Evaluating Patients' Preferences Regarding Treatment Options for Waldenström's Macroglobulinemia, a Discrete-Choice-Experiment
Authors: Amaador Karima , Nieuwkerk Pythia , Minnema Monique C. , Kersten Marie José , Vos Josephine M.I. 
Published: November 2021

Abstract
Introduction
The management of Waldenström's Macroglobulinemia (WM), a rare and incurable B-cell non-Hodgkin lymphoma, has evolved in recent years. Treatment options are increasing including more modern targeted therapies. Therefore there are currently several effective treatment options available for WM. There is no consensus on a preferred treatment. Widely used treatment options include rituximab combined with chemotherapy, proteasome inhibitors, and the oral BTK inhibitor ibrutinib. These treatments have varying properties in terms of efficacy, toxicity profile, duration (fixed-duration vs long-term maintenance), administration (oral vs intravenous/subcutaneous (IV/SC)), and type of agent (chemotherapy vs targeted therapy). A better understanding of patients' treatment preferences could aid physicians in developing an individualized treatment plan. Also, a better insight in patients' treatment views could help direct future clinical studies in WM. However, treatment preferences of WM patients have not been investigated. We aimed to evaluate treatment preferences of WM patients by means of a discrete choice experiment (DCE) and to assess the importance of different attributes describing the currently available treatment regimens.
Methods
A mixed-method approach, consisting of a literature review, qualitative interviews and expert discussions was utilized for identification and selection of attributes/levels. A DCE questionnaire was developed in Dutch and included 5 treatment-related attributes: 5-year progression-free survival (PFS), frequency/route of administration(IV/SC or oral)/setting (clinic or home) of treatment, adverse events (nausea & vomiting and fatigue, neuropathy and atrial fibrillation), risk of future secondary malignancies (low vs high), and type of treatment agent (chemotherapy or targeted therapy). Each respondent was presented with 16 choice cards and was asked to choose between two hypothetical but realistic treatment options (see Figure 1 for an example). A pilot DCE study was carried out in 5 patients to evaluate feasibility.
Data were collected via a nationwide online questionnaire via the patient organizations' website and via paper-based questionnaires sent to the participants known at the outpatient clinic. An orthogonal design was used to construct the choice tasks and a mixed logit panel data model was used to assess patients' preferences and trade-offs between attributes/levels.
Results
A total of 330 online questionnaires and 17 paper-based questionnaires were returned. After excluding incomplete survey data, 214 (65%) questionnaires were included for data analysis, respondents characteristics are presented in Table 1. The 5-year PFS followed by the risk of secondary malignancies were the most important attributes for making treatment decisions. The probability of choosing a treatment option increased with 26% and 22% if the 5-year PFS increased from 50% to 70% and if the chance of future secondary malignancies was decreased from "high risk" to "low risk", respectively. Of the adverse events, patients disliked being at risk for neuropathy the most more than nausea, vomiting and extreme fatigue. Patients were willing to give up 7,2% treatment efficacy to avoid risk of neuropathy. The probability of choosing a treatment option increased with 8% for a fixed-duration treatment with IV/SC administration at the hospital compared to an ongoing daily oral regimen at home (Table 2). Socio-demographic characteristics such as age, gender and treatment status did not significantly influence patients' preferences with the exception of educational status. Lower 5-year PFS was more acceptable for patients with higher education (P&lt;0.0001 ) and this subgroup of patients preferred a treatment with targeted therapy and low risk of secondary malignancy (P&lt;0.0001).
Conclusion
These are the first data on WM patients' preferences on treatment characteristics. We found that Dutch WM patients find efficacy (high 5-year PFS rate) the most important attribute, followed by a low risk of future secondary malignancies. Neuropathy was the adverse event they most wanted to avoid. They preferred a fixed-duration IV/SC treatment over an ongoing oral regimen. These data can be used in discussions with individual patients about their treatment preference, and help direct future clinical trials that optimally connect to WM patients' preferences.
Figure 1 Figure 1.

Disclosures
Minnema: Cilag: Consultancy; Janssen: Consultancy; Celgene: Other: Travel expenses; Alnylam: Consultancy; BMS: Consultancy; Kite/Gilead: Consultancy. Kersten: Miltenyi Biotec: Consultancy, Honoraria, Other: Travel support; Roche: Consultancy, Honoraria, Other: Travel support, Research Funding; Novartis: Consultancy, Honoraria, Other: Travel support; BMS/Celgene: Consultancy, Honoraria; Takeda: Research Funding; Celgene: Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support, Research Funding. Vos: Celgene: Other: Travel reimbursement; Sanofi: Membership on an entity's Board of Directors or advisory committees.