Drug-Drug Interaction Potential of Darolutamide: In Vitro and Clinical Studies

Background and Objectives

Darolutamide is a novel androgen receptor (AR) antagonist approved for the treatment of nonmetastatic castration-resistant prostate cancer (nmCRPC). Accordingly, the drug–drug interaction (DDI) potential of darolutamide was investigated in both nonclinical and clinical studies.

Methods

In vitro studies were performed to determine the potential for darolutamide to be a substrate, inducer or inhibitor for cytochrome P450 (CYP) isoforms, other metabolizing enzymes and drug transporters. A phase I drug-interaction study in healthy volunteers evaluated the impact of co-administering rifampicin [CYP3A4 and P-glycoprotein (P-gp) inducer] and itraconazole [CYP3A4, P-gp and breast cancer resistance protein (BCRP) inhibitor] on the pharmacokinetics of darolutamide. Two further phase I studies assessed the impact of co-administering oral darolutamide on the pharmacokinetics of midazolam (sensitive CYP3A4 substrate) and dabigatran etexilate (P-gp substrate) and the impact on the pharmacokinetics of co-administered rosuvastatin [a substrate for BCRP, organic anion-transporting polypeptide (OATP)1B1, OATP1B3 and organic anion transporter (OAT)3].

Results

In vitro, darolutamide was predominantly metabolized via oxidative biotransformation catalyzed by CYP3A4 and was identified as a substrate for P-gp and BCRP. The enzymatic activity of nine CYP isoforms was not inhibited or slightly inhibited in vitro with darolutamide, and a rank order and mechanistic static assessment indicated that risk of clinically relevant DDIs via CYP inhibition is very low. In vitro, darolutamide exhibited no relevant induction of CYP1A2 or CYP2B6 activity. Inhibition of BCRP-, P-gp-, OAT3-, MATE1-, MATE2-K-, OATP1B1- and OATP1B3-mediated transport was observed in vitro. Phase I data showed that darolutamide exposure increased 1.75-fold with co-administered itraconazole and decreased by 72% with rifampicin. Co-administration of darolutamide with CYP3A4/P-gp substrates showed no effect or only minor effects. Rosuvastatin exposure increased 5.2-fold with darolutamide because of BCRP and probably also OATPB1/OATPB3 inhibition.

Conclusions

Darolutamide has a low potential for clinically relevant DDIs with drugs that are substrates for CYP or P-gp; increased exposure of BCRP and probably OATP substrates was the main interaction of note.

Electronic supplementary material

The online version of this article (10.1007/s13318-019-00577-5) contains supplementary material, which is available to authorized users.

Evaluation of Clinically Relevant Drug-Drug Interactions and Population Pharmacokinetics of Darolutamide in Patients with Nonmetastatic Castration-Resistant Prostate Cancer: Results of Pre-Specified and Post Hoc Analyses of the Phase III ARAMIS Trial

BACKGROUND

Darolutamide, an androgen receptor antagonist with a distinct molecular structure, significantly prolonged metastasis-free survival versus placebo in the phase III ARAMIS study in men with nonmetastatic castration-resistant prostate cancer (nmCRPC). In this population, polypharmacy for age-related comorbidities is common and may increase drug-drug interaction (DDI) risks. Preclinical/phase I study data suggest darolutamide has a low DDI potential-other than breast cancer resistance protein/organic anion transporter protein substrates (e.g., statins), no clinically relevant effect on comedications is expected.

OBJECTIVE

Our objective was to evaluate the effect of commonly administered drugs on the pharmacokinetics of darolutamide and the effect of comedications potentially affected by darolutamide on safety in patients with nmCRPC.

PATIENTS AND METHODS

Comorbidities and comedication use in the 1509 ARAMIS participants treated with darolutamide 600 mg twice daily or placebo were assessed. A population pharmacokinetic analysis evaluated whether comedications affected the pharmacokinetics of darolutamide in a subset of 388 patients. A subgroup analysis of adverse events (AEs) in statin users versus nonusers was conducted.

