Phase I study of daily times five topotecan and single injection of cisplatin in patients with previously untreated non-small-cell lung carcinoma

Role of Topotecan in Non-Small Cell Lung Cancer: A Review of Literature

Topotecan (TPT), a chemotherapeutic agent, is a topoisomerase-I inhibitor. Topoisomerase-I is a nuclear enzyme that relieves torsion strain in DNA by opening single strand breaks which helps in DNA replication. TPT inhibits this enzyme, thus preventing DNA replication and causes cell death. TPT has demonstrated to have broad spectrum of antitumor activity in tumors like cervical, ovarian, endometrial and small cell lung cancers (SCLCs). The intravenous (IV) formulation of the drug is currently approved by the US Food and Drug Administration for the treatment of patients with SCLC and ovarian cancer at a dose of 1.5 mg/m² administered daily for five consecutive days, with treatment cycles repeated every 3 weeks. TPT has shown some promising activity in the treatment of non-small cell lung cancer (NSCLC) with favorable side effect profile. Several clinical trials have been conducted with TPT in either IV or oral formulation for the treatment of NSCLC as a first or second-line treatment. Here we reviewed all the clinical trials done with TPT to date in the treatment of NSCLC both as a single-agent and combination therapy.

A phase I study of weekly topotecan in combination with pemetrexed in patients with advanced malignancies

INTRODUCTION

This phase I study evaluated the safety, tolerability, preliminary antitumor activity, and pharmacokinetic interaction of weekly topotecan (days 1 and 8) in combination with pemetrexed (day 1 only) in patients with advanced solid tumors.

METHODS

Patients received topotecan (3.0-4.0 mg/m(2) i.v. days 1 and 8) and pemetrexed (375-500 mg/m(2) i.v. day 1) over 21-day cycles. Patients were accrued across five different dose levels and were observed for safety, tolerability, and preliminary activity.

RESULTS

Twenty-six patients received 120 cycles of pemetrexed and topotecan, including five patients who received 8, 8, 10, 12, and 17 cycles without dose reductions, confirming a lack of cumulative myelosuppression. Four patients received topotecan (4.0 mg/m(2) i.v.) and pemetrexed (500 mg/m(2) i.v.), but experienced two dose-limiting toxicities (febrile neutropenia, grade 4 thrombocytopenia). As a result, the topotecan (3.5 mg/m(2) i.v.) and pemetrexed (500 mg/m(2) i.v.) group was expanded to 12 patients. The only grade 3 or 4 nonhematologic toxicity was one episode of grade 3 fatigue; no grade 3 or 4 nausea/vomiting/diarrhea, mucositis, or rash was reported. One non-small cell lung cancer (NSCLC) patient (12 months) and one soft tissue sarcoma patient (6 months) achieved a partial response.

CONCLUSIONS

Weekly topotecan plus every-3-week pemetrexed was well tolerated and active. Full doses of topotecan plus pemetrexed caused brief reversible myelosuppression with minimal dose delays/reductions; no grade 3 or 4 nausea/vomiting/diarrhea, mucositis, or rash was reported. All six NSCLC patients at the recommended phase II dose had at least stable disease as a best response, including one partial response lasting 12 months. There was no evidence of an effect of pemetrexed on topotecan pharmacokinetics. Collectively, these data suggest that further phase II exploration of weekly topotecan plus every-3-week pemetrexed for advanced malignancies is indicated.

