Role of recombinant interferon alfa-2a maintenance in patients with limited-stage small-cell lung cancer responding to concurrent chemoradiation: a Southwest Oncology Group study

Advances in Small-Cell Lung Cancer (SCLC) Translational Research

Over the past several years, we have witnessed a resurgence of interest in the biology and therapeutic vulnerabilities of small-cell lung cancer (SCLC). This has been driven in part through the development of a more extensive array of representative models of disease, including a diverse variety of genetically engineered mouse models and human tumor xenografts. Herein, we review recent progress in SCLC model development, and consider some of the particularly active avenues of translational research in SCLC, including interrogation of intratumoral heterogeneity, insights into the cell of origin and oncogenic drivers, mechanisms of chemoresistance, and new therapeutic opportunities including biomarker-directed targeted therapies and immunotherapies. Whereas SCLC remains a highly lethal disease, these new avenues of translational research, bringing together mechanism-based preclinical and clinical research, offer new hope for patients with SCLC.

Systemic therapy for limited stage small cell lung carcinoma

Systemic treatment in small cell lung carcinoma has been a challenge for oncologists for decades. The high propensity for recurrence is usually due to distant metastasis, which makes systemic treatment an essential component of treatment in small cell lung carcinoma. The regimen of cisplatin and etoposide (established in the mid-1980’s) concurrently with thoracic radiotherapy followed by prophylactic cranial irradiation (PCI) remains the standard of care in limited stage disease. Despite numerous trials, this regimen has not been improved upon. The standard combination regimen of cisplatin and etoposide has been compared to alternative platinum-containing regimens with drugs like epirubicin, irinotecan, paclitaxel, topotecan, pemetrexed, amrubicin and belotecan. Non-platinum containing regimens like ifosfamide and etoposide have also been tested. Attempts to intensify therapy have included the addition of a third drug like paclitaxel, ifosfamide, tirapazamine, tamoxifen, and thalidomide. Maintenance therapy following induction with chemotherapy, vandetanib and interferon-alpha have also been attempted. Molecularly directed targeted therapies and immunotherapeutic agents are areas of active research. In this review, we discuss the various systemic therapy options in limited stage small cell lung carcinoma, from the historical regimens to the modern-day therapy and promising areas of research. We also discuss the role of growth factors, the optimal number of chemotherapy cycles, the use of prognostic and predictive factors, the optimal timing of chemotherapy and the treatment of special populations of patients including older patients, and patients with comorbidities.

Update on the Biology, Management, and Treatment of Small Cell Lung Cancer (SCLC)

Small-cell lung cancer (SCLC) accounts for 13-15% of all new lung cancer cases in the US. The tumor has a tendency to disseminate early resulting in 80-85% of patients being diagnosed with extensive disease (ES-SCLC). Chemotherapy has provided SCLC patients considerable survival benefits over the past three decades. Nonetheless, most patients relapse and rarely survive beyond 2 years. Despite consistent overall response rates of ≥50%, until recently, median survival times and 2-year survivals only ranged between 7-10 months and 10-20%, respectively. Several chemotherapy agents possess activity against SCLC, both, as single agents and in combinations but etoposide-platinum emerged as the preferred first line regimen. Upon relapse, many patients remain candidates for additional therapy. However, the sensitivity of relapsed SCLC to further therapies is markedly reduced and dependent upon the level and duration of response to the initial treatment (platinum-sensitive vs. resistant relapse). Multiple factors suggest a therapeutic role for immunotherapy in SCLC: SCLC has been associated with immune-mediated paraneoplastic processes (cerebellar degeneration, limbic encephalitis, and Lambert-Eaton syndrome) and patients presenting with these paraneoplastic syndromes have shown more favorable outcomes, suggesting an underlying immune response mechanism.Comprehensive genomic profiling of SCLC indicates that the majority lack functional p53 (90%) and Rb1 (65%). These universal genetic aberrations facilitate poor genomic stability, thus perpetuating the generation of tumor associated antigens, amenable to targeting with immunotherapy.SCLC has one of the highest mutational loads, likely a reflection of the myriad of insults inflicted by smoking-related carcinogens. The relationship between tumor mutational load and response to immune checkpoint inhibitors has been established in multiple solid tumors, including preliminary results in relapsed SCLC. In this manuscript, we review the early (some failed and discontinued, some partly successful, and still ongoing) attempts to incorporate immunotherapy (particularly vaccine based approaches) to the treatment of SCLC, and the latest attempts (mostly incorporating the use of checkpoint inhibitors), including those with favorable but preliminary results (CheckMate 032, Keynote 028 and 158), and those with more definitive positive (iMpower 133 and CASPIAN) and negative (CheckMate 331 and 451) results.

Combining Radiation Therapy With Interferons: Back to the Future

Radiation therapy has been linked to the induction of an intratumoral type I interferon (IFN) response, which positively affects the response to treatment. This has spiked the interest to combine radiation therapy with IFN-based treatment. Interestingly, this combination treatment has been considered previously, since preclinical studies demonstrated a radiosensitizing effect of interferons. As a result, multiple clinical trials have been performed combining radiation therapy with interferons in different tumor types. Although potential benefit has been suggested, the outcomes of the trials are diverse and challenging to interpret. In addition, increased grade ≥3 toxicity frequently resulted in a negative recommendation regarding the combination therapy. The latter appears premature because many studies were small and several aspects of the combination treatment have not yet been sufficiently explored to justify such a definite conclusion. This review summarizes the available literature on this combination therapy, with a focus on IFN-α and IFN-β. Based on preclinical studies and clinical trials, we evaluated the potential opportunities and describe the current challenges. In addition, we identify several issues that should be addressed to fully exploit the potential benefit of this combinatorial treatment approach.

