Abiraterone added to ADT + docetaxel nearly doubles survival in de novo mCSPC

First results from the phase 3 PEACE-1 trial showed that adding abiraterone to androgen deprivation therapy (ADT) plus docetaxel significantly improved progression-free survival in patients who present with de novo metastatic castration-sensitive prostate cancer (mCSPC), without meaningful added short-term toxicity.

Historically, ADT was the standard of care for men with mCSPC. Since 2015, combining ADT with either docetaxel, novel hormonal therapies (abiraterone, enzalutamide), or radiotherapy to the primary tumour has shown to improve overall survival and, thus, became the new standard of care [1-4]. However, it was unknown whether combining these new treatments on top of ADT further increments outcomes.

The primary goal of the PEACE-1 trial (NCT01957436) is to evaluate the efficacy and safety of the addition of abiraterone, radiotherapy, or abiraterone plus radiotherapy to standard of care. A total of 1,173 men with de novo mCSPC were randomised to standard of care, standard of care plus abiraterone, standard of care plus radiotherapy, or standard of care plus abiraterone plus radiotherapy. No interaction was detected between the effect of abiraterone and that of radiotherapy (P=0.64), allowing to pool the abiraterone arms for comparisons: 589 patients were enrolled in the standard of care (± radiotherapy) arm and 583 patients were enrolled in the standard of care (± radiotherapy) plus abiraterone arm. The trial has 2 co-primary endpoints of radiographic progression-free survival and overall survival. Dr Karim Fizazi (Institut Gustav Roussy, France) presented the first results of PEACE-1 [5].

After a median follow-up of 3.5 years, median radiographic progression-free survival was 4.5 years in the standard of care plus abiraterone arm versus 2.2 years in the standard of care arm (see Figure). Median castration-resistant-free survival was 3.8 years and 1.5 years, respectively. The relative improvement of progression-free survival was comparable in patients treated with or without docetaxel. No meaningful additional toxicity was observed in patients treated with standard of care plus abiraterone.

Figure: Radiographic progression-free survival in the overall population of PEACE-1 [6]

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   1. Sweeney CJ, et al. N Engl J Med. 2015;373:737-746.
   2. Fizazi K, et al. N Engl J Med. 2017;377:352-360.
   3. Davis ID, et al. N Engl J Med. 2019;381:121-131.
   4. Parker CC, et al. Lancet 2018;392:2353-2366.
   5. Fizazi K, et al. A phase 3 trial with a 2x2 factorial design of abiraterone acetate plus prednisone and/or local radiotherapy in men with de novo metastatic castration-sensitive prostate cancer (mCSPC): First results of PEACE-1. Abstract 5000, ASCO 2021 Virtual Meeting, 4–8 June.

 

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Posted on 12 August, 202123 December, 2021