Risky cancer therapy with HI viruses in leukemia

Leukemia sick girl saved by altered immune cells

13.12.2012

American physicians are celebrating a success in cancer therapy these days: Emily, who is suffering from leukemia, was able to beat the blood cancer by an experimental therapy with HI viruses. The high-risk cancer therapy had previously been tested on ten patients, but with mixed success. In the seven-year-old girl, the therapy with the altered immune cells suggested very well, after initially life-threatening side effects had occurred. Whether the new process means a breakthrough in cancer treatment remains to be seen. Because the HI viruses did not successfully fight the cancer cells in all patients. Nevertheless, the pharmaceutical company Novartis already anticipated a great opportunity in the therapeutic procedure in August and has secured the rights to commercialization. It will take a lot of research to be done before it can be put into practice by immunotherapy from the current experimental stage, experts say.

Deactivated HI viruses transmit genetic material to T cells
Earlier this week, at the annual American Society of Hematology conference in Atlanta, Carl June introduced the case of little Emily, who is now being celebrated as a sensation. The University of Pennsylvania immunologist and his team managed to save the lives of seven-year-olds suffering from acute lymphoblastic leukemia (ALL) by experimenting with genetically modified HIV viruses. Previously, no therapy had struck against this aggressive form of blood cancer in the girl.

In the novel method, known under the name CTL019 in the art, the body's own T cells are genetically reprogrammed by deactivated HI viruses in the laboratory, so that they are able to turn off diseased cells. The so-called CART cells (chimeric antigen-receptor T cells) fight the B cells in the body of the patient, which also includes the blood cancer cells. „For the T cells to attack the cancer, we need to add a new gene“, said the attending physician, Stephan Grupp to the news channel „ABC“. „This gene allows T cells to produce a protein that encourages them to fight the cancer. For this new gene to enter the T cells, we use a virus developed on the basis of HIV.“ However, this could not cause illness. „It is impossible to get HIV or another infection“, emphasized the expert in pediatric oncology.

Risky cancer therapy has strong side effects
As promising as the new therapy for leukemia may be, its side effects can be life-threatening. After implanting the altered T cells, Emily showed flu-like symptoms. Her condition worsened dramatically, so the girl had to be treated in intensive care. A drug used in rheumatoid arthritis eventually helped Emily. According to the doctors, Emily is doing well now. Investigations of the bone marrow have shown that it is free of cancer cells today. The T-cells, which fight the blood cancer, are still in the blood of the child, which should prevent a relapse.

Emily is going back to school. Nevertheless, Grupp spoke cautiously about the health of the seven-year-olds. „According to test results, she currently has no leukemia - which also gave the most sensitive tests“, explained the doctor. „We must wait for the development of the next few years before we can say if it is healed or not. It is still too early for that.“

As June reported at the congress, there were other successes besides Emily. The blood cancer cells were completely displaced in two out of three patients with chronic leukemia. In the third patient, this was at least partially succeeded. In another child, CTL019 therapy initially appeared to be effective. However, it suffered a relapse after a short time. The situation was similar in four other patients, whose condition was improved by therapy, but not enough cancer cells could be destroyed. In two cases, the therapy did not start at all.

The pharmaceutical company Novartis has high hopes for the new therapeutic procedure. The company formed a research alliance with Pennsylvania University in August and the „Center for Advanced Cellular Therapies“ in Philadelphia. Novartis holds the rights to the commercialization of CART immunotherapy. However, critics see this as a threat to the independence of research. (Sb)

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New cancer therapy: with viruses against tumors?

Image: Gerd Altmann (image is a tracing)