Activity and pharmacodynamics of 21-Day topotecan infusion in patients with ovarian cancer previously treated with platinum-based chemotherapy. New York Gynecologic Oncology Group

Naphthazarin suppresses cell proliferation and induces apoptosis in human colorectal cancer cells via the B-cell lymphoma 2/B-cell associated X protein signaling pathway

Colorectal cancer is the most common gastrointestinal cancer in the USA. Naphthazarin, one of the naturally available 1,4-naphthoquinone derivatives, is a natural bioactive molecule that exhibits an antitumor effect. To the best of our knowledge, this is the first study to investigate the anticancer effect of naphthazarin on cell proliferation and apoptosis in human SW480 colorectal cancer cells. In the present study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays were performed to assess the effect of napthazarin on cell proliferation and cytotoxicity of SW430 cells, respectively. In addition, an Annexin V-fluorescein isothiocyanate/propidium iodide apoptosis assay and 4',6-diamidino-2-phenylindole staining were used to analyze cell and nuclei apoptosis of SW480 cells, respectively, following treatment with naphthazarin. Poly (ADP-ribose) polymerase (PARP), B-cell lymphoma 2 (Bcl-2) and B-cell associated X protein (Bax) protein expression was analyzed by western blot. Furthermore, caspase-3 activation was analyzed using a commercial kit. The results revealed that naphthazarin exhibited cell growth inhibition, an increase in cytotoxicity and apoptosis induction in SW480 cells, which was associated with activation of the Bax/Bcl-2 signaling pathway and cleaved caspase-3 activation. However, no significant differences in PARP expression were identified following treatment with naphthazarin in SW480 cells. Taken together, these results suggest that naphthazarin decreased cell viability and induced apoptosis of SW480 cells, indicating that naphthazarin may present a potential therapeutic agent for human colorectal cancer treatment.

Macromolecular prodrug that provides the irinotecan (CPT-11) active-metabolite SN-38 with ultralong half-life, low C(max), and low glucuronide formation

We have recently reported a chemical approach for half-life extension that utilizes β-eliminative linkers to attach amine-containing drugs or prodrugs to macromolecules. The linkers release free drug or prodrug over periods ranging from a few hours to over 1 year. We adapted these linkers for use with phenol-containing drugs. Here, we prepared PEG conjugates of the irinotecan (CPT-11) active metabolite SN-38 via a phenyl ether that release the drug with predictable long half-lives. Pharmacokinetic studies in the rat indicate that, in contrast to other SN-38 prodrugs, the slowly released SN-38 shows a very low C(max), is kept above target concentrations for extended periods, and forms very little SN-38 glucuronide (the precursor of enterotoxic SN-38). The low SN-38 glucuronide is attributed to low hepatic uptake of SN-38. These macromolecular prodrugs have unique pharmacokinetic profiles that may translate to less intestinal toxicity and interpatient variability than the SN-38 prodrugs thus far studied.

A phase 2 study of oxaliplatin combined with continuous infusion topotecan for patients with previously treated ovarian cancer

BACKGROUND

Phase 2 trials suggest that prolonged intravenous (IV) infusion of the topoisomerase 1 inhibitor topotecan may be less toxic than when given by standard IV bolus 5-day administration. Oxaliplatin exhibits efficacy in platinum-pretreated disease and shows preclinical synergy with topoisomerase 1 inhibitors. We sought to determine the efficacy and safety of oxaliplatin plus infusion topotecan in recurrent platinum-pretreated ovarian cancer.

METHODS

Patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancers previously treated with 1 to 2 prior regimens including platinum and taxane received oxaliplatin (85 mg/m(2) day 1 and day 15) and topotecan (0.4 mg/m(2) per day) by continuous IV infusion over 14 days every 4 weeks. The primary objective of the trial was to estimate the objective response rate in platinum-resistant disease (stratum 1) and in platinum-sensitive disease (stratum 2). Toxicities were assessed in all patients.

RESULTS

Thirty-eight patients received 144 cycles of therapy (median, 4; range, 1-6). The most common grade 3 and grade 4 toxicities included thrombocytopenia (grade 3, 37%; and grade 4, 19%), neutropenia (grade 3, 37%; grade 4, 11%), and anemia (grade 3, 15%). Response occurred in 4 of 19 patients in stratum I (21%; 95% confidence intervals, 6%-46%) and 9 of 19 patients in stratum 2 (47%; 95% CI, 24%-71%). Three in each stratum had lengthy complete responses.

CONCLUSIONS

Biweekly oxaliplatin plus a 14-day continuous IV infusion of topotecan, given monthly, is an active regimen in platinum-pretreated ovarian cancer and merits additional evaluation.

First-in-human phase 1/2a trial of CRLX101, a cyclodextrin-containing polymer-camptothecin nanopharmaceutical in patients with advanced solid tumor malignancies

Patients with advanced solid malignancies were enrolled to an open-label, single-arm, dose-escalation study, in which CRLX101 was administered intravenously over 60 min among two dosing schedules, initially weekly at 6, 12, and 18 mg/m(2) and later bi-weekly at 12, 15, and 18 mg/m(2). The maximum tolerated dose (MTD) was determined at 15 mg/m(2) bi-weekly, and an expansion phase 2a study was completed. Patient samples were obtained for pharmacokinetic (PK) and pharmacodynamic (PD) assessments. Response was evaluated per RECIST criteria v1.0 every 8 weeks. Sixty-two patients (31 male; median age 63 years, range 39-79) received treatment. Bi-weekly dosing was generally well tolerated with myelosuppression being the dose-limiting toxicity. Among all phase 1/2a patients receiving the MTD (n = 44), most common grade 3/4 adverse events were neutropenia and fatigue. Evidence of systemic plasma exposure to both the polymer-conjugated and unconjugated CPT was observed in all treated patients. Mean elimination unconjugated CPT Tmax values ranged from 17.7 to 24.5 h, and maximum plasma concentrations and areas under the curve were generally proportional to dose for both polymer-conjugated and unconjugated CPT. Best overall response was stable disease in 28 patients (64 %) treated at the MTD and 16 (73 %) of a subset of NSCLC patients. Median progression-free survival (PFS) for patients treated at the MTD was 3.7 months and for the subset of NSCLC patients was 4.4 months. These combined phase 1/2a data demonstrate encouraging safety, pharmacokinetic, and efficacy results. Multinational phase 2 clinical development of CRLX101 across multiple tumor types is ongoing.

Topotecan plus carboplatin and paclitaxel in first-line treatment of advanced ovarian cancer: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate whether the addition of topotecan can improve the efficacy of carboplatin and paclitaxel in first-line treatment of advanced epithelial ovarian cancer.

METHODS

Meta-analysis was performed using a random effects model.

RESULTS

Four randomized controlled trials with a total of 3632 patients were identified and included in the meta-analysis. No significant differences were observed in terms of progression-free survival (P=0.400), overall survival (P=0.502) and overall response rate (P=0.953) between patients treated with topotecan plus carboplatin and paclitaxel versus carboplatin and paclitaxel. However, there were significantly higher rates of grade 3-4 leucopenia (P=0.024), neutropenia (P<0.001), anaemia (P<0.001), and thrombopenia (P<0.001) in the topotecan plus carboplatin and paclitaxel group. No significant differences were observed in grade 3-4 nausea (P=0.352) and vomiting (P=0.092) between these two groups.

CONCLUSION

Topotecan plus carboplatin and paclitaxel did not improve survival outcomes and caused more haematological toxicity for advanced ovarian cancer.

