of trials combining small molecule epidermal growth factor receptor inhibitors with other conventional chemotherapy and highlight the need to perform safety-oriented studies of such combinations.

BACKGROUND

Unresectable biliary tract carcinoma (BTC) is associated with a very poor prognosis. To improve efficacy and tolerance of the 5-fluorouracil (5-FU)/cisplatin combination in BTC, we designed a new therapeutic schedule, the LV5FU2-P regimen.

METHODS

Twenty-nine patients with advanced or metastatic BTC were prospectively enrolled in the study. The treatment (LV5FU2-P regimen) consisted of a biweekly administration of a 2-h infusion of leucovorin 200 mg/m(2), a 400 mg/m(2) bolus of 5-FU followed by a 22-h continuous infusion of 600 mg/m(2) 5-FU on two consecutive days and cisplatin 50 mg/m(2) on day 2. Clinical symptoms, performance and weight changes were monitored.

RESULTS

Objective responses were observed in 10 patients (34%) (95% confidence interval 23% to 45%) including one complete response and nine partial responses (stabilization 38%, progression 28%). Median progression-free survival and overall survival were 6.5 and 9.5 months, respectively. Weight gain was observed in 45% of patients and performance status improved in 60%. One patient had a grade 4 thrombocytopenia, and grade 3 toxicity occurred in 41% of patients. There were no treatment-related deaths.

CONCLUSIONS

This study, one of the largest phase II trials performed for this disease, shows that the LV5FU2-P regimen is an active and well-tolerated chemotherapy for advanced and metastatic BTC.

OBJECTIVE

The aim of this study was to investigate the utility of quantitating thymidylate synthase (TS) in the primary tumor as a surrogate for metastatic disease sites to predict the likelihood of response and outcome to fluorouracil (FU) treatment in patients with metastatic colorectal cancer.

METHODS

TS protein expression was evaluated using the TS 106 antibody and the avidin biotin labeling immunohistochemical technique in primary tumor samples from 219 patients with metastatic colorectal cancer. The patients were a representative sample of those patients enrolled into the Eastern Cooperative Oncology Group E2290 protocol that evaluated five separate FU-containing regimens in patients with metastatic residual or recurrent colorectal carcinoma.

RESULTS

Our retrospective analysis found that the level and extent of TS protein expression in the primary tumor did not correlate with overall survival in patients with metastatic or recurrent colorectal cancer. A trend toward a direct correlation between the level of TS protein expression and response was noted in tumors that expressed high TS levels. This response advantage for patients expressing high TS levels in the primary tumor was apparent regardless of what FU-based treatment the patient received but was most apparent in the subgroup treated with leucovorin, in which the level of TS expression and response to FU and leucovorin reached statistical significance (P =.034). No significant interaction could be detected between the addition of leucovorin to FU and the level of TS expression in the primary tumor.

CONCLUSIONS

This study demonstrated that measurement of TS protein levels in the primary tumor tissue does not aid in predicting outcome or response to FU in a metastatic disease site. These assays must be performed on biopsy tissue from the metastatic disease site that is used to radiologically assess response and outcome to treatment.

OBJECTIVE

Methotrexate nephrotoxicity can lead to delayed methotrexate elimination and the development of life-threatening toxicity, which may not be preventable with the standard rescue agent leucovorin. In preclinical studies, we previously demonstrated that carboxypetidase-G2 (CPDG2) rapidly hydrolyzes methotrexate to nontoxic metabolites. A protocol for the compassionate use of CPDG2 in patients who develop nephrotoxicity while receiving high-dose methotrexate was therefore developed. The pharmacologic and clinical outcome of CPDG2 rescue administered with thymidine and leucovorin in 20 patients is presented here.

METHODS

Patients with high-dose methotrexate-induced renal dysfunction received one to three doses of CPDG2, 50 U/kg body weight intravenously (i.v.), thymidine 8 g/m2/d by continuous i.v. infusion, and standard pharmacokinetically guided leucovorin rescue. Plasma concentrations of methotrexate and its inactive metabolite 4-deoxy-4-amino-N10-methylpteroic acid (DAMPA) were measured before and after CPDG2 using high-pressure liquid chromatography (HPLC). Tolerance of CPDG2 and thymidine, development of methotrexate toxicities, and recovery of renal function were monitored.

