Tocagen's late-stage study of Toca 511, Toca FC immunotherapy in high-grade glioma fails main goal

Tocagen announced Thursday that a Phase III study evaluating Toca 511 and Toca FC in patients with recurrent high-grade glioma undergoing resection failed to meet its primary endpoint of overall survival (OS) compared to standard-of-care treatment. Shares in the company plunged as much as 81% on the news.

The Toca 5 trial randomised 403 patients undergoing resection for recurrent high-grade glioma to receive Toca 511 and Toca FC or standard-of-care treatment. Tocagen's product is an immunotherapy comprising the retroviral replicating vector Toca 511, which delivers a gene for the enzyme cytosine deaminase, and the investigational small molecule Toca FC, which is a prodrug of 5-fluorouracil.

Results showed that median OS in patients receiving Toca 511 and Toca FC was 11.1 months, compared to 12.2 months in those given standard-of-care treatment. Tocagen added that all of the trial's secondary endpoints also failed to show a meaningful difference between the treatment arms. The company indicated that presentation of the results is planned at an upcoming medical meeting.

Earlier this year, Tocagen said that the study would continue as planned following an interim analysis conducted by an independent Data Monitoring Committee. The first planned interim analysis in 2018 had also reached the same conclusion (for related analysis, see ViewPoints: Tocagen investors decide not to wait this one out).

CEO Marty Duvall remarked "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," adding "in addition, we will be conducting an operational review."

To read more Top Story articles, click here.