Initial experience of the adjuvant treatments to the local tumor for metastatic prostate cancer: Assessment of novel treatment algorithms, a multicenter, phase II randomized controlled trial (IP2-ATLANTA)

TPS5600 Background: Local cytoreductive and metastasis-directed interventions are hypothesised to confer additional survival benefit beyond standard systemic therapy in patients with de novo synchronous metastatic prostate cancer. There is accumulating prospective evidence for local cytoreductive therapy. In particular, the phase III study STAMPEDE which demonstrated improved overall survival in a low burden subgroup of men following cytoreductive radiotherapy. Cytoreductive prostatectomy and minimally invasive ablative therapies (MIAT) are now subject to similar trial evaluation. IP2-ATLANTA will evaluate progression-free and overall survival outcomes with the addition of sequential multi-modal local and metastasis-directed treatments in patients with newly diagnosed metastatic prostate cancer compared to standard care alone. Methods: Phase II, multicentre, three-arm randomised controlled trial using a positive comparator arm ( n=918 ). An internal pilot ( n=80) feasibility phase is incorporated. All men with new histologically diagnosed, hormone sensitive, metastatic prostate cancer, within three months of commencing ADT and of PS 0-2 are eligible. Patients are randomised (1:1:1) to: Control (Standard of Care) OR Intervention 1 (Minimally invasive ablative therapy to the prostate +/- pelvic lymph node dissection [PLND]) OR Intervention 2 (prostate radiotherapy +/- lymph nodes OR Radical prostatectomy +/- PLND). Metastatic burden pre-specified by CHAARTED definition. Men with low-burden disease in intervention arms are eligible for metastasis-directed therapy (stereotactic ablative radiotherapy [SABR] or surgery). Standard systemic therapy given in all arms (incl. docetaxel). Follow-up: min. 2-years; max. 4 years. Primary outcome: progression-free survival (PFS). Secondary outcomes: Overall survival; urinary, sexual & rectal side-effects; patient reported outcome measures. HRA ethical approval (Ref: 19/WA0005). To date, 28/80 (35%) patients have been recruited and randomised across 9 open sites in the internal pilot. Median recruitment rate is 85.7% (IQR 55–86). Internal pilot recruitment expected to be complete by April 2020. IP2-ATLANTA addresses an important research gap in the role of local and metastasis-directed therapy in men with newly diagnosed metastatic prostate cancer. Clinical trial information: NCT03763253 .