Activity of topotecan 21-day infusion in patients with previously treated large cell lymphoma: long-term follow-up of an Eastern Cooperative Oncology Group study (E5493)

The purpose of this study was to determine the activity of topotecan given by 21-day continuous infusion in patients previously treated with one prior therapy for a diffuse large-cell lymphoma or immunoblastic lymphoma. Patients with appropriate histology and measurable disease who had been treated with one prior chemotherapy regimen were eligible for study. Slides of tumor biopsies were submitted for central review of pathology. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2 and adequate bone marrow function. Patients were treated with continuous infusion topotecan, 0.4 mg/m(2)/day × 21 days. Therapy could be escalated to 0.5 and then 0.6 mg/m(2)/day in subsequent cycles if there was no dose-limiting toxicity at the initial dose level. Patients were treated with two cycles after achieving a complete response or until disease progression or unacceptable toxicity occurred. Thirty-seven patients were enrolled. However, only 26 cases were eligible due to a performance status of > 2 (n = 2), more than one prior chemotherapy (n = 1) and wrong histology on review (n = 8). Due to the unexpectedly high ineligibility rate, two sets of analysis were done for all 37 patients enrolled and for the 26 eligible patients, respectively. Of the 37 patients (15 males and 22 females), the International Prognostic Index included 11% low risk, 30% low intermediate risk, 46% high intermediate risk and 8% high risk. The median follow-up was 77 months. A total of 136 cycles of therapy were given with a median of 3 cycles per patient. Grade 4 toxicities included: 14% grade 4 thrombocytopenia; 14% grade 4 granulocytopenia, 8% leukopenia, 3% each anemia, hemorrhage, infection, vomiting, thrombosis, liver toxicity and neuromotor toxicity. The response analysis including all 37 patients showed five complete responses (CRs) and four partial responses (PRs) for a total response rate of 24% (90% two-stage confidence interval 13-39%). Median progression-free survival (PFS) was 3.7 months, with 1- and 2-year PFS of 21% and 6%, respectively (90% confidence interval 11-34% and 2-15%). Median overall survival (OS) was 10.5 months, with 1- and 2-year OS of 41% and 27%, respectively (90% confidence interval 27-53% and 16-39%). Analysis including only eligible patients showed similar response rates and survival outcomes. Single agent topotecan has moderate activity for previously treated high-grade lymphoma equivalent to that of several newer agents, and should be considered for incorporation into multi-drug salvage chemotherapy programs.

A phase I study to characterize the safety, tolerability, and pharmacokinetics of topotecan at 4 mg/m2 administered weekly as a 30-minute intravenous infusion in patients with cancer

Topotecan pharmacokinetics at higher infusion rates (4 mg/m2 over 30 minutes) have not been studied. The authors report a pharmacokinetics and safety study of this dose in advanced cancer patients. Sixteen patients were given a 4-mg/m2 topotecan infusion intravenously (IV) over 30 minutes weekly for 3 weeks, repeated every 28 days. Pharmacokinetics were determined after the first dose. Plasma concentrations of total topotecan were measured to derive CL, V(ss), C(max), t(max), t(1/2), AUC(0-t), and AUC(0-infinity). Plasma total topotecan concentrations decreased biexponentially, with a mean CL value of 20.6 L/h, V(ss) value of 101 L, and t(1/2) value of 5.0 h. Nine significant adverse events (all hematologic) were topotecan related. Grade 3 or less adverse events included anemia, thrombocytopenia, leukopenia, and fatigue. Pharmacokinetics of the 4-mg/m2 infusion of topotecan over 30 minutes are comparable to findings from studies of lower and higher doses. Toxicities are similar to previous reports.

Management of recurrent ovarian carcinoma: current status and future directions

The majority of patients who present with epithelial ovarian cancer respond well to the initial treatment, but will ultimately experience a recurrence of their disease. Chemotherapy can palliate symptoms of disease recurrence, and there is some evidence that it also can improve survival. Recurrent ovarian carcinoma is divided into two subsets of patients: those with platinum-sensitive disease and those with platinum-resistant disease. Management for these two groups has diverged in the last few years, as evidence accrues that the response to treatment and duration of treatment-free interval after completion of front-line therapy impacts the prognosis and the treatment choice for these patients. Recent randomized trials have demonstrated a benefit for platinum combination re-treatment in patients with platinum-sensitive disease. Additionally, there are multiple single-agent trials evaluating novel agents for patients with platinum-resistant as well as platinum-sensitive disease. This review will discuss the role of chemotherapy in recurrent disease, describe the various agents used in this setting, and touch on the role of biologic agents in recurrent epithelial ovarian carcinoma.

Management of platinum-resistant ovarian cancer with the combination of pemetrexed and gemcitabine

INTRODUCTION

Platinum resistant ovarian cancer is a current challenge in Oncology. Current approved therapies offer no more of a 20% of response. New therapeutic options are urgently needed.

PATIENTS AND METHODS

Patients were treated with the combination of Pemetrexed 500 mg/m(2) d1 and Gemcitabine 1000 mg/m(2) d1,8 in a 21 days basis.

RESULTS

10 platinum-resistant ovarian cancer patients were treated under compassionate use. Mean previous chemotherapy lines were 3.3. Mean administered cycles were 4. Mean CA 125 decrease was on average of 47%, with one patient experiencing a 95% decrease in her CA 125 level. 1 patient had a complete clinical remission, and 2, had partial radiological responses. Mean Progression free survival was 16.5 weeks, and Overall Survival was 21.2 weeks. Treatment was well tolerated.

CONCLUSIONS

Deemd to the observed activity, the combination of Pemetrexed and Gemcitabine deserves deeper investigation in platinum-resistant ovarian cancer patients.

Topotecan for ovarian cancer

BACKGROUND

Chemotherapeutic agents such as topotecan can be used to treat ovarian cancer. The effects of using topotecan as a therapeutic agent have not been previously been systematically reviewed.

OBJECTIVES

To systematically evaluate the effectiveness and safety of topotecan for the treatment of ovarian cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), (Issue 4, 2006); Cochrane Gynaecological Cancer Review Group (CGCRG) Specialised Register (Cochrane Library Issue 4, 2006); MEDLINE (January 1990 to 27 July 2006); EMBASE (January 1990 to 27 July 2006); The European Organization for the Research and Treatment of Cancer (EORTC) database (to 1 August 2006); CBM (Chinese Biomedical Database) (January 1990 to 27 July 2006).

SELECTION CRITERIA

Randomised controlled trials (RCTs) which randomized patients with ovarian cancer to single or combined use of topotecan versus interventions without topotecan, or different remedies of topotecan.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data.

MAIN RESULTS

Six studies including 1323 participants were eligible for this review (Gordon 2004a; Gore 2001a; Gore 2002; Hoskins 1998; Huinink 2004; Placido 2004) All studies, as reported, were identified as being of poor methodological quality. Topotecan had comparable effectiveness to prolong progression-free survival (PFS) compared with pegylated liposomal doxorubicin (PLD), (16.1 weeks versus 17.0 weeks; p = 0.095). Overall survival (OS) time was similar in participants using PLD compared with topotecan (56.7 weeks versus 60 weeks; p = 0.341). Topotecan was more hematologically toxic compared with paclitaxel or PLD, relative risks (RRs) of hematological events: ranged from 1.03 to 14.46 and 1.73 to 27.12 respectively. A 21-day cycle of topotecan was more toxic than a 42-day cycle (RRs of hematological and non-hematological events ranged from 1.03 to 8). Intravenous and oral topotecan had comparable toxicity. Topotecan delayed progression more effectively compared with paclitaxel (23.1 weeks versus 14 weeks, p = 0.0021). Participants were more likely to respond to topotecan on a 21-day cycle as opposed to a 42-day cycle (RR 7.23, 95% CI 0.94 to 55.36). Small tumor diameter, sensitivity to platinum-based chemotherapy was associated with better prognosis. Small sample size, methodological flaws and poor reporting of the included trials made measurement bias of the trials difficult to assess.

AUTHORS' CONCLUSIONS

Topotecan appears to have a similar level of effectiveness as paclitaxel and PLD, though with different patterns of side effects. Larger, well-designed RCTs are required in order to define an optimal regime.

