Drug-drug interaction potential among patients with nonmetastatic castration-resistant prostate cancer (nmCRPC) treated with novel androgen receptor inhibitors.

BACKGROUND: Nonmetastatic castration-resistant prostate cancer (nmCRPC) patients are often older and use concurrent medications that increase the potential for drug-drug interactions (pDDIs). This study assessed pDDI prevalence in real-world nmCRPC patients treated with apalutamide, darolutamide, or enzalutamide. RESEARCH DESIGN AND METHODS: Castrated prostate cancer patients without metastases prior to androgen receptor inhibitor initiation were identified retrospectively via Optum Clinformatics Data Mart claims data (8/2019-3/2021). The top 100 concomitant medications were assessed for pDDIs. RESULTS: Among 1,515 patients (mean age: 77 ± 8 years; mean Charlson Comorbidity Index: 3 ± 3), 340 initiated apalutamide, 112 darolutamide, and 1,063 enzalutamide. Common concomitant medication classes were cardiovascular (80%) and central nervous system (52%). Two-thirds of the patients received ≥5 concomitant medications; 30 (30/100 medications) pDDIs were identified for apalutamide and enzalutamide each and 2 (2/100 medications) for darolutamide. Most pDDIs had risk ratings of C or D, but four for apalutamide were rated X. Approximately 58% of the patients on apalutamide, 5% on darolutamide, and 54% on enzalutamide had ≥1 identified pDDI. CONCLUSIONS: Results showed a higher frequency of pDDIs in patients receiving apalutamide and enzalutamide vs darolutamide. The impact of these could not be determined retrospectively. DDI risk should be carefully evaluated when discussing optimal therapy for patients with nmCRPC.

Medication adherence among patients with advanced prostate cancer using oral therapies.

Aims: In light of the extended overall survival and improved quality of life provided by advanced prostate cancer (PC) oral therapies, this study aimed to describe treatment adherence to advanced PC oral therapies and evaluate associated patient characteristics and subsequent healthcare resource utilization (HRU). Patients & methods: Patients with advanced PC initiating apalutamide, enzalutamide or abiraterone acetate were identified from administrative data (October 1, 2014-September 30, 2019). Adherence and persistence at six months postinitiation were used to evaluate patient factors and HRU. Results: Aged ≥75 years, Black race, chemotherapy use and higher pharmacy paid amounts were associated with poor adherence/persistence, which translated to higher HRU. Conclusions: Strategies to increase adherence and persistence may improve patient outcomes and associated HRU.

Lay abstract This study included 27,262 patients with advanced prostate cancer who started taking one of three oral cancer medications (apalutamide, enzalutamide or abiraterone acetate) between October 2014 and September 2019. Patients who were black, aged 75 years or older, who had chemotherapy or who had higher prescription costs had the most difficulty following dosing guidelines or staying on treatment. Patients who did not follow dosing guidelines required more healthcare services. In light of the extended survival and improved quality of life that oral cancer medication for advanced prostate cancer provides, helping patients to take the correct medication dose, at the right time, and for the recommended length of time may improve their outcomes and reduce medical costs.

Apalutamide radio-sensitisation of prostate cancer.

INTRODUCTION: The combination of radiotherapy with bicalutamide is the standard treatment of prostate cancer patients with high-risk or locally advanced disease. Whether new-generation anti-androgens, like apalutamide, can improve the radio-curability of these patients is an emerging challenge. MATERIALS AND METHODS: We comparatively examined the radio-sensitising activity of apalutamide and bicalutamide in hormone-sensitive (22Rv1) and hormone-resistant (PC3, DU145) prostate cancer cell lines. Experiments with xenografts were performed for the 22Rv1 cell line. RESULTS: Radiation dose-response viability and clonogenic assays showed that apalutamide had a stronger radio-sensitising activity for all three cell lines. Confocal imaging for γΗ2Αx showed similar DNA double-strand break repair kinetics for apalutamide and bicalutamide. No difference was noted in the apoptotic pathway. A striking cell death pattern involving nuclear karyorrhexis and cell pyknosis in the G1/S phase was exclusively noted when radiation was combined with apalutamide. In vivo experiments in SCID and R2G2 mice showed significantly higher efficacy of radiotherapy (2 and 4 Gy) when combined with apalutamide, resulting in extensive xenograft necrosis. CONCLUSIONS: In vitro and in vivo experiments support the superiority of apalutamide over bicalutamide in combination with radiotherapy in prostate cancer. Clinical studies are encouraged to show whether replacement of bicalutamide with apalutamide may improve the curability rates.

