Pharmacokinetic Aspects of the Two Novel Oral Drugs Used for Metastatic Castration-Resistant Prostate Cancer: Abiraterone Acetate and Enzalutamide

Clinically significant drug-drug interactions involving opioid analgesics used for pain treatment in patients with cancer: update of a systematic review

INTRODUCTION

Drug-drug interactions (DDIs) are among factors that may affect the efficacy and safety of opioid treatment. Data on clinically manifested DDIs are scarse, and recommendations that might guide physicians are presently lacking. The aim of this study was to update a systematic review (2015) on studies reporting clinically significant DDIs involving opioids used for pain treatment in adult patients with cancer.

METHODS

Systematic literature searches in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials from the start of the databases through 18 September 2023.

RESULTS

Of the 1968 retrieved papers, 16 were included in the final analysis, together with five papers identified through hand-searching of reference lists. Nineteen publications were case reports or case series. Nine, sixteen, and eight patients presented adverse effects from opioids, impaired pain control, or opioid withdrawal, respectively. The main mechanisms underlying DDIs were alteration of cytochrome P450 3A4 activity and pharmacodynamic antagonism resulting from concurrent use of an opioid analgesic and a peripheral mu-opioid receptor antagonist (PAMORA).

CONCLUSION

Knowledge about clinically significant DDIs associated with opioids in cancer patients is currently mostly based upon case reports. These cases give information about drug combinations that should be recognized as potentially harmful by physicians prescribing opioids.

PROSPERO ID

CRD42023481103.

Nanoparticles with curcumin and piperine modulate steroid biosynthesis in prostate cancer

Endogenous androgens are pivotal in the development and progression of prostate cancer (PC). We investigated nanoparticle formulations of curcumin and piperine in modulating steroidogenesis within PC cells. Using multiple PC cell lines (LNCaP, VCaP, DU145 and PC3) we studied the effects of curcumin, piperine, and their nanoparticle formulations-curcumin nanoparticles, piperine nanoparticles, and curcumin-piperine nanoparticles (CPN)-on cell viability, migration, and steroid biosynthesis. Curcumin and its nanoparticle formulations significantly reduced cell viability in PC cells, with curcumin-piperine nanoparticles showing the highest efficacy. These treatments also inhibited cell migration, with CPN exhibiting the most pronounced effect. In assays for steroid biosynthesis, curcumin, and its nanoparticle formulations, as well as piperine and its nanoparticles, selectively inhibited 17α-hydroxylase and 17,20-lyase activities of cytochrome P450 17A1 (CYP17A1). Abiraterone, a CYP17A1 inhibitor, displayed a broader inhibition of steroid metabolism including cytochrome P450 21-hydroxylase activity, whereas curcumin and piperine provided a more targeted inhibition profile. Analysis of steroid metabolites by liquid chromatography-mass spectrometry revealed that CPN caused significant reduction of androstenedione and cortisol, suggesting potential synergistic effects. In conclusion, nanoformulations co-loaded with curcumin and piperine offer an effective approach to targeting steroidogenesis and could be promising candidates for therapies aimed at managing androgen-dependent PC.

Case Report: Abiraterone in brain metastases from prostate cancer

Background

Prostate carcinoma (PC) is the most common cancer in men worldwide. However, brain metastases (BM) from prostate cancer are extremely rare events, usually in the later course of the disease. There is no established standard of care treatment for this situation. The efficacy of androgen synthesis inhibitor abiraterone in BM from PC is unknown.

Case

We herein report the case of an 83-year-old patient with metastatic hormone-sensitive PC who had multiple BM at primary diagnosis, clinically manifesting with dizziness, ataxia, and unsteady gait. Combination of abiraterone and androgen deprivation therapy showed exceptional sustained cerebral tumor response. After 12 months of treatment, the patient is asymptomatic with an excellent performance status.

Conclusion

Symptomatic BM from PC is a rarity but can show sustained response to abiraterone and androgen deprivation therapy. After comprehensive literature search, there is no comparable case published to date.

Drug-drug interactions in HIV-infected patients receiving chemotherapy

INTRODUCTION

Coadministration of antiretrovirals and anti-cancer medications may present many complex clinical scenarios. This is characterized by the potential for drug-drug interactions (DDIs) and the challenges that arise in patient management. In this article, we investigate the potential for DDIs between antiretrovirals, including protease inhibitors (PIs), non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs), integrase strand transfer inhibitors (INSTIs), and anti-cancer medications.

AREAS COVERED

PubMed, Google Scholar, and Clinicaltrials.gov were searched for relevant articles in April 2024. Our review highlights PIs and NNRTIs as particularly prone to DDIs with anticancer agents, with implications for efficacy and toxicity of concomitant cancer therapy. We explain the mechanisms for interactions, emphasizing the significance of pharmacokinetic effects and enzyme induction or inhibition. We discuss clinical challenges encountered in the management of patients receiving combined ART and cancer therapy regimens.

EXPERT OPINION

Data are lacking for potential DDIs between antiretroviral and anti-cancer agents. While some interactions are documented, others are theoretical and based on the pharmacokinetic properties of the medications. Awareness of these interactions, inter-collaborative care between healthcare providers, and standardized treatment guidelines are all crucial for achieving optimal treatment outcomes and ensuring the well-being of patients with HIV/AIDS and cancer comorbidities.

DoE-assisted HPLC method development and validation of enzalutamide and repaglinide in rat plasma

Aim: A simple and rapid HPLC technique was developed and validated to simultaneously estimate enzalutamide (ENZ) and repaglinide (REP) in rat plasma.Methods: In silico predictions using DDinter and DDI-Pred indicated possible drug-drug interactions between ENZ and REP. A central composite design was used to identify factors influencing the separation of the drugs. Interactions between chromatographic parameters were studied through 51 experiments, followed by illustration with three-dimensional response surface plots. The four factors optimized for the separation of the two drugs are column temperature (A), % organic strength (B), pH (C) and column type (D).Results: Plate count(R1), tailing factor (R2) and resolution (R3) responses in the experimental design were analyzed with the favorable chromatographic conditions predicted to be 0.1% formic acid and acetonitrile as mobile phases on a Phenomenex C18 LC column (250 × 4.6 mm, 5 μm). The method was applied to estimate the drugs in rat plasma using a simple protein-precipitation step and found to be linear, accurate and precise within the ranges of 0.5-16 and 5-50 μg/ml for ENZ and REP, respectively.Conclusion: The optimized method can be used in future bioanalytical workflow for drug quantification and drug-drug compatible studies.

Pharmacokinetic Interactions Between Abiraterone, Apalutamide, Darolutamide or Enzalutamide and Antithrombotic Drugs: Prediction of Clinical Events and Review of Pharmacological Information

PURPOSE

Abiraterone, apalutamide, darolutamide and enzalutamide are second-generation hormone therapies used for advanced prostate cancer; the majority of patients receiving these treatments are elderly, poly-medicated patients. Since their first market authorizations, their pharmacokinetic (PK) characteristics are increasingly well known. A potential risk of drug-drug interaction (DDI), especially with cardiovascular drugs, needs to be considered. In the case of antithrombotics, treatment imbalance can lead to severe consequences.

OBJECTIVES

To describe PK profiles of hormone therapies and antithrombotics and to predict DDIs and potentially related clinical events.

METHODS

PK profiles (CYP450 and P-gp substrate, inducer or inhibitor) are described by cross-referencing data sources (summary of product characteristics, European public assessment reports, PubMed database, Micromedex®, etc.); a description of the potential interactions with anti-cancer drugs for each DDI and related clinical events is provided. We discuss management recommendations, including those set out in international guidelines.

