By tweaking a virus known to
attack cancer, San Diego scientists have developed a clever two-in-one
technique for detecting tumors and making them more vulnerable at the
same time. The method was tested in mice, and it could be headed for
human clinical trials in as little as a year.
Researchers at the San Diego biotech company Genelux
genetically engineered the cancer-killing virus to produce melanin,
responsible for skin color and tanning. Tumors infected with the virus
become darker than the surrounding tissue. They become visible through
optical imaging, as well as MRI, or magnetic resonance imaging.
the melanin-darkened tumors preferentially absorb near-infrared light
and covert it to heat. A two-minute exposure killed nearly all of the
tumors by heating them, according to a study published Monday in the Proceedings of the National Academy of Sciences.
clinical trials of this therapy could begin after regulatory approvals
are granted, said Aladar A. Szalay, Genelux president and CEO, and the
study's senior author. The first author is Jochen Stritzker, of Genelux
and the University of Würzburg, in Germany.
virus is from a well-studied variety called vaccinia, so its safety
profile is known, Szalay said. A vaccinia virus was used in the first smallpox vaccine
more than two centuries ago. And Genelux is using the virus in an
ongoing clinical trial that has shown preliminary evidence of safety and
 Hard-to-reach tumors in places such as the brain or pancreas are among the logical choices for the therapy, Szalay said.
Eventually, the melanin technology could become a tool in the new field of "theranostics," combining therapy with diagnosis, the study said.
have been made to use melanin for cancer diagnosis and treatment. But
those failed because the tumor didn't make enough melanin to be
effective, Szalay said. Genelux used a virus known for making huge
amounts of viral protein in the cells it hijacks, causing plentiful
or oncolytic, viruses selectively attack solid tumors because the
tumors tend to be shielded from the body's immune system, which kills
the viruses elsewhere. Biotech companies such as Genelux are working to
enhance such viruses so they can be safely and effectively used in
 Besides vaccina, other oncolytic viruses
used in clinical trials are adenovirus, reovirus, measles, herpes
simplex and Newcastle disease viruses. Conclusive proof of efficacy
remains to be demonstrated.
the existing trial, privately held Genelux is testing a viral cancer
therapy called GL-ONC-1. The trial uses a cancer-killing virus,
genetically engineered to produce a fluorescent protein that shows where
the cancer exists.
November, Genelux said a Phase 1/2 trial showed that the
"virotherapeutic" was well tolerated when applied into the peritoneal
cavity. Analysis of the peritoneal fluid showed malignant cells were
infected and killed by the therapy.
Genelux was founded in 2001 to develop diagnostics and treatments for cancer and inflammatory diseases.
tumors are the most difficult to treat with conventional therapies,
once they have metastasized. Another biotech working with oncolytic
vaccinia viruses in solid tumors, San Francisco-based Jennerex, reported
last week it had achieved positive results in a clinical trial of its therapy for advanced liver cancer.
Results of the study were published in the journal Nature Medicine.
 Jennerex is testing JX-594,
a strain of vaccinia genetically modified to kill cancer cells,
stimulate an immune response against the cancer, and to reduce blood
supply to the tumors by destroying blood vessels.