Pharmacokinetics and Use-Testing of Apalutamide Prepared in Aqueous Food Vehicles for Alternative Administration.

Patients may have difficulty swallowing a whole daily dose of 240 mg (4 × 60-mg tablets) of apalutamide. One of the unique properties of apalutamide tablets is easy disintegration and dispersion when mixed into aqueous vehicles, avoiding the need to crush/split the tablets. To evaluate whether this method of apalutamide tablet administration would be conducive in a patient setting, different variations in preparation were evaluated, and one preparation was tested in humans. In vitro compatibility studies evaluated purity, dose, or stability of different variations of apalutamide in applesauce/yogurt/orange juice/green tea. An open-label, randomized, crossover phase 1 study in healthy men determined the bioavailability of an apalutamide-applesauce mixture versus whole tablets based on maximum plasma analyte concentration (Cmax ), area under the plasma analyte concentration-time curve: AUC0-72h and AUC0-168h . Different amounts of applesauce/yogurt/orange juice/green tea as well as durations (up to 6 hours) did not affect the total apalutamide content available. The phase 1 study (n = 12) showed increased total exposure of 5% and peak exposure of 27.6% when comparing the apalutamide-applesauce mixture with whole-tablet administration. Variations in preparation times and total content for applesauce/yogurt/orange juice/green tea did not affect the purity, dose, or stability of apalutamide. An apalutamide-applesauce mixture is a suitable alternative administration method to whole tablets.

Apalutamide plus Androgen Deprivation Therapy for Metastatic Castration-Sensitive Prostate Cancer: Analysis of Pain and Fatigue in the Phase 3 TITAN Study.

PURPOSE: We performed an exploratory analysis of prostate cancer-related pain and fatigue on health-related quality of life in patients with metastatic castration-sensitive prostate cancer receiving apalutamide (240 mg/day) or placebo, with continuous androgen deprivation therapy (ADT), in the phase 3, randomized, double-blind, placebo controlled TITAN trial (NCT02489318). MATERIALS AND METHODS: Patient-reported outcomes for pain and fatigue were evaluated using the Brief Pain Inventory-Short Form and Brief Fatigue Inventory. Time to deterioration (TTD) was estimated by Kaplan-Meier method; hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards model. General estimating equations for logistic regression estimated treatment-related differences in the likelihood of worsening pain or fatigue. RESULTS: Compliance for completing the Brief Pain Inventory-Short Form and Brief Fatigue Inventory was high (96% to 97%) in the first year. Median followup times were similar between treatments (19 to 22 months). Median pain TTD was longer with apalutamide than placebo for "pain at its least in the last 24 hours" (28.7 vs 21.8 months, respectively; p=0.0146), "pain interfered with mood" (not estimable vs 22.4 months; p=0.0017), "pain interfered with walking ability" (28.7 vs 20.2 months; p=0.0027), "pain interfered with relations" (not estimable vs 23.0 months; p=0.0139) and "pain interfered with sleep" (28.7 vs 20.9 months; p=0.0167). Likelihood for fatigue and worsening fatigue were similar between groups. CONCLUSIONS: Patients with metastatic castration-sensitive prostate cancer receiving apalutamide plus ADT vs placebo plus ADT reported consistently favorable TTD of pain. No difference for change in fatigue was observed with apalutamide vs placebo.

