Clinicians’ Perspectives on the Impact of Different Attributes of Androgen Receptor Pathway Inhibitors on Prostate Cancer Treatment Preferences and Compliance in Mexico

Abstract

Introduction

Androgen receptor pathway inhibitors (ARPIs) are a critical prostate cancer (PC) treatment option. Previous research has suggested that the physical attributes of ARPI medications (e.g., pill formulation, pill shape, pill size, dosing) may influence patients’ treatment satisfaction, adherence, and persistence, which may impact patient outcomes and quality of life. The objective of this study was to describe Mexican clinical experts’ perspectives on how different attributes of pill forms of ARPIs may affect treatment preferences and compliance in patients with PC.

Methods

This study employed a mixed-methods sequential design. In the first phase, we conducted a targeted literature review (TLR) to frame discussions with clinical experts. In phase 2, we conducted a structured expert elicitation (SEE) comprised of a survey, semi-structured individual interviews, and two focus groups with oncologists and urologists to gather insights about the influence of different ARPI attributes on patient preferences and compliance. In the third phase, we constructed a series of probabilistic mathematical models to analyze the likelihood of patients’ treatment preferences and adherence.

Results

The TLR identified pill size, shape, number, frequency, and form as key attributes that influence patients’ experiences and treatment compliance. Simpler regimens and smaller, easier-to-swallow formulations were consistently linked to greater comfort and adherence. In the SEE, participants ranked dosing frequency and pill count as the factors with the greatest influence on patient adherence when efficacy was comparable. During the interviews and focus groups, participants highlighted the importance of ≤ 2 pills/day, once-daily dosing, and small pill size alternatives. Findings from the Monte Carlo models were consistent with the earlier phases, supporting the importance of patient-preferred formulations.

Conclusions

Findings from this mixed-methods study indicate that patient-preferred formulations may support better treatment adherence and support consideration of patient preferences in treatment decision-making between clinicians and patients to optimize adherence and outcomes in PC management.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1007/s40487-026-00457-4.

Key Summary Points

Why carry out this study?

Previous research suggests that the physical attributes of androgen receptor pathway inhibitors (ARPIs) may influence treatment adherence and patient experience.

This study sought to describe Mexican clinical experts’ perspectives on how different attributes of pill forms of ARPIs may affect treatment preferences and compliance in patients with prostate cancer (PC).

What was learned from this study?

Participants ranked pill count, dosing frequency, and pill size as the factors with the greatest influence on patient adherence when efficacy was comparable, with consensus indicating that a single dosing intake scheme was preferred. Participants across oncology and urology specialties noted that pill characteristics can pose meaningful barriers to treatment adherence for older adults and high‑risk patients with PC, especially those with dysphagia, cognitive impairment, or polypharmacy.

Our findings consistently suggested that regimens with fewer total pills, fewer daily doses, and smaller pill size were perceived by clinical experts as more favorable for patient preference and adherence.

These results support considering patient preferences during shared treatment decision-making, particularly when treatments have comparable efficacy.

Introduction

Prostate cancer (PC) is the abnormal and uncontrolled division of cells present in the prostate gland and is typically slow growing [1, 2]. Globally, PC is the second-most common cancer in men and fourth most common cancer overall [3, 4]. Risk factors associated with PC include older age, race/ethnicity, geography, family history, and genetic factors [5].

In Mexico, PC is the top ranked cause of death among malign neoplasms in males [6]. As of 2022, the mortality rate of PC in Mexico was 63.8 deaths per 100,000 men aged 55 years and older, which is higher than the age-standardized rate for males age 55 years and older in North America (54.1 deaths per 100,000) [7]. Systemic treatment options for metastatic PC in Mexico include salvage therapy, androgen deprivation therapy, and androgen receptor pathway inhibitors (ARPIs; abiraterone, apalutamide, darolutamide, enzalutamide) [8–10]. Reviews and cohort analyses in hematologic and solid tumors suggest nonadherence may reduce treatment response and potentially increase progression or relapse risk [11]. Adherence-related issues are particularly relevant in metastatic PC because treatment is often prolonged and dependent on oral, self-administered therapies such as ARPIs. Many patients are older and may have comorbidities, polypharmacy, or swallowing difficulties, creating practical barriers to consistent treatment use.

