Adding docetaxel to androgen deprivation therapy (ADT) did not produce a clinically meaningful improvement in survival or testosterone recovery among prostate cancer patients with high-risk biochemical recurrence after prostatectomy, according to results of the phase 3 TAX3503 trial published in European Urology Oncology.
Although biochemical recurrence occurs in up to 30% of prostate cancer patients after radical prostatectomy, there is no standard treatment based on comparative trials. The aim of the TAX3503 trial was to evaluate the efficacy and safety of docetaxel plus ADT in this population.
The multicenter TAX3503 trial (ClinicalTrials.gov Identifier: NCT00514917) randomly assigned 413 patients with biochemical recurrence after prostatectomy to receive ADT with or without docetaxel for 18 months. The primary endpoint was progression-free survival (PFS) after testosterone recovery to noncastrate levels, and secondary endpoints included time to testosterone recovery, overall survival (OS), and safety.
At baseline, the median age in both treatment groups was 66 years. The Gleason score was 8 or higher among 28% of all patients, the median prostate-specific antigen (PSA) level was 0.8, and the median PSA doubling time was 3.9 months.
At a median follow-up of 33.6 months, there was no improvement in PFS with docetaxel. The median PFS was 26.2 months in the docetaxel arm and 24.7 months without docetaxel (hazard ratio [HR], 0.80; 95% CI, 0.61-1.04).
Similarly, there was no improvement in OS with docetaxel. The median OS was not yet reached for either arm (HR, 0.51; 95% CI, 0.23-1.10).
The probability of testosterone recovery within 1 year of the end of treatment was similar between the treatment groups, at 0.89 with docetaxel and 0.85 without docetaxel (P =.21).
There were more grade 3 or higher adverse events in the docetaxel arm than in the ADT-alone arm — 48.0% and 10.8%, respectively.
The authors concluded that the trial “did not demonstrate a meaningful benefit of adding docetaxel to ADT in patients with high-risk [biochemical recurrence].”
Disclosure: This research was supported by Sanofi. Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Morris MJ, Mota JM, Lacuna K, et al. Phase 3 randomized controlled trial of androgen deprivation therapy with or without docetaxel in high-risk biochemically recurrent prostate cancer after surgery (TAX3503). Eur Urol Oncol. Published online May 18, 2021. doi:10.1016/j.euo.2021.04.008