Treatment of poor-prognosis extensive disease small-cell lung cancer with an all-oral regimen of etoposide and cyclophosphamide - a Southwest Oncology Group clinical and pharmacokinetic study

Clinico-Pathological Correlation of β-Catenin and Telomere Dysfunction in Head and Neck Squamous Cell Carcinoma Patients

BACKGROUND

Tumorigenesis is a complex process of accumulated alteration in function of multiple genes and pathways. Wnt signalling pathway is involved in various differentiation events during embryonic development and is conserved in various species.

OBJECTIVE

A multicentre collaborative initiative is undertaken to study the occurrence, prognosis and molecular mechanism of HNSCC (Head and Neck Squamous Cell Carcinoma) which is highly prevalent in eastern parts of India. From a large cohort of HNSCC tissue repository, 67 cases were selected for multi-parametric investigation.

RESULTS

67 cases showed stable β-catenin expression. We have seen correlation, if any, of the transcription factor - β-catenin, telomere maintenance and shelterin complex proteins - TRF2, Rap1 and hTert with respect to tumor differentiation and telomere dysfunction. Immunohistochemistry of β-catenin protein showed stable and high expression in tumor when compared to stroma. MDSCC (Moderately Differentiated Squamous cell carcinoma) cases expressed nuclear expression of β-catenin in invasive fronts and showed increased genomic instability. Higher frequency of Anaphase bridges was observed ranging from <3% in normal cut margin to 13% in WDSCC (Well differentiated squamous cell carcinoma) and 18% in MDSCC (Moderately differentiated Squamous cell carcinoma). There was significant decrease in telomere length in MDSCC (<4) when compared to the normal cut margin samples (<7). Quantitative Real Time-PCR confirmed a significant correlationship between stable β-catenin expression and poor clinical and pathological outcome.

CONCLUSION

The Stabilisation and accumulation of β-catenin was significant and correlated well with de-differentiation process as well as prognosis and therapy outcome of the patients in the cohort. Expression status of molecular markers such as β-catenin, hTert, TRF2 and RAP1 correlate significantly with the process of tumorigenesis and prognosis and may play a role in therapeutic management of Head and neck patients.

Phase II study of oral etoposide maintenance for patients with extensive stage small cell lung cancer who have responded to the induction on an EP regimen

BACKGROUND

Maintenance therapy for extensive stage small cell lung cancer (ES-SCLC) is still under debate. Many new agents fail during the maintenance course. As an active agent for SCLC, oral etoposide is worth being re-evaluated.

METHODS

This phase II study was performed to evaluate the toxicity/efficacy of the maintenance of patients with oral etoposide with ES-SCLC responding (complete remission [CR] + partial remission [PR]) to the induction of four cycles of etoposide plus cisplatin (EP) chemotherapy. Maintenance therapy with oral etoposide (50 mg/m² , day 1-14, repeated every 21 days until disease progression or unacceptable toxicity occurs) was administered. The primary endpoints were grade 3 and 4 toxicities and progression free survival (PFS).

RESULTS

Fifty-four patients with ES-SCLC received standard EP regimens as induction therapy; 31 responding patients were administered oral etoposide as the maintenance treatment. The most common hematological and non-hematological toxicity of the maintenance course was neutropenia and fatigue, respectively. Median PFS was nine months (95% confidence interval (CI): 8.33∼9.67 months), median overall survival (OS) was 14 months (95% CI: 11.58∼16.42 months). Significantly better PFS and OS were seen in patients responding to the induction EP chemotherapy.

CONCLUSIONS

Oral etoposide maintenance is safe and effective for patients with ES-SCLC who responded to the induction of EP chemotherapy. Significant survival benefit was revealed in patients completely responding to an EP regimen. Further randomized control study is warranted.

Extensive disease small cell lung cancer dose-response relationships: implications for resistance mechanisms

BACKGROUND

Some studies (but not others) suggested that high doses are beneficial in small cell lung cancer (SCLC). We hypothesized that dose-response curve (DRC) shape reflects resistance mechanisms.

