36 Prognostic value and association with veliparib benefit of modeled CA-125 elimination kinetics (KELIM) in patients with newly diagnosed ovarian cancer: analysis from the VELIA/GOG-3005 study

Introduction

In VELIA (Phase 3), veliparib with carboplatin/paclitaxel (CP), followed by veliparib maintenance (veliparib-throughout) led to improved progression-free survival (PFS) vs CP alone (control). This exploratory analysis assessed the prognostic and predictive value of the modeled CA-125 elimination rate constant, KELIM.

Methods

KELIM was estimated from treatment-related pharmacodynamic modeling of CA-125 values. Median KELIM was used to define favourable (≥median)/unfavourable (<median) KELIM groups. Patients were analyzed by surgery type: primary (PDS) or interval (IDS) debulking surgery.

Results

In the IDS population (N=154), patients with favourable KELIM had a higher frequency of complete surgery vs unfavourable KELIM (51.9% vs 32.4%), confirming KELIM as a chemosensitivity marker. In both PDS (N=700) and IDS populations, median PFS was longer with favourable KELIM vs unfavourable KELIM, demonstrating a prognostic value. In the PDS population, median PFS was longer in the veliparib-throughout arm relative to control irrespective of KELIM (29.6 vs. 20.9 and 18.2 vs 15.4 months in favourable and unfavourable KELIM groups, respectively; figure 1). In the IDS population, median PFS was longer with veliparib-throughout vs control for patients with favourable KELIM only (29.3 vs 20.8 months; figure 2).

Conclusion

In VELIA, KELIM was prognostic for PFS and IDS outcomes. Current data suggest KELIM may be associated with veliparib benefit. Ongoing analyses will explore how baseline characteristics contribute to KELIM predictive/prognostic value.