Preclinical and clinical studies of docetaxel and exisulind in the treatment of human lung cancer

Lung cancer is the leading cause of cancer death in the United States. The majority of patients with non-small cell lung cancers present with inoperable disease because of the presence of metastases to regional lymph nodes or other metastatic sites. About one third of patients have stage IV disease with metastases to distant organs at the time of diagnosis. The prognosis for these patients is very poor. With best supportive care the median survival is only 4 months and the 1-year survival rate is 10% to 15%. Current chemotherapy combinations improve the survival and quality of life for patients with advanced non-small cell lung cancer. With two-drug combinations, median survival is increased to 8 months or more and 1-year survival is increased to 35% to 40%. Still, complete response rates are low and more than 80% of patients die within 1 year of diagnosis. The improvements created by current therapies led to studies of chemotherapy in the second-line setting. Docetaxel has been shown to improve survival of patients who failed platinum-based chemotherapy and was approved by the U.S. Food and Drug Administration for therapy in this setting. However, response rates were very low and survival very short. Therefore, new therapies are urgently needed. Exisulind is a novel oral anticancer agent that holds promise for the treatment of patients with advanced non-small cell lung cancer. Exisulind was originally developed as a chemoprevention agent for colorectal cancer. Preclinical studies showed that exisulind could prevent polyp formation and inhibit the growth of colorectal cancers. Subsequent preclinical studies showed that exisulind also inhibited the growth of human breast, prostate, and lung cancers. Phase I clinical studies showed that twice-daily oral doses could be given safely and would provide peak concentrations that were equivalent to those required for in vitro effects. These observations lead to the studies of the combination of exisulind and docetaxel in preclinical and clinical studies in human lung cancer described in this article.

[Chemoprevention of colorectal cancer]

A NEW CONCEPT: Chemoprevention of cancer consists in the administration of chemical agents to prevent or inhibit carcinogenesis. This strategy can be applied at any stage of carcinogenesis.

ASSESSMENT

The development of such agents relies on classical bases: phases I, II and III. The approach consists in assessing the effect of the substance tested in patients with history of resected adenomas of the colon and at high risk of relapse and/or family risk of colon cancer.

THE PRINCIPLE AGENTS UNDER ASSESSMENT

Are aspirin, type 2 cyclo-oxygenase inhibitors, calcium, folic acid, certain vitamins, hormone replacement therapy for menopausal women and difluoromethylornithine (DFMO).

Cancer prevention with green tea and monitoring by a new biomarker, hnRNP B1

The study of green tea polyphenols as a cancer preventative is approaching a new era, with significant results accumulating rapidly. This paper briefly reviews four topics related to mechanisms of action of tea polyphenols: (I) identification of the genes commonly affected by EGCG, as demonstrated by Clontech's Atlas cDNA Expression Array; (II) the significance of heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1) as a new biomarker for early detection of lung cancer, and inhibition of its expression by EGCG; (III) the synergistic or additive effects of EGCG with the cancer preventive agents, sulindac and tamoxifen, on induction of apoptosis in PC-9 cells and on inhibition of intestinal tumor development in multiple intestinal neoplasia (Min) mice; (IV) the results of a 10 year prospective cohort study demonstrating the effectiveness of daily consumption of green tea in preventing cancer, and a prototype study for developing green tea beverage as cancer preventive.

Docetaxel and exisulind in hormone-refractory prostate cancer

Single-agent docetaxel has been shown to produce a significant decrease in prostate-specific antigen (PSA) levels among patients with hormone-refractory prostate cancer (HRPC). A recent study also showed that exisulind, a sulfone metabolite of the nonsteroidal anti-inflammatory drug sulindac, lengthens the median PSA doubling time in men who had increasing PSA levels after radical prostatectomy. Furthermore, exisulind has shown significant antineoplastic activity in prostate cancer cell lines in vitro and in nude mouse xenograft models. Because preclinical studies have suggested synergistic interactions between docetaxel and exisulind, a phase I/II clinical trial combining these agents has been initiated in patients with HRPC. The primary objective of this study is to determine PSA response and measurable disease response rate of the combination therapy; secondary objectives include toxicity assessment and determination of time to disease progression, duration of response, and overall survival. Accrual is ongoing.

