Objective This exploratory analysis evaluated the incidence of adverse events (AEs) by folate receptor (FR) status in the randomized, multicenter, open-label PRECEDENT study in women with platinum-resistant ovarian cancer receiving pegylated liposomal doxorubicin (PLD) ± the small-molecule drug conjugate vintafolide.

Methods Women 18 years or older with platinum-resistant ovarian cancer were randomized 2:1 to vintafolide (2.5 mg intravenously, 3 times per week, weeks 1 and 3, every 28 days) + PLD (50 mg/m² intravenously, day 1, every 28 days) or PLD alone (same dose/schedule). The expression of functionally active FR was evaluated by single-photon emission computed tomography with etarfolatide. Patients were categorized according to FR positivity: patients with all target lesions positive for FR expression (FR 100%), patients with 1 or more but not all target lesions positive for FR expression (FR 10%–90%), and patients with all lesions negative for FR expression (FR 0%).

Results Data on FR status were available for 94 patients: 38 were FR 100%, 36 were FR 10% to 90%, and 20 were FR 0%. Across all FR subgroups, the duration of treatment was longer, and the number of cycles was higher in combination-therapy arms than PLD-alone arms. Although the frequency of AEs was relatively consistent across subgroups, the FR 100% subgroup had a higher incidence of patients with at least 1 AE for combination therapy versus PLD alone. No surprising safety signals were shown according to FR status. The incidence of grade 3 or 4 treatment-emergent drug-related AEs was generally low across all FR subgroups and treatment arms.

Conclusions This exploratory analysis suggests that FR status does not influence the AE profile of vintafolide + PLD combination therapy or PLD alone in patients with platinum-resistant ovarian cancer. Future a priori analyses in larger populations are needed to confirm these findings.