Tolerance and activity of oxaliplatin with protracted topotecan infusion in patients with previously treated ovarian cancer. A phase I study

BACKGROUND

Topotecan 14-day infusion combined with cisplatin was highly active in ovarian cancer, but too myelosuppressive. We therefore sought to evaluate the feasibility of substituting oxaliplatin for cisplatin to improve safety.

METHODS

Ovarian and primary peritoneal cancer patients, pretreated with at least one prior platinum-containing regimen, performance status (PS) 0-1, without prior pelvic radiation were eligible. Topotecan was continuously infused days 1-15; oxaliplatin was given days 1 and 15; cycles were repeated every 28 days. Five dose levels were explored: topotecan (mg/m2/day)/oxaliplatin (mg/m2) doses: (1) 0.2/65; (2) 0.2/75; (3) 0.2/85; (4) 0.3/85; (5) 0.4/85.

RESULTS

Twenty-three patients (20 ovarian, 1 tubal, and 2 peritoneal) were entered: median age 56 years (range, 37-77); PS: 0=12 and 1=11; histology: papillary serous 7, serous 4, adenocarcinoma 8, poorly differentiated 2. Median of 4 cycles were delivered. Grade 3 neutropenia occurred in 3 of 7 patients at level 5 (with fever at levels 4 and 5), without grade 4 neutropenia or thrombocytopenia. Other toxicities were mild and reversible (mainly gastrointestinal), except one grade 3 neuropathy and one oxaliplatin-related grade 3 hypersensitivity reaction. Six objective responses (five of them complete) were documented among 22 patients spanning several dose levels.

CONCLUSION

Topotecan continuous infusion, combined with oxaliplatin, was associated with no grade 4 hematologic toxicity and evidence of activity. The recommended phase II dose is topotecan 0.4 mg/m2/day continuous infusion d1-15 with oxaliplatin 85 mg/m2 on days 1 and 15. A phase II evaluation as second-line treatment for both platinum-sensitive and -resistant ovarian cancer recurrences is ongoing.

A phase I, randomized, open-label, parallel-cohort, dose-finding study of elacridar (GF120918) and oral topotecan in cancer patients

PURPOSE

Breast cancer resistance protein (ABCG2) substantially limits the oral bioavailability of topotecan. Coadministration with elacridar, an inhibitor of breast cancer resistance protein-mediated drug transport, increases the bioavailability of topotecan. The aim of this study was to establish the lowest effective dose of elacridar to obtain maximum oral bioavailability of topotecan and to determine the optimal schedule of coadministration of oral topotecan and elacridar. In the second part of this study, dose-limiting toxicities and maximum tolerated dose of oral topotecan coadministered with elacridar, at a daily times five regimen administered every 21 days, were established.

EXPERIMENTAL DESIGN

In part I, 20 patients were randomized to receive 100, 300, 500, 700, or 1,000 mg of elacridar on days 1 and 8 1 h before or simultaneously with 2.0 mg oral topotecan, which was also randomized. On day 15, all patients were treated with 1.5 mg/m(2) i.v. topotecan. In part II of the study, patients were treated daily with oral topotecan and with the lowest effective dose of elacridar following from part I. The maximum tolerated dose and dose-limiting toxicity were determined in cohorts of three patients. Blood samples were taken on days 1, 8, and 15 of part I and on day 1 of cycles 1 and 2 of part II.

RESULTS

Complete apparent oral bioavailability of topotecan (102 +/- 7%) for all treatment arms with elacridar in both schedules was seen in part I. In the topotecan dose escalation part, two dose-limiting toxicities were seen at the 2.5 mg topotecan dose level.

CONCLUSION

The recommended schedule is 2.0 mg oral topotecan plus 100 mg elacridar administered concomitantly daily times five every 21 days.

Phase I/II study of IV topotecan in combination with whole brain radiation for the treatment of brain metastases

A phase I/II trial was conducted to determine the toxicities and efficacy (overall response, overall survival, and progression-free survival) of the combination of topotecan and whole brain radiation therapy (XRT) in patients with brain metastases. Patients received 30 Gy XRT given in 10 fractions to the whole brain. In phase I, patients were treated in groups of three at each topotecan dose level; dose escalation proceeded until the maximum tolerated dose (MTD) was identified. The dose-limiting toxicity proved to be grade IV neutropenia at 0.6 mg/m2/d, resulting in an MTD of 0.5 mg/m2/d. One of nine patients showed a response to treatment, and that was partial (OR 11%). Three had stable disease (33%), and four experienced progressive disease (44%). Median progression-free survival was 60 d; median overall survival was 102 d. Intravenous topotecan at 0.5 mg/m2/d concomitant to XRT with 30 Gy in 3-Gy fractions is tolerable in patients with brain metastases. This regimen has the additional advantage of providing systemic treatment to patients with metastases in other locations while whole brain radiation is in progress. Although response and survival outcomes in this small study do not appear higher than expected from historical controls, these were not primary end points, and larger studies on this topic would be useful to elucidate the efficacy of this combination treatment regimen.

Use of systemic therapy in women with recurrent ovarian cancer--development of a national clinical practice guideline

OBJECTIVE

To develop a guidance document concerning the use of systemic therapy for women with recurrent ovarian cancer that would be applicable for the Canadian health care system. This will be done using a standardized systematic review process, guideline evaluation instruments, multi-disciplinary expert consensus opinion and evidence-rating systems.

DATA SELECTION

The primary data sources were MEDLINE, National Guideline Clearinghouse and Cochrane Library.

METHODS

Clinical practice guidelines, technology assessments, systematic reviews and randomized controlled trials addressing systemic therapy for women with recurrent ovarian cancer were eligible.

DATA EXTRACTION

Data was identified and extracted by the methodology team and reviewed by the authors. Results were reviewed and discussed by members of an expert working group comprised of a multidisciplinary and geographic divergent group of practitioners.

DATA SYNTHESIS

The existing 7 practice guidelines underwent formal evaluation for quality, currency and content using the AGREE tool. Recommendations with evidence-ratings were developed. This data was used by a pan-Canadian panel in an informal consensus process, which resulted in the initial draft of a guideline. The guideline team reviewed the draft and made further edits to ensure the guideline's appropriateness for a national context. Practitioner feedback was requested from 165 health care providers who treat ovarian cancer from across Canada. Overall response rate was 37% and was very positive. Comments were reviewed and the guideline was edited appropriately.

CONCLUSION

The development of a national practice guideline on the use of systemic therapy for recurrent ovarian cancer was feasible using systematic literature review, expert consensus, guideline evaluation instruments, evidence-rating systems, independent internal and external review measures and final approval by a national discipline specific society (GOC). Recommendations for practice are offered.

Safety of topotecan in the treatment of recurrent small-cell lung cancer and ovarian cancer

The topoisomerase I inhibitor, topotecan, is approved for the treatment of recurrent small-cell lung cancer (SCLC) and ovarian cancer (OC). Patients with recurrent SCLC and OC typically experience multiple relapses and receive multiple rounds of chemotherapy. In these settings, disease stabilisation is considered a treatment benefit, and quality-of-life effects and cumulative toxicities of treatments should be considered. Many patients with recurrent cancer may be predisposed to treatment-related adverse events because of advanced age, renal impairment or extensive prior therapy. The standard regimen of topotecan, 1.5 mg/m(2) on days 1-5 of a 21-day cycle, has generally mild nonhaematological toxicity and a well-defined haematological toxicity profile characterised by reversible and noncumulative neutropenia. Alternative regimens may lower the incidence of haematological toxicities and maintain antitumour efficacy. Topotecan may provide physicians with a versatile therapeutic option for the treatment of patients with relapsed SCLC or OC.

