Weekly topotecan in the management of ovarian cancer

Antibody drug conjugates: The dos and don'ts in clinical development

Antibody Drug Conjugates (ADCs) entered clinical trials in the mid 1990s to selectively deliver cytotoxic chemotherapy to cancer cells with the goal to increase the antitumor activity and decrease normal tissue toxicity. Over nearly 30 years of development the ADC platform has become established with now 11 approved agents and many more in the pipeline. This review is designed to highlight some of the problems and solutions encountered in clinical development as well as provide practical instruction to both clinical investigators on the efficient protocol design for ADCs and the lessons learned.

Update on the Treatment of Recurrent Ovarian Cancer

Ovarian cancer is the leading cause of death for all gynecologic malignancies in developed countries, largely owing to the late stage of diagnosis. Despite response to initial surgery and chemotherapy, more than 65% of patients will have recurrent or persistent diseases. Approximately 50% of patients with recurrent ovarian cancer are asymptomatic. Recurrences are often diagnosed using a combination of tests, including cancer antigen 125, computed tomography, magnetic resonance imaging and positron emission tomography scan. The most significant prognostic factor among women with recurrent ovarian cancer is the length of time from initial diagnosis to recurrence. Treatment of recurrent ovarian cancer involves chemotherapy, with or without surgery. In selected patients, secondary cytoreductive surgery might significantly improve survival. Radiotherapy may have a role in the treatment of a small group of patients with localized symptomatic masses. New treatment modalities for women with recurrent ovarian cancer are needed, as none of the available treatments are curative.

Epithelial ovarian cancer in older women: defining the best management approach

Epithelial ovarian cancer is a cancer of older women. In fact, almost half of women diagnosed with ovarian cancer will be older than age 64, and 25% will be older than age 74. Therefore, it is crucial to examine the available data in older populations to optimize the therapeutic approach without negatively affecting the quality of life permanently. Unfortunately, little prospective data are available in this under-represented population of women. Although ovarian cancer traditionally has been approached with aggressive cytoreductive surgery, older patients may benefit from a less aggressive surgical approach and, in some cases, may be candidates for neoadjuvant chemotherapy followed by an interval cytoreduction. Modalities do exist for assessing an older woman's ability to tolerate surgery and chemotherapy, and these tools should be familiar to clinicians who are caring for this population of women in making treatment decisions. Ongoing planned trials to evaluate pretreatment assessment for older patients will provide objective, feasible, clinical tools for applying our treatment-based knowledge. Future trials of both surgery and chemotherapy, including a focus on the sequence of these two treatment modalities, are crucial to guide decision making in this vulnerable population and to improve outcomes for all.

Considerations regarding the administration of systemic therapy for elderly patients with ovarian cancer

To improve the benefit and tolerability of cancer treatment, we must develop new geriatric-specific trials, better assessment tools, and encourage enrollment of older patients in clinical trials. Age is a strong predictor of survival in ovarian cancer and often influences the treatment plan. Elderly patients, broadly defined as older than age 65 years, are commonly not offered participation in clinical research or provided with substandard chemotherapy or surgical options. Because first-line, platinum-based chemotherapy with cytoreductive surgery is a potentially curative modality, all standard treatment options should be explored (intravenous, neoadjuvant, and/or intraperitoneal chemotherapy). However, one must balance the specific needs of the older patient and be aware of the increased risk of side effects. To be mindful and respectful, the oncologist should clearly define the goals (palliative vs. curative) and specific risks of treatment to patients and their families. As the field of geriatric oncology evolves and prospective trials tailored to older women with ovarian cancer are developed, specific guidelines will ultimately assist in these difficult decisions.

Treatment and trials: ovarian cancer in older women

Ovarian cancer (OC) is a disease of elderly women. The disease spreads insidiously and presents at an advanced stage at initial diagnosis for most patients. Several groups reported at least a two-fold increased risk of death in women older than 65. Various theories have been proposed to explain this survival disparity in older women, including: (1) more aggressive cancer with advanced age, (2) inherent resistance to chemotherapy, (3) individual patient factors such as multiple concurrent medical problems, and (4) physician and health-care biases toward the elderly that lead to inadequate surgery, less than optimal chemotherapy, and poor enrollment in clinical trials. As a result of this high clinical variability, oncologists need to be more familiar with the comprehensive geriatric assessment to better identify vulnerable patients at higher risk of complications. Several geriatric tools are available to assess the physiologic and functional capacities of older patients and to better individualize treatment. This paper gives an overview of the management of elderly patients with OC, in particular the integration of chemotherapy, surgery, and geriatric assessment to improve treatment tolerance and survival outcomes.