METHODS

We reviewed published SCLC clinical trials and converted response rates into estimated mean tumor cell kill, assuming killing is proportional to reduction in tumor volume. Mean % cell survival was plotted versus planned dose intensity. Nonlinear and linear meta-regression analyses (weighted according to the number of patients in each study) were used to assess DRC characteristics.

RESULTS

Although associations between dose and cell survival were not statistically significant, DRCs sloped downward for five of seven agents across all doses and for all seven when lowest doses were excluded. Maximum mean cell kill across all drugs and doses was approximately 90%, suggesting that there may be a maximum achievable tumor cell kill irrespective of number of agents or drug doses.

CONCLUSIONS

Downward DRC slopes suggest that maintaining relatively high doses may possibly maximize palliation, although the associations between dose and slope did not achieve statistical significance, and slopes for most drugs tended to be shallow. DRC flattening at higher doses would preclude cure and would suggest that "saturable passive resistance" (deficiency of factors required for cell killing) limits maximum achievable cell kill. An example of factors that could flatten the DRC at higher doses and lead to saturable passive resistance would be presence of quiescent, noncycling cells.

[Randomised phase II study evaluating oral combination chemotherapy (CCNU, cyclophosphamide, etoposide) and intravenous chemotherapy as second-line treatment for relapsed small cell bronchial carcinoma (Trial GFPC0501)]

BACKGROUND

There is no standard second-line treatment for small cell lung cancer (SCLC). The prognosis of these patients is poor and special attention should be paid to both quality of life and economic factors.

METHODS

The aim of this phase II randomised trial (GFPC0501) is to compare, in patients with progressive SCLC after first-line platinum based chemotherapy, oral multi drug chemotherapy (CCNU, cyclophosphamide, etoposide) and classical intravenous chemotherapy with cyclophosphamide, doxorubicin and vincristine (CAV) in terms of tolerability, efficacy (response rate, median one year survival and overall survival), quality of life and consumption of health care resources. Based on a two-stage Bryant and Day approach, this study will require a total of 138 patients with an interim analysis of the first 38.

EXPECTED RESULTS

This trial will provide information on several aspects of second-line chemotherapy for patients with SCLC. Thirty six patients have been enrolled in 16 centres by December 2006 and the results of the interim analysis will be available in June 2007.

Topotecan therapy in patients with relapsed small-cell lung cancer and poor performance status

PURPOSE

Topotecan is generally well tolerated and active in patients with relapsed small-cell lung cancer (SCLC) and poor performance status (PS). In this study, we investigated whether treatment with topotecan is associated with improvement in PS as measured by the rate of conversion from PS 2 to PS 0/1.

PATIENTS AND METHODS

A retrospective analysis of data from 7 clinical trials (N = 795) investigating topotecan in patients with relapsed SCLC was performed. All patients received topotecan 1.25-1.5 mg/m2 daily on days 1-5 of a 21-day cycle. Demographics were similar for patients with PS 2 and PS 0/1. A total of 152 patients with PS 2 at baseline received 502 cycles (median, 2 cycles; range, 1-14 cycles) of therapy, and 32 (21%) experienced PS improvement to PS 0/1 that lasted for > or = 2 cycles.

RESULTS

Overall, 50% of patients who experienced PS conversion also exhibited an objective antitumor response, compared with 8% of patients with PS 2 who had no improvement in PS and achieved a response. Similarly, median overall survival was longer for patients with PS improvement (37 weeks; 95% confidence interval, 29.6-49.4 weeks) compared with patients with PS 2 who had a response but no PS improvement (10.4 weeks; 95% confidence interval, 8.7-13.6 weeks). A substantial proportion of patients with PS 2 and relapsed SCLC experienced PS improvement during topotecan treatment. These patients had a substantially longer median survival and a higher response rate compared with the overall trial population.

CONCLUSION

Improvement in PS appears to be a good indicator of benefit from topotecan therapy.

