Effect of subacute ibuprofen dosing on rectal mucosal prostaglandin E2 levels in healthy subjects with a history of resected polyps.

Nonsteroidal antiinflammatory drugs are among the most promising chemopreventive agents for colorectal cancer. Although the mechanism by which nonsteroidal antiinflammatory drugs exert such effects remains to be further characterized, their best known pharmacological effect is inhibition of prostaglandin synthetase, which leads to decreases in tissue prostaglandin levels. We conducted a randomized, double-blind, controlled study to examine the effect of daily ibuprofen treatment on the rectal mucosal prostaglandin E2 (PGE2) levels in healthy subjects with a history of resected polyps. Study participants (n = 27) completed a 2-week run-in period and were then randomized to take a single, daily dose of ibuprofen (300 or 600 mg) or of a placebo for 4 weeks. Rectal biopsy specimens were taken before and after the run-in period and at 2 and 4 weeks after the ibuprofen/placebo treatment. Notably large between- and within-subject variability in the rectal mucosal PGE2 content was seen. The changes in PGE2 levels after ibuprofen/placebo treatment correlated with the baseline PGE2 content. After adjustment of the baseline values, 2 weeks of 300 mg/day of ibuprofen treatment resulted in significantly more suppression of PGE2 levels than that observed after the placebo treatment (55% versus 22% suppression from baseline; P = 0.033). Although other ibuprofen treatment schedules and doses appeared to result in suppression in the PGE2 levels, the suppression was not statistically significant because of the large variability in this measurement. Because lower doses are associated with fewer adverse effects, a dose of 300 mg of ibuprofen/day should be considered for future Phase II chemoprevention studies. Stratifying study participants, based on their baseline PGE2 levels and inclusion of a larger number of study subjects, are recommended for future trials where the rectal mucosal PGE2 level is to be used as a surrogate end point biomarker.

Design and baseline characteristics of study participants in the Wheat Bran Fiber trial.

The Wheat Bran Fiber (WBF) trial is a Phase III clinical trial designed to assess the effect of a WBF intervention for 3 years on the recurrence of adenomatous polyps. Men and women, 40-80 years of age, who had removal of one or more colorectal adenoma(s) 3 mm or larger within 3 months prior to study entry were recruited from three sites in the Phoenix metropolitan area. After meeting eligibility criteria, 1509 individuals entered a 6-week run-in period, consisting of a low WBF (2 g/day) intervention. Participants (n = 1429) successfully completed this phase and were randomized to a high (13.5 g/day) or low (2 g/day) WBF intervention. Various data and specimens were collected at baseline and throughout the intervention phase, which included dietary intake, physical activity, other risk factor information, blood specimens, rectal biopsies, and polyp tissues. The study design called for a colonoscopy at approximately 1 year after the qualifying colonoscopy; thus, the period between the first year and the final colonoscopy will be used to assess the effect of the intervention, which is expected to be completed in the latter part of 1998.

The effect of wheat bran fiber and calcium supplementation on rectal mucosal proliferation rates in patients with resected adenomatous colorectal polyps.

Colorectal cancers continue as the second most common cause of death from cancer in the United States. Only a few prospective, randomized clinical trials have been performed to evaluate the potential preventive effects of dietary fiber or calcium in patients with an increased risk for the development or recurrence of colorectal cancer. We designed and conducted a double-blinded, placebo-controlled randomized trial involving supplementation of fiber and calcium intake and measurements of [3H]thymidine labeling index (LI) percentages in rectal mucosal biopsies obtained from patients with resected colorectal adenomas to examine the potential mechanisms by which dietary interventions might reduce colorectal cancer risk. We performed a randomized, double-blinded, Phase II study, using a factorial design to measure the effects of supplemental dietary wheat bran fiber (2.0 or 13.5 g/day) and calcium carbonate (250 or 1500 mg/day elemental calcium) supplementation on [3H]thymidine LI percentages in rectal mucosal crypts and 24-h in vitro outgrowth cultures. Measurements were made at baseline randomization (i.e., after a 3-month placebo run-in period using 2.0 g of wheat bran fiber plus 250 mg of calcium carbonate) and after 3 and 9 months on treatment in 100 randomized participants who had a history of colon adenoma resection. Neither the wheat bran fiber nor the calcium carbonate supplements significantly reduced [3H]thymidine LI percentages in rectal mucosal crypts (total or compartmental analysis) or 24-h in vitro outgrowth cultures at either 3 or 9 months of daily supplementation in the 93 evaluable participants. We conclude that 9 months of high-dose wheat bran fiber and calcium carbonate supplementation in study participants with a history of recently resected colorectal adenomas does not have a significant effect on cellular proliferation rates in rectal mucosal biopsies, comparing 3- and 9-month results to baseline results. Ultimately, there is great need for the evaluation of these two different nutrient interventions in the setting of Phase III studies wherein adenomatous polyp recurrence, rather than a rectal mucosal biomarker, serves as the primary end point.

