Phase I study of paclitaxel and topotecan in patients with advanced tumors: a cancer and leukemia group B study

Silver Nanoparticles Potentiates Cytotoxicity and Apoptotic Potential of Camptothecin in Human Cervical Cancer Cells

Silver nanoparticles (AgNPs) are widely used metal nanoparticles in health care industries, particularly due to its unique physical, chemical, optical, and biological properties. It is used as an antibacterial, antiviral, antifungal, and anticancer agent. Camptothecin (CPT) and its derivatives function as inhibitors of topoisomerase and as potent anticancer agents against a variety of cancers. Nevertheless, the combined actions of CPT and AgNPs in apoptosis in human cervical cancer cells (HeLa) have not been elucidated. Hence, we investigated the synergistic combinatorial effect of CPT and AgNPs in human cervical cancer cells. We synthesized AgNPs using sinigrin as a reducing and stabilizing agent. The synthesized AgNPs were characterized using various analytical techniques. The anticancer effects of a combined treatment with CPT and AgNPs were evaluated using a series of cellular and biochemical assays. The expression of pro- and antiapoptotic genes was measured using real-time reverse transcription polymerase chain reaction. The findings from this study revealed that the combination of CPT and AgNPs treatment significantly inhibited cell viability and proliferation of HeLa cells. Moreover, the combination effect significantly increases the levels of oxidative stress markers and decreases antioxidative stress markers compared to single treatment. Further, the combined treatment upregulate various proapoptotic gene expression and downregulate antiapoptotic gene expression. Interestingly, the combined treatment modulates various cellular signaling molecules involved in cell survival, cytotoxicity, and apoptosis. Overall, these results suggest that CPT and AgNPs cause cell death by inducing the mitochondrial membrane permeability change and activation of caspase 9, 6, and 3. The synergistic cytotoxicity and apoptosis effect seems to be associated with increased ROS formation and depletion of antioxidant. Certainly, a combination of CPT and AgNPs could provide a beneficial effect in the treatment of cervical cancer compared with monotherapy.

Review : Topoisomerase I inhibitors: 1. Topotecan

Purpose. The primary objective of this article is to discuss the pharmacology, pharmacokinetics, clin ical use, and adverse effects of the approved topoisomerase I inhibitors. This is the first in a series of two articles and will focus on topotecan.

Data Sources. We reviewed the literature through a MEDLINE search of English language articles from 1985 through 1997. Relevant articles cited in the titles obtained from the MEDLINE search were also used. The following terms were used for purpose of conducting the MEDLINE search: topoisomerase inhibitors, topotecan, topo isomerase I, Hycamtin, SKF 104864.

Data Extraction. We reviewed the current literature in order to discuss the pharmacology, pharmacokinetics, clinical use, toxicity, drug inter actions, indications, formulation, dosage and ad ministration, and pharmaceutical issues surround ing the use of topotecan.

Data Synthesis. The topoisomerase I inhibi tors are new antineoplastic agents with a unique mechanism of action. Promising areas of applica tion include ovarian cancer, lung cancer, radiation sensitization, and refractory leukemias. Clinical tri als detailing its activity in these areas are pre sented.

A phase I study of paclitaxel, topotecan, cisplatin and Filgrastim in patients with newly diagnosed advanced ovarian epithelial malignancies: a Gynecologic Oncology Group study

OBJECTIVES

To determine a recommended dose level (RDL) of paclitaxel, cisplatin and topotecan in women with previously untreated epithelial ovarian or peritoneal cancer as a possible experimental arm in a future Gynecologic Oncology Group phase III study.

METHODS

Patients with newly diagnosed stage III or IV disease were treated with paclitaxel 175 mg/m2/3 h, followed 2 h later by cisplatin 50 mg/m2 on day 1. Topotecan was administered on consecutive days as a 30-minute infusion, beginning after cisplatin on day 1, receiving either 5 days beginning at 0.3 mg/m2 (cohort 1), or 3 days beginning at 0.5 mg/m2 (cohort 2). Treatment was given every 21 days for a maximum of 8 cycles.

RESULTS

Forty-five evaluable patients were enrolled in the two cohorts. Thrombocytopenia and prolonged neutropenia were the major dose-limiting toxicities. Dose-limiting neutropenia was seen at the first dose level, thus all subsequent dose escalations included Filgrastim. The RDL of cohort 1 was paclitaxel 175 mg/m2/3 h, cisplatin 50 mg/m2 and topotecan 0.5 mg/m2 daily x 5 with Filgrastim. The RDL of cohort 2 was paclitaxel 175 mg/m2/3 h, cisplatin 50 mg/m2 and topotecan 0.75 mg/m2 daily x 3 with Filgrastim.

CONCLUSION

In women with previously untreated epithelial ovarian or peritoneal cancer the combination of paclitaxel, cisplatin and topotecan is feasible. However, this treatment requires the use of Filgrastim and attenuated dosing of topotecan in both a 5-day and 3-day topotecan infusion schedule.