A phase I trial of oxaliplatin and topotecan in recurrent ovarian carcinoma

OBJECTIVE

Oxaliplatin and topotecan have demonstrated activity as single agents against recurrent platinum-sensitive and -resistant ovarian cancer, as well as synergy in vitro. This was a dose-finding study of combination therapy with weekly topotecan and alternating-week oxaliplatin in patients with recurrent epithelial ovarian cancer.

METHODS

Eligible patients had a diagnosis of recurrent ovarian or primary peritoneal carcinoma, a performance status of 0-2, and normal bone marrow, renal, and hepatic function. On days 1 and 15 of a 28-day cycle, patients received a fixed dose of oxaliplatin (85 mg/m2) via intravenous infusion. On days 1, 8, and 15, patients received an escalating dose of intravenous topotecan (2.0-4.0 mg/m2). Five dose levels were planned with a minimum cohort of 3 patients at each level.

RESULTS

Thirteen patients were enrolled and received a total of 50 cycles of chemotherapy. The maximum tolerated dose was 85 mg/m2 of oxaliplatin and 3.0 mg/m2 of topotecan, and grade 3 neutropenia was the dose-limiting toxicity. Four of nine (44%) evaluable patients had stable disease or a partial response to the drug combination as assessed by cancer antigen-125 levels.

CONCLUSIONS

A 28-day schedule of oxaliplatin and topotecan is safe and well tolerated. Because of the in vitro synergy observed between topoisomerase I inhibitors and platinum derivatives and the tolerability reported in the current study, this regimen warrants further investigation.

Randomised phase II study comparing topotecan/carboplatin administration for 5 versus 3 days in the treatment of extensive-stage small-cell lung cancer

BACKGROUND

Topotecan is an active drug in small-cell lung cancer (SCLC). In our previous study, a combination of topotecan with cisplatin was associated with a median overall survival of 7.6 or 8.7 months, depending on the duration of treatment. We have replaced cisplatin by carboplatin in this trial, with the objective of creating a more convenient schedule for our patients. Furthermore, we have also compared the standard 5-day schedule with an experimental 3-day schedule.

PATIENTS AND METHODS

A total of 100 patients with metastatic disease were included. Patients were randomly assigned to receive either topotecan 0.75 mg/m2, days 1-5, and carboplatin AUC 5, day 5 (arm A) or topotecan 1.25 mg/m2, days 1-3, and carboplatin AUC 5, day 3 (arm B). Six cycles were given at a 3-week interval.

RESULTS

A total of 91 patients were assessable for response. The response during therapy was 86.9% in arm A and 80.0% in arm B. Median survival in arm A was 11.8 months and in arm B 11.6 months (P=0.37).

CONCLUSIONS

The combination of topotecan and carboplatin is active in extensive-disease SCLC. Toxicity and median survival were comparable in both arms. Three days of treatment seems to be similar to the 5-day regimen.

Proceedings of a GOG workshop on intraperitoneal therapy for ovarian cancer

Ovarian cancer is the leading cause of gynecologic cancer deaths in the U.S. The concept of intraperitoneal drug delivery for therapy of intraperitoneal cancers, such as ovarian cancer, arose in the 1960s. The field of intraperitoneal cisplatin therapy for ovarian cancer was initiated in the late 1970s and early 1980s. The markedly improved survival data resulting from a phase III trial of intraperitoneal cisplatin for ovarian cancer in early 2006 led to an NCI Clinical Announcement and a Gynecologic Oncology Group-sponsored workshop on intraperitoneal therapy in January, 2006, in San Diego, California. The proceedings of this workshop summarize both research trial results and practical implementation issues associated with intraperitoneal therapy discussed at this workshop.

Topotecan by 21-day continuous infusion in children with relapsed or refractory solid tumors: a Children's Oncology Group study

PURPOSE

The Children's Oncology Group conducted a phase II trial of 21-day continuous infusion topotecan to determine the response rate in pediatric patients with recurrent or refractory malignant solid tumors.

PROCEDURE

Patients with Ewing sarcoma family of tumors (ESFT), osteosarcoma (OS), soft tissue sarcomas (STS), medulloblastoma (MB)/primitive neuroectodermal tumor (PNET), astrocytoma, or neuroblastoma (NB) recurrent or refractory to conventional therapy, measurable disease, and adequate organ function were treated with topotecan 0.3 mg/m2/day by continuous intravenous infusion for 21 consecutive days, followed by 7 days without therapy prior to response assessment.

RESULTS

Fifty-five patients were enrolled; two were ineligible, two were removed from protocol therapy prior to evaluation for response, and one was inevaluable for response, leaving 53 and 50 patients evaluable for toxicity and response, respectively. Objective responses were seen in 2/20 patients with ESFT (both partial responses, 4 and 19 courses), 0/10 OS patients, and 0/12 STS patients. There were insufficient patients enrolled to determine the response rate for the MB/PNET, astrocytoma, and NB strata. The most common Grade 3 or 4 toxicities during the first course of therapy were thrombocytopenia (12/53), neutropenia (8/53), and fatigue (7/53).

CONCLUSION

Intravenous topotecan by 21-day continuous infusion is tolerable in pediatric patients with recurrent or refractory solid tumors. Limited activity was seen in ESFT and further development of this topotecan schedule as a single agent is not warranted.

Ethnicity is a factor to be considered before dose planning in ovarian cancer patients to be treated with topotecan

The objective of this study was to determine the efficacy and toxicity of topotecan in Chinese patients with ovarian cancer. A retrospective analysis on recurrent ovarian cancer patients receiving topotecan 1.25 mg/m(2) daily for 5 consecutive days on a 21-day cycle from 1997 to 2002 was conducted. The patients included were all treated with at least two cycles of topotecan. The patient characteristics were compared in relation to their toxicity profile and their response to treatment. Response was evaluated by physical findings, imaging techniques, and serum CA125 level. A total of 60 patients were included in the study. All patients were evaluable for response and toxicities. A total of 361 cycles were given (median, 5 per patient; range 2-15). The major toxicity was neutropenia, which was grade 4 in 45.0% of the patients and 10.2% of the cycles. Age was the only covariate predicting the occurrence of grade 4 neutropenia (logistic regression P= 0.046, CI 1.01-1.12). Neutropenic fever occurred in 8.3% of the patients. Eighteen (30%) patients were required to delay their chemotherapy and 11 (18.3%) required dose reduction. Nonhematologic toxicities were mild. The overall response rate was 21.6%, with eight (13.3%) complete responses and five (8.3%) partial responses. The median duration of response and median time to progression were 11 and 5 months, respectively. The median survival was 14 months. Topotecan 1.25 mg/m(2) in a five-times-daily schedule was well tolerated in a cohort of Chinese patients. Myelotoxicity was the most important side effect in our study, but the incidence is much lower than that reported in other studies. Age was an independent factor predicting the occurrence of grade 4 neutropenia.

Sequence dependence of hematologic toxicity using carboplatin and topotecan for primary therapy of advanced epithelial ovarian cancer: a phase I study of the Gynecologic Oncology Group

PURPOSE

Selection of a feasible sequence and schedule of carboplatin in combination with topotecan for evaluation in advanced epithelial ovarian cancer (EOC).

PATIENTS AND METHODS

Women with stages III-IV EOC or primary peritoneal carcinoma without prior chemotherapy were assigned to consecutive cohorts evaluating a "forward" (carboplatin day 1, topotecan days 1-3), "reverse" (carboplatin day 3, topotecan days 1-3), or "extended reverse" sequence (carboplatin day 5, topotecan days 1-5). Patients received 4 cycles carboplatin-topotecan followed by 4 cycles carboplatin-paclitaxel. Feasibility was defined according to the cumulative proportion of patients with dose-limiting events (DLEs) during the first four cycles.

