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Antiangiogenesis in Small-Cell Lung Cancer: Is There a Path Forward?

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Tiseo M, Boni L, Ambrosio F, et al. Italian, multicenter, phase III, randomized study of cisplatin plus etoposide with or without bevacizumab as first-line treatment in extensive-disease small-cell lung cancer: the GOIRC-AIFA FARM6PMFJM Trial. J Clin Oncol 2017;35:1281–7.

 

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Study Overview

Objective. To evaluate efficacy of adding bevacizumab to first-line chemotherapy for treatment of extensive-disease small-cell lung cancer (ED-SCLC).

Design. Phase III prospective multicenter randomized clinical trial.

Setting and participants. The study was conducted at 29 Italian centers and was supported by the Agenzia Italiana del Farmaco. Study entry was limited to patients with histologically or cytologically documented ED-SCLC who were previously untreated with systemic therapy, were 18 years of age or older, and had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 to 2. Adequate bone marrow, renal, and liver functions were required. Patients with asymptomatic, treated brain metastases were eligible for trial participation. Exclusions included the following: mixed histologic diagnosis of SCLC and non–SCLC; history of grade 2 hemoptysis; evidence of lung tumor cavitation; significant traumatic injury within the 4 weeks before first dose of study treatment; other active malignancies (previous or current); and any underlying medical condition that might be aggravated by treatment.

Intervention. Patients received a combination of intravenous cisplatin (25 mg/m2 on days 1 to 3), etoposide (100 mg/m2 on days 1 to 3), and bevacizumab (7.5 mg/kg intravenously on day 1) administered every 3 weeks (experimental arm); or the same cisplatin and etoposide chemotherapy regimen alone given every 3 weeks (control arm). Carboplatin (area under the curve 5 on day 1) could be substituted for cisplatin in case of cisplatin contraindications or cisplatin-associated toxicity. Tumor response, on the basis of investigator-assessed Response Evaluation Criteria in Solid Tumors (RECIST; version 1.1), was evaluated every 3 cycles during chemotherapy treatment. After 6 cycles of chemotherapy, tumor assessment was performed every 9 weeks in both arms. In the absence of progression, patients in the treatment arm continued bevacizumab alone until disease progression or for a maximum of 18 courses. Survival follow-up information was collected every 6 months after treatment termination or last dose of study drug, until death or loss to follow-up.

Main outcome measure. The primary end point was overall survival (OS). Response rate, toxicity, and progression-free survival (PFS) were secondary end points.

Main results. 205 patients were randomized between November 2009 and October 2015. 204 patients were considered in the intent-to-treat analysis (103 in the control arm and 101 in the treatment arm). Most patients were male with ECOG PS of 0 to 1. Median age was 64 years. The median number of chemotherapy courses administered was 6 in both arms. Cisplatin was used in majority of the patients. Average relative dose intensities for all drugs were well balanced between 2 groups. A lower percentage of patients in the treatment arm (14.7%) than in the control arm (22.3%) discontinued treatment because of radiologic disease progression, which was the main reason for treatment discontinuation.

At a median follow-up of 34.9 months, the median PFS was 5.7 in the control arm and 6.7 months in the treatment arm (hazard ratio [HR], 0.72; 95% CI, 0.54 to 0.97; P = 0.30). Median OS times were 8.9 months and 9.8 months, and 1-year survival rates were 25% and 37% (HR, 0.78; 95% CI, 0.58 to 1.06; P = 0.113) in the control arm and treatment arm, respectively. A significant effect of the maintenance treatment on OS (HR, 0.60; 95% CI, 0.40 to 0.91, P = 0.011) was observed. A subgroup analysis revealed a statistically significant interaction for OS between treatment and sex; the addition of bevacizumab led to a significant survival benefit in men (HR, 0.55) and to a possible detrimental effect in women (HR, 1.55; interaction test, P = 0.003).

