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Purpose: The benefit of salvage chemotherapy is modest in metastatic urothelial cancer. We conducted a randomized, noncomparative phase II study to measure the efficacy of cetuximab with or without paclitaxel in patients with previously treated urothelial cancer., Patients and Methods: Patients with metastatic urothelial cancer who received one line of chemotherapy in the perioperative or metastatic setting were randomly assigned to 4-week cycles of cetuximab 250 mg/m(2) with or without paclitaxel 80 mg/m(2) per week. We used early progression as an indicator of futility. Either arm would close if seven of the initial 15 patients in that arm progressed at the first disease evaluation at 8 weeks., Results: We enrolled 39 evaluable patients. The single-agent cetuximab arm closed after nine of the first 11 patients progressed by 8 weeks. The combination arm completed the full accrual of 28 patients, of whom 22 patients (78.5%) had visceral disease. Twelve of 28 patients had progression-free survival greater than 16 weeks. The overall response rate was 25% (95% CI, 11% to 45%; three complete responses and four partial responses). The median progression-free survival was 16.4 weeks (95% CI, 12 to 25.1 weeks), and the median overall survival was 42 weeks (95% CI, 30.4 to 78 weeks). Treatment-related grade 3 and 4 adverse events that occurred in at least two patients were rash (six cases), fatigue (five cases), and low magnesium (three cases)., Conclusion: Although it had limited activity as a single agent, cetuximab appears to augment the antitumor activity of paclitaxel in previously treated urothelial cancers. The cetuximab and paclitaxel combination merits additional study to establish its role in the treatment of urothelial cancers.

Purpose: Temsirolimus is an effective treatment for renal cell carcinoma. It is associated with increases in serum cholesterol, triglyceride, and glucose. We investigated whether changes of these biomarkers could predict its efficacy., Experimental Design: We examined serial measurements of cholesterol, triglycerides, and glucose from patients randomized to IFN or temsirolimus in the Global Advanced Renal Cell Carcinoma Trial. Using time-dependent proportional hazards models, we quantified the association between changes in these biomarkers from baseline with overall survival (OS) and progression-free survival (PFS). We also assess the extent to which changes of these biomarkers predict the effects of temsirolimus on survival., Results: Temsirolimus was associated with larger mean increases in cholesterol (1.02 mmol/L; P < 0.0001), triglycerides (0.32 mmol/L; P = 0.0008), and glucose (1.28 mmol/L; P < 0.0001) compared with IFN and improved survival rate (OS: HR = 0.76, P = 0.02; PFS: HR = 0.70, P = 0.001). Cholesterol increase during study was associated with longer survival (OS: HR = 0.77 per mmol/L, P < 0.0001; PFS: HR = 0.81 per mmol/L; P < 0.0001). Temsirolimus effect on cholesterol predicted its effect on survival with no additional survival advantage observed after adjusting for cholesterol change during study (OS: HR = 1.14, P = 0.37; PFS: HR = 0.88, P = 0.35). Temsirolimus effect on triglycerides or glucose did not predict its effect on survival, with survival advantage in favor of temsirolimus still observed after adjusting for these factors (P = 0.003 and P = 0.002)., Conclusion: Cholesterol increase is a potential predictor for temsirolimus efficacy. Longer survival in patients treated with temsirolimus was observed in those with larger increases in cholesterol. Prospectively designed biomarker studies of temsirolimus or other mTOR inhibitors are recommended.

Purpose: Pneumonitis has occurred in patients treated with inhibitors of the mammalian target of rapamycin (mTOR). In a phase III study of patients with previously untreated, poor-prognosis, advanced renal cell carcinoma (ARCC), the mTOR inhibitor temsirolimus improved survival compared with interferon. We performed a retrospective, independent, blinded radiographic review of chest computed tomography (CT) images of patients in this study to characterize temsirolimus-related pneumonitis., Patients and Methods: Patients were treated with intravenous temsirolimus 25 mg once weekly or subcutaneous interferon alfa 3 million units, with an increase to 18 million units, thrice weekly. Drug-related pneumonitis was identified based on sequential chest CT images, required every 8 weeks, showing changes consistent with pneumonitis and not pneumonia (infection) or disease progression as correlated with clinical data. Cumulative probability of drug-related pneumonitis was estimated using the Kaplan-Meier method., Results: Eight (6%) of 138 and 52 (29%) of 178 evaluable patients on interferon and temsirolimus treatment, respectively, developed radiographically identified drug-related pneumonitis. Time to onset of pneumonitis was significantly shorter on the temsirolimus arm than on the interferon arm (log-rank P < .001). Estimated cumulative probability of pneumonitis at 8 and 16 weeks from first dose was 21% and 31%, respectively, on the temsirolimus arm and 6% and 8%, respectively, on the interferon arm. Respiratory symptoms were observed around time of onset of radiographically diagnosed temsirolimus-related pneumonitis in 16 (31%) of 52 patients., Conclusion: Patients with ARCC receiving temsirolimus should be monitored closely for development of pneumonitis, and their management should be altered if clinical symptoms appear.

