Adherence Measures for Patients with Metastatic Castration-Resistant Prostate Cancer Treated with Abiraterone Acetate plus Prednisone: Results of a Prospective, Cluster-Randomized Trial

Evaluation of adherence to abiraterone therapy in prostate cancer patients based on a population pharmacokinetic model

AIMS

Abiraterone treatment requires regular drug intake under fasting conditions due to pronounced food effect, which may impact patient adherence. The aim of this prospective study was to evaluate adherence to abiraterone treatment in patients with prostate cancer. To achieve this aim, an abiraterone population pharmacokinetic model was developed and patients' adherence has been estimated by comparison of measured levels of abiraterone with population model-based simulations.

METHODS

A total of 1469 abiraterone plasma levels from 83 healthy volunteers collected in a bioequivalence study were analysed using a nonlinear mixed-effects model. Monte Carlo simulation was used to describe the theoretical distribution of abiraterone pharmacokinetic profiles at a dose of 1000 mg once daily. Adherence of 36 prostate cancer patients treated with abiraterone was then evaluated by comparing the real abiraterone concentration measured in each patient during follow-up visit with the theoretical distribution of profiles based on simulations. Patients whose abiraterone levels were ˂5th or ˃95th percentile of the distribution of simulated profiles were considered to be non-adherent.

RESULTS

Based on this evaluation, 13 patients (36%) have been classified as non-adherent. We observed significant association (P = .0361) between richness of the breakfast and rate of non-adherence. Adherent patients reported significantly better overall condition in self-assessments (P = .0384). A trend towards a higher occurrence of adverse effects in non-adherent patients was observed.

CONCLUSIONS

We developed an abiraterone population pharmacokinetic model and proposed an advanced approach to medical adherence evaluation. Due to the need for administration under fasting conditions, abiraterone therapy is associated with a relatively high rate of non-adherence.

Prevalence and Causes of Discontinuation of Androgen Receptor Inhibitors in Advanced Prostate Cancer Patients and Analysis of Physician Management to Increase Duration of Therapy

OBJECTIVE

To investigate the prevalence and cause of early discontinuation (DC) of androgen receptor inhibitor (ARi) in advanced prostate cancer (PCa) patients. Additionally, to study the effect of changing ARi vs dose reduction on duration of treatment (DOT).

MATERIALS AND METHODS

A retrospective cohort study of 333 patients with advanced PCa who started ARi between 2016 and 2020 was performed. ARi medication, treatment duration, reason for DC, stage of PCa, prostate specific antigen, Gleason score, and prior PCa treatments were collected. The cohort was divided into 2 subgroups, patients that stayed on one medication (Group A) vs patients who changed ARi medication (Group B). Student's t test, chi-square test, and Kaplan-Meier survival analysis were performed.

RESULTS

At 1 year 28.8% of patient's had discontinued ARi. Reasons for DC were side effects (34.4%), death (34.4%), and cancer progression (18.8%). DOT was 13 months for enzalutamide, 13.7 months for abiraterone, 7.6 months for darolutamide, and 12.1 months for apalutamide. Average DOT for patients with a dose change was 13.4 months, similar to those without dose change at 13.9 months (P = .630). DOT was 12.7 months in Group A vs 19.8 months in Group B (P = .001).

CONCLUSION

In our study population DC of ARi is higher than reported in the published trials. Providing patients with an alternative ARi is associated with an increase in DOT while dose reduction is not. It is important for clinicians to understand the causes of early DC to develop strategies to maximize duration of therapy for management of advanced PCa patients.

Adherence to oral hormonal therapy in advanced prostate cancer: a scoping review

Background:

Orally administrated agents play a key role in the management of prostate cancer, providing a convenient and cost-effective treatment option for patients. However, they are also associated with adherence issues which can compromise therapeutic outcomes. This scoping review identifies and summarizes data on adherence to oral hormonal therapy in advanced prostate cancer and discusses associated factors and strategies for improving adherence.

