Management of small cell lung cancer

Randomized-controlled phase II trial of salvage chemotherapy after immunization with a TP53-transfected dendritic cell-based vaccine (Ad.p53-DC) in patients with recurrent small cell lung cancer

Small cell lung cancer TP53 mutations lead to expression of tumor antigens that elicits specific cytotoxic T-cell immune responses. In this phase II study, dendritic cells transfected with wild-type TP53 (vaccine) were administered to patients with extensive-stage small cell lung cancer after chemotherapy. Patients were randomized 1:1:1 to arm A (observation), arm B (vaccine alone), or arm C (vaccine plus all-trans-retinoic acid). Vaccine was administered every 2 weeks (3 times), and all patients were to receive paclitaxel at progression. Our primary endpoint was overall response rate (ORR) to paclitaxel. The study was not designed to detect overall response rate differences between arms. Of 69 patients enrolled (performance status 0/1, median age 62 years), 55 were treated in stage 1 (18 in arm A, 20 in arm B, and 17 in arm C) and 14 in stage 2 (arm C only), per 2-stage Simon Minimax design. The vaccine was safe, with mostly grade 1/2 toxicities, although 1 arm-B patient experienced grade 3 fatigue and 8 arm-C patients experienced grade 3 toxicities. Positive immune responses were obtained in 20% of arm B (95% confidence interval [CI], 5.3-48.6) and 43.3% of arm C (95% CI 23.9-65.1). The ORRs to the second-line chemotherapy (including paclitaxel) were 15.4% (95% CI 2.7-46.3), 16.7% (95% CI 2.9-49.1), and 23.8% (95% CI 9.1-47.5) for arms A, B, and C, with no survival differences between arms. Although our vaccine failed to improve ORRs to the second-line chemotherapy, its safety profile and therapeutic immune potential remain. Combinations with the other immunotherapeutic agents are reasonable options.

Small cell lung cancer

Neuroendocrine tumors account for approximately 20% of lung cancers; most (≈15%) are small cell lung cancer (SCLC). These NCCN Clinical Practice Guidelines in Oncology for SCLC focus on extensive-stage SCLC because it occurs more frequently than limited-stage disease. SCLC is highly sensitive to initial therapy; however, most patients eventually die of recurrent disease. In patients with extensive-stage disease, chemotherapy alone can palliate symptoms and prolong survival in most patients; however, long-term survival is rare. Most cases of SCLC are attributable to cigarette smoking; therefore, smoking cessation should be strongly promoted.

Phase II study of cisplatin/etoposide and endostar for extensive-stage small-cell lung cancer

PURPOSE

To investigate the efficacy and safety of endostar, a novel recombinant human endostatin, plus cisplatin, and etoposide in patients with extensive-stage small-cell lung cancer (ED-SCLC).

PATIENTS AND METHODS

Chemotherapy-naïve patients with histologically confirmed, measurable ED-SCLC were enrolled. Treatment consisted of cisplatin (25 mg/m(2)) administered intravenously (IV) on days 1-3; etoposide (120 mg/m(2)) administered intravenously (IV) on days 1-3; endostar (15 mg) administered intravenously (IV) on days 1-14 every 21 days for up to four cycles. The primary objective was to assess the progression-free survival (FPS). Secondary objectives were to assess the objective response rate, median overall survival (OS), and treatment-related toxicity.

RESULTS

Thirty-three patients were enrolled, the median age of the patients was 53 years (range, 29-74), twenty-three patients (69.7%) were men and 10 patients were women. Eastern Cooperative Oncology Group performance status scores were 0, 1,and 2 in 30.3, 60.6, and 9.1% of the patients, respectively. The overall response rate was 69.7%, one patient (3%) had a complete response, and 22 patients (66.7%) had partial responses. Five patients (15.1%) had stable disease; the median PFS was 5.0 months (95% CI, 4.2-5.6 months), and the 6-month PFS was 33.3%. The median OS was 11.5 months (95% CI, 9.6-13.4 months), and the 1-year OS was 38.1% (95% CI, 26-50.1%). Sixteen patients (48.5%) had at least one grade 3/4 adverse events; the most common grade 3/4 hematologic toxicity included neutropenia in 57.6%, thrombocytopenia in 12.1% of patients. The most common grade 3/4 non-hematologic toxicities included fatigue in 15.2%, nausea/vomiting in 9.1%, diarrhea in 6.1%, anorexia in 6.1%, mucositis in 6.1% of patients.

