Continuous infusional topotecan in advanced breast and non-small-cell lung cancer: no evidence of increased efficacy

Plant-based natural products in cancer therapeutics

Various cells in our body regularly divide to replace old cells and dead cells. For a living cell to be growing, cell division and differentiation is highly essential. Cancer is characterised by uncontrollable cell division and invasion of other tissues due to dysregulation in the cell cycle. An accumulation of genetic changes or mutations develops through different physical (UV and other radiations), chemical (chewing and smoking of tobacco, chemical pollutants/mutagens), biological (viruses) and hereditary factors that can lead to cancer. Now, cancer is considered as a major death-causing factor worldwide. Due to advancements in technology, treatment like chemotherapy, radiation therapy, bone marrow transplant, immunotherapy, hormone therapy and many more in the rows. Although, it also has some side effects like fatigue, hair fall, anaemia, nausea and vomiting, constipation. Modern improved drug therapies come with severe side effects. There is need for safer, more effective, low-cost treatment with lesser side-effects. Biologically active natural products derived from plants are the emerging strategy to deal with cancer proliferation. Moreover, they possess anti-carcinogenic, anti-proliferative and anti-mutagenic properties with reduced side effects. They also detoxify and remove reactive substances formed by carcinogenic agents. In this article, we discuss different plant-based products and their mechanism of action against cancer.

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

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Activity of topotecan given intravenously for 5 days every three weeks in patients with advanced non-small cell lung cancer pretreated with platinum and taxanes: a phase II study

Topotecan, a semi-synthetic camptothecin analogue with topoisomerase I interaction, has shown to be an active agent in the treatment of advanced refractory lung cancer. This paper describes the authors' experience with this drug when used as a single agent in patients (pts) with advanced non-small cell lung cancer (NSCLC) refractory to platinum- and taxane-containing chemotherapy regimens. Thirty-five patients with NSCLC refractory to previous chemotherapy and KI ≥ 60% were included in the study. Their characteristics are as follows: median age of 52 years (range 43-69) and Karnofsky PS of 70 (60-80); 27 were male and 8 were female. Twenty-one (60%) patients had adenocarcinoma; eleven (31.4%), squamous cell, and three (8.5%), undifferentiated carcinoma. There was a median of two disease sites and two prior chemotherapy regimens. Topotecan was administered at a dose of 1.25 mg/m(2) I.V. daily for 5 days, repeated every 21 days until disease progression, maximal response, or intolerable toxicity. After 73 cycles, patients received a median of 2 treatment cycles (1-9). All patients except one were considered evaluable for toxicity; eight episodes (24%) of nausea/vomiting and two episodes (6%) of grade 1-2 asthenia, respectively, were reported. Four (12%) patients developed grade 1-2 anemia and two (6%) subjects suffered grade 3 anemia. Seven (21%) patients had grade 1-2 neutropenia and one (3%) presented grade 5 neutropenia. In 33 patients evaluable for activity of the 35 subjects included in the study; one (2.8%) presented a partial response; nine (25.7%) had stable disease, and 23 (65.7%) exhibited disease progression. Median time to progression and overall survival were 54 (12-210) and 70 (12-324) days, respectively. Intravenous topotecan at that dose and administration schedule displays scant activity in terms of response rate in individuals with advanced NSCLC previously treated with platinum and taxanes. The role and usefulness of chemotherapy in this setting warrants further investigation and confirmation through comparative studies.

A review of topotecan in combination chemotherapy for advanced cervical cancer

Treatment of advanced, recurrent or persistent cervical cancer includes radiotherapy and chemotherapy. Radiation has been the primary treatment modality for locoregionally advanced cervical cancer. Concomitant systemic cisplatin chemotherapy and radiation have shown high response rates with improvements in durable remissions and overall survival. Cisplatin has been the standard medication for the treatment of advanced cervical cancer. Combinations with other chemotherapeutic agents have been the subject of clinical trials with varying results. The toxicity of combination chemotherapy and tolerability of patients are other factors that should be considered in the management of patients with advanced disease. Recently topotecan, in combination with cisplatin, achieved increased response and overall survival rates without further compromising the patients' quality of life. This review focuses on the mechanism of action and toxicities of topotecan, as well as its role as a radio-sensitizer and chemotherapeutic agent in the management of advanced, recurrent, or persistent cervical cancer. Other combination modalities and dosages are also discussed.

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

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

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.