Purpose: To investigate the efficacy and safety of axitinib, an oral, potent, and selective inhibitor of vascular endothelial growth factor (VEGF) receptors 1, 2, and 3 in patients with metastatic renal cell carcinoma (mRCC) refractory to prior therapies that included, but were not limited to, sorafenib., Patients and Methods: In this multicenter, open-label, phase II study, patients with sorafenib-refractory mRCC received a starting dose of axitinib 5 mg orally twice daily. A one-arm, single-stage design was used to estimate the primary end point of objective response rate (ORR), defined by RECIST (Response Evaluation Criteria in Solid Tumors). Secondary end points included safety, duration of response, progression-free survival (PFS), overall survival (OS), and patient-reported outcomes., Results: Of 62 patients recruited, 100% had received prior sorafenib, and 74.2% had received two or more prior systemic treatments. The axitinib dose was titrated to greater than 5 mg twice daily in 53.2% of patients, and 35.5% of patients had the dose modified to less than 5 mg twice daily. In 62 patients evaluable for response, the ORR was 22.6%, and the median duration of response was 17.5 months. Median PFS and OS times were 7.4 months (95% CI, 6.7 to 11.0 months) and 13.6 months (95% CI, 8.4 to 18.8 months), respectively. All-causality grade 3 to 4 adverse events included hand-foot syndrome (16.1%), fatigue (16.1%), hypertension (16.1%), dyspnea (14.5%), diarrhea (14.5%), dehydration (8.1%), and hypotension (6.5%)., Conclusion: Axitinib has antitumor activity in patients with mRCC refractory to prior VEGF-targeted therapy, including sorafenib. Toxicities were mild to moderate and were manageable. A randomized, phase III trial to compare axitinib with sorafenib in patients who have mRCC refractory to one prior first-line therapy regimen is underway.

Purpose Exploratory subgroup analyses from the phase 3 global advanced renal cell carcinoma (ARCC) trial were conducted to assess the influence of tumor histology on outcome of patients treated with temsirolimus (Torisel) or interferon-alpha (IFN). Patients and methods Patients with ARCC including clear cell and other types such as papillary and chromophobe histologies received either IFN (3 million units [MU] subcutaneously three times weekly, escalating to 18 MU) or temsirolimus (25 mg intravenously weekly). Results Approximately 80% of patients had clear cell and 20% of patients had other histologies, the majority of which were papillary. Patients with clear cell and other RCC histologies, treated with temsirolimus, demonstrated comparable median overall and progression-free survival. In contrast, patients with other RCC histologies, treated with IFN, demonstrated shorter median overall and progression-free survival than patients with clear cell RCC. Hazard ratios for death for treatment with temsirolimus versus IFN were less than 1 for patients regardless of tumor histology. For patients treated with temsirolimus, 59% with clear cell and 68% with other RCC histologies experienced tumor reductions. For patients treated with IFN, 35% with clear cell and 14% with other RCC histologies had tumor reductions. However, temsirolimus did not appear to improve the objective response rate compared to IFN. Temsirolimus resulted in a superior clinical benefit rate compared with IFN, regardless of tumor histology. Conclusion Temsirolimus appears to be efficacious in patients with clear cell and non-clear cell histologies and can, therefore, be used for the treatment of all types of RCC.