RESULTS

Antithrombotics are mainly metabolized by CYP 2C9, 2C19 or 3A4. For abiraterone (CYP 2C8, 2D6 inhibitor) and darolutamide (CYP 3A4 inducer), no interaction was identified with antithrombotics. For apalutamide (CYP 2C9, 2C19, 3A4 and P-gp inducer) and enzalutamide (CYP 2C9, 2C19, 3A4 inducer and P-gp inhibitor), several PK interactions were identified with antithrombotics, which could lead to various clinical events (haemorrhage or thromboembolism).

CONCLUSION

Numerous interactions are expected between enzalutamide or apalutamide and antithrombotics, for which management should be deployed on a case-by-case basis. PK and pharmaco-epidemiological studies could shed light on whether or not there are clinically significant events related to DDIs with antithrombotics.

Synthesis and Biological Evaluation of Methoxypolyethylene-Glycol-Substituted Abiraterone Derivatives as Potential Antiprostate Cancer Agents

Globally, prostate cancer is the most commonly diagnosed tumor and a cause of death in older men. Abiraterone, an orally administered irreversible CYP17 inhibitor, is employed to treat prostate cancer. However, abiraterone has several clinical limitations, such as poor water solubility, low dissolution rate, low bioavailability, and toxic side effects in the liver and kidney. Therefore, there is a need to identify high-efficiency and low-toxicity water-soluble abiraterone derivatives. In this work, we aimed to design and synthesize a series of abiraterone derivatives by methoxypoly(ethylene glycol) (mPEG) modification. Their antitumor activities and toxicology were analyzed in vitro and in vivo. The most potent compound, 2e, retained the principle of action on the CYP17 enzyme target and significantly improved the abiraterone water solubility, cell permeability, and blood safety. No significant abnormalities were observed in toxicology. mPEG-modification significantly improved abiraterone's antitumor activity and efficiency while reducing the associated toxic effects. The finding will provide a theoretical basis for future clinical application of mPEG-modified abiraterone.

Intra-individual Dose Escalation of Abiraterone According to Its Plasma Exposure in Patients with Progressive Metastatic Castration-Resistant Prostate Cancer: Results of the OPTIMABI Trial

BACKGROUND AND OBJECTIVE

Trough abiraterone concentration (ABI Cmin) of 8.4 ng/mL has been identified as an appropriate efficacy threshold in patients treated for metastatic castration-resistant prostate cancer (mCRPC). The aim of the phase II OPTIMABI study was to evaluate the efficacy of pharmacokinetics (PK)-guided dose escalation of abiraterone acetate (AA) in underexposed patients with mCRPC with early tumour progression.

METHODS

This multicentre, non-randomised study consisted of two sequential steps. In step 1, all patients started treatment with 1000 mg of AA once daily. Abiraterone Cmin was measured 22-26 h after the last dose intake each month during the first 12 weeks of treatment. In step 2, underexposed patients (Cmin < 8.4 ng/mL) with tumour progression within the first 6 months of treatment were enrolled and received AA 1000 mg twice daily. The primary endpoint was the rate of non-progression at 12 weeks after the dose doubling. During step 1, adherence to ABI treatment was assessed using the Girerd self-reported questionnaire. A post-hoc analysis of pharmacokinetic (PK) data was conducted using Bayesian estimation of Cmin from samples collected outside the sampling guidelines (22-26 h).

RESULTS

In the intention-to-treat analysis (ITT), 81 patients were included in step 1. In all, 21 (26%) patients were underexposed in step 1, and 8 of them (38%) experienced tumour progression within the first 6 months. A total of 71 patients (88%) completed the Girerd self-reported questionnaire. Of the patients, 62% had a score of 0, and 38% had a score of 1 or 2 (minimal compliance failure), without a significant difference in mean ABI Cmin in the two groups. Four patients were enrolled in step 2, and all reached the exposure target (Cmin > 8.4 ng/mL) after doubling the dose, but none met the primary endpoint. In the post-hoc analysis of PK data, 32 patients (39%) were underexposed, and ABI Cmin was independently associated with worse progression-free survival [hazard ratio (HR) 2.50, 95% confidence interval (CI) 1.07-5.81; p = 0.03], in contrast to the ITT analysis.

CONCLUSION

The ITT and per-protocol analyses showed no statistical association between ABI underexposure and an increased risk of early tumour progression in patients with mCRPC, while the Bayesian estimator showed an association. However, other strategies than dose escalation at the time of progression need to be evaluated. Treatment adherence appeared to be uniformly good in the present study. Finally, the use of a Bayesian approach to recover samples collected outside the predefined blood collection time window could benefit the conduct of clinical trials based on drug monitoring. OPTIMABI trial is registered as National Clinical Trial number NCT03458247, with the EudraCT number 2017-000560-15).

New-generation androgen receptor signaling inhibitors (ARSIs) in metastatic hormone-sensitive prostate cancer (mHSPC): pharmacokinetics, drug-drug interactions (DDIs), and clinical impact

INTRODUCTION

The therapeutic scenario of metastatic hormone-sensitive prostate cancer (mHSPC) has dramatically changed in recent years, with the approval of new-generation Androgen Receptor Signaling Inhibitors (ARSIs), in combination with the androgen deprivation therapy (ADT), which was the previous standard of care. Despite showing a similar clinical efficacy, ARSIs, all of which are administered orally, are different in terms of pharmacokinetic and drug-drug interactions (DDIs).

AREAS COVERED

This review covers the main pharmacokinetic characteristics of ARSIs that have been approved for the first-line therapy of mHSPC patients, underlying the differences among these molecules and focusing on the known or possible interactions with other drugs. Full-text articles and abstracts were searched in PubMed.

EXPERT OPINION

Since prostate cancer occurs mainly in older age, comorbidities and the consequent polypharmacy increase the DDI risk in mHSPC patients who are candidates for ARSI. Waiting for new therapeutic options, in the absence of direct comparisons, pharmacokinetic knowledge is essential to guide clinicians in prescribing ARSI in this setting.

Long-Term Pharmacokinetic Follow-Up of Abiraterone Acetate in Patients with Metastatic Castration-Resistant Prostate Cancer

This ABIGENE pharmacokinetic (PK) study sought mainly to characterize the unchanged drug PK during long-term abiraterone acetate (AA) administration in advanced prostate cancer patients (81 patients). It was observed that individual AA concentrations remained constant over treatment time, with no noticeable changes during repeated long-term drug administration for up to 120 days. There was no correlation between AA concentrations and survival outcomes. However, a significant association between higher AA concentrations and better clinical benefit was observed (p = 0.041). The safety data did not correlate with the AA PK data. A significant positive correlation (r = 0.40, p < 0.001) was observed between mean AA concentration and patient age: the older the patient, the higher the AA concentration. Patient age was found to impact steady-state AA concentration: the older the patient, the higher the mean AA concentration. Altogether, these data may help to guide future research and clinical trials in order to maximize the benefits of AA metastatic castration-resistant prostate cancer patients.

Cost-effectiveness and budget impact analysis of enzalutamide in comparison to abiraterone in treatment of metastatic prostate cancer resistant to castration in Iran

INTRODUCTION

In recent years, enzalutamide and abiraterone have been widely used as treatments for metastatic castration-resistant prostate cancer (mCRPC). However, the cost-effectiveness of these drugs in Iran is unknown. This study evaluated the cost-effectiveness of enzalutamide for the treatment of metastatic prostate cancer resistant to castration in Iran.

METHODS

A 3-state Markov model was developed to evaluate the cost-effectiveness of enzalutamide and abiraterone from a social perspective over 10 years. The clinical inputs were obtained from the meta-analysis studies. The direct medical costs were obtained from the tariffs of the healthcare system, while the direct non-medical and indirect costs were collected from the patients. The data of utilities were derived from the literature. In addition, sensitivity analyses were conducted to assess the uncertainties.