Cancer therapies utilizing the camptothecins: a review of the in vivo literature

This review summarizes the in vivo assessment-preliminary, preclinical, and clinical-of chemotherapeutics derived from camptothecin or a derivative. Camptothecin is a naturally occurring, pentacyclic quinoline alkaloid that possesses high cytotoxic activity in a variety of cell lines. Major limitations of the drug, including poor solubility and hydrolysis under physiological conditions, prevent full clinical utilization. Camptothecin remains at equilibrium in an active lactone form and inactive hydrolyzed carboxylate form. The active lactone binds to DNA topoisomerase I cleavage complex, believed to be the single site of activity. Binding inhibits DNA religation, resulting in apoptosis. A series of small molecule camptothecin derivatives have been developed that increase solubility, lactone stability and bioavailability to varying levels of success. A number of macromolecular agents have also been described wherein camptothecin(s) are covalently appended or noncovalently associated with the goal of improving solubility and lactone stability, while taking advantage of the tumor physiology to deliver larger doses of drug to the tumor with lower systemic toxicity. With the increasing interest in drug delivery and polymer therapeutics, additional constructs are anticipated. The goal of this review is to summarize the relevant literature for others interested in the field of camptothecin-based therapeutics, specifically in the context of biodistribution, dosing regimens, and pharmacokinetics with the desire of providing a useful source of comparative data. To this end, only constructs where in vivo data is available are reported. The review includes published reports in English through mid-2009.

A phase I study of 3-day topotecan and cisplatin in elderly patients with small-cell lung cancer

PURPOSE

The aim of this phase I study was to determine the maximum-tolerated dose (MTD) in elderly patients with small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Patients aged over 75 years with previously untreated SCLC were enrolled in this study. Both topotecan and cisplatin were administered on days 1-3 and repeated every 3 weeks. The starting dose of topotecan was 0.5 mg/m2/day, while cisplatin was fixed at the dose of 20 mg/m2/day. Patients with limited disease (LD) SCLC received thoracic irradiation after the completion of chemotherapy.

RESULTS

Twenty-one elderly patients were enrolled in this study and received a total of 59 cycles. The major hematological toxicity was neutropenia and non-hematological toxicities including diarrhea were generally mild and reversible. The MTD of topotecan was determined as 1.2 mg/m2/day. The recommended phase II study dose of topotecan was determined as 1.0 mg/m2/day with cisplatin 20 mg/m2/day daily for 3 days. An objective response was observed in 6 of 10 patients (60%) with LD-SCLC and 6 of 11 (55%) with extensive disease (ED) SCLC. The median survival time in patients with LD-SCLC and those with ED-SCLC were 16.0 and 11.0 months, respectively.

CONCLUSION

The combination chemotherapy of 3-day topotecan and cisplatin appears to be tolerable and effective in elderly patients with SCLC.

Update on the role of topotecan in the treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is an aggressive disease that is generally resistant to chemotherapy. As a result, the prognosis for patients with NSCLC is poor. Currently, platinum-based regimens are the standard of care for patients with advanced NSCLC. However, these regimens are associated with severe and often cumulative hematologic and nonhematologic toxicities, limiting dose intensity. Therefore, novel chemotherapeutic agents and combination regimens may improve the outcome for these patients. A variety of new agents and combinations have been investigated in the treatment of NSCLC. However, to date, no clearly superior single-agent or combination regimen has emerged. Topotecan (Hycamtin; GlaxoSmithKline; Philadelphia, PA), a topoisomerase I inhibitor, is currently approved for the treatment of patients with relapsed small cell lung cancer (SCLC) and is associated with manageable, noncumulative, hematologic toxicities. In addition, topotecan demonstrates a favorable nonhematologic tolerability profile compared with agents currently used in the treatment of patients with NSCLC. The success of topotecan in patients with SCLC has made it an attractive option in the NSCLC setting. Topotecan-based combination regimens in the first-line treatment of NSCLC have demonstrated promising antitumor activities with favorable toxicity profiles. Many topotecan combination regimens have induced stable disease, a response that may offer meaningful clinical benefit in the palliative treatment of patients with advanced disease. Topotecan plus gemcitabine (Gemzar; Eli Lilly and Company; Indianapolis, IN) and single-agent topotecan may be particularly appropriate for patients in the second-line setting, in which palliation of symptoms is an important outcome of chemotherapy. Herein, the future role of topotecan in the first- and second-line treatment of NSCLC and the potential role of resistance mechanisms obtained from in vivo dose-response studies in designing future combination regimens are discussed.