Single-agent chemotherapy for non-small cell lung cancer

The survival and quality of life benefits of combination chemotherapy in patients with non-small cell lung cancer (NSCLC) are now well recognized. Since many clinical trials have been conducted in relatively young patients with good performance status, many elderly patients and patients with poor performance status are not offered chemotherapy because of concerns about higher risks of toxicity. The newer agents, including topotecan, are active as single agents in NSCLC, achieving response rates of up to 30%. Overall survival and symptoms may be improved when these agents are added to best supportive care. They are well tolerated in both elderly patients and patients with poor performance status. The major toxicity with the standard 5-day administration schedule of topotecan is myelosuppression, but weekly schedules may offer reduced toxicity while maintaining efficacy. Thus, single-agent therapy with newer agents is generally considered in elderly and poor performance status patients. However, combination chemotherapy may also be appropriate for some patients in these subgroups. Future studies of chemotherapy in NSCLC should not exclude elderly patients and patients with poor performance status.

The camptothecins

Supported by detailed understanding of their mechanism of action, and facilitated by chemical manipulations that have amplified their solubility, the camptothecins have advanced to the forefront of several areas of therapeutic and developmental chemotherapy. Additive and synergistic laboratory interactions with other cytotoxic drugs have been exploited to allow development of camptothecin-based multidrug regimens, which are showing important activity in several malignancies. Topotecan and irinotecan are already in widespread use in clinical practice, and newer agents with promising preclinical activity are in various stages of clinical assessment. As knowledge of molecular and biochemical mechanisms of action and resistance continues to expand, newer and better camptothecin-based strategies for treatment of malignant disease are likely to evolve.

Modulation of camptothecin analogs in the treatment of cancer: a review

The topoisomerase I inhibitors reviewed in this paper are all semisynthetic analogs of camptothecin (CPT). Modulation of this intranuclear enzyme translates clinically in to antitumor activity against a broad spectrum of tumors and is therefore the subject of numerous investigations. We present preclinical and clinical data on CPT analogs that are already being used in clinical practice [i.e. topotecan and irinotecan (CPT-11)] or are currently in clinical development (e.g. 9-aminocamptothecin, 9-nitrocamptotecin, lurtotecan, DX 8951f and BN 80915), as well as drugs that are still only developed in a preclinical setting (silatecans, polymer-bound derivates). A variety of different strategies is being used to modulate the systemic delivery of this class of agents, frequently in order to increase antitumor activity and/or reduce experienced side effects. Three principal approaches are discussed, including: (i) pharmaceutical modulation of formulation vehicles, structural alterations and the search for more water-soluble prodrugs, (ii) modulation of routes of administration and considerations on infusion duration, and (iii) both pharmacodynamic and pharmacokinetic biomodulation.

New horizons in treating metastatic disease

The management of metastatic breast cancer is changing as a consequence of extraordinary discoveries in cancer research and the development of more advanced diagnostic technologies. Although traditional chemotherapeutics such as anthracyclines and taxanes still represent the mainstay of treatment for this disease, new drugs are demonstrating significant clinical activity and sometimes a better toxicity profile. Furthermore, the successful introduction into clinical practice of biological agents, in particular the monoclonal antibody trastuzumab, offers a key to the future of managing metastatic breast cancer. A therapeutic approach based on modifications of a specific molecular target (e.g., gene therapy, vaccines, and antiangiogenesis) alone or combined with the traditional chemotherapeutic drugs is expected to be used more commonly and will, we hope, bring significant improvement in the clinical response and quality of care of our patients.

Topotecan in squamous cell carcinoma of the cervix: A Phase II study of the Gynecologic Oncology Group

PURPOSE

The activity and toxicity of topotecan were evaluated in a multicenter Phase II study for patients with previously treated squamous cell carcinoma of the uterine cervix.

PATIENTS AND METHODS

Histologic confirmation of the primary diagnosis was required, as well as adequate performance status and vital organ function and the presence of measurable disease. Patients were allowed one prior regimen of systemic therapy, usually platinum-based. A two-stage accrual design was utilized with early stopping criteria and monitoring of toxicity. Topotecan was administered at 1.5 mg/m(2) per day for 5 consecutive days on a 21-day cycle with modifications based on hematologic toxicity.

