Maintaining therapeutic activity in the operating room: compatibility of a gamma-retroviral replicating vector with clinical materials and biofluids
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Updated: Apr 11, 2026
Production of Replication-Defective Retrovirus by Transient Transfection of 293T cells
Published on: December 4, 2007
Ryan Burnett1, Carlos E Ibañez1, Pär L Pettersson1
1Tocagen Inc., Bunker Hill St. , San Diego, CA, USA.
Abstract:
Toca 511 is a novel retroviral replicating vector, encoding a modified yeast cytosine deaminase, administered to recurrent high grade glioma patients in Phase 1 trials by stereotactic, transcranial injection into the tumor or into the walls of the resection cavity. A key issue, with little published data, is vector biocompatibility with agents likely to be encountered in a neurosurgical setting. We tested biocompatibility of Toca 511 with: delivery devices; MRI contrast agents, including ProHance supporting coinjection for real time MRI-guided intratumoral delivery; hemostatic agents; biofluids (blood and cerebrospinal fluid); potential adjuvants; and a needleless vial adapter that reduces risk of accidental needle sticks. Toca 511 is stable upon thawing at ambient temperature for at least 6 hours, allowing sufficient time for administration, and its viability is not reduced in the presence of: stainless steel and silica-based delivery devices; the potential MRI contrast agent, Feraheme; ProHance at several concentrations; the hemostatic agent SURGIFOAM; blood; cerebrospinal fluid; and the needleless vial adapter. Toca 511 is not compatible with the hemostatic agent SURGICEL or with extended exposures to titanium-based biopsy needles.
Insights
Toca 511, a novel cancer therapy vector, demonstrates good biocompatibility with common neurosurgical materials and fluids. It is stable for administration but incompatible with specific hemostatic agents and biopsy needles.
Area of Science:
- Oncolytic Virotherapy
- Biocompatibility Studies
- Neurosurgery
Background:
- Toca 511 is a retroviral replicating vector encoding cytosine deaminase for high-grade glioma treatment.
- Phase 1 trials involve stereotactic injection into tumors or resection cavities.
- Vector biocompatibility with neurosurgical agents is crucial but understudied.
Purpose of the Study:
- To assess the biocompatibility of Toca 511 with materials and agents used in neurosurgery.
- To determine Toca 511 stability and viability in the presence of various substances.
Main Methods:
- Toca 511 was tested for stability and viability against delivery devices, MRI contrast agents (ProHance, Feraheme), hemostatic agents (SURGIFOAM, SURGICEL), biofluids (blood, CSF), and a needleless vial adapter.
- Coinjection compatibility with ProHance for MRI-guided delivery was evaluated.
- Compatibility with titanium biopsy needles was also assessed.
Main Results:
- Toca 511 remained stable for at least 6 hours post-thawing.
- Viability was unaffected by stainless steel/silica devices, Feraheme, ProHance, SURGIFOAM, blood, CSF, and the vial adapter.
- Toca 511 showed incompatibility with SURGICEL and prolonged exposure to titanium biopsy needles.
Conclusions:
- Toca 511 exhibits favorable biocompatibility with most tested neurosurgical materials and biofluids, supporting its clinical use.
- Careful selection of hemostatic agents and biopsy needles is necessary to ensure vector integrity during administration.
