Characterization of structural, biochemical, pharmacokinetic, and pharmacodynamic properties of the LSD1 inhibitor bomedemstat in preclinical models.

INTRODUCTION: Lysine-specific demethylase 1 (LSD1) is emerging as a critical mediator of tumor progression in metastatic castration-resistant prostate cancer (mCRPC). Neuroendocrine prostate cancer (NEPC) is increasingly recognized as an adaptive mechanism of resistance in mCRPC patients failing androgen receptor axis-targeted therapies. Safe and effective LSD1 inhibitors are necessary to determine antitumor response in prostate cancer models. For this reason, we characterize the LSD1 inhibitor bomedemstat to assess its clinical potential in NEPC as well as other mCRPC pathological subtypes. METHODS: Bomedemstat was characterized via crystallization, flavine adenine dinucleotide spectrophotometry, and enzyme kinetics. On-target effects were assessed in relevant prostate cancer cell models by measuring proliferation and H3K4 methylation using western blot analysis. In vivo, pharmacokinetic (PK) and pharmacodynamic (PD) profiles of bomedemstat are also described. RESULTS: Structural, biochemical, and PK/PD properties of bomedemstat, an irreversible, orally-bioavailable inhibitor of LSD1 are reported. Our data demonstrate bomedemstat has >2500-fold greater specificity for LSD1 over monoamine oxidase (MAO)-A and -B. Bomedemstat also demonstrates activity against several models of advanced CRPC, including NEPC patient-derived xenografts. Significant intra-tumoral accumulation of orally-administered bomedemstat is measured with micromolar levels achieved in vivo (1.2 ± 0.45 µM at the 7.5 mg/kg dose and 3.76 ± 0.43 µM at the 15 mg/kg dose). Daily oral dosing of bomedemstat at 40 mg/kg/day is well-tolerated, with on-target thrombocytopenia observed that is rapidly reversible following treatment cessation. CONCLUSIONS: Bomedemstat provides enhanced specificity against LSD1, as revealed by structural and biochemical data. PK/PD data display an overall safety profile with manageable side effects resulting from LSD1 inhibition using bomedemstat in preclinical models. Altogether, our results support clinical testing of bomedemstat in the setting of mCRPC.

A phase 1 dose-escalation study: safety, tolerability, and pharmacokinetics of FBS0701, a novel oral iron chelator for the treatment of transfusional iron overload.

BACKGROUND: There is still a clinical need for a well-tolerated and safe iron chelator for the treatment of transfusional iron overload. We describe the pharmacokinetic properties and safety data after 7 days of dosing of FBS0701, a novel oral, once-daily iron chelator. DESIGN AND METHODS: This phase 1b dose-escalation study to assess the safety, tolerability, pharmacokinetics and pharmacodynamics of FBS0701, a novel oral iron chelator for the treatment of transfusional iron overload, was conducted in 16 adult patients with iron overloaded consequent to transfusions. FBS0701 was given daily for 7 days at doses up to 32 mg/kg and was well tolerated at all dose levels. RESULTS: Pharmacokinetics showed dose-proportionality. The maxium plasma concentration (C(max)) was reached within 60-90 minutes of dosing and the drug was rapidly distributed at the predicted therapeutic doses. The plasma elimination half-life (t(1/2)) was approximately 19 hours. There were no serious adverse events associated with the drug. Conclusions On the basis of these safety and pharmacokinetic data, FBS0701 warrants further clinical evaluation in patients with transfusional iron overload. (Clinicaltrials.gov identifier: NCT01186419).