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Biomedical subjects

C G Leichman

Publications and source records attributed to C G Leichman.

35 records · Page 2Linked to original sources
PubMed1996

Phase I and pharmacokinetic study of oral UFT, a combination of the 5-fluorouracil prodrug tegafur and uracil.

UFT is an oral preparation combining the 5-fluorouracil (FU) prodrug tegafur (FT) and uracil (U) in a 1:4 ratio, which is commercially available in Japan for the treatment of breast and gastrointestinal cancers. We sought to determine the tolerance of daily oral UFT and to relate this tolerance to the pharmacokinetics of FT and/or the derived FU, while exploring the possibility of circadian FU kinetics contributing to the results. A 28-day schedule followed by 2 weeks rest was began at the initial level of 300 mg/m2/day administered either at 8 a.m. or at 6 p.m. At the following level, 400 mg/m2/day patients were randomly assigned to a split-dose administration or to the above single, timed dose administration. Intolerance to single dosing was clearly demonstrated, and only the split dosing was advanced to 500 mg/m2/day. When this level proved too toxic, 400 mg/m2 was studied further on a 7 a.m., 3 p.m., and 11 p.m. (every 8 h) schedule. Pharmacology was determined on selected patients. In the single dose administration, areas under the curves of FU were higher following p.m. dosing, although substantial interpatient variation was present. Toxicities (diarrhea and neutropenia) were more severe in patients receiving the drug in single daily doses. We conclude that the kinetics of FT are saturable, with disproportionate increases in area under the curve (and toxicities) as dose levels are increased. With divided dosing, tolerance improves. UFT at a dose of 400 mg/m2/day administered as three divided doses (every 8 h) is suitable for Phase II studies, although toxicity requiring cessation of drug administration prior to completion of 28-day cycles will occur in some patients.

Administration, Oral↗
PubMed1995

Thymidylate synthase gene and protein expression correlate and are associated with response to 5-fluorouracil in human colorectal and gastric tumors.

Thymidylate synthase (TS) is the target enzyme for 5-fluorouracil (5-FU). We have correlated TS protein and gene expression with the response in patients with colorectal (n = 9) and gastric cancer (n = 12) treated with infusional 5-FU plus leucovorin (LV) or infusional 5-FU/LV and cisplatin, respectively. TS protein expression was analyzed by Western blot using TS106 monoclonal antibody and densitometry scanning. TS gene expression was measured by PCR analysis using beta-actin as an internal standard and expressed as a TS:beta-actin mRNA ratio. A close linear relationship was noted between TS protein expression and TS gene expression (r2 = 0.60) for the 21 tumor samples analyzed. TS immunohistochemical staining on 15 of the 21 samples revealed that the TS staining intensity correlated closely with TS protein and mRNA expression. In two biopsy samples, TS protein levels and TS gene expression did not correlate; however, one of these exhibited a focal TS staining pattern. Both the TS protein level and TS gene expression were significantly associated with response to 5-FU-based therapy. Patients with responsive disease had a mean TS protein level of 0.17 +/- 0.03 arbitrary units (range, 0.05 to 0.38), whereas in patients whose tumors did not respond, the mean TS protein level was significantly higher 0.60 +/- 0.09 (range, 0.06 to 1.01; P < 0.01). A similar pattern was noted with TS gene expression. In patients with responsive disease, the mean TS:beta-actin gene ratio was 1.36 +/- 0.3 (range, 0.5-3.3 x 10(-3). In contrast, biopsies from patients with unresponsive disease had a mean TS:beta-actin gene ratio of 15.4 +/- 2.6 x 10(-3) (range, 2.7-35.9; P < 0.01). TS protein and TS mRNA expression are highly correlated, and each predict for response to 5-FU/LV-based chemotherapy in patients with colorectal and gastric cancer.

Actins↗
PubMed1995

A fixed-ratio combination of uracil and Ftorafur (UFT) with low dose leucovorin. An active oral regimen for advanced colorectal cancer.

BACKGROUND: UFT is a fixed-ratio combination of uracil and Ftorafur, a prodrug that is absorbed orally and metabolized in vivo to 5-fluorouracil (5-FU). Uracil potentiates 5-FU through interference with its catabolism. The combination of UFT and leucovorin in patients with advanced incurable colorectal cancer, to evaluate preliminary activity and toxicity in this patient population. METHODS: Twenty-one patients were treated. Twenty patients were evaluable for toxicity and response. Patients received UFT 350 mg/m2/day divided every 8 hours. Patients took a 5 mg tablet of leucovorin every 8 hours, concurrent with each UFT dose. Treatment was continued for 28 consecutive days, followed by a 7-day rest. RESULTS: Five major objective responses (one complete and four partial) were observed. Toxicity was mild, with no dose-limiting myelosuppression. Four patients experienced grade 3 diarrhea or higher, and two patients experienced dose-limiting mucositis. CONCLUSION: UFT and low dose leucovorin is a well tolerated, orally administered regimen with activity in colorectal cancer. A randomized comparison of this regimen with conventional parenteral regimens is warranted.

