A phase II study of CPT-11, a new derivative of camptothecin, for previously untreated non-small-cell lung cancer

Antitumoral effect of irinotecan (CPT-11) on an experimental model of malignant neuroectodermal tumor

Irinotecan (CPT-11) is a topoisomerase I inhibitor with antitumor activity on a wide variety of neoplasms in several preclinical studies, but it showed poor efficacy in patients with nervous system tumors. We have carried out an experimental study in order to evaluate the effect of CPT-11 on the growth of a subcutaneously implanted malignant neuroectodermal tumor, after administration by different routes. The results showed that CPT-11 administration by intraperitoneal injections (at dose 10 mg/kg, 5 days per week, for 2 weeks, followed by 7-days rest period--one course--to a total of two courses) had no significant antitumor effect. Nevertheless, continuous infusion by intraperitoneal osmotic minipump over 28 days (at an infusion rate of 4.4 microg/h) showed a significant delay in tumor growth in 4 weeks of the implantation. The best antitumor effects were observed after CPT-11 intratumoral administration (at dose of 5 mg/kg, 5 days per week, for 2 weeks, followed by 7-days rest period, to a total of three courses) reaching tumor regression in the treated animals. These results suggest the utility of CPT-11, by means of intralesional administration, on malignant tumors of the nervous system.

Phase I study of irinotecan in pediatric patients with malignant solid tumors

PURPOSE

To determine the dose-limiting toxicity, maximum tolerated dose, and potential efficacy of irinotecan in children with refractory malignant solid tumors.

PATIENTS AND METHODS

In the present phase I clinical trial, 28 patients received irinotecan 50 to 200 mg/m2 per day by intravenous 2-hour infusion over the course of 3 days, repeated once after an interval of 25 days. Fifty-one treatment courses were administered to these patients.

RESULTS

Dose-limiting toxicities were observed at the dose of 200 mg/m2 per day for 3 days. Diarrhea and hematopoietic toxicities were the dose-limiting factors, and the former required support with intravenous fluid administration. The occurrence of vomiting was variable. Decreases in clinical tumor marker levels were observed in the majority of patients who received two cycles of irinotecan 80 mg/m2 per day to 200 mg/m2 per day over the course of 3 days, and partial response was attained in four patients who received irinotecan in two cycles of 140 mg/m2 per day to 200 mg/m2 per day over the course of 3 days. Pharmacokinetic studies showed that the plasma concentration of irinotecan and its active metabolite SN-38 ranged from 93 to 2,820 ng/mL and 5.2 to 34.8 ng/mL, respectively, during 3-day infusions of irinotecan 200 mg/m2 per day. The mean clearance of irinotecan was 14.54 L/h per m2 (range 8.45-20.83 L/h per m2).

CONCLUSION

The maximum tolerated dose was determined to be a dose of irinotecan between 160 mg/m2 per day and 180 mg/m2 per day administered over the course of 3 consecutive days on an inpatient basis, repeated once after 25 days off, and our results indicate that irinotecan is a promising anticancer agent that is worthy of phase II trials in pediatric solid tumors.

Topoisomerase I inhibitors combination chemotherapy in non-small cell lung cancer

In the last years, the main topoisomerase I inhibitors (TP1-I) (i.e. topotecan and irinotecan) have been used in combination chemotherapy in non-small cell lung cancer. Several drugs (also alternative to cisplatin) have been used in combination with TP1-I, but to date the higher remission rate obtained with combinations is not translated into a more prolonged survival in comparison with TP1-I given alone. On the other hand, the toxicity of TP1-I combinations is greater than those of TP1-I used alone. The superior efficacy of combinations versus TP1-I used alone remains an open question. Furthermore, the best schedule for TP1-I has not been completely elucidated. Randomised studies are few (only two phase III trials) and only controlled studies will be able to clarify the best TP1-I combination regimen.

Cisplatin and irinotecan (CPT-11) as second-line treatment in patients with advanced non-small cell lung cancer

Irinotecan (CPT-11) and cisplatin (P) are both active agents against non-small cell lung cancer (NSCLC), and their combination has shown in vitro an additive or synergistic effect. We conducted a phase II study to determine the toxicity and efficacy of their combination as salvage treatment in patients with advanced NSCLC progressing after a docetaxel-based front line regimen. Forty-four patients with histologically confirmed NSCLC were enrolled. The patients' median age was 60.5 years; 39 patients (87%) were male; 38 (86%) had stage IV disease; and 32 (73%) had a performance status (WHO) 0-1. CPT-11 was administered as a 60 min i.v. infusion at a dose of 100 mg/m(2) on day 1 and 110 mg/m(2) on day 8; P was administered at a dose of 80 mg/m(2) on day 8 after CPT-11 administration. Treatment was repeated every 3 weeks. A total of 159 chemotherapy cycles was administered. In an intention-to-treat analysis, nine patients (22; 95% CI: 9.28-34.62%) achieved a partial response (PR), 8 (20%) had stable disease (SD), and 24 (58%) progressive disease (PD). The median duration of response was 4 months, the median time-to-progression (TTP) 8 months, and the median survival for the entire group 8 months. Grade 3-4 neutropenia was observed in 20 (46%) patients and in four cases this was febrile, requiring patient's hospitalisation. Grade 3-4 thrombocytopenia occurred in four (9%) patients. Grade 3-4 diarrhoea was seen in 12 (27%) patients and three of them required hospitalisation. Grade 2-3 neurotoxicity was observed in two (4%) patients and grade 2-3 fatigue in 14 (32%). Other toxicity was mild and no treatment-related death was reported. The combination of CPT-11 and P is a safe, well-tolerated, and active regimen for the treatment of patients with advanced NSCLC previously treated with a docetaxel-based front-line regimen.

DNA topoisomerases as targets for anticancer drugs

DNA topoisomerases are essential enzymes that regulate the conformational changes in DNA topology by catalysing the concerted breakage and rejoining of DNA strands during normal cellular growth. Over the past few years there has been considerable pharmacological interest in these enzymes because inhibitors of DNA topoisomerases represent a major class of anticancer drugs. This review highlights topoisomerase-targeting drugs that have shown promising anticancer activities. The mechanisms by which those drugs interfere with the catalytic cycles of type I and type II DNA topoisomerases and the factors involved in the development of resistance to these drugs are discussed.

Phase I clinical and pharmacogenetic trial of irinotecan and raltitrexed administered every 21 days to patients with cancer

PURPOSE

Irinotecan and raltitrexed display schedule-dependent synergy in vitro, which supports the clinical investigation of the combination. Functional polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene result in intracellular redistribution of folate derivatives, which may affect raltitrexed-associated cytotoxicity.

PATIENTS AND METHODS

Patients with a range of solid cancers and good performance status received irinotecan as a 90-minute infusion on day 1 and raltitrexed as a 15-minute infusion on day 2, repeated every 21 days. Samples were collected for MTHFR C677T genotyping and fasting plasma homocysteine during the first cycle.

RESULTS

Thirty-nine assessable patients received 127 cycles of therapy. Irinotecan doses ranged from 100 to 350 mg/m(2), and raltitrexed, 1.0 to 4.0 mg/m(2). Raltitrexed doses of more than 3.0 mg/m(2) were not tolerated and were associated with dose-limiting asthenia, diarrhea, and AST/ALT elevation. Irinotecan/raltitrexed doses of 350/3.0 mg/m(2) were well-tolerated; principal toxicities included neutropenia, diarrhea, and fatigue. Two partial responses were observed in patients with pretreated gastroesophageal cancers. Homozygotes with the MTHFR 677 TT polymorphism incurred significantly less raltitrexed-associated toxicity than those with either wild-type or heterozygous genotypes (P = .05). No significant differences were noted in plasma homocysteine values between the genotypic subtypes, and plasma homocysteine levels did not predict the risk of toxicity.

CONCLUSION

Irinotecan and raltitrexed doses of 350 and 3.0 mg/m(2) are recommended for further study on a day 1, 2 schedule every 21 days. Efficacy results suggest that trials in upper and lower gastrointestinal malignancies are warranted. MTHFR C677T genotypes may be predictive of clinical raltitrexed toxicity.