Phase I North Central Cancer Treatment Group Trial-N9923 of escalating doses of twice-daily thoracic radiation therapy with amifostine and with alternating chemotherapy in limited stage small-cell lung cancer

PURPOSE

The primary goal was to identify the maximum tolerable dose (MTD) of thoracic radiation therapy (TRT) that can be given with chemotherapy and amifostine for patients with limited-stage small-cell lung cancer (LSCLC).

METHODS AND MATERIALS

Treatment began with two cycles of topotecan (1 mg/m(2)) Days 1 to 5 and paclitaxel (175 mg/m(2)) Day 5 (every 3 weeks) given before and after TRT. The TRT began at 6 weeks. The TRT was given in 120 cGy fractions b.i.d. and the dose escalation (from 4,800 cGy, dose level 1, to 6,600 cGy, dose level 4) followed the standard "cohorts of 3" design. The etoposide (E) (50 mg/day) and cisplatin (C) (3 mg/m(2)) were given i.v. before the morning TRT and amifostine (500 mg/day) was given before the afternoon RT. This was followed by prophylactic cranial irradiation (PCI). The dose-limiting toxicities (DLTs) were defined as Grade > or =4 hematologic, febrile neutropenia, esophagitis, or other nonhematologic toxicity, Grade > or =3 dyspnea, or Grade > or =2 pneumonitis.

RESULTS

Fifteen patients were evaluable for the Phase I portion of the trial. No DLTs were seen at dose levels 1 and 2. Two patients on dose level 4 experienced DLTs: 1 patient had a Grade 4 pneumonitis, dyspnea, fatigue, hypokalemia, and anorexia, and 1 patient had a Grade 5 hypoxia attributable to TRT. One of 6 patients on dose level 3 had a DLT, Grade 3 esophagitis. The Grade > or =3 toxicities seen in at least 10% of patients during TRT were esophagitis (53%), leukopenia (33%), dehydration (20%), neutropenia (13%), and fatigue (13%). The median survival was 14.5 months.

CONCLUSION

The MTD of b.i.d. TRT was 6000 cGy (120 cGy b.i.d.) with EP and amifostine.

The cancer and leukemia group B pharmacology and experimental therapeutics committee: a historical perspective

The Chemotherapy Committee of Cancer and Leukemia Group B (CALGB) was established in the mid-1970s to assemble a group of experts in cancer chemotherapy and pharmacology who could advise the CALGB disease committees about the optimal use of drugs in the fight against cancer and to provide quality assurance for the chemotherapy section of CALGB protocols. Chaired initially by Edward Henderson and then David Van Echo, the committee was also the repository of studies in diseases for which CALGB did not have a formal committee, such as testis cancer and sarcoma. In 1990, following the appointment of Richard Schilsky as Chair, the name of the committee was changed to the Pharmacology and Experimental Therapeutics (PET) Committee to reflect a more specific focus and scientific agenda (i.e., studies of chemotherapy pharmacology and development of new agents). Three PET Committee reference pharmacology laboratories (led by Merrill Egorin, Tony Miller, and Mark Ratain) were established to measure drug concentrations in biological fluids and to perform pharmacokinetic analyses. In addition, the PET Committee embarked on a number of multi-institution phase I studies. These phase I studies included studies of special populations, including the first prospective study of an anticancer agent (paclitaxel) in patients with hepatic dysfunction. In addition, the Committee studied a number of phase I combinations destined for phase II evaluation in disease-specific committees. Following Dr. Schilsky's election as CALGB Group Chair in 1994, Mark Ratain took over as Chair of the PET Committee and continued to emphasize population pharmacology as the primary theme of the Committee's research agenda. In addition, the PET Committee began to develop novel clinical trial designs, including the first completed randomized discontinuation trial of an antineoplastic agent. Most recently, the PET Committee has launched an ambitious research program in pharmacogenetics, facilitated in large part through the recruitment of Howard McLeod as Vice Chair. This area of research is a collaborative effort with the NIH Pharmacogenetics Research Network and has the potential to definitively address the hypothesis that germ line polymorphisms are a significant determinant of the toxicity and efficacy of anticancer therapy. It is anticipated that the results of the current studies will contribute significantly to the goal of individualizing cancer treatment.

A Phase II trial of paclitaxel and topotecan with filgrastim in patients with recurrent or refractory glioblastoma multiforme or anaplastic astrocytoma

PURPOSE

Therapy for high-grade gliomas remains unsatisfactory. Paclitaxel and topotecan have separately demonstrated activity against gliomas. We conducted a Phase II trial of these agents in combination with filgrastim (G-CSF) in patients with recurrent or refractory glioblastoma multiforme or anaplastic astrocytoma.

PATIENTS AND METHODS

Adult patients with radiographic evidence of recurrent or progressive tumor following primary therapy were eligible for study. Patients received paclitaxel 175 mg/m2 IV over 3 h on day 1 and topotecan 1.0 mg/m2 IV over 30 min on days 1-5. Filgrastim 5 microg/kg was given days 6-14 for neutrophil support. Treatment cycles were repeated every 21 days.