RESULTS

Twenty patients who received high-dose methotrexate for osteosarcoma (n = 11), lymphoid cancers (n = 8), and gastric cancer (n = 1) developed nephrotoxicity (median serum creatinine, 3.2 mg/dL) and elevated plasma methotrexate concentrations (median, 201 mumol/L at hour 46). CPDG2 and thymidine rescue was well tolerated and resulted in a rapid 95.6% to 99.6% reduction in the plasma methotrexate concentration. Methotrexate-related toxicity was mild to moderate. Serum creatinine returned to normal values at a median of 22 days.

CONCLUSIONS

CPDG2, thymidine, and leucovorin rescue was highly effective in 20 patients at high risk for developing life-threatening methotrexate toxicity after the onset of methotrexate-induced nephrotoxicity and delayed methotrexate excretion.

Low dose pulse MTX was associated with the development of pancytopenia in six patients with RA. Two patients died. Factors implicated in the occurrence of this complication were renal impairment in five patients, medication errors by two patients, preexisting marrow injury from occult alcoholism in one patient, and an apparent idiosyncratic reaction to the drug in another. Medication errors were associated with the use of five or more medications, and the unusual schedule of administration of low dose MTX may also have been contributory. From a consideration of the clinical pharmacokinetics of MTX, we suggest other factors that may predispose to the occurrence of marrow toxicity: the presence of hypoalbuminemia, interactions between MTX and other protein bound or weakly acidic drugs, and the repetitive dosing schedule of low dose MTX. Based on our experience, patients with impaired renal function (creatinine greater than or equal to 2.0 mg/dL) should not receive MTX. Renal function should be monitored regularly during treatment with MTX, and blood counts should be observed carefully if a new drug is added or substituted. A 5 mg test dose of MTX before initiating weekly therapy may identify patients with severe hypersensitivity to the drug. The potential risks of using MTX in a patient unwilling to accept blood products should be acknowledged and discussed with the patient. Furthermore, we recommend the use of leucovorin if pancytopenia occurs, even if low or undetectable serum levels of MTX are present.

OBJECTIVE

The addition of oxaliplatin to fluorouracil (FU) and leucovorin (LV) improves the outcome of patients with colorectal cancer (CRC). This multicenter study evaluated FU/LV with or without oxaliplatin in patients with metastatic CRC after disease progression on sequential fluoropyrimidine and irinotecan.

METHODS

Two hundred fourteen patients were randomly assigned to receive LV 200 mg/m2 intravenously (IV) and FU 400 mg/m2 IV bolus, followed by FU 600 mg/m2 IV over 22 hours on days 1 and 2, every 2 weeks (LV5FU2); or LV and FU as described, plus oxaliplatin 85 mg/m2 IV over 2 hours on day 1 of the schedule (FOLFOX4). The primary end point was overall response.

RESULTS

Baseline characteristics were similar in the two treatment arms. Objective response (complete + partial) rates for LV5FU2 versus FOLFOX4 were 2% v 13% (P = .0027), respectively. Median time to disease progression was 2.4 v 4.8 months (P < .0001), and median survival was 11.4 v 9.9 months (P = .20) for LV5FU2 and FOLFOX4, respectively. Among the 72 patients who crossed over from LV5FU2 to FOLFOX4, 6% responded. Symptomatic improvement was significantly better for patients in the FOLFOX4 arm (32% v 18% for LV5FU2, P = .05). Grade 3/4 toxicities for LV5FU2 and FOLFOX4 were neutropenia (13% and 42%, respectively), diarrhea (6% and 16%, respectively), and overall neuropathy (0% and 6%, respectively).

CONCLUSIONS

In patients with metastatic CRC, the FOLFOX4 regimen was superior to LV5FU2 with a higher response rate and time to disease progression. FOLFOX4 is an effective regimen even after disease progression on two previous chemotherapy regimens with fluoropyrimidines and irinotecan.