Previous research suggests that factors such as pill formulation and treatment characteristics (e.g., treatment regimen and pill form) can significantly impact patient experiences and treatment compliance [12]. Treatment compliance, the extent to which a patient follows the prescribed dosing regimen, encompasses both adherence (i.e., likelihood that patients will use the treatment as prescribed) and persistence (i.e., likelihood that patients will continue treatment over time) [13]. By influencing treatment compliance, treatment characteristics may also indirectly affect treatment effectiveness and tolerability in real-world clinical practice, as well as patients’ satisfaction and health-related quality of life [12, 14, 15]. However, although prior studies suggest that pill characteristics may influence patient experience and adherence, evidence remains limited regarding how clinicians who routinely manage patients with PC perceive these attributes, particularly in Mexico. Because treatment decisions are often made jointly by clinicians and patients, understanding clinician perspectives may help identify practical barriers to adherence that are not well captured in the current literature.

In terms of specific treatment characteristics, previous research suggests that patients often prefer tablets over capsules, as well as smaller medications. Capsules typically consist of gelatin shells filled with liquid or powder medication, while tablets are compressed solid forms that may be coated to aid swallowing.[16]. These differences can influence patient perceptions, ease of use, and tolerability. Supporting these findings, a survey-based study of 25 patients with castration-resistant PC reported that 84% of these patients would prefer tablets over capsules, and more than 80% believed that adherence would likely be better with tablets [15]. Previous clinical observations also demonstrate that smaller pill sizes are preferred, and increasingly larger sizes may result in swallowing problems [17].

Although previous studies suggest that patients may prefer simpler regimens and smaller, easier-to-swallow pill formulations, limited evidence is available on how clinicians perceive the relevance of these attributes to patient preference, adherence, and persistence in routine PC care. Understanding these perceptions may help healthcare providers anticipate patient needs and adherence barriers, which may inform treatment decision-making between patients and providers.

The primary objective of this study was to describe Mexican clinical experts’ perspectives on how different attributes of pill forms of ARPI alternatives (i.e., form, shape, size, and dosing frequency) could impact treatment preferences and compliance in patients with PC.

Our secondary objectives were to: (1) describe clinical experts’ perspectives on how these different attributes may impact treatment persistence; (2) describe clinical experts’ perspectives on how patients’ treatment preferences and compliance could impact clinical outcomes; and (3) generate a decision analytic model to analyze and simulate the likelihood of treatment preferences and treatment adherence and persistence being impacted by these treatment attributes.

Methods

Study Design

This mixed-methods sequential study consisted of three phases (Fig. 1): (1) a targeted literature review (TLR); (2) a structured expert elicitation (SEE) process; and (3) a mathematical construction of a probabilistic model. Each of these phases informed the subsequent phase.

Fig. 1.

Study design diagram. ARPIs androgen receptor pathway inhibitors, mCRPC metastatic castration-resistant prostate cancer, nmCRPC nonmetastatic castration-resistant prostate cancer, SEE structured expert elicitation, TLR targeted literature review

Phase 1: Targeted Literature Review

The TLR was conducted to inform the survey design and frame the discussions with clinical experts in phase 2. Details of how the TLR was conducted, along with the search strategy, are provided in Supplementary Table 1 and the Supplementary Methods.

Phase 2: Structured Expert Elicitation

The SEE method is a scientific technique designed to organize and facilitate structured group communication, with the objective of eliciting insights on current or future challenges, particularly in scenarios where information is limited [18]. The method seeks to provide insights about the extent of uncertainty, sources of uncertainty, the extent of agreement/disagreement, and reasons for any disagreement among experts consulted.