RESULTS

Compared with Abiraterone, enzalutamide was associated with a high incremental cost-effectiveness ratio (ICER) of $6,260 per QALY gained. According to the one-way sensitivity analysis, ICER was most heavily influenced by the prices of enzalutamide and Abiraterone, non-medical costs, and indirect costs. Regardless of the variation, enzalutamide remained cost-effective. The budget impact analysis of enzalutamide in the health system during 5 years was estimated at $6,362,127.

CONCLUSIONS

At current prices, adding enzalutamide to pharmaceutical lists represents the cost-effective use of the healthcare resources in Iran for the treatment of metastatic castration-resistant prostate cancer.

A new method to quantify the effect of co-medication on the efficacy of abiraterone in metastatic castration-resistant prostate cancer patients

Background and Objective: Patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate (AA) have co-morbidities treated with different drugs. The aim was to quantify the potential effect of co-medications on AA treatment duration (TD) and overall survival (OS). Methods: A new parameter, called "individual drug score" (IDS) was calculated by summing the "drug score"-s (DS) of all co-medications for each patient. The DS was determined by quantifying the effect of a given co-drug on enzymes involved in steroidogenesis and metabolism of AA. The correlation between log (IDS) and TD was tested by non-linear curve fit. Kaplan-Meier method and multivariate Cox regression was used for analysis of TD and OS. Results: The IDS and TD of AA+prednisolone showed a dose-response correlation (n = 166). Patients with high IDS had significantly longer TD and OS (p <0.001). In multivariate analysis IDS proved to be an independent marker of TD and OS. The same analysis was performed in a separate group of 81 patients receiving AA+dexamethasone treatment. The previously observed relationships were observed again between IDS and TD or OS. After combining the AA+prednisolone and AA+dexamethasone groups, analysis of the IDS composition showed that patients in the high IDS group not only used more drugs (p <0.001), but their drugs also had a higher mean DS (p = 0.001). Conclusion: The more co-drugs with high DS, the longer the duration of AA treatment and OS, emphasizing the need for careful co-medication planning in patients with mCRPC treated with AA. It is recommended that, where possible, co-medication should be modified to minimize the number of drugs with negative DS and increase the number of drugs with high DS. Our new model can presumably be adapted to other drugs and other cancer types (or other diseases).

The Complexity of Treatments and the Multidisciplinary Team-A Rare Case of Long-Term Progression-Free Survival in Prostate Cancer until Development of Liver and Brain Metastases

INTRODUCTION

Prostate cancer has no initial clinical manifestation in the case of brain metastases since they are asymptomatic at first. This is why there is a high risk for clinicians to overlook these lesions, and they are often confused with other diseases. With all the improvements in diagnostic technological methods, which allow the early detection of lesions, and the progress in terms of systemic therapy associated with increased survival, an increase in incidence has also been noticed.

MATERIALS AND METHODS

We report the case of a 64-year-old patient who presented himself to the Oncology Department of "St. Luca" Chronic Disease Hospital in Bucharest in November 2011 and received the following diagnosis: biopsied prostate neoplasm, local-regionally advanced, pelvic lymph node metastases.

RESULTS

After receiving complex oncological treatment, this patient represents a rare case of long-term progression-free survival (15 years).

DISCUSSIONS

This case has some particularities. According to the literature data, survival with metastatic prostate cancer is approximately 21 months, and cerebral metastases are found in only 2% of prostate cancer cases. This case is one of the few cases in the specialty literature that benefited from all therapeutic sequences; namely, total androgenic blockade, docetaxel, abiraterone, enzalutamide, and cabazitaxel.

CONCLUSIONS

Brain metastases are an unfavorable prognostic factor in prostate cancer. The therapeutic options developed in recent years allow the improvement of survival.

Clinical Pharmacokinetics and Pharmacodynamics of the Next Generation Androgen Receptor Inhibitor-Darolutamide

Darolutamide is a next-generation androgen receptor signaling inhibitor (ARSI) currently approved for the treatment of nonmetastatic castration-resistant prostate cancer (nmCRPC) and metastatic hormone sensitive prostate cancer (mHSPC). Studies suggest that darolutamide also has the potential to be used to treat other stages of prostate cancer (PC), suggesting that its indications will broaden in the near future. Since ARSIs show similar efficacy for the treatment of PC, pharmacokinetic properties of these drugs and patient characteristics could help physicians decide which drug to select. This review provides an overview of the pharmacokinetic and pharmacodynamic properties of darolutamide. One of the most important pharmacological advantages of darolutamide is its low brain distribution and therefore limited seizure potential and central nervous system adverse effects. In addition, darolutamide has little drug-drug interaction potential and is unlikely to alter the exposure of other cytochrome P450 or P-glycoprotein substrates. Nevertheless, it may significantly increase the exposure of breast cancer resistant protein (BCRP) substrates. The limited solubility and bioavailability of darolutamide increases when taken together with food, regardless of the fat content. Darolutamide is excessively metabolized by oxidation and glucuronidation and excreted in the urine and feces. For this reason, dose reduction is required in patients with moderate and severe renal or severe hepatic impairment. Although no exposure-response relationship was observed with darolutamide, less advanced stages of PC showed better PSA response on treatment. Overall, darolutamide has some advantageous pharmacological properties that may lead to its preferred use, when broader registered, in selected patients across different disease stages.

Randomized Phase III Study of Enzalutamide Compared With Enzalutamide Plus Abiraterone for Metastatic Castration-Resistant Prostate Cancer (Alliance A031201 Trial)

PURPOSE

Enzalutamide and abiraterone both target androgen receptor signaling but via different mechanisms. The mechanism of action of one drug may counteract the resistance pathways of the other. We sought to determine whether the addition of abiraterone acetate and prednisone (AAP) to enzalutamide prolongs overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) in the first-line setting.

PATIENTS AND METHODS

Men with untreated mCRPC were randomly assigned (1:1) to receive first-line enzalutamide with or without AAP. The primary end point was OS. Toxicity, prostate-specific antigen declines, pharmacokinetics, and radiographic progression-free survival (rPFS) were also examined. Data were analyzed using an intent-to-treat approach. The Kaplan-Meier estimate and the stratified log-rank statistic were used to compare OS between treatments.

RESULTS

In total, 1,311 patients were randomly assigned: 657 to enzalutamide and 654 to enzalutamide plus AAP. OS was not statistically different between the two arms (median, 32.7 [95% CI, 30.5 to 35.4] months for enzalutamide v 34.2 [95% CI, 31.4 to 37.3] months for enzalutamide and AAP; hazard ratio [HR], 0.89; one-sided P = .03; boundary nominal significance level = .02). rPFS was longer in the combination arm (median rPFS, 21.3 [95% CI, 19.4 to 22.9] months for enzalutamide v 24.3 [95% CI, 22.3 to 26.7] months for enzalutamide and AAP; HR, 0.86; two-sided P = .02). However, pharmacokinetic clearance of abiraterone was 2.2- to 2.9-fold higher when administered with enzalutamide, compared with clearance values for abiraterone alone.

CONCLUSION

The addition of AAP to enzalutamide for first-line treatment of mCRPC was not associated with a statistically significant benefit in OS. Drug-drug interactions between the two agents resulting in increased abiraterone clearance may partly account for this result, although these interactions did not prevent the combination regimen from having more nonhematologic toxicity.

Frailty and survival among veterans treated with abiraterone or enzalutamide for metastatic castration-resistant prostate cancer

INTRODUCTION

Abiraterone and enzalutamide are treatments for metastatic castration-resistant prostate cancer (mCRPC). Due to a lack of head-to-head trials, they are prescribed interchangeably. However, the drugs have different pharmacokinetics and thus may have differing efficacy and adverse effects influenced by patient functional status and comorbid diseases. Additionally, mCRPC mainly affects older adults and since the prevalence of frailty increases with age, frailty is an important patient factor to consider in personalizing drug selection.