Enhanced apoptosis and transforming growth factor-beta1 expression in colorectal adenomas and carcinomas after Sulindac therapy

PURPOSE

We tried to elucidate the effects of sulindac on human colorectal carcinoma.

METHODS

Sulindac (300 mg/day) was administered for two weeks before operation to 33 patients with sporadic colorectal carcinoma (Sulindac Group). Resected specimens were used to detect apoptosis by terminal dUTP nick end labeling and transforming growth factor (TGF)-beta1 expression by immunohistochemistry. The results were compared with those from the historical Control Group. Twenty-nine available preoperative biopsies taken from carcinomas before sulindac prescription and 22 concurrent colorectal adenomas (9 and 13 in Sulindac and Control Groups, respectively) in the resected specimen were also examined regarding TGF-beta1 expression.

RESULTS

In the resected carcinomas and adenomas, more frequent apoptosis and higher TGF-beta1 scores were observed in the Sulindac Group than in the Control Group. Overexpression of TGF-beta1 and apoptosis occurred in the same region in adenomas but not in carcinomas. A positive correlation between TGF-beta1 scores and apoptotic frequency was found in adenomas (P = 0.01, rho = 0.91) but not in carcinomas (P = 0.89, rho = 0.03).

CONCLUSION

We conclude that sulindac induces apoptosis in human colorectal carcinomas as well as in adenomas. Also, one of the antineoplastic effects of sulindac might be mediated by upregulating TGF-beta1 expression, particularly in colorectal adenomas.

Bowen's disease (squamous cell carcinoma in situ) in immunosuppressed patients treated with imiquimod 5% cream and a cox inhibitor, sulindac: potential applications for this combination of immunotherapy

BACKGROUND

Patients with chronic lymphocytic leukemia (CLL) often have a protracted course. However, all these patients are immunosuppressed and may have a high incidence of cutaneous malignancies.

OBJECTIVE

To determine if combination therapy using topical imiquimod cream 5% and the oral cyclooxygenase (COX) inhibitor are useful in the therapy of squamous cell carcinoma in situ (SCC in situ)/Bowen's disease in patients with long-standing CLL.

METHODS

Five CLL patients with head and neck cutaneous SCC in situ, which met criteria for Bowen's disease, were treated with topical 5% topical imiquimod cream and an oral COX inhibitor, sulindac 200 mg twice a day.

RESULTS

All patients showed clinical resolution and histologic clearing of the tumors after 16 weeks of therapy.

CONCLUSION

The local immune modulator, 5% imiquimod, in combination with a COX inhibitor, with its many potential antitumor effects may stimulate the innate and possibly the adaptive immune responses to clear these malignancies.

Phase I trial of exisulind (sulindac sulfone, FGN-1) as a chemopreventive agent in patients with familial adenomatous polyposis

Exisulind (sulindac sulfone; FGN-1), a metabolite of sulindac without known effects on prostaglandin synthesis, can promote apoptosis and inhibit tumorigenesis in preclinical systems. We performed a Phase I trial of this compound in patients with familial adenomatous polyposis (FAP) to examine the tolerability and safety of this drug in the cancer chemoprevention setting. Six patients each were treated with exisulind at doses of 200, 300, and 400 mg p.o. twice a day. Reversible hepatic dysfunction was noted in four of six patients treated at the 400-mg p.o., twice-a-day dose level, but in only one to two of six patients treated at each of the lower dose levels. The serum half-life of exisulind was 6-9 h; little drug accumulation was noted over time. A nonsignificant trend toward increased apoptosis in polyps was noted at the maximum tolerated dose, but no decrease in polyp numbers or significant effects on cellular proliferation was noted. After treatment, polyps tended to display a "halo" appearance grossly and mucinous differentiation histologically. The maximum safe dose of exisulind is 300 mg p.o. twice a day in patients with subtotal colectomies. Reversible hepatic dysfunction limits further dose escalation. A decrease in polyp numbers could not be demonstrated, but the trend toward increased apoptosis at the MTD and the observation of mucinous change histologically suggest that further investigation of drugs of this class might be warranted.