Based on the pre-clinical spectrum of activity in taxane-resistant cell lines, we evaluated KOS-862 (epothilone D; 12,13-desoxyepothilone B) as second-line chemotherapy in androgen-independent prostate cancer.Thirty-eight men with metastatic androgen-independent prostate cancer and evidence of progression following docetaxel-based chemotherapy were treated with KOS-862, 100 mg/m(2) (maximum of 240 mg) i.v. weekly for 3 weeks, repeated every 4 weeks. The primary objective for this study was to determine the antitumor activity, measured by PSA decline by more then 50% confirmed 4 weeks later. Two patients (5.3%, 90% CI 1-16%) met criteria for confirmed PSA decline. While both of these patients had previously been treated with docetaxel, neither had confirmed docetaxel-refractory disease. None of the 24 patients with measurable disease had a confirmed partial response. Seventy-three percent of patients had an adverse event leading to dose delay, reduction, or treatment discontinuation. Neurological toxicity and fatigue predominated. Seventeen patients (44.7%) had treatment related grade 3 neurological adverse events including peripheral sensory neuropathy (n = 4, 10.5%), ataxia (n = 3, 7.9%), peripheral motor neuropathy (n = 1, 2.6%), involuntary muscle contractions (n = 1, 2.6%) and neuropathic pain (n = 1, 2.6%). One subject (2.6%) had a grade 4 treatment peripheral motor neuropathy. Further study of this dose and schedule of KOS-862 in this patient population cannot be recommended due to both lack of activity and excessive toxicity.

Background: Interferon alfa is widely used for metastatic renal-cell carcinoma but has limited efficacy and tolerability. Temsirolimus, a specific inhibitor of the mammalian target of rapamycin kinase, may benefit patients with this disease., Methods: In this multicenter, phase 3 trial, we randomly assigned 626 patients with previously untreated, poor-prognosis metastatic renal-cell carcinoma to receive 25 mg of intravenous temsirolimus weekly, 3 million U of interferon alfa (with an increase to 18 million U) subcutaneously three times weekly, or combination therapy with 15 mg of temsirolimus weekly plus 6 million U of interferon alfa three times weekly. The primary end point was overall survival in comparisons of the temsirolimus group and the combination-therapy group with the interferon group., Results: Patients who received temsirolimus alone had longer overall survival (hazard ratio for death, 0.73; 95% confidence interval [CI], 0.58 to 0.92; P=0.008) and progression-free survival (P<0.001) than did patients who received interferon alone. Overall survival in the combination-therapy group did not differ significantly from that in the interferon group (hazard ratio, 0.96; 95% CI, 0.76 to 1.20; P=0.70). Median overall survival times in the interferon group, the temsirolimus group, and the combination-therapy group were 7.3, 10.9, and 8.4 months, respectively. Rash, peripheral edema, hyperglycemia, and hyperlipidemia were more common in the temsirolimus group, whereas asthenia was more common in the interferon group. There were fewer patients with serious adverse events in the temsirolimus group than in the interferon group (P=0.02)., Conclusions: As compared with interferon alfa, temsirolimus improved overall survival among patients with metastatic renal-cell carcinoma and a poor prognosis. The addition of temsirolimus to interferon did not improve survival. (ClinicalTrials.gov number, NCT00065468 [ClinicalTrials.gov].)., (Copyright 2007 Massachusetts Medical Society.)

We propose a new paradigm for the clinical evaluation of new cancer therapies. It entails adjusting the search for the optimal dose on the basis of measurable patient characteristics that may be predictive of adverse responses to treatment, and extending this search beyond phase I and into phases II and III. We provide examples of (a) how the fine-tuning of dose may involve utilization of patient-specific attributes to obtain a personalized treatment regimen, and (b) how novel methods for phase I design can be used to update the working dose for the conduct of phase II and III cancer clinical trials. These examples should be interpreted as an enticement for the development of new methods to implement the proposed new paradigm.