[Research Progression of Maintenance Therapy in Small Cell Lung Cancer]

肺癌是世界上最常见的恶性肿瘤之一，其中小细胞肺癌发生率约15%。小细胞肺癌对一线化疗高度敏感，但多数患者在一线治疗缓解后很快出现复发进展，因此，自20世纪80年代起已开展不少小细胞肺癌维持治疗的相关临床研究，涉及到化疗药物、生物制剂及分子靶向药物。但其结果仍存在争论，现对该方面内容综述如下。

Small cell lung cancer: will recent progress lead to improved outcomes?

Small cell lung cancer (SCLC) is an aggressive neuroendocrine malignancy with a unique natural history characterized by a short doubling time, high growth fraction, and early development of widespread metastases. Although a chemotherapy- and radiation-sensitive disease, SCLC typically recurs rapidly after primary treatment, with only 6% of patients surviving 5 years from diagnosis. This disease has been notable for the absence of major improvements in its treatment: Nearly four decades after the introduction of a platinum-etoposide doublet, therapeutic options have remained virtually unchanged, with correspondingly little improvement in survival rates. Here, we summarize specific barriers and challenges inherent to SCLC research and care that have limited progress in novel therapeutic development to date. We discuss recent progress in basic and translational research, especially in the development of mouse models, which will provide insights into the patterns of metastasis and resistance in SCLC. Opportunities in clinical research aimed at exploiting SCLC biology are reviewed, with an emphasis on ongoing trials. SCLC has been described as a recalcitrant cancer, for which there is an urgent need for accelerated progress. The NCI convened a panel of laboratory and clinical investigators interested in SCLC with a goal of defining consensus recommendations to accelerate progress in the treatment of SCLC, which we summarize here.

Treatment of small cell lung cancer

Treatment of small cell lung cancer (SCLC) remains a significant challenge for the oncologists. Attempts to improve the results of first-line treatment have all failed so far and no real progress has been made in last years, emphasizing the need for novel strategies of treatment and the development of validated biomarkers. Patients with limited disease and good performance status should be considered for concomitant chemoradiotherapy, followed by prophylactic cranial irradiation. Patients with extensive disease should be treated with a platinum-based chemotherapy (cisplatin or carboplatin); chest radiotherapy can be considered in patients achieving extra-thoracic complete response and prophylactic cranial irradiation is recommended for patients responsive to initial chemotherapy. A large number of molecular-targeted drugs and immunomodulators are currently in clinical development: however, only a better understanding of molecular biology of SCLC and the identification of molecular markers predictive of response to targeted agents will lead to advances in the treatment of SCLC.

Potential anti-tumor effect of IFN-λ2 (IL-28A) against human lung cancer cells

Interferon (IFN)-λs (IL-28A/IL-28B/IL-29) classified as type III IFNs, are the latest members identified of the interferon family. As with type I IFNs such as IFN-α, type III IFNs share antiviral and antitumor activity and may have fewer side effects due to a more selective receptor distribution. Therefore, type III IFNs may be clinically useful for human viral and malignant diseases. Here we demonstrate the potential anti-tumor effect of IFN-λ2 (IL-28A) against human lung cancer cells. All lung cancer cell lines that we examined expressed both IFN-λ receptors (IL-28R1 and IL-10R2). Lung cancer cells with epidermal growth factor receptor (EGFR) mutations were more sensitive to IFN-λ2 treatment compared with cells with KRAS mutations. HCC827 cells with an EGFR mutation treated with IFN-λ2 underwent growth suppression and apoptotic cell death by STAT1 phosphorylation. Administration of neutralizing antibodies to IFN-λ inhibited caspase-3/7 activity induced by IFN-λ2. Finally, in vivo luminescent imaging also demonstrated the anti-tumor effect of IFN-λ2 in a cancer cell transplant animal model. Taken together, IFN-λ2 would be a new therapeutic agent for clinical lung cancers with EGFR mutations.

Interferon-alpha improves docetaxel antitumoral and antimetastatic efficiency in Lewis lung carcinoma bearing mice

AIMS

Interferon-alpha (IFN-α) was shown to reduce P-glycoprotein (P-gp) expression and activity in several tissues. The purpose of this study was to evaluate the impact of IFN-α pretreatment on the antitumoral and antimetastatic, Docetaxel (DTX, P-gp substrate), on Lewis Lung Cancer (3LL) bearing mice and to correlate it to DTX pharmacokinetics.

MAIN METHODS

Six groups of C57/Bl6 mice received subcutaneous (s.c.) 2.10(6) 3LL cells, then IFN-α 4MIU/kg for 7days, then received or did not receive i.v. or oral DTX (30mg/kg). Pharmacokinetic studies were done on a part of the mice: DTX concentrations were assessed in plasma and tumors, where AUC were estimated with the Bailer method, and half-lives and MRT were determined with a non-compartmental analysis. Tumor growth was assessed more than 21days: animals were then sacrificed and lung metastases number was counted. Kaplan-Meier analysis was made to analyze survival data during the survey period.