Toxicity of irinotecan (CPT-11) and hepato-renal dysfunction

Various clinical and laboratory parameters have been investigated for their ability to predict toxicity arising from the use of the anticancer drug, irinotecan (CPT-11). In particular, patients deficient in the conjugation of SN-38, a metabolite of CPT-11, are known to be at greater risk. We describe one case of a patient with metastatic colorectal cancer treated with a single dose of CPT-11 at 125 mg/m(2). Although this patient lacked any known predictive factors for toxicity, he experienced severe side-effects several days later. We hypothesized that the toxicity in this patient was due to compromised SN-38 conjugation. Plasma samples were analyzed by reversed-phase high-performance liquid chromatography assay for CPT-11 and its metabolites at 96, 144, 168, 192 and 288 h post-administration. We observed that the concentrations of both the parent drug and its metabolites were markedly raised (11- to 60-fold expected). Additionally the estimated terminal half-lives were 1.5-7 times those expected (29.5, 101, 39.6 and 41.8 h for CPT-11, APC, SN-38G and SN-38, respectively). We conclude that the toxicity in this patient was not caused by deficient SN-38 conjugation, but by decreased drug excretion through both hepatic and renal routes.

Fractionated administration of irinotecan and cisplatin for treatment of non-small-cell lung cancer: a phase II study of Okayama Lung Cancer Study Group

A phase II study of fractionated administration of irinotecan (CPT-11) and cisplatin (CDDP) in patients with non-small-cell lung cancer (NSCLC) was conducted. Between January 1996 and January 1998, 44 previously untreated patients with stage IIIB or IV NSCLC were enrolled. CDDP at a dose of 60 mg x m(-2) was given first and followed by CPT-11 at a dose of 50 mg x m(-2). Both drugs were given by 1-hour infusion on days 1 and 8, and repeated every 4 weeks up to 4 cycles. 42 patients were evaluated for response and 44 for survival and toxicity. 20 patients (48%: 95% confidence interval 32-63%) achieved an objective response. The median duration of responses was 8 months, and the median survival time and the 1-year survival rate were 12.5 months and 56.8%, respectively. Major toxicities were neutropenia and diarrhoea. Grade 3 or 4 neutropenia occurred in 70.5% of the patients and one patient died of sepsis. Grade 3 or 4 diarrhoea was experienced in 25.0%, but manageable by conventional therapy. In conclusion, fractionated administration of CPT-11 and CDDP was highly effective for advanced NSCLC with manageable toxicities.

Chemotherapy-induced pulmonary toxicity in lung cancer management

Chemotherapy is the cornerstone of therapy in many stages of lung cancer. Many diagnostic options have to be taken into account when a patient suffering from lung cancer presents with nonspecific, respiratory, clinical manifestations. A multidisciplinary diagnostic approach is then warranted. The top priority is to rule out those life-threatening causes, such as lung infection, that could be properly treated if a right diagnosis is early. To reach a definite diagnosis frequently requires that one or more diagnostic, pneumologic techniques are performed. Regarding to drug-induced pulmonary disease, prevention is mandatory. In this review we have tried to highlight the risk and characteristics of cytostatic-induced pulmonary toxicity caused by those agents that have been commonly employed to treat lung cancer for the last decades. When treating lung cancer patients, a high clinical suspicion of chemotherapy-induced lung toxicity should be kept in mind since an early withdrawal of the offending drug is the most efficacious therapy.

Docetaxel in combination with gemcitabine plus rhG-CSF support as second-line treatment in non-small cell lung cancer. A multicenter phase II study

BACKGROUND

Docetaxel in combination with gemcitabine is an active front-line chemotherapy regimen against non-small cell lung cancer (NSCLC) with acceptable toxicity. A multicenter phase II study was conducted in order to determine the toxicity and efficacy of this combination, as salvage treatment in patients progressing after a cisplatin-based front line regimens.

PATIENTS AND METHODS

Thirty-two patients with histologically confirmed, bidimensionally measurable NSCLC, who failed prior cisplatin-based chemotherapy were enrolled. The patients' median age was 62.5 years, 29 (91%) were male, 23 (72%) had disease stage IV, and 22 (69%) had a performance status (WHO) 0-1. Gemcitabine (900 mg/m(2)) was administered on days 1 and 8 and docetaxel (100 mg/m(2)) on day 8, after appropriate premedication. rhG-CSF (150 microg/m(2)) was given prophylactically from day 9 to 15. Treatment was repeated on an outpatient basis every three weeks.

RESULTS

A total of 127 chemotherapy cycles were administered. In an intention-to-treat analysis five patients (15.6%; 95% CI: 3.04-28.21%) achieved a partial response, 11 (34.4%) stable disease, and 16 (50%) progressive disease. The median duration of response was 9 months, the median TTP 7 months, and the overall median survival 6.5 months; the overall 1-year survival probability was 27.6%. Grade 3/4 neutropenia was observed in five (15.6%) patients and in two of them associated with fever. Grade 3 anemia and thrombocytopenia occurred in three (9%) and two (6.5%) patients, respectively. Non-hematologic toxicity was very mild with only one episode of grade 4 diarrhea and mucositis, respectively; two (6%) patients complained for grade 3 asthenia.

CONCLUSION

The combination of gemcitabine and docetaxel with prophylactic use of rhG-CSF is a safe and well-tolerated regimen for the treatment of patients with advanced NSCLC, who failed front-line treatment with cisplatin-based regimens.

Irinotecan (CPT-11) in Triplet Combinations in Patients with Advanced Non–Small-Cell Lung Cancer: A Review and Report of a Phase I/II Trial

The objectives of this phase I/II trial were to determine the maximum tolerated dose, toxicities, and the dose suitable for phase II/III trials of irinotecan (CPT-11) combined with paclitaxel and carboplatin in patients with advanced non small-cell lung cancer (NSCLC). Seventy-three patients with stage IIIB/IV NSCLC were enrolled in this multicenter, phase I/II study. The initial regimen was paclitaxel 225 mg/m2 over 3 hours, followed by carboplatin at an area under the curve (AUC) of 6 over 30 minutes on day 1 and CPT-11 starting at 40 mg/m2 over 90 minutes on days 1 and 8, every 3 weeks. Dose-limiting toxicity occurred in three of the original seven patients. The regimen was amended with doses reduced to paclitaxel 175 mg/m2 over 3 hours, carboplatin AUC = 5, and CPT-11 at 40 mg/m2, all on day 1 every 3 weeks. Dose escalation of CPT-11 proceeded to 80 mg/m2 and 125 mg/m2 before dose-limiting toxicities were experienced. Subsequent patients received an intermediate CPT-11 dose of 100 mg/m2. Doses suitable for phase II study were determined to be paclitaxel 175 mg/m2 over 3 hours, carboplatin AUC = 5, and CPT-11 100 mg/m2. The pri-mary first-cycle dose-limiting toxicities were neutropenia and diarrhea. The most common grade 3/4 toxicity observed during all cycles was neutropenia. On the phase I portion of the study, objective tumor response was observed in 39% (12 of 31, 95% confidence interval: 22%-58%). The median time to tumor progression was 6.8 months, median survival was 11.0 months, and 1-year survival probability was 0.46. These data were confirmed in the phase II portion with a 30% objective response rate, median time to progression of 5.6 months, median survival of 12.5 months, and a 1-year survival probability of 0.50. In conclusion, CPT-11 100 mg/m2, paclitaxel 175 mg/m2, and carboplatin AUC = 5 given every 3 weeks can be safely administered in patients with advanced NSCLC. Neutropenia and diarrhea are the dose-limiting toxicities. The combination shows appreciable activity, and survival data are favorable, warranting further study of this regimen. A review of other irinotecan-containing triplet combinations is presented.

