Maintenance therapy using sunitinib improved progression-free survival (PFS) among patients with extensive-stage small-cell lung cancer participating in a phase II clinical trial, investigators reported online March 3 in Journal of Clinical Oncology.
The proactive maintenance approach proved to be significantly less toxic than waiting for disease progression and then giving the same dose of sunitinib, which provides a strong rationale for investigating maintenance therapies in general for patients with extensive-stage small cell lung cancer (SCLC). In addition, since sunitinib inhibits multiple targets of interest in SCLC (including tyrosine kinase, vascular endothelial growth factor receptors, platelet-derived growth factor receptors, Flt-3, and Kit), the study findings also suggest that other multitarget inhibitors should be assessed as treatments for SCLC, said Dr. Neal E. Ready of Duke University Medical Center, Durham, N.C., and his associates.
In their study, 95 patients who had stable disease, partial response, or compete response to standard initial chemotherapy were randomly assigned in a double-blind fashion to receive either sunitinib or placebo as maintenance therapy until SCLC progressed. A total of 85 of these patients received at least one dose as assigned: 44 received sunitinib and 41 received placebo.
The main efficacy outcome – median PFS – was 3.7 months for sunitinib and 2.1 months for placebo, a significant difference. Three patients taking sunitinib achieved a complete response, compared with none taking placebo, the investigators said (J. Clin. Oncol. 2015 March 3 [doi:10.1200/jco.2014.57.3105]).
In addition, 13 patients who were initially assigned to placebo showed disease progression and were permitted to cross over to sunitinib. Ten of them (77%) attained prolonged disease control, including three (23%) who achieved complete response. This demonstrates a major therapeutic benefit for a small subset of patients who have rapidly growing refractory SCLC, Dr. Ready and his associates said.
The most frequent adverse events were fatigue (19% of patients taking sunitinib and 10% of those taking placebo), decreased neutrophils (14% on sunitinib), decreased leukocytes (7% on sunitinib), and decreased platelets (7% on sunitinib). The most serious (grade 4) adverse events were one case each of GI hemorrhage, pancreatitis, hypocalcemia, and elevated lipase among patients taking sunitinib and hypernatremia in a patient taking placebo.