MATERIALS AND METHODS

We conducted a retrospective observational study of US veterans treated with abiraterone or enzalutamide for mCRPC from September 2014 to June 2017. Frailty was assessed using the Veterans Affairs Frailty Index (VA-FI), which utilizes administrative codes to assign a standardized frailty score. Patients were categorized as frail if VA-FI scores were > 0.2. The primary outcome was difference in overall survival (OS) between the two treatment groups. Cox regression modeling and propensity score matching was used to compare between abiraterone and enzalutamide treatments.

RESULTS

We identified 5,822 veterans, 57% of whom were initially treated with abiraterone and 43% with enzalutamide. Frail patients (n = 2,314; 39.7%) were older, with a mean age of 76.1 versus 74.9 years in the non-frail group (n = 3,508; 60.3%, p < 0.001) and had shorter OS compared to non-frail patients regardless of treatment group (18.5 vs. 26.6 months, p < 0.001). Among non-frail patients there was no significant difference in OS between abiraterone and enzalutamide treatment (27.7 vs 26.1 months, p = 0.07). However, frail patients treated with enzalutamide versus abiraterone had improved OS (20.7 vs 17.2 months, p < 0.001). In a propensity score matched analysis of frail patients (n = 2,070), enzalutamide was associated with greater median OS (24.1 vs 20.9 months, p < 0.001). In patients with dementia, enzalutamide was associated with longer OS (19.4 vs. 16.6 months, p = 0.003).

DISCUSSION

In this study of 5822 US veterans with mCRPC, treatment with enzalutamide was associated with improved OS compared to abiraterone among frail veterans and veterans with dementia, but not among non-frail veterans. Future studies should evaluate interactions between frailty and cancer treatments to optimize selection of therapy among frail adults.

Non-steroidal CYP17A1 Inhibitors: Discovery and Assessment

CYP17A1 is an enzyme that plays a major role in steroidogenesis and is critically involved in the biosynthesis of steroid hormones. Therefore, it remains an attractive target in several serious hormone-dependent cancer diseases, such as prostate cancer and breast cancer. The medicinal chemistry community has been committed to the discovery and development of CYP17A1 inhibitors for many years, particularly for the treatment of castration-resistant prostate cancer. The current Perspective reflects upon the discovery and evaluation of non-steroidal CYP17A1 inhibitors from a medicinal chemistry angle. Emphasis is placed on the structural aspects of the target, key learnings from the presented chemotypes, and design guidelines for future inhibitors.

Metabolism-Guided Selective Androgen Receptor Antagonists: Design, Synthesis, and Biological Evaluation for Activity against Enzalutamide-Resistant Prostate Cancer

A major challenge for new drug discovery in the area of androgen receptor (AR) antagonists lies in predicting the druggable properties that will enable small molecules to retain their potency and stability during further studies in vitro and in vivo. Indole (compound 8) is a first-in-class AR antagonist with very high potency (IC50 = 0.085 μM) but is metabolically unstable. During the metabolic studies described herein, we synthesized new small molecules that exhibit significantly improved stability while retaining potent antagonistic activity for an AR. This structure-activity relationship (SAR) study of more than 50 compounds classified with three classes (Class I, II, and III) and discovered two compounds (32c and 35i) that are potent AR antagonists (e.g., IC50 = 0.021 μM, T1/2 = 120 min for compound 35i). The new antagonists exhibited improved in vivo pharmacokinetics (PK) with high efficacy antiandrogen activity in Hershberger and antiandrogen Enz-Res tumor xenograft models that overexpress AR (LNCaP-AR).

Allogeneic stem cell transplantation in patients with a prior history of prostate cancer

A retrospective analysis of 25 patients with a history of prostate cancer (PC) who subsequently underwent allogeneic hematopoietic cell transplantation (HCT) for treatment of a hematologic malignancy was performed. Median patient age was 66.7 years. Median duration from the diagnosis of PC to HCT was 4.2 years. Twenty-three patients had Gleason group 1 or 2 disease. Therapy included prostatectomy (n = 13) and external beam or brachytherapy (n = 9). Hematologic diagnoses included both myeloid (n = 15) and lymphoid neoplasms (n = 10). Twenty-four patients received either a nonmyeloablative or reduced intensity conditioning regimen. GVHD prophylaxis included a calcineurin inhibitor and mycophenolate mofetil ± sirolimus. Twenty patients had HLA-matched sibling or HLA-matched unrelated donors; five patients had HLA-mismatched donors. Eleven patients are alive, and 14 have died. Median survival was 2.5 years (range, .02-12.6 years). The major cause of death was hematologic relapse. Only one patient had evidence of recurrent PC, occurring 1.5 years posttransplant. In carefully selected patients with a prior history of PC, there was no evidence of rapid recurrence of the solid tumor (ST) after HCT. PC patients who are in remission from their ST or have control of their disease on therapy should be considered eligible for HCT.

Impact of trough abiraterone level on adverse events in patients with prostate cancer treated with abiraterone acetate

PURPOSE

We assessed the impact of plasma trough concentrations of abiraterone (ABI) and its metabolite Δ4-abiraterone (D4A) and related polymorphisms on adverse events (AEs) in patients with metastatic prostate cancer who received abiraterone acetate (AA).

METHODS

This prospective study enrolled patients with advanced prostate cancer treated with AA between 2016 and 2021. Plasma trough concentrations of ABI and D4A were measured using high-performance liquid chromatography. The impact of HSD3B1 rs1047303, SRD5A2 rs523349, and cytochrome P450 family 3A member 4 rs2242480 polymorphisms on plasma concentrations of ABI and D4A and the incidence of AEs were also assessed.

RESULTS

In 68 patients treated with AA, the median ABI and D4A concentrations were 18.1 and 0.94 ng/mL, respectively. The high plasma trough concentration of ABI (≥ 20.6 ng/mL) was significantly associated with the presence of any AE and its independent risk factor based on multivariable analysis (odds ratio, 7.20; 95% confidence interval (CI): 2.20-23.49). Additionally, a high plasma trough concentration of ABI was an independent risk factor of time to withdraw AA (hazard ratio, 4.89; 95% CI: 1.66-14.38). The risk alleles of three polymorphisms were not statistically associated with the ABI and D4A concentrations and the incidence of AEs.

CONCLUSIONS

The plasma trough concentration of ABI is associated with the presence of AEs and treatment failure after AA administration. ABI concentration monitoring may be useful in patients with prostate cancer who received AA.

Deep learning identifies explainable reasoning paths of mechanism of action for drug repurposing from multilayer biological network

The discovery and repurposing of drugs require a deep understanding of the mechanism of drug action (MODA). Existing computational methods mainly model MODA with the protein-protein interaction (PPI) network. However, the molecular interactions of drugs in the human body are far beyond PPIs. Additionally, the lack of interpretability of these models hinders their practicability. We propose an interpretable deep learning-based path-reasoning framework (iDPath) for drug discovery and repurposing by capturing MODA on by far the most comprehensive multilayer biological network consisting of the complex high-dimensional molecular interactions between genes, proteins and chemicals. Experiments show that iDPath outperforms state-of-the-art machine learning methods on a general drug repurposing task. Further investigations demonstrate that iDPath can identify explicit critical paths that are consistent with clinical evidence. To demonstrate the practical value of iDPath, we apply it to the identification of potential drugs for treating prostate cancer and hypertension. Results show that iDPath can discover new FDA-approved drugs. This research provides a novel interpretable artificial intelligence perspective on drug discovery.

Effects of the androgen receptor inhibitor enzalutamide on the pharmacokinetics of dolutegravir and tenofovir: a case report

ABSTRACT

Enzalutamide is an androgen receptor inhibitor used for the treatment of prostate cancer. Although enzalutamide causes a favorable adverse effect profile, it might cause drug-drug interactions with some antiretrovirals. No major differences on the main dolutegravir and tenofovir pharmokinetocs were observed in this case report when comparing baseline assessments with those following the introduction of enzalutamide, also when given at higher doses, in a 63-year-old male living with HIV and prostate cancer.