Irinotecan and Platinums in the Treatment of Non–Small-Cell Lung Cancer

Lung cancer is the leading cause of cancer death in the United States and in the world. In the United States, lung cancer ranks first in cancer deaths for both men and women. The 5-year survival rate is only 15%, but this has improved considerably from the 5% rate in the early 1960s. For many years, the standard therapy for patients with advanced, stage IIIB and IV non small-cell lung cancer (NSCLC) was best supportive care, which consisted of palliative radiotherapy, pain management, and other symptom management. The median survival for these patients was only 4 months, and more than 85% died in the first year after diagnosis. Cisplatin was the first drug that was shown to prolong the survival of patients with advanced lung cancer. Meta-analyses of randomized trials showed that cisplatin reduced the hazard rate of death by 26%, increased median survival from 4 to 6 months, and increased 1-year survival from 15% to 25%. Cisplatin-based therapy also relieved symptoms in the majority of patients and improved the quality of life as assessed by patients themselves. Still, further advances are desperately needed, as three fourths of the cisplatin-treated patients die within a year of diagnosis. Topoisomerase I inhibitors are a new class of chemotherapeutic agents introduced into lung cancer therapy during the 1990s. Irinotecan (CPT-11) was shown to be active in patients with both small-cell and non small-cell lung cancers. The activity of irinotecan in advanced NSCLC made it logical to combine irinotecan with the two platinums, cisplatin and carboplatin. The combination of irinotecan with cisplatin produced response rates of about 40% in phase II trials conducted in previously un-treated patients with advanced NSCLC. The median survival in these studies ranged from 6-8 months, and the 1-year survival rates ranged from 40%-60%. Because carboplatin is more convenient and better tolerated than cisplatin, a number of more recent phase II trials have evaluated the combination of irinotecan and carboplatin in patients with advanced NSCLC. These trials produced results similar to those achieved with irinotecan/cisplatin and with other two-drug combinations such as paclitaxel/carboplatin and gemcitabine/ cisplatin. The excellent activity of the two-drug combination or irinotecan and a platinum led to trials of three-drug combinations, such as irinotecan/carboplatin/paclitaxel. Preliminary results from these studies showed excellent survival, although the toxicity required some dosage reductions. Randomized trials will be necessary to determine whether such three-drug combinations will be preferred over standard two-drug combinations.

Prevention of irinotecan (CPT-11)-induced diarrhea by oral alkalization combined with control of defecation in cancer patients

It has been reported that 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothecin (CPT-11) and its active metabolite, 7-ethyl-10-hydroxy-camptothecin (SN-38), have absorption characteristics of weakly basic drugs, suggesting that alkalization of the intestinal lumen might reduce reabsorption and its attendant side effects. Furthermore, stasis of stools containing these compounds is thought to induce damage to the intestinal mucosa. The prevention of CPT-11-induced side effects by oral alkalization (OA) combined with control of defecation (CD) was estimated in a case-control study of lung cancer patients. Coinciding with day 1 of CPT-11 infusion and for 4 days thereafter, OA and CD were practiced utilizing orally administered sodium bicarbonate, magnesium oxide, basic water and ursodeoxycholic acid. OA involved the daily use of all four therapeutics, and CD required doses of up to 4.0 g/day of magnesium oxide and 2 L/day of excess basic water. From three ongoing prospective phase I/II studies, we selected 37 consecutive patients who were treated with CPT-11 in combination with cisplatin in the presence of OA and CD (group B). Thirty-two control subjects who were matched to the background characteristics of the case patients were treated with the same regimen in the absence of OA and CD (group A). Toxicities induced by the CPT-11/cisplatin combination were evaluated and analyzed in group A and group B in a case-control format. The use of OA and CD resulted in significantly higher stool pH (p < 0.0001), while reducing the incidence of delayed diarrhea (> or = grade 2: group A 32.3% versus group B 9.4%; p = 0.005), nausea (p = 0.0001), vomiting (p = 0.001) and myelotoxicity, especially granulocytopenia (p = 0.03) and lymphocytopenia (p = 0.034). In addition, dose intensification was well tolerated in patients receiving OA and CD, allowing dose escalation from 35.6 +/- 6.0 to 39.9 +/- 5.6 mg/m(2)/week (p < 0.001). Tumor response rates for non-small cell lung cancer were 59.3% (16/27 patients) in group B compared with 38.5% (10/26 patients) in group A. Multivariate analysis revealed that the risk of CPT-11-induced delayed diarrhea greater than grade 2 was associated with OA and CD (odds ratio for delayed diarrhea, 0.14 with use of OA and CD; 95% confidence interval, 0.05 to 0.4; p = 0.0002) and age (odds ratio, 1.08 per increase in age; 95% confidence interval, 1.02 to 1.15; p = 0.009). OA and CD appear to be useful in preventing the dose-limiting side effects of CPT-11 noted in clinical practice, mainly nausea, vomiting, granulocytopenia and especially delayed diarrhea. Risk factors statistically associated with delayed diarrhea include advanced age and the use of CPT-11 without OA and CD.

Prevention of irinotecan (CPT-11)-induced diarrhea by oral alkalization combined with control of defecation in cancer patients

It has been reported that 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothecin (CPT-11) and its active metabolite, 7-ethyl-10-hydroxy-camptothecin (SN-38), have absorption characteristics of weakly basic drugs, suggesting that alkalization of the intestinal lumen might reduce reabsorption and its attendant side effects. Furthermore, stasis of stools containing these compounds is thought to induce damage to the intestinal mucosa. The prevention of CPT-11-induced side effects by oral alkalization (OA) combined with control of defecation (CD) was estimated in a case-control study of lung cancer patients. Coinciding with day 1 of CPT-11 infusion and for 4 days thereafter, OA and CD were practiced utilizing orally administered sodium bicarbonate, magnesium oxide, basic water and ursodeoxycholic acid. OA involved the daily use of all four therapeutics, and CD required doses of up to 4.0 g/day of magnesium oxide and 2 L/day of excess basic water. From three ongoing prospective phase I/II studies, we selected 37 consecutive patients who were treated with CPT-11 in combination with cisplatin in the presence of OA and CD (group B). Thirty-two control subjects who were matched to the background characteristics of the case patients were treated with the same regimen in the absence of OA and CD (group A). Toxicities induced by the CPT-11/cisplatin combination were evaluated and analyzed in group A and group B in a case-control format. The use of OA and CD resulted in significantly higher stool pH (p < 0.0001), while reducing the incidence of delayed diarrhea (> or = grade 2: group A 32.3% versus group B 9.4%; p = 0.005), nausea (p = 0.0001), vomiting (p = 0.001) and myelotoxicity, especially granulocytopenia (p = 0.03) and lymphocytopenia (p = 0.034). In addition, dose intensification was well tolerated in patients receiving OA and CD, allowing dose escalation from 35.6 +/- 6.0 to 39.9 +/- 5.6 mg/m(2)/week (p < 0.001). Tumor response rates for non-small cell lung cancer were 59.3% (16/27 patients) in group B compared with 38.5% (10/26 patients) in group A. Multivariate analysis revealed that the risk of CPT-11-induced delayed diarrhea greater than grade 2 was associated with OA and CD (odds ratio for delayed diarrhea, 0.14 with use of OA and CD; 95% confidence interval, 0.05 to 0.4; p = 0.0002) and age (odds ratio, 1.08 per increase in age; 95% confidence interval, 1.02 to 1.15; p = 0.009). OA and CD appear to be useful in preventing the dose-limiting side effects of CPT-11 noted in clinical practice, mainly nausea, vomiting, granulocytopenia and especially delayed diarrhea. Risk factors statistically associated with delayed diarrhea include advanced age and the use of CPT-11 without OA and CD.

Effect of bile acids on the uptake of irinotecan and its active metabolite, SN-38, by intestinal cells

The intestinal transport of irinotecan (CPT-11) and its active metabolite, SN-38, has been previously reported (K. Kobayashi et al., Int. J. Cancer, 83 (1999) 491-496). In the present study, the effect of the two major primary bile acids, cholic acid (CA) and taurocholic acid (TCA), on the uptake of CPT-11 and SN-38 by hamster intestinal epithelial cells was investigated. These two bile acids at concentrations up to 200 microM did not directly alter the cellular uptake of CPT-11 and SN-38. However, under physiologically acidic intestinal pH conditions, micelle formation induced by 20 mM TCA significantly reduced the cellular uptake of CPT-11 and SN-38 by 60% and 80%, respectively.

