A dose-escalation study of weekly topotecan, cisplatin, and gemcitabine front-line therapy in patients with inoperable non-small cell lung 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.

Simplified gemcitabine and platin regimen in patients with advanced or metastatic non-small cell lung cancer (NSCLC) to be proposed as neoadjuvant therapy

BACKGROUND

Chemotherapy of non-small-cell lung cancer (NSCLC) has been improved by the use of cis-platin (P) and the pyrimidine antimetabolite gemcitabine (G) (2',2'-difluorodeoxycytidine). GP regimens currently used in Italy for NSCLC were and are mainly based on G day 1, 8 and 15; P on day 2, every 28 days (4 Day-Hospital admissions per cycle). However, the third G dose is frequently omitted because of myelo-toxicity, with a consistent dose decrease of both G and P in comparison with the intended dose. The 24-h lag time from 1(st) G and P has not reasonable clinical pharmacology base.

AIM OF THE STUDY

To have a simplified GP regimen based on two Day-Hospital admissions per cycle, with G on day 1 and 8, P after G on day 8; every 21 days, with the goal to use it in the neoadjuvant setting.

MATERIAL AND METHODS

The study was designed as a controlled, prospective, multicentre investigation, based on G (1500 mg/m(2)) on day 1 and 8, and P (100 mg/m(2)) on day 8 immediately following G, administered on a 3-week cycle. Quality of life (EORTC) was valuated in 46 patients out of 95 valuable patients. Restaging procedures were repeated after the 3rd and the 6th cycle.

RESULTS

Enrolled patients were 105 (stage IV: 63: IIIB: 29; IIIA: 13). GP cycles were 488 (1 to 6 per patient) 95 patients had at least 3 cycles and 59 of them had further 3 cycles. Myelotoxicity >or= g3 was mainly neutropenia, easily amenable with symptomatic and GCSF therapies (12.6% neutropenic fever); PNS toxicity occurred in 17.9% of patients. QoL was ameliorated (P < 0.05). Therapy was tolerable and gave a Response Rate (RR) of 52.3% after 3 cycles (Intention-to-treat analysis) and of 57.9% in 95 valuable patients who received at least 3 therapy cycles.

CONCLUSION

Present results confirm a good efficacy and/or synergism of G to P, with G on day 1 and 8 and P on day 8. This two day-hospital admissions regimen is at least as good as more complex GP regimens, and may be proposed in the neoadjuvant 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.

Weekly topotecan in heavily pretreated patients with recurrent epithelial ovarian carcinoma

OBJECTIVE

To investigate weekly topotecan in heavily pretreated patients with recurrent ovarian cancer.

METHODS

The records of patients with recurrent epithelial ovarian cancer who were treated with weekly topotecan after failure of > or =1 prior regimen were reviewed. Patients received topotecan (median starting dose approximately 2.5 mg/m(2)) on days 1, 8, and 15 of a 28-day cycle. Antitumor response was assessed after 2 cycles by serial CA-125 levels.

RESULTS

Thirty-five heavily pretreated patients received a mean of 5 cycles of topotecan (range, 1-13 cycles). Thirty-two patients had definable platinum sensitivity (16 sensitive, 8 resistant, 8 refractory). Median age was 56 years. A total of 177 cycles (534 weeks) of topotecan was administered. Hematologic toxicity was generally mild, and no grade 4 toxicities were observed. Grade 3 hematologic toxicity, including leukopenia, neutropenia, thrombocytopenia, and anemia, was observed in 2, 2, 1, and 0 patients, respectively. No patients experienced grade 3 or 4 nonhematologic toxicity. Based on serial CA-125 measurements, there were 1 (3%) complete and 5 (15%) partial responses, with 1 of the partial responses in a patient with platinum-refractory disease. Stable disease was reported in 13 (38%) patients, including 5 patients with platinum-resistant/refractory disease.

CONCLUSION

Weekly topotecan demonstrates activity and is well tolerated compared with historical data with the standard 5-day schedule. Higher doses may be warranted because of the high tolerability shown for weekly topotecan. Weekly topotecan may be an appropriate treatment option for patients with recurrent ovarian cancer, especially heavily pretreated patients who might require dosing schedules with improved tolerability.

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.

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.