Administration, Oral↗
PubMed1995

Intraperitoneal 5-fluoro-2'-deoxyuridine (FUDR) and (S)-leucovorin for disease predominantly confined to the peritoneal cavity: a pharmacokinetic and toxicity study.

Intraperitoneal (IP) administration of fluorinated pyrimidines has been evaluated for ovarian and gastrointestinal malignancies in phase I, II, and III trials. The tolerance and pharmacokinetic profile of IP 5-fluoro-2'-deoxyuridine(FUDR) alone and with (R,S)-leucovorin ((R,S)-LV) have each been evaluated in previous phase I studies. FUDR doses of 3 g per day with and without (R,S)-LV doses up to 640 mg per day given IP are well tolerated. The current phase I study was designed to determine the pharmacokinetic profiles and clinical tolerance of escalating doses of the pure biologically active S-isomer of leucovorin ((S)-LV) given IP with the same dosing schedule of FUDR. A group of 16 patients with disease confined to the abdominal cavity were treated in this study. Pharmacokinetic studies of blood and peritoneal fluid, toxicity profiles, and clinical response for the first three cycles are reported here. The toxicity profile did not significantly differ from the prior two studies. All non-hematologic toxicities, such as fatigue, nausea, vomiting, diarrhea, and abdominal discomfort were less than grade 4, and most were less than grade 3. Neutropenia and thrombocytopenia were uncommon and observed only in patients with compromised bone marrow reserve. The pharmacokinetic profiles were also congruent with the previous studies and indicate a three-log advantage for FUDR. The (S)-LV profiles in the peritoneal cavity paralleled those of FUDR. Antitumor effects or absence of progression until after cessation of therapy were documented in 11 patients. At a median follow-up of 18 months 44% of patients were alive. IP administration of 3-g of FUDR and up to 640 mg (S)-LV daily for three days was well tolerated. The tolerance and antitumor effects observed during IP FUDR and LV in these studies encourage further exploration of this regimen against ovarian and gastrointestinal malignancies. The actual role and optimal dose of LV as an enhancer of the antitumor actions of FUDR administered by this route remain unknown.

Adult↗
PubMed1995

Phase II study of fluorouracil and its modulation in advanced colorectal cancer: a Southwest Oncology Group study.

PURPOSE: A variety of fluorinated pyrimidine-based regimens for the treatment of disseminated colorectal cancer have been presented in the medical literature. The Southwest Oncology Group designed a screening trial of seven regimens of fluorouracil (5-FU) to assess efficacy and toxicity afforded by biochemical modulation or schedule variations. PATIENTS AND METHODS: Six hundred twenty patients were entered into this trial between August 1989 and January 1993. Eligible patients were classified as having recurrent or disseminated disease that was measurable or nonmeasurable. All eligible patients were evaluated for toxicity and survival; patients with measurable disease were evaluated for response according to standard criteria. RESULTS: No regimen achieved a higher response rate than single-agent bolus 5-FU. Eighty-four percent of patients have been monitored until death. The median survival time for the entire cohort is 14 months. Survival hazards ratios showed a positive trend in favor of the unmodulated infusion regimens, while high-grade toxicities occurred more frequently in the 5-FU bolus arms. The major high-grade toxicities were granulocytopenia and diarrhea. CONCLUSION: In this trial, no regimen provided substantial improvement relative to 5-FU bolus or single-agent therapy for either response or survival in the treatment of disseminated colorectal cancer. The single-agent infusion regimens demonstrated the most encouraging results with a favorable toxicity profile and a 2-month longer survival duration than 5-FU bolus therapy.

Adult↗
PubMed1994

Intraperitoneal 5-fluoro-2'-deoxyuridine with escalating doses of leucovorin: pharmacology and clinical tolerance.

