NBTS, aligned with the National Cancer Institute, is helping to support research of Dr. Andrew Parsa.
One of the most important missions of the National Brain Tumor Society (NBTS) is to identify – and support – biomedical research that has the potential to cure or slow the development of brain tumors.
A neurological surgeon who has been aided by federal and patient-advocacy funding, Andrew T. Parsa, MD, PhD, of the University of California, San Francisco, is encouraged by early and preliminary results from his study to evaluate overall survival in patients in a project that offers a "vaccine" to battle brain tumors.
"Although it is quite early in the study," Dr. Parsa said in a progress report, "we are very encouraged by the fact that to date we have seen no progression in any patients including two patients approaching one year after diagnosis with GBM (gliobastoma)."
The research of Dr. Parsa has been supported by the National Cancer Institute, through its Specialized Programs of Research Excellence (SPORE) initiative. The NBTS and other advocacy groups provided funding once the research was started. The combining of resources of NCI, NBTS, ABTA and ABC2 and the laboratory of Dr. Parsa signifies collaboration at the highest level.
Dr. Parsa’s approach is to prepare a patient’s immune system to combat the extremely aggressive, persistent cancer the same way a vaccine helps the body fight the flu. After Dr. Parsa removes the tumor, he has a vaccine created from proteins specific to that tumor plus a ferrying compound, called a heat-shock protein, and injects it back into the patient over the course of four weeks. This prepares the immune system to produce fighter white blood cells, called T cells that find and kill any new cancerous cells with proteins matching those extracted from the tumor.
The trial was initiated in June 2009 and patients are eligible if they have pathological confirmation of GBM, undergo gross total resection of the tumor and receive standard of care XRT and TMZ, per the Stupp protocol. (Patients are ineligible if they progress during standard of care treatment, prior to the initiation of vaccine therapy.)
His current Phase 2 trial is a single-arm, open-label study designed to evaluate overall survival in patients treated with the autologous, tumor-derived, heat shock protein peptide-complex vaccine HSPPC-96, injected intradermally once weekly for four consecutive weeks and monthly thereafter with maintenance temozolomide.
Dr. Parsa says currently 26 patients have been screened and five patients have been treated to date (four patients are pending vaccine therapy). The doctor stated that immunomonitoring thus far is consistent with results of his recurrent glioma vaccine trial, suggesting an antitumor immune response. In Parsa’s first study, in 2008, 12 vaccinated patients went on to live an average of 10 months longer after diagnosis of a recurrent tumor.
The support of NBTS and other advocacy groups has been essential, Dr. Parsa says. "Simply put, this trial would not have gotten off the ground without the patient advocacy support."
"We are pleased to be working together with such talented and dedicated laboratory researchers, clinical research doctors, and committed health-care leaders,” said David R. Hurwitz, PhD, the Richard B. Ross chief scientific officer of NBTS. “We are hopeful that this valuable work will make a difference."
A challenge that doctors face in the development of new therapies for brain tumors is that the body’s blood-brain barrier, which is designed to shield the brain from harmful chemicals, actually blocks most drug therapies from reaching brain tumor cells. Thus most chemotherapeutic drugs, including chemotherapeutics and drugs that inhibit specific cellular targets, are not effective in combating this type of cancer.
"We need alternative treatments, using the immune system," says Dr. Parsa. "Just like the vaccine we give for measles, mumps and the flu, the idea is to prevent cancer from coming back after surgery."
In a statement on his website, Dr. Parsa says he is collaborating with a biotechnology company, Antigenics Inc., to develop the vaccine. He said that early indications are that the vaccine seems safe and well-tolerated by patients, causing few or no side effects.
"We are hopeful that Dr. Parsa’s research will make a positive difference for patients, their families and the medical community," said N. Paul TonThat, executive director of NBTS.