The prognosis for gastric cancer patients who undergo noncurative resection is extremely poor. This study evaluated the effects of neoadjuvant chemotherapy for primary noncurative gastric cancer. Thirty-four patients with biopsy-proven noncurative gastric cancer were treated with either of two neoadjuvant chemotherapies: FEMTXP (5-fluorouracil, epirubicin, methotrexate, cisplatin) or THP-FLPM (pirarubicin, 5-fluorouracil, leucovorin, cisplatin, mitomycin C). Noncurability was determined by conventional staging procedures, staging laparoscopy, and exploratory laparotomy. After chemotherapy the resectability of the tumors was reassessed. Patients who were judged to be candidates for curative resection underwent salvage surgery. Of the final 33 patients, 8 (24.2%) showed a major response [0 complete response (CR), 8 partial response (PR)]. In three patients the second laparoscopy revealed disappearance of the peritoneal metastasis. Of the 33 patients, 14 (42.4%) underwent salvage surgery, including 8 curative resections (2 curability A, 6 curability B). Pathologic examinations revealed a grade 2 response in eight patients but no grade 3 response. Univariate analysis showed the following to be significant prognostic factors: histology type (differentiated type vs. undifferentiated type; p = 0.035), T4 as a noncurative factor (T4 vs. T3 or less; p = 0.025), clinical response (PR + no change vs. progressive disease; p = 0.002), and salvage surgery (resected vs. unresected; p = 0.001). Among these factors, salvage surgery was found to be the only independent prognostic factor by multivariate analysis, with a relative risk of 0.253 and a 95% confidence interval of 0.066 to 0.974. The treatment was well tolerated. Major toxicities of WHO grade 3 or more were leukopenia in 20 (60.6%), gastrointestinal toxicities in 5 (15.2%), renal toxicities in 2 (6.1%), and alopecia in 1 (3.0%). In conclusion, neoadjuvant chemotherapy is effective for primary noncurative gastric cancer when salvage surgery can be performed. A chemotherapy regimen with a higher complete response rate would improve the prognosis of this dismal disease even more.

The overall 5-year survival rate for patients with metastatic colorectal cancer (CRC) is less than 10%. Median survival with 5-fluorouracil (5-FU)/leucovorin (LV) therapy is approximately 12 months. Recent additions to the chemotherapy armamentarium for this disease have begun to prolong median survival times. In trials in which patients are exposed to all three approved chemotherapy agents, oxaliplatin, irinotecan, and 5-FU/LV, or capecitabine during the course of their disease, median survival has reached 20 months. The addition of oxaliplatin and irinotecan to 5-FU/LV regimens has also led to the maintenance of quality of life for longer intervals than were traditionally observed with 5-FU/LV alone. Current standard first-line regimens for metastatic CRC are FOLFOX (infusional 5-FU/LV with oxaliplatin) and FOLFIRI (infusional 5-FU/LV with irinotecan). The addition of bevacizumab to a two-drug regimen (irinotecan with 5-FU/LV) prolongs median survival to 20 months, with a modest amount of additional toxicity. Improvements in this median survival have not yet been realized with modifications to the current standard regimens; however, the oral agent capecitabine appears to be a reasonable substitute for infusional 5-FU/LV in combination regimens or as a single agent, with the advantage of reducing the inconvenience of the long infusion time. Ongoing investigations will identify a place for capecitabine, epidermal growth factor inhibitors, and new cytotoxics in the treatment of metastatic CRC.

'Tomudex' (ZD1694), a direct and specific thymidylate synthase (TS) inhibitor entered phase III studies in November 1993. We present here the first analysis of a randomised multicentre, international phase III study. 439 patients with previously untreated advanced colorectal cancer were randomised to Tomudex 3.0 mg/m2 given once every 3 weeks or 5-fluorouracil (5-FU) 425 mg/m2 and leucovorin (LV) 20 mg/m2 for 5 days (the Mayo regimen), given every 4-5 weeks. Patients were evaluated weekly for toxicity and every 12 weeks for objective response. The two groups were well matched in terms of demographic characteristics. The mean age of the patients was 61 years and most had either liver (78%) or lung (25-29%) metastases. Ninety seven per cent of patients allocated to Tomudex and 94% of those allocated to 5-FU plus LV had measurable disease. Response was assessed using WHO/UICC criteria; all response data were source validated; 19.8% of patients who received Tomudex and 12.7% of patients who received 5-FU plus LV had complete or partial responses (P = 0.059, odds ratio 1.7, 95% confidence limits 0.98-2.81). There were no statistically significant differences in time to progression or survival between the two groups. Patients who received Tomudex spent a substantially shorter time in hospital for dosing and had significantly lower rates of grade 3 and 4 toxicities such as leucopenia and mucositis. Patients who received Tomudex had a significantly higher incidence of reversible grade 3 or 4 increase in transaminases, which appear to be of limited clinical significance. Improvement in quality of life, weight gain and performance status was seen in both groups. Tomudex has benefits in terms of higher response rates, reduced toxicity and more frequent palliative benefits when compared with 5-FU plus LV in the management of advanced colorectal cancer, and has a more convenient administration schedule.

