The E3805: CHAARTED trial noted that the addition of D to ADT was associated with a hazard ratio (HR) of 0.56 (95% confidence interval [CI], 0.44 to 0.70; P
A cohort of mCRPC patients (pts) treated with pCRx AA or E for mCRPC between 2014 and 2017 was identified from three hospitals’ IRB approved databases. Patients were grouped by use of D for mHSPC. This time frame was chosen as ADT+D became a valid therapeutic option for mHSPC in 2014 and thus time to pCRx and follow-up were short. The endpoints included OS (time to death from all causes) from ADT start, time to AA/E start from ADT start, and OS from AA/E start. Survival outcomes were analyzed by Kaplan-Meier method.
Of the 102 identified, 50 (49%) had previously received ADT alone, while 52 (51%) had ADT+D. No statistically significant difference in OS from ADT start or from AA/E start was observed between the 2 cohorts (Table 1). Notably, survival in both groups from ADT start was shorter than commonly reported. Yet, deaths in the ADT+D group were 12 vs. 21 in the ADT alone, after a median follow-up of 24.4 and 29.8 months, respectively.
In a cohort of ADT/ADT+D treated mCRPC pts with short times to pCRx AA/E and follow-up, the efficacy of AA/E is similar regardless of previous use of D. It is possible that the pts selected for ADT+D had poorer prognostic factors and yet still did at least as well with AA/E and deaths were lesser. Larger sample sizes, longer follow-up, and better characterization of patient and tumor factors are needed to assess the efficacy of different sequences.Table:
|pCRx AA/E||N (%)||N Deaths (median follow-up mo)||Median OS from ADT start (95% CI mo)||P-value||Time to AA/E start (95% CI mo)||P-value||Median OS from AA/E start (95% CI mo)||P-value|
|ADT||50 (49%)||21 (29.8)||33.5 (22.4 – NR)||0.2047||11.0 (8.5 – 13.7)||0.7265||17.3 (13.7 – NR)||0.6514|
|ADT+D||52 (51%)||12 (24.4)||NR (NR-NR)||12.8 (11.1 – 15.7)||NR (13.1 – NR)|
Clinical trial identification
Legal entity responsible for the study
P. Kantoff: SAB/consulting: Astellas, Bayer, Bellicum, BIND Biosciences Inc, BN Immunotherapeutics, DRGT, Ipsen Pharmaceuticals, Janssen, Metamark, MTG Therapeutics, New England Research Institutes, Omnitura, OncoCellMDX, Progenity, Sanofi, Tarveda Therapeutics. M.E. Taplin: Research funding and advisory board for Janssen and Medivation. N. Alimohamed: Consulting or advisory role for: Bayer, Sanofi, Pfizer, Astellas, Merck Inc., Novartis Pharma, Roche-Peru. D.Y.C. Heng: Consulting or advisory role: Pfizer, Novartis, Bristol-Myers Squibb, Janssen, Astellas Pharma. C.J. Sweeney: Consultant with compensation for: Astellas, Bayer, Genentech, Janssen, Pfizer, Sanofi. Research funding from: Astellas, Janssen, Sotio, Sanofi. All other authors have declared no conflicts of interest.