Indirect Comparison of Darolutamide versus Apalutamide and Enzalutamide for Nonmetastatic Castration-Resistant Prostate Cancer.

PURPOSE: No published head-to-head randomized trials have compared the safety and efficacy of darolutamide vs apalutamide or enzalutamide in nonmetastatic castration-resistant prostate cancer. This study compares prespecified adverse events and metastasis-free survival associated with darolutamide vs apalutamide, and darolutamide vs enzalutamide, via matching-adjusted indirect comparisons. MATERIALS AND METHODS: Individual patient data from the phase III ARAMIS trial (NPLACEBO=553; NDAROLUTAMIDE=943) were selected and reweighted to match the inclusion criteria and baseline characteristics published for the phase III SPARTAN (NPLACEBO=401; NAPALUTAMIDE=806) and PROSPER (NPLACEBO=468; NENZALUTAMIDE=933) trials. Only baseline factors consistently reported across trials were included as matching covariates. Both indirect comparisons matched on age, prostate specific antigen level and doubling time, Eastern Cooperative Oncology Group performance status, Gleason score, and bone-sparing agent use. Darolutamide vs apalutamide also matched on prior surgery and darolutamide vs enzalutamide also matched on region. Risk differences and odds ratios were calculated for adverse events and hazard ratios for metastasis-free survival. RESULTS: No differences in metastasis-free survival hazard ratios were found after matching in either comparison. However, fall, fracture and rash rates were statistically significantly lower in favor of darolutamide vs apalutamide. Fall, dizziness, mental impairment, fatigue and severe fatigue rates were statistically significantly lower in favor of darolutamide vs enzalutamide. CONCLUSIONS: While metastasis-free survival did not differ across drugs in these cross-trial indirect comparisons, darolutamide showed a favorable safety and tolerability profile in prespecified adverse events vs apalutamide and enzalutamide. Consideration of these adverse events is important in clinical decision-making and treatment selection in nonmetastatic castration-resistant prostate cancer.

Darolutamide in hormone-sensitive and castration-resistant prostate cancer.

Introduction: Important changes in the treatment of prostate cancer have taken place in recent years. Non-metastatic castration-resistant prostate cancer (nmCRPC) has been clinically delineated. In this setting, three drugs have been approved in high-risk disease: apalutamide, enzalutamide and darolutamide.Areas covered:This manuscript aims to profile darolutamide, its clinical development, pharmacologic properties, efficacy and safety. We presented the results of published clinical studies, but we also investigated ongoing ones.Expert opinion: An indirect comparison with the other two aforementioned drugs emerged. While the clinical efficacy is comparable, the toxicity profile is different for darolutamide, resulting in greater tolerance. We must wait for the results of the trials that study darolutamide in hormone-sensitive disease, both in the metastatic phase and in the localized phase. Clinical experience will also be important to determine ever more personalized treatments for patients.

Potential risk for developing severe COVID-19 disease among anabolic steroid users.

A severe case of COVID-19 was observed in an otherwise healthy 28-year-old man who had taken oxandrolone 40 mg/day as an anabolic steroid. The patient had been taking oxandrolone for enhanced bodybuilding 30 days prior to presenting to an outpatient clinic with COVID-19 symptoms. The patient reported that his symptoms have rapidly worsened over the course of 4 days prior to presenting at the clinic. As part of an experimental antiandrogen treatment for hyperandrogenic men suffering from COVID-19, he was administered a single 600 mg dose of the novel antiandrogen proxalutamide. Twenty-four hours after administration of this dose, marked improvement of symptoms and markers of disease severity were observed. To our knowledge, this is the first case that potentially links anabolic steroid use to COVID-19 disease severity.

Apalutamide, darolutamide and enzalutamide in nonmetastatic castration-resistant prostate cancer: a meta-analysis.