RESULTS

Twenty patients were enrolled on study, and seventeen were considered evaluable for response. Two patients (12/%) exhibited partial remission and seven patients (41/%) exhibited stable disease in response to therapy. Hematologic toxicity was common with 25 /% of patients experiencing grade III or IV leukopenia despite G-CSF support. Two patients died of infectious complications on protocol, prompting suspension of further accrual.

CONCLUSION

Paclitaxel and topotecan with G-CSF support exhibits modest activity in adults with recurrent or refractory glioblastoma and anaplastic astrocytoma. The significant hematotoxicity encountered, however, cannot justify further investigation of this combination in patients with high grade brain tumors.

Phase I evaluation of docetaxel and topotecan for patients with advanced solid tumors

BACKGROUND

The authors administered a combination of docetaxel and topotecan with granulocyte-colony-stimulating factor (G-CSF) support in a Phase I study to define the maximum tolerated dose (MTD) of this regimen.

METHODS

Patients with advanced-stage solid tumors were eligible for this trial if they had a Zubrod performance status of </= 2 and normal renal, hepatic, and bone marrow function. No previous therapy with taxanes or topoisomerase inhibitors was allowed. The authors administered both docetaxel and topotecan in a dose-escalated manner until the MTD was reached. Docetaxel was given on Day 1 of each cycle before topotecan, which was administered intravenously on Days 1-3. Granulocyte-colony-stimulating factor (G-CSF) support with 5 microg/kg subcutaneous injections was initiated on Day 4 and continued until the absolute granulocyte count recovered to 2000/microL. Treatment cycles were repeated every 21 days.

RESULTS

Of the 11 patients enrolled in the current study, all were evaluable for toxicity and 10 were evaluable for response. A median of three treatment cycles was received (range, one to nine treatment cycles). The dose-limiting toxicity was Grade 4 (according to the National Cancer Institute Common Toxicity Criteria for Adverse Events [version 2.0]). neutropenia with fever. The MTD was 75 mg/m2 of docetaxel on Day 1 and 1.4 mg/m2 of topotecan on Days 1-3. There was one complete response and one partial response in patients with nasopharyngeal carcinoma and one partial response in a patient with small cell lung carcinoma (SCLC). The response durations were 24 weeks, 29 weeks, and >/= 244 weeks, respectively. At the time of last follow-up, both patients with nasopharyngeal carcinoma were still alive at 241 weeks and 244 weeks, respectively.

CONCLUSIONS

This trial demonstrated that a regimen of docetaxel and topotecan with G-CSF support was generally well tolerated and had promising activity in patients with nasopharyngeal and SCLC.

A phase I study of sequential administration of escalating doses of intravenous paclitaxel, oral topotecan, and fixed-dose oral etoposide in patients with solid tumors

BACKGROUND

Based on preclinical findings and on the clinical antitumor efficacy of sequential paclitaxel/topotecan and topotecan/etoposide, the authors sought to define the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) associated with a sequential combination of paclitaxel, topotecan, and etoposide in patients with solid tumors.

METHODS

The MTDs were determined through standard dose escalation in cohorts of three patients. Patients with refractory solid tumors and performance status < or = 2 were treated with intravenous paclitaxel 50-110 mg/m(2) (Day 1), oral topotecan 0.5-2.0 mg/m(2) (Days 2-4), and oral etoposide 160 mg/m(2) (Days 5-7) during every 21-day cycle. For dose-limiting neutropenia, granulocyte-colony-stimulating factor (G-CSF) was administered on Day 8 in subsequent cohorts. Blood samples were obtained before treatment during Cycle 1 (Days 1, 2, and 5) for topoisomerase I assessment.

RESULTS

Twenty-eight patients received a combined total of 129 cycles. The MTDs were paclitaxel 80 mg/m(2), topotecan 1.5 mg/m(2), and etoposide 160 mg/m(2) without G-CSF. In minimally pretreated patients, G-CSF allowed paclitaxel dose escalation to 110 mg/m(2). Three patients (11%) had radiologic partial responses, and 4 patients (14%) had stable disease. Day 2 topoisomerase I levels increased by 2-15 times relative to baseline levels in 7 of 14 patients analyzed (50%).

CONCLUSIONS

The novel sequential combination that was evaluated generally was well tolerated and active in patients with refractory solid tumors. Based on hematologic DLTs, the authors recommend further evaluation of paclitaxel 110 mg/m(2), topotecan 1.5 mg/m(2), and etoposide 160 mg/m(2) with G-CSF support in minimally pretreated patients.

Sequential dose-dense paclitaxel followed by topotecan in untreated extensive-stage small-cell lung cancer: a Spanish Lung Cancer Group phase II study

BACKGROUND

Poor survival rates in extensive-stage small-cell lung cancer (SCLC) patients prompted us to evaluate a sequential dose-dense schedule of paclitaxel followed by topotecan.