KEY FINDINGS

DTX i.v. associated with IFN-α significantly improved mouse survival (19.6±0.6days vs. 17.1±0.8days for control mice, p=0.047) with greater antimetastatic effects (87.5% reduction in the number of metastases compared to control mice). The effect on tumor growth was not modified within the IFN-α/DTX i.v. treated groups when compared to mice receiving DTX i.v. alone. The pharmacokinetic analysis showed an increase of DTX concentrations in tumors at 30min after DTX i.v. administration and an increase in the oral bioavailability of orally given DTX following an IFN-α treatment.

SIGNIFICANCE

Our study established that IFN-α increases DTX uptake in tumors, improves its antitumoral efficiency and improves animals' survival.

Immunotherapy of cancer in 2012

The immunotherapy of cancer has made significant strides in the past few years due to improved understanding of the underlying principles of tumor biology and immunology. These principles have been critical in the development of immunotherapy in the laboratory and in the implementation of immunotherapy in the clinic. This improved understanding of immunotherapy, enhanced by increased insights into the mechanism of tumor immune response and its evasion by tumors, now permits manipulation of this interaction and elucidates the therapeutic role of immunity in cancer. Also important, this improved understanding of immunotherapy and the mechanisms underlying immunity in cancer has fueled an expanding array of new therapeutic agents for a variety of cancers. Pegylated interferon-α2b as an adjuvant therapy and ipilimumab as therapy for advanced disease, both of which were approved by the United States Food and Drug Administration for melanoma in March 2011, are 2 prime examples of how an increased understanding of the principles of tumor biology and immunology have been translated successfully from the laboratory to the clinical setting. Principles that guide the development and application of immunotherapy include antibodies, cytokines, vaccines, and cellular therapies. The identification and further elucidation of the role of immunotherapy in different tumor types, and the development of strategies for combining immunotherapy with cytotoxic and molecularly targeted agents for future multimodal therapy for cancer will enable even greater progress and ultimately lead to improved outcomes for patients receiving cancer immunotherapy.

Small cell lung cancer: new clinical recommendations and current status of biomarker assessment

Small-cell lung carcinomas (SCLC) represent 15-18% of all lung cancers. As SCLC has a high propensity for early metastatic dissemination, less than a third of patients have limited disease (T0-1N0-3M0). The new TNM classification should now be used also for SCLC. Platin- and etoposide-based chemotherapy is the cornerstone treatment. Response rates to both chemotherapy and radiotherapy are impressive but relapses are frequent. The current state-of-the-art treatment for MO patients involves platin-etoposide-based chemotherapy, combined with early thoracic radiotherapy. Because of the high risk of brain metastases, prophylactic cranial irradiation is indicated in responders and should be part of the standard management. The 5-year survival rate may reach 25% in MO patients, but does not exceed 10% at 2 years in metastatic patients. Most patients relapse within the first two years, and there are few treatment options in second line as opposed to NSCLC. Many issues are subject for further clinical research such as the biology of this disease to better identify pathways that could be targeted with new drugs, optimisation of systemic treatments and radiotherapy. Pursuing clinical trials at all stages constitutes a challenge for thoracic researchers and oncologists.

[Molecular targeted therapies in small-cell lung cancer]

Small-cell lung cancers (SCLC) are aggressive malignancies, however, characterized by high primary chemosensitivity. Unfortunately, for the vast majority of patients, relapse is the rule with emergence of secondary resistance mechanisms. In the era of molecular targeted therapies, characterization of a number of molecular abnormalities has encouraged implementation of several clinical trials. This literature review summarizes the various pharmacological approaches used in SCLC to improve survival in localized and extensive forms of the disease. Initial trials with molecular targeted therapies have not been able to improve clinical outcome compared to the standard etoposide-cisplatin chemotherapy regimen in extensive forms. However, new targets continue to be identified and many treatments are currently being assessed, including blockade of angiogenesis, signal transduction, cell cycle or induction of apoptosis.

The role of interferons in the treatment of osteosarcoma

Interferons, a group of cytokines with antiangiogenic, direct antitumour and immunostimulating properties, have shown significant activity against osteosarcoma in vitro and in xenograft models. They have also been used in osteosarcoma clinical trials as a single adjuvant to surgery, with an apparent increase in relapse-free survival. In the ongoing EURAMOS 1 clinical trial, interferon alpha-2b is evaluated as an adjuvant treatment in osteosarcoma. This article reviews the rationale for the use of interferon in cancer with special reference to the treatment of osteosarcoma, including all published data of clinical efficacy in this disease.

Phase II Study of Vandetanib or Placebo in Small-Cell Lung Cancer Patients After Complete or Partial Response to Induction Chemotherapy With or Without Radiation Therapy: National Cancer Institute of Canada Clinical Trials Group Study BR.20

Purpose

This double-blind randomized phase II trial examined whether vandetanib, an inhibitor of vascular endothelial and epidermal growth factor receptors, could prolong progression-free survival in responding patients with small-cell lung cancer.

Patients and Methods

Eligible patients with complete response (CR) or partial response (PR) to combination chemotherapy (± thoracic or prophylactic cranial radiation) received oral vandetanib 300 mg/d or matched placebo. With 100 patients and 77 events, the study had 80% power to detect an improvement in median progression-free survival from 4 to 6.5 months (one-sided, 10%-level test).