RESULTS

Most participants (median age 74 years) had at least one comorbidity (98.4% in both arms) and used at least one comedication (98.7% with darolutamide vs. 98.0% with placebo); these were similar across study arms. Despite frequent use of comedications with DDI potential, no significant effects on darolutamide pharmacokinetics were identified. Comedications included lipid-modifying agents (34.5%), β-blockers (29.7%), antithrombotics (42.8%), and systemic antibiotics (26.9%). AE incidence was similar across study arms in statin users and nonusers. Study limitations include the small sample size for sub-analyses.

CONCLUSIONS

These analyses suggest the pharmacokinetic profile of darolutamide is not affected by a number of commonly administered drugs in patients with nmCRPC. Although pharmacokinetic data have indicated that darolutamide has the potential to interact with rosuvastatin, used to assess DDI in these studies, this finding did not seem to translate into increased AEs due to statin use in the ARAMIS trial. Clinicaltrials.gov identifier: NCT02200614.

[From Einstein's Quantum Theory to modern laser therapy. The history of lasers in dermatology and aesthetic medicine]

Laser technology has considerably expanded therapeutic modalities in dermatology and aesthetic medicine. In addition, lasers have broadened the spectrum of diagnostic and therapeutic options in many other medical fields. Dermatologists, especially Dr. Leon Goldman, played an important role in the evolution and use of medical lasers. There was a long way from the concept of stimulated emission as the fundamental idea of laser technology by Albert Einstein in 1917 to the practical use of the laser today. We review the development of laser technology from the early days through the latest advances.

Significant localized reduction in cerebral blood flow (CBF) in regions relevant to cognitive function with enzalutamide (ENZA) compared to darolutamide (DARO) and placebo (PBO) in healthy volunteers

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Background: DARO is an oral androgen receptor antagonist with a unique structure and a low blood–brain barrier penetrance noted in rodents. Here we compare CBF following administration of DARO, ENZA, and PBO using arterial spin labelled magnetic resonance imaging (ASL-MRI) in humans. Methods: This phase I, randomized, PBO-controlled, 3-period crossover study investigated drug-induced changes in CBF for brain grey matter and for specific regions related to cognitive function in healthy males (age 19–44). Twenty-three participants received a single oral dose of DARO, ENZA, or PBO at 6-week intervals at similar unbound concentrations . An ASL-MRI scan was performed ~4 hours after each dose. Blood samples for drug analysis and physiological measures were collected prior to drug administration and immediately post-scan. ASL data were preprocessed and statistical parametric modelling was used for treatment comparisons (paired t-tests). Whole-brain results were considered significant after correction for multiple comparisons. A linear mixed effects model was used for predetermined region of interest (ROI) analysis, with physiological parameters as nuisance regressors. Results: Drug-concentration data confirmed similar unbound exposure during MRI scans and a complete washout between treatments. No unexpected safety concerns were noted in the study. Whole-brain analysis showed a significant localized 5.2% reduction in CBF for ENZA in temporo-occipital cortices but no significant CBF reduction with DARO compared to PBO. A significant 5.9% localized reduction in CBF was measured for ENZA vs DARO. ROI analysis showed a significant reduction in CBF for ENZA vs PBO (p = 0.045) and for ENZA vs DARO (p = 0.037) in the left and right dorsolateral prefrontal cortices, respectively. A significant reduction was noted in CBF for ENZA vs PBO in right amygdala (p = 0.047). Conclusions: Compared to PBO and DARO, significant localized reductions in CBF were noted for ENZA. These results may be relevant to cognitive function (executive function, memory, and anxiety) with extended treatment and warrant further investigation. Clinical trial information: NCT03704519.

[Diffused traumatic dirt and decorative tattooing. Removal by Q-switched lasers]

BACKGROUND AND OBJECTIVE

Pigment fanning or spread is one complication of decorative tattooing, but is also seen after traumatic tattoos. The reason for this spreading remains unclear. While excision of the diffused pigment was previously considered the treatment of choice, today destruction of the pigment with Q-switched laser systems is the therapy with the highest efficiency and lowest rate of side effects. Therefore areas of pigment spread should be excised only in rare exceptional cases.

PATIENTS/METHODS

4 patients with pigment fanning after permanent make up and traumatic tattooing of the periorbital region were treated with the Q-switched ruby (694 nm) and Q-switched Nd:YAG (1064 nm) lasers.