A phase II study of higher dose weekly topotecan in relapsed small-cell lung cancer

BACKGROUND

Five-day topotecan is approved by the US Federal Drug Administration (FDA) for sensitive relapsed small-cell lung cancer (SCLC). We previously found that 4 mg/m(2) intravenous (I.V.) weekly dosing resulted in low-grade 3/4 toxicity but an overall response rate (ORR) < 10%. We hypothesized that higher topotecan dosing could improve ORR without significantly increasing toxicity.

PATIENTS AND METHODS

This multicenter phase II trial sought a 25% ORR (α = 0.04; β = 0.20). Eligible patients (sensitive or refractory relapsed SCLC; Eastern Cooperative Oncology Group [ECOG] performance status [PS] 0-1; measurable disease) received weekly topotecan (6 mg/m(2) I.V. for 6 weeks) and were restaged every 8 weeks.

RESULTS

Baseline characteristics were N = 38, enrolled 5/2006-10/2007; median age 64 years (range, 35-82), 47% female, 74% ECOG PS 1, 50% refractory relapsed SCLC. The median follow-up was 15 months (range, 12-24 months). No patients received all planned therapy; only 1 patient was able to receive all planned treatment in cycle 1 because of hematologic toxicity and progressive disease (PD). Among all patients, ORR was 8% (95% confidence interval [CI], 2%-21%), 24% had stable disease, and disease in 47% progressed. Among sensitive relapsed patients ORR was 16% (95% CI, 3%-40%) with no complete responses; median response duration was 3.3 months. Five (26%) patients had stable disease; 8 (42%) patients had PD. Among sensitive relapsed patients, the median time to progression (TTP) and overall survival (OS) was 2.5 months and 8.6 months, respectively. Among refractory relapsed patients there were no ORRs, and median TTP and OS were 1.5 months and 3.7 months, respectively. Grade 3/4 toxicities (> 10%) included neutropenia (53%), leukopenia (42%), thrombocytopenia (37%), anemia (13%), fatigue (13%), and pain (13%). There were no treatment-related deaths.

CONCLUSION

Weekly topotecan (6 mg/m(2) I.V.) is not feasible because of hematologic toxicity and does not improve efficacy in patients with relapsed SCLC.

An open-label, single-arm Phase II study of intravenous weekly (Days 1 and 8) topotecan in combination with carboplatin (Day 1) every 21 days as second-line therapy in patients with platinum-sensitive relapsed ovarian cancer

OBJECTIVE

To evaluate clinical activity of weekly topotecan plus carboplatin in patients with platinum-sensitive recurrent ovarian, fallopian tube, or peritoneal carcinoma.

METHODS

An open-label, single-arm, multicenter Phase I/II study. Phase II was the activity assessment phase, with overall response rate (ORR) as the primary endpoint. Eligible patients (females aged ≥18 years) received study treatment at the maximum-tolerated dose (MTD) identified in Phase I: intravenous topotecan 2.5mg/m(2) (Days 1 and 8), followed by carboplatin AUC 5 (Day 1), every 21 days. A two-stage Green-Dahlberg design was used to assess efficacy of treatment. An ORR of ≤30% was required to conclude that treatment was ineffective.

RESULTS

Twenty-two patients in Phase I permitted identification of the MTD. In Phase II, 55 patients (median age 64.0 years) were enrolled and included in the intent-to-treat population. There were six complete responses (10.9%) and 11 partial responses (20.0%), giving an ORR of 30.9% (17 patients; 95% CI: 18.7%, 43.1%). Median time to response and progression-free survival were 6.57 weeks (95% CI: 5.86, 12.57) and 44.29 weeks (95% CI: 36.14, 52.14), respectively. Grade 3/4 hematological toxicity caused dose reductions, treatment delays and study discontinuation. Neutropenia (Grade 3: 29%; Grade 4: 11%) was the most common hematological adverse event (AE). Fatigue (71%) and nausea (71%) were the most common drug-related non-hematologic AEs.