BACKGROUND

FOLFOX2, a bimonthly regimen of high-dose leucovorin (LV), 48-hour continuous infusion of 5-fluorouracil (5-FU) (LV-5-FU) and oxaliplatin (100 mg/m2) produced a high response rate (46%; 95% confidence interval (95% CI): 31%-60%) in 5-FU pre-treated patients with metastatic colorectal cancer. In this phase II study, pre-treated patients were given a lower dose of oxaliplatin to reduce the toxic effects of the regimen.

METHODS

Thirty patients with advanced colorectal adenocarcinoma and progression while receiving bimonthly LV-5-FU (LV: 500 mg/m2, 5-FU: 1.5-2 g/m2/22 hours, days 1-2, every two weeks), were given the same LV-5-FU schedule with the addition of oxaliplatin (85 mg/m2) every two weeks (FOLFOX3).

RESULTS

The main toxic effects were peripheral neuropathy (90%) with four severe sensitive neuropathies (WHO grade 2: 13%). The response rate was 20% (95% CI: 8%-39%). Median progression-free survival was 26 weeks, median survival was 57 weeks from the start of FOLFOX3 and median duration of the response was 37 weeks.

CONCLUSIONS

Results obtained with FOLFOX3 confirmed the synergy between oxaliplatin and 5-FU in 5-FU-resistant metastatic colorectal cancer. However, the response rate seems to be lower than that obtained with FOLFOX2. Further studies to determine the best oxaliplatin dose intensity are in progress.

BACKGROUND

Decision analysis in hospital-based settings is becoming more common place. The application of modeling and simulation approaches has likewise become more prevalent in order to support decision analytics. With respect to clinical decision making at the level of the patient, modeling and simulation approaches have been used to study and forecast treatment options, examine and rate caregiver performance and assign resources (staffing, beds, patient throughput). There us a great need to facilitate pharmacotherapeutic decision making in pediatrics given the often limited data available to guide dosing and manage patient response. We have employed nonlinear mixed effect models and Bayesian forecasting algorithms coupled with data summary and visualization tools to create drug-specific decision support systems that utilize individualized patient data from our electronic medical records systems.

METHODS

Pharmacokinetic and pharmacodynamic nonlinear mixed-effect models of specific drugs are generated based on historical data in relevant pediatric populations or from adults when no pediatric data is available. These models are re-executed with individual patient data allowing for patient-specific guidance via a Bayesian forecasting approach. The models are called and executed in an interactive manner through our web-based dashboard environment which interfaces to the hospital's electronic medical records system.

RESULTS

The methotrexate dashboard utilizes a two-compartment, population-based, PK mixed-effect model to project patient response to specific dosing events. Projected plasma concentrations are viewable against protocol-specific nomograms to provide dosing guidance for potential rescue therapy with leucovorin. These data are also viewable against common biomarkers used to assess patient safety (e.g., vital signs and plasma creatinine levels). As additional data become available via therapeutic drug monitoring, the model is re-executed and projections are revised.

CONCLUSIONS

The management of pediatric pharmacotherapy can be greatly enhanced via the immediate feedback provided by decision analytics which incorporate the current, best-available knowledge pertaining to dose-exposure and exposure-response relationships, especially for narrow therapeutic agents that are difficult to manage.