PATIENTS AND METHODS

Forty-three patients with previously untreated, extensive-stage SCLC received three cycles of paclitaxel 250 mg/m(2) over 3 h every 14 days followed by three cycles of topotecan 2.5 mg/m(2) for 5 days every 21 days. Granulocyte colony-stimulating factor was given after every cycle. Patients progressing at any time and those not achieving complete response (CR) subsequently received four cycles of standard-dose etoposide-cisplatin.

RESULTS

A total of 118 cycles of paclitaxel were administered with minimal hematological toxicity. Grade 2/3 peripheral neuropathy was observed in 21% of patients. Response rate to paclitaxel was 48.8%, and 25.6% had stable disease (SD). Thirty-two patients achieving SD or response to paclitaxel subsequently received a total of 90 topotecan cycles. Topotecan-related toxicities included febrile neutropenia in 15.6% of patients with one toxic death, grade 3/4 anemia in 25% of patients and grade 3/4 thrombocytopenia in 31.3%. Non-hematological toxicities were mild. At completion of sequential paclitaxel-topotecan treatment the overall response rate was 55.8% (22 partial response, two CRs). Median survival for all patients was 10.5 months and median progression-free survival was 8.5 months.

CONCLUSIONS

Sequential treatment with dose-dense paclitaxel followed by topotecan is feasible despite significant hematological toxicity during topotecan treatment. This schedule is an active regimen in extensive-stage SCLC and merits further investigation.

Phase I study of paclitaxel and topotecan for the first-line treatment of extensive-stage small cell lung cancer

Extensive-stage small cell lung cancer (SCLC) is an aggressive disease with a median survival of approximately 8 months. Although current combination chemotherapy regimens provide high initial tumor response rates, they have not translated into large gains in survival. Topotecan and paclitaxel have nonoverlapping mechanisms of action and are active agents in SCLC. Additionally, these two agents demonstrate in vitro synergy in animal and human tumor models. We investigated the maximum tolerated dose of 3-day topotecan in combination with paclitaxel in previously untreated patients with extensive SCLC. Seventeen patients were enrolled in an open-label, phase I, dose-escalation study and were treated with intravenous paclitaxel 135-175 mg/m(2) over 1 hour on day 1, followed by intravenous topotecan 1.25-1.5 mg/m(2) over 30 minutes on days 1-3 of a 21-day course. Sixty-nine courses of therapy were administered with no delays due to hematologic toxicity. Prophylactic hematologic support was required for 24% of patients. The topotecan/paclitaxel combination was well tolerated, with 24%, 12%, and 6% of patients experiencing grade 3/4 neutropenia, anemia, or thrombocytopenia, respectively. Dose-limiting neutropenia was seen in three of five patients treated with topotecan 1.5 mg/m(2) and paclitaxel 175 mg/m(2). Therefore, topotecan 1.5 mg/m(2) with paclitaxel 135 mg/m(2) was determined to be the maximum tolerated dose. Of the 17 evaluable patients, 53% achieved a partial response and 18% achieved stable disease. In summary, we have identified a regimen of topotecan 1.5 mg/m(2) and paclitaxel 135 mg/m(2) that was well tolerated and active in this patient group. Additional studies of topotecan and paclitaxel at these dose levels are needed to fully elucidate the efficacy of this combination in extensive SCLC.

Sequential administration of cisplatin-etoposide followed by topotecan in patients with extensive stage small cell lung cancer. A multicenter phase II study

PURPOSE

To evaluate the activity of the sequential administration of cisplatin-etoposide (PE) followed by topotecan (TOP) in patients with extensive stage small cell lung cancer (SCLC).

PATIENTS AND METHODS

Previously untreated patients with extensive stage SCLC received 4 cycles of cisplatin 75 mg/m(2) IV on day 1 and etoposide 100 mg/m(2) IV on days 1-3 every 21 days followed by 4 cycles of TOP 1.5 mg/m(2) IV on days 1-5 every 21 days.

RESULTS

Thirty-eight patients were entered in the study. Their median age was 63 years and the performance status (WHO) was 0 for 5, 1 for 25 and 2 for 8 patients. All patients were evaluable for toxicity and 32 for response to PE and 25 to TOP. Of the 38 patients receiving PE, 1 (3%) patient achieved complete response (CR) and 17 (45%) partial responses (PR) for an overall response rate to PE of 47% (95% confidence interval: 36.7-68.5%). Four (23.5%) of the 17 patients with PR after PE, achieved CR with TOP. None of the patients with stable or progressive disease after PE responded to TOP. The response rate of the 27 patients receiving TOP following PE was 15% (95% confidence interval: 1.4-28.2%). After a median follow up of 9 months, the median duration of response was 6.5 months, the time to tumor progression 6.5 months, the median survival 8.5 months and the 1-year survival 34%. A total of 136 cycles of PE and 89 cycles of TOP have been administered with a median of 4 cycles/patient for each regimen. There were 2 toxic deaths after PE associated with grade IV febrile neutropenia. Treatment delays due to toxicity occurred in 17 (12%) cycles of PE and 20 (22%) cycles of TOP while doses were reduced in 7 (5%) and 4 (4%) cycles, respectively. Grade 3-4 neutropenia, thrombocytopenia and febrile neutropenia occurred in 24, 2 and 3% of PE cycles and 21, 12 and 1% of TOP. Non-hematologic toxicity was mild. The delivered dose intensity was 100% for PE and 93% for TOP.