Results

Between May 2003 and March 2006, 107 patients were accrued; 46 had limited disease and 61 extensive disease. There were fewer patients with a performance status of 0 (n = 11 v 20), and fewer had CR to initial therapy (n = 4 v 8) in the vandetanib arm. Vandetanib patients had more toxicity and required more dose modifications for gastrointestinal toxicity and rash. Asymptomatic Corrected QT interval (QTC) prolongation was observed in eight vandetanib patients. Median progression-free survival for vandetanib and placebo was 2.7 and 2.8 months, respectively (hazard ratio [HR], 1.01; 80% CI, 0.75 to 1.36; one-sided P = .51). Overall survival for vandetanib was 10.6 versus 11.9 months for placebo (HR, 1.43; 80% CI, 1.00 to 2.05; one-sided P = 0.9). In planned subgroup analyses, a significant interaction was noted (P = .01): limited-stage vandetanib patients had longer overall survival (HR, 0.45; one-sided P = .07) and extensive-stage vandetanib patients shorter survival compared with placebo (HR, 2.27; one-sided P = .996).

Conclusion

Vandetanib failed to demonstrate efficacy as maintenance therapy for small-cell lung cancer.

Targeted therapies in small-cell lung cancer

Small-cell lung cancer is an aggressive form of lung cancer that, overall, remains the most common cause of cancer death in the US. Some advances have been made in the treatment of small-cell lung cancer using cytotoxic chemotherapeutic agents but no truly targeted therapies are available as of yet. At present, research is focused on finding therapies that can target the specific molecular mechanisms responsible for the survival, growth and metastasis of the tumor thereby improving responses to chemotherapy and minimizing toxicity. Several new agents, such as angiogenesis inhibitors and regulators of apoptosis, have reached clinical testing and multiple others are in preclinical trials. Some of these will be discussed in this review.

Small cell lung cancer and targeted therapies

PURPOSE OF REVIEW

Small cell lung cancer is a chemosensitive malignancy, yet long-term survival remains elusive for the majority of patients. Here, we report on progress in evaluating novel targeted therapies for the treatment of this disease.

RECENT FINDINGS

Interferons, matrix metalloproteinase inhibitors, thalidomide, bevacizumab, ZD6474, imatinib, gefitinib, oblimersen and aplidine have all entered clinical trial in patients with small cell lung cancer. Immunotherapy approaches targeting cell surface antigens such as CD-56 (BB10901) and GD3 ganglioside are also being evaluated. Interferons, matrix metalloproteinase inhibitors, imatinib and gefitinib have failed to demonstrate efficacy for this disease. Preliminary data for thalidomide are promising and so results from trials of other antiangiogenics such as bevacizumab and ZD6474 are awaited with interest.

SUMMARY

Although the promise of targeted therapy has yet to be realized in patients with small cell lung cancer, the number of agents available for evaluation provides new optimism that progress will be made over the next decades.

Phase III study of adjuvant vaccination with Bec2/bacille Calmette-Guerin in responding patients with limited-disease small-cell lung cancer (European Organisation for Research and Treatment of Cancer 08971-08971B; Silva Study)

PURPOSE

Bec2 is an anti-idiotypic antibody that mimics GD3, a ganglioside that is expressed on the surface of tumor cells and is of neuroectodermal origin. We assessed whether Bec2/bacille Calmette-Guerin (BCG) vaccination prolongs survival in patients with limited-disease small-cell lung cancer (SCLC) after a major response to chemotherapy and chest radiation.

PATIENTS AND METHODS

Patients were randomly assigned to receive five vaccinations of Bec2 (2.5 mg)/BCG vaccine or follow-up. Vaccination was given over a 10-week period. The sample size was targeted to detect an increase in median survival of 40% after random assignment, and stratification was by performance status, response, and institution. Quality of life was assessed by using the European Organisation for Research and Treatment of Cancer instrument. Humoral response was assessed in patients who received vaccination.

RESULTS

A total of 515 patients were randomly assigned. The primary toxicities of vaccination were transient skin ulcerations and mild flu-like symptoms. There was no improvement in survival, progression-free survival, or quality of life in the vaccination arm. Median survival from randomization was 16.4 and 14.3 months in the observation and vaccination arms (P = .28), respectively. Among vaccinated patients, a trend toward prolonged survival was observed in those (one third) who developed a humoral response (P = .085). Multivariate analysis showed a positive impact on survival by prior treatment with concomitant chemoradiotherapy, prophylactic cranial irradiation, female sex, low lactate dehydrogenase, and normal platelets.

CONCLUSION

Vaccination with Bec2/BCG has no impact on outcome of patients with limited-disease SCLC responding to combined-modality treatment. Vaccination strategies in SCLC may still be warranted using vaccines that produce a better immunologic response.

Combined Chemoradiotherapy in Small Cell Lung Cancer

Combined chemoradiotherapy is the established standard of care for limited stage small cell lung cancer; it provides cure in 15% to 25% of patients. Early concurrent therapy imparts a 5% long-term survival benefit compared with sequential therapy. Hyperfractionated delivery of radiotherapy may provide a small incremental benefit when compared with standard fractionation. Radiotherapy dose escalation and reduced radiotherapy volumes are feasible; however, survival benefit has not been confirmed. Cisplatin and etoposide remain the preferred chemotherapy agents. New chemotherapeutic agents and novel treatment approaches are under intense investigation.