A phase I study of OSI-211 and cisplatin as intravenous infusions given on days 1, 2 and 3 every 3 weeks in patients with solid cancers

BACKGROUND

OSI-211 (also known as NX211) is a liposomal preparation of the topoisomerase I inhibitor, lurtotecan, which has shown antitumor activity in phase I and II clinical trials. Cisplatin is a widely used antineoplastic agent with activity in a broad range of tumor types. This phase I trial was conducted to determine the recommended doses of these agents, and their pharmacokinetic properties and toxicities in patients with advanced solid malignancies.

PATIENTS AND METHODS

Fourteen patients with advanced and/or metastatic solid malignancies were enrolled in this trial. The first planned dose level was OSI-211 0.9 mg/m(2) with cisplatin 25 mg/m(2) administered intravenously daily for the first three consecutive days of a 21-day cycle. Patients were evaluated for hematological and non-hematological toxicities, and pharmacokinetic studies were performed on both agents.

RESULTS

The recommended phase II dose was determined to be 0.7 mg/m(2) OSI-211 given with 25 mg/m(2) cisplatin. Dose-limiting neutropenia was seen in two of three patients at the starting dose level. Three of 11 patients at the second (lower) dose level experienced dose-limiting thrombocytopenia; febrile neutropenia was also seen in one patient. Non-hematological toxicities were generally manageable and included fatigue, nausea and vomiting. Considerable variability was seen in both hematological toxicities and pharmacokinetics. One complete response and three partial responses were seen.

CONCLUSIONS

The recommended phase II dose for this combination is 0.7 mg/m(2) OSI-211 with 25 mg/m(2) cisplatin given as an intravenous infusion on days 1, 2 and 3 of a 21-day cycle. The main toxicity was myelosuppression. Preliminary evidence of antitumor activity was seen.

Radiation and third-generation chemotherapy

All of the third-generation chemotherapeutic agents reviewed in this article are independently active against NSCLC, although the agents differ significantly in their cellular and molecular mechanisms of cytotoxicity. All have also been shown to potentiate radiation effects, and thus are promising in exerting further cytotoxicity when used in combination chemoradiation therapy for locally advanced NSCLC. Although the toxicity to normal tissue varies among these agents when used alone, phase I/II clinical results consistently demonstrated higher risk and severity of esophagitis and pneumonitis when these agents were administered concurrently with thoracic radiation. These results were consistent with the radiosensitization properties of all these agents. Nonetheless, most chemoradiation combinations have been made feasible through careful phase I studies that establish safe doses of these agents given concurrently with radiation. Indeed, phase I outcomes consistently have demonstrated the need for dose reduction compared with doses applied in the stage IV, metastatic disease setting (see Tables 1 and 2). There have been many different dose schedules in phase I/II studies for stage III NSCLC, and most have yielded improved response rates with these agents. For all these agents discussed, multiagent chemoradiation increased toxicity when compared with single agent chemoradiation, particularly in the risk of neutropenia, and the tumor response rates were no better than single-agent chemoradiation. Most studies have not reached an adequate interval for survival endpoint to assess the impact on survival using multiagent chemoradiation. A few earlier studies using paclitaxel chemoradiation, in fact, showed that the significant improvement in tumor response rate resulted in only a small gain in survival outcome. Despite much preclinical research conducted with these agents, the optimal sequence and dose of drug and the optimal schedule for combining the two modalities remain unknown. Optimal sequencing of the chemoradiation regimens may improve distant disease control and primary tumor control, as was seen in studies that administered both full-dose induction chemotherapy and concurrent chemoradiation at reduced drug dose and in studies that administered consolidative, full-dose chemotherapy after chemoradiation. Strategically altering the treatment schedule may also enhance the radiosensitizing effects while keeping toxicity low, such as was seen in the pulsed low-dose paclitaxel chemoradiation reported by Chen et al . This pulsed low-dose schedule resulted in superior tumor response (100%) and durable primary tumor control while keeping the toxicity low. Other methods to minimize normal tissue injury and to deliver higher radiation doses, such as conformal three-dimensional radiotherapy that excludes nontarget tissues from the radiation field, are under investigation. Marks and colleagues were able to deliver radiation to 80 Gy using accelerated hyperfractionation radiation after induction chemotherapy. Intensity-modulated radiotherapy is expected to revolutionize the targeting of tumor and exclusion of normal tissues from the high-dose radiation volume in the future. Integrating biologic response modifiers, radioprotectors, and molecular targeting strategies also are being investigated. It remains unclear which agent among the third-generation drugs performs better for combination chemoradiation. The CALGB 9431 study reported by Vokes et al provided some preliminary information, in that it was a randomized phase II study of a three-arm comparison of cisplatin-containing, two-drug combination chemoradiation with one of the third-generation agents. Although direct statistical comparison between the treatment arms was not valid for a phase II setting, such an analysis did indeed reveal similar overall response rates for these three arms. Chemoradiation using third-generation chemotherapeutic agents has improved local tumor response rates, with enhanced radiation toxicity such as esophagitis and pneumonitis. The challenge of targeting distant disease control for locally advanced NSCLC continues.