Aim: Comparison of the efficacy/safety/health-related quality of life of apalutamide, enzalutamide and darolutamide in Phase III clinical trials involving patients with nonmetastatic castration-resistant prostate cancer was performed. Materials & methods: Relevant studies were identified by searching PubMed as well as conference abstracts reporting updated overall survival. Three pivotal trials were identified, SPARTAN (apalutamide), PROSPER (enzalutamide) and ARAMIS (darolutamide), and form the basis of this analysis. Results: All three drugs significantly prolonged metastasis-free survival, prostate-specific antigen response and overall survival versus placebo, and were generally well tolerated. Conclusion: Drug selection will likely be influenced by tolerability/safety and other factors, such as the propensity for drug-drug interactions and the presence of comorbidities, that affect the risk-benefit balance in individual patients.

The development of apalutamide for the treatment of prostate cancer.

INTRODUCTION: Prostate cancer progresses, despite androgen-deprivation therapy, the backbone of its treatment. This progression is mainly related to the androgen receptor (AR)-related mechanisms of resistance, and, several AR-targeted therapies have demonstrated benefit in metastatic and nonmetastatic disease. Apalutamide is a third-generation AR-targeted therapy which competitively blocks the AR and prevents AR dimerization, nuclear internalization, thereby avoiding cancer progression. Early studies have demonstrated that apalutamide was safe and demonstrated clinical benefit. Phase II and phase III studies had confirmed preliminary results of clinical benefit with apalutamide in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC) and in metastatic hormone-sensitive prostate cancer (mHSPC). AREAS COVERED: Herein, the authors discuss the development of apalutamide, from its discovery and early studies to phase III trials. They also examine new perspectives and biomarkers that may help oncologists to make decisions in patients taking apalutamide. Studies evaluating apalutamide in other settings and in combination with other therapies are also debated. EXPERT OPINION: Apalutamide has become a relevant therapy for patients with nmCRPC and mHSPC for its benefit in delaying metastasis in addition to its improvement of overall survival, without compromising the quality of life. Apalutamide should be considered as a standard-of-care for patients with nmCRPC and patients with mHSPC.

Quantitative determination of proxalutamide in rat plasma and tissues using liquid chromatography/tandem mass spectrometry.

RATIONALE: Proxalutamide is a novel drug for the treatment of prostate cancer. However, to date, there are almost no reports on the pharmacokinetics of proxalutamide in vivo. This study developed a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to determine the concentrations of proxalutamide in biological samples for pharmacokinetic studies. METHODS: Chromatographic separation was achieved on a Kromasil 100-5C8 column followed by gradient elution using a Shimadzu HPLC system. MS was performed in positive ion electrospray ionization mode using a SCIEX API 4000 triple quadrupole system. A simple and rapid one-step protein precipitation method was used for sample processing, and a low sample volume of 10 µL was used for processing and analysis. RESULTS: The method was validated to show good selectivity, sensitivity, precision, and accuracy. Good linearity (r2 > 0.99) was observed for rat plasma (range: 2-5000 ng/mL) and rat tissue homogenates (range: 2-2000 ng/mL). The extraction recovery was above 98%, and no significant matrix effect was observed. This method was successfully applied to investigate the pharmacokinetics and tissue distribution of proxalutamide in rats. CONCLUSIONS: A rapid and sensitive LC/MS/MS method was developed and validated to determine the quantity of proxalutamide in rat plasma and tissue homogenates and to further study the pharmacokinetic parameters of proxalutamide in a rat model. The results showed that proxalutamide had good oral bioavailability and wide tissue distribution in vivo.

Apalutamide: A Review in Metastatic Castration-Sensitive Prostate Cancer.

