Preliminary results of a pivotal Phase 2 clinical trial of pralatrexate (PDX), a drug that partially works by mimicking folic acid, showed a complete or partial response in 27 percent of patients with recurrent or resistant peripheral T-cell lymphoma (PTCL).
PROPEL (Pralatrexate in patients with Relapsed Or refractory PEripheral T-cell Lymphoma) findings were presented by the study's principal investigator, Dr. Owen A. O'Connor of the Herbert Irving Comprehensive Cancer Center at Columbia University Medical Center and NewYork-Presbyterian Hospital, at the 50th Annual Meeting of the American Society of Hematology (ASH) in San Francisco.
The international, multicenter PROPEL trial is the largest ever conducted in patients with peripheral T-cell lymphoma -- a biologically diverse group of blood cancers that account for as many as 15 percent of non-Hodgkin's lymphoma (NHL) cases in the United States. There are currently no pharmaceutical agents approved for use in the treatment of either first-line or relapsed or refractory PTCL, and average five-year survival is approximately 25 percent.
"These results indicate that pralatrexate produces a major durable response in patients for whom numerous prior treatments have been unsuccessful," says Dr. Owen A. O'Connor, director of the Lymphoid Development and Malignancy Program and chief of the Lymphoma Service at the Herbert Irving Comprehensive Cancer Center at NewYork-Presbyterian Hospital and Columbia University Medical Center, and associate professor of medicine at Columbia University College of Physicians and Surgeons.
Prior to enrolling in the trial, eligible patients had received a median of three (range of 1 to 12) prior systemic treatment regimens, including 16 percent of patients who had previously undergone an autologous stem cell transplant.
"Presently, there are no FDA-approved drugs for patients with PTCL, whether it is in the front-line or for patients with relapsed or refractory disease. This underscores the need for new therapies to treat this challenging disease. Pralatrexate has the potential to play a clinically meaningful role in the treatment of these patients," adds Dr. O'Connor. Pralatrexate, designed to look like the natural vitamin folic acid, disrupts DNA synthesis in tumor cells. The drug is designed to selectively accumulate in tumor cells, after which it then induces programmed cell death, or apoptosis, in the cancer cell.
A total of 109 evaluable patients received 30 mg/m2 of pralatrexate intravenously once every week for six weeks followed by one week of rest per cycle of treatment. Patients also received vitamin B12 and folic acid supplementation. Response was assessed using standard International Workshop Criteria (IWC).