Combination chemotherapy with topotecan for non-small cell lung cancer

Patients with non-small cell lung cancer (NSCLC) typically receive platinum-based combination chemotherapy. In spite of improvements in symptoms and survival, response rates remain low and newer agents are being investigated. The newer agents may offer increased efficacy and reduced toxicity compared with established agents and regimens. The topoisomerase-I inhibitor, topotecan, achieves single-agent response rates of 4-25% in NSCLC. Topotecan has also been studied in combinations: a combination of topotecan, administered using the standard 5-day schedule, with cisplatin was effective but was associated with myelosuppression. The combination of topotecan plus carboplatin may be better tolerated and warrants further investigation. Topotecan was also combined with newer agents (gemcitabine, vinorelbine, docetaxel, paclitaxel) using a range of different administration schedules of topotecan. Response rates of up to 30% were achieved. A weekly schedule of topotecan was effective and well tolerated and was also convenient for healthcare professionals and patients.

Ex vivo analysis of topotecan: advancing the application of laboratory-based clinical therapeutics

Topotecan is currently approved for relapsed small-cell lung cancer and ovarian cancer. Topotecan's efficacy in the second-line setting and novel mechanism of action suggest broad antitumour activity. We utilised a clinically validated, cell-death, ex vivo assay in human tumour explants to examine the activity profile of topotecan alone and in combination with other antitumour agents. Serial dilutions of topotecan alone and in combination with other cytotoxic agents were applied to biopsy specimens of non-small-cell lung cancer (NSCLC) and breast, colon, and prostate cancers. Dose-response curves were interpolated to provide 50% lethal concentrations (LC(50)). The degree of synergy (by median effect) and normalised Z-scores (raw scores converted to relative activity distributed around the mean) were then computed. Single-agent activity was observed for topotecan in all four tumour types. In 57 chemotherapy-naive specimens, NSCLC revealed the highest activity, demonstrated by the lowest LC(50) value (0.26+/-0.06 microg ml(-1); P=0.002). Overall, previously treated and chemotherapy-naive specimens revealed no significant differences in mean LC(50)'s. Synergy was observed for several combinations, including topotecan plus cisplatin in prostate and for topotecan plus 5-fluorouracil in breast cancers. The Z-score analyses conducted suggest activity for previously unexplored drug regimens, including topotecan plus 5-fluorouracil, vinorelbine, and mitomycin-C in NSCLC and breast cancer. Phase II studies are underway to determine the degree to which these ex vivo findings will translate into improved clinical results.

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.