Drug-associated cholelithiasis: a case of sulindac stone formation and the incorporation of sulindac metabolites into the gallstones

A case of drug-associated cholelithiasis (sulindac chlecystohepatolithiasis) in a 63-yr-old woman is reported. The patient was admitted to our hospital to undergo treatment for rheumatoid arthritis of 20 yr duration. She was treated with nonsteroidal anti-inflammatory drugs (NSAID: sulindac). Two months later, she presented with right upper quadrant pain. Diagnostic studies including ultrasonography (US), computed tomography (CT) and endoscopic retrograde cholangiography (ERC), led to the diagnosis of cholecystohepatolithiasis. She underwent cholecystectomy and choledochotomy with an extraction of intrahepatic stones. The intrahepatic stones were light yellow in color with a claylike appearance. Unexpectedly, an infrared spectroscopic analysis of the stone showed it to consist of sulindac metabolites. In addition, the dilated segment of the intrahepatic bile duct naturally returned to its normal size after the discontinuation of the drug administration. This is the first reported case of sulindac stone formation in the bile duct. No similar problems with other NSAIDs have been reported previously.

Green tea and cancer chemoprevention

Worldwide interest in green tea as a cancer preventive agent for humans has increased, because it is non-toxic and it is effective in a wide range of organs. (-)-Epigallocatechin gallate (EGCG) is the main constituent of green tea; the others are (-)-epicatechin gallate, (-)-epigallocatechin and (-)-epicatechin (EC). This paper reports the results of our latest pharmacological and biochemical studies with 3H-EGCG, along with studies on human subjects. The study on bioavailability of 3H-EGCG in mice revealed the wide distribution of radioactivity in multiple organs. Specifically, radioactivity was found in all reported target organs of EGCG and green tea extract (digestive tract, liver, lung, pancreas, mammary gland and skin) as well as other organs (brain, kidney, uterus and ovary or testes) in mice. Recently, we demonstrated that EC enhanced incorporation of 3H-EGCG into human lung cancer cell line PC-9 cells. EC along with another cancer preventive agent sulindac also synergistically enhanced apoptosis in PC-9 cells induced by EGCG. Moreover, a case-control study on breast cancer patients revealed that high daily consumption of green tea was associated with a lower recurrence rate among Stages I and II patients. All the results suggest that consumption of green tea is a practical and effective cancer preventive both before cancer onset and after cancer treatment.

Chemopreventive efficacy of sulindac sulfone against colon cancer depends on time of administration during carcinogenic process

Epidemiological and model studies with laboratory animals have provided evidence that nonsteroidal anti-inflammatory drugs reduce the risk of colon cancer. Sulindac, a nonsteroidal anti-inflammatory drug, has been shown to inhibit azoxymethane (AOM)-induced colon carcinogenesis in rats when administered continuously before, during, and after carcinogen treatment (initiation and postinitiation periods) or when given continuously beginning 14 weeks after carcinogen administration (promotion/ progression stage). The present study was designed to investigate the chemopreventive efficacy of sulindac sulfone (exisulind), the sulfone metabolite of sulindac, when administered during the promotion/progression stage of colon carcinogenesis in comparison to the effect during the initiation and postinitiation periods. We have also studied the modulating effect of exisulind on colonic tumor apoptosis. At 5 weeks of age, groups of male F344 rats were fed diets containing 0%, 0.06%, and 0.12% exisulind. At 7 weeks of age, groups of animals were injected s.c. with AOM (15 mg/kg body weight, once weekly for 2 weeks). Animals intended for the promotion/progression study and receiving 0% exisulind were switched to an experimental diet containing 0.12% exisulind at 14 weeks after the second AOM treatment. All rats remained on their respective dietary regimens until the termination of the study, 50 weeks after the second AOM injection. Colon tumors were evaluated histopathologically for tumor type. Administration of 0.06% and 0.12% exisulind during the initiation and postinitiation periods significantly inhibited the incidence and multiplicity of invasive and/or noninvasive adenocarcinomas of the colon. The inhibition of colon tumorigenesis by exisulind was associated with a significant retardation of body weight gain shortly after sulfone administration and increased apoptosis in the colon tumors. In contrast, administration of the higher dose (0.12%) of exisulind during the promotion/progression stage had only minimal effects on colon tumorigenesis and apoptosis in the colon tumors, suggesting that early administration, but not late administration, may be required for chemopreventive efficacy of this drug.