Eligible participants were board-certified physicians currently practicing in the Mexican public healthcare system as an oncologist or urologist and had experience treating metastatic and/or nonmetastatic castration-resistant PC (mCRPC, nmCRPC) for ≥ 4 years and/or had prescribed ARPIs to ≥ 150 patients. Clinical experts were excluded from the study if they were unwilling or unable to sign confidentiality agreements and/or provide informed consent. Ultimately, eight oncologists and eight urologists participated in the study. Participant characteristics collected were age, city of residence, years of practice, and practice type. Demographic information on the sex and race/ethnicity of participants was not collected as it was not considered relevant to the study objectives. There are no formal power calculations to determine the sample size required for the SEE and sufficient sample sizes can range from 3 to 16 experts [19]. Further details regarding participant selection are provided in the Supplementary Methods.

The study was designed and executed by IQVIA, an independent contract research organization, on behalf of the sponsor. Industry-affiliated authors and sponsor representatives were not present during interviews or focus groups, which were led by independent IQVIA researchers to minimize social desirability and sponsor-related bias. To further mitigate bias, the study used a structured, prespecified mixed-methods design incorporating a TLR, standardized surveys, semi-structured interviews, and predefined consensus thresholds. Participants were blinded to the specific medications under evaluation and assessed treatment profiles on the basis of prespecified formulation attributes rather than branded products. Data were summarized as aggregated clinician responses across participants and study phases.

In the first stage of the SEE, participants completed a survey that evaluated their perceptions regarding trade-offs between four different ARPI options and the estimated proportions of patients who they believed would prefer some treatment attributes over others, possible reasons for these preferences, and the percentage of patients who may have challenges with treatment compliance. Informed by the TLR and study objectives, the survey instrument used attributes and levels refined for respondent comprehension. It included standardized descriptions, hypothetical profiles, and comprehension questions; interviews explored question clarity, interpretation, and elicited ranges. Details of the survey are provided in the Supplementary Methods.

As part of the survey, participants were asked to consider the influence of five medication characteristics on patients’ preferences: pill form (tablet or capsule), shape (elongated or round), size (21 mm × 10 mm, 10 mm × 10 mm, 17 mm × 9 mm, 16 mm × 8 mm) [15], total number of pills per day (2 or 4), and dosing frequency per day (once or twice daily) (Table 1).

Table 1.

Medication types

Characteristics	Medication 1	Medication 2	Medication 3	Medication 4
Pill Form Type	Soft gel capsule	Tablet	Tablet	Tablet
Form	Elongated	Round	Elongated	Elongated
Size	21 mm x 10 mm	10 mm x 10 mm	17 mm x 9 mm	16 mm x 8 mm
Total Number per Day	4 capsules administered in a single intake	4 tablets administered in a single intake	2 tablets administered in a single intake	2 tablets administered in 2 intakes (total 4 tablets per day)

Participants were also asked to evaluate four specific medication examples (Table 1). Medication 1 was formulated as a soft gel capsule with an elongated shape (21 mm × 10 mm) and a recommended dosage of four capsules taken once daily. Medication 2 was formulated as a round tablet (10 mm × 10 mm) with a recommended dosage of four tablets taken once daily. Medication 3 was formulated as an elongated tablet (17 mm × 9 mm) with a recommended dosage of two tablets taken once daily. Medication 4 was formulated as an elongated tablet (16 mm × 8 mm) with a recommended dosage of two tablets per intake, taken twice daily (total: 4 tablets/day).

Participants were asked to rank various attributes (form, shape, size, and dosing) of pill forms of ARPIs in the survey based on the perceived importance they believed each attribute had in impacting treatment preferences, adherence, and persistence. For the purposes of this study, preference was defined as patients’ choices about healthcare and medical treatment, based on personal beliefs and experiences, and trade-offs between positive and negative aspects of treatment [20]. Adherence was defined as patients’ degree of conformity to use the treatment as prescribed, and persistence referred to the likelihood that patients would continue the treatment over time [21].

