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Journal of Clinical Oncology, Vol 24, No 34 (December 1), 2006: pp. 5441-5447 © 2006 American Society of Clinical Oncology. DOI: 10.1200/JCO.2006.06.5821 Phase III Trial Comparing Supportive Care Alone With Supportive Care With Oral Topotecan in Patients With Relapsed Small-Cell Lung Cancer
From the Royal Marsden Hospital, Sutton; Christie Hospital, Manchester; GlaxoSmithKline, Harlow, United Kingdom; Institutul Oncologic, Cluj-Napoca, Romania; Active Treatment Hospital, Varna, Bulgaria; Lviv State Oncology, Lviv, Ukraine; Klinika za plu Address reprint requests to Mary O'Brien, MD, FRCP, Royal Marsden Hospital, National Health System Trust, Sutton Surrey, SM2 5 PT, England; e-mail: mary.o'brien{at}rmh.nhs.uk
PURPOSE: For patients with small-cell lung cancer (SCLC), further chemotherapy is routinely considered at relapse after first-line therapy. However, proof of clinical benefit has not been documented. PATIENTS AND METHODS: This study randomly assigned patients with relapsed SCLC not considered as candidates for standard intravenous therapy to best supportive care (BSC) alone (n = 70) or oral topotecan (2.3 mg/m2/d, days 1 through 5, every 21 days) plus BSC (topotecan; n = 71).
RESULTS: In the intent-to-treat population, survival (primary end point) was prolonged in the topotecan group (log-rank P = .0104). Median survival with BSC was 13.9 weeks (95% CI, 11.1 to 18.6) and with topotecan, 25.9 weeks (95% CI, 18.3 to 31.6). Statistical significance for survival was maintained in a subgroup of patients with a short treatment-free interval ( CONCLUSION: Chemotherapy with oral topotecan is associated with prolongation of survival and quality of life benefit in patients with relapsed SCLC.
The majority of patients with small-cell lung cancer (SCLC) who are treated with standard chemotherapy experience relapse within 1 year of treatment. At relapse, patients are routinely considered for further chemotherapy, and there is evidence that this is associated with symptom improvement in patients who have a relatively long treatment-free interval (TFI) after first-line therapy (considered sensitive disease).1,2 Patients with short TFI (or resistant SCLC) are less likely to achieve objective tumor response than patients with sensitive SCLC,3 and for them the risks versus benefits of chemotherapy at relapse are ill defined. Topotecan (Hycamtin; GlaxoSmithKline, Research Triangle Park, NC) inhibits the cut-and-repair nuclear enzyme topoisomerase I. The intravenous formulation is active against relapsed ovarian cancer and SCLC.4-8 An oral formulation of topotecan has similar efficacy to the intravenous formulation in patients with relapsed SCLC.9-11 In a phase III study of patients with relapsed sensitive SCLC, response rates with oral and intravenous topotecan were 18.3% and 21.9%, respectively.11 In order to define the actual risk and benefit associated with chemotherapy at relapse with SCLC, a randomized study was conducted. Patients unsuitable for standard intravenous chemotherapy received either oral topotecan plus best supportive care (topotecan) or best supportive care alone (BSC) and were evaluated for survival, quality of life (QOL), and adverse experiences.
Patient Selection Patients were randomly assigned 1:1 using a centralized automated registration and randomization system (JhoyLink, Paris, France),12 stratified by sex, performance status (PS 0/1 or 2), TFI ( 60 days or > 60 days), and presence of liver metastases. Because of the possibility of being randomly assigned to BSC alone, only patients considered unsuitable for further intravenous chemotherapy were recruited. Unsuitability was based on local policy concerning the unproven risk and benefit in patients with resistant (short TFI) SCLC and assessed on an individual basis by the attending oncologist. Initially excluded from the protocol were patients who had a TFI of longer than 90 days for whom treatment with BSC alone was not acceptable. However, as the study progressed, it became apparent that some patients with sensitive SCLC refuse further chemotherapy because of the risk of toxicity or become unsuitable for standard chemotherapy because of comorbidities. The protocol was therefore amended to allow the inclusion of such patients. As the population was stratified at random assignment, the final study population is comprised of two predefined subsets according to TFI. A minimum of 45 days was required after initial chemotherapy to ensure bone marrow recovery.