Combination oral antiangiogenic therapy with thalidomide and sulindac inhibits tumour growth in rabbits

Neovascularization facilitates tumour growth and metastasis formation. In our laboratory, we attempt to identify clinically available oral efficacious drugs for antiangiogenic activity. Here, we report which non-steroidal anti-inflammatory drugs (NSAIDs) can inhibit corneal neovascularization, induced by basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF). This antiangiogenic activity may contribute to the known effects of NSAIDs on gastric ulcers, polyps and tumours. We found that sulindac was one of the most potent antiangiogenic NSAIDs, inhibiting bFGF-induced neovascularization by 50% and VEGF-induced neovascularization by 55%. Previously, we reported that thalidomide inhibited growth factor-induced corneal neovascularization. When we combined sulindac with thalidomide, we found a significantly increased inhibition of bFGF- or VEGF-induced corneal neovascularization (by 63% or 74% respectively) compared with either agent alone (P < 0.01). Because of this strong antiangiogenic effect, we tested the oral combination of thalidomide and sulindac for its ability to inhibit the growth of V2 carcinoma in rabbits. Oral treatment of thalidomide or sulindac alone inhibited tumour growth by 55% and 35% respectively. When given together, the growth of the V2 carcinoma was inhibited by 75%. Our results indicated that oral antiangiogenic combination therapy with thalidomide and sulindac may be a useful non-toxic treatment for cancer.

Decreased HER-2 tyrosine kinase expression in rectal mucosa of FAP patients following low-dose sulindac chemoprevention

As a part of the mechanisms of action in reversing FAP adenomas by the low-dose sulindac maintenance therapy (2 x 25 mg/patient per day), the extent of HER-2 proto-oncogene expression in the rectal mucosa seems to be of interest. Immunocytochemical analyses were performed in plasma and in rectal tissue of sulindac-treated FAP patients during an 18 months follow-up and compared with rectal tissue of patients with FAP, Crohn's disease, or rectal cancer or with healthy volunteers. HER-2 was significantly reduced and maintained in tissue under sulindac chemoprevention below base line levels of healthy individuals, but not in plasma. Therefore, a direct or indirect effect of sulindac as a tyrosine kinase inhibitor may be implicated. During NSAID treatment HER-2 protein expression as a prognostic tool seems to be of little clinical relevance.

Nonsteroidal anti-inflammatory drugs enhance glutathione S-transferase theta levels in rat colon

