894PPRECEDENT SUBSET ANALYSIS: SAFETY AND DISEASE CONTROL WITH VINTAFOLIDE MONOTHERAPY FOLLOWING DISCONTINUATION OF PEGYLATED LIPOSOMAL DOXORUBICIN (PLD)

ABSTRACT Aim: Differential expression of the folate receptor (FR) in normal (low) and malignant (high) tissues makes FRs promising therapeutic targets. The randomized phase II PRECEDENT trial (NCT00722592) comparing vintafolide (Vinta), a folic-acid/desacetylvinblastine conjugate, and PLD vs PLD alone in platinum-resistant ovarian cancer (PROC) patients (pts) demonstrated progression-free survival (PFS) benefit in the combination arm (5.0 vs 2.7 months, respectively) and etarfolatide could predict Vinta responders (Naumann et al, JCO. 2013;31:4400). This subset analysis evaluated safety and disease control in pts who discontinued PLD and continued on single-agent Vinta. Methods: PROC pts (≥18 years) with ECOG PS of 0-2 and Results: The intention-to-treat population was 149 pts (Vinta + PLD, n = 100; PLD, n = 49). Twenty-two pts from the combination arm discontinued PLD and continued on Vinta alone. The most common reasons for PLD discontinuation were maximum permitted dose (n = 6) and hand-foot syndrome (n = 9). Median number of cycles of Vinta alone was 4 (range: 1-16). In pts receiving only Vinta, median time from monotherapy to progression, death, or treatment discontinuation was 4.3 months, and median survival time was 18 months. Treatment toxicity in these 22 pts was less during treatment with Vinta alone, compared with the Vinta + PLD combination, for the following (respectively): gastrointestinal disorders (9.1% vs 95.5%); skin or soft tissue disorders (9.1% vs 90.9%); hematologic disorders (9.1% vs 77.3%). Conclusions: Following discontinuation of PLD, Vinta monotherapy resulted in continued disease control with a favorable side-effect profile. These data indicate a potential benefit of continued Vinta monotherapy for patients unable to continue on the Vinta + PLD combination. Disclosure: R. Clark: Other substantive relationships: Employee of Endocyte; R.T. Penson: Scientific Advisory Board Member: Endocyte Corporate-sponsored research: Clinical Trial Funding - PI for Endocyte. All other authors have declared no conflicts of interest.