CONCLUSIONS

This study showed an acceptable benefit-risk profile for topotecan plus carboplatin. Further studies using alternative dose levels could help define an optimal dosing schedule for this treatment combination in patients with platinum-sensitive recurrent disease.

A phase II trial of carboplatin and weekly topotecan in the first-line treatment of patients with extensive stage small cell lung cancer

BACKGROUND

Carboplatin and topotecan are commonly used in the treatment of small cell lung cancer (SCLC); however, there are no data for this combination in the first-line setting using weekly topotecan. In this multicenter, community-based phase II trial, we evaluated carboplatin and weekly topotecan in the previously untreated patients with extensive stage SCLC.

METHODS

This trial was designed to achieve an objective response rate (ORR) of 70% (alpha = 0.05; beta = 0.20); secondary aims were to assess time to progression, toxicity, and overall survival (OS). Patients with Eastern Cooperative Oncology Group performance status 0 to 1, measurable disease, and adequate organ function were eligible.

TREATMENT

carboplatin area under the concentration-time curve = 5 (intravenous) on day 1 and topotecan 4 mg/m(2) (intravenous) on days 1 and 8, every 21 days for up to six cycles, with restaging every 6 weeks (per RECIST).

RESULTS

Between June 2006 and November 2008, 61 patients were enrolled. The median follow-up is 40 weeks (range 27-109 weeks). Patient characteristics were as follows: median age 67 years (range 40-84 years); male, 53%; and Eastern Cooperative Oncology Group performance status 0, 28%. Complete responses were seen in two patients and partial responses in 33 patients; ORR was 57% (95% confidence interval [CI] 44-70). Stable disease was seen in 12 patients (20%), and progressive disease was seen in two patients (3%). The median time to progression was 5.5 months (95% CI 4.0-6.3 months). The median OS was 8.5 months (95% CI 7.2-11.4 months). One-year OS was 29%. Grade 3/4 toxicity in >5%: neutropenia (66%), thrombocytopenia (48%), leukopenia (40%), anemia (30%), fatigue (13%), dehydration (8%), infection (8%), and pain (7%).

CONCLUSIONS

The ORR achieved with carboplatin and weekly topotecan was less than the anticipated rate of 70%; however, it was comparable with historical rates seen with other platinum doublets in the first-line extensive stage SCLC setting. This regimen was generally well tolerated, with myelosuppression as its primary toxicity.

Feasibility of extension of platinum-free interval with weekly bolus topotecan and subsequent platinum retreatment outcomes in recurrent ovarian cancer

PURPOSE

The goal of this study was to evaluate the outcomes and response in a cohort of patients with presumed platinum-sensitive disease who were subsequently retreated with platinum after receiving weekly bolus topotecan at the time of initial recurrence.

METHODS

A retrospective review of our institutional databases identified a cohort of platinum-sensitive women with recurrent ovarian and peritoneal carcinoma. Antitumor responses and toxicities were assessed for patients retreated with platinum-based chemotherapy following weekly bolus topotecan (4 mg/m²).

RESULTS

Twenty-six patients (median age 63 years, range 45-80 years) were identified. Advanced stage (III/IV) ovarian carcinoma was most common (96%). Residual disease after primary cytoreductive surgery was less than 1 cm in 65% of the cohort. Platinum retreatment was well tolerated. Grade 3 neutropenia occurred most commonly (8%) without any episodes of grade 4 myelotoxicity. Fatigue (12%) and hypersensitivity reaction (15%) were the most common non-hematologic toxicities during platinum retreatment. Of the 26 patients, 5 (19%) had a complete response, 5 (19%) had a partial response, 10 (39%) had stable disease, and 6 (23%) had progressive disease. Thirty-nine percent of patients with stable or progressive disease during weekly bolus topotecan responded to subsequent platinum retreatment. Response to platinum retreatment, treatment-free interval, and platinum-free interval was significant prognosticators for survival (P < 0.05).

