Young Czech scientist develops revolutionary prostate cancer treatment

Prostate cancer is the second most common cancer among men worldwide and the most common in the Czech Republic. The incidence of the disease in Czechia has risen by as much as 70 percent since the early 1990s. Martina Benešová, a young Czech researcher, is part of a team at the German Cancer Research Center in Heidelberg which developed a revolutionary new treatment for patients with a very advanced stage of prostate cancer for whom other treatments had proved ineffective. I spoke to her and started by asking what is new about PSMA-617 compared to previous prostate cancer treatment methods.

Martina Benešová | Photo: Česká hlava

“Endoradiotherapy with PSMA-617 is very special in multiple ways. One of these is that it is so-called theranostic, meaning you can use it for both diagnosis and treatment. It is also new in the way that it works for patients who already received all available therapies for prostate cancer, and despite the fact that they were resistant to all these therapies which are approved and accepted and in use, the application of endoradiotherapy with PSMA-617 works in these patients who have practically no other treatment options.”

You worked in a research team at the German Cancer Research Center in Heidelberg - what was your personal contribution to the development of PSMA-617?

“The development of PSMA-617 was in fact the topic of my doctoral thesis, so I was responsible for the development of theranostic pharmaceuticals which could be used for both diagnosis and treatment. I was responsible for the design, then for the synthesis of those pharmaceuticals and also for their pre-clinical evaluation, and then the clinical translation which was then carried out by the university clinic in Heidelberg.”

PSMA-617 only targets healthy cells, so does that mean it doesn’t cause unpleasant side effects in the way that, say, chemotherapy does? Were there any side effects found in clinical trials?

Photo illustrative: mwooten,  Pixabay,  Pixabay License

“Our pharmaceutical is targeted, which means it selectively binds to prostate cancer cells, and there is some physiological accumulation, especially in the kidneys and salivary glands. But PSMA-617 is so successful because the wash-out from the kidneys is very quick, meaning it does not harm the kidneys. And regarding the salivary glands, at the beginning of the treatment some side effects such as xerostomia were seen, meaning the patients had dry mouth, because the pharmaceutical accumulated in the salivary glands. However, this was solved during the clinical trials by applying the proper dosage. Xerostomia is not such an issue anymore and it’s also reversible. So PSMA-617 definitely has less side effects than all the other systemic therapies.”

Could it theoretically be extended to treat other types of cancer?

“There are already a few new experiments and trials which could potentially apply PSMA-617 to, for example, cancer of the salivary glands, which also expresses the target which is of interest to the pharmaceutical. There were also some kidney cancer patients who were diagnosed, and maybe hopefully also in the future treated with PSMA-617, so there are definitely some other types of cancer which might potentially be interesting also for PSMA-617, however it needs proof of concept in patients and then in clinical trials.”

The treatment has had striking results – it has saved or extended the lives of several thousand patients in which previous treatments had not been effective. But it was only used on men with a very advanced stage of prostate cancer. Would it be effective if it were used earlier, or is it unnecessary because we already have sufficient treatment methods for early-stage cancer?

“There are for sure some patients who have an aggressive type of prostate cancer, and due to this there were two new phase-3 clinical trials recently, which are evaluating the application of endoradiotherapy with PSMA-617 before the application of chemotherapy and in some cases even before hormonal treatment, which is the first choice for patients with disseminated disease. So there is indeed this intention, and if those new big clinical trials go well, then there’s a possibility that in some patients endoradiotherapy might be given sooner than all the other available existing treatments.”

Is the drug still experimental? When will it be available to patients?

“PSMA-617 received FDA approval in March this year, so in the United States it’s not an experimental treatment anymore but could be applied. We are expecting, based on press releases, an approval by the European Medicines Agency (EMA) at the end of this year or at the beginning of next year, and then after these new clinical trials finish and if the results are positive, there might be another FDA and EMA approval for the earlier application of the treatment in prostate cancer patients.”