Pharmacokinetic Optimisation of Treatment with Oral Etoposide

Etoposide is a derivative of podophyllotoxin widely used in the treatment of several neoplasms, including small cell lung cancer, germ cell tumours and non-Hodgkin's lymphomas. Prolonged administration of etoposide aims for continuous inhibition of topoisomerase II, the intracellular target of etoposide, thus preventing tumour cells from repairing DNA breaks. However, the clinical advantages of extended schedules as compared with conventional short-term infusions remain unclear. Oral administration of etoposide represents the most feasible and economic strategy to maintain effective concentrations of drug for extended times. Nevertheless, the efficacy of oral etoposide therapy is contingent on circumventing pharmacokinetic limitations, mainly low and variable bioavailability. Inhibition of small bowel and hepatic metabolism of etoposide with specific cytochrome P450 inhibitors or inhibition of the intestinal P-glycoprotein efflux pump have been attempted to increase the bioavailability of oral etoposide, but the best results were obtained with daily oral administration of low etoposide doses (50-100 mg/day for 14-21 days). Saturable absorption of etoposide was reported for doses greater than 200 mg/day, whereas lower doses were associated with increased bioavailability, although they were characterised by high inter- and intrapatient variability. Pharmacokinetic parameters such as plasma trough concentration between two oral administrations (C(24,trough)), drug exposure time above a threshold value and area under the plasma concentration-time curve have been correlated with the pharmacodynamic effect of oral etoposide. Pharmacokinetic-pharmacodynamic relationships indicate that severe toxicity is avoided when peak plasma concentrations do not exceed 3-5 mg/L and C(24,trough) is under the threshold limit of 0.3 mg/L. To maintain effective etoposide plasma concentrations during prolonged oral administration, pharmacokinetic variability must be monitored in each patient, taking account of factors from many pharmacokinetic studies of etoposide, including absorption, distribution, protein binding, metabolism and elimination. Dosage reduction is generally useful to avoid haematological toxicity in patients with renal dysfunction (creatinine clearance <50 mL/min). The need for dosage adjustment based on liver function in patients with liver dysfunction is not completely defined, but generally is not indicated in patients with minor liver dysfunction. Adaptive dosage adjustment based on individual pharmacokinetic parameters, estimated using limited sampling strategies and population pharmacokinetic models, is more appropriate. This approach has been used with success in different clinical trials to increase the etoposide dosage, without significantly increasing toxicity. Various pharmacodynamic models have been proposed to guide etoposide oral dosage. However, they lack precision and accuracy and need to be refined by considering other predictor variables in order to extend their application in current clinical practice.

Gemcitabine plus etoposide in chemonaive extensive disease small-cell lung cancer: a multi-centre phase II study

BACKGROUND

Both gemcitabine and etoposide are active in the treatment of small-cell lung cancer (SCLC), and are characterised by mild toxicity profiles. The combination of both drugs was found to be feasible and active in a phase I dose-finding study in solid tumours. Therefore, a phase II trial was initiated to examine the activity and toxicity of this schedule in extensive disease SCLC.

PATIENTS AND METHODS

Forty-two chemo-naïve extensive disease SCLC patients were enrolled to receive gemcitabine 1000 mg/m2, days 1, 8 and 15, and etoposide 80 mg/m2, days 8, 9 and 10 of a 28-day cycle.

RESULTS

Thirty-seven patients were evaluable for efficacy (five received less than one cycle). No complete responses were observed, but partial responses were seen in 17 patients, yielding an overall response rate of 46%. The median duration of response was 5.8 months. Disease stabilisation was obtained in another 10 patients (27%). The median survival of the 37 protocol-qualified patients was 10.5 months (95% confidence interval (CI): 7.5-12.0). The levels of WHO grade 3 and 4 toxicities were low and clinically manageable.

CONCLUSION

In comparison with standard platinum-based regimens, this combination of gemcitabine and etoposide resulted in a somewhat lower response rate, but a similar median survival time. Haematological toxicity was more pronounced than expected from the toxicity data of each agent individually. However, because of its mild non-haematological toxicity, and its ability to be administered in an outpatient setting, this combination provides a reasonable palliative option for patients with extensive disease SCLC.