Other eligibility criteria included extensive or limited SCLC, one prior chemotherapy regimen, age Exclusion criteria were symptomatic CNS metastases, concomitant or previous malignancies within the last 5 years (except SCLC and adequately treated nonmelanoma skin cancer, cervical carcinoma in situ, or localized low-grade prostate cancer), infection, severe comorbidities, gastrointestinal conditions or drugs affecting gastrointestinal absorption, prior topotecan therapy, or hypersensitivity or other contraindication to the study drugs. The protocol was approved by the institutional review board/ethics committee at each site, and each patient provided written informed consent.
Interventions
Dose Delays and Modifications
To ensure optimal topotecan exposure, individual dose adjustments were prescribed in the protocol. The topotecan dose was reduced by 0.4 mg/m2/d for neutrophils less than 500/mm3 associated with fever/infection or lasting
Assessments Patients on both study arms were evaluated at similar intervals: before each course of topotecan or approximately every 21 days for patients on the BSC arm. At each visit, the patient was interviewed and examined and completed the PSA and EQ-5D. PS was recorded and palliative measures documented. In the topotecan arm, toxicity (according to National Cancer Institute Common Toxicity Criteria) was evaluated and blood counts were obtained. During treatment, blood counts were obtained on day 8 and blood chemistries on day 15. Hematologic and biochemical toxicities were assessed from laboratory values; all other toxicities were from investigator-reported adverse events. Radiographic disease assessment was only required in the topotecan arm after three courses and thereafter only to confirm response or progressive disease. Response was assessed according to WHO criteria. Independent review of responses was not conducted. Poststudy follow-up occurred at least every 2 months for the full duration of survival. The primary end point was overall survival (all cause mortality). Secondary end points were response rate, time to disease progression (TTP), patient symptom assessment, QOL evaluation, and safety.
Statistical Methods This trial was designed to detect a 66.7% difference in median survival. The expected survival in the BSC arm was 12 weeks. The estimated median survival in the BSC plus oral topotecan arm was 20 weeks. Although initial sample size calculations determined that 220 patients (110 per arm) were needed to assess a survival benefit for topotecan with 90% power and a significance level of .05, recruitment was slower than expected. A formal protocol amendment was implemented to terminate the study once 125 deaths had been reported, thus providing 80% power to assess a survival benefit for topotecan at a .05 significance level. This point was reached when 141 patients had been recruited. No interim analyses were conducted. Overall survival was analyzed using the Kaplan-Meier method and compared using the log-rank test. Analyses of all secondary end points were descriptive; no adjustments were made for multiplicity. For the topotecan group, response rates were summarized along with a binomial 95% CI and TTP was summarized by Kaplan-Meier estimates. All P values are two sided. For the PSA, a generalized estimating equations model using PROC GENMOD version 8.1 (SAS Institute, Cary, NC) was fitted to longitudinal symptom data across visits to estimate the treatment effect on each of the symptoms (response was categorized as favorable or unfavorable). A logit link function along with exchangeable correlation structure was used for fitting the model. The rate of change in EQ-5D score in each arm was evaluated with a longitudinal analysis using a mixed model with change from baseline in score as response. Visual analog scale results were summarized using descriptive statistics.
Patients Patients were recruited from 40 centers in Europe, Canada, and Russia. Between November, 2000, and March, 2004, a total of 141 patients were randomly assigned: 70 to BSC and 71 to topotecan. Patient demographics were well matched between arms, particularly with respect to the major prognostic variables of PS and sex (Table 1). The median TFI after first-line therapy was 90 days on BSC and 84 days on topotecan. The most commonly received first-line chemotherapeutic agents were cisplatin or carboplatin (77% of patients in the BSC group and 80% in the topotecan group) and etoposide (74% in the BSC group and 76% in the topotecan group), consistent with current guidelines.16-18
Median time on study was 7.8 weeks in the BSC group and 12.3 weeks in the topotecan group. In total, 141 patients were evaluated for efficacy. More patients in the topotecan group completed the study (70% v 53%; Table 2). Three patients in the BSC arm had no postbaseline evaluations (lost to follow-up [one patient], death from disease progression [one patient], and withdrawal to begin chemotherapy [one patient]) and one patient in the topotecan arm did not receive treatment (infection-related death). Thus 67 patients in the BSC arm and 70 patients in the topotecan arm were evaluated for toxicity and QOL.
