A Phase III clinical trial performed by Tocagen to assess its cancer immunotherapy, Toca 511 & Toca FC, has failed to meet the primary endpoint of overall survival in patients with recurrent high grade glioma (HGG), a form of brain cancer.
The immunotherapy is a two-part product made of an investigational retroviral replicating vector (RRV) Toca 511 and investigational oral small molecule Toca FC.
Toca 511 specifically infects cancer cells and delivers a gene for the cytosine deaminase (CD) enzyme.
Toca FC is a 5-fluorocytosine (5-FC) prodrug that converts into an anti-cancer drug called 5-fluorouracil (5-FU) upon encounter with CD. 5-FU destroys cancer cells and immune-suppressive myeloid cells.
The multi-centre, randomised, open-label Phase III trial, named Toca 5, compared the cancer immunotherapy to standard of care in more than 400 patients undergoing resection.
According to the study results, Toca 511 & Toca FC did not meet the primary endpoint, demonstrating 11.1 months of median overall survival versus 12.2 months with standard of care.
No meaningful difference was observed in all secondary endpoints between the study groups.
The secondary outcomes included durable response rate, durable clinical benefit rate, and overall survival at 12 months.
Tocagen CEO Marty Duvall said: “While the Toca 5 trial results are disappointing, we will be conducting a thorough analysis of the data including molecular analyses and pre-planned subgroups. In addition, we will be conducting an operational review.”
These results come shortly after Bristol-Myers Squibb’s Opdivo (nivolumab) combination therapy failed to meet the primary endpoint of progression-free survival (PFS) in patients with glioblastoma multiforme (GBM), also a type of brain cancer.