Descriptive analyses were performed to describe the study sample and survey response patterns. Continuous data were summarized as the number of observations, central tendency, standard deviation, interquartile range, and range. Categorical data were described by the number and percentage of participants in each category. Missing and invalid observations were tabulated as separate categories.

After reviewing the aggregated survey data, participants revisited and adjusted their estimates to determine a clearer and more consistent prioritization of pill characteristics that would most realistically align with everyday patient needs and adherence challenges. A swing-weighting approach [22] was also used to evaluate which attribute, among a provided list, has the greatest impact on treatment preferences. This process is described in the Supplementary Methods.

Following the survey, two IQVIA moderators conducted qualitative individual interviews with the same 16 clinical experts to better understand their responses and the range of plausible values for expected treatment preferences and compliance (i.e., the minimum and maximum percentages of patients whom experts believed would prefer, adhere to, or persist with each treatment or treatment characteristic). The interviews also included exploration and refinement of their rankings for attributes of pill forms of ARPIs. Details of the interview process are described in the Supplementary Methods.

Following the interviews, two focus groups were conducted by two IQVIA moderators, who had not conducted the interviews but had been involved in the analysis, with the same clinical experts to assess the level of convergence on their perspectives. Details of how the focus groups were conducted can be found in the Supplementary Methods. Each focus group included six to eight participants, with a balance of oncologists and urologists to ensure diverse perspectives. Sessions were audio-recorded and transcribed verbatim.

To assess participants’ level of agreement with each treatment-related statement or factor, we used a structured consensus framework adapted from the 2024 Advanced Prostate Cancer Consensus Conference (APCCC) [23]. Consensus was defined as agreement by ≥ 75% of the panelists with the statement; if ≥ 90% of panelists agreed, the result was classified as “strong consensus.” The quantitative data gathered during the individual interviews and focus group discussions were analyzed descriptively. Qualitative data were analyzed using a thematic analysis approach to identify patterns and emergent themes. Themes were refined through triangulation by discussing the findings from each phase with participants in the subsequent phase.

Phase 3: Mathematical Construction of Probabilistic Model

Monte Carlo simulations were performed to obtain probability distributions for the percentage of patients expected to prefer each medication type based on expert opinion, both overall and for a given adherence value derived from the proportions observed in the survey results. Using data obtained from phase 2, we constructed a series of probabilistic models to characterize the distributions of treatment, preference, and adherence; to explore how preference varies by adherence ranking; and to assess the relationship between preference and adherence for the four specific medication examples. Details of the model can be found in the Supplementary Methods.

Ethics

The study was approved by the Mexico Center for Clinical Research (confirmation number: 24/013), an independent ethics and research committee. The research was conducted in accordance with the principles of the Declaration of Helsinki (1964) and its subsequent amendments. All participants provided informed consent to take part in the study and consent for their anonymized responses to be published.

Results

Targeted Literature Review

A total of 1303 records were identified, and 15 papers were ultimately included for data extraction (Supplementary Fig. 1, Supplementary Table 2). Findings from the TLR underscored the relevance of medication attributes, with size, shape [17, 24–26], and regimen [27, 28] playing key roles in influencing swallowability, patient comfort, and, ultimately, adherence. Simpler regimens were consistently related to a greater willingness to adhere [29], and across multiple patient populations, small tablets [17, 24–26], oval or round shapes [24], and capsule formulations [26] were favored. These preferences were especially pronounced in older adults [24] and those with dysphagia [25].

Participant Characteristics

Characteristics of the 16 SEE participants are described in Table 2. The majority of participants were based in Mexico City (n = 12, 75.0%). Almost half (n = 7, 43.8%) were between 41 and 45 years old and 68.8% (n = 11) had ≥ 11 years of clinical experience. Nearly all (n = 15, 93.8%) physicians practiced in both public and private settings. On average, 64.4% of participants’ time in public practice focused on PC treatment, with each physician treating an average of over 200 patients with PC per year.

Table 2.

