Researchers from Duke University have reported promising results for the administration of 131 I-labeled murine antitenascin monoclonal antibody 81C6 (131I-81C6) into the surgical resection cavity of patients with newly diagnosed glioblastoma multiforme (GBM) or anaplastic astrocytoma when given with external beam radiotherapy and temozoloide (Temodar®). The details of this pilot study appeared in an early online publication on February 20, 2008 in Neuro-Oncology.

Glioblastoma multiforme is one of the most common and fatal types of primary brain cancer. Patients with GBM typically have a poor prognosis, and treatment is usually palliative. The standard initial treatment for patients with GBM is surgery followed by radiation therapy. Historically, chemotherapy has had little impact on outcomes. Recently, a large Phase III multi-national study carried out by the European Organization for Research and Treatment of Cancer (EORTC) and the National Cancer Institute of Canada (NCIC) have reported that patients with GBM who received concurrent and adjuvant Temodar in addition to radiation lived significantly longer than those who received radiation therapy alone. However, only half of the patients receiving Temodar benefited, and this population of responders could be identified by DNA testing of tumor samples. French researchers have reported that Temodar and BiCNU® (carmustine) used prior to and following radiation therapy is a promising regimen in patients diagnosed with inoperable GBM. Researchers from Germany have also reported promising results treating newly diagnosed patients with GBM with Temodar, CeeNU (lomustine), and radiation therapy.

Researchers in the current study evaluated a monoclonal antibody that was combined with a radioactive 131 I, which allowed radiation to be applied directly to the tumor site following surgical removal of the tumor. In addition, traditional external radiation was used as well as chemotherapy. Participants included 16 patients with GBM and five with anaplastic astrocytoma. Twenty patients received the monoclonal antibody, radiation, and chemotherapy regimen. Side effects were mild and limited to low white blood cell and platelet counts, wound infections, and headaches.

The following was reported after an average follow-up of 151 weeks:

• The average survival time for all patients was 96 weeks.
• Among patients with GBM, average survival was 90 weeks.
• At one year 87% of the GBM patients were still alive.

Researchers were encouraged by the overall survival results of the treatment strategy as well as by the tolerability of the combined regimen. A randomized trial will compare the current regimen of 131 I-81C6, external beam radiotherapy, and Temodar with the standard regimen of Temodar and external beam radiotherapy.

Comments: This is a novel approach to the delivery of increased doses of local radiation therapy and it will be of interest to see if the Phase I-II data are confirmed in a Phase III study.

Related News:

Radiotherapy for Glioblastoma in the Elderly is Effective Palliation (4/19/2007)

Temodar®, CeeNU® and Radiation Therapy Promising for Glioblastoma (9/25/2006)

Reference: Reardon, D., Zalutsky, M., Akabani, G., et al. A Pilot Study: 131 I-Antitenascin monoclonal antibody 81c6 to deliver a 44Gy resection cavity boost. Neuro-Oncology. 2008; DOI:10.1215/15228517-2007-053.