CONCLUSION

The addition of rh-endostain to cisplatin and etoposide in patients with ED-SCLC results in slightly improved PFS and OS relative to historical controls who received this chemotherapy regimen alone. This regimen appears to be well tolerated; the promising results suggest the further randomized phase III trial to define endostar's impact on SCLC treatment.

Retrospective review of extra-pulmonary small cell carcinoma at King Chulalongkorn memorial hospital cases during 1998-2005

OBJECTIVE

The aim of this study was to review cases of extra-pulmonary small cell carcinoma (EPSCC), including their clinical manifestations and treatment outcomes.

METHODS

We retrospectively reviewed the medical records and pathological reports of patients who were diagnosed with EPSCC from 1998 to 2005.

RESULTS

Overall 21 EPSCC patients were eligible for this study. The most common primary sites were the gastrointestinal organs and the nasal cavity. Eleven patients (52.3%) had limited disease (LD) and 10 patients (47.7%) had extensive disease (ED). Nine patients underwent radical surgery alone, four received only radical radiation and two received only palliative chemotherapy. Two patients received adjuvant radiation or chemotherapy following surgical resection and one received a combination of all three treatment modalities. Three patients declined specific treatment and were treated with best supportive care. The median overall survival in the ED group was only 3 months (range 1-16 months), compared to 30 months (range 20-61 months) for LD. EPSCC of pancreas demonstrated a favorable clinical outcome with treatment, whereas primary EPSCC of the liver, esophagus and rectum had an aggressive natural history and a poor response to treatment.

CONCLUSION

Our report suggests that EPSCC may have a different biology from that of pulmonary small cell carcinoma. When detected at an early stage, EPSCC may have an excellent prognosis with treatment. Additional studies involving more patients with EPSCC are warranted to further define the optimal roles of each treatment modality.

INGN-225: a dendritic cell-based p53 vaccine (Ad.p53-DC) in small cell lung cancer: observed association between immune response and enhanced chemotherapy effect

IMPORTANCE OF THE FIELD

Novel approaches are needed for patients with small cell lung cancer (SCLC), as response after relapse is poor with standard therapies. p53 gene mutations often occur, resulting in tumoral protein overexpression and allowing for their recognition by p53-specific cytotoxic T cells.

AREAS COVERED IN THIS REVIEW

We describe the characteristics and manufacturing of INGN-225, a p53-modified adenovirus-tranduced dendritic cell vaccine, and review available data, to understand INGN-225's role in SCLC treatment. We discuss our pre-clinical, early Phase I/II, and ongoing randomized Phase II studies.

WHAT THE READER WILL GAIN

INGN-225 was well tolerated (all toxicities

TAKE HOME MESSAGE

INGN-225 is safe, induces a significant immune response, and appears to sensitize SCLC to subsequent chemotherapy. Improvements in immune response induction and understanding the chemotherapy-immunotherapy synergism will determine INGN-225's future role as an anticancer therapy.

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Key Words

• adenovirus
• dendritic cells
• ingn-225
• p53 gene
• small cell lung cancer

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MESH Headings

• Animals
• Cancer Vaccines/administration & dosage
• Cancer Vaccines/adverse effects
• Cancer Vaccines/therapeutic use
• Clinical Trials, Phase I as Topic
• Clinical Trials, Phase II as Topic
• Dendritic Cells/immunology
• Humans
• Immunotherapy
• Lung Neoplasms/immunology
• Lung Neoplasms/therapy
• Randomized Controlled Trials as Topic
• Small Cell Lung Carcinoma/immunology
• Small Cell Lung Carcinoma/therapy
• Tumor Suppressor Protein p53/immunology