Biotransformation of Abiraterone Into Five Characteristic Metabolites by the Rat Gut Microbiota and Liver Microsomes

It is well known that the role of gut microbiota in drug metabolism, especially in oral difficult absorbable drugs. Understanding the gut microbiota could enable us to understand drugs in new ways. The purpose of the study was to investigate explore the metabolites of the anti-prostate cancer drug Abiraterone by examining gut microbiota metabolism and hepatic metabolism in vitro. In this study, five metabolites (M1, M2, M3, M4 and M5) of Abiraterone were discovered using LC/MSⁿ-IT-TOF. Four isomeric metabolites M1-M4 were found in liver microsome. M5 was found in the intestinal contents of Sprague-Dawley rats with a molecular weight of 388.31. Among them, M4 was found to be Abiraterone N-Oxide by comparison with the standard sample. After further comparing the metabolic behavior of Abiraterone in rat gut microbiota and liver microsomes, we delineated the possible metabolic pathways of Abiraterone. In conclusion, Abiraterone is metabolized specifically in liver microsomes and gut microbiota. This study can provide a theoretical basis for elucidating the metabolic mechanism of Abiraterone and guide its rational application in clinic.

Prostate Cancer Brain Metastasis: Review of a Rare Complication with Limited Treatment Options and Poor Prognosis

Brain metastases (BM) are perceived as a rare complication of prostate cancer associated with poor outcome. Due to limited published data, we conducted a literature review regarding incidence, clinical characteristics, treatment options, and outcomes of patients with prostate cancer BM. A literature analysis of the PubMed, MEDLINE, and EMBASE databases was performed for full-text published articles on patients diagnosed with BM from prostate cancer. Eligible studies included four or more patients. Twenty-seven publications were selected and analyzed. The sources of published patient cohorts were retrospective chart reviews, administrative healthcare databases, autopsy records, and case series. BM are rare, with an incidence of 1.14% across publications that mainly focus on intraparenchymal metastases. Synchronous visceral metastasis and rare histological prostate cancer subtypes are associated with an increased rate of BM. Many patients do not receive brain metastasis-directed local therapy and the median survival after BM diagnosis is poor, notably in patients with multiple BM, dural-based metastases, or leptomeningeal dissemination. Overall, prostate cancer BM are rare and associated with poor prognosis. Future research is needed to study the impact of novel prostate cancer therapeutics on BM incidence, to identify patients at risk of BM, and to characterize molecular treatment targets.

Effect of enzalutamide on PK of P-gp and BCRP substrates in cancer patients: CYP450 induction may not always predict overall effect on transporters

Drug‐drug interaction (DDI) is an important consideration for clinical decision making in prostate cancer treatment. The objective of this study was to evaluate the effect of enzalutamide, an oral androgen receptor inhibitor, on the pharmacokinetics (PK) of digoxin (P‐glycoprotein [P‐gp] probe substrate) and rosuvastatin (breast cancer resistance protein [BCRP] probe substrate) in men with metastatic castration‐resistant prostate cancer (mCRPC). This was a phase I, open‐label, fixed‐sequence, crossover study (NCT04094519). Eligible men with mCRPC received a single dose of transporter probe cocktail containing 0.25 mg digoxin and 10 mg rosuvastatin plus enzalutamide placebo‐to‐match on day 1. On day 8, patients started 160 mg enzalutamide once daily through day 71. On day 64, patients also received a single dose of the cocktail. The primary end points were digoxin and rosuvastatin plasma maximum concentration (C_max), area under the concentration‐time curve from the time of dosing to the last measurable concentration (AUC_last), and AUC from the time of dosing extrapolated to time infinity (AUC_inf). Secondary end points were enzalutamide and N‐desmethyl enzalutamide (metabolite) plasma C_max, AUC during a dosing interval, where tau is the length of the dosing interval (AUC_tau), and concentration immediately prior to dosing at multiple dosing (C_trough). When administered with enzalutamide, there was a 17% increase in C_max, 29% increase in AUC_last, and 33% increase in AUC_inf of plasma digoxin compared to digoxin alone, indicating that enzalutamide is a “mild” inhibitor of P‐gp. No PK interaction was observed between enzalutamide and rosuvastatin (BCRP probe substrate). The PK of enzalutamide and N‐desmethyl enzalutamide were in agreement with previously reported data. The potential for transporter‐mediated DDI between enzalutamide and digoxin and rosuvastatin is low in men with prostate cancer. Therefore, concomitant administration of enzalutamide with medications that are substrates for P‐gp and BCRP does not require dose adjustment in this patient population.

Development, Characterization, and Optimization of a Novel Abiraterone Acetate Formulation to Improve Biopharmaceutical Attributes Aided by Pharmacokinetic Modelling

Abiraterone acetate has very low bioavailability and drastic food effect to warrant a dosing regimen under fasting state only. Therefore, we aimed to develop and optimize a liquisolid compact formulation of abiraterone acetate to improve biopharmaceutical attributes aided by pharmacokinetic modelling and achieve dose reduction with no food effect on the formulation. Preliminary studies highlighted the importance of the selection of olive oil as a compatible vehicle. The pharmacokinetic model, integrated with gastrointestinal physiology, was used to predict fasted and fed state pharmacokinetic parameters. Optimization of the liquisolid formulation containing abiraterone acetate was carried at more than five times lower dose, i.e. 190 mg, compared to 1000 mg. A central composite design (CCD) was used to identify optimal levels of formulation factors, namely the amount of vehicle (olive oil), the amount of coating agent (silicon dioxide), and the amount of surfactant (polysorbate 80). Graphical optimization using the selected models in conjunction with maximization of the desirability was used to identify the optimized liquisolid formulation. The predicted pharmacokinetic parameters (fasted C_max 901.83 ng/mL, fasted AUC_inf 2723.82 ng·h/mL, fed C_max 1024.34 ng/mL, and fed AUC_inf 3041.83 ng·h/mL) of the optimized formulation were acceptable. Overall, the liquisolid compact formulation of abiraterone acetate was successfully developed and optimized. In vitro solubility and dissolution results aided by pharmacokinetic modelling also showed improved predicted bioavailability with greater than five times reduction in dose and elimination of food effect.

Oxymestane, a cytostatic steroid derivative of exemestane with greater antitumor activity in non-estrogen-dependent cell lines

A new promising steroid derivative of Exemestane (Exe), the drug used for the treatment of estrogen-dependent breast cancer, was synthesized and evaluated against a set of human cancer cell lines. The new compound (Oxymestane-D1, Oxy) was tested comparatively with Exe against colon (C2BBe1, WiDr), liver (HepG2, HuH-7), lung (A549, H1299) and prostate (LNCaP, PC3) human cancer cell lines. Likewise, its effect on human colon normal cells (CCD-841 CoN) and human normal fibroblast cells (HFF-1) was studied. The cytostatic activity of Oxy was also compared with that of the reference cytostatic drugs used in chemotherapy protocols, namely carboplatin, cisplatin, doxorubicin, epirubicin, etoposide, flutamide, 5-fluorouracil, irinotecan, oxaliplatin and sorafenib. In all cell lines tested, Oxy proved to be more powerful cytostatic than Exe. Additionally, the IC₅₀ at 72 h showed a three-fold activity greater than 5-fluorouracil in the WiDr cell line, twice as high as cisplatin for cell line A549 and five times higher than cisplatin for cell line H1299. Also, Oxy surprisingly revealed to induce DNA damage and inhibit the DNA damage response (DDR) proteins ATM, ATR, CHK1 and CHK2. The results obtained allow concluding that Oxy can be a promising anticancer agent to be used in chemotherapy protocols. Furthermore, its ability to inhibit crucial components of DDR can also be useful for the monotherapy or for combination with chemo and/or radiotherapy of cancer.