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been claimed to reduce cancer rates in oesophagus, stomach and colon of humans and laboratory animals. Recently we showed that dietary administration of NSAIDs enhanced glutathione S-transferase (GST) class alpha, mu and pi levels in the upper part of the rat gastrointestinal tract, with minor effects in the colon. Enhancement of GSTs, a family of detoxification enzymes consisting of class alpha, mu, pi and theta isoforms, might be one of the mechanisms leading to cancer prevention. The recently cloned GST class theta levels have not yet been studied in this respect. We now investigated whether the NSAIDs indomethacin, relafen, sulindac, ibuprofen, piroxicam, and acetyl salicylic acid (ASA), incorporated individually into the diet at 25, 200, 320, 400, 400 and 400 mg/kg, respectively, affect gastrointestinal GSTT1-1 and GSTT2-2 levels in male Wistar rats. GSTT1-1 and GSTT2-2 levels were determined in cytosolic fractions of oesophagus, gastric, small intestinal and colonic mucosa and liver by densitometrical analyses of Western blots after immunodetection with a monoclonal (GSTT1-1) or a polyclonal (GSTT2-2) antibody. Gastric GSTT2-2 levels were induced by ibuprofen (1.6x) and indomethacin (1.5x), and colonic levels were induced by ASA (1.7x). Colonic GSTT1-1 levels were elevated by all NSAIDs tested except for relafen (1.5-6.4x). In conclusion, enhancement of colonic GSTT1-1 levels seems to be a common working mechanism of NSAIDs. Enhanced enzyme activity, which may result from these higher GSTT1-1 levels, might lead to a more efficient detoxification of potential carcinogens and hence contribute to the prevention of colon carcinogenesis.

Solubilization and interaction of sulindac with polyvinylpyrrolidone K30 in the solid state and in aqueous solution

In this report the interactions of sulindac with polyvinylpyrrolidone K30 (PVP K30), both in the solid state and in aqueous solution, have been investigated. Solid dispersions of sulindac with PVP K30 were prepared by the solvent method in ethanol from various drug-to-polymer weight ratios. X-ray powder diffraction and differential scanning calorimetry have shown that PVP inhibits the crystallization of sulindac. The stabilization of the noncrystalline state of sulindac was shown by x-ray diffractometry after a 1-year storage. There was a considerable increase in the release rate of the drug when the polymer content was increased and the intrinsic dissolution rate values of these systems were calculated. From the UV spectra a bathochromic shift and a well-defined isosbestic point were observed at pH 2 and 6, which confirmed an interaction between the drug and the polymer in solution. Moreover, the apparent solubility of sulindac has been modified as a function of the polymer concentrations. The binding process between the drug and PVP was exothermic from the stability constant values at 25, 30, and 37 degrees C at pH 2.

Clinical and genomic influence of sulindac on rectal mucosa in familial adenomatous polyposis

PURPOSE

A study was performed to evaluate the antiproliferative effects of low doses of the nonsteroidal drug, sulindac, on adenomas and rectal mucosa in familial adenomatous polyposis and to analyze the influence on tumor-suppressor genes and on apoptosis.

METHODS

This was a prospective, controlled, nonrandomized Phase II dose-finding study for sulindac. The study group (n = 28) and control group (n = 10) underwent colectomy and ileorectal anastomoses, with repeated proctoscopy with endoluminal ultrasound and biopsies every three months. Dose-reduction of sulindac according to adenoma reversion was predetermined. Proliferation marker, Ki-67 (MIB1 and 5), on frozen or paraffin sections evaluated the antiproliferative effects; mutant p21ras, pantropic p53, mutant p53, and anti-bcl-2 were performed as enzyme-linked immunosorbent assay procedures and/or immunohistochemistry on paraffin sections.

RESULTS

All patients responded to sulindac after 24 weeks (at the latest). There was a significant reduction of adenomas and dose reduction to 67 mg/day after three years of therapy (Mann's test for trend, P < 0.001). Results consisted of 78 percent complete reversions, 22 percent partial reversions of adenomas at latest re-examination, and no influence on upper gastrointestinal tract adenomas. No influence was detected on repeated hemograms, liver, or renal function at high or low doses. There was a permanent antiproliferative effect (Ki-67) of low-dose sulindac, significant blocking of ras mutation activation, and a significant difference of untreated and treated mucosa in mutant p53 content (Wilcoxon's or Kruskal-Wallis each, P < 0.05). Reverse correlation of anti-bcl-2 and p53 immunostaining on mucosa sections was an indication of adenoma relapse.

CONCLUSIONS

Low-dose antiproliferative sulindac therapy is highly effective in adenoma reversion in familial adenomatous polyposis patients. Sulindac shows influence on tumor-suppressor genes and on apoptosis markers. An immunostaining correlation indicates adenoma relapse in flat microadenomas in advance of macroscopic appearance. Low-dose sulindac treatment may develop into an additive permnanent therapy for colectomized familial adenomatous polyposis patients.