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Grants

• K24 CA128953 NCI NIH HHS
• P50 CA119997 NCI NIH HHS
• 5P50- CA- 119997 NCI NIH HHS

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Affiliation(s)

Alberto A Chiappori Department of Thoracic Oncology, H Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL 33612, USA.
Hatem Soliman
William E Janssen
Scott J Antonia
Dmitry I Gabrilovich

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Collaborators Collapse

Alpha-methylacyl CoA racemase in pulmonary adenocarcinoma, squamous cell carcinoma, and neuroendocrine tumors: expression and survival analysis

CONTEXT

Alpha-methylacyl CoA racemase (AMACR) is an oxidative enzyme involved in isomeric transformation of fatty acids entering the beta-oxidation pathway. AMACR serves as a useful marker in establishing a diagnosis of prostatic malignancy; however, limited information is available in regard to its presence in pulmonary neoplasms.

OBJECTIVE

To investigate AMACR expression within a spectrum of lung carcinomas and its correlation with patients' survival.

DESIGN

Four hundred seventy-seven pulmonary carcinomas, including 150 squamous cell carcinomas, 150 adenocarcinomas, 46 typical carcinoids, 31 atypical carcinoids, 28 large cell neuroendocrine carcinomas, and 72 small cell carcinomas, were studied immunohistochemically using tissue microarray-based samples.

RESULTS

Overall, pulmonary tumors were positive for AMACR in a significant percentage (47%) of cases. Among tumor types, 22% of squamous cell carcinoma, 56% of adenocarcinoma, 72% of typical carcinoid, 52% of atypical carcinoid, 70% of large cell neuroendocrine carcinoma, and 51% of small cell lung carcinoma were positive for AMACR. Furthermore, the Kaplan-Meier analysis revealed that the patients with AMACR-positive small cell carcinoma had better survival (19% vs 5% after 5 years, P = .04) than patients with AMACR-negative tumors. Such survival advantage was seen for patients with stage I-II (P = .01) but not stage III-IV small cell carcinomas (P = .58).

CONCLUSIONS

These results indicate that, similar to prostate cancer, the overexpression of AMACR frequently occurs in pulmonary carcinomas. Additionally, its positive correlation with outcome of stage I-II small cell lung carcinoma warrants further investigation of the AMACR role in the prognosis of this tumor.

A phase II trial of cisplatin and irinotecan alternating with doxorubicin, cyclophosphamide and etoposide in previously untreated patients with extensive-disease small-cell lung cancer

PURPOSE

The aim of this trial was to investigate the efficacy and safety of cisplatin (P) and irinotecan (I) (PI) alternating with doxorubicin (A), cyclophosphamide (C) and etoposide (E) (ACE) in patients with extensive-disease small-cell lung cancer (ED-SCLC).

PATIENTS AND METHODS

Patients with previously untreated ED-SCLC were enrolled in this trial. In the first, third and fifth cycles, PI (P: 60 mg/m(2) on day 1; I: 60 mg/m(2)/day on days 1, 8 and 15) was administered, whereas ACE (A: 50 mg/m(2) on day 1; C: 750 mg/m(2) on day 1; E 80 mg/m(2)/day on days 1-3) was given in the second, fourth and sixth cycles. Each cycle was repeated every 4 weeks. At the end of six cycles, patients who had obtained a complete response were given prophylactic cranial irradiation.

RESULTS

In total, 28 patients were enrolled, of whom 27 were assessable for efficacy and safety. Objective responses, including 4 (15%) complete responses, were observed in 25 patients (93%). Median survival time was 12.9 months. The principal toxicity was myelosuppression; grade 4 neutropenia and thrombocytopenia were observed in 89 and 4%, respectively. Febrile neutropenia occurred in 30% of patients. Diarrhea was mild (grade 3-4; 4%). All toxicities were reversible and there were no treatment-related deaths. The mean percentage of the delivered doses, relative to the projected doses, of PI and ACE were 84.6 and 91.1%, respectively.