Novel targeted agents in the treatment of lung cancer

Lung cancer is the leading cause of cancer-related mortality in the US. Although an improvement in outcome is possible with the continued advancement of cytotoxic-based treatment, clinical research is currently focused on utilising novel molecular targets with proven efficacy in preclinical models and a low toxicity profile. This is the result of advances in understanding of tumour biology and molecular pathways that have been implicated in cancer pathogenesis and progression. Novel agents targeting cell cycle regulation, angiogenesis and signal transduction pathways have reached clinical testing in lung cancer and are discussed in this review.

Angiogenesis inhibitors in the treatment of small cell and non-small cell lung cancer

Angiogenesis is believed to play a critical role in cancer; however, antiangiogenic therapy has not been demonstrated to improve the survival of patients who have lung cancer. In this article, the evidence that supports a role for angiogenesis in the pathogenesis of lung cancer, trials of antiangiogenic agents in lung cancer performed to date, and the lessons learned from these studies are discussed.

Progress in the therapy of small cell lung cancer

Small cell lung cancer (SCLC) accounts for approximately 14% of all cases of lung cancer. Combination chemotherapy is the most effective treatment modality for SCLC and recently, several new active drugs have emerged. Combinations of platinum agents with CPT-11 or gemcitabine have been successfully compared in phase III trials against the cisplatin/etoposide standard. Modest improvements in the outcome of patients with SCLC have been noted over the last two decades. Thoracic irradiation given concurrently with chemotherapy improves survival compared with sequential chemotherapy and radiation, but this approach is associated with more toxicity. Moreover, the optimal doses and fractionation of thoracic irradiation remain to be determined. Three-dimensional treatment planning is under investigation. Prophylactic cranial irradiation (PCI) has established a role in the management of patients who have achieved a complete response to the initial therapy. Novel molecular targeted therapies are among the strategies currently being investigated in SCLC.

Recent advances in management of small-cell lung cancer

Small-cell lung cancer (SCLC) is a smoking-related disease with a poor prognosis. While SCLC is usually initially sensitive to chemotherapy and radiotherapy, responses are rarely long lasting. Frustratingly, most patients ultimately relapse, often with increasingly treatment resistant disease. Many strategies have been developed in an attempt to improve treatment outcomes, which have plateaued since the introduction of combination chemotherapy in the 1980s. These include trials of maintenance therapy, and dose intensification, the latter by means of increasing dose density, growth factor support and high dose chemotherapy with autologous stem cell rescue. None have been shown to improve patient survival. On the other hand, the integration of concurrent thoracic radiation and prophylactic cranial irradiation has improved the survival outcomes in patients with limited disease. In extensive disease, irinotecan combined with cisplatin has shown promise in improving survival over conventional platinum/etoposide chemotherapy schedules and a confirmatory study is awaited. The future of SCLC treatment may however lie with molecularly targeted therapies, such as antiangiogenesis agents and signal transduction inhibitors, which are being studied at present.

[Targeted therapies in thoracic oncology]

INTRODUCTION

Better understanding of the alterations of cellular physiology during carcinogenesis has resulted in the development of new anticancer agents called biological targeted therapies. These therapies will probably complement the traditional treatments (surgery, radiotherapy and chemotherapy).

STATE OF THE ART

In thoracic oncology, targeted therapies may interfere with signal transduction by interaction with growth factors receptors. This is the case with monoclonal antibodies directed against the extracellular part of the receptors and with small molecules inhibiting the intracellular part of the receptors (for example, EGF-R).

PERSPECTIVES

Other strategies include the use of farnesyl transferase inhibitors or of antisense oligonucleotides; the new therapies may also inhibit angiogenesis by targeting either the VEGF receptor or the matrix metalloproteases. Inhibitors of metalloproteases were the first targeted agents tested. However, all published studies on metalloproteases inhibitors have been negative so far.

CONCLUSIONS

Currently, the agents most advanced in clinical development are the EGFR inhibitors (either monoclonal antibodies or small molecules inhibiting tyrosine-kinases) which, in those that have clinical activity, may produce a sustained response at a cost of a degree of toxicity.

Targeting angiogenesis: a review of angiogenesis inhibitors in the treatment of lung cancer

It has now been almost 30 years since Dr J. Folkman first proposed that inhibition of angiogenesis could play a key role in treating cancer; however, it is only recently that anti-angiogenesis agents have entered the clinical setting. The search for novel therapies is particularly important in lung cancer, where the majority of patients succumb to their disease despite aggressive treatments. Several classes of agents now exist that target the different steps involved in angiogenesis. These include drugs inhibiting matrix breakdown, the matrix metalloproteinase inhibitors (MMPIs), such as marimastat, prinomastat, BMS275291, BAY12-9566, and neovastat drugs that block endothelial cell signaling via vascular endothelial growth factor (VEGF) and its receptor (VEGFR) including rhuMAb VEGF, SU5416, SU6668, ZD6474, CP-547,632 and ZD4190. Drugs that are similar to endogenous inhibitors of angiogenesis including endostatin, angiostatin and interferons. There has also been renewed interest in thalidomide. Drugs such as squalamine, celecoxib, ZD6126, TNP-470 and those targeting the integrins are also being evaluated in lung cancer. Despite early enthusiasm for many of these agents, Phase III trials have not yet demonstrated significant increases in overall survival and toxicity remains an issue. It is hoped that as our understanding of the complex process of angiogenesis increases, so will our ability to design more effective targeted therapies.