CONCLUSION(S)

The results of this retrospective analysis suggest that weekly bolus topotecan, as intervening non-platinum, may result in acceptable toxicities and response rates during platinum retreatment in platinum-sensitive relapsed ovarian or peritoneal carcinoma.

A phase II study of weekly topotecan and docetaxel in heavily treated patients with recurrent uterine and ovarian cancers

OBJECTIVES

A phase II trial designed to evaluate the safety and efficacy of weekly topotecan and docetaxel in heavily treated patients with recurrent uterine or epithelial ovarian cancers.

METHODS

Eligible patients with recurrent epithelial ovarian or uterine cancers were treated with weekly topotecan 3.5 mg/m(2) and docetaxel 30 mg/m(2) for 3 consecutive weeks. Cycles were repeated every 4 weeks for 6 cycles or until evidence of disease progression, unacceptable toxicity, or death. Response was assessed as per RECIST or Rustin's criteria. Time to best response and overall survival were calculated using Kaplan-Meier statistical methods.

RESULTS

Twenty-seven patients registered, of which 24 were evaluable for response. The majority of patients had received 2 prior chemotherapy regimens. Of the total 86 cycles of chemotherapy that were administered, there were three grade 4 (all neutropenia) and ten grade 3 toxicities. Six of the grade 3 non-hematologic toxicities were unrelated to treatment. There were 8 dose delays and 4 dose reductions. The overall response rate was 25% (95% CI: 7.7%-42.3%, 8% CR, 17% PR), and 38% of the patients had clinical benefit (95% CI: 18.1%-56.9%; CR+PR+13% SD). The median duration of response was 8.5 months (range 3-19 months). The median overall survival was 18.5 months (range 1.8-50.7 months).

CONCLUSION

The combination of weekly topotecan and docetaxel has clinical benefit and is well tolerated in this heavily treated patient population. Patients with platinum-resistant tumors had clinical benefit and should be considered for further study with this regimen.

A phase II, multicenter trial of weekly topotecan in patients with recurrent platinum-sensitive epithelial cancers of the ovary and peritoneum

The purpose of this study was to evaluate the response rate and toxicity of weekly topotecan in patients with recurrent platinum-sensitive epithelial cancers of the ovary and peritoneum. Thirty-nine platinum-sensitive recurrent ovarian cancer patients received topotecan (4 mg/m(2)) intravenously day 1, day 8, day 15, every 28 days. Colony-stimulating factors were excluded from the study. Clinical response was assessed by clinical, serologic, and radiographic measures at the conclusion of cycle four. Patients received 136 cycles of topotecan (median = 3; range 1-6) and were evaluated for response and toxicity. Median number of prior regimens was one. Grade 3/4 neutropenia developed in 3 (7.7%) patients. Grade 3 thrombocytopenia was seen in one (2.6%) patient, with no incidence of grade 4 thrombocytopenia. There was no evidence of grade 3 anemia, but one patient (2.6%) was associated with grade 4 anemia. There was no grade 3 or 4 neuropathy. We encountered 18 dose reductions following less than or equal to grade 2 myelosuppression, necessitating the removal of eight (20.5%) patients prior to cycle four. Twenty-one (53.8%) patients were removed from the study due to disease progression. Following the completion of cycle four, four (10.3%) patients demonstrated stable disease and four (10.3%) patients exhibited a partial response. There were no complete responses. Median disease-free survival was 12 weeks. Weekly topotecan (4 mg/m(2)) demonstrated modest activity and was moderately well tolerated. However, the significant number of dose reductions and high incidence of patients who demonstrated disease progression suggests additional modifications with this specific regimen are necessary.

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.

The current treatment of recurrent ovarian cancer

Contemporary management of recurrent ovarian, primary peritoneal, and fallopian tube cancers has continued to evolve and now offers women the hope of extended survival with an improved quality of life. Platinum continues to be the single most active agent in the treatment of ovarian cancer, but acquired resistance to platinum often emerges. Fortunately, a number of novel agents and treatment strategies have been developed to meet the goals of ameliorating symptoms while extending survival. Classically, patients have been treated based upon the interval from last platinum administration during front-line therapy until time of recurrence. This review focuses upon the current treatment strategies used for platinum-refractory, platinum-resistant, and platinum-sensitive patients. The incorporation of targeted biologic agents is also discussed, along with the role of secondary cytoreduction. It is hoped that the results of future and ongoing clinical trials will offer further advances in the treatment of this devastating disease.