Comparing sulindac with indomethacin for closure of ductus arteriosus in preterm infants

OBJECTIVES

A prospective study comparing the efficacy and side-effects of oral sulindac with intravenous indomethacin in clinically stable preterm infants (< 1750 g) requiring non-invasive closure of haemodynamically significant patent ductus arteriosus.

METHODOLOGY

As maturity and birthweight are the two major determinants of ductal closure, infants were matched as closely as possible for these parameters. An eligible patient was first assigned to the sulindac group and a subsequent patient with similar gestational age (+/-1 week) and birthweight (+/-100 g) to the previously recruited infant would automatically receive indomethacin. A total of eight infants were enrolled in each group.

RESULTS

The ductus arteriosus was successfully closed in all eight infants receiving indomethacin, and in seven of eight infants receiving sulindac. No significant differences were found with regards to the ductal size between the two groups at diagnosis or on each of the consecutive days of treatment (P > 0.25). More renal adverse effects were encountered in the indomethacin group. Significant differences in changes from baseline value for urine output, plasma sodium, urea and creatinine concentrations were noted at 24, 48 and 72 h after commencement of treatment between the two groups (P < 0.05). All the parameters returned to normal or pre-treatment levels 48 h after stopping therapy. Unexpectedly, severe gastrointestinal complications were encountered in the sulindac group.

CONCLUSIONS

Sulindac is capable of promoting ductal constriction in clinically stable preterm infants without compromising the renal function. The spectrum of gastrointestinal complications observed in sulindac treated infants were similar to those described for indomethacin. The use of sulindac for ductal closure in the preterm infant should remain experimental.

Effect of estrogen replacement therapy with or without concomitant nonsteroidal anti-inflammatory drugs on pulsatility and resistance index of uterine arteries in healthy postmenopausal women

OBJECTIVE

This study assesses the existence of a prostaglandin-mediated effect of estrogen on uterine arteries.

METHODS

The pulsatility index (PI) and the resistance index (RI) of 10 postmenopausal women aged 50 to 65 who had not been on estrogen replacement therapy (ERT) for the 6 weeks preceding the study were measured at baseline level (T1), after randomization for either placebo or nonsteroidal anti-inflammatory drug (NSAID) (600 mg of Sulindac for one day) (T2), after 1 week of washout and cross-over (T3). They were then supplemented with ERT (transdermal system 50 micrograms/d, twice a week, Systen) for a period of 3 months. PI and RI of uterine arteries were assessed again while using ERT (T4), after either placebo or NSAID for one day (T5) and after 1 week of placebo-NSAID cross-over (T6). Assays of total cholesterol as well as the HDL, HDL2, LDL, triglycerides, endothelin-1, lipoprotein (a), estradiol and FSH were also obtained at baseline before receiving ERT and after 3 months of ERT.

RESULTS

A small but significant increase of the PI was observed after NSAID intake as compared to the baseline measurement (P < .05), but no difference was observed for the RI. After estrogen treatment for 12 weeks, no difference was found between baseline measurements and the placebo intake or the NSAID intake.

CONCLUSION

These results do not confirm a modulation by prostaglandin of the estrogen cardioprotective effect, although it is possible that the study lacks power.

Effects of nonsteroidal anti-inflammatory drugs on glutathione S-transferases of the rat digestive tract