CONCLUSIONS

The sequential administration of TOP after PE is associated with manageable toxicity and may increase the number of CRs in patients with chemosensitive extensive stage SCLC. However, based on this data and the lack of survival benefit in a previous phase III study, the sequential regimen should not be used outside of a clinical trial.

Cisplatin-etoposide alternating with topotecan in patients with extensive stage small cell lung cancer (SCLC). A multicenter phase II study

PURPOSE

In order to investigate the feasibility of a potentially non-cross resistant drug regimen, we alternated cycles of cisplatin-etoposide with topotecan as front-line treatment in patients with extensive stage small cell lung cancer (SCLC).

PATIENTS AND METHODS

Thirty-six previously untreated patients with extensive stage SCLC received cisplatin 75 mg/m(2) IV on day 1 and etoposide 100 mg/m(2) IV on days 1-3 on cycles one, three, five and seven and topotecan 1.5 mg/m(2) IV on days 1-5 on cycles two, four, six and eight. Cycles were repeated every 21 days. Patients' median age was 60 years and performance status (WHO) was 0 for 13, 1 for 20 and 2 for three patients. All patients were evaluable for response and toxicity.

RESULTS

Five (14%) patients achieved a complete response and 18 (50%) a partial response for an overall response rate of 64% (95% confidence interval: 48.2-79.6%). After a median follow up of 10 months, the median duration of response was 5.5 months, the time to tumor progression 8 months and the probability of 1-year survival 48.9%. A total of 126 cycles of cisplatin-etoposide and 117 cycles of topotecan were administered with a median number of 4 cycles/patient for each regimen. There were no toxic deaths. Treatment delays due to toxicity occurred in 13 (10%) cycles after cisplatin-etoposide and 16 (14%) cycles after topotecan while doses were reduced in seven (6%) and five (4%) cycles, respectively. Grade 3-4 neutropenia, thrombocytopenia and febrile neutropenia complicated 13, 1 and 3% of cisplatin-etoposide cycles and 28, 6 and 1% of topotecan, respectively. Non-hematologic toxicity was mild. The delivered dose intensity was 96% for cisplatin and etoposide and 98% for topotecan.

CONCLUSIONS

The alternating administration of cisplatin-etoposide and topotecan is a feasible, active and well-tolerated regimen in patients with extensive stage SCLC.

Increased oral bioavailability of topotecan in combination with the breast cancer resistance protein and P-glycoprotein inhibitor GF120918

PURPOSE

We discovered that breast cancer resistance protein (BCRP), a recently identified adenosine triphosphate-binding cassette drug transporter, substantially limits the oral bioavailability of topotecan in mdr1a/1b(-/-) P-glycoprotein (P-gp) knockout and wild-type mice. GF120918 is a potent inhibitor of BCRP and P-gp. The aim was to increase the bioavailability of topotecan by GF120918.

PATIENTS AND METHODS

In cohort A, eight patients received 1.0 mg/m(2) oral topotecan with or without coadministration of one single oral dose of 1,000 mg GF120918 (day 1 or day 8). In cohort B, eight other patients received 1.0 mg/m(2) intravenous topotecan with or without 1,000 mg oral GF120918 to study the effect of GF120918 on the systemic clearance of topotecan.

RESULTS

After oral topotecan, the mean area under the plasma concentration-time curve (AUC) of total topotecan increased significantly from 32.4 +/- 9.6 microg.h/L without GF120918 to 78.7 +/- 20.6 microg.h/L when GF120918 was coadministered (P =.008). The mean maximum plasma concentration of total topotecan increased from 4.1 +/- 1.5 microg/L without GF120918 to 11.5 +/- 2.4 microg/L with GF120918 (P =.008). The apparent bioavailability in this cohort increased significantly from 40.0% (range, 32% to 47%) to 97.1% (range, 91% to 120%) (P =.008). Interpatient variability of the apparent bioavailability was 17% without and 11% with GF120918. After intravenous administration of topotecan, coadministration of oral GF120918 had a small but statistically significant effect on the AUC and systemic clearance of total topotecan but no statistically significant effect on maximum plasma concentration and terminal half-life of total topotecan.

CONCLUSION

Coadministration of the BCRP and P-gp inhibitor GF120918 resulted in a significant increase of the systemic exposure of oral topotecan. The apparent oral bioavailability increased from 40.0% without to 97.1% with GF120918.

