(ChemotherapyAdvisor) – Erythropoietin stimulating agents (ESA) and granulocyte colony stimulating factor (G-CSF) do not affect overall survival (OS) rates among patients with ovarian cancer who receive bevacizumab plus chemotherapy — but ESA is associated with a significantly-elevated risk of venous thrombotic events (VTE), according to a multicenter Gynecologic Oncology Group study published in Gynecologic Oncology.

“Neither ESA nor G-CSF had a negative impact on survival after adjustment of prognostic factors among patients with ovarian cancer receiving chemotherapy,” reported lead author Frederick B. Stehman, MD, at the Indiana University School of Medicine in Indianapolis, and coauthors. “ESA may appear to be associated with shorter survival in univariate analyses because factors prognostic for ESA use are also prognostic for progression-free survival.”

The authors cautioned against prophylactic administration of ESA, however, and recommended ESA be used “with caution” for treating chemotherapy-associated anemia among patients with ovarian cancer, because of an increased risk of VTE in this patient population.

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Nor did ESAs or G-CSF appreciably modulate bevacizumab’s effects on patient survival, the authors noted.

The study included 1,864 women with ovarian cancer, enrolled in a protocol to assess bevacizumab plus chemotherapy during 2005 to 2009; 428 (22.9%) received an ESA and 498 (26.7%) women received G-CSF. The median age of patients was 60.0 years (1st and 3rd quartiles 52.4 and 67.0, respectively), the authors reported.   

Median OS at 5 months after initiation of treatment was 34 months among women receiving ESA vs. 38 months among women not receiving ESA (multivariate HR 0.989 [95% confidence interval: 0.849–1.15]) and 40 months among those receiving G-CSF versus 37 months for those who did not (multivariate HR 0.932 [95% CI: 0.800–1.08]).

ESA was associated with a 3-fold increase in VTE.

“CTCAE grade 3 or higher VTE occurred more often among those treated with an ESA (9 of 428 (2.1%) versus 10 of 1436 (0.7%); P<0.020)” for G-CSF, the authors wrote. “While the absolute risk of a serious thrombotic event is small, after adjusting for treatment with bevacizumab, the risk was three times greater among those treated with ESA (relative odds 3.31 [95% CI: 1.15-9.52]).”

Study coauthor Dr. James T. Thigpen disclosed that he is a speaker/consultant for Amgen, Jansen Biotech, and Genentech; coauthor Dr. Robert Burger has participated in advisory board meetings for Roche/Genentech.