CONCLUSIONS

These results indicate the PI-ACE regimen to have promising activity against ED-SCLC with moderate toxicities.

Prevalence and Predictors of Symptoms in the Terminal Stage of Lung Cancer

BACKGROUND

There is little knowledge concerning the prevalence and predictors of symptoms in the terminal stage of lung cancer.

METHODS

We examined, retrospectively, all cases of lung cancer diagnosed from 1990 to 1996 in a defined hospital area in Norway. All medical records from general practitioners, nursing homes, and hospitals were investigated. A total of 271 cases were diagnosed, and 247 of 253 deaths (98%) were analyzed.

RESULTS

In the terminal 8 weeks, pain was recorded in 85% of the patients, psychological symptoms (anxiety, insomnia, and/or depression) in 71%, dyspnea in 54%, neurologic symptoms in 28%, cough in 24%, nausea in 21%, and hemoptysis in 9%. Young age (p = 0.02) and small cell lung carcinoma (p = 0.03) were risk factors for psychological symptoms. Terminal dyspnea was more frequent in patients with stage III (p = 0.002) and nausea in stage IV (p = 0.02) at the time of diagnosis, while cough (p = 0.04) occurred more often in non-small cell lung carcinoma. Terminal pain was independent of gender, age, performance status, stage, and histology.

CONCLUSION

In a community health service encompassing all lung cancer patients, pain, psychological symptoms, and dyspnea were frequent complaints in the terminal phase. Terminal dyspnea and nausea were associated with staging at the time of diagnosis, and terminal cough and nausea were associated with histology.

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.

A phase I study of 3-day topotecan and cisplatin in elderly patients with small-cell lung cancer

PURPOSE

The aim of this phase I study was to determine the maximum-tolerated dose (MTD) in elderly patients with small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Patients aged over 75 years with previously untreated SCLC were enrolled in this study. Both topotecan and cisplatin were administered on days 1-3 and repeated every 3 weeks. The starting dose of topotecan was 0.5 mg/m2/day, while cisplatin was fixed at the dose of 20 mg/m2/day. Patients with limited disease (LD) SCLC received thoracic irradiation after the completion of chemotherapy.

RESULTS

Twenty-one elderly patients were enrolled in this study and received a total of 59 cycles. The major hematological toxicity was neutropenia and non-hematological toxicities including diarrhea were generally mild and reversible. The MTD of topotecan was determined as 1.2 mg/m2/day. The recommended phase II study dose of topotecan was determined as 1.0 mg/m2/day with cisplatin 20 mg/m2/day daily for 3 days. An objective response was observed in 6 of 10 patients (60%) with LD-SCLC and 6 of 11 (55%) with extensive disease (ED) SCLC. The median survival time in patients with LD-SCLC and those with ED-SCLC were 16.0 and 11.0 months, respectively.

CONCLUSION

The combination chemotherapy of 3-day topotecan and cisplatin appears to be tolerable and effective in elderly patients with SCLC.

Extensive Stage Small Cell Lung Cancer Presenting as an Acute Perforated Appendix: Case Report and Review of the Literature

Malignancies of the appendix are uncommon; a small subset of these lesions are actually metastatic cancers. In some rare cases, these lesions can cause obstruction, appendicitis, and perforation. M.K. is a 54-year-old man who presented to our institution with a 1-day history of right lower quadrant pain and a past medical history significant only for a 75-pack-year smoking history. CT scan revealed a perforated appendix, and the patient was taken to the operating room where a gangrenous appendix was removed uneventfully. Two days post-procedure, the patient was found to have acute mental status changes, requiring intubation and transfer to the surgical intensive care unit. As part of a workup, a CT scan of the head revealed multiple lesions compatible with metastatic disease. At that point, the pathology from the appendix came back as small cell lung cancer. Chest CT revealed hilar adenopathy and a hilar mass. The patient received emergent whole-brain irradiation therapy with improvement in his mental status, allowing him to be extubated and discharged from the hospital within 10 days of admission. Surgeons should remember that an underlying oncologic process may be the etiology of appendicitis in a small but important subgroup of patients.