Methods:

PubMed (inception to 27 January 2022) and conference databases (2020–2021) were searched to identify English language reports of real-world and clinical trial data on adherence to oral hormonal therapy in prostate cancer using the key search terms ‘prostate cancer’ AND ‘adherence’ AND ‘oral therapy’ OR respective aliases.

Results:

Most adherence outcome data were based on the use of androgen receptor pathway inhibitors in metastatic castration-resistant prostate cancer (mCRPC). Self-reported and observer-reported adherence data were used. The most common observer-reported measure, medication possession ratio, showed that the vast majority of patients were in possession of their medication, although proportion of days covered and persistence rates were considerably lower, raising the question whether patients were consistently receiving their treatment. Study follow-up for adherence was generally around 6 months up to 1 year. Studies also indicate that persistence may drop further with longer follow-up, especially in the non-mCRPC setting, which may be a concern when years of therapy are required.

Conclusions:

Oral hormonal therapy plays an important role in the treatment of advanced prostate cancer. Data on adherence to oral hormonal therapies in prostate cancer were generally of low quality, with high heterogeneity and inconsistent reporting across studies. Short study follow-up for adherence and focus on medication possession rates may further limit relevance of available data, especially in settings that require long-term treatment. Additional research is required to comprehensively assess adherence.

Breaking the Bottleneck in Anticancer Drug Development: Efficient Utilization of Synthetic Biology

Natural products have multifarious bioactivities against bacteria, fungi, viruses, cancers and other diseases due to their diverse structures. Nearly 65% of anticancer drugs are natural products or their derivatives. Thus, natural products play significant roles in clinical cancer therapy. With the development of biosynthetic technologies, an increasing number of natural products have been discovered and developed as candidates for clinical cancer therapy. Here, we aim to summarize the anticancer natural products approved from 1950 to 2021 and discuss their molecular mechanisms. We also describe the available synthetic biology tools and highlight their applications in the development of natural products.

Susceptibility to SARS-Cov-2 Infection and Risk for Severe COVID-19 in Patients with Prostate Cancer on Androgen Deprivation Therapy

Androgen deprivation therapy (ADT) has been hypothesized to protect against COVID‐19, but previous observational studies of men with prostate cancer on ADT have been inconsistent regarding mortality risk from coronavirus disease 2019 (COVID‐19). Using data from the Prostate Cancer data Base Sweden (PCBaSe), we identified a cohort of 114 547 men with prevalent prostate cancer on the start of follow‐up in February 2020, and followed them until 16 December 2020 to evaluate the association between ADT and time to test positive for COVID‐19. Among men testing positive for COVID‐19, we used regression analyses to estimate the association between ADT and risk of COVID‐19‐related hospital admission/death from any cause within 30 days of the positive test. In total, 1695 men with prostate cancer tested positive for COVID‐19. In crude analyses, exposure to ADT was associated with a 3‐fold increased risk of both testing positive for COVID‐19 infection and subsequent hospital admission/death. Adjustment for age, comorbidity and prostate cancer risk category substantially attenuated the associations: HR 1.3 (95% CI: 1.1‐1.5) for testing positive for COVID‐19, and OR 1.4 (95% CI: 1.0‐1.9) for risk of subsequent hospital admission/death. In conclusion, although these results suggest increased risks of a positive COVID‐19 test, and COVID‐19‐related hospital admission/death in men on ADT, these findings are likely explained by confounding by old age, cancer‐associated morbidity and other comorbidities being more prevalent in men on ADT, rather than a direct effect of the therapy.

ONS Guidelines™ to Support Patient Adherence to Oral Anticancer Medications

PURPOSE

This evidence-based guideline intends to support patients, clinicians, and others regarding interventions and processes to support patient adherence to oral anticancer medications (OAMs).

METHODOLOGIC APPROACH

A panel of healthcare professionals and patient representatives developed a clinical practice guideline to support patients taking OAMs. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology and criteria for trustworthy guidelines were followed. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool. A quantitative or narrative synthesis of the evidence was completed. Certainty of the evidence was assessed using GRADE.