Phase II evaluation of a 3-day infusion of topotecan in patients with recurrent ovarian or primary peritoneal cancer

OBJECTIVE

To assess the efficacy and toxicity profile in patients treated with topotecan at 2.0 mg/m2/day x 3 days every 3 weeks.

MATERIALS AND METHODS

Eligibility criteria included patients with recurrent primary peritoneal or epithelial ovarian cancer with > or =6 months elapsed from time of prior platinum treatment. Patients were required to have a performance status of < or =2 and normal hepatic and renal function. Response to therapy and toxicity was assessed using standard criteria. Chi-square and Student's t tests were used as appropriate. Survival was assessed with Kaplan-Meier method.

RESULTS

All 40 patients enrolled were assessable for response. The mean age of the patients was 63.2 years (range 43-85). Median time to progression from initial treatment was 11.8 months. A total of 286 cycles of chemotherapy were administered with an average of 7.1 cycles per patient. Overall median time to progression (TTP) with 3-day topotecan treatment was 21 weeks (range 6-43 weeks). Of the 33 patients with measurable disease, 24% (11-42%, 95% CI) demonstrated a response. Seven patients had CA-125 evaluable disease with a response of 43% (10-89%, 95% CI). Median progression-free survival (PFS) was 16 weeks (range 12-21 weeks, 95% CI). Median overall survival was 106 weeks (range 76-117 weeks, 95% CI). Assessment of toxicity by patient showed 90% demonstrating grade 3/4 neutropenia with the vast majority being uncomplicated. No severe non-hematological toxicity was observed.

CONCLUSION

Administration of topotecan as a 3-day regimen is feasible with demonstrable activity and tolerable toxicity. Critical comparison to the 5-day regimen in a randomized fashion is warranted.

"Dose dense" chemotherapy in ovarian cancer

In essence, dose densification is "accelerated therapy" (a commonly used phrase in radiotherapeutics) and is a form of dose intensification because the amount of drug per unit time (dose intensity = mg/m(2)/week) is increased. There is general consensus that increasing platinum dose intensity in ovarian carcinoma has not been proven despite a dozen or more randomized trials evaluating up to twofold increases in dose intensity. Few randomized trials in ovarian carcinoma have compared weekly "dose dense" chemotherapy with more conventional dosing schedules although there are plenty of phase II studies. In these, dose densification of single agent therapy, for some drugs at least, appears to be relatively well tolerated, with encouraging levels of activity in patients purportedly refractory to the same agents when scheduled in the standard way. However, many studies ostensibly evaluating "dose density" do not actually evaluate this entity, but actually split the standard 3-weekly dose into weekly fragments thus maintaining the same dose intensity. Furthermore, as the aim of treatment in recurrent ovarian cancer is palliation, weekly treatments are less convenient, are probably less cost effective, and have different dose-limiting toxicities. This article will review the clinical data supporting dose density as a therapeutic maneuver in ovarian cancer.

Role of chemotherapy in the management of epithelial ovarian cancer

The management of ovarian cancer continues to provide major challenges and debates about optimal treatment. For first-line therapy there remain discussions about optimal chemotherapy for early disease, the use of taxanes as standard for advanced newly diagnosed patients, whether there is a definite role for neoadjuvant chemotherapy and the question of maintenance treatment. For relapsed disease, the management hinges around the distinction between platinum-sensitive and -resistant cancer, and the recent AGO-2.5 and ICON-4 studies suggest that treating with carboplatin and paclitaxel or carboplatin and gemcitabine is recommended. Intraperitoneal chemotherapy remains an enigma with at least three studies showing survival advantage; however, there has been no move to incorporate it into standard management of those patients who achieve complete remission after first-line chemotherapy. Finally, neoadjuvant chemotherapy prior to debulking surgery is the subject of several ongoing clinical trials and may turn out to be one of the most important developments since the concept of interval debulking surgery was established and proven in Europe.

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.