A phase II evaluation of esorubicin in ovarian cancer. A Southwest Oncology Group study.

Patients with a pathologically confirmed diagnosis of metastatic or advanced epithelial-type ovarian carcinoma were entered into a Phase II trial of esorubicin. Eligibility criteria included measurable disease; performance status (SWOG) 0-2; no more than one prior chemotherapeutic regimen; and no prior doxorubicin therapy. The starting esorubicin dosing schedule was 30 mg/m2 every 3 weeks for good risk patients and 25 mg/m2 every 3 weeks for poor risk patients. Twenty-one patients were eligible for evaluation of response and toxicity to treatment. These patients received a median of 3 courses of esorubicin (range 1-13 courses). None of the 21 patients experienced a response to esorubicin. Median survival was 5.5 months. Leukopenia was the major toxicity. Eleven (79%) of the good risk patients and 2 (29%) of the poor risk patients experienced severe to life-threatening leukopenia. Mild to severe anemia was seen in 10 (71%) of the good risk patients and 7 (100%) of the poor risk patients. We conclude that esorubicin is ineffective in the treatment of ovarian cancer patients who have received primary chemotherapy.

Lack of ranitidine effects on cyclophosphamide bone marrow toxicity or metabolism: a placebo-controlled clinical trial.

We previously reported that cimetidine but not ranitidine significantly enhances cyclophosphamide-induced bone marrow toxic effects and the appearance of cyclophosphamide alkylating species in a murine leukemia mouse model, and we advised caution in the use of cimetidine with microsomally metabolized anticancer drugs. Both drugs have been used for the treatment of gastric complications of chemotherapy. Using a randomized, double-blind, crossover study design, we have now evaluated the potential interaction of ranitidine with cyclophosphamide in seven cancer patients, who received two courses of cyclophosphamide, one with ranitidine and one with placebo. Four patients received ranitidine in the first course, and three received placebo. Ranitidine or placebo was started 3 days before a single dose of cyclophosphamide and given for 17 consecutive days. Ranitidine or placebo was given orally (300 mg/d), and cyclophosphamide (600 mg/m2) was given intravenously with [3H]cyclophosphamide (1000 muCi). Cyclophosphamide treatment was repeated at 4 weeks plus or minus 4 days. Blood samples were collected at intervals from 5 minutes to 24 hours after cyclophosphamide treatment and analyzed by thin-layer chromatography and radioassay for the drug and its metabolites. On days 0, 7, 14, and 21 after cyclophosphamide administration, complete blood cell counts, white blood cell differential counts, platelet counts, and SMA-17 were determined. The differences in mean nadir white blood cell counts, granulocyte counts, hemoglobin levels, and hematocrit values during ranitidine versus placebo treatment were not statistically significant. In a statistical but not a clinical sense, mean nadir platelet counts were significantly lower with ranitidine. There was a statistically significant increase in area under the curve for drug concentration in plasma x time (AUC) with ranitidine as well as a statistically significant decrease in the total-body clearance rate of the cyclophosphamide molecule. However, the effect on AUC for the major oncolytic metabolites 4-hydroxycyclophosphamide and phosphoramide mustard was not statistically significant. The lack of toxicologic or metabolic interaction between ranitidine and cyclophosphamide suggests that ranitidine can be used safely with cyclophosphamide.

Cisplatin in advanced cancer of the cervix: an update.

Cisplatin is the single most active cytotoxic agent in the treatment of patients with recurrent or metastatic squamous cell cancer of the cervix; no other standard drug has been associated consistently with objective response rates of 25% or higher. However, cervical cancer is a relatively drug-resistant disease and prolonged cisplatin treatment appears to induce multiple mechanisms of tumor resistance. The majority of objective responses to cisplatin are partial and relatively short-lived and, therefore, have little impact on survival duration. Complete responses to cisplatin are seen predominantly in patients with extrapelvic metastases rather than pelvic recurrences. This article examines the role of cisplatin in the management of advanced cervical cancer with emphasis on its efficacy in the following circumstances: as a single agent; in combination with other cytotoxic drugs; in previously treated patients; and when administered before surgery or before or concurrent with definitive radiation therapy.

Carboplatin in the first-line chemotherapy of ovarian cancer.