Combination of paclitaxel and etoposide in the treatment of advanced non-small cell lung cancer: a phase I-II study

Thirty-six patients (pts) with unpretreated advanced non-small cell lung cancer (NSCLC) stages IIIB and IV were enrolled in this two-stage phase I-II study aimed to establish the maximum tolerated dose (MTD) of paclitaxel and to evaluate the efficacy and safety of paclitaxel combined with etoposide every 3 weeks for a maximum of 6 courses, increasing the dose of paclitaxel according to a modified Fibonacci scheme. Nineteen pts were enrolled in the first stage and 17 pts in the second stage. The characteristics of the pts were as follows: median age 56 years (40-70), median Karnofsky's Performance Status 80% (70-80), 11 pts were stage IIIB and 25 pts stage IV. The doses of etoposide administered were 50 mg/m2 for 15 pts and 100 mg/m2 for 21 pts. MTD has not been reached and the study proceeded with the dose of paclitaxel 250 mg/m2. We obtained 9 (25%) partial remissions (PR) and 11 (31%) stable disease (SD) in 33 objectively evaluable pts. Median time to progression (TTP) was 4 months (0.3-21), median survival was 9.3 months (0.3-27). The main toxicity was neutropenia and neurotoxicity, while the gastrointestinal toxicity was mild. Two pts deceased after the first course. The causes of death were necrotizing enteritis in the first pt and congestive heart failure in the second pt. A total of 156 courses were administered at 7 dose levels, with a median of 4 courses per patient (1-6). The results seem to support the use of this combination in advanced non-small cell lung cancer.

Phase I study of carboplatin, docetaxel and irinotecan with recombinant human granulocyte colony stimulating factor support in patients with advanced non-small cell lung cancer

A phase I study was conducted in patients with stage IIIB or IV non-small cell lung cancer to determine the maximum tolerated dose (MTD) of irinotecan combined with a fixed schedule of docetaxel and carboplatin with recombinant human granulocyte colony stimulating factor (rhG-CSF) (nartograstim) support. Docetaxel was given at 60 mg/m2 on day 1 with carboplatin. The dose of carboplatin was calculated using the Calvert formula to achieve an estimated AUC of 5.0 mg/ml x min. Irinotecan was administered at a starting dose of 40 mg/m2 on day 1 and increased in increments of 10 mg/m2. rhG-CSF was given at 1 microg/kg on days 5-15. Cycles were repeated every 3 weeks. Between February 1998 and March 1999, 22 patients were enrolled in this phase I study. Five patients were chemotherapy naive. The MTD of irinotecan was 60 mg/m2. Diarrhea was considered to be the dose-limiting toxicity. The irinotecan dose intensity of 16.7 mg/m2/week was low compared with other irinotecan-containing regimens. The overall response rate was 38.1% and median survival was 278 days. Irinotecan 50 mg/m2 in combination with 60 mg/m2 docetaxel and carboplatin on day 1 with rhG-CSF support is recommended for phase II study. The response rate and survival data in this phase I study are encouraging.

Irinotecan-associated pulmonary toxicity

We present the circumstances surrounding a 57-year-old Caucasian man with advanced colorectal cancer who developed relapsing interstitial lung disease following a single exposure to irinotecan (CPT-11). Progressive pulmonary insufficiency and death were reported in the initial Japanese studies, despite institution of empiric steroid therapy for a syndrome similar to that which our patient experienced. As a result, patients with compromised pulmonary function were generally excluded from US clinical trials. Notwithstanding this, cough and dyspnea were reported in approximately 20% of patients in the US studies. As the clinical indications for the use of this agent expand, we describe irinotecan-associated interstitial pneumonitis as a serious potential adverse effect. Patients with pre-existing pulmonary disease may be at higher risk for this complication and clinicians should be alert to this possibility.

Clinical use of topoisomerase I inhibitors in anticancer treatment

The camptothecin analogs topotecan and irinotecan have shown to be among the most effective anticancer agents and, as S-phase specific agents, their antitumor effect is maximized when they are administered in protracted schedules. The documented activity as single agents in many adult and pediatric malignancies has been followed by their use in combination with other anticancer agents. These studies have shown promising results, and have placed topotecan and irinotecan in the first line treatment for some malignancies. However, studies to better determine the optimal schedules and sequence of combinations are needed.

Gemcitabine plus vinorelbine in elderly or unfit patients with non-small cell lung cancer

Cisplatin-based combinations are efficacious in increasing the overall survival of patients with non-small cell lung cancer (NSCLC), but their toxicity makes them unsuitable for elderly and unfit patients. The primary objective of this non-randomized phase II study was to evaluate the feasibility and activity of the gemcitabine plus vinorelbine combination in previously untreated elderly and/or unfit patients with measurable stage III or IV NSCLC. Forty-three patients aged >/= 65 years or with contraindications against cisplatin treatment (36 males and seven females: median age 66 years; range 48-75: PS 0 = 11, PS 1 = 19, PS 2 = 13) received intravenous (i.v.) gemcitabine 1000 mg m(-2), followed by vinorelbine 25 mg m(-2)i.v. on day 1 and 8 every 21 days. Fifteen patients (34.9%) achieved partial remission (confidence interval: 27. 6-42.2%) for a median duration of 6 months; the median survival of these patients has not yet been reached. A further 15 had stable disease for a median of 4 months and a median survival of 7 months. The 10 patients (23.2%) who experienced disease progression had a median survival of 4 months. Three patients are not evaluable. The 1-year actuarial survival rate is 31.1%. The treatment was well tolerated: only 35% of the patients had grade 3 or 4 granulocytopenia on day 14, none experienced episodes of neutropenic fever, and there was no evidence of severe haematological toxicity upon recycling. Only 9% of the patients suffered from gastrointestinal toxicity (grade 3); increased but reversible transaminase levels were observed in 11.6%. In conclusion, the results of this phase II study show that the combination of gemcitabine and vinorelbine is active and well tolerated in NSCLC, and thus encourage its use in elderly or unfit patients.

Phase II trial of aminocamptothecin (9-AC/DMA) in patients with advanced squamous cell head and neck cancer

Fourteen patients with squamous cell carcinoma of the head and neck received 9-AC/DMA infusions of 850 mg/M2/day over 72 hours. Eligibility criteria included good performance status, advanced disease incurable by conventional means, no prior treatment of metastatic disease, and measurable lesions for objective response assessment. The infusions were repeated at 21 day intervals until progression or prohibitive toxicity occurred. A median of 3 cycles (range 1-7) was given. No objective responses were observed. Median survival of the group was 6 months. Toxicity was hematologic which was modest and promptly reversible. 9-AC/DMA is inactive against this tumor type at the dose and schedule employed in this study.

Phase I and pharmacologic study of docetaxel and irinotecan in advanced non-small-cell lung cancer

PURPOSE

We conducted a phase I trial of docetaxel, a new antimicrotubule agent, combined with irinotecan (CPT-11), a topoisomerase I inhibitor. The aim was to determine the maximum-tolerated dose (MTD) of docetaxel combined with CPT-11, as well as the dose-limiting toxicities (DLTs) of this combination in advanced non-small-cell lung cancer (NSCLC) patients.

PATIENTS AND METHODS

Thirty-two patients with stage IIIB or IV NSCLC were treated at 4-week intervals with docetaxel (60 minutes, day 2) plus CPT-11 (90 minutes, days 1, 8, and 15). The starting doses of docetaxel/CPT-11 were 30/40 mg/m(2), and doses were escalated in 10-mg/m(2) increments until the MTD was reached.

RESULTS

The MTD of docetaxel/CPT-11 was 50/60 mg/m(2) (level 5A), or 60/50 mg/m(2) (level 5B). Neutropenia and diarrhea were the DLTs. CPT-11 did not affect the pharmacokinetics of docetaxel. There were 11 (37%) partial responses among 30 patients. The median survival time was 48 weeks, and the 1-year survival rate was 44.9%.