Dolastatin-10 is a natural, cytotoxic peptide with microtubule-inhibitory and apoptotic effects. It has demonstrated in vitro and in vivo efficacy in the DU-145 human prostate cancer model. A Phase II clinical trial was designed in patients with hormone-refractory prostate cancer. Dolastatin-10 was administered at a dose of 400 microg/m2 i.v. every 3 weeks. Dose escalation to 450 microg/m2 was permitted. Toxicity evaluation was conducted every 2 weeks, and assessment of response was done at the end of every two cycles. Sixteen patients were enrolled between October 1998 to December 1999. The median age was 71 years (range, 59-79 years). Median prostate-specific antigen value was 108 ng/ml (range, 15.3-1672 ng/ml). Of the 15 eligible patients, 7 were Caucasian and 8 were African-American. Eight patients had bone-only metastases, and seven had measurable disease with or without bone metastases. A total of 56 cycles have been administered. Only 2 patients required dose adjustment because of toxicity, and in 5 patients, dose escalation was feasible to 450 microg/m2. The major toxicities observed were grade 3 and 4 neutropenia in 8 patients and grade 3 neuropathy in 1 patient. All 15 patients are evaluable for response. Three patients demonstrated stable disease; 2 of these had bone disease, and 1 had nodal metastasis. All others had disease progression. Dolastatin-10 is very well tolerated in this elderly, pretreated population but lacks significant clinical activity as a single agent.

Metastatic germ-cell tumors of the testis are highly curable with cisplatin-based chemotherapy. Although cisplatin-based chemotherapy is generally well tolerated and rarely causes severe neurotoxicity, there is little information to guide the treatment of patients with neuromuscular disorders. The authors report the successful treatment of a patient with testicular cancer and spinal muscular atrophy, an inherited degenerative neuromuscular disease.

Estramustine (EM), an antimicrotubule agent, is effective against hormone-refractory prostate cancer when used in combination with vinblastine or paclitaxel. To understand the effect of EM on beta-tubulin, a cellular target for this class of drugs, human prostate carcinoma cells (DU-145) were made resistant to EM, and two cell lines were selected at 12- (EM-12) and 15-microMolar (EM-15) concentrations of the drug. These cell lines exhibited 8- to 9-fold resistance to EM and 2- to 4-fold cross-resistance to paclitaxel. Immunofluorescent staining of the cells with beta-tubulin isotype-specific antibodies showed an approximately 6-fold increase in the beta(III)-tubulin levels and moderate increase in overall beta-tubulin levels in EM-resistant cells when compared to DU-145 cells. This increase of beta(III) isotype was confirmed by Western analysis. A reverse transcriptase-PCR assay was also employed using beta-tubulin isotype-specific primers to quantify beta-tubulin isotype RNA. A 4-fold increase in beta(III) and a 3-fold increase in beta(IV alpha) transcript were seen in both EM-resistant cell lines. These results indicate that overexpression of specific beta-tubulin isotypes may play a role in the cellular defense against EM and other antimicrotubule agents.

Inhibition of pyrimidine and purine synthesis has been demonstrated to potentiate 5-fluorouracil (5-FU) activity in preclinical models. Low-dose phosphonacetyl-L-aspartate (PALA) potentiates the incorporation of 5-FU into RNA, without detectably increasing its toxicity. 6-Methylmercaptopurine riboside (MMPR) results in inhibition of purine biosynthesis with elevation of phosphoribosyl pyrophosphate (PRPP), which in turn is believed to increase the phosphorylation and intracellular retention of 5-FU. We conducted a phase I clinical trial to determine the maximum tolerated dose of 5-FU in combination with low-dose PALA and a biochemically-optimized dose of MMPR. The regimen consisted of PALA 250 mg/m2 given on day 1, followed 24 h later by MMPR 150 mg/m2, and escalating doses of 5-FU from 1625 to 2600 mg/m2 by 24 h continuous infusion. This regimen was repeated weekly. A group of 29 patients with a diagnosis of malignant solid tumor were entered; their median performance status was 1. The dose-limiting toxicity was mucositis, while other gastrointestinal toxicity was minimal. Two patients also experienced ischemic chest pain during the 5-FU infusion. The maximum tolerated dose of 5-FU in this combination was 2600 mg/m2. Several responses were observed including a complete remission in a previously treated breast cancer patient and two partial responses in breast and colon cancer. MMPR pharmacokinetics were obtained from urine analyses in 21 patients on this trial; there was no correlation between the pharmacokinetics of MMPR and the toxicity observed. This regimen was well tolerated and phase II trials are warranted using PALA 250 mg/m2, MMPR 150 mg/m2, and 5-FU 2300 mg/m2 by continuous infusion over 24 h.