Novel Doublets in Extensive-Stage Small-Cell Lung Cancer: A Randomized Phase II Study of Topotecan Plus Cisplatin or Paclitaxel (CALGB 9430)

Chemotherapy for extensive-stage small-cell lung cancer (E-SCLC) produces high response rates and improved survival but few cures. We tested three new regimens for E-SCLC that might merit further investigation in a subsequent phase III trial. Cancer and Leukemia Group B 9430 was a randomized phase II study evaluating 4 treatment arms in 57 evaluable, previously untreated E-SCLC patients. Each arm consisted of the following: Arm 1: cisplatin plus topotecan; Arm 2: cisplatin plus paclitaxel; Arm 3: paclitaxel 230 mg/m2 plus topotecan; and Arm 4: paclitaxel 175 mg/m2 plus topotecan. Because of an accrual time difference, Arm 2 will not be discussed in this manuscript. Arm 1 (12 patients) produced 1 complete response (CR, 8%) and an overall response rate (ORR) of 42%. Toxicity was excessive, with 3 deaths (25%). Arm 3 (13 patients) produced no CRs, 7 partial responses (PRs, 54%), median survival of 13.8 months, and failure-free survival (FFS) of 7.41 months, with 3 toxic deaths (25%). Among 32 evaluable patients on Arm 4, there were 2 CRs (6%) and 20 PRs (63%) for an ORR of 69%, median survival of 9.9 months, FFS of 5.21 months, and 1-year survival of 40%. There was 1 possible treatment-related death (3%). Topotecan plus cisplatin, in the doses and schedule employed, produced excessive toxicity and modest efficacy in E-SCLC patients. Paclitaxel (230 mg/m2 on day 1) plus topotecan (1 mg/m2 on days 1-5) produced excessive toxicity that was ameliorated with an attenuated paclitaxel dose (175 mg/m2). With the latter regimen (Arm 4) in patients with a performance status of 0/1, CR rates, FFS, overall survival, and 1-year survival were similar to standard etoposide plus cisplatin chemotherapy. Further exploration of topoisomerase inhibitors and taxanes in SCLC patients is warranted.

Camptothecins

Camptothecin analogues and derivatives appear to exert their antitumour activity by binding to topoisomerase I and have shown significant activity against a broad range of tumours. In general, camptothecins are not substrates for either the multidrug-resistance P-glycoprotein or the multidrug-resistance-associated protein (MRP). Because of manageable toxicity and encouraging activity against solid tumours, camptothecins offer promise in the clinical management of human tumours. This review illustrates the proposed mechanism(s) of action of camptothecins and presents a concise overview of current camptothecin therapy, including irinotecan and topotecan, and novel analogues undergoing clinical trails, such as exatecan (DX-8951f), IDEC-132 (9-aminocamptothecin), rubitecan (9-nitrocamptothecin), lurtotecan (GI-147211C), and the recently developed homocamptothecins diflomotecan (BN-80915) and BN-80927.

Paclitaxel plus topotecan treatment for patients with relapsed or refractory aggressive non-Hodgkin's lymphoma

BACKGROUND

Used as single agents, paclitaxel and topotecan have demonstrated promising activity in treating patients with relapsed aggressive non-Hodgkin's lymphoma (NHL). We conducted a phase II clinical trial to investigate the activity and tolerability of the combination of both drugs.

PATIENTS AND METHODS

Patients with refractory or relapsed aggressive NHL who had previously been treated with a maximum of two prior chemotherapeutic regimens were given intravenous infusions of paclitaxel 200 mg/m2 over three hours on day one and topotecan 1 mg/m2 over 30 minutes daily from days one to five. All patients received daily subcutaneous injections of filgrastim (granulocyte colony-stimulating factor) 5 microg/kg starting 24 hours after the last dose of chemotherapy until neutrophil recovery. Treatments were repeated every three weeks for a maximum of six courses. Patients who achieved partial remission or complete remission (CR) after at least two courses were offered stem cell transplantation, if eligible.

RESULTS

Of the 71 patients eligible for this trial, 66 (93%) were evaluable for treatment response. The median age was 53 years (range 23 to 74 years). Thirty-six percent of the patients had previously been treated with ara-C/platinum-based regimens, and 48% failed to achieve CR after primary induction therapy. Sixty-seven percent of the patients had elevated lactate dehydrogenase levels at the time of treatment initiation. The overall response rate was 48% (95% confidence interval (95% CI): 36%-61%). Patients who had primary refractory disease had a response rate of 31%, compared with 65% for patients who did not. Similarly, the response rate of patients who failed to achieve CR after their most recent previous therapy was 37%, compared with a 65% response rate in patients who relapsed from a first or second CR. The median duration of response was six months. A total of 199 courses were given, with a median of three courses per patient. Neutropenia at levels < or = 500 leukocytes per microliter was observed after 32% of the courses, and thrombocytopenia at levels < or = 20,000 platelets per microliter was observed after 17% of the courses. Grade 3-4 neutropenic fever occurred after 6% of the courses. Non-hematologic toxic effects were predominantly grade 1-2.