Phase I study of sequential administration of topotecan and 5-fluorouracil in patients with advanced malignancies

Topotecan is a topoisomerase-I inhibitor, a drug that stabilizes a covalent complex of enzymes and causes strand cleavage of DNA. 5-Fluorouracil (5FU) is an antimetabolite that interferes with DNA synthesis. Preclinical studies using human cancer cell line models have shown potential therapeutic synergy between these two drugs by showing the maximum cytolytic effect using sequential 5FU followed by topotecan. In the current study, 5FU was used at a fixed dose of 375 mg/m2 given intravenously for five consecutive days on a 28 day cycle. Topotecan was dose-escalated in cohorts of patients from 0.5 to 1.0 mg/m2 given intravenously for 5 days after the 5FU dose. Eleven patients were entered at different dose levels. Both hematological and gastrointestinal toxicity were dose limiting. Diarrhea was the dose-limiting toxicity at the dose of 0.75 mg/m2 of topotecan. Two cases of grade 4 neutropenia were also observed at this dose level. One patient with small cell lung cancer had a complete response, while one patient with metastatic colorectal cancer had a partial remission. Three other patients had stable disease, lasting between 6 and 8 months. Overall, the regimen was well tolerated. A phase II study using a dose of 5FU at 375 mg/m2 followed by topotecan at 0.75 mg/m2 intravenously over 5 days every 28 days is recommended.

Topotecan preceded by oxaliplatin using a 3 week schedule: a phase I study in advanced cancer patients

Combinations of topoisomerase I (topo I) poisons and platinum derivatives have synergistic antitumoral effects. However, their clinical development is limited by supra-additive haematological toxicity. The aim of this study was to determine whether sustained doses of topotecan and oxaliplatin could be achieved using a synergistic sequence. 34 advanced cancer patients and 186 cycles were evaluable for toxicity over five dosing levels. Oxaliplatin at 85-110 mg/m(2) was given on day 1, followed by topotecan 0.5-1.25 mg/m(2)/day x 5 from day 1 to 5, every 3 weeks. Plasma pharmacokinetics (PK) of total and ultrafiltrable platinum, total and lactone forms of topotecan were determined in the first cycle. The dose-limiting toxicity (DT) was identified as grade 4 thrombocytopenia. The occurrence of grade 4 thrombocytopenia did not correlate with topotecan PK, but it did with the patient's characteristics. Severe thrombocytopenia was seen in 1/8 of patients without clinical or biological evidence of malnutrition, with a creatinine clearance higher than 1 ml/s, and no more than two previous chemotherapy regimens, while it was seen in 8/10 patients with one of these characteristics (P<0.004). In conclusion, the recommended doses of oxaliplatin 110 mg/m(2) and topotecan 1 mg/m(2)/day, every 3 weeks can be administered to patients with a favourable general status and pretreatment characteristics and a phase II study is worthwhile in ovarian cancer patients.

Phase II trial of topotecan and cisplatin in persistent or recurrent squamous and nonsquamous carcinomas of the cervix

OBJECTIVE

Cisplatin is a standard treatment in advanced, recurrent cervical cancer. Because topotecan is an established treatment in gynecologic malignancies such as ovarian cancer and exhibits nonoverlapping toxicity with cisplatin, a phase II trial was conducted to evaluate the tolerability and antitumor activity of a cisplatin/topotecan doublet in persistent or recurrent cervical cancer patients.

METHODS

Patients with bidimensionally measurable persistent or recurrent squamous cell and non squamous cell cervical cancer and adequate bone marrow were enrolled. Patients received 50 mg/m(2) of cisplatin intravenously over 1 h on Day 1 and 0.75 mg/m(2) of topotecan intravenously over 30 min on Days 1, 2, and 3 of 21-day cycles for six cycles or until disease progression. Tumor response and regimen toxicity were assessed using established Gynecologic Oncology Group criteria.

