Phase I study of paclitaxel and topotecan for the first-line treatment of extensive-stage small cell lung cancer

A novel oral camptothecin analog, gimatecan, exhibits superior antitumor efficacy than irinotecan toward esophageal squamous cell carcinoma in vitro and in vivo

Esophageal squamous cell carcinoma (ESCC) is a frequently diagnosed and deadly malignancy with few standard therapeutic options. Camptothecins are considered one of the most promising antitumor drugs. A modified lipophilic analog, gimatecan, was synthesized as a novel oral camptothecin and showed impressive effects in various tumors, but its therapeutic efficacy and mechanisms in ESCC remain unclear. This study investigated the antitumor efficacy and mechanisms of gimatecan in ECSS both in vitro and in vivo. Using ESCC cell lines, cell line-derived xenografts and patient-derived xenografts models, we evaluated gimatecan’s inhibition of tumor growth, and compared its antitumor efficacy with that of irinotecan. Topoisomerase I function and expression were assessed using the DNA relaxation assay and Western blotting, respectively. DNA damage was evaluated by Western blotting. Cell cycle progression and cell apoptosis were assessed using flow cytometry and Western blotting. Gimatecan could significantly suppress tumor growth in vivo and inhibit tumor cell proliferation in vitro, which was superior to irinotecan. Gimatecan suppressed the function and expression of topoisomerase I. It also caused DNA damage and activated the phosphorylation of multiple checkpoint gatekeepers, such as ATM, ATR, BRCA1, H2AX, CHK1, CHK2, and p53. It induced S phase arrest, enhanced the expression of p21^WAF1/CIP, and suppressed the expression of CDK2 and cyclin A. Induction of apoptosis was accompanied by increases in Bax, cleaved-caspase 3 activation, cleaved-caspase 9 induction, and a decrease in Bcl-2. The molecular and phenotypic changes induced by gimatecan were stronger than that of irinotecan. In ESCC, gimatecan suppressed the expression and function of topoisomerase I, induced DNA damage and intra-S phase cell cycle arrest, and resulted in apoptosis. And the results suggest that gimatecan has higher potency in inhibiting ESCC tumor growth than irinotecan, providing a rational novel therapeutic strategy for future clinical evaluation.

Chemotherapy in the treatment of metastatic, persistent, and recurrent cervical cancer

PURPOSE OF REVIEW

Patients with cervical cancer represent a vulnerable population with limited chemotherapeutic options. This year, two large trials focusing on detection/screening and treatment of advanced stage cervical cancer were featured in the opening plenary session of the American Society of Clinical Oncology Annual Meeting. As such, a review of the evolution of chemotherapy in the treatment of this disease is warranted.

RECENT FINDINGS

Following the establishment of cisplatin as an effective single-agent regimen in patients with advanced stage, recurrent, or persistent cervical cancer, several platinum-containing combinations were studied. Ultimately, the adoption of cisplatin chemosensitizing radiation resulted in relative 'cisplatin resistance' and the concept of nonplatinum doublets emerged as an active area of investigation.

SUMMARY

In an era of biologics, combined therapy with cytotoxic drugs and molecular targeted agents, as well as the use of nonplatinum doublets, represent an exciting area yet to be fully explored.

Development and validation of the HPLC method for simultaneous estimation of Paclitaxel and topotecan

A simple, rapid, accurate and precise high performance liquid chromatography (HPLC) method for simultaneous analysis of Paclitaxel and Topotecan was developed. Different analytical parameters, such as linearity, accuracy, precision, specificity with intentional degradation, limit of detection and limit of quantification (LOQ), were determined according to the ICH guidelines. Acetonitrile-water (70:30, 0.1% trifluoroacetic acid) was run on a Phenomenex Luna C-18(2) column in isocratic mode at a flow rate of 1.2 mL/min for simultaneous analysis of the two drugs using a UV detector set at 227 nm. The proposed method showed a retention time (Rt) of 14.56 min for Topotecan and 23.81 min for Paclitaxel with a continuous run up to 30 min. The linearity of the calibration curves for each analyte in the desired concentration range was found to be good (r(2) > 0.9995). The recovery ranged from 97.9 to 101% for each drug with a relative standard deviation (%RSD) of <2%. Peaks corresponding to each of the drugs exhibited  positive values for the minimum peak purity index over the entire range of integrated chromatographic peak indicating high purity of the peaks. Stability analysis revealed that the drugs remained stable for sufficient time. Thus, the developed method was found to be robust and it can be employed to quantify Paclitaxel and Topotecan in commercial sample and rat blood/serum.

