748P - Switch from abiraterone + prednisone to abiraterone + dexamethasone after PSA progression under abiraterone + prednisone in asymptomatic metastatic...

Date 09 October 2016
Event ESMO 2016 Congress
Session Poster display
Topics Anticancer agents
Prostate Cancer
Therapy
Biological Therapy
Presenter Charlotte Fenioux
Citation Annals of Oncology (2016) 27 (6): 243-265. 10.1093/annonc/mdw372
Authors C. Fenioux1, C. Louvet1, D. Prapotnich2, S. Ropert3, E. Barret2, R. Sanchez-Salas2, A. Mombet2, N. Cathala2, B. Poullennec1, M. Joulia1, M. Ung1, X. Cathelineau2, M. Bennamoun1
  • 1Medical Oncology, Institute Mutualiste Montsouris, 75014 - Paris/FR
  • 2Urology, Institute Mutualiste Montsouris, 75014 - Paris/FR
  • 3Medical Oncology, Hopital Privé, 92160 - Antony/FR

Abstract

Background

Abiraterone acetate (AA) is active in mCRPC. AA is usually administrated with prednisone (P) to prevent mineralocorticoid excess until radiological or symptomatic progression regardless of PSA. A switch from P to dexamethasone (D) was reported to induce tumor responses in patients progressing on AA + P. This prospective study was designed to evaluate outcome of patients (pts) with asymptomatic PSA progression on AA + P after the switch, and to determine predictive factors of switch efficiency.

Methods

Among 120 pts treated with AA between Jan 2013 and Apr 2016 in our institution, 48 consecutive asymptomatic mCRPC pts, progressing only biologically on AA + P 10mg daily, were switched to AA + D 0.5mg daily at the time of PSA increase. AA + D was administered until radiological and/or symptomatic progression.

Results

Median age at switch was 82 ± 7yrs (57–92). Median time of hormonosensitivity was 82 months (mo). 7 pts previously received docetaxel. Median time to PSA progression on AA + P was 8.6 mo. Median (med) follow-up time from switch was 14 mo. Actuarial median PFS's on AA + D and on AA+ corticosteroids (P then D) were 14.5 and 23.1 mo, respectively. 45.8% of pts had a PSA decrease after the switch. Univariate prognostic factors of switch efficiency were long hormonosensitivity duration (> 5 yrs; med PFS 16.6 vs 3.9 mo, p = 0.0012, HR : 4.46 (1.8 – 11.03)), low PSA level at switch (< 50 ng/ml; med PFS 15.2 mo vs 3.8 mo, p= 0.0041, HR 3.23 (1.45 – 7.20)), and short time to PSA progression on AA + P (

Conclusions

Switch from P to D is able to reverse biological resistance to AA + P in almost half of mCRPC pts. Lasting PFS have been observed in pts with previous long hormonosensitivity, and/or low PSA level and/or short time to PSA progression on AA + P. This switch deserves further evaluation in randomized studies.

Clinical trial identification

Legal entity responsible for the study

Institut Mutualiste Montsouris

Funding

Institut Mutualiste Montsouris

Disclosure

C. Louvet: Roche, Sanofi, Celgene.

S. Ropert: Astellas, Bayer.

E. Barret: Astellas.

M. Bennamoun: Janssen, Sanofi, Novartis.

All other authors have declared no conflicts of interest.