Systemic chemotherapy with currently available agents has not improved survival for patients with hormone refractory prostate cancer (HRPC), consequently, the evaluation of new agents is warranted. Topotecan is a specific inhibitor of topoisomerase I with broad antitumor activity in preclinical studies. The purpose of this phase II trial was to determine the objective response rate of topotecan administered as a 30 minute infusion for five consecutive days in men with metastatic HRPC. Thirty-four evaluable patients were treated with topotecan 1.1-1.5 mg/m2 as a 30 minute infusion daily for five days, repeated every three weeks until disease progression or unacceptable toxicity. Response was assessed with a combination of standard solid tumor response criteria and the serum prostate specific antigen (PSA) for patients with bidimensionally measurable disease, and by serial measurements of the PSA in patients with bone only (evaluable) disease. One of 13 patients (7.6%) with measurable soft tissue disease had a PR in nodal sites. Of 21 patients with only osseous metastases, 1 (4.7%) had improvement in bone scan. Six of the 34 evaluable patients (17.6%) had the serum PSA decrease by > or = 50% and 2 (5.8%) had PSA decreases of > or = 75%. Toxicity was chiefly hematologic with 66% of patients experiencing Grade 3 or 4 granulocytopenia. Thirty-nine percent of cycles required a delay to allow for hematologic recovery and ten patients required red cell transfusions. Non-hematologic toxicity, mainly nausea and alopecia, was mild. Topotecan administered at this dose and schedule has limited activity in patients with HRPC. Further trials of topo I inhibition in HRPC should utilize alternative schedules of topotecan (e.g., prolonged infusion) or other camptothecin analogs with more potent topo I inhibitory activity.

Topotecan (SK&F 104864, hycamptamine, NSC 609699) is believed to exert its cytotoxic effects through inhibition of topoisomerase I, the activity of which recovers rapidly on removal of the drug in vitro. In vivo studies show that the activity of topotecan is schedule dependent, favoring repeated doses. Early human studies showed that topotecan (the active lactone) had a short half-life in plasma. To prolong drug exposure, we administered topotecan as a 24-h i.v. infusion and repeated it weekly. We treated 32 patients with doses of 1.0-2.0 mg/m2. Median performance status was 1, and all but four patients had received prior chemotherapy. Dose-limiting neutropenia occurred at doses > or = 1.75 mg/m2; nadirs were observed after 1-3 doses. The recommended phase II dose is 1.5 mg/m2/week. One patient with metastatic colon cancer had a partial response. Both plasma topotecan (lactone) and total topotecan (measured by converting the hydroxyacid form to the lactone by acidification of the sample) were measured by high-performance liquid chromatography in 21 patients. During infusion, mean topotecan plasma steady-state concentrations ranged from 4.7-11.4 nM. Plasma elimination was best fit to a one-compartment model with a mean t1/2 of 3.5 h. The mean total body clearance was 388 ml/min/m2. Concentrations of the inactive form approximated those of the lactone throughout. No evidence for dose-dependent pharmacokinetics was observed in this dose range. Pharmacodynamic analysis, using the sigmoid Emax model, revealed that the pharmacokinetic parameters of both lactone and total drug were positively correlated with bone marrow toxicity. Total drug steady-state plasma concentration provided a good estimate of neutropenia, suggesting a simple, easily monitored, pharmacokinetic parameter for adaptive dosing using this schedule. Phase II evaluation of this weekly schedule is indicated in solid tumors.

CI-973, a platinum(II) derivative with a 2-methyl-1,4-butanediamine carrier ligand, has activity in cisplatin-resistant tumor models in vitro and in vivo. In a Phase I pharmacokinetic study, 31 patients were treated with CI-973 (24 to 50 mg/m2/day for 5 days; 28-day cycles) given i.v. over 30 min without routine antiemetic prophylaxis or hydration. Of the 29 patients evaluable for maximum tolerated dose determination, most had a performance status of 0 or 1, and most had received prior chemotherapy. Neutropenia was dose limiting at 40 and 50 mg/m2/day. Recovery from neutropenia was generally rapid with nadir counts and recovery usually occurring by Days 15 and 22, respectively. Drug-associated thrombocytopenia was uncommon and never severe, even in patients with Grade 4 neutropenia. Anemia was common, but did not appear dose related. Drug-related nausea and vomiting and changes in renal function were relatively infrequent and mild. No clinically evident ototoxicity was reported, although changes in audiograms were noted in several patients. CI-973 concentrations were measured in plasma ultrafiltrate and urine by high-pressure liquid chromatography. The harmonic mean terminal half-life was 2.0 h. The mean CI-973 renal and nonrenal clearance values were 42.3 and 37.4 ml/min/m2, respectively. The mean recovery of CI-973 in urine was 53% of the administered dose. The mean ratio of CI-973 renal clearance to creatinine clearance was 0.92. Total clearance correlated with creatinine clearance (r2 = 0.63). A relationship between toxicity, expressed as the percentage of reduction in absolute granulocyte count, and area under the CI-973 plasma concentration-time curve was found in a subgroup of "good-risk" patients. This relationship, described well by a sigmoidal Emax pharmacodynamic model, did not hold for patients with extensive prior therapy or poor performance status. A model for toxicity prediction based on dose and creatinine clearance has been derived and will be validated in future studies. The recommended Phase II dose of CI-973 is 30 mg/m2/day for 5 days.