RESULTS

Sixty-eight patients were enrolled across 5 cohorts. The forward sequence demonstrated unacceptable hematologic DLEs at the lowest topotecan dose (0.75 mg/m2/day x 3 days). The reverse sequence was feasible at 1.25 mg/m2/day x 3 days, with only 1/15 patients experiencing a DLE within 4 cycles, and 14/15 patients were able to receive 4 subsequent cycles of carboplatin-paclitaxel. The extended reverse sequence was associated with excessive DLEs at 1.00 mg/m2/day x 5 days. Prophylactic hematopoietic growth factors were not required.

CONCLUSION

Higher doses of topotecan could be safely administered with reduced toxicity over multiple cycles using the reverse sequence, which was selected for phase III evaluation. The relative efficacy of the forward and reverse sequence is unknown.

Prolonged topotecan infusion with cisplatin in the first-line treatment of ovarian cancer: An NYGOG and ECOG study

OBJECTIVE

To determine the toxicity and efficacy of combined therapy with cisplatin and prolonged infusion topotecan as front line therapy in women with epithelial ovarian cancer.

PATIENTS AND METHODS

Women with previously untreated, measurable and non-measurable epithelial ovarian cancer, stages Ic-IV were eligible. Patients were treated with cisplatin 75 mg/m(2) on day 1, followed by topotecan 0.3 to 0.4 mg/m(2)/day given as a continuous infusion over 14-21 days, every 28 days. Dose levels and duration of infusion were adjusted for toxicity as appropriate. Patients were evaluated for response to treatment and treatment toxicity by standard NYGOG criteria.

RESULTS

Sixty patients were enrolled. Among the 20 patients with post-surgical residual disease >2 cm, 80% [95% CI (56.3%, 94.3%)] demonstrated an objective response to therapy. The median progression-free survival for all 60 patients enrolled was 19.3 months with a median overall survival of 45.6 months given the median follow-up of 55 months (range 6-81 months). Five year survival is estimated to be 41%. Toxicity was observed in the first four patients treated with topotecan (0.4 mg/m(2)/day x 21 days) and dosing was continued at 0.3 mg/m(2)/day x 14 days thereafter. Of the 56 patients treated at the amended dose level, marrow suppression continued to be dose-limiting, with 86% of patients experiencing grade 3 or 4 neutropenia, 55% experiencing grade 3 or 4 thrombocytopenia and 50% of patients experiencing grade 3 or 4 anemia. Nonetheless, only 11/245 cycles administered were associated with febrile neutropenia and/or infection (8 port-related). Other non-hematologic toxicity was as expected. There were no treatment-related deaths.

CONCLUSION

This large, multicenter phase II study of prolonged infusion topotecan in combination with cisplatin demonstrated similar response, time to progression and survival compared with reported results of taxane and platinum combinations. Hematologic toxicity was greater but tolerated. Further studies investigating topotecan in combination with platinum therapy as a first line agent are warranted.

Sequential prolonged oral topotecan and prolonged oral etoposide as second-line therapy in ovarian or peritoneal carcinoma: a phase I Gynecologic Oncology Group study

OBJECTIVE

Preclinical models suggest synergy when topoisomerase I and II inhibitors are given sequentially, but not simultaneously. A phase I study was conducted in previously treated ovarian or peritoneal carcinoma to determine the tolerability (maximum number of days) of sequential oral topotecan and oral etoposide.

METHODS

Topotecan (0.8 mg/m(2)) was administered daily (days 1-5) followed by etoposide (50 mg/m(2)) administered daily for up to 5 days (days 8-12). Patients on dose levels 3 and 4 repeated topotecan for up to 5 days starting on day 15 after the initial topotecan and etoposide sequence. Cycles were repeated every 28 days. Dose-limiting toxicities (DLT) were defined as: neutrophils <1000/microl or platelets <50,000/microl before completing administration of etoposide or topotecan; neutropenic fever; platelets <20,000/microl; or a delay greater than 2 weeks in starting cycle 2 due to hematologic toxicity (ANC <1500/microl or platelets <100,000/microl on scheduled day of treatment).

RESULTS

Nineteen patients were entered into this trial, and a total of 54 cycles (range 1-10) of therapy were administered. Dose-limiting toxicities, principally neutropenia, occurred when therapy was administered for 3 of 4 weeks.

CONCLUSION

Oral topotecan and oral etoposide administered at these doses daily for 5 days sequentially for a maximum of three (out of every four) weeks of therapy are tolerable. In some cases, it may be necessary to hold therapy the third week. Based on the activity seen in this patient population, it is planned to take this regimen into a phase II setting.

Phase-I study of a new schedule based on increasing days of topotecan administration associated with dose individualisation

BACKGROUND

The most commonly prescribed schedule of topotecan administration is daily for five days, every 21 days. Both pre-clinical and clinical studies suggest that a more protracted schedule may increase its therapeutic index. The current study was undertaken to determine the maximum tolerated number of days with 30-minute i.v. infusion of topotecan daily at fixed area under the plasma concentration-time curve (AUC) (i.e., 35 microg/Lxh).

PATIENTS AND METHODS

Topotecan was administered i.v. over 30 min. The planned levels of number of days of administration were: 7, 10, 13, 15 and 17. The dose was individualized according to the patient's individual topotecan clearance observed after the first infusion of each cycle.

RESULTS

Twenty-three patients were enrolled and received 71 cycles of therapy. The 13-day level was defined as the maximum number of days of administration. The main side effects were thrombocytopenia and anaemia, whereas neutropenia was infrequent. The mean (coefficient of variation) observed AUC was 34.6 (21%), and 33.4 (19%) microg/Lxh, for the last day of cycle 1, and of cycle 2, respectively. Confirmed partial responses were observed in one patient with metastatic desmoplastic tumour and in two patients with small round metastatic endocrine carcinoma.

CONCLUSION

The recommended number of topotecan administration is 10 days. Beyond the potential clinical interest of topotecan administered for a 10-day period, this is the first trial showing the feasibility of a phase-I study exploring a number of administrations of daily AUC rather than a total dose in mg/m(2).

Phase I Study of Combined Pegylated Liposomal Doxorubicin with Protracted Daily Topotecan for Ovarian Cancer

PURPOSE

To determine the maximum tolerated dose and dose-limiting toxicity of Doxil with low-dose continuous infusion topotecan and subsequently with low-dose oral topotecan. Other specific aims were preliminary assessment of activity in advanced ovarian and tubal malignancies, pharmacokinetics of oral topotecan, and correlation of response with topoisomerase I and II expression in tumors.

METHODS

Eligible patients had histopathologically documented advanced cancers beyond standard therapy, performance status <2, and adequate organ functions. Doxil (30-40 mg/m2 i.v.) was given on day 1, with topotecan either oral topotecan 0.4 mg/m2 bid for 14 days or continuous infusion topotecan (0.3-0.4 mg/m2/d) for 14 to 21 days, in 28-day cycles. Fifty-seven patients, 23 with epithelial ovarian or tubal cancers were enrolled. Plasma levels of lactone form of topotecan were determined on patients receiving oral topotecan.

RESULTS

Grade 4 neutropenia and thrombocytopenia and grade 3 diarrhea were dose-limiting toxicities at the highest dose levels explored. Doxil (40 mg/m2/day 1) and continuous infusion topotecan at 0.4 mg/m2/days 1 to 14 could be safely given and is the recommended phase II dose. Oral topotecan was limited by low and erratic plasma topotecan levels and frequent gastrointestinal toxicity. Particularly long partial responses and stable disease were observed in patients with epithelial ovarian or tubal cancers. Clinical benefit (objective responses and stable diseases) correlated with elevated expression of both topoisomerases by immunohistochemistry in four of six epithelial ovarian or tubal cancer tumor samples.

CONCLUSION

Doxil with 14-day topotecan infusion is a well-tolerated regimen and suitable for study in platinum-resistant or refractory ovarian or tubal cancers. Frequent gastrointestinal toxicity and/or erratic absorption complicate treatment with a longer topotecan infusion or with oral topotecan, respectively, and these combinations are not recommended.

