A first-in-human study of the oral selective androgen receptor down-regulating drug (SARD) AZD3514 in patients with castration-resistant prostate cancer (CRPC).

4511 Background: AZD3514 is a first in class, orally bio-available drug that inhibits androgen-dependent and –independent androgen receptor (AR) signaling through two distinct mechanisms; inhibition of ligand-driven nuclear AR translocation and down-regulation of AR levels. Methods: A rolling six design was employed initially using a once a day (QD) schedule (A). PK assessments led to a change to twice daily (BD) dosing (B) to increase exposure. PK profiles were studied over 96 hours after a single dose and over 24 hours at start of/following 21 days continuous dosing. PD analyses included PSA and CTC quantification. Results: 49 CRPC patients (pts) have been treated with escalating doses of AZD3514 (A 35 pts, B 14 pts). Starting doses were 100 mg (A) and 1000 mg (B). The AZD3514 formulation was switched from capsules to tablets at 1000mg (QD). 2000mg BD was considered non-tolerable due to multiple grade 2 toxicities (nausea [N], vomiting [V], fatigue). No adverse events (AEs) met the DLT definition. The m...