Purpose

Development of new therapies for previously treated small-cell lung cancer (SCLC) is a major unmet need. Here, we describe a randomized, phase II trial of weekly topotecan with or without ziv-aflibercept (VEGF-trap) in this clinical setting.

Patients and methods

Patients with previously treated SCLC (one line of platinum-based chemotherapy), performance status of 0 to 1, adequate organ function, treated brain metastases, and no recent vascular events or bleeding diatheses were eligible. Eligible patients were stratified as platinum-sensitive or platinum-refractory and randomly assigned to receive weekly topotecan 4 mg/m(2) intravenously (IV) with or without ziv-aflibercept 6 mg/kg IV every 21 days. Progression-free survival (PFS) at 3 months was the primary end point.

Results

In 189 randomly assigned patients, treatment arms were well balanced with regard to clinical characteristics. The 3-month PFS was significantly improved with the addition of ziv-aflibercept in patients who had platinum-refractory disease (27% v 10%; P = .02) but not in patients with platinum-sensitive disease (24% v 15%; P = .22). Although response rate was low, disease control rate was higher with combination therapy than with topotecan alone in patients who had platinum-sensitive disease (37% v 18%; P = .05) and in those who had platinum-refractory disease (25% v 15%; P = .14). Overall survival (OS) was not significantly improved in either strata. Grades 3 to 5 toxicities were more common with the addition of ziv-aflibercept.

Conclusion

Ziv-aflibercept improved the 3-month PFS in patients who had platinum-refractory SCLC, but its addition increased toxicity. OS was similar with combined ziv-aflibercept and topotecan compared with topotecan in both strata.

Background

Extensive-stage small-cell lung cancer (SCLC) patients who progress after platinum-based chemotherapy are traditionally categorized as platinum sensitive (progression ≥ 90 days from last platinum dose) or refractory (progression < 90 days), a practice arising from seminal observations of worse survival in refractory patients. Subsequent trials accounted for platinum sensitivity, resulting in higher sample sizes and increased resource use.

Methods

To assess whether platinum-sensitivity status remains associated with outcomes, patient-level data from recent Southwest Oncology Group trials in second- and/or third-line extensive-stage SCLC were pooled. Hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS) accounting for platinum sensitivity were calculated using unadjusted and adjusted Cox Proportional Hazard models. Recursive partitioning was performed to define prognostic risk groups.

Results

Of 329 patients, 151 were platinum sensitive and 178 refractory. HRs from unadjusted Cox PFS and OS models for refractory versus sensitive disease were 1.0 (95% confidence interval, 0.81-1.25; p = 0.98) and 1.24 (0.99-1.57; p = 0.06), respectively. Adjusted Cox models showed that only elevated serum lactate dehydrogenase (HR, 2.04; p < 0.001), males (HR, 1.36; p = 0.04), performance status of 1 (HR, 1.25; p = 0.02), and weight loss greater than or equal to 5% (1.53, p = 0.01) were independently associated with OS. Platinum-sensitivity status was not associated with PFS (HR, 1.11; p = 0.49) or OS (HR, 1.25; p = 0.14), except in a model that excluded 36 patients who received more than one prior chemotherapy regimen (HR, 1.34; p = 0.049). Prognostic groups with differential OS outcomes (high, intermediate, and poor risk) were identified.

Conclusions

Platinum-sensitivity status may no longer be strongly associated with PFS or OS in at least one multivariate model. Validation of prognostic risk groups identified here is warranted. These data have critical implications in the design of future SCLC trials.