Theranostics 101: Combining Therapeutics and Diagnostics to Treat Prostate Cancer

Theranostics, or the method of using one radioactive drug to diagnose a malignancy and a second radioactive drug to treat that cancer, is gaining in popularity in the treatment of prostate cancer. But while this is a promising option, according to Dr. Phillip J. Koo, further study is needed in the US before it can be approved on a widespread basis.

Koo, the chief of diagnostic imaging at Banner MD Anderson Cancer Center in Phoenix, recently spoke with CURE® about the field of theranostics and how it is poised to make an impact on the treatment of prostate cancer.

More widely available internationally, the use of theranostics in the U.S. is currently limited mostly to clinical trials, some of which are investigating the use of different radioactive isotopes and their potential side effects.

Transcription:

CURE®: What is theranostics, particularly when used in prostate cancer treatment?

Koo: Theranostics is a play on words, it combines the term “therapy,” or therapeutics, with “diagnostics.” And basically, what it's trying to represent is this idea of being able to combine both technologies to make sure we can identify patients who might benefit from a treatment, and then using that information directly to treat a patient with that specific therapy. And this is very relevant because in prostate cancer, the protein prostate specific membrane antigen, PSMA, is very specific for those prostate cancer cells.

It's been around for a while. And we've seen patients being treated on this, particularly international patients. In the United States, it has been much more limited. In the United States, the main access has been through a clinical trial, and mainly the VISION trial, which was sponsored by Advanced Accelerator Applications, which is owned by Novartis. And that was sort of the first opportunity to really get patients in the U.S. enrolled into this trial, as opposed to, you know, recommending patients go to these other countries to get this therapy if they had the resources.

Is theranostics one specific therapy, or a class of multiple therapies?

Currently, it's all being studied with a lutetium-177-PSMA molecule that is called 617. Whether it's lutetium-177, or something like actinium, that really talks about the radioactive material that is being delivered to the cancer cells. So, for the time being, lutetium-177 is what everyone is really focusing on. It's a radioactive material that emits a radiation particle that can kill the prostate cancer cells. So the trial from Australia and the VISION trial are focused on lutetium-177-PSMA. The great thing about that radioisotope is it can kill the prostate cancer cells, you can image patients with that and it has been shown to be very safe.

There are other trials currently in process that are looking at other radio isotopes such as thorium or actinium. These isotopes have maybe higher energy power, but there might be side effects that we need to learn about as well. So, it really again has to be studied very closely before we give it approval.

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