Hospitalization for adverse events under abiraterone or enzalutamide exposure in real-world setting: A French population-based study on prostate cancer patients

AIMS

Safety profiles of abiraterone and enzalutamide rely mainly on Phase III clinical trials. Our objective was to estimate the incidence rate ratio (IRR) for certain adverse events leading in real life to hospitalization (atrial fibrillation, acute heart failure, ischaemic heart disease, acute kidney injury [AKI], ischaemic stroke, torsade de pointe/QT interval prolongation, hepatitis and seizure), comparing abiraterone to enzalutamide. We also set out to discuss previously identified safety signals.

METHOD

Using the French National Health Insurance System database, all patients newly exposed to abiraterone or enzalutamide between 2013 and 2017 and followed until 31 December 2018 were targeted. IRRs for each event were estimated using a Poisson model in a sub-population of patients without contraindications or precautions for use for either treatment.

RESULTS

Among 11 534 new users of abiraterone and enzalutamide, AKI (IRR 1.42, 95% CI: 1.01-2.00), liver monitoring suggestive of hepatic damage (IRR 3.06, 95% CI: 2.66-3.53) and atrial fibrillation (IRR 1.12, 95% CI: 1.05-1.19) were significantly more often observed with abiraterone than with enzalutamide.

CONCLUSION

Our study provides knowledge on abiraterone and enzalutamide real-life safety profiles, especially for events leading to hospitalization. Despite several limitations, including the lack of clinical data, the safety signal for AKI under abiraterone is in line with results of an analysis of the French pharmacovigilance database, which requires further specific investigations. Enlightening the clinicians' therapeutic choices for patients treated for prostate cancer, our study should lead to clinicians being cautious in the use of abiraterone.

Deep and ongoing response of castrate-resistant prostate cancer on very low-dose enzalutamide in an elderly chemotherapy-naïve patient: a case report

Background

Enzalutamide is an orally administered drug that blocks signaling in the androgen receptor with clinical activity in both chemotherapy–naive and post-chemotherapy patients with castrate-resistant prostate cancer (CRPC). Enzalutamide is generally well-tolerated, but dose reductions are nonetheless needed in case of side effects.

Case

An 82-year-old patient with chemotherapy–naive metastatic castration-resistant prostate cancer was treated with a very low dose of 40 mg enzalutamide once daily. The trough levels of enzalutamide and the active metabolite N-desmethylenzalutamide were 4.5 mg/L and 3.0 mg/L, respectively. This exposure provided a long-term response without any significant side effects.

Conclusion

Low doses of enzalutamide may be efficacious, while also reducing the risk of side effects. Furthermore, employing a lower dose would reduce healthcare costs and increase access to enzalutamide. Studies exploring the efficacy of lower enzalutamide doses are warranted.

Medication patterns of abiraterone acetate plus prednisone or enzalutamide and PSA progression in veterans with metastatic castration-resistant prostate cancer

OBJECTIVES

To quantify the association between dose reductions of abiraterone acetate plus prednisone (AAP) or enzalutamide and prostate-specific antigen (PSA) progression in patients with metastatic castration-resistant prostate cancer (mCRPC). Changes in medication-taking patterns of AAP or enzalutamide may arise due to clinical (e.g. toxicity) and non-clinical (e.g. patient compliance) reasons in men with mCRPC. However, it is unclear how this affects PSA progression.

METHODS

Veterans Health Administration electronic health record database was used to identify Veterans diagnosed with prostate cancer who initiated AAP or enzalutamide (index) from April 2010 to December 2016. PSA progression was defined as the first rise in PSA of ≥2 ng/mL and ≥25% above nadir. The relative dose intensity (RDI) was defined as the ratio of the total dispensed dose over the last two months to the standard recommended dose and was updated monthly. Dose reduction was assessed using a threshold of RDI < 80%.

RESULTS

The cohort included 6069 Veterans aged 74.6 years on average. Mean follow-up was 12.3 months. PSA progression occurred in 62.7% of patients. About 63.6% of AAP- and 67.2% of enzalutamide-treated patients had ≥1 occurrence of RDI <80%. RDI <80% was associated with an 8.8% higher risk of PSA progression (hazard ratio [HR] = 1.088; p = .019; 95% confidence interval [CI] [1.014; 1.166]).

CONCLUSIONS

Dose reduction was observed in most patients and was associated with significantly higher risk of PSA progression in men with mCRPC. These results suggest future efforts to minimize dose reductions for non-clinical reasons are warranted and that patient adherence should be encouraged to limit the risk of PSA progression.

Development and clinical validation of a simple and fast UPLC-ESI-MS/MS method for simultaneous quantification of nine kinase inhibitors and two antiandrogen drugs in human plasma: Interest for their therapeutic drug monitoring

Kinase inhibitors (KIs) and antiandrogen drugs (AAs) are oral anticancer drugs with narrow therapeutic index that exhibit high inter- and intra-individual variability. We describe here a UPLC-MS/MS method for the simultaneous quantification of nine KIs: cobimetinib, dasatinib, ibrutinib, imatinib, nilotinib, palbociclib, ruxolitinib, sorafenib and vemurafenib; two active metabolites of them: N-desmethyl imatinib, N-oxide sorafenib; and two AAs: abiraterone and enzalutamide; with short pre-treatment and run time in order to be easily used in clinical practice for their therapeutic drug monitoring (TDM) and facilitating pharmacokinetics and pharmacokinetics/pharmacodynamics studies. Plasma samples were prepared by a single-step protein precipitation. Analytes were separated on a Waters Acquity UPLC® T3 HSS C18 column by non-linear gradient elution; with subsequent detection by Xevo® TQD triple quadrupole tandem mass spectrometer in a positive ionization mode. Analysis time was 2.8 min per run, and all analytes eluted within 1.46-1.97 minutes. The analytical performance of the method in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, dilution integrity and stability of analytes under different conditions met all criteria for a bioanalytical method for the quantification of drugs. The calibration curves were linear over the range of 1-500 ng/mL for abiraterone, dasatinib and ibrutinib; 5-500 ng/mL for cobimetinib and palbociclib; 10-5,000 ng/mL for imatinib, N-desmethyl imatinib, nilotinib, sorafenib, N-oxide sorafenib and ruxolitinib; 100-50,000 ng/mL for enzalutamide and 100-100,000 ng/mL for vemurafenib with coefficient of correlation above 0.995 for all analytes. This novel method was successfully applied to TDM in clinical practice.

[Adverse drug reactions profiles for abiraterone and enzalutamide: A pharmacovigilance descriptive analysis]

OBJECTIVE

The aim of this study was to describe the profile of adverse drug reactions (ADRs) observed with abiraterone and enzalutamide, based on cases registered in the French regional pharmacovigilance centres to identify potential pharmacovigilance signals.

METHODS

We extracted from the French pharmacovigilance database all cases of ADRs or drug interactions involving abiraterone or enzalutamide from the time they market authorization date until December 31st, 2017. Signal detection results have been transmitted by the French Agency for Health Products (ANSM). The data were compared with those of the risk management plans for each drug and the literature.

RESULTS

Among the 233 observations analyzed, nearly 62% involved abiraterone as a suspect drug and 38% involved enzalutamide; only 1 case involved both drugs. The ADRs profile is different between the drugs. Abiraterone is mostly associated with expected cardiac diseases (heart failure, and QT prolongation), expected with the drug. Also described, several cases of hepatotoxicity have been reported, however some cases with fatal outcome suggest that despite a follow-up of the liver function tests, it is difficult to anticipate this risk. Signals concerning acute renal failure and ischemic stroke have arisen. Enzalutamide is more particularly associated with various neurological disorders (convulsions, hallucinations, fatigue, and memory impairment) expected with the drug. While ischemic heart disease is also expected, signals of heart failure and atrial fibrillation have arisen. A potential hepatotoxicity of the molecule is discussed because of cases of cholestatic hepatitis.