RESULTS

Thirty-two of 35 enrolled patients were evaluable for toxicity and tumor response. All but 2 evaluable patients had received previous radiotherapy. No patient received prior chemotherapy. The cisplatin/topotecan doublet was well tolerated, with 77 and 78% of courses given without interruption or delay and at full doses, respectively. As anticipated, the most common toxicity was hematologic, with grade 3/4 neutropenia and thrombocytopenia reported in 30 and 10% of cycles, respectively. The overall response rate was 28% (9/32), with 3 complete and 6 partial responses. The antitumor response in nonirradiated fields (30%) was similar to the response observed in previously irradiated fields (33%), suggesting good drug penetration. Median duration of response was 5 months (range, 2 to 15+ months). An additional 9 (28%) patients achieved stable disease. Median survival was 10 months, with 3 patients in lasting remission.

CONCLUSIONS

These results demonstrate that the cisplatin/topotecan combination is safe, well tolerated, and active in persistent or recurrent cervical cancer patients. A phase III, multicenter trial is under way (cisplatin/topotecan versus cisplatin) based on these favorable results to confirm the safety and efficacy profile in this patient population.

Topotecan in combination with carboplatin: phase I trial evaluation of two treatment schedules

BACKGROUND

Topotecan and cisplatin combinations have shown schedule-dependent toxicity, which may in part be due to cisplatin nephrotoxicity. As carboplatin is less nephrotoxic and increasingly replacing cisplatin in clinical practice, the aim of this study was to define the optimal sequence and dose for topotecan in combination with carboplatin.

PATIENTS AND METHODS

Two parallel phase I trials, with pharmacokinetic studies, were conducted administering carboplatin on day 1 with topotecan on days 1-5 (schedule A) or days 8-12 (schedule B). repeated every 3 weeks.

RESULTS

Twenty-one patients were treated over two dose levels, carboplatin AUC 4 [glomerular filtration rate (GFR) calculated from 51Cr-EDTA clearance] with topotecan 0.5 or 0.75 mg/m2. At the first dose level, six patients were evaluable for each schedule. With schedule A, from 34 cycles, there were two dose reductions and 10 treatment delays due to myelosuppression. With schedule B from 25 cycles, there was one reduction and 10 delays. At dose level 2, both patients in schedule A had dose-limiting neutropenia. In contrast, there was no dose-limiting toxicity with schedule B in six patients, although the majority of cycles were delayed.

CONCLUSION

The combination of topotecan and carboplatin using these 3-weekly schedules lead to significant myelotoxicity with attendant dose reductions and delays; the optimal scheduling of these agents remains to be defined.

Phase I study of combination topotecan and carboplatin in pediatric solid tumors

PURPOSE

We conducted a phase I trial of escalating doses of topotecan (TOPO) in association with a fixed systemic exposure of carboplatin (CARBO) with or without granulocyte colony-stimulating factor (G-CSF) in children.

PATIENTS AND METHODS

Two separate cohorts of patients (pts) with solid tumors were studied: (A) pts with refractory or recurrent disease and (B) pts with no prior myelosuppressive therapy or newly diagnosed tumors for which there was no standard chemotherapy. CARBO was given on day 1 at an area under the curve of 6.5, followed by TOPO as a continuous infusion for 3 days; the starting dose of TOPO was 0.50 mg/m(2)/d. Cycles were repeated every 21 days. G-CSF was given at a dose of 5 microg/kg/d starting on day 4.

RESULTS

Forty-eight of 51 pts were assessable for toxicity. In group A, dose-limiting myelosuppression persisted despite de-escalation of TOPO to 0.3 mg/m(2)/d and use of G-CSF. In group B, the maximum-tolerated dose of TOPO was 0.5 mg/m(2)/d for 3 days, and 0.6 mg/m(2)/d for 3 days with G-CSF. No significant nonhematologic toxicities were observed. Among 46 pts assessable for response, one had complete response, five had partial response, and 18 had stable disease.

