Vaxiion Therapeutics has completed the dose escalation phase of its Phase 1 study for VAX014, a novel bacterial minicell-based oncolytic immunotherapy, and initiated a Phase 1b dose expansion study combining the treatment with established PD-1 checkpoint inhibitors. The San Diego-based biotechnology company announced that VAX014 demonstrated good tolerability and immune-mediated antitumor activity in heavily pretreated solid tumor patients.
Phase 1a Results Show Promise for Novel Approach
The dose escalation segment enrolled 18 heavily pretreated solid tumor patients across five dose levels. The study design evolved during the trial, with the first nine patients receiving injections in a single tumor with fixed dose volume, while the subsequent nine patients were allowed to have multiple tumors injected. Across all dose levels, VAX014 was well tolerated as monotherapy and provided strong evidence of immune-mediated antitumor activity in both injected and non-injected tumors.
VAX014 represents a first-in-class, pan-tumor targeted oncolytic immunotherapy using bacterial minicells, specifically designed for optimal activity in STING and/or RIG-I positive tumors. This design addresses a key biological limitation of oncolytic virus-based therapies. The treatment is provided as a sterile product that eliminates the need for BSL-2 biocontainment, dramatically increasing patient access compared to oncolytic viruses.
Phase 1b Expansion Targets Checkpoint Inhibitor Resistance
The Phase 1b dose expansion study (NCT05901285) is now open and enrolling at eight sites across the United States. The study utilizes an adaptive trial design to evaluate the safety and efficacy of VAX014 in combination with investigator's choice of pembrolizumab or nivolumab in patients with solid tumors that have progressed after prior PD-1 directed immune checkpoint blockade.
Based on current enrollment rates, Vaxiion anticipates enrolling up to 30 patients in the next 12 months. The combination approach builds on the hypothesis that VAX014 facilitates development of robust antitumor T cell responses to potentiate the effectiveness of immune checkpoint blockade.
Clinical Investigator Perspectives
"The monotherapy data with VAX014 is promising and I am eager to see how it performs in combination with pembrolizumab or nivolumab," said study Principal Investigator Dr. Elizabeth Buchbinder of the Dana-Farber Cancer Institute. "Having a locally administered oncolytic immunotherapy option that doesn't require special handling and biocontainment considerations has been really nice."
Vaxiion CEO Matt Giacalone expressed optimism about the program's progress: "We are happy to report the initiation of the dose expansion segment of this ongoing study and are encouraged by the safety and efficacy data as well as the positive investigator and patient feedback from the dose escalation study."
Platform Technology Advantages
Vaxiion's bacterial minicell-based delivery platform offers several advantages over traditional oncolytic virus approaches. The elimination of BSL-2 biocontainment requirements significantly improves practical implementation in clinical settings, while the targeting of STING and RIG-I pathways addresses known limitations in viral oncolytic therapies.
The company is leveraging its proprietary first-in-class bacterial minicell-based delivery platforms to develop novel, next-generation oncology products beyond VAX014.
