Phase 1/2 clinical trial data of Oncophage for recurrent high-grade glioma

May 20 2010

Antigenics (NASDAQ: AGEN) today announced that data from a multi-center Phase 1/2 clinical trial of Oncophage (vitespen) for recurrent high-grade glioma (brain cancer) was presented at the International Conference on Brain Tumor Research and Therapy. The study was conducted by the Brain Tumor Research Center at the University of California, San Francisco (UCSF).

“Furthermore, I am encouraged that recurrent glioma patients treated with Oncophage are experiencing longer than anticipated survival without treatment-related toxicities. These data could potentially justify advancement into late-stage trials.”

Data from 32 evaluable patients suggest that vaccination with Oncophage may improve overall survival in patients with recurrent high-grade glioma. An overall median survival of 44 weeks after tumor resection was observed. Approximately 70% of the evaluable patients survived beyond 36 weeks, and 41% survived up to or longer than one year. This is considered a significant achievement in the treatment of recurrent high-grade glioma. In addition, Oncophage was well tolerated, with no serious adverse events attributable to the vaccine.

All patients tested to date exhibited a significant innate immune response following vaccine administration. Furthermore, the majority of these patients showed an adaptive immune response, demonstrated by significant increases in CD8 and CD4 T cell responses. An innate immune response is defined as a generalized response, whereas the adaptive immune response is tumor antigen-specific. Taken together, these immune responses have the potential to kill tumor cells and may lead to patient benefit.

"The results from this trial suggest clear biological activity associated with Oncophage treatment as evidenced by stimulation of robust immune responses in the patients evaluated to date," said Andrew T. Parsa, MD, PhD, associate professor in the department of neurological surgery at UCSF, and principal investigator of the trial, who presented the update. "Furthermore, I am encouraged that recurrent glioma patients treated with Oncophage are experiencing longer than anticipated survival without treatment-related toxicities. These data could potentially justify advancement into late-stage trials."

In a separate, more recently initiated Phase 2 trial enrolling patients with newly diagnosed glioma>® (Merck: temozolomide), a chemotherapeutic that is the current standard of care. Clinical and immunologic evaluation is ongoing.

Study Details

The Phase 2 portion of the recurrent high-grade glioma trial is designed to enroll approximately 50 patients. The overall goal of this investigator-initiated, multi-center, single-arm, open-label study is to evaluate median overall survival, progression-free survival and immunologic response to vaccine treatment. Patients undergo surgery to remove their tumors, which are then used to manufacture their patient-specific vaccines. Patients receive four weekly doses of Oncophage and then bi-weekly doses thereafter in the absence of disease progression, unacceptable toxicity, or vaccine depletion. To date, side effects observed in this study have been minor and have included injection-site reaction, fatigue, and headaches. The trial is supported in part through a grant from the National Institutes of Health. Last year, the trial was expanded to include New York-Presbyterian Hospital/Columbia University Medical Center and the Brain Tumor and Neuro-Oncology Center at University Hospitals Case Medical Center.

The Phase 2 newly diagnosed glioma trial is designed to enroll about 60 patients. This single-arm, open-label, investigator-initiated trial is designed to evaluate median overall survival, progression-free survival and immunologic response to vaccine treatment. Patients undergo surgery to remove their tumors, which are then used to manufacture their patient-specific vaccines. According to the protocol, patients receive Temodar concurrently with Oncophage once weekly for four consecutive weeks and monthly until vaccine depletion. The trial is supported through a grant from the American Brain Tumor Association and the National Cancer Institute Special Programs of Research Excellence.

Antigenics will assess data from the glioma trials as it matures and is currently assessing potential product registration strategies for Oncophage in this indication in the US and other territories.