CONCLUSION

The analysis of the French pharmacovigilance database cases allows to confirm an expected and monitored risk profile in the risk management plan for both drugs. Several signals have arisen, some of which will be investigated through a pharmacoepidemiology study.

Evaluation of dried blood spots as an alternative matrix for therapeutic drug monitoring of abiraterone and delta(4)-abiraterone in prostate cancer patients

Therapeutic drug monitoring (TDM) approaches may benefit patients treated with abiraterone acetate (AA) as drug efficacy is imprecise and important pharmacokinetic variability is known. Current methods based on the analysis of plasma present the disadvantage of the fast degradation of the analytes in the liquid sample. Dried blood spots (DBS) consist of a minimally invasive and unexplored sampling strategy to monitor the levels of abiraterone (ABI) and delta(4)-abiraterone (D4A) in patients. This study presents the development and validation of a precise and accurate method to monitor ABI and D4A in DBS samples by UPLC-MS/MS. Bioanalytical method validation was carried out according to current guidelines, evaluating the impact of DBS-specific parameters such as hematocrit and spot volume on accuracy. Based on the analysis of quality control samples prepared at low, medium and high concentrations, the method was precise with CV ≤ 6.97 % and 10.26 % for ABI and D4A, respectively. The method was also highly accurate, between 93.6-106.8 % for ABI and 96.0-108.5 % for D4A. The DBS method is compatible with the analysis of samples of unknown volume and hematocrit range of the studied population. In addition, ABI and D4A were stable for 7 days in DBS at room temperature, which is feasible for sample transportation in postal service and analysis in the laboratory. Method application to 16 clinical samples revealed good correlation between measured plasma concentrations and estimated plasma concentrations for ABI (r = 0.884, P < 0.05) and D4A (r = 0.920, P < 0.05). Passing-Bablok regression analysis and Bland-Altmann plots indicated correlation between the results obtained from DBS and plasma, with a slight overestimation of the concentrations of ABI in DBS, which could be related to the small study cohort. Therefore, the results of this first work indicate that DBS consist of a promising alternative sampling strategy in TDM studies of AA.

New 3β-hydroxysteroid-indolamine conjugates: Design, synthesis and inhibition of C6 glioma cell proliferation

Four novel indole steroids based on dehydroepiandrosterone (IS-1), estrone (IS-2) and pregnenolone (IS-3) were obtained and studied for their ability to inhibit C6 glioma proliferation. A reduction in cell proliferation by 52 ± 13% was observed for IS-1 at 10 μM, whereas IS-3 and abiraterone acetate at 10 μM caused a 36 ± 8% decrease. Surprisingly, the cellular effects reported for abiraterone, namely, cytochrome P450 CYP17A1 inhibition and endoplasmic reticulum stress were not detected for IS-1. However, both abiraterone and IS-1 significantly increased glutathione levels. Docking studies predicted good affinity of IS-1 to liver X receptors and regulatory protein Keap1, which are proposed to be involved in the compounds' antiproliferative activity.

Pharmacokinetic drug–drug interactions: an insight into recent US FDA-approved drugs for prostate cancer

Pharmacokinetic drug–drug interaction is a significant safety and efficiency concern as it results in considerable concentration changes. Drug–drug interactions are a substantial concern in anticancer drugs that possess a narrow therapeutic index. These interactions remain as the principal regulatory obstacle that can lead to termination in the preclinical stage, restrictions in the prescription, dosage adjustments or withdrawal of the drugs from the market. Drug metabolizing enzymes or transporters mediate the majority of clinically relevant drug interactions. Cancer diagnosed aged patients use multiple medications and are more prone to significant drug–drug interactions. This review provides detailed information on clinically relevant drug–drug interactions resulting from drug metabolism by enzymes and transporters with a particular emphasis on recent FDA approved antiprostate cancer drugs.

Androgen receptor inhibitor treatments: Cardiovascular adverse events and comorbidity considerations in patients with non-metastatic prostate cancer

OBJECTIVES

Prostate cancer and cardiovascular (CV) disease share several risk factors, with the incidence of both rising with increasing age. Systemic prostate cancer therapies may increase CV risk. For example, gonadotropic releasing hormone agonists have been associated with increased development of CV risk factors, and potentially with CV disease. For men with non-metastatic castration-resistant prostate cancer (nmCRPC), the opportunity to mitigate CV risk by appropriate selection of therapy (i.e., use of newer agents such as androgen receptor inhibitors) may be possible. The phase 3 PROSPER, SPARTAN, and ARAMIS trials for enzalutamide, apalutamide, and darolutamide, the 3 approved androgen receptor inhibitors for men with nmCRPC, were all associated with increased metastasis-free survival in patients with metastatic castration-resistant prostate cancer (mCRPC). Our objective in writing this review is to improve awareness of the relationship between long-term androgen deprivation and increased risk for CV disease and inform treatment decision making for patients with mCRPC who also have CV comorbidities.

METHODS

The PubMed database was searched from 2010 to November 5, 2019 for articles pertaining to androgen receptor inhibitors, androgen inhibition, apalutamide, darolutamide, enzalutamide, CV, and CaP.

RESULTS

We found literature describing the relationship between androgen inhibition and CV disease and risks. Given the increased risk of CV disease due to exposure to gonadotropic releasing hormone agonist therapy alone, understanding the potential for additional CV risks is important for patients with CV comorbidities when an androgen receptor inhibitor is added to their treatment. Another important consideration is the possibility of drug-drug interactions with comedications.

CONCLUSION

Management strategies for patients with mCRPC also treated for comorbidities including CV disease require appropriate selection of therapy, diet, and exercise to meet the needs of the individual patient profile.

CYP17A1 polymorphism c.-362T>C predicts clinical outcome in metastatic castration-resistance prostate cancer patients treated with abiraterone

BACKGROUND

Abiraterone became a standard hormonal therapy for patients with metastatic castration-resistance prostate cancer (mCRPC). However, patients may experience primary resistance to treatment. To date, few predictive biomarkers of efficacy have been identified. Our aim was to investigate the association between the single nucleotide polymorphism (SNP) c.-362T>C in the CYP17A1 gene, and clinical outcome in mCRPC patients treated with abiraterone.

PATIENTS AND METHODS

mCRPC patients candidate to receive abiraterone were enrolled in the present retrospective pharmacogenetic study. Based on a literature selection, CYP17A1 rs2486758 (c.-362T > C) was selected and analysed by real-time PCR on genomic DNA extracted from whole blood. Univariate analysis was performed to test the association between the SNP and treatment-related clinical outcomes.

RESULTS

Sixty mCRPC patients were enrolled in the present study. Patients carrying the mutant CYP17A1 c.-362CT/CC genotypes showed a shorter median progression-free survival (PFS) and prostate-specific antigen-PFS (PSA-PFS) compared to patients carrying the TT genotype (10.7 vs 14.2 months and 8 vs 16 months, respectively; p = 0.04). No association between the selected SNP and the overall survival was found.

CONCLUSIONS

These findings suggest an association between CYP17A1 c.-362T>C polymorphism and poorer clinical outcome with abiraterone for mCRPC patients. However, further validations on larger cohort of patients are needed to confirm its role as a predictive biomarker for abiraterone resistance.

Indications and Complications of Androgen Deprivation Therapy

OBJECTIVE

To review the indications for and side effects of androgen deprivation therapy (ADT) in men affected by prostate cancer.

DATA SOURCES

National guidelines, evidence-based summaries, peer-reviewed studies, and websites.