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been demonstrated to reduce cancer rates in oesophagus, stomach and colon of humans and animals. Earlier, we showed that high human gastrointestinal tissue levels of glutathione S-transferase (GST), a family of detoxification enzymes consisting of class alpha, mu, pi and theta isoforms, were inversely correlated with cancer risk. We investigated whether the NSAIDs indomethacin, ibuprofen, piroxicam, acetyl salicylic acid (ASA), and sulindac, supplemented in the diet for 2 weeks at 25, 400, 400, 400, and 320 ppm, respectively, influenced gastrointestinal GSTs in male Wistar rats. In cytosolic fractions of oesophagus, stomach, intestine and liver, GST activity towards 1-chloro-2,4-dinitrobenzene was measured, GST isozyme levels were determined by densitometrical analysis of Western blots after immunodetection with monoclonal antibodies, and glutathione levels were determined by HPLC. GST activity and GST mu levels were increased (1.2-1.8 x) in oesophagus and small intestine by indomethacin, ibuprofen, piroxicam and sulindac. GST alpha levels were induced (1.2-2.8 x) in stomach by piroxicam, in small intestine by indomethacin, ibuprofen, piroxicam and sulindac, and in liver by piroxicam. GST pi levels were raised (1.9-3.6 x) in stomach by ibuprofen, ASA, and sulindac, and in small intestine by indomethacin, piroxicam, ASA, and sulindac. Glutathione levels were raised (1.2-2.3 x) by indomethacin and ASA in small intestine and by piroxicam in oesophagus. Enhancement of GSTs in the upper part of the digestive tract, resulting in a more efficient detoxification, may explain in part the anticarcinogenic properties of NSAIDs.

Inhibition of lung tumourigenesis by sulindac: comparison of two experimental protocols

The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent lung carcinogen in mice and is most likely involved in the aetiology of tobacco-induced lung cancer. Two protocols using NNK and A/J mice have been developed. In the single-dose protocol, each mouse was injected once with 2 mg of NNK. In the 7-week protocol, each mouse received 9.1 mg of NNK in drinking water during 7 weeks. Mice were killed 16 weeks after NNK treatment. We observed a near-Gaussian distribution in the number of tumours per mouse in the single protocol, but not in the 7-week protocol. In the 7-week protocol, a significant number (8.6%) of mice had more than 20 tumours/mouse. In the single-dose protocol, no mouse had more than 20 tumours. Sulindac at a dose of 123 mg/kg of diet inhibits lung tumourigenesis in the 7-week protocol, but not in the single-dose protocol. We observed that the inhibition of tumourigenesis in the 7-week protocol was proportional to the logarithm of the dose of sulindac between 15 and 123 mg/kg of diet. Treatment of mice for 7 weeks inhibits the primary humoral response to sheep red blood cells by 70%. This observation is particularly significant considering that NNK is present in tobacco smoke and that tobacco smoking suppresses both the specific and non-specific humoral and cellular immunity. Single injections of 2.0, 3.5 or 5.0 mg of NNK had no effect on this response. Our results suggest that the immunosuppressive effects of NNK contribute to its high carcinogenic potency particularly in sustained or life-time exposure models. We hypothesize that sulindac promotes the recovery of immune system from the NNK-mediated suppression observed in the 7-week protocol. This study illustrates the importance of selecting the most appropriate protocol of carcinogen treatment in investigating the efficacies of cancer chemopreventive agents.

Sulindac for periampullary polyps in FAP patients

BACKGROUND

Gastro-duodenal polyps develop in up to 90% of familial adenomatous polyposis (FAP) patients and periampullary carcinoma is one of the most common extra-colonic malignancies in this syndrome. Periampullary adenomas have been shown to be precursor lesions to periampullary carcinoma. Sulindac, a non-steroidal anti-inflammatory drug, has been reported to cause regression of rectal polyps in FAP patients, however its role in periampullary polyp regression is unclear.

METHODS

In May 1993, a prospective study was begun to evaluate the role of sulindac in prevention of polyp recurrence after resection of large (> 1 cm) duodenal polyps in FAP patients. Eight patients, mean age 50 years (range 35 to 65), with documented large periampullary polyps were placed on sulindac 150 mg twice daily. Prior to enrollment, all patients had their large polyps removed from the periampullary region by interventional endoscopy or by surgery. All patients had multiple small residual duodenal polyps. Follow-up was performed by one experienced endoscopist with a side-viewing video endoscope. Endoscopy was performed 6 monthly. Median follow-up time was 17.5 months (range 10 to 24 months).