Demographic and practice characteristics of physicians (N = 16)

Characteristic	n (%)
Age
35–40 years	3 (18.8%)
41–45 years	7 (43.8%)
46–50 years	3 (18.8%)
> 50 years	3 (18.8%)
City of residence
Mexico City	12 (75.0%)
Guadalajara	2 (12.5%)
Monterrey	1 (6.3%)
Mérida	1 (6.3%)
Years of practice
6–10 years	5 (31.3%)
11–15 years	5 (31.3%)
16–20 years	4 (25.0%)
> 20 years	2 (12.5%)
Practice type
Both public and private	15 (93.8%)
Only public	1 (6.3%)

Survey

Most participants considered medication characteristics influential for treatment preferences (n = 9, 56.3%), adherence (n = 11, 68.8%), and persistence (n = 10, 62.5%) (Supplementary Fig. 2) with oncologists more likely than urologists to rate these characteristics to be highly influential or somewhat influential on patients’ treatment preferences (oncologists: n = 6 [75.0%]; urologists: n = 3 [37.5%]), adherence (oncologists: n = 7 [87.5%]; urologists: n = 4 [50%]), and persistence (oncologists: n = 7 [87.5%]; urologists: n = 3 [37.5%]).

Across specialties, dosing frequency and total pill count were ranked as the attributes with the greatest perceived impact on patient adherence, while smaller pill size was also viewed as potentially improving treatment convenience (Fig. 2). Both specialties agreed adherence would be best supported by reducing dosing frequency and daily pill count. In addition, participants felt that making pills smaller could improve treatment convenience and potentially support adherence.

Fig. 2.

Influence of individual treatment characteristics on expected patient preferences. Max maximum, Min minimum

Individual Interviews

Treatment Persistence

During the individual interviews, eight of the 16 participants (50%) stated that pill size, coating, and dosing frequency are somewhat influential on treatment persistence, particularly among elderly patients. Although these pill characteristics do not appear to be primary determinants of treatment persistence, they may support it, particularly when other characteristics, such as ease of administration and swallowability, are favorable.

Treatment Adherence

When discussing factors associated with adherence, participants identified the number and the size of tablets, as well as swallowing difficulties as barriers. This perception was echoed by both oncologists and urologists. While most participants agreed that pill characteristics are not the main driver of treatment adherence, 11 out of 16 (68.8%) emphasized that these features play a meaningful role among elderly and vulnerable subgroups with PC, especially among those with comorbidities and cognitive decline. Gastric tolerability was also highlighted, with participants noting that uncoated pills could cause discomfort, especially over long treatment durations.

Participants who mentioned pill size and number often suggested that simpler regimens could improve adherence among older adults, who may be managing multiple medications. Cost and accessibility also emerged as influences that could outweigh considerations of pill size or frequency.

Between specialties, oncologists tended to focus on logistical barriers affecting adherence, such as the complexity of the regimen and pill management. Urologists were more likely to reference socioeconomic factors, including insurance coverage or access to free medications.

Treatment Preferences

All participants agreed that treatment efficacy is the top priority when asked what drives patient preferences for oral ARPIs. However, when treatments offer comparable efficacy, other factors, such as convenience, tolerability, and affordability, play a significant role in shaping patient choices.

One frequently cited challenge was tolerability. Participants often noted that patients tend to choose the option associated with fewer or milder side effects. Affordability and access also emerged as key factors, particularly in public healthcare settings or among lower-income populations. Participants also stressed the importance of comorbidities and social factors, particularly cognitive decline and lack of caregiver support, which often result in confusion about medication schedules and dosing.

Clinical Expert Review of Individual Characteristics of ARPIs

The review of aggregated survey data and post-survey estimates showed that capsules and tablets had similar influence scores when other characteristics were held constant, with little change after post-survey refinement (maximum average for tablets: baseline 64.1% and 64.2% post-survey). Additionally, tablets measuring 10 mm × 10 mm were seen as most acceptable both pre- and post-survey (maximum average: 79.7% at baseline; 76.4% post-survey). Preferences for two tablets per day also remained highly influential (maximum average: baseline 77.5%; post-survey 76.9%) (Supplementary Table 3).