RESULTS

Forty-five patients were entered. Two patients were ineligible (incorrect tumor type) and 2 were inevaluable (never received therapy). One additional patient was not evaluable for response (nonmeasurable disease). A median of 2 cycles was administered to each patient (range: 1-17 cycles) with grade 4 neutropenia in 68% and grade 4 thrombocytopenia in 39% of patients, but without treatment-related deaths. Nonhematologic toxicity was generally mild and not dose-limiting. The overall (complete and partial) response rate among evaluable patients with measurable disease was 12.5% with stable disease in an additional 37. 5%. Median progression-free survival was 2.1 months.

CONCLUSIONS

As a single agent topotecan shows modest antitumor activity, with manageable hematologic and nonhematologic toxicity, in patients with previously treated squamous cell carcinoma of the cervix. Further evaluation in chemotherapy-naive patients or in combination with cisplatin and/or radiation may be indicated.

Phase I/pharmacokinetic study of the topoisomerase I inhibitor GG211 administered as a 21-day continuous infusion

BACKGROUND

Preclinical results support a prolonged schedule of administration for topoisomerase I inhibitors, and we have previously demonstrated the safety and activity of the novel water-soluble topoisomerase I inhibitor GG211 when given as a 72-hour continuous infusion to cancer patients.

PATIENTS AND METHODS

In a three-center international phase I trial, 38 patients received GG211 doses from 0.3 to 0.5 mg/m2/day by continuous intravenous infusions for seven, 14, and 21 days. Patients' median performance status was 1; nearly half had colorectal cancer, and 35 patients had prior chemotherapy.

RESULTS

The first patient cohort received 0.3 mg/m2/day for seven days with no significant toxicities. Subsequent cohorts received continuous infusions for 14 and 21 days at this dose level with only mild myelosuppression noted. Dose-escalation on the 21-day schedule was then performed. No dose-limiting toxicity occurred at the 0.4 mg/m2/day dose level. Thrombocytopenia was dose-limiting with 0.5 mg/m2/day dosing but was not cumulative. Other grade 3 4 toxicities included neutropenia, nausea, vomiting, diarrhea, and fatigue. Partial responses occurred with 21-day infusion in two patients with breast and ovarian cancer at the 0.3 and 0.4 mg/m2/day dose levels, respectively. Mean GG211 lactone Css ranged from 0.17 to 0.64 ng/ml.

CONCLUSION

The maximum tolerated dose of GG211 administered as a 21-day continuous infusion is 0.4 mg/m2/day with antitumor activity noted at tolerable doses.

Drug resistance in lung cancer

The major problem in lung cancer chemotherapy is the emergence of inherent and acquired drug resistance of the cancer cells. Establishment of drug-resistant sublines and comparative investigations of such cell lines with their parental cells to determine their molecular, biologic, and biochemical properties are important research strategies. Genetic changes in tumor cells may induce changes in their biochemical properties and chemosensitivity. Many mechanisms that render tumor cells resistant have been identified, and they have provided new molecular targets for surrogate markers to predict chemosensitivity. The new categories of anticancer drugs, such as topoisomerase I inhibitors and taxanes, and non-cytotoxic new drugs, have been introduced clinically. It is important to define the molecular determinants of resistance to these drugs. The development of an appropriate model for overcoming drug resistance is one of the important issues that should be solved before carrying out further clinical trials.

Clinical benefit from palliative chemotherapy in non-small-cell lung cancer extends to the elderly and those with poor prognostic factors

The intention of this study was to identify the pretreatment characteristics predicting for the survival, objective response and symptom relief in patients with non-resectable, non-small-cell lung cancer (NSCLC) managed in the Lung Unit at the Royal Marsden Hospital. This analysis included 290 patients with advanced NSCLC generally treated with a cisplatin-based chemotherapy regimen in one of a series of trials. Thirty-seven pretreatment variables, response and survival data were collected prospectively and analysed using univariate and multivariate methods. By multivariate analysis performance status, disease extent and pattern of metastases along with certain biochemical features were influential independent variables for survival, objective and symptom response. Older age was positively associated with objective response (P = 0.04). When the independent factors for symptom response were used to group patients into prognostic categories, 30-48% of patients with an adverse set of factors had symptom relief. Similarly using the relative risk of death to subgroup the patient population, 54% of patients at high risk of death (greater than 8.0), with a median survival of 2.5 months, had symptom relief. The data are consistent with other studies in identifying the pretreatment factors predicting for survival and objective response. Additionally, older age is positively associated with objective response and the majority of patients with the worst prognosis have symptom relief from treatment with chemotherapy.