Ovarian Cancer Drug Vintafolide Fails Phase III Trial
Treatment has no effect on progression-free survival
Merck and Endocyte, Inc. have announced that the data safety monitoring board (DSMB) of the PROCEED trial has recommended that the study be stopped because vintafolide, an investigational folate small-molecule drug conjugate (SMDC), did not demonstrate efficacy on the prespecified outcome of progression-free survival (PFS) in women with platinum-resistant ovarian cancer.
Based on the DSMB’s recommendation, the two companies have notified investigators that screening and randomization of participants in the study will be suspended.
PROCEED was a phase III, randomized, double-blind trial evaluating vintafolide in combination with pegylated liposomal doxorubicin (PLD) compared with PLD plus placebo for the treatment of folate receptor-positive, platinum-resistant ovarian cancer. The study’s primary endpoint was PFS, as measured by RECIST (Response Evaluation Criteria in Solid Tumor) v 1.1 criteria in patients with all target tumor lesions positive, as assessed by the etarfolatide imaging agent.
In October 2013, Merck reported positive results from the phase II PRECEDENT trial of vintafolide plus PLD compared with PLD alone in women with platinum-resistant ovarian cancer.
Median PFS was 5.0 months for vintafolide plus PLD compared with 2.7 months for PLD alone (hazard ratio [HR], 0.63; P = 0.031) in the intent-to-treat population. Patients with folate receptor-positive tumors demonstrated greater benefit, as measured by PFS, from treatment with vintafolide plus PLD versus PLD alone. The median PFS benefit in these patients was 5.5 months compared with 1.5 months for PLD alone (HR, 0.38; P = 0.013).
Vintafolide is an investigational, injectable, folate SMDC consisting of folate (vitamin B9) linked to a vinca alkaloid chemotherapy agent, desacetylvinblastine hydrazide. Vintafolide is designed to target the chemotherapy agent to rapidly growing cancer cells, which take up folate via the folate receptor. The folate receptor is expressed in a wide variety of cancers, including ovarian cancer.
Etarfolatide is an investigational folate receptor-targeted companion diagnostic imaging agent that is being developed as a noninvasive method to identify tumors that express the folate receptor. These tumors are the molecular target of folate receptor-targeted therapeutic compounds, such as vintafolide.