CONCLUSION

The combination of docetaxel and CPT-11 seems to be active against NSCLC, with acceptable toxicity. The recommended dose for phase II studies is 50 mg/m(2) of CPT-11 (days 1, 8, and 15) and 50 mg/m(2) of docetaxel (day 2) administered every 28 days.

Identification and characterization of a deletion mutant of DNA topoisomerase I mRNA in a camptothecin-resistant subline of human colon carcinoma

In previous studies, we established two camptothecin (CPT)-resistant sublines, HT-29 / CPT and St-4 / CPT, from the human colon cancer cell line HT-29 and the human stomach cancer cell line St-4, respectively. Cellular contents of DNA topoisomerase I (topo I) in the resistant cells were eight-fold less than those in the corresponding parental lines. In this study, we have shown expression of two species of the TOP1 mRNA in HT-29 / CPT. The longer mRNA (4.0 kb) is the wild-type TOP1 mRNA, and the shorter mRNA (3.3 kb) proved to have a deletion of 672 bp (nucleotides 58 - 729 or 59 - 730) that caused the in-frame deletion of amino acids 20 - 243 of human topo I. The deleted region is identical to exons 3 - 9 of the TOP1 gene. The expression level of the 3.3-kb mRNA was similar to that of the wild-type mRNA in HT-29 / CPT. St-4 / CPT expressed only the wild-type TOP1 mRNA in lesser amounts than did St-4. Mouse NIH3T3 cells transfected with the wild-type TOP1 cDNA showed higher sensitivity to CPT than the parental cells, whereas those transfected with the deleted TOP1 cDNA showed levels similar to those of the parental cells. Expression of the exogenous TOP1 mRNA was confirmed; however, expression of the truncated topo I was not detected in cells transfected with the deleted TOP1 cDNA. These results suggest that the expression of the deleted TOP1 mRNA led to the low expression of CPT-sensitive topo I in the resistant cells.

The role of new agents in advanced non-small-cell lung carcinoma

Over the past 5 to 7 years, new and promising systemic agents have entered the therapeutic armamentarium in the treatment of advanced non-small-cell lung cancer. In particular, the taxanes, irinotecan, vinorelbine, and gemcitabine, have each been shown to perturb the natural history of this disease. In combination with cisplatin, these agents have yielded improvements in response rates and in survival, compared with either cisplatin alone or with older platinum combinations, with consistent 1-year survival rates of 30% to 40% or more and response rates exceeding 25%. Other factors may also be responsible for improved survival rates, including patient selection, improved supportive care, and more extensive screening procedures, such as CT and positron emission tomography, which have resulted in stage migration. Future directions will focus on the role of nonplatinum combinations, particularly in the elderly and in patients with compromised performance status; salvage therapy in patients with intact performance status; quality of life and quality adjusted survival; and the role of new biologic agents, which alter the tumor milieu and may be readily integrated into standard cytotoxic regimens. Except for unfit or unwilling patients, there is no room for therapeutic nihilism.

In vitro augmentation of antitumor effect in combination with CPT-11 and CDDP for human colorectal cancer

BACKGROUND AND OBJECTIVES

Irinotecan hydrochloride (CPT-11) is one of the camptothecin analogues that has shown a broad spectrum of strong antitumor effectiveness against various cancers, including colorectal cancer. In order to promote the clinical response of chemotherapy for colorectal cancer using CPT-11, one of the most effective strategies is to use it in combination with other anticancer agents. In the present study, anticancer effects after combining CPT-11 and other antitumor agents were determined by a 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay of colorectal cancer cells, especially freshly isolated cancer cells.

METHODS

Freshly isolated cancer cells from 20 patients with colorectal cancer and the established colon cancer cell lines were used in this study. The augmentation of the antitumor effectiveness of 7-ethyl-10-hydroxy-CPT (SN-38) was analyzed in combination with other anticancer agents. Furthermore, the antitumor effectiveness using lower concentrations of anticancer agents was measured to understand the mechanism of the augmentation.

RESULTS

The percent inhibition of SN-38 in combination with cisplatin (CDDP) and mitomycin revealed a high anticancer effect compared with each anticancer agent alone for freshly isolated rectal cancer. CDDP also had a synergistic effect in combination with SN-38 according to the fractional product concept. At lower than plasma peak concentrations of SN-38, the anticancer effects were augmented in combination with lower concentrations of CDDP for freshly isolated colorectal cancer. This augmentation showed a strong synergistic effect.

CONCLUSIONS

These results may be supportive to ongoing clinical studies of chemotherapy by using CPT-11 and CDDP for advanced colorectal cancer.

pH-dependent uptake of irinotecan and its active metabolite, SN-38, by intestinal cells

Irinotecan (CPT-11) and its active metabolite, 7-ethyl-10-hydroxycamptothecin (SN-38), are believed to be reabsorbed by intestinal cells and to enter the entero-hepatic circulation, but there is little information to date. Our objective was to investigate the intestinal transport of CPT-11 and SN-38 in correlation with their associated cytotoxicity. Using either isolated hamster intestinal epithelial cells or/and human colon carcinoma HT29 cells, the uptake rates of [(14)C]CPT-11 and [(14)C]SN-38, both as respective non-ionic lactone form at acidic pH and anionic carboxylate form at basic pH, were investigated by the rapid vacuum filtration technique. The effect of physiologic intestinal luminal pH (6.2-8.0) on the uptake rate and cytotoxicity of SN-38 were estimated by the above method and the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, respectively. The lactone forms of CPT-11 and SN-38 were transported passively, while the respective carboxylate form was absorbed actively. Uptake rates of both lactones were significantly higher than those of their carboxylates. Under physiologic pH, the respective uptake rates of CPT-11 and SN-38 were pH sensitive and decreased significantly by around 65%, at pH greater than 6.8. Furthermore, with decreasing pH, a higher uptake rate of SN-38 into HT29 cells correlates with a greater cytotoxic effect (r = 0.987). CPT-11 and SN-38 have absorption characteristics of weakly basic drugs such as short-chain fatty acids, suggesting that alkalization of the intestinal lumen may be critical to reduce their reabsorption and associated side effects.

Phase II study of irinotecan plus cisplatin in patients with advanced non-small-cell lung cancer

PURPOSE

To evaluate the antitumor efficacy and safety of a combination of irinotecan (CPT-11) and cisplatin in patients with inoperable non-small-cell lung cancer (NSCLC). A secondary objective was to characterize the pharmacokinetics and pharmacodynamics of CPT-11 and its active metabolite, SN-38.

PATIENTS AND METHODS

Patients with stage IIIB or IV NSCLC were treated with repeated 4-week courses comprising CPT-11 (60 mg/m(2)) administered on days 1, 8, and 15, and a single dose of cisplatin (80 mg/m(2)) after CPT-11 administration on day 1.

RESULTS

Fifty-two patients were enrolled, including 33 men and 19 women. The median age was 61 years (range, 29 to 79 years). Southwest Oncology Group performance status was 0 in 12 patients, 1 in 32 patients, and 2 in eight patients. Eleven and 41 patients had stage IIIB and IV disease, respectively. Objective responses occurred in 28.8% of patients (15 of 52; 95% confidence interval, 16.5% to 41.2%). The median survival duration was 9.9 months (range, 1.6 to 30.8 months). The 1-year survival rate was 37%. Grade 3/4 adverse events consisted primarily of nausea (32. 7% ) or vomiting (13.5%), late-onset diarrhea (17.3%), and neutropenia (46.1%). The study design led to preferential modification of CPT-11 doses, resulting in CPT-11 dose attenuations to < or = 40 mg/m(2) in the majority of patients (31 of 52; 60%), whereas dose reductions of cisplatin were uncommon. CPT-11 pharmacokinetic parameters were comparable to those reported previously in single-agent studies.