Efficacy of the novel camptothecin gimatecan against orthotopic and metastatic human tumor xenograft models

PURPOSE

Gimatecan, a novel oral lipophilic camptothecin characterized by favorable features at molecular/cellular level and by a promising profile of preclinical activity, is currently in clinical phase I/II. The aim of the study was to additionally investigate the therapeutic potential of the drug in human tumor xenografts growing in different organs as models representative of tumor growth in the clinical setting.

EXPERIMENTAL DESIGN

The models include two orthotopic central nervous system tumors, two melanomas growing intracranially, and an ovarian carcinoma growing i.p. In addition, gimatecan was tested against experimental lung metastases of two tumor types (lung and ovarian carcinomas). Gimatecan was delivered by oral gavage according to various schedules (daily or intermittent). The time (in days) mice required to show evident signs of disease was used as end point for drug efficacy.

RESULTS

Gimatecan was highly effective in delaying disease manifestations in all tumor systems investigated. In the intracranially growing tumors, a significant time increase (versus control mice) was achieved by the drug administered according to all of the schedules. In addition, almost all treated mice were alive and tumor-free at the end of the experiment in the metastatic models and in the ascitic ovarian tumor. The daily prolonged treatment schedule was the best one.

CONCLUSIONS

In all tumor systems investigated, including orthotopic tumor growth models and lung metastases, the oral administration of gimatecan showed a therapeutic benefit in terms of survival increase. The good oral availability allowed a prolonged daily treatment regimen, which seems the most promising to exploit the therapeutic potential of the drug.

Toxicity of the topoisomerase I inhibitors

The topoisomerase I inhibitors represent a class of antineoplastic agents with a wide spectrum of activity against malignancies. Currently available topo-isomerase I inhibitors are derivatives of the parent compound, camptothecin. Irinotecan is most active against gastrointestinal (GI) tumours, and has predominantly GI and haematological toxicities. Significant pharmacokinetic variability occurs in patients with hepatic dysfunction, particularly those with glucuronidation pathway deficiencies. The toxicity of topotecan is principally haematological with little extramedullary toxicity. Topotecan is well-tolerated in patients with significant hepatic dysfunction; however, patients with even mild renal insufficiency require significant dose reductions. This article discusses the toxicities of these drugs in detail, including the need for dose adjustments in selected patient populations.

Phase 2 trial of prolonged administration of oral topotecan in platinum/taxane-refractory ovarian, fallopian tube, and primary peritoneal cancers

OBJECTIVES

Preclinical and clinical data have demonstrated the importance of schedule in optimizing the cytotoxic potential of topotecan, one of the most active agents in ovarian cancer. The availability of oral topotecan permits the exploration of the clinical utility of prolonged treatment programs employing this drug.

METHODS

Patients with platinum/taxane resistant ovarian and primary peritoneal cancers were treated with oral topotecan at an initial fixed dose of 1.5 mg/day for 5 days, followed by a 2-day break, with treatment continued on this schedule until disease progression or unacceptable toxicities.

RESULTS

Seven patients (median age 61) were entered into this phase 2 trial before further enrollment was discontinued due to the development of excessive side effects (grade 3: fatigue (n = 3); emesis (n = 1), thrombocytopenia with bleeding (n = 1). Two additional patients noted grade 2 fatigue. Four patients experienced reductions in hemoglobin concentrations >4.0 g/dl from baseline during treatment, with two patients requiring red cell transfusions and two receiving recombinant erythropoietin. Three patients developed grade 3 neutropenia, while there were no episodes of > or =grade 2 diarrhea. Three patients exhibited biological evidence of an anti-neoplastic effect of therapy (>50% declines in serum CA-125 levels).

CONCLUSION

Despite the strong theoretical appeal (as well as limited biological evidence of activity in platinum/taxane-refractory disease) associated with prolonging exposure of cycling ovarian cancer cells to topotecan, the specific oral regimen employed in this trial was associated with excessive bone marrow suppression, especially treatment-induced anemia, resulting in an unacceptable incidence of severe fatigue.

A phase II study of liposomal lurtotecan (OSI-211) in patients with topotecan resistant ovarian cancer

OBJECTIVES

To determine the safety and efficacy of a novel topoisomerase I inhibitor, liposomal lurtotecan, in patients with topotecan resistant ovarian cancer.

METHODS

The trial was an open-label phase II study for patients stratified by resistance to either single agent topotecan or to a prior topotecan-containing regimen. Liposomal lurtotecan was delivered at a dose of 2.4 mg/m(2) on Days 1 and 8 of a 21-day cycle. Dose escalations and reductions were allowed based on hematologic toxicity. Patients were evaluated every two cycles for response to liposomal lurtotecan.

RESULTS

Twenty-two women were accrued, with 16 women resistant to single agent topotecan and 6 women resistant to topotecan given in combination with a second chemotherapy agent. Hematologic toxicity consisted of mild to moderate thrombocytopenia, anemia, and neutropenia with mild to moderate gastrointestinal toxicity and fatigue. There were no responses, although eight patients had stable disease.

CONCLUSIONS

Liposomal lurtotecan at this schedule demonstrates moderate hematologic toxicity and no evidence of clinical activity in a group of heavily pretreated women previously exposed to the topoisomerase I inhibitor topotecan. The study of this agent in alternative patient populations or with alternative schedules is ongoing.

Phase I and pharmacokinetic study of topotecan administered orally once daily for 5 days for 2 consecutive weeks to pediatric patients with refractory solid tumors

PURPOSE

We conducted a phase I trial of the injectable formulation of topotecan given orally once daily for 5 days for 2 consecutive weeks (qd x 5 x 2) in pediatric patients with refractory solid tumors.

PATIENTS AND METHODS

Cohorts of two to six patients received oral topotecan at 0.8, 1.1, 1.4, 1.8, and 2.3 mg/m(2)/d every 28 days for a maximum of six courses. Twenty patients (median age, 10.6 years) received a total of 51 courses. Eight patients received topotecan capsules during course 2 only.

RESULTS

Dose-limiting toxicity occurred at 2.3 mg/m(2)/d and consisted of prolonged grade 4 neutropenia (n = 2), grade 3 stomatitis as a result of radiation recall (n = 1), grade 3 hemorrhage (epistaxis) in the presence of grade 4 thrombocytopenia (n = 1), and grade 3 diarrhea in the presence of Clostridium difficile infection (n = 1). Dose-limiting, prolonged grade 4 neutropenia and thrombocytopenia occurred in one patient at 1.4 mg/m(2)/d. Infrequent toxicities were mild nausea, vomiting, elevated liver ALT or AST, and rash. The maximum-tolerated dosage was 1.8 mg/m(2)/d; the mean (+/- standard deviation) area under the plasma concentration-time curve for topotecan lactone at this dosage was 20.9 +/- 8.4 ng/mL. h. The population mean (+/- standard error) oral bioavailability of the injectable formulation was 0.27 +/- 0.03; that of capsules was 0.36 +/- 0.06 (P =.16). Disease stabilized in nine of 19 assessable patients for 1.5 to 6 months.

CONCLUSION

Oral topotecan (1.8 mg/m(2)/d) on a qd x 5 x 2 schedule is well tolerated and warrants additional testing in pediatric patients.

