An investigational immunotherapeutic vaccine called rindopepimut appears promising in the treatment of glioblastoma mutiforme (GBM). These Phase II clinical trial results were recently presented at the 2010 annual meeting of the Society for Neuro-Oncology.
Glioblastoma mutiforme is one of the most common and fatal types of primary brain cancer. It develops from the glial cells, which are the most abundant cells in the nervous system. Glial cells provide supportive functions that facilitate the work of neurons (cells that transmit impulses between the brain, spinal column, and nerves). Current treatment for GBM includes surgery followed by radiation and chemotherapy with Temodar® (temozolomide). However, even with the most aggressive treatment available, many patients will survive less than one year after diagnosis. As such, researchers continue to evaluate new and innovative treatment strategies.
Rindopepimut is an investigational cancer vaccine that is designed to stimulate the immune system to attack targets found on cancer cells. This particular vaccine targets the epidermal growth factor receptor variant III, or EGFRvIII. It is estimated that 25-30% of GBM patients have EGFRvIII-positive disease.
The multicenter ACT III trial evaluated rindopepimut in combination with radiation plus Temodar in patients with newly diagnosed GBM that expressed EGFRvIII. Sixty-five patients were enrolled in this Phase II study. Tumors had been surgically removed in all patients. For each participant, vaccination with rindopepimut began three months after diagnosis.
- Progression-free survival at 8.5 months was 66%, which exceeded the estimated PFS of 53%. A PFS of 66% also exceeds the expected PFS rate for patients receiving the standard of care (radiation plus Temodar) for GBM as well PFS rates from historical data.
- Rindopepimut also appeared active in patients whether or not they had an active DNA repair gene (MGMT)—this is significant because MGMT may limit the effectiveness of treatment with radiation plus Temodar.
- Rindopepimut in combination with radiation plus Temodar was well tolerated. The most common side effects were local reactions at the injection site.
“These data suggest that rindopepimut is extending survival well beyond what we have seen historically in this patient population,” a lead investigator on the study concluded. Evaluation of rindopepimut will continue in a Phase III trial, which researchers say may begin in 2011.
Reference: Lai R, Recht LD, Reardon DA et al. Final analysis of ACT III: a phase II trial of PF-04948568 (CDX-110) in combination with temozolomide (TMZ) in patients (pts) with newly diagnosed glioblastoma (GBM). Presented at the 2010 annual meeting of the Society for Neuro-Oncology. Montreal, Quebec, Canada. November 18-21, 2010. Abstract OT-31.