A variety of cell biological, pharmacological, crystallographic and clinical approaches have indicated that the antimitotic drug estramustine has interesting and unusual properties. Although designed as an alkylating agent, the marked stability of the carbamate linkage to the steroid carrier molecule prevents the formation of alkylating intermediates. The affinity of the parent molecule for microtubule associated proteins and the concomitant antimicrotubule activity have cytotoxic consequences in tumor cells. Both preclinical and clinical studies of estramustine in combination with other antimicrotubule agents have shown that this approach has great potential to achieve therapeutic advantage, especially in disease states such as hormone refractory prostate cancer.

The addition of the antifol methotrexate to cisplatin (DDP) produces supraadditive antitumor effects in preclinical studies, but in the clinic this combination of two nephrotoxic drugs is limited by excessive toxicity. Trimetrexate (TMTX) is a second generation antifol with predominantly nonrenal elimination and antitumor activity superior to that of methotrexate in preclinical models. In early clinical trials TMTX demonstrated promising activity in non-small cell lung cancer, and nephrotoxicity was rare. We performed a Phase I clinical and pharmacological study of TMTX (escalating doses) in combination with DDP (20 mg/m2), both administered i.v. for 5 consecutive days, every 4 wk. The pharmacokinetics of TMTX was determined in 15 patients after administration of the single agent (baseline study) and following the Day 1 and Day 5 doses in the TMTX-DDP combination. The recommended Phase II single-agent dose of TMTX on this schedule, 8 mg/m2, did not produce excessive toxicity when given concurrently with DDP. Significant drug-related nephrotoxicity was not observed, even in patients receiving multiple courses of TMTX-DDP. The mean renal clearance of TMTX increased 1.4-fold and 2.8-fold over baseline on Days 1 and 5, respectively, of TMTX-DDP. Urinary flow was similarly greater on days of TMTX-DDP treatment. The nonrenal clearance of TMTX was unaffected by concurrent DDP. The steady-state volume of distribution, Vdss, and terminal elimination half-life were significantly greater on Day 5 of TMTX-DDP compared to baseline. The plasma protein-binding of TMTX in vitro was not altered by DDP, and the disappearance of ultrafilterable DDP from normal plasma in vitro was unchanged by TMTX. Although a protein-binding interaction of TMTX and DDP was not detected in normal plasma in vitro, the changes in renal clearance, Vdss, and the terminal half-life were consistent with a greater fraction of unbound TMTX in plasma following Day 5 of TMTX-DDP. Effects of DDP on the binding of TMTX to extravascular tissue components, or on the renal handling of TMTX, cannot be excluded. The increase in TMTX renal clearance correlated with increased urinary flow, which may improve the therapeutic index of TMTX as both an antineoplastic and antiparasitic agent.

Amonafide, a benzisoquinoline-1,3-dione with anti-tumor activity in preclinical screens, was administered to patients with recurrent or metastatic bidimensionally measurable colorectal cancer. Fourteen patients with no prior chemotherapy for advanced disease, performance status 0-1, and normal bone marrow, renal, and hepatic function were entered. Amonafide 300 mg/m2 was administered intravenously over 1 hour daily for five consecutive days; courses were repeated every three weeks. The major side effect was neutropenia: Grade 3 or 4 toxicity occurred in 5/14 patients. Other toxicities included nausea and vomiting, flulike symptoms, fever, rash and alopecia. Three patients had stable disease, but there were no responses observed. Amonafide at this dose and schedule has no activity in the treatment of colorectal cancer.