A phase I trial of gemcitabine and topotecan in previously treated ovarian or peritoneal cancer: a Gynecologic Oncology Group study

OBJECTIVE

To determine the maximum tolerated dose (MTD) of the combination of gemcitabine and topotecan in women with previously treated epithelial ovarian, peritoneal, or fallopian tube cancer.

METHODS

Patients with recurrent or persistent cancer after treatment with a platinum and paclitaxel-containing regimen were eligible for this study. Initial treatment was gemcitabine at a dose of 800 mg/m(2) on days 1, 8, and 15 and topotecan at a dose of 0.5 mg/m(2) on days 2-5, with cycles repeated every 28 days. Dose escalations were planned first for topotecan (Cohort I, Dose Levels 1-5) then for gemcitabine (Cohort II, Dose Levels 6-9) until the MTD was reached.

RESULTS

Ten patients received a total of 29 cycles. When none of the first four patients could complete therapy as prescribed due to toxicity, doses for each drug were reduced by 1 day. The next six patients were treated at the modified schedule of gemcitabine days 1 and 8 and topotecan days 2-4 (Dose Level -1). Despite this modification, dose-limiting toxicities including neutropenia, thrombocytopenia, and stomatitis occurred at Dose Level -1, and the study was closed early.

CONCLUSIONS

At both the initial dose schedule and an attenuated schedule, the combination of gemcitabine and topotecan produced dose-limiting toxicities in women with previously treated epithelial ovarian or peritoneal cancer.

A review of selected anti-tumour therapeutic agents and reasons for multidrug resistance occurrence

It is assumed that proteins from the ABC family (i.e., glycoprotein P (Pgp)) and a multidrug resistance associated protein (MRP) play a main role in the occurrence of multidrug resistance (MDR) in tumour cells. Other factors that influence the rise of MDR are mechanisms connected with change in the effectiveness of the glutathione cycle and with decrease in expression of topoisomerases I and II. The aim of this review is to characterize drugs applied in anti-tumour therapy and to describe the present state of knowledge concerning the mechanisms of MDR occurrence, as well as the pharmacological agents applied in reducing this phenomenon.

Costs of treatment and outcomes associated with second-line therapy and greater for relapsed ovarian cancer

OBJECTIVES

Most women with epithelial ovarian cancer (EOC) will develop disease progression or recurrence with resistance to platinum therapy. We report overall costs and treatment outcomes associated with topotecan or gemcitabine administration in platinum- and paclitaxel-resistant EOC patients.

METHODS

Patients who received topotecan (n = 51) or gemcitabine (n = 56) as second-line therapy or greater for platinum- and paclitaxel-resistant EOC were retrospectively identified. Per patient costs for each regimen were determined and compared.

RESULTS

The mean total direct cost per cycle per patient of gemcitabine was $2732.28, with a median total direct cost per cycle of $1382.73. The mean total direct cost per cycle per patient of topotecan was $7832.07, with a median total direct cost per cycle of $4219.02. By comparison of the means, total direct cost per cycle per patient was significantly more expensive for topotecan (P = 0.001). Fifty-six patients received a total of 415 cycles of gemcitabine, median 5 cycles per patient (range, 1-59). Thirteen (23.2%; 95% CI, 11.9-34.5%) of 56 patients displayed clinical benefit, with median PFS of 1.8 months and median overall survival (OS) of 8.2 months. Fifty-one patients received topotecan, for a total of 264 cycles, median 4 cycles per patient (range, 1-42). Twenty-eight (56%; 95% CI, 42.0-70.0%) of 50 patients achieved clinical benefit, with PFS and OS medians of 3.6 and 16.8 months, respectively.

CONCLUSIONS

Gemcitabine and topotecan are active agents in heavily pretreated, platinum- and paclitaxel-resistant EOC patients. Topotecan was more costly to deliver. Although a larger percentage of patients received clinical benefit with topotecan use, this likely reflects physician selection for use of topotecan earlier in the course of disease.

