Insights into adherence to cladribine tablets in the real world in multiple countries: results from patient support programs

Background: Patient support programs (PSP) help initiate and maintain disease-modifying treatment (DMT) for people with multiple sclerosis (PwMS). adveva ® (worldwide), Alcura Healthcare (Netherlands), and MS LifeLines ® (US) are nurse–pharmacy-led PSPs that collect clinical information, with consent, on PwMS receiving cladribine tablets (3.5 mg/kg over 2 years followed by a 2-year treatment-free period per product label). Objective: To evaluate initiation and completion of short courses of cladribine tablets treatment in Years 1 and 2 for PwMS and the frequency of subsequent treatment. Design: Retrospective, multinational, observational study using real-world data from PSPs. Methods: Clinical data from PSPs in Australia, Canada, Gulf, Latin America, Near East, Netherlands, UK, and US (December 2017–December 2023) included prior DMT use, cladribine tablets initiation and completion (Years 1 and 2), and subsequent treatment after Year 2 for those with ⩾48 months’ follow-up. Results: Across all PSPs, 22,082 PwMS initiated cladribine tablets (Australia, n = 799; Canada, n = 3665; Gulf, n = 258; Latin America, n = 1854; Near East, n = 86; Netherlands, n = 681; UK, n = 2320; US, n = 12,418), of whom 70.9%–81.3% were female (mean age 34.2–49.1 years). Most were DMT-experienced (Australia, no contribution to analysis; Canada, 100%; Gulf, 52.7%; Latin America, 57.7%; Near East, 86.0%; Netherlands, 81.4%; UK, 30.0%; US, 79.5%) with oral DMTs most commonly used (36.5%–69.3%). In PwMS with ⩾18 months’ follow-up, ⩾82.8% initiated Year 2 treatment at a mean of 12.4 (±3.8) to 13.9 (±3.5) months after initiating Year 1 treatment. Of those commencing Year 2 treatment, ⩾93.6% completed it. Additional treatment with cladribine tablets beyond 48 months was administered in a small proportion of PwMS: Canada, 5.6%; Latin America, 4.3%; Netherlands, 3.8%; and UK, 1.8%. Conclusion: Cladribine tablets adherence was high, with most PwMS completing short-course cladribine tablets treatment in Years 1 and 2. Of those with ⩾48 months’ follow-up, only a small proportion received additional cladribine tablets treatment.