A combination of two drugs for prostate cancer is safe and shows signs of effectiveness in patients with advanced, aggressive disease, an early-stage trial reports.
The combination will now be assessed further to see whether it could successfully extend life in men with advanced prostate cancer.
An international team led by researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust gave men a combination of abiraterone and cabazitaxel in a two-stage trial.
Abiraterone was discovered at the ICR and is now benefiting hundreds of thousands of men with advanced prostate cancer globally. Cabazitaxel is also a standard treatment – but the two drugs are not currently used together.
No severe side-effects
In phase I of the trial, nine men had their response to the combination treatment measured. All had already received doxetaxel, the standard first-line chemotherapy for advanced, metastatic prostate cancer.
None of the men had severe side-effects from receiving the drugs.
Some 27 men received abiraterone and cabazitaxel in the phase II stage, with 12 having a significant drop in their levels of prostate specific antigen (PSA) – a blood marker of prostate cancer severity.
Of 14 men with measurable cancer at the start of the trial, three showed signs of tumour shrinkage. In total, nine men on the phase II trial had their doses lowered over the course of the trial because of side-effects.
Early-stage cancer trials are typically conducted in people with very advanced disease who have run out of standard treatment options, and are used to provide evidence for sufficient safety and effectiveness to justify larger-scale evaluation.
Recommended for phase III trials
Study leader Professor Johann de Bono, Regius Professor of Cancer Research at the ICR and Consultant at The Royal Marsden, said: “In recent years, several new drugs have become available to men with advanced prostate cancer, leading to a major shift in how doctors approach treatment and significantly extending life. One of the challenges now is to find the best sequences and combinations of these treatments to further extend life for these men, and to give them the best possible quality of life.
“This study establishes the abiraterone-cabazitaxel combination as safe and gives enough evidence of benefit to recommend it progresses to a phase III trial.”
Paper: Massard, C, et al. Phase I/II trial of cabazitaxel plus abiraterone in patients with metastatic castration-resistant prostate cancer (mCRPC) progressing after docetaxel and abiraterone. Ann Oncol (2017) 28 (1): 90-95. DOI: https://doi.org/10.1093/annonc/mdw441