Allos Therapeutics, Inc. said an independent Data Monitoring Committee (DMC) has completed the pre-specified 65-patient safety review of data from the company's pivotal phase II PROPEL trial of PDX (pralatrexate) in patients with relapsed or refractory peripheral T-cell lymphoma (PTCL). The committee has also recommended the trial to continue as per the protocol.

This interim assessment was based upon an evaluation of patients enrolled in the study who completed at least one cycle of treatment with PDX. The company currently expects to complete patient enrolment in the PROPEL study in the second quarter of 2008.

"The DMC recommendation represents another important milestone in the development of a potential new treatment option for patients with relapsed or refractory peripheral T-cell lymphoma, a patient population for which there are currently no approved agents," said Pablo J. Cagnoni, M.D., senior vice president and chief medical officer, Allos. "We remain pleased with the progress of the PROPEL trial and look forward to continuing to drive our PDX product development and commercialisation plans in 2008."

PROPEL (Pralatrexate in Patients with Relapsed Or Refractory PEripheral T-cell Lymphoma) is a pivotal phase II, international, multi-centre, open-label, single-arm study that will seek to enrol a minimum of 100 evaluable patients with relapsed or refractory PTCL who have progressed after at least one prior treatment.

In accordance with the PROPEL study design, in January 2007, the DMC completed an interim analysis of safety data based on the first 10 patients enrolled to the study who completed at least one cycle of treatment with PDX, and recommended that the trial continue per the protocol. Also in accordance with the study design, in September 2007, an interim analysis of patient response and safety data was conducted based on the first 35 patients enrolled to the study who completed at least one cycle of treatment with PDX. The results of the interim analysis of patient response data exceeded the pre-specified threshold for continuation of the trial, which required a minimum of four responses (complete or partial) out of the first 35 evaluable patients, as determined by independent oncology review. In addition, the DMC identified no major safety concerns and recommended that the trial continue per the protocol.

The PROPEL trial is being conducted under an agreement with the United States Food and Drug Administration (FDA) under its special protocol assessment (SPA) process. The SPA process allows for FDA evaluation of a clinical trial protocol intended to form the primary basis of an efficacy claim in support of an NDA, and provides an agreement that the study design, including trial size, clinical endpoints and/or data analyses are acceptable to the FDA.

The DMC is comprised of independent medical experts and was established by Allos as part of the company's compliance with good clinical practice guidelines. The DMC is responsible for monitoring the on-going safety of patients participating in the PROPEL trial and for conducting formal interim safety assessments of trial results.

Peripheral T-cell lymphomas, or PTCLs, are a biologically diverse and uncommon group of blood cancers that account for approximately 10 per cent to 15 per cent of all cases of non-Hodgkin's lymphoma, or about 7,100 patients annually. The average five-year survival rate for PTCL patients is approximately 25 per cent. There are currently no pharmaceutical agents approved for use in the treatment of either first-line or relapsed or refractory PTCL.

PDX is a novel, small molecule chemotherapeutic agent that inhibits dihydrofolate reductase, or DHFR, a folic acid (folate)-dependent enzyme involved in the building of nucleic acid, or DNA, and other processes. PDX was rationally designed for efficient transport into tumour cells via the reduced folate carrier, or RFC-1, and effective intracellular drug retention.