Addition of bevacizumab did not result in increase in hematologic toxicity such as anemia, neutropenia, or thrombocytopenia. Concerning the nonhematologic toxicity, only hypertension was more frequent in the bevacizumab arm (6.3%) compared to chemotherapy alone arm (1%). The rates of proteinuria and thrombosis were similar in both arms.

Conclusion. The addition of bevacizumab to cisplatin and etoposide in the first-line treatment of ED-SCLC had an acceptable toxicity profile and led to a statistically significant improvement in PFS, which, however, did not translate into a statistically significant increase in OS.

 

Commentary

SCLC currently accounts for approximately 12% to 15% of all lung cancers [1]. It is characterized by a rapid growth rate, metastasis at the time of diagnosis, sensitivity to first-line platinum-based chemotherapy, and invariable recurrence and progressive resistance to subsequent lines of therapy. A number of clinical trials over the past 2 decades have failed to produce outcomes superior to platinum-based doublet chemotherapy, leaving a significant unmet need [2]. Vascular endothelial growth factor (VEGF) is the most important proangiogenic factor, and it is implicated in tumor growth [3]. Bevacizumab, a humanized monoclonal antibody directed against VEGF, is now indicated in the treatment of several tumor types including non–SCLC and breast, colorectal, kidney, and ovarian cancer. Positive signal with bevacizumab was seen in phase II studies, providing rationale for this phase III trial [4,5] .

The study by Tiseo and colleagues reported the outcomes of a randomized study that added bevacizumab to standard combination therapy with platinum and etoposide for the treatment of ED-SCLC. A small statistically significant improvement was seen in PFS (6.7 months vs. 5.7 months, favoring the bevacizumab group). However, the study failed to meet the primary end point of improved OS.

So where do antiangiogenesis agents go from here? Alternative angiogenesis inhibitors with broader mechanism of action are being explored in clinical trials. One such trial (ClinicalTrials.gov identifier: NCT02945852) is evaluating the role of the tyrosine kinase inhibitor apatinib in combination with chemotherapy in ED-SCLC. Apatinib selectively inhibits the vascular growth factor receptor-2 (VEGFR2). In addition, this agent also inhibits c-kit and c-SRC tyrosine kinase. It would be interesting to see if antiangiogenic agents with broader mechanisms would be more effective in SCLC. Immunotherapy with checkpoint inhibitors such as nivolumab and pembrolizumab have revolutionized the lung cancer treatment paradigm. It would be interesting to see if bevacizumab could be safely added to these immunotherapy agents. The ongoing CheckMate 370 (ClinicalTrials.gov identifier: NCT02574078) is addressing this question, evaluating the safety of combining nivolumab with bevacizumab in non-SCLC.

 

Applications for Clinical Practice

The current study does not support the addition of bevacizumab as a standard therapeutic option in the first-line treatment of ED-SCLC. However, given that there was a trend towards improved OS, alternative strategies of incorporating antiangiogenesis agents should be considered in future clinical trials.

—Deval Rajyaguru, MD

References

1. Neal JW, Gubens MA, Wakelee HA. Current management of small cell lung cancer. Clin Chest Med 2011;32:853–63.

2. Bunn PA Jr, Minna JD, Augustyn A, et al. Small cell lung cancer. Can recent advances in biology and molecular biology be translated into improved outcomes? J Thorac Oncol 2016;11:453–74.

3. Ferrara N, Gerber HP, LeCouter J. The biology of VEGF and its receptors. Nat Med 2003:9:669–676.

4. Horn L, Dahlberg SE, Sandler AB, et al. Phase II study of cisplatin plus etoposide and bevacizumab for previously untreated, extensive-stage small-cell lung cancer: Eastern Cooperative Oncology Group Study E3501. J Clin Oncol 2009;27:6006–11.

5. Spigel DR, Townley PM, Waterhouse DM, et al. Randomized phase II study of bevacizumab in combination with chemotherapy in previously untreated extensive-stage small-cell lung cancer: Results from the SALUTE trial. J Clin Oncol 2011;29:2215–22.

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