AST-VAC1 is an autologous (patient-specific) cancer vaccine designed to stimulate patients’ immune system to attack telomerase, a protein that is expressed in over 95 percent of cancers but is rarely expressed in normal adult cells. We are developing AST-VAC1 for the treatment of Acute Myeloid Leukemia (AML), the most common form of acute leukemia in adults. Treatments for AML are typically performed in two phases: an initial “induction” phase targeted at bringing patients into remission, followed by “consolidation” therapy to eliminate minimal residual disease and hopefully maintain remission. Many therapies are in development for AML induction therapy.
There is a significant unmet clinical need, especially in unfavorable risk patients and those over the age of 60 (who frequently do not tolerate current consolidation therapies), , for consolidation therapies that can maintain long term remissions with an acceptable tolerability profile. AST-VAC1 has the potential to supplement current and pipeline treatment regimens in order to improve long-term remission for these patients.
AST-VAC1 was previously tested in a multi-center, open-label, Phase 2 clinical trial in patients with intermediate and high risk AML. Primary objectives and endpoints were the feasibility of manufacture of AST-VAC1, along with the safety and tolerability of the vaccine in patients with AML in complete remission at screening. Long term follow up of Phase 2 clinical results [link to ASCO presentation] demonstrated that 57% of patients over 60 years of age receiving AST-VAC1 were still in complete remission at 52 months. This compares very favorably to historical data from multiple sources indicating 4 year relapse-free survival rates of 10-20% in this population.
The AST-VAC1 treatment is well tolerated with safety established through both phase 1 and phase 2 trials. The phase 1 study of metastatic prostate cancer patients found no major treatment related toxicities or any autoimmune pathology. In the phase 2 trial of AML patients, there was only one significant adverse event deemed possibly related to treatment.
We are currently performing process development of our AST-VAC1 manufacturing process in preparation for a confirmatory Phase 2b study designed to reproduce these results in a larger, randomized trial.