When used as first-line treatment for advanced ovarian cancer in phase III trials, single-agent carboplatin has produced clinical complete response rates comparable with or exceeding those of single-agent cisplatin. Phase I/II trials of combination chemotherapy have yielded overall objective response rates of 44% to 75% when carboplatin was combined with either cyclophosphamide or chlorambucil. In randomized phase III trials of carboplatin combination chemotherapy, response rates similar to those of cisplatin combinations have been achieved but with greatly reduced toxicities. The data from these phase I, II, and III trials show that carboplatin is as active as cisplatin in patients with advanced ovarian cancer and is associated with a significantly lower incidence and is associated with a significantly lower incidence of emesis, ototoxicity, peripheral neuropathy, and renal dysfunction. Thus, carboplatin should be considered the platinum compound of choice in the firstline treatment of advanced ovarian cancer.

The role of cisplatin in the management of advanced squamous cell cancer of the cervix.

Cisplatin has emerged as the most active agent in the treatment of patients with advanced cervical cancer. While no other standard cytotoxic agent has been associated consistently with objective response rates in excess of 20%, single-agent cisplatin has produced clinical complete response (CR) rates of up to 33% in previously untreated patients. The results of over 25 phase II cisplatin combination chemotherapy trials show overall objective response and clinical CR rates ranging to 65% and 36%, respectively. However, patient survival durations in these studies (median range, 4 to 10.5 months) appear similar to those observed in patients treated with single-agent cisplatin, suggesting that cisplatin activity is not enhanced by the addition of other agents in the treatment of this disease. Cisplatin's documented radiopotentiating effects have led to more than 20 phase II pilot studies of cisplatin-based regimens before or concurrent with definitive radiation therapy to the pelvis for advanced, previously untreated disease. The overall objective response rates to preradiation chemotherapy in these studies range from 31% to 100%; however, survival durations do not appear prolonged. In contrast, patients who received concurrent pelvic irradiation and cisplatin-based chemotherapy survived between 12+ and 36+ months. These encouraging results have led to phase III trials of this combined-modality approach that may irrevocably change the management of patients with previously untreated, advanced cervical cancer.

Carboplatin in the treatment of ovarian cancer.

Carboplatin, a new cisplatin analogue, appears as active as cisplatin in patients with advanced ovarian cancer, but in phase I and II trials has proven significantly less toxic. In single-agent phase II trials, carboplatin has been associated with clinical complete response (CR) rates of up to 13% and overall objective response rates of up to 32% in patients with prior cisplatin exposure. As first-line treatment in phase II trials, single-agent carboplatin has produced clinical CR rates ranging from 9% to 62% and overall objective response rates of 45% to 85%. In phase III trials in this patient population, single-agent carboplatin has been associated with clinical CR rates comparable with or exceeding those of single-agent cisplatin. Phase I/II trials of combination chemotherapy have yielded overall objective response rates of 44% to 75% when carboplatin was combined with either cyclophosphamide or chlorambucil. In randomized phase III trials of combination chemotherapy, response rates similar to those of cisplatin have been achieved. However, toxicities were greatly reduced in the carboplatin-treated patients. The data from these phase I, II, and III trials document that carboplatin is as active as cisplatin in patients with advanced ovarian cancer and is associated with a significantly lower incidence of emesis, ototoxicity, peripheral neuropathy, and renal dysfunction. Thus, carboplatin may become the platinum compound of choice in the first-line treatment of advanced ovarian cancer.

Randomized phase III trial of chemoimmunotherapy in patients with previously untreated stage III, optimal disease ovarian cancer: a Southwest Oncology Group Study.

Between 1979 and 1984, 98 patients considered to have stage III epithelial type ovarian cancer and optimal surgical resections (i.e., less than 2 cm residual tumor masses) were randomly assigned to treatment with 2 cm residual tumor masses) were randomly assigned to treatment with doxorubicin + cyclophosphamide + BCG (DC + BCG) vs doxorubicin + cyclophosphamide + cisplatin (DCP) vs. doxorubicin + cyclophosphamide + cisplatin + BCG (DCP + BCG). Seventeen (17%) were considered ineligible on the basis of formal histopathologic review. The pathologically proven complete response rates for DC + BCG, DCP, and DCP + BCG-treated patients were 20, 23, and 41%, respectively, and the median survival durations were 36.8, 48.2, and 57.4 months, respectively. Because of the relatively small sample size, definite conclusions concerning the response or survival impact of adding cisplatin to DC + BCG or BCG to DCP can not be drawn; nevertheless, all three groups of patients experienced prolonged survival durations with approximately 40% of all eligible patients alive at 5 years.

Randomized phase III trial of chemoimmunotherapy in patients with previously untreated stages III and IV suboptimal disease ovarian cancer: a Southwest Oncology Group Study.