Trimetrexate, a highly lipid-soluble quinazoline antifolate now undergoing trials as an anticancer agent, was found to be a potent inhibitor of the dihydrofolate reductase (DHFR) isolated from Toxoplasma gondii. The concentration required for 50% inhibition of protozoal DHFR was 1.4 nM. As an inhibitor of this enzyme, trimetrexate was almost 600-fold (amount of antifolate required to inhibit catalytic reaction by 50%) and 750-fold (inhibition constant) more potent than pyrimethamine, the DHFR inhibitor currently used to treat toxoplasma infection. When the protozoan was incubated with 1 microM trimetrexate, the drug rapidly reached high intracellular concentrations. Since toxoplasma organisms lack a transmembrane transport system for physiologic folates, host toxicity can be prevented by co-administration of the reduced folate, leucovorin, without reversing the antiprotozoal effect. The effectiveness of trimetrexate against toxoplasma was demonstrated both in vitro and vivo. Proliferation of toxoplasma in murine macrophages in vitro was completely inhibited by exposure of these cells to 10(-7) M trimetrexate for 18 h. When used alone, trimetrexate was able to extend the survival of T. gondii-infected mice.

We examined the substrate specificity of human organic anion transporter (hOAT) 1 and hOAT3 for various cephalosporin antibiotics, cephaloridine, cefdinir, cefotiam, ceftibuten, cefaclor, ceftizoxime, cefoselis and cefazolin by using HEK293 cells stably transfected with hOAT1 or hOAT3 cDNA (HEK-hOAT1, HEK-hOAT3). Additionally, we examined the uptake of various compounds by these transfectants. The mRNA level of hOAT3 in HEK-hOAT3 was about three-fold that of hOAT1 in HEK-hOAT1. Functional expression of hOAT1 and hOAT3 was confirmed by the uptake of p-[14C]aminohippurate and [3H]estrone sulfate, respectively. p-[14C]Aminohippurate, [3H]estrone sulfate, [14C]captopril, [3H]methotrexate, [3H]ochratoxin A, [3H]leucovorin and [3H]cimetidine were shown to be substrates for hOAT1 and hOAT3, and [3H]dehydroepiandrosterone sulfate was shown to be a substrate for hOAT3. All cephalosporin anitibiotics tested were shown to inhibit the uptake of p-[14C]aminohippurate and [3H]estrone sulfate via hOAT1 and hOAT3, respectively, in a dose-dependent manner, and the IC50 values of these antibiotics, except for cefaclor, for the hOAT1-mediated uptake of p-[14C]aminohippurate were within four-fold of those for the hOAT3-mediated uptake of [3H]estrone sulfate. The uptake of cephaloridine, cefdinir and cefotiam by HEK-hOAT3 was 35-50-fold greater than that by control cells. Moreover, the accumulation of the other cephalolsporin antibiotics was significantly greater in HEK-hOAT3 than in control cells. In contrast, the uptake of these antibiotics by HEK-hOAT1 was within two-fold of that by control cells. In conclusion, hOAT3 plays a more important role than hOAT1 in the renal secretion of cephalosporin antibiotics.

Combination chemotherapy with oxaliplatin plus 5-fluorouracil/leucovorin (FOLFOX) or irinotecan plus 5-fluorouracil/leucovorin (FOLFIRI) has become a standard regimen for advanced or recurrent colorectal cancer. Numerous studies have reported that long-term use of FOLFOX or FOLFIRI leads to better survival for these patients. Thus, control of the toxicity of these drugs may be crucial to prolonging survival. Fucoidan is one of the major sulfated polysaccharides of brown seaweeds and exhibits a wide range of biological activities. In the present study, we analyzed the effect of fucoidan on suppressing the toxicity of anti-cancer drugs. A total of 20 patients with unresectable advanced or recurrent colorectal cancer scheduled to undergo treatment with FOLFOX or FOLFIRI were randomly allocated into a fucoidan treatment group (n=10) and a control group without fucoidan treatment (n=10). Results showed that fucoidan regulated the occurrence of fatigue during chemotherapy. Chemotherapy with fucoidan was continued for a longer period than chemotherapy without fucoidan. Additionally, the survival of patients with fucoidan treatment was longer than that of patients without fucoidan, although the difference was not significant. Thus, fucoidan may enable the continuous administration of chemotherapeutic drugs for patients with unresectable advanced or recurrent colorectal cancer, and as a result, the prognosis of such patients is prolonged.