Apalutamide (Erleada®) is an oral selective androgen receptor (AR) inhibitor that binds directly to the ligand-binding domain of the AR. It is approved in the EU and the USA for the treatment of adult men with metastatic castration-sensitive prostate cancer (mCSPC). In a multinational, phase III study (TITAN) in this patient population, the addition of apalutamide (240 mg once daily) to androgen deprivation therapy (ADT) significantly improved median radiographic progression-free survival (rPFS), median overall survival (OS) and the median time to cytotoxic chemotherapy, while maintaining health-related quality of life (HR-QOL) and not substantially differing from placebo plus ADT in safety. Although mature OS data are awaited with interest, the addition of apalutamide to ADT extends the treatment options available for standard of care in adult men with mCSPC.

Recent developments in the treatment of non-metastatic castration resistant prostate cancer.

Non-metastatic castration resistant prostate cancer (nmCRPC) is defined as a disease state withlack of radiographic evidence of metastatic disease, a confirmed rising PSA level on continuous ADT and maintaining a castrate level of testosterone following definitive therapy. Prior to the publication of PROSPER, SPARTAN and ARAMIS, no trials have demonstrated a clinical benefit for these patients. Recently enzalutamide, apalutamide, and darolutamide respectively, were tested in this disease setting with metastasis free survival (MFS) as the primary endpoint for each trial. In this review article, we define key terms related to the discussion of nmCRPC, examine the clinical trial design, and safety profile for each of these three key clinical trials and present updated overall survival (OS) results from these studies. Also we specifically discuss the key clinical trial results including the primary endpoint of MFS for each trial as well as quality of life effects of these three androgen receptor antagonists. Finally, this article examines the potential impact of molecular imaging testing on the applicability of these clinical trial results.

Efficacy and Safety Exposure-Response Relationships of Apalutamide in Patients with Nonmetastatic Castration-Resistant Prostate Cancer.

PURPOSE: To evaluate the relationship between exposure of apalutamide and its active metabolite, N-desmethyl-apalutamide, and selected clinical efficacy and safety parameters in men with high-risk nonmetastatic castration-resistant prostate cancer. PATIENTS AND METHODS: An exploratory exposure-response analysis was undertaken using data from the 1,207 patients (806 apalutamide and 401 placebo) enrolled in the SPARTAN study, including those who had undergone dose reductions and dose interruptions. Univariate and multivariate Cox regression models evaluated the relationships between apalutamide and N-desmethyl-apalutamide exposure, expressed as area under the concentration-time curve at steady state, and metastasis-free survival (MFS). Univariate and multivariate logistic regression models assessed the relationship between apalutamide and N-desmethyl-apalutamide exposure and common treatment-emergent adverse events including fatigue, fall, skin rash, weight loss, and arthralgia. RESULTS: A total of 21% of patients in the apalutamide arm experienced dose reductions diminishing the average daily dose to 209 mg instead of 240 mg. Within the relatively narrow exposure range, no statistically significant relationship was found between MFS and apalutamide and N-desmethyl-apalutamide exposure. Within apalutamide-treated subjects, skin rash and weight loss had a statistically significant association with higher apalutamide exposure. CONCLUSIONS: The use of apalutamide at the recommended dose of 240 mg once daily provided a similar delay in metastases across the SPARTAN patient population, regardless of exposure. The exploratory exposure-safety analysis supports dose reductions in patients experiencing adverse events.

Apalutamide in combination with autophagy inhibitors improves treatment effects in prostate cancer cells.