Between 1979 and 1984, 185 fully evaluable patients with stage III or IV epithelial type ovarian cancer and suboptimal surgical resections were randomly assigned to treatment with doxorubicin + cyclophosphamide + BCG (DC + BCG) vs doxorubicin + cyclophosphamide + cisplatin (DCP) vs. doxorubicin + cyclophosphamide + cisplatin + BCG (DCP + BCG). Patients with measurable disease (119) were analyzed separately from those with nonmeasurable disease (66). In measurable disease patients the overall clinical complete plus partial response rates for DC + BCG, DCP, and DCP + BCG-treated patients were 36, 57, and 59%, respectively. Although there were no significant patient characteristic differences between the DCP and DCP + BCG treatment groups, the addition of cisplatin to the DC + BCG regimen resulted in significantly prolonged response (P less than 0.03) and survival (P less than 0.002) durations. To the contrary, the addition of BCG to the DCP regimen did not improve objective response rates or response or survival durations. For patients with nonmeasurable, suboptimal disease there were no significant differences between the three treatments with respect to response or survival parameters; however, patients in this disease category fared generally better than those with clinically measurable disease. We conclude that cisplatin adds significantly to the efficacy of DC + BCG, but BCG does not add to the efficacy of DCP in patients with measurable, stage III or IV disease.

Experimental dacarbazine antitumor activity and skin toxicity in relation to light exposure and pharmacologic antidotes.

Decarbazine (DTIC) is reported to exhibit enhanced clinical toxicity and increased antitumor activity in vitro when exposed to light. Since it was unclear whether light exposure enhanced DTIC antitumor activity or local toxic effects in vivo, a series of experiments was performed in mice given DTIC solutions exposed to light for 2 hours at room temperature. Adenocarcinoma 07/A was implanted by trocar in adult female BALB/c mice. DTIC (50 and 100 mg/kg) was given ip three times per week for 2 weeks. Both drug doses significantly inhibited tumor growth. However, there was no significant difference between light-exposed and -protected drug treatments. In vitro clonogenic assays in L1210 leukemia and Chinese hamster ovary (CHO) cells demonstrated that DTIC cytotoxicity was not increased with light exposure (0.8 J/m2/sec). Both cell lines showed a dose-response relationship to DTIC after 1- or 6-hour exposures in the presence or absence of light. Normal dehaired BALB/c mice were given single intradermal injections of 0.5, 1.75, 5.0, or 10 mg of DTIC in 0.05 ml of saline. Dose-dependent skin ulceration was produced at the 1.75-, 5.0-, and 10.0-mg dose levels. Again, there was no consistent statistical difference in skin ulceration between treatments using light-exposed and -protected DTIC vials. However, when mice were exposed to light following intradermal DTIC, increased skin toxicity was produced (P less than 0.05 by Student-Neuman-Keuls multiple range test). A number of potential local antidotes to DTIC skin ulceration were found to be ineffective. These included: L-cysteine, dimethyl sulfoxide, hyaluronidase, hydrocortisone, and 0.9% saline. Sodium thiosulfate (0.3 M) significantly reduced DTIC skin ulcers as did pre-exposure of DTIC to S-9 rat liver enzymes and NADPH. Neither mild skin heating nor cooling reduced DTIC ulcerations. DTIC appears to synergize with light in vivo to produce increased toxicity. Patients receiving DTIC should avoid intense light exposure after drug injection. However, elaborate precautions to prevent light exposure of DTIC solutions during preparation or injection appear to be unnecessary.

Phase II evaluation of bisantrene hydrochloride in refractory malignant melanoma. A Southwest Oncology Group Study.

Patients with a pathologically proven diagnosis of malignant melanoma were entered into a phase II trial of bisantrene. Eligibility criteria included: measurable, metastatic disease; performance status 0-2 SWOG; and adriamycin total cumulative dose of less than 400 mg/m2. The initial bisantrene dosing schedule was 260 mg/m2 every three weeks for good risk patients. Due to the absence of an objective response and the lack of severe toxicity in the first 25 bisantrene treated patients, the starting dose was increased to 300 mg/m2 for good risk patients. Fifty-one patients received a median of two bisantrene courses (range 1-11 courses). Leukopenia was the major toxicity. Fifteen (68%) of the 22 good risk, intermediate dose patients (260 mg/m2), and 8 (80%) of the 10 good risk, high dose patients (300 mg/m2) evaluable for toxicity experienced mild-severe leukopenia. None of the 51 patients experienced a complete or partial response to bisantrene. Median survival was 3.3 months. We conclude that bisantrene is ineffective in the treatment of metastatic melanoma.