WEDNESDAY, Aug. 31 (HealthDay News) -- A new type of cancer treatment that uses a virus to infect and destroy tumor cells without harming normal cells is showing promise in early clinical trials.
The small, Phase 1 trial involved 23 patients with advanced cancers that had spread to multiple organs and who had exhausted other treatment options.
Each received an intravenous infusion of a virus called JX-594 at one of several dose levels. The virus was genetically engineered to contain an immune-stimulating gene to enhance its cancer-fighting properties, explained study co-senior author John Bell, a senior scientist at Ottawa Hospital Research Institution in Ontario, Canada.
Patients underwent biopsies eight to 10 days later. In seven of eight patients (87 percent) who received the highest two doses, researchers found evidence that the virus had not only infected the tumor cells while sparing healthy cells, but that the virus was replicating. Replication means that the virus is reproducing and infecting neighboring cancer cells, rather than just infecting tumor cells it directly came into contact with.
There was also evidence that the foreign immune-stimulating gene was expressed inside the tumor cells.
"This is a landmark observation in that it shows it's possible that a virus can find tumors, specifically grow in tumors but not in regular tissues, replicate and destroy them," Bell said.
The current trial was designed primarily to prove that it was both possible and safe to use a virus to infect tumor cells, and that the virus would then replicate. Side effects were minimal, with the main being brief and mild flu-like symptoms, researchers said.
Though larger trials are needed to determine efficacy, about 75 percent of patients in the two highest dose groups also saw a shrinking or stabilization of their tumor, while those in lower dose groups wer
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