Low-dose phosphonacetyl-L-aspartate (PALA) may potentiate both 5-fluorouracil (5-FU) incorporation into RNA and thymidylate synthase inhibition by 5-fluorodeoxyuridylate (5-FdUMP). The gastrointestinal toxicity of 5-FU is not increased by PALA administration. Exogenous leucovorin, on the other hand, which enhances thymidylate synthase inhibition, appears to increase the clinical toxicity of 5-FU in a dose-dependent manner. As a result, the clinical use of high-dose leucovorin requires a marked dose reduction of 5-FU. Extracellular leucovorin levels of 1 microM suffice to maximize the enhancement of thymidylate synthase inhibition in several models. We conducted a trial to add leucovorin to the PALA/5-FU regimen. We chose a leucovorin dose that was predicted to yield end-infusion total reduced folate concentrations of 1 microM. The major endpoint was to determine the maximum tolerated dose of 5-FU in this combination. The regimen consisted of 250 mg/m2 PALA given on day 1 and, 24 h later, escalating 5-FU doses ranging from 1,850 to 2,600 mg/m2 admixed with 50 mg/m2 leucovorin and given by 24-h infusion. Courses were repeated weekly. A total of 24 patients with a median performance status of 1 were entered at three dose levels. Diarrhea was dose-limiting; 6/13 patients had grade II or worse diarrhea at 2,600 mg/m2. Dose modification resulted in a mean dose intensity of 2,300 mg/m2 at both the 2,600- and 2,300-mg/m2 dose levels. The 2,300-mg/m2 dose is suitable for phase II testing of this regimen. Three patients (two with breast cancer and 1 with sarcoma) had a partial remission. We measured steady-state concentrations (Css) of 5-FU in 23 patients. The mean Css increased with dose from 0.738 to 1.03 micrograms/ml. Total body clearance did not vary with dose in this range. Patients with grade II or worse diarrhea had a higher mean Css (1.10 +/- 0.19) than those with grade O or I toxicity (0.835 +/- 0.25, P < 0.02). Total bioactive folates (bound and free) were measured using a biological assay. Pretreatment values ranged from 2 to 52 nM and were not predictive of toxicity. End-infusion (23-h) values were somewhat lower than predicted and ranged from 400 to 950 nM. The risk of diarrhea was positively correlated with end-infusion total folate values. In a logistic regression analysis, total folate values obtained at 23 h were a more powerful predictor of diarrhea than were 5-FU Css values.(ABSTRACT TRUNCATED AT 400 WORDS) [ABSTRACT FROM AUTHOR]

Based on the synergy of sequential methotrexate (MTX) and 5-fluorouracil (5-FU) in vitro and in vivo and the superior antitumor activity of trimetrexate (TMTX) compared with MTX in preclinical models, we carried out a phase I trial of TMTX and 5-FU (fixed dose, 400 mg/m2 per day), both given as 10-min i.v. infusions daily x 5 days, every 28 days. The TMTX dose was escalated from 3.0 to 14.0 mg/m2 per day. In all, 92 evaluable courses were given to 34 patients, half of whom were heavily pretreated with radiation or cytotoxics. Myelosuppression and mucositis were the dose-limiting toxicities but were not different in heavily or minimally pretreated patients; there were five episodes of moderate to severe mucositis. Rash, fatigue, and diarrhea were mild toxicities. Plasma TMTX elimination was biexponential, with a mean t.1/2 alpha of 0.23 h and a t.1/2 beta of 16.7 h. The area under the plasma TMTX concentration versus time curve increased linearly with dose, suggesting first-order elimination. Total plasma TMTX clearance (mean +/- SD) was 14.3 +/- 5.9 ml/min per m2. Renal clearance accounted for approximately 7% of total clearance, indicating biotransformation as the major route of elimination. TMTX was highly protein-bound (97%). Thus, TMTX can be given with 5-FU (400 mg/m2) on a daily x 5-day bolus schedule at the 12 mg/m2 per day dose level, which was the recommended dose of TMTX as a single agent for phase II studies using the 5-day bolus schedule. [ABSTRACT FROM AUTHOR]