San Diego’s Tocagen, a biotech developing gene therapy treatments for terminal cancers, says it has raised nearly $7.8 million from 75 investors in a Series D round that began Feb. 2, according to a recent regulatory filing. Tocagen, which also raised about $3 million last month by selling preferred shares, says in the filing that it intends to raise a total of $8 million.
Harry Gruber, Tocagen’s founding CEO and a gene therapy pioneer, declined to comment by phone today. The company, which was founded in 2007, raised about $11 million last year.
To get some idea of what Tocagen is doing, I searched some public records for the company’s activities. It turns out Tocagen has proposed a clinical trial that would use a “replication-competent retrovirus” to carry and express a gene known as cytosine deaminase (CD) in the brains of patients with a malignancy known as glioblastoma multiforme, according to the minutes of a June 17 meeting of the National Institutes of Health Recombinant DNA Advisory Committee. Doug Jolly, Tocagen’s senior vice president for research and development, and Manish Aghi, an assistant professor of neurosurgery and principal investigator of the Brain Tumor Research Center at the U.C. San Francisco Medical Center, explained the proposed experiment in a presentation to the committee.
The CD gene functions biologically by converting flucytosine, an FDA-approved and widely used antifungal drug, into fluorouracil, which also is an approved and widely used anticancer drug. In mouse studies, Tocagen showed it could deliver a functioning copy of this gene into brain cancer cells. The brain cancer cells then act as a reservoir for the virus to multiply—and to spread in a highly selective way into other brain cancer cells nearby.
I couldn’t tell what the latest status is of the clinical trial. But it’s not listed among the active trials in the NIH’s clinicaltrials.gov database.