In the individual interviews, the preference for once-daily dosing was considered most impactful, with influence estimates ranging from 61.8–87.1%. A threshold of two pills per day had influence estimates of 42.5–77.3% (Fig. 2). Additionally, the estimated preferences favored smaller (10 mm × 10 mm) and round-shaped pills (50.3–79.3% and 44.3–72.5%, respectively), both of which were linked to better adherence (Supplementary Table 4). After reviewing the pill attributes, participants compared the four hypothetical medications where multiple attributes were evaluated together (Table 1). When participants compared the four hypothetical medications, Medication 2 (four small tablets, once daily) tended to rank highest overall, with an estimated influence range of 45–75% (Fig. 3, Supplementary Fig. 3). Participants commonly cited its small pill size and once-daily dosing as favorable features, although some noted that taking four pills could still be perceived as burdensome. Medication 3 (two large tablets, once daily) was generally ranked second, with estimated influence ranging from 38.8–61.6%. Although these ranges overlapped, the overall ranking pattern suggested a preference for Medication 2, primarily because of its small pill size and once-daily dosing.

Fig. 3.

Medication rankings. a Experts’ opinions of percentage of patients who would prefer each medication type. Same order for oncologists and urologists separately. b Experts’ overall preference ranking of the four medication types. Average results from the 16 participant responses. Participants were asked to rank from 1‑most preferred to 4-least preferred. An average result closer to 1 indicates most preferred, while least preferred is closest to 4. *Range: lower (minimum) and higher (maximum) value responded

When participants were asked to rank the five pill attributes from most to least important to their patients, 10 (62.5%) ranked dosing frequency as the most important attribute, while 9 (56.2%) ranked reducing pill count as an important characteristic (Supplementary Fig. 4).

Focus Groups

The focus groups yielded consensus on nearly all topics related to ARPI characteristics and their influence on treatment adherence, persistence, and outcomes (Table 3). Focus group findings were consistent with earlier phases and showed strong consensus (100%) that once-daily dosing and smaller pill size were preferred, particularly for older patients and those with swallowing difficulties. Participants also ranked Medication 2, a profile with 4 small tablets taken once daily, with high agreement across groups (86–100% agreement across the groups). Supplementary Table 3 illustrates the estimated ranges of patient preferences for various pill characteristics. Across all topics explored, consensus was reached among participants, with no areas of unresolved disagreement identified.

Table 3.

Summary of consensus topics in focus groups

Agreement subject	Description	Level of consensus
Characteristics of new hormonal therapies	Agreement that daily dosing frequency and total number of pills per day are the most critical factors	100% agreement
Daily administration frequency	Agreement that oral therapies should focus on once-daily formulations	100% agreement
Total number of pills per day	Agreement that a lower number of pills per day is preferred	High consensus (Group 1: 86% agreement; Group 2: 100% agreement)
Pill size	Agreement that smaller pill sizes are preferred, given the advanced age of many patients with prostate cancer and potential swallowing difficulties	100% agreement
Proportional ranges for pill shape (Round versus Oblong)	Pill shape is less critical than other factors, with a slight preference for round pills	High consensus (Group 1: 100% agreement; Group 2: 86% agreement)
Proportional ranges for pill type (Tablet versus Capsule)	Agreement that the difference between tablet and capsule is not as important as other characteristics	100% agreement
Ranking of medication profiles (Medication 2: four small tablets, once daily)	High ranking for a medication profile with four small tablets taken once daily, preferred for improved adherence	High consensus (Group 2: 100% agreement; Group 1: 86% agreement)
Adherence rates for each medication profile	Agreement that patient adherence is influenced by factors including fear of cancer, trust in physicians, and medication access, which is a significant challenge in Mexico	Moderate consensus (Group 1: 100% agreement; Group 2: 71% agreement)
Impact of patient preferences on adherence	Agreement that efficacy is more important than patient preferences in medication adherence	Low-to-moderate probability
Impact of patient preferences on persistence	Agreement that long-term tolerability and convenience are crucial for ensuring patient persistence with oral hormone therapies	Moderate-to-high probability
Impact of lack of adherence on treatment outcomes	Agreement that lack of adherence significantly impacts treatment outcomes	100% agreement
Impact of lack of persistence on treatment outcomes	Agreement that lack of persistence significantly impacts treatment outcomes and survival	100% agreement