Factors affecting pharmacokinetic variability of oral topotecan: a population analysis

The aim of this study was to characterise the pharmacokinetics of the anticancer agent topotecan, and explore the influence of patient covariates and interoccasion variability on drug disposition. Data were obtained from 190 patients who received the drug as a 30-min infusion (N=72) or orally (N=118). The population model was built with the use of NONMEM to identify candidate covariates, and obtain models for clearance (CL) and volume of distribution. The final models were based on first-order absorption with lag-time (oral data), and a two-compartment model with linear elimination from the central compartment. The Cockcroft–Gault creatinine clearance (CrCl) and WHO performance status (PS) were the only significant covariates: CL=(12.8+2.1 × CrCl) × (1−0.12 × PS). For the volume of distribution, a correlation was found between body weight and the central volume (V1)=0.58 × body weight. Based on the structural models, a limited-sampling strategy was developed with minor bias and good precision that can be applied a posteriori using timed samples obtained at 1.5, and 6 h after the administration of topotecan. In conclusion, a population pharmacokinetic model for topotecan has been developed that incorporates measures of renal function and PS to predict CL. In combination with drug monitoring, the limited sampling strategy allows individualised treatment for patients receiving oral topotecan.

Biweekly 72-Hour 9-Aminocamptothecin Infusion As Second-Line Therapy for Ovarian Carcinoma: Phase II Study of the New York Gynecologic Oncology Group and the Eastern Cooperative Oncology Group

Purpose

To determine the antitumor activity of the novel topoisomerase I inhibitor 9-aminocamptothecin (9-AC) given over 72 hours every 2 weeks in patients with ovarian carcinoma previously treated with one platinum-containing regimen.

Patients and Methods

Patients with ovarian carcinoma who received one prior platinum-containing regimen were eligible. Patients were stratified based on whether their disease was measurable, or nonmeasurable but assessable. 9-AC 35 μg/m2/h was administered by continuous infusion for 72 hours every 2 weeks via ambulatory pump.

Results

Sixty patients were entered, 32 with measurable and 28 with nonmeasurable but assessable disease. Ten (16.7%) of 60 patients responded (95% CI, 7.2% to 26.1%), with four complete responses and six partial remissions. The response rate for patients with measurable and nonmeasurable but assessable disease was 22% (95% CI, 7.6% to 36.2%) and 10.7% (95% CI, 2.3% to 28.2%), respectively. None of the responders were platinum-resistant. Nineteen patients (32%) had stable disease. The major toxicities were hematologic, with 25% of patients having grade 3 and 35% having grade 4 neutropenia, including five episodes of febrile neutropenia, 17% having grade 3 to 4 thrombocytopenia, and 27% having grade 3 to 4 anemia. Nonhematologic toxicity included grade 3 to 4 nausea (27%) and grade 3 to 4 vomiting (12%).

Conclusion

This phase II multicenter trial of biweekly 72 hour 9-AC infusion as second-line therapy for ovarian cancer demonstrates comparable activity to standard approved agents in patients with both measurable and nonmeasurable but assessable disease. Toxicity consists mainly of moderate but controllable myelosuppression. Further studies combining 9-AC with other agents active in ovarian cancer for use as second-line therapy are warranted.

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.

OSI-211, a novel liposomal topoisomerase I inhibitor, is active in SCID mouse models of human AML and ALL

OSI-211 (liposomal lurtotecan), was evaluated using several different dose schedules (1mg/kg, d1-5, 1.75 mg/kg d1, 3, 5 and 6 mg/kg d1, 8) in severe combined immunodeficient (SCID) mouse models of acute myelogenous leukemia (AML) and acute lymphocytic leukemia (ALL) with early treatment (ET, days 6-8) or late treatment (LT, days 15-19), examining early and advanced disease, respectively. Due to the aggressive nature of the Molt-4 model, the ET and LT were accelerated to day 3 or 4 and day 8 post-implant, respectively. For each model, 2 x 10(7) (KBM-3B) or 1 x 10(7) (Molt-4, HL-60 and CEM) leukemia cells were injected intravenously into the tail vein. Each control and test group consisted of eight animals. All three schedules (1mg/kg qd1-5, 1.75 mg/kg d1, 3, 5 and 6 mg/kg d1, 8) increased the life span of OSI-211 treated animals in each model, with a tendency toward improved efficacy with the 6 mg/kg d1, 8 schedule. As a result, the activity of the 6 mg/kg d1, 8 schedule is detailed for each model. ET significantly (P<0.005) increased survival in the KBM-3B model with 86% long-term survivors (LTS). Using PRC analysis, human beta-globin gene sequences in one or several tissues were amplified in all but 3 LTS, suggesting minimal residual disease in 26 of the 29 LTS. LT also significantly (P<0.005) improved average life span in the KBM-3B model, with an average ILS=196+/-11% and one LTS. Treatment of HL-60 leukemia animals significantly (P<0.005) increased life span, with an ILS=213+/-9% and two LTS for ET, and with an ILS=219+/-4% and no LTS for LT. Treatment of Molt-4 animals, the most aggressive leukemia model tested, significantly (P<0.005) increased life span, with an average ILS=181+/-3% and no LTS for ET and an average ILS=172+/-1% with no LTS for LT. In the CEM model, ET resulted in a significantly (P<0.005) improved ILS=244+/-24% with one LTS. In comparison to OSI-211, treatment with DaunoXome, the liposomal formulation of daunorubicin, a drug with clinical efficacy in AML and ALL, had no effect on survival in the KBM-3B, nor Molt-4 A4 leukemia models when administered at its maximum or near maximum tolerated doses of 3mg/kg d1, 8. These data demonstrate that OSI-211 has potent antileukemia activity in preclinical SCID mouse AML and ALL leukemia models, supporting the clinical investigation of OSI-211 for hematological malignancies.

Phase II evaluation of three-day topotecan in recurrent platinum-sensitive ovarian carcinoma: a gynecologic oncology group study

BACKGROUND

Topotecan, administered intravenously at a dose of 1.5 mg/m(2) per day for 5 days every 21 days, is an established regimen in the treatment of recurrent ovarian carcinoma. Alternate dosing strategies have sought to improve toxicity. The authors evaluated the tolerability and antitumor activity of a 3-day topotecan regimen.

METHODS

A multicenter Phase II study, which included patients with platinum-sensitive ovarian carcinoma, was conducted. Patients were to receive an intravenous dose of topotecan of 2.0 mg/m(2) per day for 3 days every 21 days until disease progression or unacceptable toxicity occurred. Doses were modified in 0.25-mg/m(2) increments based on tolerability. Granulocyte-colony-stimulating factor support was used as necessary.

RESULTS

From February to June 2000, 30 patients were enrolled. Their median age was 56 years (range, 41-81 years). Twenty-nine patients were evaluable for toxicity and efficacy. A median of 5 courses (range, 1-11 courses) of topotecan was administered. Eighteen of 30 (60%) patients experienced Grade 4 neutropenia. There was one report each of Grade 4 thrombocytopenia, anemia, and gastrointestinal toxicity (grading performed according to National Cancer Institute Common Toxicity Criteria). Ten patients developed Grade 3 leukopenia and 9 had Grade 3 neutropenia. Serious nonhematologic events were rare. There were 2 (7%) complete and 2 (7%) partial responses, for an overall response rate of 14%. Sixteen (55%) patients had stable disease and 9 (31%) experienced disease progression.

CONCLUSIONS

A 3-day regimen of topotecan at a dose of 2.0 mg/m(2) per day was generally well tolerated, although the response rate was lower than that for the standard 5-day schedule.

Workshop: options for therapy in ovarian cancer

Current and future options for sequential therapy for first and subsequent relapses in ovarian cancer were discussed in three workshops centered around a number of case studies. The participants included investigator oncologists from the USA, Europe, and Asia. For a platinum-resistant patient, topotecan or pegylated liposomal doxorubicin was considered the treatment of choice at first relapse. Since optimal tolerability with topotecan is achieved in less heavily pretreated patients, it may be best to use it earlier rather than later in the treatment schedule. For subsequent relapse within 6 months, most clinicians would use liposomal-encapsulated doxorubicin if the prior treatment had been topotecan and vice versa. Alternative agents may be considered with the aim of achieving symptom palliation rather than prolongation of survival. For late relapse after optimal debulking and treatment with carboplatin/paclitaxel, retreatment with carboplatin/paclitaxel (possibly after further surgery) was considered the best approach in platinum-sensitive patients. For first relapse after 10 months in a suboptimally debulked patient, retreatment with carboplatin/paclitaxel was also considered a viable option. Alternatively, single-agent therapy with paclitaxel, pegylated liposomal doxorubicin, or topotecan may be appropriate to prolong the platinum-free interval. For second relapse, oral etoposide was felt to be useful. Treatment for subsequent relapses included gemcitabine, docetaxel, and agents above not previously utilized. Topotecan tolerability and convenience may be improved by employing a lower dose, shorter schedule, 21-day continuous infusion or weekly dosing in relapsed/refractory disease. The progression-free interval may be extended by continuing topotecan until disease progression in patients with stable disease or by topotecan consolidation therapy in treatment responders.