Treatment options for endometrial cancer: experience with topotecan

Although the prognosis for women with endometrial cancer confined to the uterus is relatively good, with a 5-year survival of approximately 90%, women with advanced or recurrent disease have a much poorer outcome. Systemic hormonal therapy with progestins improves survival in progesterone-receptor-positive tumors but chemotherapy is indicated as front-line therapy for most patients with this disease. Few single chemotherapy agents achieve response rates greater than 20%. The combination of doxorubicin and cisplatin is the first-line treatment of choice but the response and survival rates are still low compared to ovarian cancer treatments and more active regimens are needed. Treatment options for second-line chemotherapy are even more limited because of low response rates and toxicity issues related to prior radiation therapy. The topoisomerase I inhibitor, topotecan, is being investigated for the treatment of endometrial cancer. In previously treated patients, single-agent topotecan achieved a response in 10% of patients and disease stabilized in 55% of patients. The combination of topotecan and cisplatin is being studied in chemotherapy-naive elderly patients. Topotecan is also active in uterine papillary serous carcinoma, an aggressive form of the disease that generally does not respond to chemotherapy.

Optimal sequencing in the treatment of recurrent ovarian cancer

Improvements in ovarian cancer management mean that it may now be a long-term disease for which treatment must be carefully considered. Optimal sequencing of chemotherapy may help to enhance patients' benefit of therapy and minimize toxicity. The response to retreatment with platinum or a platinum/taxane combination is strongly influenced by the treatment-free interval after initial therapy with a platinum combination. Response rates to platinum retreatment in platinum-resistant patients (relapse within 6 months) are lower than those in platinum-sensitive patients (relapse after 6 months). Increasing the platinum-free interval by using non-platinum-based chemotherapy for treatment after relapse appears to increase the likelihood of response to later rechallenge with platinum. Many alternative agents have been investigated for the treatment of patients with relapsed ovarian cancer, including single-agent topotecan, which has been shown to achieve favorable responses. Topotecan may cause myelosuppression, which is noncumulative but tends to increase in direct correlation with the number of prior chemotherapy courses. Therefore, the best use of topotecan may be early in the course of salvage therapy. The hematologic toxicities associated with topotecan can also be reduced by adjusting the dose and schedule. Prolonged use of topotecan may be feasible and potentially beneficial in some patients.

The role of topotecan in the treatment of advanced cervical cancer

Improvements in the early detection of cervical cancer have markedly reduced associated mortality rates over the past few decades; however, in patients diagnosed with cervical cancer the rates have remained unchanged for 25 years. Hysterectomy, alone or with radiotherapy, is effective in early-stage disease, with a high cure rate, but the treatment of advanced and recurrent cervical cancer (usually with radiotherapy and cisplatin) is suboptimal, with 5-year survival rates of 50.9 and 16.5% for patients with regional involvement or distant disease, respectively. There is therefore an unmet need for more effective treatments for patients with advanced disease, and a number of new chemotherapy agents and treatment strategies have been investigated in this setting. Promising results have been reported in phase II trials of the topoisomerase inhibitor I, topotecan. Response rates of up to 19% have been reported in patients treated with topotecan as a single agent and response rates of up to 54% have been achieved when this agent is used in combination chemotherapy regimens. Toxicity levels are similar to those observed in patients with relapsed ovarian cancer and are not significantly different from levels with other chemotherapy agents. This paper reviews the current management of advanced cervical cancer and summarizes the available data on the use of topotecan in this setting.

Clinical experience with topotecan in relapsed ovarian cancer

Topotecan is an established therapy for the treatment of recurrent ovarian cancer and has demonstrated significant antitumor activity in both platinum-sensitive and platinum-resistant patient populations. The main toxicity associated with topotecan when used in the standard 5-day dosing schedule is myelosuppression, which is generally predictable, reversible, noncumulative, and manageable. Comparative trials have shown that topotecan is as effective as paclitaxel and pegylated liposomal doxorubicin in achieving tumor response, disease stabilization, and improved overall survival. Follow-up data extending to 4 years indicate that the survival benefit persists in long-term therapy without cumulative toxic effects. There appears to be little cross-resistance between topotecan and paclitaxel, indicating that the use of concurrent or sequential combination therapy could be a valuable option. Encouraging preliminary data suggest that alternative dosing schedules may improve the therapeutic index of topotecan and that topotecan may also be active as first-line therapy in combination with taxanes and/or platinum agents. Optimization of the use of topotecan may offer potential opportunities for further improving the management of ovarian cancer.