CONCLUSION

Although this combination possesses antineoplastic activity in pediatric solid tumors, hematologic toxicity precluded any meaningful TOPO dose escalation. The addition of G-CSF did not alter this. The potential for preservation of activity and diminution of toxicity with alternative sequences and schedules of administration (topoisomerase followed by alkylating or platinating agents) should be evaluated.

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.

A phase I study of sequential intravenous topotecan and etoposide in lung cancer patients

PURPOSE

The topoisomerase I inhibitor topotecan (T) and the topoisomerase II inhibitor etoposide (E) are active drugs in lung cancer. The complementary functions of their targets may suggest benefit from the combined use of these agents but drug scheduling has been shown to play a critical role in preclinical models. To establish the optimal schedule and assess the impact of sequential administration of the combination of T and E, we conducted a dose finding study of sequential intravenous T and E in a four-weekly-schedule in relapsed lung cancer patients.

PATIENTS AND METHODS

The importance of drug sequence was assessed in consecutive patients throughout all dose levels; patients received in the first course either T followed by E (the TE group: T on days 1-3 and E on days 4-6) or E before T (the ET group: F on days 1-3 and Ton days 4-6). The sequence of Tand E was alternated in the successive courses. In this crossover design, each patient served as his own control for analysis of hematological toxicity in which TE sequence was compared to that of the ET sequence. Moreover, hematological toxicity after the first course was compared between the TE and the ET groups. The starting dose was T/E 0.75/75 mg/m2 at dose level 1and dose escalation was planned to T/E 1.00/75 mg/nm2 at dose level 2, T/E 1.00/100 mg/m2 at dose level 3, T/E 1.25/100 mg/m2 at dose level 4 and T/E 1.50/100 mg/m2 at dose level 5. Nineteen patients (small-cell lung cancer 7, non-small-cell lung cancer 11, mesothelioma 1 patient) were included.

RESULTS

The principal toxicity was myelosuppression, primarily neutropenia and thrombocytopenia. At dose level 3 several grade 4 toxicities were observed. DLT (febrile neutropenia) occurred in two patients, one in the TE and one in the ET group and precluded further dose escalation. There was no significant difference in WBC and platelet nadirs during the first course between the TE and the ET group. The influence of the sequence of administration of topotecan and etoposide was calculated by comparing the nadir values of cycles I and II for each patient. For none of the dose levels, a significant sequence-dependent effect could be detected. The MTD was reached at the doses of 100 mg/m2 topotecan and 75 mg/m2 etoposide. No objective responses were seen.

CONCLUSION

Although the combined use of topoisomerase I and II inhibitors is attractive on theoretical grounds, excessive myelosuppression prevents substantial dose escalation.

Repetitive high-dose topotecan, carboplatin, and paclitaxel with peripheral blood progenitor cell support in previously untreated ovarian cancer: results of a Phase I study

OBJECTIVE

In view of the significant activity of topotecan in ovarian cancer with dose-limiting toxicity (DLT) of myelosuppression, we evaluated the addition of topotecan to carboplatin and paclitaxel with peripheral blood progenitor cell (PBPC) support.

METHODS

Patients with previously untreated stage IIIC or IV ovarian cancer with macroscopic residual disease following primary debulking surgery were eligible. Patients received two cycles of carboplatin AUC = 5 and 175 mg/m(2) of paclitaxel with collection of PBPCs after the second cycle. Patients subsequently received three cycles of high-dose therapy (HDT) with topotecan on a daily x5 schedule, paclitaxel (250 mg/m(2) over 24 h), and carboplatin (AUC = 12-16).