CONCLUSION

The combination of paclitaxel and topotecan is an effective first or second line salvage therapy for patients with relapsed or refractory aggressive NHL who had prior anthracycline- or platinum-based chemotherapy.

Phase I dose escalation study of topotecan combined with alternating schedules of paclitaxel and carboplatin in advanced solid tumors

BACKGROUND

Combining topotecan with other cytotoxics has been problematic due to marrow suppression. A phase I trial was initiated to identify the optimal sequence and maximum-tolerated dose of topotecan in combination with paclitaxel and carboplatin.

PATIENTS AND METHODS

Patients with advanced cancer and performance status ECOG < or = 2. The starting dose was paclitaxel 175 mg/m2 day 1, carboplatin AUC 6.0 day 1, and topotecan 0.5 mg/m2 daily day 1-5 (early sequence). The next course of paclitaxel and carboplatin administration was delayed to day 5 (late sequence). Treatment was repeated every three weeks. After determining maximum-tolerated dose without cytokines, granulocyte colony-stimulating factor (G-CSF) was added and further dose escalation was pursued.

RESULTS

Fifty-one patients were entered; men: women ratio 30:21. Dose-limiting toxicity (DLT) for the early sequence was neutropenia at doses paclitaxel mg/m2/carboplatin AUC 5/topotecan mg/m2 (PCT) 175/5/0.75 for four to five days. DLT for the late sequence was neutropenia at PCT doses of 175/5/ 1.0 for four days. G-CSF 5 microg/kg subcutaneously starting day 6 permitted further topotecan dose escalation. After adding G-CSF, late sequence DLT was neutropenia at doses 175/5/1.25 for four days. Forty-six patients were evaluable for response and of those, there were thirteen partial responses.

CONCLUSIONS

The late sequence resulted in less toxicity and was better tolerated. The early sequence maximum-tolerated dose (MTD) was 175/6/0.5 for five days. The late sequence MTD was PCT 175/5/0.75 for five days. The late sequence MTD with G-CSF was 175/5/1.0 for four days. The recommended phase II PCT dose is the late sequence 175/5/1.0 for four days with G-CSF.

The relevance of drug sequence in combination chemotherapy

The concept of combining chemotherapeutic agents to increase the cytotoxic efficacy has evolved greatly over the past several years. In the past, the rationale for combination chemotherapy centered on attacking different biochemical targets, overcoming drug resistance in heterogenous tumors, and increasing the dose-density of combination chemotherapy to take advantage of tumor growth kinetics. The overall goal was to improve clinical efficacy with acceptable clinical toxicity. It is now apparent that the sequence of drug administration can significantly enhance the therapeutic effect of chemotherapy. These sequence-dependent effects can be explained by chemotherapy-induced cell cycle perturbations, or by pharmacodynamic interactions between the agents in combination. In this review, we focus on drug combinations with taxanes and camptothecins, which we believe best illustrate the importance of the cell cycle and pharmacologic interactions in the sequential administration of chemotherapy. As our understanding of the cell cycle grows, our ability to appropriately sequence chemotherapy can have a great impact on the treatment of human cancers. Copyright 2000 Harcourt Publishers Ltd.

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.

Phase II evaluation of 24-h continuous infusion topotecan in recurrent, potentially platinum-sensitive ovarian cancer: A Gynecologic Oncology Group study

OBJECTIVES

The aim of this study was to develop an alternative effective and more convenient administration schedule for intravenous topotecan when used as palliative treatment in ovarian cancer.

METHODS

The Gynecologic Oncology Group conducted a Phase II trial of 24-h infusional topotecan (8.5 mg/m(2)) with treatment repeated every 3 weeks in 29 patients with platinum-sensitive recurrent ovarian cancer (prior response to platinum-based chemotherapy with a minimum treatment-free interval >/=6 months).

RESULTS

The major toxicities of therapy were grade 4 neutropenia and thrombocytopenia which developed in 86 and 14% of patients, respectively. Other severe side effects were uncommon. Only 2 partial responses (7%) were observed in the 28 patients evaluable for response.

CONCLUSIONS

Despite the relatively favorable ovarian cancer patient population treated in this trial (platinum-sensitive recurrent disease), the response rate was disappointingly low. Considering the three- to fivefold higher objective response rates observed in other trials employing topotecan in individuals with platinum-sensitive ovarian cancer utilizing a 5-day treatment program (delivered every 3 weeks), the results of the current study provide strong support for the conclusion that clinically relevant antineoplastic activity of this agent is highly schedule dependent.

Lack of efficacy of 24-h infusional topotecan in platinum-refractory ovarian cancer: A Gynecologic Oncology Group trial

BACKGROUND

The aim of this study was to evaluate the efficacy of a more convenient topotecan administration schedule in the second-line treatment of advanced platinum-refractory ovarian cancer.