In a preceding study, we established the tolerance and pharmacokinetic behavior of 5-fluoro-2'-deoxyuridine (FdUrd) given by the intraperitoneal (IP) route. A dose of 3 g daily x 3 days was found satisfactory for Phase II study and exploration of biochemical modulation. Therefore, the current study was conducted to study the tolerance and pharmacokinetics of such a dose-schedule and route of FdUrd combined with escalating doses of leucovorin (LV). Fourteen patients were entered and 13 were evaluable for tolerance determination. Pharmacologic determinations of IP FdUrd and 5-Fluorouracil (FUra) derived from it and LV were obtained by HPLC methods on 11 occasions. Findings were compared with the preceding study of FdUrd alone. LV did not appear to alter the tolerance of IP FdUrd even in the four patients receiving the highest dose of LV (640 mg). Toxicities included nausea, vomiting, and rarely neutropenia and diarrhea. Pharmacokinetic parameters indicate a parallel rate of egress of FdUrd and LV from the peritoneal cavity. The pharmacologic advantage for FdUrd is at least 3 logs as previously reported and one log for LV. Evidence of antitumor effect was noted particularly among untreated patients with gastrointestinal primaries. We conclude that IP FdUrd 3 g and LV in doses of up to 640 mg x 3 days are well tolerated. Since FdUrd is more potent, has an even greater hepatic clearance and shows greater potential for modulation with LV than FUra, it may be the preferred fluoropyrimidine for subsequent studies via the IP route in the treatment of carcinomas with prominent peritoneal spread. The pharmacologic advantage for leucovorin is limited but it is a good marker for peritoneal clearance since it parallels FdUrd clearance.

Abdominal Neoplasms↗
PubMed1993

Phase I study of (6R)-5,10-dideazatetrahydrofolate: a folate antimetabolite inhibitory to de novo purine synthesis.

BACKGROUND: Cancer chemotherapy with folate antimetabolites has been traditionally targeted at the enzyme dihydrofolate reductase and is based on the requirement of dividing tumor cells for a supply of thymidylate and purines. However, a new compound, 5,10-dideazatetrahydrofolate (DDATHF, whose 6R diastereomer is also known as Lometrexol), has become available that prevents tumor cell growth by inhibiting the first of the folate-dependent enzymes involved in de novo purine synthesis, glycinamide ribonucleotide formyltransferase. PURPOSE: We investigated the toxicity and therapeutic activity of DDATHF in a phase I clinical trial. METHODS: DDATHF was given at one of the following dose levels to 33 patients (16 females and 17 males) with malignant solid tumors: 3.0 mg/m2 per week (level A) to 10 patients, 4.5 mg/m2 per week (level B) to 13 patients, or 6.0 mg/m2 per week (level C) to 10 patients. Each drug cycle consisted of three weekly injections of DDATHF followed by a 2-week rest prior to redosing in the next cycle. RESULTS: Of 33 patients, 27 received at least one full cycle of DDATHF. Thrombocytopenia was the major dose-limiting toxicity, and it was severe in one of 10 patients during the first cycle and in two of four patients during the second cycle. Because of cumulative toxicity at 6.0 mg/m2, second or later cycles were abbreviated to two weekly doses. Stomatitis was generally mild, but it was dose-limiting in one patient. Neutropenia was infrequent and mild, and normocytic anemia requiring blood transfusion was common with repeat dosing. Leucovorin was given for grade 2 or greater thrombocytopenia and resulted in hematologic recovery within 1 week in all eight patients so treated. Without leucovorin, the thrombocytopenia lasted from 7 to 49 days in three patients. A partial response was noted in one patient with non-small-cell lung cancer and a minor response in one patient with breast cancer. Three patients with colorectal cancer achieved stable disease for greater than 3 months with improvement in carcinoembryonic antigen levels in one patient. CONCLUSIONS: DDATHF has an unusual pattern of toxicity with repetitive dosing, and humans with advanced cancer are considerably more sensitive than would be predicted from previous animal studies. Although doses of 6.0 mg/m2 per week on our schedule have been determined to be safe, repeated cycles require careful monitoring because of cumulative toxic effects. IMPLICATIONS: Additional phase I studies of DDATHF that relate toxicity to folate intake and tissue folate pools appear warranted.

Adult↗
PubMed1993

Prolonged continuous infusion of fluorouracil with weekly bolus leucovorin: a phase II study in patients with disseminated colorectal cancer.