CONCLUSION

CPT-11/cisplatin is an active combination regimen with manageable toxicity in the therapy of stage IIIB/IV NSCLC. Future studies should be designed with schedules and dose modification provisions that avoid unnecessary CPT-11 dose reductions to exploit more directly the therapeutic synergy of these agents.

Second-line chemotherapy with weekly cisplatin and irinotecan in patients with refractory lung cancer

Cisplatin and irinotecan are reported to act synergistically. The authors have conducted a phase II trial combining cisplatin and irinotecan in patients with refractory lung cancer to evaluate the activity and safety of the regimen. Twenty-one patients, who had not responded to prior platinum-based chemotherapy, were entered into the study. Both cisplatin (30 mg/m2) and irinotecan (60 mg/m2) were administrated on days 1, 8, and 15, and the regimen was repeated every 28 days. There were six partial responses, and the response rate was 29% (95% confidence interval, 11.3%-52.2%). The median survival time of all patients was 32 weeks, and 1-year and 2-year survival rates were 43% and 11%, respectively. Major toxicities were hematologic; leukopenia of grades 3 and 4 developed in 43% patients, anemia developed in 38%, and thrombocytopenia developed in 19%. One notable nonhematologic toxicity was diarrhea; which was grade 3 in 38%. The weekly chemotherapy combining cisplatin and irinotecan was active against lung cancer, which is refractory to platinum-based chemotherapy. However, skips of drug administration or dose reduction were necessary in 76% patients during two courses of planned administration, though the ratio of actual dose to scheduled dose was 81%. Dose modification would be necessary to yield better results by this weekly chemotherapy.

Anticancer drug design based on plant-derived natural products

This review article focuses on recent research in my laboratory on various classes of compounds that possess potent antitumor activity. These compounds were obtained by bioactivity- and mechanism of action-directed isolation and characterization coupled with rational drug design-based modification and analog synthesis. Structural modification, structure-activity relationship, and mechanism of action studies will be discussed.

Phase II trial of docetaxel with dexamethasone premedication in patients with advanced non-small cell lung cancer: the Canadian experience

We performed a Phase II trial to evaluate the activity and tolerability of docetaxel as a single agent in the treatment of advanced non-small cell lung cancer (NSCLC). Forty-four patients with metastatic and/or locally advanced NSCLC received i.v. docetaxel 100 mg/m2 every 3 weeks for a median of 4 (range 1-11) cycles. All patients received premedication with oral dexamethasone 8 mg twice daily for 5 days starting the day before chemotherapy. Seven partial responses were observed among 35 evaluable patients, and the overall response rate was 20% (95% CI 8-37). The median response duration was 5 months, median survival time was 10 months and the estimated 1-year survival rate was 42%. Treatment was generally well tolerated. Febrile neutropenia occurred in 10 patients (23%); neutropenic infection occurred in 4 patients, and led to 2 toxic deaths (both patients had borderline exclusion criteria). The corticosteroid premedication effectively reduced the overall incidence (34%) and severity (4% severe) of fluid retention, and delayed the median time to onset from cycle 4 to cycle 7. This study shows the promising efficacy of docetaxel as monotherapy in advanced NSCLC, and combination chemotherapy regimens incorporating docetaxel are now being evaluated in this clinical setting.

Direct translation of a protracted irinotecan schedule from a xenograft model to a phase I trial in children

PURPOSE

In a preclinical model of neuroblastoma, administration of irinotecan daily 5 days per week for 2 consecutive weeks ([qd x 5] x 2) resulted in greater antitumor activity than did a single 5-day course with the same total dose. We evaluated this protracted schedule in children.

PATIENTS AND METHODS

Twenty-three children with refractory solid tumors were enrolled onto a phase I study. Cohorts received irinotecan by 1-hour intravenous infusion at 20, 24, or 29 mg/m(2) (qd x 5) x 2 every 21 days.

RESULTS

The 23 children (median age, 14.1 years; median prior regimens, two) received 84 courses. Predominant diagnoses were neuroblastoma (n = 5), osteosarcoma (n = 5), and rhabdomyosarcoma (n = 4). The dose-limiting toxicity was grade 3/4 diarrhea and/or abdominal cramps in six of 12 patients treated at 24 mg/m(2), despite aggressive use of loperamide. The maximum-tolerated dose (MTD) on this schedule was 20 mg/m(2)/d. Five patients had partial responses and 16 had disease stabilization. On day 1, the median systemic exposure to SN-38 (the active metabolite of irinotecan) at the MTD was 106 ng-h/mL (range, 41 to 421 ng-h/mL).

CONCLUSION

This protracted schedule is well tolerated in children. The absence of significant myelosuppression and encouraging clinical responses suggest compellingly that irinotecan be further evaluated in children using the (qd x 5) x 2 schedule, beginning at a dose of 20 mg/m(2). These results imply that data obtained from xenograft models can be effectively integrated into the design of clinical trials.

A dual topoisomerase inhibitor, TAS-103, induces apoptosis in human cancer cells

TAS-103 (6-[[2-(dimethylamino)ethyl]amino]-3-hydroxy-7H-indeno[2,1-c] quinolin-7-one dihydrochloride), a dual topoisomerase (topo) inhibitor, was developed as an anticancer agent by targeting topo I and topo II and has previously been shown to be effective against lung tumors. In this study, we investigated the cytotoxic activity of TAS-103 in various human cancer cell lines (including gastric, colon, squamous, lung, and breast cancer cells) and the induction of apoptosis by TAS-103. We next established stable transfectants of Bcl-2 in the gastric cancer cell line AZ521 and found that Bcl-2 blocked TAS-103-induced apoptosis. In addition, we demonstrated that the activities of ICE-like and CPP32-like proteases are involved in the signal transduction pathway of TAS-103-induced apoptosis. In summary, TAS-103 is a novel type of anticancer agent with a unique mechanism and could be useful as a lead compound for development of new drugs.

Induction platinum-based chemotherapy followed by radical hyperfractionated radiotherapy with concurrent chemotherapy in the treatment of locally advanced non-small-cell carcinoma of the lung

This study evaluated tolerance, local control, and short-term survival in patients with locally advanced non-small-cell lung carcinoma treated with induction chemotherapy followed by radical hyperfractionated radiotherapy with concurrent chemotherapy. Thirty-one patients with stage IIIa (N2) or IIIb tumors were treated with cis-platinum-based induction chemotherapy for 1 to 4 courses followed by radical hyperfractionated radiotherapy (69.6 Gy) with concurrent chemotherapy given at the beginning and end of radiotherapy. Induction chemotherapy produced no complete responses and 18 (58%) partial responses. After completion of radiotherapy, 4 patients had complete response (13%) and 23 patients (74%) partial response. The patterns of failure were as follows: intrathoracic, 6 patients (22%); intrathoracic + distant metastasis, 6 patients (22%); distant metastasis without thoracic failure, 5 patients (19%). Six patients of the 12 with intrathoracic failure experienced in-field radiotherapy pure local failure. At the time of this analysis, 10 patients were alive and well (4 complete and 6 partial responders). Actuarial survival projected at 39 months is 35%. No benefit was observed for those patients responding to induction chemotherapy. Toxicity was as follows: grade III neutropenic fever in 4 patients (13%), grade IV neutropenia in 13 patients (42%), pneumonia in 6 patients (19%), grade III esophagitis in 4 patients (13%) and severe clinical pneumonitis in 1 patient (3%). Induction chemotherapy followed by chemoradiotherapy is feasible, and the preliminary results are encouraging. Complete response after radiotherapy appeared to be related to short-term disease-free survival, and decisions based on the response to chemotherapy may be equivocal.