Delivered Chemotherapy A total of 278 topotecan courses were administered (median, 4; range, 1 to 10). Sixty-nine patients (99%) took 90% of their prescribed capsules. Patients in the BSC group were observed for the equivalent of a median of three courses (range, 1 to 13). Topotecan dose reduction occurred in 16 courses (8%) primarily due to hematologic toxicity (13 courses, 6%). Dose delays occurred in 41 topotecan courses (20%) most commonly for hematologic toxicity (25 courses, 12%). Dose escalation of topotecan occurred in 39 courses (14%). The median topotecan dose intensity achieved was 3.77 mg/m2/wk representing 98% of the scheduled dose. Some patients who were randomly assigned to receive BSC alone withdrew consent and elected to receive standard intravenous chemotherapy. In all, 13 patients in each arm (18.3% on BSC and 18.6% on topotecan) received poststudy chemotherapy either alone or in combination with other therapy such as radiotherapy and surgery. In addition, poststudy radiotherapy alone was received by seven patients (10%) in the topotecan arm and one patient (1%) in the BSC arm. Crossover to topotecan was not allowed by protocol.
Supportive Care
Efficacy Overall survival was significantly longer in the topotecan group (Fig 1; log-rank P = .01). The median survival times were 13.9 weeks (95% CI, 11.1 to 18.6) in the BSC arm and 25.9 weeks (95% CI, 18.3 to 31.6) in the topotecan arm. Six-month survival rates were 26% in the BSC group and 49% in the topotecan group.
Prolongation of survival in the topotecan group was preserved when analyzed according to sex, TFI from prior therapy ( 60 days or > 60 days), PS (0/1 or 2), and presence of liver metastases (Fig 2). Even for the group of patients considered least likely to benefit from therapy (those with TFI of 60 days), the median survival on BSC was 13.2 weeks (95% CI, 7.0 to 21.0), and on topotecan 23.3 weeks (95% CI, 10.7 to 30.9). For patients with a PS 2, the median survival on BSC was 7.7 weeks (95% CI, 5.3 to 13.1) and on topotecan 20.9 weeks (95% CI, 13.4 to 26.9). These data are presented graphically in Figure 2. The 95% CIs for the hazard ratios indicate a survival trend favoring topotecan in all subgroups.
Fifty-nine subjects (83%) in the topotecan arm experienced progression. The median TTP in the topotecan arm was 16.3 weeks (95% CI, 12.9 to 20.0).
The overall response rate to topotecan was 7% and a further 44% of patients achieved stabilization of disease, which was confirmed after no less than 56 days (Table 4). Reponses according to the prospectively defined stratification of TFI
QOL Overall, measures of QOL favored the topotecan group. Baseline EQ-5D questionnaires were completed by 68 patients (96%) in the topotecan group and 65 patients (93%) in the BSC group. At least one postbaseline EQ-5D questionnaire was completed by 63 patients (89%) in the topotecan group and 49 patients (70%) in the BSC group. For all patients with data, the rate of deterioration per 3-month interval in EQ-5D scores was 0.20 (95% CI, 0.27 to 0.12) on BSC compared with 0.05 (95% CI, 0.11 to 0.02) on topotecan. The difference in rate of change was +0.15 (95% CI, 0.05 to 0.25) indicating that the EQ-5D score worsened significantly faster in the BSC arm. Odds ratios of individual symptoms evaluated by the PSA indicate a greater likelihood of achieving symptom improvement on topotecan for every symptom (Table 5). For shortness of breath, sleep interference, and fatigue, the odds ratio CIs indicate statistical superiority at the .05 significance level in favor of topotecan.