Topotecan is an active agent in the first-line treatment of metastatic or recurrent endometrial carcinoma: Eastern Cooperative Oncology Group Study E3E93

PURPOSE

To determine the clinical activity and the toxicity profile of the topoisomerase-I inhibitor, topotecan, in women with recurrent or advanced endometrial carcinoma.

PATIENTS AND METHODS

A prospective, phase II clinical trial was initiated by the Eastern Cooperative Oncology Group (ECOG). Patients had histologically confirmed advanced or recurrent endometrial carcinoma, measurable disease, no prior cytotoxic therapy, an ECOG performance status of 0 to 2, and evidence of disease progression while on progestins or after radiation therapy. Topotecan was administered at 1.5 mg/m(2) (or 1.2 mg/m(2) for patients with prior pelvic radiation) intravenously daily for 5 days every 3 weeks.

RESULTS

A total of 44 patients were enrolled; 42 were eligible. The study was suspended because of unexpected toxicities, primarily sepsis and bleeding. After toxicity review, the study was reopened using lower doses of topotecan (1.0 mg/m(2) or 0.8 mg/m(2) for patients with prior radiation therapy). In addition, prophylactic use of growth factors was allowed after the first cycle, and patients with performance status of 2 were excluded. The major toxicities were hematologic and gastrointestinal. Among the 40 assessable patients, there were three (7.5%) complete responders and five partial responders (12.5%), for an overall response rate of 20%. The median duration of response was 8.0 months and of overall survival was 6.5 months.

CONCLUSION

Topotecan is an active agent for the treatment of advanced endometrial carcinoma. At the doses and schedules initially used, toxicities were unacceptable; however, at the modified doses, toxicities were acceptable and clinical activity was preserved.

The use of continuous infusion topotecan in persistent and recurrent ovarian cancer

We retrospectively review our experience with continuous infusion topotecan for the treatment of persistent or recurrent ovarian cancer in this paper. Nine patients were identified who were treated at the University of California Los Angeles Medical Center between January 1997 and December 1999 using a 14-21 day continuous infusion schedule (0.3-0.7 mg/m2/d). Dose adjustments were performed for grade 3-4 toxicities and treatment was discontinued for persistent severe toxicity or progressive disease. Response to treatment was analyzed and stratified by platinum refractory, resistant, and sensitive disease. A total of 41 treatment cycles were given to nine patients with a median of five per patient (range 1-11). Median follow-up was 8 months. There were two partial responses (22%) and four patients had stable disease (44%), which included two patients with platinum-refractory tumors. No grade 3 or 4 hematologic toxicities were observed. However, two patients suffered grade 3 gastrointestinal toxicity during the first cycle leading to discontinuation of topotecan administration. There was no cumulative toxicity. Topotecan administered by continuous infusion demonstrated response rates comparable to other dosing schedules with minimal hematologic toxicity. Treatment of patients with persistent or recurrent ovarian cancer with continuous infusion topotecan warrants further investigation.

Emerging role of topotecan in front-line treatment of carcinoma of the ovary

The conventional front-line chemotherapy strategy for advanced epithelial ovarian carcinoma has become adjuvant administration of platinum (carboplatin and cisplatin), either alone or, most often, in combination with a taxane. However, a number of active agents have been identified in phase II/III trials of second-line and salvage ovarian cancer patients that may augment this front-line strategy. One agent, topotecan, has antitumor activity comparable with paclitaxel in patients with recurrent ovarian cancer and is an established treatment in second-line or salvage settings. Additionally, its mechanism of action is different from paclitaxel and is nonoverlapping. These properties, coupled with the in vitro synergy observed in tumor models among topotecan, paclitaxel, and platinum, have provided the rationale for investigators to examine topotecan in front-line ovarian cancer therapy. A number of strategies for incorporating topotecan into front-line therapy are under active investigation, including the replacement of paclitaxel with topotecan, a triplet regimen with cisplatin or carboplatin and paclitaxel, a consolidation regimen consisting of several courses of a platinum agent and paclitaxel followed by several courses of topotecan, and a sequential doublet regimen in which patients receive platinum in every course as part of a doublet with alternating or sequential topotecan and paclitaxel. Preliminary data from ongoing clinical trials of these new regimens show favorable response rates and generally manageable toxicity profiles. This review summarizes the preliminary clinical findings associated with the four strategies and outlines ongoing and future randomized studies of topotecan in front-line ovarian cancer.

Alternate dosing schedules for topotecan in the treatment of recurrent ovarian cancer

Topotecan has demonstrated efficacy in the treatment of both platinum-sensitive and platinum-resistant recurrent ovarian cancer. However, the optimal dosing for topotecan has not been established. The standard dosing regimen is 1.5 mg/m(2)/day on days 1-5 of a 21-day cycle, with response rates ranging from 13%-33%. Although the resulting hematologic toxicities are reversible and noncumulative, this schedule is associated with significant myelosuppression. Ongoing clinical phase I and II trials have evaluated alternative dosing schedules such as the 21-day 24-hour continuous intravenous (c.i.v.), the 3-day i.v. bolus, the weekly 72-hour c.i.v., the weekly 24-hour c.i.v., and the weekly bolus i.v. regimens. Prolonged exposure to topotecan has been shown to increase the efficacy of topotecan, whereas shorter regimens decrease exposure to the drug and therefore decrease toxicity. Preliminary studies investigating the weekly bolus i.v. regimen have demonstrated response rates comparable with those achieved with the standard dosing regimen, with a lower frequency of severe toxicity. Although randomized, controlled comparative trials are necessary to determine relative efficacy, results from studies utilizing other alternative regimens are less encouraging, especially for lower-risk patients with platinum-sensitive ovarian cancer who are likely to tolerate higher doses of topotecan. Optimizing the dosing regimen will also increase the quality of life for the patient through increased efficacy, decreased toxicity, and increased convenience of administration. Continued investigation of the weekly i.v. bolus is needed to fully elucidate the contribution of this regimen to the current armamentarium used in the treatment of patients with relapsed ovarian cancer.

Irinotecan: mechanisms of tumor resistance and novel strategies for modulating its activity

Camptothecins are broad-spectrum anticancer drugs that specifically target DNA topoisomerase I (Topo I). The formation of a cleavable drug-Topo I-DNA complex results in lethal double-strand DNA breakage and cell death. However, de novo or acquired clinical resistance to camptothecins is common. Studies of the camptothecin analog irinotecan suggest the following general mechanisms of resistance: (i) variable levels of the enzymes involved in the conversion of irinotecan; (ii) reduced cellular accumulation from active drug efflux; (iii) reduced levels of Topo I expression; (iv) alterations in the structure of Topo I from different mutations; (v) alterations in the cellular response to camptothecin-Topo I-DNA complex formation, which involves proteasome degradation of Topo I and/or enhanced DNA repair; and (vi) activation of the transcription factor nuclear factor kappa B by DNA damage and subsequent suppression of apoptosis. Multiple approaches using pharmacological and biological modulation to circumvent the above mechanisms of resistance have been incorporated into ongoing clinical trials and are expected to enhance the antitumor activity of irinotecan and reduce its systemic toxicity.