Recent achievements and future developments in advanced and recurrent cervical cancer: trials of the Gynecologic Oncology Group

Following publication of five pivotal randomized trials of concurrent chemo-irradiation for patients with locally advanced cervical cancer (ie, International Federation of Gynecology and Oncology (FIGO] stages IB2-IVA) in 1999 and 2000, the National Cancer Institute issued a Clinical Alert advising that concurrent chemotherapy (typically, single-agent cisplatin) be incorporated into the treatment program of women scheduled to receive definitive pelvic radiotherapy. Although the adoption of this new standard has improved overall survival and decreased the recurrence rate by 50%, for those patients who do relapse, the prognosis is very poor and, ultimately, therapy in this setting is palliative in nature. The Gynecologic Oncology Group (GOG) has now completed eight randomized trials for metastatic and recurrent cervical cancer, all of which have studied cisplatin-based regimens. The eighth trial (protocol 204) compared four cisplatin-based doublets containing paclitaxel, topotecan, vinorelbine, or gemcitabine. Because the vast majority of patients are now expected to receive cisplatin "up front" as part of primary therapy with pelvic radiation, there are concerns for the development of drug-resistant clones in recurrences both inside and outside of the radiation field. The GOG has recently reported the results from a phase II trial evaluating the anti-vascular agent, bevacizumab, in women who were eligible for second-line or third-line therapy for metastatic and/or recurrent disease (protocol 227C). It becomes imperative that we continue to evaluate novel regimens for this disease.

Topotecan in the first-line treatment of small cell lung cancer

Small cell lung cancer (SCLC) is generally sensitive to first-line chemotherapy, but limited disease often recurs and extensive disease is rarely curable. The most common first-line therapy regimen is cisplatin (Platinol; Bristol-Myers Squibb; Princeton, NJ) plus etoposide (Etopophos; Bristol-Myers Squibb)--PE, which is associated with overall response rates >80% in patients with limited SCLC. Although it is associated with median survival times of approximately 18-20 months for limited disease, PE yields median survival times of only approximately 8-12 months in patients with extensive disease, and symptom palliation becomes the primary therapeutic goal. The toxicities of PE may undermine quality of life and leave patients more susceptible to adverse events during subsequent therapies. Topotecan (HYCAMTIN; GlaxoSmithKline; Philadelphia, PA), an established treatment for recurrent SCLC, is being investigated in the first-line setting because of its novel mechanism of action; predictable, noncumulative, and manageable toxicities; and potential synergy with other active agents. Several recent phase II trials have generated promising results for topotecan-based combination regimens, including topotecan/paclitaxel (TAXOL; Bristol-Myers Squibb) (overall response rates 45%-100%), topotecan/etoposide (overall response, 95%), and topotecan, paclitaxel, and platinum agent triplets (overall response rates 51%-93%). The most frequent serious toxicity associated with these regimens was reversible and noncumulative neutropenia, which was generally manageable with supportive care. Additional clinical trials to investigate topotecan-based combination regimens and confirm their role in the first-line treatment of SCLC are under way.

A Phase II trial of paclitaxel and topotecan with filgrastim in patients with recurrent or refractory glioblastoma multiforme or anaplastic astrocytoma

PURPOSE

Therapy for high-grade gliomas remains unsatisfactory. Paclitaxel and topotecan have separately demonstrated activity against gliomas. We conducted a Phase II trial of these agents in combination with filgrastim (G-CSF) in patients with recurrent or refractory glioblastoma multiforme or anaplastic astrocytoma.

PATIENTS AND METHODS

Adult patients with radiographic evidence of recurrent or progressive tumor following primary therapy were eligible for study. Patients received paclitaxel 175 mg/m2 IV over 3 h on day 1 and topotecan 1.0 mg/m2 IV over 30 min on days 1-5. Filgrastim 5 microg/kg was given days 6-14 for neutrophil support. Treatment cycles were repeated every 21 days.

RESULTS

Twenty patients were enrolled on study, and seventeen were considered evaluable for response. Two patients (12/%) exhibited partial remission and seven patients (41/%) exhibited stable disease in response to therapy. Hematologic toxicity was common with 25 /% of patients experiencing grade III or IV leukopenia despite G-CSF support. Two patients died of infectious complications on protocol, prompting suspension of further accrual.

CONCLUSION

Paclitaxel and topotecan with G-CSF support exhibits modest activity in adults with recurrent or refractory glioblastoma and anaplastic astrocytoma. The significant hematotoxicity encountered, however, cannot justify further investigation of this combination in patients with high grade brain tumors.

Small cell lung cancer: state of the art and future perspectives

Small cell lung cancer accounts for less than 20% of all lung cancer. The management of this distinct tumor entity differs from the more common non-small cell lung cancer. Primary prevention of smoking exposure remains the most important public health measure. Although small cell lung is an exquisitely chemosensitive disease it remains ultimately fatal for the great majority of patients. Combination chemotherapy regimens have improved response rate and survival of the last three decades. The combination of cisplatin and etoposide has been considered the standard therapy for over a decade. More intensive triplet combination chemotherapy and high-dose chemotherapy have shown improved response rates and survival. Early concomitant and accelerated radiotherapy improves survival in limited stage disease. This review summarizes the current state of the art and future perspectives in detection, staging and standard therapy of small cell lung cancer. Particular emphasis is given to the importance of concomitant and accelerated radiotherapy and consideration of dose-intensive combination chemotherapy regimens.