Outcome of patients with pulmonary carcinoid tumors receiving chemotherapy or chemoradiotherapy

STUDY OBJECTIVES

To determine the outcome of patients with pulmonary typical and atypical carcinoid tumors treated with chemotherapy with or without radiotherapy.

METHODS

Patients with pulmonary neuroendocrine tumors treated at our institution from 1990 to 2001 were identified. The medical records of patients with diagnoses of typical or atypical pulmonary carcinoids were reviewed for the presence of evaluable disease, treatment with chemotherapy with or without radiotherapy, response to these treatments, survival and cause of death.

RESULTS

Eighteen patients with typical (n = 8) or atypical (n = 10) pulmonary carcinoid tumors who were treated with chemotherapy with or without radiotherapy were identified. Of these, four received chemotherapy plus chest radiotherapy. Three of these had stable disease and one had a partial response. One of the patients with stable disease to chemoradiotherapy subsequently received chemotherapy alone, to which he had a complete response. Fourteen additional patients were treated with 18 chemotherapy regimens. There were two partial responses, eight stable disease, seven progressive disease and one allergic reaction precluding further treatment. The overall response rate to any chemotherapy was 3/15 (20%, 95% CI 0.07-0.45), and the best overall response rate to chemotherapy with or without chest radiotherapy was 4/18 (22%, 95% CI 0.09-0.45). Median overall survival was 20 months (95% CI 0-51 months).

CONCLUSIONS

Patients with typical and atypical pulmonary carcinoid tumors can respond to chemotherapy with or without chest radiotherapy, though with response rates that appear less than those of small cell lung cancers. Further characterization of pulmonary carcinoid tumors and study of treatment alternatives for unresectable disease is warranted.

Topotecan in the Treatment of Relapsed Small Cell Lung Cancer Patients with Poor Performance Status

Topotecan is the only single-agent therapy approved by the U.S. Food and Drug Administration for the treatment of patients with recurrent small cell lung cancer (SCLC). Poor performance status (PS) at the time of relapse can hinder the ability of a patient to tolerate second-line chemotherapy. To investigate the feasibility of topotecan in the treatment of relapsed SCLC patients with PS 2 scores, we retrospectively analyzed data from five clinical trials that included 479 patients who were treated with single-agent topotecan at a dose of 1.5 mg/m2/day on days 1-5 of a 21-day course. Of these patients, 381 had a PS 0 or 1 and 98 had a PS 2. Topotecan was well tolerated by both patient groups. Hematologic toxicities were generally manageable, and neutropenia was noncumulative. With the exception of grade 3/4 anemia, the incidences of severe hematologic toxicities were not statistically different between the two groups. The nonhematologic toxicity profiles were also similar in the two patient groups. Treatment provided similar benefits, including antitumor response rates and symptom palliation, in PS 0/1 and PS 2 patients. As expected, the median overall survival time was shorter in patients with worse PS scores; the median overall survival times were 36.3 weeks, 25.4 weeks, and 16 weeks for PS 0, PS 1, and PS 2 patients, respectively. In conclusion, treatment with topotecan is feasible and well tolerated in patients with relapsed SCLC with suboptimal PS scores.

