Radiographic PFS benefit of adding abiraterone to ADT and docetaxel in mCSPC

Adding abiraterone to androgen deprivation therapy (ADT) and docetaxel significantly improved radiographic progression-free survival (rPFS) in men with de novo metastatic castration-sensitive prostate cancer (mCSPC). This benefit is seen both in high-volume and low-volume metastatic disease. There was no meaningful additional short-term toxicity.

In the last decade, the standard of care (SOC) for men with mCSPC has changed dramatically. Initially, ADT alone was SOC for these patients. In 2015, docetaxel was shown to improve survival. Two years later, the LATITUDE and STAMPEDE trials showed a survival advantage of the addition of abiraterone. In 2019, two additional trials confirmed the advantage of adding 2 other anti-androgen pathway signalling inhibitors, apalutamide or enzalutamide. Radiotherapy to the prostate for oligometastatic (low-volume) disease has also been shown to improve overall survival. The accrual of the phase 3 PEACE-1 trial (NCT01957436) began in 2013. Due to the evolving SOC of these patients, various amendments were implemented during the course of the trial [1].

PEACE-1 included 1,173 men; 57% had a high metastatic burden and 60% received docetaxel. The addition of abiraterone to ADT with or without docetaxel and radiotherapy (i.e. SOC) was associated with a significant improvement in rPFS compared with SOC. Specifically, rPFS improved from a median of 2.0 years to 4.5 years (HR for progression 0.50; P<0.0001; see Figure). “So, we are adding 2.5 years – a big difference,” Prof. Karim Fizazi (University of Paris-Saclay, Villejuif, France) said. The benefit of abiraterone was consistent across subgroups analysed.

Figure: rPFS in the ADT plus docetaxel population [1]



Abi, abiraterone; ADT, androgen deprivation therapy; CI, confidence interval, SOC, standard of care, rPFS, radiographic progression-free survival.
Figure kindly provided by Prof. Fizazi.

Overall survival data are not yet mature, so the question remains whether this triplet therapy should be incorporated as a new SOC for patients with de novo mCSPC.

1. Fizazi K. Abiraterone acetate plus prednisone added to androgen deprivation therapy and docetaxel in men with de novo metastatic castration-sensitive prostate cancer (mCSPC): detailed analysis of radiographic progression-free survival in the PEACE-1 phase 3 trial. Game changing session 1, EAU21 Virtual, 8–12 July 2021.

 

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Posted on 31 August 202117 May 2024