METHODS AND MATERIALS

The Gynecologic Oncology Group conducted a Phase II trial of 24-h infusional topotecan (8.5 mg/m(2)), repeated every 3 weeks in 26 patients with platinum-refractory ovarian cancer (failure to respond to initial platinum-based treatment or development of recurrent disease within 6 months of completion of chemotherapy).

RESULTS

Grade 4 neutropenia (85% of patients) and thrombocytopenia (12%) were the major toxicities encountered. Of the 25 patients evaluable for response, only a single patient experienced an objective response (4%).

CONCLUSIONS

When employed at this dose and schedule (24-h infusion every 3 weeks), topotecan has minimal second-line activity in platinum-refractory ovarian cancer.

Phase I and pharmacologic study of the combination of paclitaxel, cisplatin, and topotecan administered intravenously every 21 days as first-line therapy in patients with advanced ovarian cancer

PURPOSE

To evaluate the feasibility of administering topotecan in combination with paclitaxel and cisplatin without and with granulocyte colony-stimulating factor (G-CSF) support as first-line chemotherapy in women with incompletely resected stage III and stage IV ovarian carcinoma.

PATIENTS AND METHODS

Starting doses were paclitaxel 110 mg/m2 administered over 24 hours (day 1), followed by cisplatin 50 mg/m2 over 3 hours (day 2) and topotecan 0.3 mg/m2/d over 30 minutes for 5 consecutive days (days 2 to 6). Treatment was repeated every 3 weeks. After encountering dose-limiting toxicities (DLTs) without G-CSF support, the maximum-tolerated dose was defined as 5 microg/kg of G-CSF subcutaneously starting on day 6.

RESULTS

Twenty-one patients received a total of 116 courses at four different dose levels. The DLT was neutropenia. At the first dose level, all six patients experienced grade 4 myelosuppression. G-CSF support permitted further dose escalation of cisplatin and topotecan. Nonhematologic toxicities, primarily fatigue, nausea/vomiting, and neurosensory neuropathy, were observed but were generally mild. Of 15 patients assessable for response, nine had a complete response, four achieved a partial response, and two had stable disease.

CONCLUSION

Neutropenia was the DLT of this combination of paclitaxel, cisplatin, and topotecan. The recommended phase II dose is paclitaxel 110 mg/m2 (day 1), followed by cisplatin 75 mg/m2 (day 2) and topotecan 0.3 mg/m2/d (days 2 to 6) with G-CSF support repeated every 3 weeks.

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.

Phase I study of paclitaxel and etoposide for metastatic or recurrent malignancies

The authors define the dose-limiting toxicities and the recommended phase II doses of paclitaxel combined with etoposide, without and with filgrastim support. Patients with advanced solid tumors were eligible if they had a performance status of 0 to 2 and normal renal, hepatic, and bone marrow function. Patients with cardiac arrhythmias or congestive heart failure requiring medical therapy were excluded. Prior radiation was allowed only if it involved less than 30% of the marrow-containing skeleton. The dose of etoposide was fixed at 100 mg/m2/d for 3 days beginning on day 1. Paclitaxel was administered over 3 hours on day 4. The dose of paclitaxel was escalated until the maximum tolerated dose (MTD), without and with filgrastim 5 microg/kg (or 300 microg total dose) subcutaneously beginning on day 5, was reached. Treatment cycles were repeated every 21 days. Of 39 patients entered, 37 were evaluable for toxicity and 30 for response. The principal toxicity was neutropenia. Without filgrastim, the MTD of paclitaxel was 150 mg/m2. With filgrastim, the dose of paclitaxel was escalated to 250 mg/m2 in combination with etoposide 100 mg/m2. One episode of pulmonary toxicity was observed. Five patients responded: two with previously treated non-small-cell lung cancer (NSCLC), two with refractory small-cell lung cancer (SCLC), and one with refractory germ-cell tumor (GCT). We conclude that paclitaxel and etoposide can be given in combination at clinically relevant doses with filgrastim support. In this phase I trial, a dose of paclitaxel of 200 mg/m2 on day 4 and etoposide at 100 mg/m2/d on days 1-3, with filgrastim 5 microg/kg beginning on day 5, was found to be well tolerated, and can be recommended for future studies. Without filgrastim, a paclitaxel dose of 150 mg/m2 with the same dose of etoposide can also be recommended.

Clinical trials in patients with epithelial ovarian cancer: past, present and future

Combinations of surgery and chemotherapy are crucial in the treatment of ovarian cancer. This article reviews the conclusions of all recently performed trials and gives information on the now open randomized studies. The importance of radical surgery in combination with chemotherapy in early disease is clear, but uncertainties still exist in relation to timing and choice of chemotherapy. Many data from trials are helpful in outlining the indications for cytoreductive surgery, the timing of this procedure, second-look laparotomy in clinically complete remission, and secondary cytoreduction, but many details are yet to be addressed in future randomized studies. The place of new chemotherapeutic agents (in advanced disease and in adjuvant setting) is currently being investigated in many clinical trials.