Phase II Trial of Cisplatin/Etoposide and Concurrent Radiotherapy Followed by Paclitaxel/Carboplatin Consolidation for Limited Small-Cell Lung Cancer: Southwest Oncology Group 9713

Purpose

Limited small-cell lung cancer (LSCLC) is characterized by a high initial response rate to chemoradiotherapy, but local or systemic relapse occurs in the majority of patients. Previous Southwest Oncology Group trials in LSCLC have utilized cisplatin and etoposide (PE) delivered concurrently with thoracic radiotherapy followed by two consolidation cycles. Newer chemotherapy regimens such as paclitaxel and carboplatin are active in small-cell lung cancer and hold the promise of improving both local and systemic control. S9713 evaluated the substitution of paclitaxel and carboplatin for PE consolidation in LSCLC.

Patients and Methods

Between July 1998 and August 1999, 96 patients were accrued from 43 institutions. Eighty-nine patients were eligible; 87 were assessable for survival and response. Treatment consisted of cisplatin 50 mg/m2 on days 1, 8, 29, and 36, and etoposide 50 mg/m2 on days 1 to 5 and days 29 to 33, with concurrent radiotherapy of 61 Gy beginning on day 1. Consolidation therapy was carboplatin (area under the curve = 6) and paclitaxel 200 mg/m2, both drugs administered on day 1 of a 21 day cycle for three cycles.

Results

The response rate was 86% (complete response, 33%; partial response, 53%). Median overall survival was 17 months (95% CI, 12.7 to 19.0). One- and 2-year overall survivals were 61% and 33%, respectively. Median progression-free survival (PFS) was 9 months, 1-year PFS was 40%, and 2-year PFS was 21%.

Conclusion

Consolidation therapy with paclitaxel and carboplatin in LSCLC resulted in an outcome similar to that seen in prior Southwest Oncology Group trials. This study and others which have tested paclitaxel in small-cell lung cancer dampens enthusiasm for this agent in the primary management of LSCLC.

Ongoing and future trials of biologic therapies in lung cancer

Lung cancer is the leading world-wide cause of cancer death. The care rate remains less than 15% despite improvements in surgery, radiotherapy and chemotherapy. The majority of deaths can be attributed to systemic metastases. Chemotherapy prolongs survival but produces few complete responses and survival at 5-years is rare. Molecular advances have provided many new targets for lung cancer therapy. Many new agents have been developed to attack these targets. This article describes current and proposed trials for these new targeted therapies in both small cell and non-small cell lung cancers.

Angiogenesis inhibitors under study for the treatment of lung cancer

Several classes of agents now exist that target the different steps involved in angiogenesis. These include drugs inhibiting matrix breakdown, the matrix metalloproteinase inhibitors (MMPIs), such as marimastat, prinomastat, BMS275291, BAY12-9566, and neovastat. Trials of this class of agents have all been negative to date. Drugs that block endothelial cell signaling via vascular endothelial growth factor (VEGF) and its receptor (VEGFR) including rhuMAb VEGF, SU5416, SU6668, ZD6474, CP-547,632 and ZD4190 are all in earlier stages of clinical trial. Drugs that are similar to endogenous inhibitors of angiogenesis including interferons have also been evaluated without success. Endostatin has been shown to have an acceptable toxicity profile, but clinical evidence of activity has not yet been demonstrated. There has also been renewed interest in thalidomide. Drugs such as squalamine, celecoxib, ZD6126, TNP-470 and those targeting the integrins are also being evaluated in lung cancer. Despite early enthusiasm for many of these agents, Phase III trials have not yet demonstrated significant increases in overall survival and toxicity remains an issue. It is hoped that as our understanding of the complex process of angiogenesis increases, so will our ability to design more effective targeted therapies.

Potential of interferon-alpha in solid tumours: part 2

The second part of this review examines the use of recombinant interferon-alpha (rIFNalpha) in the following solid tumours: superficial bladder cancer, Kaposi's sarcoma, head and neck cancer, gastrointestinal cancers, lung cancer, mesothelioma and ovarian, breast and cervical malignancies. In superficial bladder cancer, intravesical rIFNalpha has a promising role as second-line therapy in patients resistant or intolerant to intravesical bacille Calmette-Guérin (BCG). In HIV-associated Kaposi's sarcoma, rIFNalpha is active as monotherapy and in combination with antiretroviral agents, especially in patients with CD4 counts >200/mm(3), no prior opportunistic infections and nonvisceral disease. rIFNalpha has shown encouraging results when used in combination with retinoids in the chemoprevention of head and neck squamous cell cancers. It is effective in the chemoprevention of hepatocellular cancer in hepatitis C-seropositive patients. In neuroendocrine tumours, including carcinoid tumour, low-dosage (</=3 MU) or intermediate-dosage (5 to 10 MU) rIFNalpha is indicated as second-line treatment, either with octreotide or alone in patients resistant to somatostatin analogues. Intracavitary IFNalpha may be useful in malignant pleural effusions from mesothelioma. Similarly, intraperitoneal IFNalpha may have a role in the treatment of minimal residual disease in ovarian cancer. In breast cancer, the only possible role for IFNalpha appears to be intralesional administration for resistant disease. IFNalpha may have a role as a radiosensitising agent for the treatment of cervical cancer; however, this requires confirmation in randomised trials. On the basis of current evidence, the routine use of rIFNalpha is not recommended in the therapy of head and neck squamous cell cancers, upper gastrointestinal tract, colorectal and lung cancers, or mesothelioma. Pegylated IFNalpha (peginterferon-alpha) is an exciting development that offers theoretical advantages of increased efficacy, reduced toxicity and improved compliance. Further data from randomised studies in solid tumours are needed where rIFNalpha has activity, such as neuroendocrine tumours, minimal residual disease in ovarian cancer, and cervical cancer. A better understanding of the biological mechanisms that determine response to rIFNalpha is needed. Studies of IFNalpha-stimulated gene expression, which are now feasible, should help to identify molecular predictors of response and allow us to target therapy more selectively to patients with solid tumours responsive to IFNalpha.

