MimiVax’s cancer vaccine failed to meet the primary endpoint in a phase 2b trial in newly diagnosed glioblastoma, but the biotech says results in patients 65 and younger still offer a path forward for the candidate.
The Buffalo, New York-based company tested SurVaxM, a peptide-mimic immunotherapeutic vaccine, against placebo in 233 evaluable patients, with both arms also receiving standard care. Median overall survival (OS) was 22.8 months in the SurVaxM group and 20.3 months in the placebo group, a difference that fell short of statistical significance (p=0.076).
In an Oct. 7 announcement, MimiVax called the improvement “clinically meaningful” while acknowledging that the study missed its primary endpoint.
Survival gains in patients 65 and younger
The biotech instead pointed to a prespecified subgroup of patients aged 65 and younger. In that group, median OS was 24.2 months with SurVaxM versus 20.2 months with placebo (p=0.019), which MimiVax described as “a significant benefit.”
The subgroup also fared better on progression-free survival: 44% of SurVaxM recipients were progression-free at 12 months, compared with 24% of those on placebo. About 42% of SurVaxM-treated patients in this age group were alive at 30 months or later, versus 18% on placebo, and the company reported no further deaths among them between 30 and 54 months.
Despite the top-line miss, MimiVax said the subgroup results give it confidence to pursue an eventual FDA approval. The company plans to request a meeting with the agency in the coming months to agree on a path forward.
High unmet need in glioblastoma
“Even very small increases in survival are very significant to the patients, taking into perspective that there hasn’t been a new GBM drug in over 20 years,” MimiVax CEO Michael Ciesielski, Ph.D., said.
“For these patients there’s no choice at all,” he continued. “There is nothing else to give them, and any improvement is great.”
Glioblastoma is the most common and most aggressive brain tumor in adults. Even with the best available treatment, most patients die within about 18 months of diagnosis. The tumors have multiple ways of evading therapy, which makes them notoriously hard to treat, and the field has seen little progress since the chemotherapy temozolomide was introduced in 2005.
“There’s been so many trials that have been tried and failed in between that there just hasn’t been anything in such a long time for these patients,” Ciesielski said. “It’s great to see something finally moving the needle in this disease.”
How the vaccine works
SurVaxM targets survivin, a protein that blocks programmed cell death and can make tumor cells resistant to conventional therapies. The vaccine is designed to train the immune system to recognize and attack cells that express survivin, which is found in roughly 95% of glioblastoma tumors and in many other cancers, Ciesielski said.
“What we wanted was something that was highly expressed and easy to be accessible to the immune system – this fit the bill,” the CEO said.
The phase 2b study follows an open-label phase 2a trial, completed in 2022, in which patients receiving SurVaxM with adjuvant temozolomide had a median OS of 25.9 months.
In the latest trial, patients received four priming doses of SurVaxM two weeks apart, followed by booster shots every two months. This came on top of standard care: surgery to remove as much of the tumor as possible, plus chemotherapy and radiation.
On safety, the most common side effects were grade 1 and 2 injection site reactions. Grade 3 or higher adverse events occurred in 48% of patients in the SurVaxM group and 46% in the placebo group.
A crowded, difficult field
MimiVax was founded in 2012 as a spinoff of Roswell Park Comprehensive Cancer Center in Buffalo. Beyond glioblastoma, the biotech is running mid-stage trials of its cancer vaccines in metastatic neuroendocrine tumors and multiple myeloma, and plans to launch a study of a preventive lung cancer vaccine soon.
Other companies chasing new approaches to glioblastoma have had mixed results. Imvax’s autologous cell immunotherapy, a drug-device combination, failed a phase 2b study at the end of last year. Evaxion is developing an off-the-shelf therapeutic vaccine for glioblastoma, while BrainChild Bio is targeting pediatric brain cancer with a triple-targeting CAR-T therapy that is expected to enter the clinic next year in partnership with Duke University.
MimiVax’s Brain Cancer Vaccine Misses Phase 2b Goal
MimiVax’s investigational cancer vaccine, SurVaxM, has missed the primary endpoint in a Phase 2b clinical trial for newly diagnosed glioblastoma, an aggressive form of brain cancer. However, the company believes the findings among patients aged 65 and younger could offer a path forward for further development.