High-performance liquid chromatographic method for the simultaneous determination of the camptothecin derivative irinotecan hydrochloride, CPT-11, and its metabolites SN-38 and SN-38 glucuronide in rat plasma with a fully automated on-line solid-phase extraction system, PROSPEKT

We established a high-performance liquid chromatography (HPLC) method for the simultaneous determination of the camptothecin (CPT) derivative, irinotecan hydrochloride (CPT-11) and its metabolites, 7-ethyl-10-hydroxycamptothecin (SN-38) and SN-38 glucuronide (SN-38G) in rat plasma with a fully automated on-line solid-phase extraction system, PROSPEKT. Plasma samples were pretreated with 0.146 M H3PO4 to inactivate carboxylesterase and beta-glucuronidase in rat plasma, and added with the internal standard solution (0.146 M H3PO4 containing 1 microgram/ml CPT) and then analyzed. The method was validated for CPT-11 (5 to 25,000 ng/ml), SN-38 (5 to 2500 ng/ml) and SN-38G (2.5 to 500 ng/ml). This method enabled the determination of many samples within a relatively short time with easy sample preparation. It also had four advantages compared with conventional determination methods, i.e. automation of a complicated sample preparation, time-saving by the simultaneous determination of three compounds, the direct determination of SN-38G, and the small amount of plasma required for the determination.

Phase I/II study of weekly irinotecan and concurrent radiation therapy for locally advanced non-small cell lung cancer

A study was undertaken to determine the maximum tolerated dose, the dose-limiting toxicities, and the response rate of irinotecan administered weekly with concurrent thoracic radiation therapy in patients with locally advanced non-small-cell lung cancer. In a phase I/II clinical trial, patients with histologically documented, surgically unresectable stage IIIA or IIIB non-small cell lung cancer (NSCLC) were enrolled. Irinotecan was administered as a 90 min intravenous infusion once weekly for 6 weeks. The starting dose was 30 mg m(-2) and dose escalation was done in 15 mg m(-2) increments. Dose-limiting toxicity was defined as grade 3 nonhaematologic toxicity (excluding nausea, vomiting and alopecia) or grade 4 haematologic toxicity according to the WHO criteria. Radiation was delivered to the primary tumour and regional lymph nodes (40 Gy), followed by a boost to the primary tumour (20 Gy). Twenty-seven patients were entered into this study at three irinotecan dose levels (30, 45 and 60 mg m(-2)). Twenty-six eligible patients were evaluated for toxic effects and clinical outcome. Severe oesophagitis, pneumonitis, and diarrhoea occurred at 45 and 60 mg m(-2). Three of the five patients given 60 mg m(-2) developed grade 3 or 4 oesophagitis and pneumonitis. In addition, one patient died of pneumonitis after completing therapy at 45 mg m(-2) in the phase II study. The objective response rate was 76.9% (95% CI, 53.0-88.9%). Oesophagitis, pneumonitis, and diarrhoea are the dose-limiting toxicities of weekly irinotecan combined with thoracic irradiation. The maximum tolerated dose and the dose for the phase II study were 60 and 45 mg m(-2) wk(-1), respectively. This combined therapy for locally advanced non-small cell lung cancer is promising and shows acceptable toxicity.

In vitro sensitivity of fresh ovarian carcinoma specimens to CPT-11 (irinotecan)

OBJECTIVE

Irinotecan (CPT-11) is a DNA topoisomerase I inhibitor which has shown activity in vitro against several cancer cell lines and some promising clinical responses in phase I and II trials in various solid tumors. The cytotoxicity of CPT-11 on human ovarian epithelial malignancies was tested in vitro utilizing the ATP chemosensitivity assay. Flow cytometry was also performed on the fresh carcinoma specimens.

METHODS

Fresh tumor samples were obtained at laparotomy from 20 patients with primary adenocarcinoma of the ovary and 1 patient with heavily pretreated recurrent ovarian carcinoma. Tumors were plated in an in vitro system and treated with varying doses of both CPT-11 and its active metabolite SN-38 (7-ethyl-10-hydroxycamptothecin), in addition to a panel of standard chemotherapeutic agents used in treating ovarian cancer. On the sixth day after incubation, ATP levels in remaining cells were measured using a luminometer as an indication of the amount of cell kill compared to untreated controls.

RESULTS

Twelve of the 21 tumors were evaluable for a response to CPT-11. Of the 12 tumors tested, 7 were found to have median effect doses of CPT-11 significantly under the clinically achievable peak plasma concentration (range 1.00 x 10(-4) to 44.67 microM) and 11 of the 12 tumors showed sensitivity to the active metabolite SN38 with median effect doses ranging from 2.00 x 10(-4) to 0.147 microM. Some of these tumors showed resistance to the standard agents, such as platinum, based on our assay. The heavily pretreated recurrent tumor tested was very sensitive to both CPT-11 and SN38 by our assay. The results of flow cytometry showed that the tumors were composed of heterogeneous populations of cells with mean S phase fractions varying from 7.0 to 17.3%. The only tumor not sensitive to SN38 showed the highest mean S phase activity of 17.3%.

CONCLUSIONS

Overall, these results suggest that CPT-11 deserves further investigation as a clinically useful chemotherapeutic agent for ovarian cancer.

Fractionated administration of irinotecan and cisplatin for treatment of lung cancer: a phase I study

A combination chemotherapy of irinotecan (CPT-11) and cisplatin (CDDP) has been reported to be active for lung cancer. In the previous trial, however, diarrhoea and leucopenia became the major obstacle for sufficient dose escalation of CPT-11 to improve the treatment outcome. We conducted a phase I study to investigate whether the fractionated administration of CDDP and CPT-11 at escalated dose was feasible and could improve the treatment outcome. Twenty-four previously untreated patients with unresectable non-small-cell lung cancer (NSCLC) or extensive disease of small-cell lung cancer (SCLC) were eligible. Both CDDP and CPT-11 were given on days 1 and 8, and repeated every 4 weeks. The dose of CDDP was fixed at 60 mg m(-2) and given by 1-h infusion before CPT-11 administration. The starting dose of CPT-11 was 40 mg m(-2), and the dose was escalated by an increase of 10 mg m(-2). The maximally tolerated dose of CPT-11 was determined as 60 mg m(-2) because grade 4 haematological or grade 3 or 4 non-haematological toxicities developed in six patients out of 11 patients evaluated. Diarrhoea became a dose-limiting toxicity. The objective response rates were 76% for NSCLC and 100% for SCLC. The recommended dose of CPT-11 and CDDP in a phase II study will be 50 mg m(-2) and 60 mg m(-2) respectively.

Hyperthermic modulation of SN-38-induced topoisomerase I DNA cross-linking and SN-38 cytotoxicity through altered topoisomerase I activity

The effect of different temperatures (37-42.5 degrees C) on SN-38 (the active metabolite of CPT-11) cytotoxicity was examined in the human lung carcinoma cell lines H460 and Calu-6 as well as the murine fibrosarcoma cell line L929. The cytotoxicity of SN-38, determined by MTT cell survival assay, was significantly increased in each cell line in combination with 41.8 degrees C hyperthermia (x60-120 min); the combination of SN-38 with 40.5 degrees C and 42.5 degrees C, however, was unchanged compared to 37 degrees C. Determination of topoisomerase (Topo) I DNA cross-linking in Calu-6 cells and L929 cells after treatment with SN-38 showed the same temperature profile as seen in the cell-survival assays with increased Topo I DNA cross-linking after treatment with the combination of SN-38 and 41.8 degrees C hyperthermia and unchanged Topo I DNA cross-linking at 40.5 degrees C and 42.5 degrees C. To test the hypothesis that increased Topo I DNA cross-linking and SN-38 cytotoxicity at 41.8 degrees C is caused by hyperthermia-modulated changes in Topo I activity, catalytic activity of Topo I extracted from each cell line and of purified human Topo I was determined at 20-42.5 degrees C. Topo I activity was found to be gradually increased with rising temperatures, resulting in significantly higher activity at 41.8 degrees C compared to 37 degrees C; further increase of temperature past 41.8 degrees C decreased Topo I activity back to levels found at 37 degrees C. Our data are used to explain a series of events resulting in hyperthermic enhancement of Topo I DNA cross-linking and SN-38 cytotoxicity in combination with 41.8 degrees C hyperthermia via increased Topo I activity.

