Metastatic castration-resistant prostate cancer (mCRPC) patients who have never received chemotherapy benefit more from treatment than post-chemotherapy patients, according to the first reported outcome data from the The Prostate Cancer Registry, Europe’s first and largest prospective study of men with mCRPC.

The results, presented by Janssen-Cilag International at the European Society for Medical Oncology 2016 Congress, which took place Oct. 7-11 in Copenhagen, also reveal that after first-line treatment with Taxotere (docetaxel), patients treated with androgen receptor-targeted agents have higher reductions in PSA levels than those treated with taxanes like Jevtana (cabazitaxel) or Taxotere.

The Prostate Cancer Registry was launched in 2013 as a long-term commitment by Janssen to address optimal treatment of mCRPC in routine practice. It was designed in collaboration with mCRPC specialists and assesses patients being managed in a number of oncology and urology settings, with the aim of reflecting routine clinical practice.

The Registry is collecting data on a pan-European scale on patient demographics and status, treatment sequencing and effectiveness, ongoing disease management, quality of life, medical resource utilization, and outcomes. The analysis is expected to be completed in 2019.

“The Prostate Cancer Registry provides unique insights into the treatment of mCRPC patients from a large, real-world population. With enrollment now complete at over 3,000 patients across 16 countries, there is no other registry in advanced prostate cancer of this size that has produced such a large volume of data,” Simon Chowdhury, PhD, from Guy’s Hospital in London, said in a press release.

These first-ever reported preliminary data suggests that:

• Patients who had not received chemotherapy yet (chemotherapy-naïve patients) had a longer median time to next therapy than patients who already had received chemotherapy (post-chemotherapy patients) when given treatment with androgen receptor-targeted agents (601 days versus 428 days for Zytiga, and 503 days versus 366 days for Xtandi).
• Post-chemotherapy patients had a lower prostate-specific antigen (PSA) response than chemotherapy-naïve patients when given androgen receptor-targeted agents or taxanes.
• After first-line docetaxel treatment, patients had a higher PSA response when given treatment with androgen receptor-targeted agents, like Zytiga (31%) or Xtandi (39%), than with taxanes, like Taxotere (25%) or Jevtana (29%).

“The Prostate Cancer Registry is helping us to address a critical gap in our understanding of the real-world management of patients with mCRPC. This involves studying patients who have high rates of comorbidities and use multiple medications, who are usually excluded from clinical trials,” Chowdhury continued. “Every patient is different and it is extremely important for clinicians to be able to understand how men with mCRPC respond to medications to ensure that we choose the very best treatment for each individual. I look forward to seeing further data as the registry continues.”

Zytiga (abiraterone acetate) is the only approved therapy-inhibiting production of androgen, a male sex hormone that induces prostate cancer growth. It does so by blocking the CYP17 enzyme complex present at three sources: the testes, adrenals, and the tumor.