RESULTS

Nineteen patients with a median age of 49 years (range 21-63) were enrolled and topotecan was escalated in 6 patient cohorts up to a dose of 4.5 mg/m(2)/day. Fifty-two of the planned 57 treatment cycles were delivered with no treatment-related deaths. Neutrophil and platelet recovery was rapid and the interval between HDT was 28 days. Febrile neutropenia occurred following 57% of all HDT cycles. DLTs of mucositis and diarrhea were observed at topotecan (4.5 mg/m(2)/day), paclitaxel (250 mg/m(2)) and carboplatin (AUC = 12). The protocol was subsequently modified to administer topotecan (2.5 mg/m(2)/day) with carboplatin (AUC = 16); however, 2 patients developed grade 4 diarrhea (1 with grade 3 mucositis and 1 with grade 4 mucositis). The clinical CR rate was 73% (14/19) with an overall clinical response rate of 95% (18/19). Of the 14 patients with a CCR, 13 of these underwent a second-look laparotomy with 8 (61%) achieving a pathological CR. With a median follow-up of 28 months (range 11-40 months), the median PFS is 36 months and OS has not been reached.

CONCLUSION

When combined with carboplatin (AUC = 12) and paclitaxel (250 mg/m(2)), the recommended topotecan dose is 3.5 mg/m(2)/day for 5 days. This outpatient HDT regimen combines three of the most active drugs in ovarian cancer with acceptable toxicity and promising activity.

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.

A dose escalating study of topotecan preceding cisplatin in previously untreated patients with small-cell lung cancer

BACKGROUND

The aim was to define the MTD of topotecan (TPT) given before cisplatin in patients with previously untreated SCLC.

PATIENTS AND METHODS

Alternating cycles A and B to a total of 6 cycles were given. Cycle A: TPT days 1-5 and cisplatin (50 mg/m2) day 5. Cycle B consisted of teniposide, carboplatin, vincristine, and cisplatin. TPT was escalated at doses 0.75, 1.0, 1.25, and 1.5 mg/m2. DLT was defined for the first cycle as grade 4 neutropenia with fever or when lasting > 7 days, or grade 4 thrombocytopenia.

RESULTS

Fifteen patients with limited disease and six patients with extensive disease were included. No episodes of DLT were recorded in the first cycles A and consequently 1.5 mg/m2 was defined as MTD. At 1.5 mg/m2 (11 patients, 30 cycles), four and three episodes of grade 4 thrombocytopenia and neutropenia lasting more than seven days occurred in subsequent cycles A. Thrombocytopenia and anaemia were cumulative as more cycles were administrated. Non-hematological toxicity was mild. The response rate was 86% (95% confidence interval (95% CI): 64%-97%) with 33% (95% CI: 15%-57%) achieving CR.

CONCLUSIONS

1.5 mg/m2 TPT can be delivered safely with 50 mg/m2 cisplatin on day 5 in patients with previously untreated SCLC.

Oral topoisomerase 1 inhibitors in adult patients: present and future

The renewed interest in topoisomerase 1 inhibitors, based on new insights on the mechanism of action and the development of semi-synthetic derivates of camptothecin with a more favourable toxicity profile, has led to extensive preclinical and clinical research. Significant levels of anti-tumor activity in human tumor xenografts were seen especially with prolonged duration of exposure. Since oral drug delivery is a more convenient method for prolonged drug administration, and preferred by patients, further development of oral formulations seems attractive. Common concerns in the development of oral formulations are their sometimes low oral bioavailability and the frequently large intra- and interpatient variation in systemic exposure. Efforts to improve absorption and minimize intestinal metabolism/efflux of the oral chemotherapeutic agent using new formulas might lead to better bioavailability. Pharmacokinetic and pharmacodynamic evaluations have enabled guidance in recommendations of schedules. Given the interpatient variation in exposure it is interesting to note that flat dosing of topotecan resulted in the same systemic exposure compared with the more complex dosing per body surface area. In order to diminish the interpatient variation in exposure to 9-AC a limited sampling model for oral 9-AC was developed, enabling prediction of the systemic exposure for 9-AC and optimizing treatment for any given patient. Drug sequencing plays a key role in the combination topotecan/cisplatin and might be important for combination with other classes of drugs. Therefore, forthcoming phase 1 trials on combination therapy with oral topoisomerase 1 inhibitors should include studies on sequence dependence and pharmacokinetic analyses to evaluate any mutual interaction.

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.