FINDINGS

The panel agreed on recommendations and suggested an adherence risk assessment, education addressing adherence, ongoing assessment, proactive follow-up, coaching, and motivational interviewing in addition to usual care. The panel suggested the implementation of a structured OAM program.

IMPLICATIONS FOR NURSING

As cancer treatment shifts from clinic to home settings, interventions and programs to support patients on OAMs are needed.

Androgen deprivation therapy, comorbidity, cancer stage and mortality from COVID-19 in men with prostate cancer

BACKGROUND

Androgens facilitate entrance of the severe acute respiratory syndrome coronavirus 2 into respiratory epithelial cells, and male sex is associated with a higher risk of death from corona virus disease (COVID-19). Androgen deprivation therapy (ADT) could possibly improve COVID-19 outcomes.

METHODS

In a case-control study nested in the Prostate Cancer data Base Sweden (PCBaSe) RAPID 2019, we evaluated the association between ADT and COVID-19 as registered cause of death in men with prostate cancer. Each case was matched to 50 controls by region. We used conditional logistic regression to adjust for confounders and also evaluated potential impact of residual confounding.

RESULTS

We identified 474 men who died from COVID-19 in March-December 2020. In crude analyses, ADT exposure was associated with an increased risk of COVID-19 death (odds ratio [OR] 5.05, 95% CI: 4.18-6.10); however, the OR was substantially attenuated after adjustment for age, comorbidity, prostate cancer characteristics at diagnosis, recent healthcare use, and indicators of advanced cancer (adjusted OR 1.25, 95% CI: 0.95-1.65). If adjustment has accounted for at least 85% of confounding, then the true effect could be no more than a 5% reduction of the odds for COVID-19 death.

CONCLUSIONS

The increased mortality from COVID-19 in men with prostate cancer treated with ADT was mainly related to high age, comorbidity, and more advanced prostate cancer. There was no evidence to support the hypothesis that ADT is associated with improved COVID-19 outcomes.

Androgen deprivation therapy and excess mortality in men with prostate cancer during the initial phase of the COVID-19 pandemic

Background

Men have a higher risk of death from COVID-19 than women and androgens facilitate entrance of the SARS-CoV-2 virus into respiratory epithelial cells. Thus, androgen deprivation therapy may reduce infection rates and improve outcomes for COVID-19. In the spring of 2020, Sweden was highly affected by COVID-19. The aim was to estimate the impact of androgen deprivation therapy on mortality from COVID-19 in men with prevalent prostate cancer by comparing all-cause mortality in the spring of 2020 to that in previous years.

Patients and methods

Using the Prostate Cancer data Base Sweden all men with prostate cancer on March 1 each year in 2015–2020 were followed until June 30 the same year. Exposure to androgen deprivation therapy was ascertained from filled prescriptions for bicalutamide monotherapy, gonadotropin-releasing hormone agonists (GnRH), or bilateral orchidectomy.

Results

A total of 9,822 men died in March-June in the years 2015–2020, of whom 5,034 men were on androgen deprivation therapy. There was an excess mortality in 2020 vs previous years in all men. The crude relative mortality rate ratio for 2020 vs 2015–2019 was 0.93 (95% confidence interval (CI) 0.83 to 1.04) in men on GnRH, and 0.90 (95% CI 0.78 to 1.05) in men on bicalutamide monotherapy. After multivariable adjustment these ratios were attenuated to 1.00 (95% CI 0.89 to 1.12) and 0.97 (95% CI 0.84 to 1.12), respectively. When restricting the analysis to the regions with the highest incidence of COVID-19 or to the time period between 2 April to 10 June when mortality in 2020 was increased >30% compared to previous years, the results were similar to the main analysis.

Conclusions

In this large national population-based cohort of men with prevalent prostate cancer, there was no clear evidence in support for an effect of androgen deprivation therapy on COVID-19 mortality.