RESULTS

All patients showed a significant (70-80%) clearance of the spread pigment; two had complete clearing. Side effects such as hyper- or hypopigmentation, scarring or ink darkening were not seen.

CONCLUSIONS

The Q-switched ruby- and Q-switched Nd:YAG-lasers are a therapeutic modality for pigment fanning with high efficiency and low rate of side effects. Attempts of explanation for pigment spread after tattoos are given, but further histological and electron microscopical investigations are needed to find the pathogenetic mechanism.

Drug-drug interaction (DDI) of darolutamide with cytochrome P450 (CYP) and P-glycoprotein (P-gp) substrates: Results from clinical and in vitro studies

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Background: Maintaining quality of survival, by delaying disease progression and minimizing therapy burden, is critical for patients and has been evaluated in the pivotal phase III ARAMIS study in patients with non-metastatic castration-resistant prostate cancer. Due to comorbidity, elderly men often receive multiple comedications, including CYP and P-gp substrates, eg, simvastatin and digoxin. Enzalutamide and apalutamide, approved androgen receptor (AR) inhibitors, are strong CYP3A4 inducers and thus have potential for CYP-mediated DDIs. The effect of darolutamide, a structurally unique AR antagonist, on CYP activity ( in vitro and in vivo) and P-gp activity ( in vivo) was assessed. Methods: Inhibition of CYP isoforms by Daro was investigated in human liver microsomes using standard substrates. In addition, CYP and P-gp activity during darolutamide treatment was studied in a phase I trial of 15 healthy men who received 75 mg dabigatran etexilate (DABE, P-gp substrate) + 1 mg midazolam (MDZ, CYP3A4 substrate) once followed by 600 mg darolutamide (two 300 mg tablets) twice daily (BID) given with food for 9 days. On day 9, darolutamide was concomitantly administered with a single dose of 75 mg DABE + 1 mg MDZ. Results: Based on in vitro data, no clinically relevant inhibition of CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, or 3A4 by darolutamide is expected. In 13 evaluable subjects in the phase I study, concomitant darolutamide reduced MDZ Cmax by ~32% and AUC by ~29% vs MDZ alone. Concomitant darolutamide reduced non-conjugated dabigatran Cmax by 16% and AUC by 9% vs DABE alone. The observed treatment-emergent adverse events were consistent with the known safety profile of darolutamide. No new safety risks were revealed by co-administration of darolutamide and DABE or MDZ. Safety data for patients in ARAMIS who received darolutamide, including those with concomitant CYP or P-gp substrates, will be presented. Conclusions: Darolutamide showed only weak effects or none on P-gp, CYP3A4, or any other relevant CYP enzyme. Thus, darolutamide is not expected to cause any clinically relevant DDI with CYP or P-gp substrates, minimizing complications of polypharmacy. Clinical trial information: NCT03237416.

Phase 1, open-label, dose-escalation study of sorafenib in combination with eribulin in patients with advanced, metastatic, or refractory solid tumors

Combining sorafenib and eribulin mesylate may provide synergistic antitumor activities with limited overlapping toxicities. This phase 1b, open-label, dose-escalation study evaluated safety, pharmacokinetics, maximum tolerated dose/recommended phase 2 dose (MTD/RP2D), and preliminary efficacy of sorafenib plus standard-dose eribulin mesylate in patients with advanced, metastatic, or refractory tumors. Patients received sorafenib 200 mg twice daily (BID; n = 5), 600 mg/day (n = 8), and 400 mg BID (MTD; n = 27). Dose-limiting toxicities were increased alanine aminotransferase and acute coronary syndrome (both grade 3) in the 400-mg BID dose-escalation and expansion cohorts, respectively. No significant increase in mean QTcF duration was observed with eribulin plus sorafenib versus eribulin alone; there were no drug-drug interactions. Five patients achieved partial response; 16 achieved stable disease. The combination of sorafenib and eribulin mesylate presented no unexpected safety concerns and no significant impact on QT/QTc intervals or drug-drug interactions. Sorafenib 400 mg BID plus standard-dose eribulin is the RP2D.