Announced on October 7, 2026, the results came from the SURVIVE trial, which compared SurVaxM with a placebo in 233 evaluable patients. The study measured overall survival, an important indicator of how long patients live after treatment.
Younger Patients Show a Stronger Survival Signal
Despite the overall trial result, MimiVax highlighted findings from a prespecified subgroup of patients aged 65 and younger. In this group, median overall survival reached 24.2 months with SurVaxM, compared with 20.2 months in the placebo group. The difference was statistically significant.
The younger subgroup also showed encouraging progression-free survival results. At 12 months, 44% of patients receiving SurVaxM remained progression-free, compared with 24% of those receiving placebo. Additionally, approximately 42% of SurVaxM-treated patients in this age group were alive at 30 months or longer, compared with 18% in the placebo group.
These findings may help guide future research, but subgroup results do not erase the missed primary endpoint. Further evaluation will be needed to understand the vaccine’s potential benefits and identify which patients may be most likely to respond.
How SurVaxM Works
MimiVax’s SurVaxM is an investigational immunotherapy vaccine designed to target survivin, a protein commonly expressed in glioblastoma cells. The treatment aims to stimulate the immune system to recognize and attack cancer cells expressing this protein.
The vaccine was studied alongside standard treatment, including surgery, radiation therapy and chemotherapy. Safety findings indicated that adverse events were mainly mild or moderate injection-site reactions, although serious adverse events were also reported in both study groups.
MimiVax’sNext Steps Toward Potential FDA Review
MimiVax plans to discuss the Phase 2b findings with the U.S. Food and Drug Administration (FDA), including possible regulatory pathways and whether further confirmatory research may be required. The company has emphasized the survival findings among younger patients as a reason to continue evaluating SurVaxM.
However, SurVaxM remains investigational and is not FDA-approved. Additional regulatory discussions and clinical evidence will be important before its potential availability can be determined.
The results illustrate the challenges of developing treatments for glioblastoma, where effective options remain limited. For MimiVax, the next stage will involve determining whether the promising findings in younger patients can support a credible path toward further development.MimiVax’s investigational brain cancer vaccine, SurVaxM, has missed the primary endpoint in its Phase 2b clinical trial for newly diagnosed glioblastoma, but MimiVax’s leadership believes the results among younger patients offer a potential path forward. Although MimiVax’s vaccine did not demonstrate a statistically significant improvement in overall survival across the full study population, MimiVax’s findings showed encouraging survival outcomes in patients aged 65 and younger. MimiVax’s SurVaxM achieved a median overall survival of 24.2 months in this subgroup, compared with 20.2 months for patients receiving placebo.
These results could help shape MimiVax’s future discussions with the FDA about further development and possible regulatory options. However, MimiVax’s vaccine remains investigational, and additional evidence may be needed to confirm its potential benefits. Despite missing the main trial goal, MimiVax’s team continues to evaluate whether the younger-patient findings can support the next stage of brain cancer research.
Glioblastoma is one of the most aggressive forms of brain cancer, and treatment remains challenging despite advances in medical research. Standard care often includes surgery, radiation therapy, and chemotherapy, but the disease frequently returns after initial treatment.
How SurVaxM Works
MimiVax is developing SurVaxM as an investigational cancer vaccine designed to target survivin, a protein associated with cancer cell survival. The treatment aims to stimulate the immune system to recognize and attack tumor cells, potentially offering another approach to glioblastoma treatment.
Why the Younger-Patient Results Matter
The Phase 2b trial showed more encouraging survival outcomes among patients aged 65 and younger than in the overall study population. These findings could help researchers investigate whether age or other patient characteristics influence treatment response. However, further research is needed to establish whether the observed benefit is consistent and clinically meaningful.
MimiVax’s Next Steps
MimiVax may pursue discussions with the FDA to understand the regulatory options available for SurVaxM. The next steps could include additional analyses, further clinical studies, or other evidence requested by regulators. The missed primary endpoint remains an important limitation, and the younger-patient findings alone do not establish that the vaccine is effective.
The Outlook for Brain Cancer Research
The results illustrate the difficulty of developing new therapies for glioblastoma, where treatment options remain limited. Continued investigation could help clarify whether SurVaxM has a role in treating specific patient groups. For now, MimiVax’s vaccine remains investigational, and its future will depend on additional clinical evidence and regulatory review.
