HIV Dormant Strains And Cancer: How Genetic Modification Created A Powerful Potential Cancer Treatment

In our last two blog entries, we’ve discussed pediatric cancer and how Dr. Tom Folks, an early AIDS scientist, was able to grow the HIV virus in laboratory conditions, creating strains that could be used to further research.

Now let’s talk about how the two topics intersect—a modified strain of the HIV virus has show itself to be a potential treatment for some forms of cancer, including pediatric leukemia.

Dr. Folks’ work with the virus had shown that different cell lines could be developed to exhibit different characteristics. One line, for example, was non-infectious and provided researchers with a safe strain for testing. Another line demonstrated how the virus could be dormant within the cell for years, but awakened with the right trigger.

Since then, researchers have created ways to further modify the virus, not just to trigger its activation, but to control the way it affects other cells.


Using The Virus To Enhance The Body’s Defense

HIV attacks T-cells, the same cells that are supposed to defend the body against it. It slips its way in the T-cell, then forces it to make millions of copies of the HIV virus before killing it, eventually overpowering T-cells as the body’s defense mechanism.

But what if the virus is modified so that it doesn’t replicate itself, but instructs the T-cell to attack something else?

That’s what researchers at the University of Pennsylvania discovered when working with highly-modified versions of the HIV virus. The researchers were addressing the cases of several leukemia patients (both adults and children) who had not responded to chemotherapy and who had very short life expectancies.

The researchers found a way to modify the patients’ T-cells by removing them from the body, culturing them, and adding a modified virus strain that specifically targets antigens found on the cancerous cells. The modified cells were then returned to the patient.


Two Pounds of Tumor. Gone.

The results were stunning. In one patient, the modified T-cells destroyed nearly two pounds of tumor. The modification with the virus had dramatically enhanced the ability of the T-cells to target and kill the cancer—turning the T-cells, as one source described, into “serial killers.”

The initial trial was small (ten adults and two children), but the majority of the patients had a positive response. Nine of the patients (many with initial life expectancies of less than a month) are still alive after three years. Some have experienced complete remission. Others in the test had the cancer diminish until their modified T-cells died off, then saw the cancer return. In one case, the patient’s cancer stopped carrying the target antigen, suggesting that multiple targets may be needed for the treatment to be effective.

The sample is too small to draw any conclusions, but more research has been funded and is continuing. And it raises an intriguing possibility: That we may be able to harness the unique trait of a virus that makes it a potent killer, and turn it into a strategy for a cure.

Genetic modification for cancer treatment takes many promising forms. We’ve told you in the past about one of our portfolio companies, Pure MHC, which has found ways to create antibodies that mimic T-cells to target specific cancers. Much more is being done. And we may eventually have multiple avenues of treatment to choose from when battling mankind’s most persistent and difficult disease.


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