Interferon trials in small cell lung cancer at one institution: a comparison of results obtained before and after initiation of systematic treatment trials using IFN-alpha in combination with other modalities

Chemotherapy became the primary treatment for small cell lung cancer (SCLC) in the early 1970s. The standard drug combinations were first vincristine, adriamycin, and cyclophosphamide (VAC) and then, from the early 1980s, etoposide-platinum combinations. Despite a good initial objective response, however, patients usually suffer a rapid relapse. Treatment development has, therefore, focused on ways to overcome drug resistance, and on the addition of cytokines to the chemotherapeutic arsenal. Interferon (IFN) was one of the first cytokines found to have anticancer effects, and it was introduced into the combined modality regimens used to treat SCLC in the early 1980s in an attempt to overcome the problem of early relapse. The role of IFN was investigated with the aim of establishing how best to combine it with other treatments for SCLC. In this paper, we review the impact of IFN on the outcome for 714 SCLC patients who were treated in randomized IFN trials at one institution over a period of 20 years and IFN trials conducted at other institutions during the same period. The parameters we used at our institution to measure outcome tended to improve during the period when patients were being treated in our three randomized IFN trials, compared with the period when patients received only standard treatment in a nonclinical trial setting. However, the differences were not statistically significant. During this period, IFN was used as maintenance therapy, concomitantly with chemotherapy, and combined with other treatment modalities. Our experience is that IFN-alpha is most effective when administered as low-dose maintenance treatment. Other IFN trials published during the same period were small and heterogeneous. Results were inconsistent and added little new information, although it has been shown that high pretreatment levels of serum vascular endothelial growth factor (VEGF) predict a poor response to treatment and consequently a poor outcome. The recently confirmed antiangiogenic properties of IFN deserve to be investigated in studies of maintenance treatment, in combination with other biologic agents. Patient should be selected according to criteria based on pretreatment assessment of biologic markers, such as VEGF and basic fibroblast growth factor (bFGF). Our studies, all at one institution, pioneered the biologic treatment of solid tumors and developed a solid basis of knowledge for future studies of biologic agents in cancer treatment.

Angiogenesis inhibitors in the treatment of lung cancer

Numerous inhibitors of angiogenesis are currently under study in lung cancer. Four trials of adjuvant interferon after chemotherapy for small cell lung cancer (SCLC) were negative. Several metalloproteinase inhibitors (MMPIs) are now in study in SCLC and non-small cell lung cancer (NSCLC). Two large randomized trials have closed recently in which Marimastat 10 mg bid was compared to placebo in responding patients with SCLC. Two randomized studies of Prinomastat versus placebo with combination chemotherapy in advanced NSCLC have also completed accrual. The results of these trials are not yet available, but should be reported in mid-2001. A Phase III trial of BMS-275291, a broad-spectrum MMPI in combination with paclitaxel and carboplatin is open for patients with advanced NSCLC. Neovastat, a standardized shark cartilage extract is under study in inoperable Stage III NSCLC. VEG-F gene expression is increased in many tumors including NSCLC, and may act as a paracrine mediator of growth. A randomized Phase II trial of paclitaxel and carboplatin with or without a recombinant humanized anti-VEG-F has been undertaken in NSCLC. Modestly better response and survival were seen with anti-VEG-F and a large Phase III trial is planned. Numerous receptor tyrosine kinases (TK) have been found to be directly or indirectly involved in angiogenesis including Flk-1, Flt-l, Tie-1 and Tie-2. SU5416 is a small molecular TK inhibitor and potent inhibitor of VEG-F-mediated Flk-1 receptor signaling. Another TK inhibitor SU6668 blocks VEG-F, bFGF and PDGF receptor signaling. It is orally available, and it may be evaluated in lung cancer trials in the near future. ZD4190 is an inhibitor of KDR/Flk-1 that may be evaluated in SCLC. Thalidomide has recently been shown in pre-clinical models to be anti-angiogenic. A randomized trial of paclitaxel/carboplatin and radiation with or without thalidomide is open for patients with Stage IIIB NSCLC in the United States. Numerous other anti-angiogenesis agents are in early clinical trials, but have not been evaluated in lung cancer yet.

Treatment of extensive stage small cell lung cancer

Over the past twenty years combination chemotherapy has continued to produce small survival gains for patients with SCLC. We enter the next century enthusiastic about the array of new chemotherapeutic agents to evaluate and fascinated by the biological agents with the hope of achieving dramatic improvements in survival for our patients with SCLC.