RESULTS

In 3 patients, sulindac was discontinued due to side effects: abdominal cramps (n = 2) and upper G-I bleeding (n = 1). None of the patients had regression of small periampullary polyps. In addition, one patient developed an invasive periampullary carcinoma while on sulindac and 3 patients developed large recurrent periampullary polyps requiring further treatment.

SUMMARY

In our experience, sulindac is of no significant benefit for the control of periampullary polyps in FAP. Effective medical treatment of these polyps is still lacking.

Differential activity of aspirin, ketoprofen and sulindac as cancer chemopreventive agents in the mouse urinary bladder

In vivo studies were conducted to compare the activity of three non-steroidal anti-inflammatory drugs as inhibitors of urinary bladder carcinogenesis induced in B6D2F1 (BDF) mice by N-butyl-N-(4-hydroxybutyl)nitrosamine (OH-BBN). Mice received continuous dietary exposure to non-toxic doses of aspirin, sulindac or ketoprofen beginning 1 week prior to the first of eight weekly doses of 7.5 mg OH-BBN; studies were terminated at 24 weeks after the first carcinogen dose. Both dose levels of sulindac (200 and 400 mg/kg diet) and both dose levels of ketoprofen (40 and 80 mg/kg diet) reduced the incidence of transitional cell carcinoma of the urinary bladder by >70% from that seen in dietary controls. The high dose of sulindac conferred the greatest protection against bladder cancer induction. In contrast, when administered at 400 and 800 mg/kg diet aspirin was inactive as a chemopreventive agent in the OH-BBN/BDF bladder cancer model. The significant potency of sulindac and ketoprofen as inhibitors of urinary bladder carcinogenesis, when considered with their history of safe human use, suggests that these agents merit further study as drugs for cancer chemoprevention in this target tissue.

Absorption of sulindac from a novel (Pro-SorbTM) liquid formulation

The absorption of sulindac from two different 200 mg oral dosage forms, Pro-SorbTM liquid and Clinoril tablets, was compared following administration to eight healthy human volunteers. Subjects received both formulations according to a randomized crossover design and blood samples were collected at selected times during 24 h. Concentrations of both sulindac and its active sulphide metabolite were determined by HPLC and individual serum concentration versus time profiles were constructed. Maximal serum concentrations (Cmax) and area under the curve values (AUClast and AUC0-infinity) were compared for both sulindac and sulindac sulphide. The results indicate that the rate and extent of absorption of sulindac from Pro-SorbTM liquid are significantly greater than those from Clinoril tablets, a finding consistent with the observation that the liquid form produces less gastric irritation following oral administration.

Phase I trial of sulindac plus 5-fluorouracil and levamisole: potential adjuvant therapy for colon carcinoma

Epidemiological studies indicate that nonsteroidal anti-inflammatory agents may reduce colorectal cancer incidence and mortality. Moreover, sulindac has been shown to attenuate the growth and progression of colonic neoplasms in an experimental model of colon carcinoma and in patients with familial adenomatous polyposis. To determine whether sulindac (300 mg/day) would increase toxicity associated with 5-fluorouracil (5-FU) and levamisole, 15 patients with advanced colorectal cancer were treated. Median treatment duration was 3 (range, 0.6-6.0) months, and median age was 56 years (33% >/= 60 years). All patients had failed prior 5-FU-based therapy, had measurable disease, and were evaluable for toxicity. Grade III/IV granulocytopenia occurred in four patients; three patients had received prior pelvic irradiation resulting in a predisposition to myelosuppression. Two patients developed grade III anemia, and occult gastrointestinal bleeding was suspected in one. No other grade II or greater gastrointestinal or other nonhematological toxicity occurred. One patient had a partial response, 3 patients had disease stabilization, and 10 patients progressed on study. Our results indicate that sulindac does not significantly increase short-term toxicity associated with 5-FU and levamisole. To determine whether sulindac increases the efficacy of adjuvant chemotherapy, we propose a phase III randomized trial in patients with lymph node-positive colon cancer.