Abiraterone is a derivative of steroidal progesterone and is an innovative drug that offers clinical benefit to patients with hormone refractory prostate cancer. Abiraterone is administered as an acetate salt prodrug because it has a higher bioavailability and less susceptible to hydrolysis than abiraterone itself. FDA approved on April 28, 2011.
The T-value in the score for hazard refers to chronic toxicity. Underlying data for P, B and T comes from assessment report för Zytiga (abirateron), see below. The risk comes from Fass.se. Below is Hazard and Risk according to data from the assessment report for Zytiga (abiraterone) 12 October 2017, EMA/816845/2017 Hazard Persistence: "DT50, freshwater = 2.3 days, DT50, sediment = ND, DT50, whole system = 4.9 and 3.3 days % shifting to sediment = sediment-bound residue 28.2% and 22.1%." Bioaccumulation: log Kow = 5,12. BCF = "903 (for low conc, 0.13 μg/L), 931 (for high conc, 1.3 μg/L)." Conclusion: B. Chronic toxicity: There is NOEC for 3 trophic levels, lowest NOEC for fish (fathead minnow partial life cycle) 0.013 microg/L. Conclusion: T. PBT-statement: "The compound is considered as T." Risk The risk, PEC/PNEC, calculated from data in the assessment report from a European perspective: PECsurfacewater = 0.004 microg/L PNEC = Lowest NOEC 0.013 microg/L/10 (Assessment Factor (AF) for 3 chronic studies) = 0.0013 microg/L PEC/PNEC = 3.077 Below is Hazard and Risk from Fass environmental information for Zytiga (abirateron) (downloaded 2018-06-29) Hazard Persistence: "Taunton River Aerobic DT50 (Days) Total system = 4.9, Weweantic River Aerobic DT50 (Days) Total system = 3.3. Abiraterone acetate is degraded in the environment." Bioaccumulation: Log Dow > 6.20 (pH = 6.10), "BCFlow dose = 625, BCFhigh dose = 576. Abiraterone acetate has high potential for bioaccumulation." Kronisk toxicitet: There is NOEC for 3 trophic levels, lowest NOEC for fish (fathead minnow Pimephales promelas 119 days) = 0.013 microg/L. Conclusion for PBT-assessment "According to the established EU-criteria Abiraterone acetate should not be regarded as a PBT substance." Risk PEC/PNEC is based on sales data in Sweden in year 2016. PEC/PNEC = 11,7 which gives the risk high.
European Medicines Agency. European public assessment reports (EPAR).