New agents in the treatment of small-cell lung cancer: focus on gemcitabine

Small-cell lung cancer (SCLC) accounts for 20%-25% of all new cases of lung cancer and represents the sixth most commonly diagnosed cancer in the United States. Given the tumor's systemic nature and chemoresponsiveness, chemotherapy has become the cornerstone of its management. Chemotherapy significantly prolongs survival; however, most of the patients still die within 2 years of diagnosis. Combination chemotherapy represents the treatment of choice for this disease. In the United States, cisplatin/etoposide is the regimen most frequently used for the first-line therapy of SCLC patients because of its better therapeutic index. Upon recurrence, topotecan is the Food and Drug Administration-approved treatment based on a phase III trial that showed no statistically significant differences in survival or response for topotecan compared with CAV (cyclophosphamide/doxorubicin/vincristine) but a better disease-related symptom improvement compared to baseline favoring the topoisomerase I inhibitor. Newer agents, with novel mechanisms of action, have shown activity against SCLC and are being tested in many different combinations. Among these agents, gemcitabine has attractive mechanisms of action and toxicity profile. Gemcitabine is a pyrimidine nucleoside antimetabolite, analogue to cytosine arabinoside, which through incorporation into the DNA leads to inhibition of DNA synthesis and cytotoxicity. As a single agent, gemcitabine has modest activity against SCLC. However, like with many other drugs, response rates improve when gemcitabine is used in combination regimens. Phase II and III studies of combinations with classic drugs for the management of SCLC patients such as cisplatin and/or etoposide and gemcitabine demonstrate comparable results to those of standard therapies. The gemcitabine/paclitaxel and gemcitabine/topoisomerase I inhibitor combinations are also of great interest, and preliminary results in previously treated patients are promising. The proper role of gemcitabine in the treatment of patients with SCLC awaits future testing in randomized phase III trials.

Treatment of relapsed small-cell lung cancer--a focus on the evolving role of topotecan

Despite the high response rates to chemotherapy, small-cell lung cancer (SCLC) is among the most lethal malignancies. Long-term survival is anecdotal for patients with extensive disease; 5-years survival is < or =5% for those with limited disease. All patients with extensive disease and most patients with limited disease will experience disease progression and become candidates for second-line therapy. Although a number of agents have demonstrated antitumor activity in relapsed SCLC, including paclitaxel, docetaxel, etoposide, cisplatin, and carboplatin, topotecan is the only single agent currently approved in the United States for the treatment of recurrent disease. Topotecan is a novel topoisomerase I inhibitor with established antitumor activity in recurrent SCLC and has a predictable, noncumulative toxicity profile. Furthermore, topotecan has been shown to provide symptom improvement in this predominantly palliative setting. Evidence also suggests that topotecan readily penetrates the blood-brain barrier and might be active in the relatively large subset of SCLC patients who experience brain metastases. This article reviews the clinical utility of topotecan in recurrent SCLC, including its efficacy, tolerability, and quality-of-life effect, when used as monotherapy and in novel combination regimens.

Emerging Role of Topotecan in First-Line Therapy of Small-Cell Lung Cancer

Topotecan, a novel topoisomerase I inhibitor, is an established treatment for patients with recurrent small-cell lung cancer (SCLC), with antitumor response rates of approximately 20% and median survival of approximately 32 weeks in patients with extensive-stage disease. Topotecan's comparable activity relative to other agents used in SCLC and its novel mechanism of action, noncumulative toxicity, and in vitro synergy with other active agents have provided the rationale for investigating topotecan in first-line therapy. Furthermore, topotecan penetrates the blood-brain barrier and is potentially useful for the relatively large subset of patients with SCLC and brain metastases. In early studies of topotecan in brain metastases, encouraging antitumor activity has been observed. In several feasibility and phase II studies of topotecan as single-agent therapy in patients with extensive- and limited-stage tumors and as part of novel first-line combination regimens, overall response rates have ranged from 42% to 100%. Complete responses of 3%-67% and partial responses of 33%-80% have been observed in first-line therapy. Furthermore, the median overall survival in patients receiving topotecan in first-line therapy has ranged from approximately 8 months (extensive-stage disease) to 20 months (limited-stage disease). The most frequent adverse events associated with topotecan-based regimens include grade 3/4 neutropenia and thrombocytopenia that often require the incorporation of growth factor support into the treatment regimen. Nonhematologic adverse events associated with topotecan-based combination regimens have been mild or primarily attributed to other agents in the combination. Alternative doses and schedules (3 consecutive days and weekly) are being explored because they appear to be associated with considerably less myelosuppression. Although several trials have established the feasibility and activity of topotecan in first-line therapy of patients with SCLC, randomized phase III studies with comparison to standard therapy will be required to confirm a potential role for this active agent and to determine the optimal dosing regimen.