Prostate tumors that have spread to people’s bones can be reduced in size, by a newly found cancer drug, which also helps alleviate bone pain, according to a new study.

A novel cancer therapy callled Cabozantinib, which targets tumors specifically, was found to have clear and impressive results. The scientists say the trial results will be announced on September 30th at the European Society of Medical Oncology congress in Vienna.

Previous research from May of this year indicated that a different drug, abiraterone acetate (Zytiga(R)) also greatly benefits men with prostate cancer, whose cancer has not yet metastasized. The results from the phase II trial on this treatment showed that it can can help eliminate or almost eliminate tumors in those patients.

Cabozantinib, developed by Exelixis, is an oral drug known as a kinase inhibitor. It works by blocking two molecules that aid in the growth and spread of cancer:

  • VEGFR2– what the cancer uses to form new blood vessels so they can take nutrients in the blood system
  • MET– abnormally activated in prostate cancer

A Phase II trial was conducted by Professor Johann de Bono at The Institute of Cancer Research, London, and honorary consultant at The Royal Marsden NHS Foundation Trust, and his team, in order to analyze the beneficial results of this medication in 51 men suffering from metastatic castration-resistant prostate cancer.

All of the subjects were in a dangerous stage of the disease prior to research, where the tumor had spread to their bones. They had previously undergone chemotherapy, which did not prevent it from spreading.

After examining the brain scans of 20 of the individuals after receiving the treatment, a reduction in the size of the tumor was seen in 11 of them.

About 50% of participants in the trial were suffering from pain and discomfort, even though most of them were taking strong painkillers, such as morphine.

Approximately 70% of those evaluable after receiving treatment saw a significant decrease in pain (10/14 patients), while over 50% (7/12 patients) stopped taking painkillers as often.

The subjects noted that their daily life became less impacted by the disease. They were able to get more rest and function more properly in their daily activities. However, they did experience some negative side-effects, the most common being decreased appetite, back pain, and high blood pressure.

Professor de Bono explained:

“Although we have helped develop a number of new drugs for advanced prostate cancer over recent years, men’s tumors ultimately develop resistance to treatment and so finding new options for men with late-stage disease is still crucially important. As prostate cancer progresses, it commonly spreads to men’s bones, which can lead to bone fractures and severe pain. This drug has so far only been tested in a small number of patients and isn’t curing them of their cancers, but it is showing promise at taking away the pain of prostate cancer and helping men live a normal life.”

Professor Alan Ashworth, chief executive of The Institute of Cancer Research (ICR), added:

“This is an exciting time for prostate cancer research, with four new drugs shown to extend life in advanced cancer in the last two years- three of which the ICR has helped develop. This latest treatment is another of the new generation of drugs precisely targeted at tumors, and it’s promising that it is showing clear signs of activity and patient benefit.”

Written by Sarah Glynn