Irinotecan: a new antineoplastic agent for the management of colorectal cancer

OBJECTIVE

To review the pharmacologic, pharmacokinetic, therapeutic, and safety aspects of irinotecan, a new antineoplastic agent, and to assess its role in the treatment of colorectal and lung cancer.

DATA SOURCES

English-language articles from the MEDLINE database, January 1990-March 1998; Pharmacia & Upjohn Company; published articles and meeting abstracts.

STUDY SELECTION

Studies in humans with cancer, clinical case reports, and open clinical studies were reviewed. Efficacy studies were limited to trials with at least 20 evaluable patients.

DATA EXTRACTION

Relevant data were extracted from published reports and abstracts.

DATA SYNTHESIS

Irinotecan is an effective agent for the treatment of advanced colorectal cancer. It demonstrates significant activity as a first-line agent and in patients with disease that is refractory to fluorouracil-containing regimens. Activity against lung cancer has also been demonstrated. Limited data indicate activity against cancers of the ovary, cervix, stomach, and in non-Hodgkin's lymphomas. Major toxicity consists of myelosuppression and diarrhea.

CONCLUSIONS

Irinotecan is a useful addition to the antineoplastic drug family and offers significant efficacy for treatment of patients with fluorouracil-refractory colorectal cancer.

Results of topotecan single-agent therapy in patients with myelodysplastic syndromes and chronic myelomonocytic leukemia

The activity of topotecan was evaluated in patients with myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML). Sixty patients with a diagnosis of MDS (n = 30) or CMML (n = 30) were treated. Their median age was 66 years, with 50 patients (83%) being over 60 years of age at time of study entry. Chromosomal abnormalities were present in 50% of patients and thrombocytopenia of less than 50 x 10(9)/L in 50%. Topotecan was administered as 2 mg/m2 by continuous infusion over 24 hours daily for five days (10 mg/m2 per course) every 4 to 6 weeks for two courses, then at maximum tolerated dose level (1-2 mg/m2 by continuous infusion over 24 hours daily for five days) once every 4-8 weeks for a maximum of 12 courses. Evaluation of outcome and of differences among subgroups was performed according to standard methods; the criteria for response were those used for acute leukemia. Nineteen patients (31%) achieved a complete response (CR). A CR was achieved in 11 of 30 patients with MDS (37%) and in eight of 30 with CMML (27%). A CR was achieved in 10 of 23 patients with previously untreated MDS (43%). Eight of 11 patients who presented with cytogenetic abnormalities (five of which involved chromosome 5 and/or 7 abnormalities) and achieved CR, were evaluated cytogenetically in CR: all were cytogenetically normal in CR. Characteristics associated with a higher CR rate were lack of previous chemotherapy, absence of ras oncogene mutations, and presence of less than 10% monocytes in either peripheral blood or bone marrow. In contrast, CR rates were similar by different agent groups, by different karyotype abnormalities, and by other pre-therapy peripheral blood counts. Non-myelosuppressive side effects were mucositis in 67% of patients (severe [grade 3-4] 23%), diarrhea in 38% (severe 17%), and nausea and vomiting in 28% (severe 5%). Febrile episodes during neutropenia occurred in 85% of patients and documented infections in 47 %. Mortality in the first four weeks was 20%. With a median follow-up duration of 31 months, the 12 month survival rate was 38%, median survival time 10.5 months, and median remission duration 7.5 months. In summary, topotecan has significant single-agent activity in MDS and CMML. Complete responses associated with topotecan therapy often involve the disappearance of abnormal, poor-prognosis karyotypes, which is particularly encouraging. Future strategies to optimize topotecan's role include combination regimens with topoisomerase II reactive agents, cytarabine, or hypomethylating agents (azacytidine and decitabine).

Characterization of a human small-cell lung cancer cell line resistant to a new water-soluble camptothecin derivative, DX-8951f

DX-8951f, a water-soluble and non-pro-drug analogue of camptothecin, exhibits a strong inhibitory action on DNA topoisomerase I (Topo I) and in vitro cytotoxicity against various human cancer cell lines. In order to elucidate the mechanisms of its cytotoxicity, we established a DX-8951f-resistant cell line, SBC-3/DXCL1, from human small cell lung cancer cells (SBC-3) by stepwise exposure to DX-8951f. SBC-3/DXCL1 cells were approximately 400 times more resistant to DX-8951f than parent cells. The SBC-3/DXCL1 cells showed a high degree of cross-resistance to other Topo I inhibitors such as CPT-11, SN-38 and camptothecin, but not to non-Topo I targeting agents such as cisplatin, adriamycin, etoposide, and vincristine. The mechanisms of resistance of SBC-3/DXCL1 cells to DX-8951f were examined. Intracellular accumulation of DX-8951f by SBC-3 and SBC-3/DXCL1 cells did not differ significantly. Although the Topo I activity of nuclear extracts obtained from SBC-3/DXCL1 cells was the same as that of the parent cells, the Topo I of SBC-3/DXCL1 cells was resistant to the inhibitory effects of DX8951f and SN-38. Immunoblotting using anti-Topo I antibody demonstrated similar protein levels of Topo I in SBC-3 and SBC-3/DXCL1 cells. The active Topo I protein of SBC-3/DXCL1 was eluted by a high concentration of NaCl (0.4 N) compared with that of SBC-3 (0.3 N). DX-8951f stabilized the DNA-Topo I cleavable complex from SBC-3 cells, as measured by Topo I-mediated cleavage assay. In SBC-3/DXCL1 cells, DX-8951f also stabilized the DNA-Topo I complex, but with a 10-fold lower efficiency. These results suggest that a qualitative change in Topo I contributes, at least partially, to the resistance to DX-8951f in SBC-3/DXCL1 cells. Therefore, SBC-3/DXCL1 cells may have a unique mechanism of resistance to Topo I-directed antitumor drugs.

Response rate as an endpoint for evaluating new cytotoxic agents in phase II trials of non-small-cell lung cancer

BACKGROUND

Response rate (RR) has been used as a defining endpoint of new-agent phase II trials for non-small-cell lung cancer (NSCLC). However, tumor responses to chemotherapy do not always result in prolonged survival of patients with this disease.

DESIGN

Single-agent phase II trials were identified by a MEDLINE search of the period from 1976 to 1995. Associations between RR, median survival time (MST) and characteristics of patients who entered the trial, including tumor extent, performance status and prior chemotherapy, were studied by using the logistic regression model.

RESULTS

A total of 183 treatment arms in 176 trials (including 10 randomized phase II trials) were identified. The overall RR in the 6768 evaluable patients was 11%. Eleven drugs, cisplatin, epirubicin, ifosfamide, edatrexate, irinotecan, vinorelbine, docetaxel, paclitaxel, etoposide, vindesine, and 254-S, produced a RR of more than 20%. An MST of eight months or longer was obtained with 12 drugs, but there were cases in which no objective responses were produced by these drugs. MST was correlated with RR (r = 0.504, P < 0.0001), but ranged broadly at a given level of RR. Multiple linear regression analysis showed a significant correlation between RR and MST (regression coefficient = 0.60, P = 0.00003) after adjustment for other variables.

CONCLUSIONS

RR was significantly correlated with MST in single-agent phase II trials for NSCLC, but there is room for further consideration of the endpoint of these trials.

Clinical applications of the camptothecins

The camptothecin topoisomerase I-targeting agents are new class of antitumor drugs with demonstrated clinical activity in human malignancies, such as colorectal cancer and ovarian cancer. Currently, irinotecan and topotecan are the most widely used camptothecin analogs in clinical use and clinical trials are ongoing to better characterize their spectra of clinical activity, to determine their optimal schedules of administration and to define their use in combination with other chemotherapeutic agents. Newer camptothecin analogs in clinical development, such as 9-aminocamptothecin, 9-nitrocamptothecin, GI147211 and DX-8951f, are also being studied to determine if they have improved toxicity and efficacy profiles compared with existing analogs. Other potential clinical applications include the use of camptothecin derivatives as radiation sensitizers or as antiviral agents. The successful development of the camptothecins as antitumor agents highlights the importance of topoisomerase I as a target for cancer chemotherapy.