Frequently Asked Questions

Q: What is Toca 511?
A: Toca 511 is an investigational biologic drug composed of a retroviral replicating vector (virus) containing a cytosine deaminase (CD) gene.

Q: What is Toca FC?
A: Toca FC is an investigational extended-release oral drug containing 5-FC (flucytosine). It is intended to be used in combination with, and after administration of, Toca 511.

Q: What is Toca 511 & Toca FC?
A: Toca 511 & Toca FC is an investigational combination treatment that is designed to deliver high amounts of a cancer killing drug to the cancer tissue while leaving healthy tissue unharmed. In preclinical brain cancer studies in animals, Toca 511 & 5-FC (the active ingredient in Toca FC) was able to destroy tumors and prolong life in most animals treated.

Q: How are Toca 511 & Toca FC administered?
A: Toca 511 is given by injection. Toca FC is taken orally.

Q: Is hospitalization required?
A: Yes. Toca 511 is administered in the hospital. All subsequent tests will be performed on an out-patient basis and Toca FC can be taken at home.

Q: What side effects can be expected?
A: Since the combination of Toca 511 & Toca FC is an investigational therapy, a complete safety profile has not been established. However, Toca 511 & Toca FC has not shown significant toxicity in animal safety studies and has been well tolerated by the human subjects dosed in the clinical study to date. Dose escalation in these studies is ongoing.

Q: What results are expected from the Toca 511 & Toca FC trial?
A: These studies are designed to assess the safety and tolerability of Toca 511 & Toca FC. Additionally, response to treatment will be assessed by measuring tumor size by brain scan (MRI) and progression free survival at 6 months (PFS-6).

Q: If I participate in this study, can I then participate in a vaccine trial?
A: Generally yes, but you should discuss your individual case with your doctor.

Q: How many sites will participate and where are the sites located?
A: Trial sites are located across the US. For an updated site list for the study you are interested in, please visit: and search for Toca 511.

Q: How can someone with a recurrent HGG participate in the clinical trial?
If you are a patient and would like more information regarding your eligibility for this study, please contact the study site location nearest you or contact Tocagen through the Patient Inquiry Form. For more information about this study and a complete listing of inclusion/exclusion criteria, please visit and search for Toca 511.

Q: How can a physician refer a patient with a recurrent HGG?
If you are a physician who would like more information regarding the eligibility of one of your patients, please contact us through the Physician Inquiry Form.