An experimental vaccine designed to prevent the recurrence of glioblastoma, one of the deadliest forms of brain cancer, has demonstrated promising results in early clinical trials, extending average survival time to 26 months compared to the typical 12-18 month prognosis.
The vaccine, called SurVaxM, targets survivin, a protein found in 95% of glioblastomas that plays a crucial role in cancer cell survival. Developed by New York-based MimiVax, the treatment works by training the immune system to recognize and attack cancer cells, potentially preventing tumor recurrence after initial treatment.
Clinical Trial Results Show Encouraging Survival Rates
In a recent clinical trial involving 63 newly diagnosed glioblastoma patients, SurVaxM demonstrated significant survival benefits. According to trial data, 51% of participants survived at least two years, and 41% survived three years following treatment. These results represent a substantial improvement over the current five-year survival rate of 6.8% for glioblastoma patients.
"This could bring hope to people who are impacted by GBM," said Honggang Cui, an associate professor of chemical and biomolecular engineering at Johns Hopkins Whiting School of Engineering.
The success story of John Wishman, a 61-year-old Buffalo resident diagnosed with glioblastoma in fall 2020, illustrates the vaccine's potential. Two and a half years after his diagnosis, Wishman continues to travel and enjoy life, attributing his extended survival to the experimental vaccine he received through an expanded access program.
Addressing Treatment Challenges in Glioblastoma
Glioblastoma presents unique treatment challenges due to its aggressive nature and growth patterns. As many as 12,000-14,000 new cases are diagnosed annually in the United States, accounting for almost half of all malignant brain tumors.
"It's like octopus tentacles reaching into other parts of the brain," explained Cui, describing why surgical removal of the entire tumor is almost impossible. The cancer's invasive growth pattern means that unless every cancer cell is eliminated, tumors often recur.
Current treatment typically involves surgery, chemotherapy with temozolomide, and radiation therapy. However, targeted therapies like checkpoint inhibitors, which have shown success in other cancers, are less effective for brain tumors because they cannot cross the blood-brain barrier.
Vaccine Administration and Trial Design
The SurVaxM vaccine is administered as an injection in the arm, similar to flu or COVID-19 vaccines. The treatment protocol consists of four initial doses spread over two months, followed by booster doses every two months.
Dr. Robert Fenstermaker, chair of the neurosurgery department at Roswell Park Comprehensive Cancer Center and co-creator of SurVaxM, explained the timing: "There's usually a hiatus of about a month while radiation is still working, and it's during that phase that we like to start the vaccination because that's when the immune system has been rejuvenated."
Expanding Clinical Research
MimiVax is now conducting a larger Phase 2b trial enrolling up to 270 patients across more than 10 sites in the United States and China. This randomized, double-blinded study will compare the vaccine to standard care, with participants receiving either the active vaccine or a placebo.
Tracey Kassman, a 65-year-old retired lawyer from Buffalo who enrolled in the trial in April 2022, described her experience: "It's been at times a leap of faith, because right before I get the shot, I have this MRI, and every time I have the MRI, I'm like, 'OK, well this could be it.'"
The company expects earliest results from the Phase 2b trial by mid-2024, with trial completion anticipated 18-24 months later. If successful, a larger Phase 3 clinical trial will be required before potential regulatory approval.
Safety Profile and Future Applications
According to Fenstermaker, the vaccine has demonstrated a favorable safety profile. Known side effects include fever, itching, redness, and muscle aches. Michael Ciesielski, CEO of MimiVax, noted that the company is also investigating SurVaxM's potential in treating other cancers, including multiple myeloma and neuroendocrine tumors.
The vaccine's mechanism of targeting survivin, a protein present in many cancer types, suggests broader therapeutic applications beyond glioblastoma.
Patient Perspectives on Clinical Trial Participation
Katy Sanchez, who was diagnosed with glioblastoma at age 28 and participated in the Cleveland Clinic trial five years ago, has experienced no disease progression since receiving SurVaxM. She continues to receive the vaccine every ten weeks and undergo MRI monitoring.
"I think you've got to give yourself time for a little bit of grief. This is not anything you ever expect to happen in your life. While there may not be a lot of treatments, there are a growing number of clinical trials. And that gives me hope," Sanchez shared.
Dr. Alyx Porter, a neuro-oncologist at the Mayo Clinic in Phoenix who is not involved with the SurVaxM trial, emphasized the importance of exploring new approaches: "The high mortality rates of glioblastoma warrants people pressing the edge and seeking out new treatments and allowing us to really maximize where immunotherapy may benefit."