Consensus statements regarding adherence and persistence outcomes reflect expert agreement with established clinical evidence, not findings specific to this study population

Monte Carlo Simulation

In the comparison of the four medication types, Monte Carlo simulations predicted that the greatest percentage of patients would prefer Medication 2, while the lowest proportion would favor Medication 4 (Supplementary Fig. 5). Medication 2 was also predicted to have the greatest probability of patient adherence, while Medication 1 was predicted to have the lowest adherence (Supplementary Fig. 5).

A second set of Monte Carlo simulations evaluating the relationship between adherence and preference predicted that patients would likely prefer and adhere to Medication 2 followed by Medication 3 (Fig. 4).

Fig. 4.

Monte Carlo simulation of preference by adherence ranking. This plot presents a random sample of 10,000 simulated points

Discussion

This mixed-methods study found that, from the perspective of Mexican clinical experts, dosing frequency, pill count, and pill size are the ARPI attributes most likely to influence patient preferences and adherence when efficacy is comparable. Across study phases, simpler regimens and smaller pills were consistently viewed as more favorable, and the profile represented by Medication 2 (four small tablets, once daily) was generally preferred, followed by Medication 3 (two large tablets, once daily).

The TLR and expert elicitation phases were broadly consistent in suggesting that physical medication attributes may influence swallowability, comfort, and adherence. Across study phases, the total number of pills per day and dosing frequency were ranked as the most influential attributes, followed by pill size. Although Medication 2, a regimen involving four small tablets taken once daily, generally ranked highest overall, the overlap in estimated preference and adherence ranges indicates that differences between medication profiles were modest and should be interpreted cautiously.

In the qualitative interviews, clinical experts emphasized that when treatment effectiveness is comparable, convenience-related features such as daily dosing frequency, total number of pills per day, and pill size can potentially influence patient preferences and adherence, particularly among older adults, and those experiencing dysphagia, cognitive impairment, or polypharmacy. These observations align with previous studies. In a 2021 survey of healthcare workers in aged care facilities in Australia, only 39.0% of participants believed swallowing abilities were considered at the prescribing stage, with pill size (95.8%), polypharmacy (75.2%), and lack of alternative formulations (74.9%) contributing to the challenge of medical administration in older adults [30]. In additional studies of older patients, participants with dysphagia noted that larger tablets measuring 11 mm or 13 mm pose swallowing challenges [25]. Furthermore, studies have shown that increasing the size of same-shaped tablets demonstrated a decrease in swallowability [24]. Similarly, findings from a 2009 study of patients with depression indicated that 80.0% of patients preferred new formulations of more easily ingested orally disintegrating tablets [31].

Pill shape and form type were generally viewed as less critical to patient preferences when other attributes, particularly pill size and ease of swallowing, were already favorable; however, some participants acknowledged that round shapes were marginally preferred for swallowability. In line with these observations, a prior study of patients in pain centers concluded that the ideal tablet is small and white, strongly arched circular, and coated, but if tablets are to be larger, they should be oblong, or oval with a coating [26].

Participants in this study consistently highlighted regimen simplicity and pharmaceutical design as factors they perceived to improve adherence. Prior research also suggests that structured adherence support, including pharmacist programs, reminders, and monitoring, may mitigate regimen complexity, suggesting combined formulation and support strategies are advisable [32]. Together, our findings suggest that patient-friendly characteristics may support treatment convenience and may be perceived as facilitating adherence. These findings may have implications for the design of oral ARPIs and support consideration of patient preferences into formulation and treatment choice discussions.