Interferon-alpha and 13-cis-retinoic acid as maintenance therapy after high-dose combination chemotherapy with growth factor support for small cell lung cancer--a feasibility study

This randomized phase II multi-center study was designed to determine the time to progression, duration of response and the feasibility of an intensified maintenance regime consisting of a combination of interferon (IFN)-alpha and retinoic acid after high-dose combination chemotherapy and radiotherapy in patients with small cell lung cancer. The patients received four courses of combination chemotherapy consisting of ifosfamide, carboplatin and etoposide, with higher doses of ifosfamide and carboplatin given in the first course, with routine growth factor support. Responding patients were then randomly assigned to one of three maintenance therapy arms. All patients with limited disease (LD) were given thoracic radiotherapy before maintenance therapy and those who had also achieved a complete response (CR) or minimal residual disease (MRD) received prophylactic cranial irradiation. In Arm 1 patients received IFN-alpha-2a, 6 MIU s.c. TIW for 4 weeks, followed by 3 MIU s.c. TIW, and 13-cis-retinoic acid 1 mg/kg/day p.o. BID daily. In Arm 2 patients received trophosphamide 100-150 mg/day p.o. BID. No maintenance treatment was given in Arm 3, the control group. Maintenance therapy was continued for 1 year. Eighty-five patients were treated according to the protocol. Twenty-one patients achieved CR, four achieved MRD and forty-two achieved partial responses to chemotherapy and radiotherapy. Sixty patients (71%) were randomly assigned for maintenance treatment. Median survival was 17.1 months in the IFN-alpha-retinoic acid arm, 12.4 months in the trophosphamide arm and 13.5 months in the control arm. One-year survival rates were 82, 56 and 55%, respectively. Duration of response was 6.5, 5.5 and 4.7 months, respectively. Time to progression was 8.6, 8.0 and 6.8 months, respectively The differences were not statistically significant. The IFN-alpha-retinoic acid maintenance treatment was well tolerated. Patients who received IFN-alpha-retinoid maintenance therapy lived longer after the onset of progressive disease. The treatment regime was effective, feasible and well tolerated.

Acute-phase proteins and hematologic values in ovine lentivirus-infected lambs treated with recombinant ovine IFN-tau

To evaluate changes in complete blood cell (CBC) counts, haptoglobin and fibrinogen in ovine lentivirus (OvLV)-infected lambs treated with recombinant ovine interferon-tau (rOVIFN-tau), 24 lambs were allocated to one of four groups (n = 6 per group): (1) virus + rOvIFN-tau, VI, (2) virus + placebo, VP, (3) no virus + rOVIFN-tau, NVI, and (4) no virus + placebo, NVP. Three lambs in each group were treated once a day for 12 weeks, and the remaining 3 lambs were treated for 33 weeks. Blood was collected at days 0, 7, and 10 and at weeks 2-10, 12, 32, and 33 to determine CBC counts, as well as haptoglobin and fibrinogen levels. Hematologic values remained within normal limits in all groups. However, hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and packed cell volume (PCV) values decreased (p < 0.05) in the two rOvIFN-tau-treated groups (VI and NVI) compared with the placebo-treated (VP and NVP) groups. Both rOvIFN-upsilon and OvLV had a mild negative effect on neutrophil numbers. Although Hb, MCV, MCHC, PCV, and neutrophil values declined in the rOvIFN-tau-treated lambs compared with the placebo-treated lambs, these values remained within the reference range for sheep. Experimental lambs did not show adverse clinical signs associated with OvLV infection or as a result of rOvIFN-tau treatment. The lack of significant side effects of high-dose rOvIFN-tau in sheep and previous reports of broad-spectrum and cross-species antiviral activity suggest that rOvIFN-tau warrants further investigation as an antiviral therapeutic agent.

Concomitant chemotherapy and IFN-alpha for small cell lung cancer: a randomized multicenter phase III study

Patients with any stage of small cell lung cancer were given low-dose interferon-alpha (IFN-alpha) from the first day of treatment as long as possible irrespective of changes in treatment dictated by disease progression. All patients received 6 cycles of the chemotherapy (CT): cisplatin 70 mg/m2 i.v. day 1 and etoposide 100 mg/m2 i.v. days 1, 2, 3 every 28 days. Seventy-eight patients were assigned to arm 1: CT alone, 75 patients to arm 2: CT + natural IFN-alpha (3 MU three times a week i.m.), and 66 patients to arm 3: CT + recombinant IFN alpha-2a (3 MU three times a week i.m.). There was no difference in median survival between the arms (10.2 months, 10.0 months, 10.1 months, respectively), p = 0.32. The 2-year survival rates were 15%, 3%, and 11%, respectively. Grade 3 and 4 leukopenia occurred more frequently in the IFN arms than in the CT alone arm and resulted in dose reductions. Antibodies occasionally developed to recombinant IFN. We conclude that IFN-alpha can be administered concomitantly with chemotherapy but is probably better kept for maintenance therapy so that optimal full doses of induction CT can be given.

Immunotherapy in lung cancer

More research and new treatment options are needed in all stages of lung cancer. To this end immunotherapy needs a revival in view of recent improved technologies and greater understanding of the underlying biology. In this review we discuss mechanisms of tumour immunotherapy, non-specific, specific and adoptive, with particular reference to a direct therapeutic action on all subtypes of lung cancer.