There are new treatment options for castration resistant prostate cancer (CRPC) but finding the optimal strategy and selecting the right patient is still fraught with challenges and difficulties, according to uro-oncology experts during a thematic session at the 29th Annual EAU Congress in Stockholm, Sweden.
“With many prostate cancer patients hoping for a better life without symptoms of the disease, the aim is to identify which new drugs, or a combination of these drugs, can offer prolong survival or effectively palliate bone disease,” said Prof. Maria De Santis who chaired Thematic Session 10.
The session focussed on castration-resistant prostate cancer (CRPC) which is often considered one of the toughest challenges in uro-oncology since despite repeated treatments the disease accelerates or progresses with severe impact on quality of life (QoL) .
Prof. Kurt Miller (DE) spoke on the availability of modern second-line hormonal manipulation and presented a concise overview of new hormonal agents as well as new concepts to prolong survival. He noted the entry of agents such as enzalutamide (formerly called MDV3100), an androgen receptor inhibitor that acts on different steps in the androgen receptor signaling pathway.
Recent studies showed that enzalutamide significantly prolonged the survival of men with metastatic castration-resistant prostate cancer after chemotherapy. The question, according to Miller, would be to find out the optimal sequence.
Speaking on the topic “New ways to target bone metastases,” Prof. Susanne Osanto (NL)said the main challenges are to delay the onset of skeletal-related events (SREs), improve QoL, and prolong overall survival.
She mentioned the studies comparing denosumab and zoledronic acid, and said the former is clearly superior to zoledronic acid. “SREs are reduced by 18%...denosumab is clearly superior compared with zoledronic acid,” she said adding that in studies comparing denosumab versus placebo, denosumab delayed SREs and increased overall survival (OS).
Regarding Radium 223, a short range alpha-emitter which reduced bone marrow exposure, Osanto said there is not only a “clear OS benefit” to patients but there is also delay of SREs, pain palliation, and good QoL.
“It’s clear that there is OS in those patients with Radium 223…it was performing very nicely and is well-tolerated and with few adverse effects. It also shows a favorable safety profile,” added Osanto.
Prof. Peter Mulders (NL) gave an overview on immunotherapy strategies in CRPC and mentioned vaccines such as Prostvac and Provenge, with the latter showing a positive phase 3 study with regards to survival. He noted that compared to hormonal therapy, CRPC patients who were given immunotherapy do not show a quick response.
“If you give immunotherapy, you need to wait for the response. There is delayed effect with vaccines, although there is a kind of stabilisation of the disease,” said Mulders.
“Immunotherapy is the future,” added Mulders as he highlighted the positive results shown by Prostvac, with recent studies showing strong preliminary evidence of activity and the potential for safe and rational combinations.