There is a new study that shows that an alpha-particle emitting radiopeptide—radioactive material bound to a synthetic peptide, a component of protein—is effective for treating prostate cancer in mice, according to researchers. The conclusions of this study could eventually (still years away if it also works in men) result in a significant breakthrough in advanced prostate cancer treatment. This type of treatment would be a systemic treatment that is able to kill small tumors, a description of prostate cancer.

“Our study shows that this novel form of treatment has the potential to target and destroy cancer cells with minimal damage to surrounding healthy tissue,” said Damian Wild, University Hospital Basel, Basel, Switzerland, lead author of the study. “Eventually, this therapy could give hope to some of the hardest-to-treat prostate cancer patients and also could be applied to other types of cancer.”

Prostate cancer tumor cells readily bind with certain peptides in the body and researchers in this study have been able to develop highly specific radiopeptides (radioactive peptides) that bind with tumor cells and then cause their death. Prostate cancer cells—and many other types of cancer cells—have an overabundance of gastrin releasing peptide receptors, making the cancer a strong candidate for treatment with this type of treatment, radiopeptides.

The study compared two different types of radiopeptides. One group of mice was injected with 213 Bi-DOTA-PESIN, which emits alpha particles that are effective at killing cancer cells. The other group was injected with beta-emitting 177 Lu-DOTA-PESIN, which are also effective in tumor cell killing, but can also cause damage to nearby healthy cells. Alpha particles are able to kill cancer cells without damaging surrounding healthy tissue. A third group of mice received no treatment (the control group).

At the maximum tolerated dose, the alpha-emitting 213 Bi-DOTA PESIN was significantly more effective and did not damage healthy surrounding cells. It tripled the survival rate of the mice that received the therapy. The results indicate that the alpha-emitting radiopeptide could provide a new approach for treating prostate cancer and eventually other types of cancer.

This work still needs to be replicated and then moved into phase I and II trials using men.

Source: Society of Nuclear Medicine

Joel T Nowak MA, MSW