BACKGROUND: Biochemical modulation of bolus fluorouracil (5-FU) by addition of leucovorin to the treatment regimen has increased response in patients with disseminated colorectal cancer from fewer than 20% to more than 40%. In view of the short half-life of 5-FU and its cell cycle specificity, it may be that infusion rather than intravenous bolus injection would increase efficacy. Furthermore, the advent of safer indwelling intravenous catheters and pump technology, allowing home and ambulatory treatment, has made protracted infusion clinically feasible. To examine these questions, we conducted a phase I trial using protracted infusion of 5-FU by indwelling catheter and pump, with leucovorin given by bolus injection, and reported 40% partial response. PURPOSE: We have now initiated a phase II study of 5-FU given by prolonged continuous infusion with weekly bolus injections of leucovorin in previously untreated patients with measurable, disseminated colorectal cancer. METHODS: Forty-one patients were treated. The regimen consisted of treatment for 4 weeks with 5-FU at a dose of 200 mg/m2 daily as a continuous infusion by indwelling intravenous catheter and pump, followed by a 2-week rest and then by monthly cycles of 3 weeks of treatment and 1-week rest until disease progression. Leucovorin was given as a bolus injection of 20 mg/m2 at the beginning of each week of treatment with 5-FU. RESULTS: Nineteen (46%) of 41 patients had objective response: Three complete responses and 16 partial responses were seen. Overall, the median duration of response was 8 months. The median duration of survival was 16 months: 18 months for responders and 10 months for nonresponders. In general, toxic effects were mild and consisted primarily of stomatitis and palmar-plantar erythrodysesthesia (hand-foot syndrome). Neither grade 4 toxic effects nor treatment-related deaths were observed. The only serious side effects were catheter thrombosis (three patients) and catheter sepsis (one patient). CONCLUSION: We conclude that this safe regimen is one of the most effective for the treatment of disseminated colorectal cancer. IMPLICATIONS: The regimen should be tested prospectively against other regimens in use for this disease. It is currently included in a phase III study of the Southwest Oncology Group for this purpose. That study will assess quality of life as well as response rates and survival duration.

Adjuvants, Pharmaceutic↗
PubMed1992

Preoperative systemic chemotherapy followed by adjuvant postoperative intraperitoneal therapy for gastric cancer: a University of Southern California pilot program.

PURPOSE: 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 AND MATERIALS: 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. CONCLUSION: 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.

Adenocarcinoma↗
PubMed1990

Biological modification of protracted infusion of 5-fluorouracil with weekly leucovorin. A dose seeking clinical trial for patients with disseminated gastrointestinal cancers.

A clinical trial was designed to find the maximally tolerated dose of weekly leucovorin (LV) that could be combined with 4 weeks of protracted infusion (PI) of 5-fluorouracil (5FU) at a fixed dose of 200 mg/m2. A total of 36 patients with disseminated gastrointestinal malignancies were treated; 9 either progressed or died before receiving 4 weeks of treatment leaving 27 patients evaluable for toxicity and response. 5FU was given as a protracted infusion using an ambulatory infusion pump and indwelling venous access. LV doses included 20, 25, 50, and 75 mg/m2 given as an i.v. push at the time of weekly pump fill with 5FU. In all, 72% of the patients tolerated LV at 20 mg/m2 for 4 continuous weeks, whereas the higher doses required treatment rests prior to 4 weeks. The dose-limiting toxicity at all doses was stomatitis. No significant myelosuppression was seen; diarrhea was infrequent. Overall, 40% of the patients with measurable cancer had partial responses. In view of evidence of biologic and therapeutic effects of these weekly doses of 20 mg/m2 LV with 200 mg/m2 5FU per day given as a protracted infusion over 4 weeks, phase II trials and multimodality studies for patients with gastrointestinal malignancies are being initiated at our institution using this dose and schedule.

Aged↗
PubMed1987

Nonoperative therapy for squamous-cell cancer of the esophagus.

Based on the surgical pathology and survival for patients in previous trials using a neoadjuvant program of chemotherapy (5-fluorouracil [5-FU]-cisplatin) and radiation (3,000 cGy) before surgery for squamous-cell cancer (SCC) of the esophagus, a nonoperative pilot trial was designed to test if survival and recurrence would differ from our historical controls if routine esophagectomy was eliminated. Twenty patients were treated. The protocol called for the delivery of 5-FU infusion (1,000 mg/m2/d X 4 d) days 1 to 4 and 29 to 32 with cisplatin (100 mg/m2) day 1 and 29 sandwiched around external beam radiation (3,000 cGy over 3 weeks). Mitomycin C (10 mg/m2) day 57 was administered with bleomycin infusion (20 U/d X 4 d) days 57 to 60 and 78 to 81. A radiation boost of 2,000 cGy was administered 200 cGy/d days 99 to 103 and 106 to 110. Clinical pulmonary toxicity forced withdrawal of bleomycin and mitomycin C in the last four patients treated; two further courses of 5-FU-cisplatin were administered instead. The median measurement of the 20 esophageal lesions by barium swallow was 7 cm. Four patients underwent salvage surgery to prevent life-threatening aspiration pneumonia. The median survival for the 20 patients is 22 months, with a range from 6 to 39+ months. The six patients clinically without cancer are alive 22+ to 39+ months (median, 35+ months). Three patients died manifesting only local (infield) recurrence; five died manifesting only distant recurrence; and five developed local and distant recurrence. While the toxicity of the four drug regimen as administered was prohibitive, the survival and quality of survival is superior to the regimen previously used, which routinely used surgery after preoperative chemotherapy and radiation.