BACKGROUND: ARN-509 (Apalutamide) is a unique androgen receptor (AR) antagonist for the treatment of castration-resistant (CR) prostate cancer (PC). It inhibits AR nuclear translocation, DNA binding and transcription of AR gene targets. As dysregulation of autophagy has been detected in PC, the targeting of autophagy is a potential approach to overcome early therapeutic resistance. Therefore, we investigated the characteristics of autophagic response to ARN-509 treatment and evaluated the potential effect of a combination with autophagy inhibition. METHODS: Human prostate cancer cells (LNCaP) were cultivated in a steroid-free medium. Cells were treated with ARN-509 (50 µM) alone or in combination with the autophagy inhibitors 3-methyladenine (3MA, 5 mM) or chloroquine (Chl, 20 µM) or with ATG5 siRNA knock-down. Cell viability and apoptosis were measured by flow cytometry and fluorescence microscopy. Autophagy was monitored by immunohistochemistry, AUTOdot and immunoblotting (WES). RESULTS: Treatment with ARN-509 led to cell death of up to 37% with 50 µM and 60% with 100 µM by day 7. The combination of 50 µM ARN-509 with autophagy inhibitors produced a further increase in cell death by day 7. Immunostaining results showed that ARN-509 induced autophagy in LNCaP cells as evidenced by elevated levels of ATG5, Beclin 1 and LC3 punctuation and by an increase in the LC3-II band detected by WES. Autophagic flux was restored by the treatment of cells with Chl, intensifying the LC3-II band. These findings were further supported by an enhanced autophagosome punctuation observed by Autodot staining. CONCLUSIONS: These data demonstrate that treatment with ARN-509 leads to increased autophagy levels in LNCaP cells. Furthermore, in combination with autophagy inhibitors, ARN-509 provided a significantly elevated antitumor effect, thus providing a new therapeutic approach potentially translatable to patients.

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.

Prostate-specific antigen dynamics predict individual responses to intermittent androgen deprivation.

Intermittent androgen deprivation therapy (IADT) is an attractive treatment for biochemically recurrent prostate cancer (PCa), whereby cycling treatment on and off can reduce cumulative dose and limit toxicities. We simulate prostate-specific antigen (PSA) dynamics, with enrichment of PCa stem-like cell (PCaSC) during treatment as a plausible mechanism of resistance evolution. Simulated PCaSC proliferation patterns correlate with longitudinal serum PSA measurements in 70 PCa patients. Learning dynamics from each treatment cycle in a leave-one-out study, model simulations predict patient-specific evolution of resistance with an overall accuracy of 89% (sensitivity = 73%, specificity = 91%). Previous studies have shown a benefit of concurrent therapies with ADT in both low- and high-volume metastatic hormone-sensitive PCa. Model simulations based on response dynamics from the first IADT cycle identify patients who would benefit from concurrent docetaxel, demonstrating the feasibility and potential value of adaptive clinical trials guided by patient-specific mathematical models of intratumoral evolutionary dynamics.

An FDA Review of Drug Development in Nonmetastatic Castration-resistant Prostate Cancer.

The FDA has approved three androgen receptor inhibitors-enzalutamide, apalutamide, and darolutamide-for the treatment of patients with nonmetastatic castration-resistant prostate cancer (nmCRPC). These approvals were all based on randomized, double blind, placebo-controlled trials demonstrating large improvements in metastasis-free survival (MFS) and internally consistent evidence of benefit seen across secondary endpoints. In this article, we summarize the FDA regulatory history of MFS and we describe the design, conduct, and results of the three pivotal trials supporting these important treatment options for patients with nmCRPC.

Factors to Guide Treatment Selection for Hormone-Sensitive Metastatic Prostate Cancer.

For decades, the mainstay of treatment for metastatic hormone-sensitive prostate cancer has been androgen deprivation therapy. In recent years, 4 systemic therapies-docetaxel, abiraterone, enzalutamide, and apalutamide-have improved overall survival for men with metastatic hormone-sensitive prostate cancer when combined with androgen deprivation therapy, raising the question of which treatment to choose. The role for metastasis-directed therapy with surgery or radiation among these new treatments has also yet to be defined. Thus, several factors have come into play to guide treatment selection, including disease characteristics, age, fitness, and comorbidities of the patient, potential adverse effects of therapies, and health system considerations such as access to care and financial toxicity. Careful and shared decision making between patient and provider is critical. Future directions aimed at refining our treatment selection include researching the role of novel molecular imaging techniques, biomarkers predicting therapy response, sequencing and combining therapies, and understanding the long-term and late effects of these treatments.