CONCLUSION

Indications for ADT include men with (1) intermediate- to high-risk localised prostate cancer undergoing radiation therapy, (2) biochemical recurrence after radical prostatectomy treated with salvage radiation therapy, or (3) metastatic prostate cancer. Several forms of ADT are available. To support self-management, body weight, diet, physical activity, alcohol consumption, and smoking should be discussed during clinical consultations. Important side effects of ADT may include flare-up phenomena of GnRH analogues, local reactions at injection sites, cardiovascular events, bone loss/fractures, drug-drug interactions, urinary tract dysfunction, hot flashes, cognitive impairment, seizure falls, and liver impairment.

IMPLICATIONS FOR NURSING PRACTICE

Nurses have a role in personalized cancer care and should be familiar with indications, side effects, and interventions to optimize quality of life for men affected by prostate cancer receiving ADT.

Pharmacokinetics, Safety, and Antitumor Effect of Apalutamide with Abiraterone Acetate plus Prednisone in Metastatic Castration-Resistant Prostate Cancer: Phase Ib Study

PURPOSE

Apalutamide is a next-generation androgen receptor (AR) inhibitor approved for patients with nonmetastatic castration-resistant prostate cancer (CRPC) and metastatic castration-sensitive prostate cancer. We evaluated the pharmacokinetics, safety, and antitumor activity of apalutamide combined with abiraterone acetate plus prednisone (AA-P) in patients with metastatic CRPC (mCRPC).

PATIENTS AND METHODS

Multicenter, open-label, phase Ib drug-drug interaction study conducted in 57 patients with mCRPC treated with 1,000 mg abiraterone acetate plus 10 mg prednisone daily beginning on cycle 1 day 1 (C1D1) and 240 mg apalutamide daily starting on C1D8 in 28-day cycles. Serial blood samples for pharmacokinetic analysis were collected on C1D7 and C2D8.

RESULTS

Systemic exposure to abiraterone, prednisone, and prednisolone decreased 14%, 61%, and 42%, respectively, when apalutamide was coadministered with AA-P. No increase in mineralocorticoid excess-related adverse events was observed. Patients without prior exposure to AR signaling inhibitors had longer median treatment duration and greater mean decrease in prostate-specific antigen (PSA) from baseline compared with those who had received prior therapy. Confirmed PSA reductions of ≥50% from baseline at any time were observed in 80% (12/15) of AR signaling inhibitor-naïve patients and 14% (6/42) of AR signaling inhibitor-treated patients.

CONCLUSIONS

Treatment with apalutamide plus AA-P was well tolerated and showed evidence of antitumor activity in patients with mCRPC, including those with disease progression on AR signaling inhibitors. No clinically significant pharmacokinetic interaction was observed between abiraterone and apalutamide; however, apalutamide decreased exposure to prednisone. These data support development of 1,000 mg abiraterone acetate plus 10 mg prednisone daily with 240 mg apalutamide daily in patients with mCRPC.

Considerations for interactions of drugs used for the treatment of COVID-19 with anti-cancer treatments

SARS-CoV2 infection is an emerging issue worldwide. Cancer patient are at increased risk of infection compared to general population. On the other hand, these patients are at major risk of drug interactions caused by renal and hepatic impairment background. Because of the long-term use of chemotherapy drugs, drug interactions are important in these patients especially with SARS-CoV2 treatments now. This paper is review of reported drug interactions of current treatments for COVID-19 and anticancer agents.

Renal and Cardiovascular Toxicities by New Systemic Treatments for Prostate Cancer

Prostate cancer (PC) is the most common male cancer in Western Countries. In recent years, the treatment of relapsed or metastatic disease had benefited by the introduction of a variety of new different drugs. In consideration of the relative long survival of PC patients, side effects of these drugs must be considered and monitored. In this review, we analyzed the newly developed therapies for PC treatment, describing the mechanism of action, the metabolism and latest clinical trials that led to the approval of these drugs in clinical practice. We then evaluated the cardiovascular and renal side effects from pivotal phase III and II studies and meta-analyses. Cardiovascular side effects are the most frequent, in particular hypertension, while renal toxicity is rarer and not well described in literature. Therefore, there is a need to better define the effects of these therapies, in order to personalize patient treatment on the basis of their comorbidities and preferences, in addition to their symptoms and disease load.

High Content Screening Using New U2OS Reporter Cell Models Identifies Harmol Hydrochloride as a Selective and Competitive Antagonist of the Androgen Receptor

Prostate cancer is the most commonly diagnosed malignancy in men. Its growth mainly relies on the activity of the androgen receptor (AR), justifying the use of androgen deprivation therapy as a gold standard treatment for the metastatic disease. Inhibition of the androgen axis using second generation antagonists has improved patients’ survival, but is systematically confronted to resistance mechanisms, leading to a median survival that does not exceed 5 years. Counteracting this resistance has been the object of a large number of investigations, with a particular emphasis towards the identification of new AR inhibitors, whether they antagonize the receptor by a competitive or a non-competitive binding. To this end, many high content screens have been performed, to identify new non-steroidal AR antagonists, using a variety of approaches, but reported somewhat controversial results, depending on the approach and on the cell model that was used for screening. In our study, we used the U2OS osteosarcoma cells stably transfected with AR or ARv7 and a luciferase reporter as a previously validated model to screen the Prestwick Phytochemical library. The results of our screen identified ellipticine, harmol, and harmine hydrochloride as confirmed hits. Surprisingly, we could demonstrate that harmol hydrochloride, previously identified as a non-competitive inhibitor of AR or a weak inhibitor of androgen signaling, was actually a competitive antagonist of AR, which inhibits the growth of VCaP prostate cancer line, at concentrations for which it did not affect the growth of the AR negative DU145 and PC3 cells. Interestingly, we also report for the first time that harmol hydrochloride was selective for AR, as it could not alter the activity of other nuclear receptors, such as the glucocorticoid receptor (GR), the progesterone receptor (PR), or the mineralocorticoid receptor (MR). Additionally, we demonstrate that, conversely to enzalutamide, harmol hydrochloride did not show any agonistic activity towards the pregnane X receptor (PXR), a master regulator of drug metabolism. Together, our results shed light on the importance of the cellular context for the screening of new AR antagonists. They further indicate that some of the potential hits that were previously identified may have been overlooked.

Efficacy of abiraterone combined with flutamide on prostate cancer patients and its effect on serum miR-493-5p and miR-195-5p

Efficacy of abiraterone combined with flutamide on patients with prostate cancer (PCa) and its effect on levels of miR-493-5p and miR-195-5p contained in serum were investigated. The medical records of 146 PCa patients admitted to Longhua Hospital Shanghai University of Traditional Chinese Medicine from January 2011 to December 2013 were selected. Eighty-four patients were treated with abiraterone combined with flutamide as a study group, 62 patients were treated with abiraterone alone as a control group. The curative effect, adverse reactions, quality of life and five-year overall survival (OS) of the two groups were compared. The serum prostate-specific antigen (PSA) level was measured by radioimmunoassay at 3 days (T1) before treatment, 1 month (T2), 2 months (T3), and 6 months (T4) after treatment, and the relative expression of miR-493-5p and miR-195-5p in serum were detected by qRT-PCR. The total effective rate of the study group was significantly higher than that of the control group (P<0.05). The total incidence of toxic and side effects in the study group was significantly lower than that in the control group (P<0.05). The improvement rate of quality of life in the study group was significantly higher than that in the control group (P<0.05). OS in the study group was significantly higher than that in the control group at 5 years (P<0.05). There was no significant difference in serum PSA level between the two groups at T1 (P>0.05); there was no significant difference in the relative expression of miR-493-5p and miR-195-5p between the two groups at T1 (P>0.05). In conclusion, abiraterone combined with flutamide has better curative effect and lower incidence of adverse reactions in patients with metastatic castration-resistant PCa (CRPC) than abiraterone alone, and can increase the expression levels of miR-493-5p and miR-195-5p in patient serum.