Toxicity In the topotecan group, grade 3/4 neutropenia, grade 3/4 thrombocytopenia, and grade 3/4 anemia occurred in 61%, 38%, and 25% of patients, respectively. Febrile neutropenia occurred in 3%. Among all patients on BSC, nonsepsis infection grade 2 occurred in eight patients (12%) in the BSC arm and 10 patients (14%) in the topotecan arm. Sepsis occurred in three patients (4%) in the topotecan group and one patient (1%) in the BSC group. In the topotecan arm, two patients (3%) received granulocyte colony-stimulating factor or granulocyte-macrophage colony-stimulating factor and two patients (3%) received erythropoietin. The most commonly occurring grade 3/4 nonhematologic toxicities were diarrhea (6%), fatigue (4%), vomiting (3%), and dyspnea (3%) in the topotecan group and dyspnea (9%), fatigue (4%), and cough (2%) in the BSC group. Toxic deaths occurred in four patients (6%) in the topotecan arm with three due to hematologic toxicity. Of these three deaths, one was attributed to severe cytopenia and infection, one to neutropenia and pneumonia, and one to neutropenia and thrombocytopenia. All cause mortality within 30 days of random assignment was 7% in the topotecan arm (five patients: progressive disease, one; drug toxicity, three; other reason, one) and 13% in the BSC arm (nine patients, all due to progressive disease). Patients on BSC were at greater risk of death compared with patients on topotecan at all stages of the study.
This study has successfully quantified the clinical benefit associated with active chemotherapy in patients with relapsed SCLC. Treatment with oral topotecan prolonged survival and improved QOL compared with BSC alone and the improvements can be considered clinically and statistically significant. In patients with sensitive SCLC, the study confirms the previous observation of survival benefit and symptom palliation associated with active chemotherapy. More importantly, the treatment dilemma concerning patients with short TFI or PS 2 is also resolved. This study suggests that with oral topotecan the benefits of therapy outweigh the risks in all patient groups and therefore all subgroups of patients with relapsed SCLC (sensitive or resistant) should now be considered for this treatment. Two randomized studies have shown that similar clinical activity is achieved with either oral or intravenous topotecan in SCLC.9,10 In a different setting, a survey of patients showed that patients prefer oral over intravenous chemotherapy in the palliative setting if clinical activity is not compromised.19 Thus, physicians treating patients with recurrent SCLC would have an effective oral option when patients identify this preference. With the median survival of the treated group at 25.9 weeks and the fact that around 50% of these patients in both arms had a good PS of 0 to 1 at study entry, and 42% and 59%, respectively, of patients had a TFI longer than 90 days, one could argue that this was a group of patients who should have been offered standard intravenous chemotherapy. We did not collect data on specific comorbidities or the reasons why individual patients were not offered standard intravenous chemotherapy by their oncologists. However, one recent study suggests that our study was indeed a real clinical situation. Sundstrom et al20 randomly assigned and treated patients at diagnosis with either etoposide and cisplatin or cyclophosphamide, epirubicin, and vincristine; at relapse patients received the alternate, crossover regimen. Of 286 patients randomly assigned initially, only 120 were suitable for second-line therapy; the remaining 166 patients received BSC. In the group offered BSC alone, 38% had a PS of 0 to 1 and 43% had a TFI longer than 3 monthsvery similar to our trial group. The median survival in the crossover arms were 3.9 and 4.5 months, respectively, for etoposide and cisplatin and cyclophosphamide, epirubicin, and vincristine.20 Other important clinical issues have been addressed. The number of patients deriving benefit from oral topotecan exceeds the 7% who achieved a partial response. This response rate is lower than that reported in previous studies with patients selected on their sensitivity to previous treatments. This corroborates previous suggestions that stabilization of disease as measured by WHO criteria is associated with clinical benefit,21 though we accept that the data on symptom control in both arms is less reliable than if a placebo had been included. The natural course of untreated SCLC has been defined, and this study will provide the benchmark against which future treatment strategies in this indication can be judged.
Although all authors completed the disclosure declaration, the following authors or their immediate family members indicated a financial interest. No conflict exists for drugs or devices used in a study if they are not being evaluated as part of the investigation. For a detailed description of the disclosure categories, or for more information about ASCOs conflict of interest policy, please refer to the Author Disclosure Declaration and the Disclosures of Potential Conflicts of Interest section in Information for Contributors.
Supported by GlaxoSmithKline, Middlesex, United Kingdom. Presented in part at the International Association for the Study of Lung Cancers 11th World Conference on Lung Cancer, Barcelona, Spain, July 3-6, 2005. The trial was designed by the sponsor (G.S.K.) who held and analyzed the data. The contents of this article were reviewed and approved by all authors. Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.
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Copyright © 2006 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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