Limitations

The results of this study should be interpreted carefully prior to generalizing the findings to other contexts. All data rely on clinicians’ derived estimates rather than direct patient-reported outcomes, with a small and highly selected sample size. Individual patient characteristics and preferences should be considered when applying these findings in practice. While clinical experts offer valuable insights into patient behavior, their opinions are inherently influenced by clinical impressions, recall bias, and professional assumptions based on their patients’ behaviors and attitudes. Future research should seek to engage patients directly regarding their preferences.

In addition, this study reflects the perspectives of a targeted group of 16 Mexican oncologists and urologists. While the study provides compelling insights into modifiable treatment features that support patient adherence and persistence, the extent to which these findings apply beyond Mexico will depend on the healthcare infrastructure, cultural norms, and population demographics of each local context. In addition, though participants were blinded, prior experience with ARPIs may have allowed them to infer which treatments were being described. Furthermore, clinician interviews may also be influenced by social desirability bias, whereby participants may over-report consideration of patient preferences relative to real-world practice [33]. To minimize bias, participants were blinded to which specific medications/active principles were being evaluated during the study. Despite blinding, participants’ prior experience of ARPIs may have allowed them to infer which treatments were being described, potentially influencing their response. Participant race/ethnicity was not collected despite its relevance to PC risk. As this study relied on clinician perspectives, future research should include patient experience data to strengthen these insights.

Conclusions

This study highlights clinicians’ perspectives on potential influence of physical attributes of oral ARPIs, such as pill count, dosing frequency, and pill size on patients’ PC treatment preferences, adherence, and persistence. Experts generally identified simpler, more patient-preferred regimens as potentially more usable in clinical practice, particularly for those experiencing dysphagia, cognitive impairment, or polypharmacy. Future studies should directly assess patient perceptions of these treatment characteristics.

Supplementary Information

Below is the link to the electronic supplementary material.

Author Contributions

Writing—reviewing and editing: Mario Escobar Gómez, Ana Maria Rodríguez-Leboeuf, Selene Camargo-Correa, Ida Caterina García-Appendini, Arti Dhar, Isabela Rivas, Juan Guillermo Ariza, Pedro A. Madero-Morales; Acquisition and interpretation of study data: Mario Escobar Gómez, Selene Camargo-Correa, Ida Caterina García-Appendini, Isabela Rivas, Juan Guillermo Ariza, Pedro A. Madero-Morales; Study design: Ana Maria Rodríguez-Leboeuf, Arti Dhar; Qualitative analysis: Selene Camargo-Correa. All authors reviewed and approved the final manuscript and agreed to be accountable for all aspects of the work. All authors meet the International Committee of Medical Journal Editors criteria for authorship.

Funding

This study was funded by Astellas Pharma Inc. Employees of the sponsor were involved in the study design, execution, analysis, and reporting of the data. The authors maintained control of the content and the decision to publish. The journal’s Rapid Service Fee was funded by Astellas Pharma Inc.

Data Availability

All data generated or analyzed during this study, which support the findings of this study, are included within this article and its supplementary information files. Researchers interested in further analyses not presented in the manuscript may contact the corresponding author.

Declarations

Conflict of Interest

Ana Maria Rodríguez-LeBoeuf, Selene Camargo-Correa, and Ida Caterina García-Appendini are employees of IQVIA and received funding from Astellas to conduct this study. Arti Dhar, Isabela Rivas, and Juan Guillermo Ariza reported employment with Astellas. Mario Escobar Gómez and Pedro A. Madero-Morales have no conflicts of interest to report.

Ethical Approval

The study was approved by the Mexico Center for Clinical Research (confirmation number: 24/013), an independent ethics and research committee. The research was conducted in accordance with the principles of the Declaration of Helsinki (1964) and its subsequent amendments. All participants provided informed consent to take part in the study and consent for their anonymized responses to be published.