In a small clinical trial hailed as a landmark in genetics research, doctors at a leading cancer hospital have reported that gene therapy shrank tumors in lung-cancer patients.
Seven male patients in the final throes of the disease at the M.D. Anderson Cancer Center in Houston received injections of genes that protect the body against cancer.
The experiment marked the first time that scientists successfully have replaced a tumor-suppressor gene in the body. If borne out by further studies, the research could develop a powerful weapon against solid tumors.
Six of the seven Houston patients responded to the treatment after conventional therapies had failed. Significant tumor shrinkage was observed in three men, and the targeted cancer even vanished in one - something rarely seen in relapsed cancer patients with solid tumors. The treated tumors stopped growing in three others, but no effect was noted in the seventh patient.
All the patient-volunteers eventually died, but that had been expected because the disease had spread beyond the tumors that were treated.
The federally approved experiment was designed to restore healthy copies of a tumor-suppressing gene called p53 to cells that had lost them to determine if there was any anti-tumor effect. Flaws in the p53 gene - dubbed the “master watchman” of the human genetic code - are implicated in 60 percent of the million new cancer cases diagnosed each year, and they are particularly common in lung cancer.
The gene performed ably in Houston, showing it could destroy localized deposits of one of the most deadly cancers when nothing else could - not surgery, chemotherapy or radiation.
According to editors of the journal Nature Medicine, which published the study this week, “This paper represents a landmark in the field of gene therapy. … The implications of this work are huge.”
But Dr. Jack A. Roth, the chief researcher, concerned about raising hopes prematurely, said the experiment “proves a principle, but we’re a long way from a cure.”