Aged↗
PubMed1987

Phase I study of echinomycin.

Echinomycin was administered to patients with advanced carcinoma in escalating doses ranging from 60 to 1500 micrograms/m2 given weekly by 15-minute iv infusions for four doses, with a subsequent 2-week rest period. Dose-limiting nausea, vomiting, and anorexia associated with varying degrees of renal and hepatic dysfunction proved dose-limiting at the 1500-micrograms/m2 level. Thrombocytopenia was noted in 15% of patients receiving greater than or equal to 700 micrograms/m2 and was severe in 11% without an evident dose-response relationship. Leukopenia was rare and mild when encountered. Allergic reactions were observed. Phase II trials are feasible using a dose schedule of 1200 micrograms/m2/week X 4 weeks.

Carcinoma↗
PubMedDate not supplied

Challenges posed by non-random missing quality of life data in an advanced-stage colorectal cancer clinical trial.

Effects of variations in agent, dose, and route of treatment administration on patient reported quality of life (QOL) were examined for 279 patients enrolled on a seven-arm randomized clinical trial (S8905) of 5-FU and its modulation for advanced colorectal cancer. Patients completed QOL questionnaires at randomization and weeks 6, 11, and 21 post-randomization with five QOL endpoints considered primary: three treatment-specific symptoms (stomatitis, diarrhea, and hand/foot sensitivity); physical functioning; and emotional functioning. Patient compliance with the QOL assessment schedule was good, supporting the feasibility of including QOL measures in cooperative group trials. However, death and deteriorating health produced substantial missing data. Cross-sectional analyses indicated that the seven therapeutic arms did not differ in their impact on QOL. Unfortunately, longitudinal analyses of the QOL data were inappropriate given non-random missing data. Graphical presentation of non-random missing data identified the seriousness of this problem and its effect on potential conclusions about QOL during treatment. This problem appears to be particularly challenging in the context of advanced-stage disease. Failure to recognize the presence of non-random missing data can lead to serious overestimates of patient QOL over time.

Adult↗
PubMedDate not supplied

Phase II trial of amonafide in advanced pancreas cancer. A Southwest Oncology Group study.

Amonafide is a new synthetic anticancer agent whose mechanism of action is through inhibition of macromolecular synthesis as well as DNA intercalation. The Southwest Oncology Group (SWOG) has investigated this drug in a phase II study of pancreas cancer. Thirty-six patients were registered on this study: of these 29 were eligible for response evaluation, and 20 received the two cycles required for making a response assessment. Patients met the standard phase II criteria of no prior chemotherapy, measurable disease and a SWOG performance status of 2 or less. Toxicity, predominantly hematologic with significant neutropenia and thrombocytopenia, was quite severe. Four treatment related deaths were encountered. No responses were seen in thirty-six patients studied. We conclude that this drug is not active against adenocarcinoma of the pancreas.

Adenine↗
PubMedDate not supplied

Quantitation of intratumoral thymidylate synthase expression predicts for resistance to protracted infusion of 5-fluorouracil and weekly leucovorin in disseminated colorectal cancers: preliminary report from an ongoing trial.

A clinical trial for patients with measurable, disseminated colorectal cancer is being conducted to determine: (1) if intratumoral expression of thymidylate synthase (TS) affects response to protracted-infusion 5-fluorouracil (5FU); and (2) whether intratumoral expression of TS increases when clinical resistance is found after response to 5-FU. Polymerase chain reaction technology is employed to determine TS expression. Using beta-actin as an internal standard, TS expressions for 26 patients range from 0.5 x 10(-3) to 22.6 x 10(-3). Currently, 22 patients are evaluable for response and TS quantitation of their measurable tumour. 8 patients (36%) have had partial responses; 3 responding patients had been previously treated with 5-FU. A strong statistical association between TS expression and resistance to therapy has been found (P = 0.004). No patient with TS expression of 4.0 x 10(-3) or greater has responded. On average, patients previously treated with 5-FU have slightly higher levels of TS expression in their measurable tumours (P = 0.4). Whether responding patients will develop increased expressions of TS upon clinical progression of their cancer remains to be determined. Confirmation of these results in a larger cohort could lead to a scientific rationale for deciding upon specific therapy for patients with disseminated colorectal cancers.

Adult↗