Early Success of Adalimumab Biosimilars Featured at AMCP 2025

The early adoption of adalimumab biosimilars in the US health care landscape presents key considerations for managed care stakeholders evaluating coverage decisions, patient access, and long-term cost management strategies. Two recent retrospective studies, presented as posters at the Academy of Managed Care Pharmacy annual meeting (AMCP 2025), provide important insights into these factors, highlighting adherence, comparable outcomes, and cost savings.1,2

The first study examined patient characteristics, treatment history, and early outcomes following initiation of adalimumab-adaz (Hyrimoz), a biosimilar to Humira (reference adalimumab) launched in July 2023.1 Using Komodo Research Data, researchers conducted a retrospective cohort analysis of 23,737 individuals who initiated treatment through May 2024. Over half (53.5%) of the patients began treatment in April 2024, coinciding with formulary changes favoring biosimilar options. Most patients were female (59.4%), White (73.5%), and commercially insured (91.0%), with a median age of 49 years.

The biosimilar was primarily prescribed for rheumatoid arthritis (33.0%), Crohn disease (23.2%), and psoriatic arthritis (15.7%). Nearly all patients (93.2%) had received prior biologic treatment, with 98.2% having used the reference adalimumab product. In the year preceding initiation, common comorbidities included hyperlipidemia, hypertension, and anxiety, while corticosteroids, nonsteroidal anti-inflammatory drugs, and conventional disease-modifying antirheumatic drugs were frequently used as adjunct therapies.

A subset of 1,108 patients with 3 months of continuous enrollment was included in persistence and adherence analyses. Persistence at 3 months was 65.7%, with most treatment changes attributed to switching between adalimumab products rather than true discontinuation. Adherence to adalimumab-adaz remained high throughout the study period, as demonstrated by an average proportion of days covered (PDC) of 93.9%, indicating that patients consistently maintained their prescribed treatment regimen with minimal interruptions.

The findings suggest that initial adoption of adalimumab-adaz occurred largely among treatment-experienced individuals and was influenced by formulary-driven product switching. Despite moderate early persistence, high adherence rates underscore the viability of biosimilars in supporting continuity of care.

The second study, conducted within Kaiser Permanente health plans in California and Colorado, assessed clinical and financial outcomes for patients with rheumatoid arthritis who transitioned from reference adalimumab to adalimumab-atto (Amjevita), the first biosimilar to launch in the US in early 2023.2 The study employed a retrospective, propensity score-matched design, comparing 1,172 biosimilar switchers to 1,172 control patients who remained on the originator product. Most patients were female (78%) with a mean age of 58 years, and approximately 60% had at least 2 years of prior reference adalimumab use.

The primary outcome, a composite measure of disease worsening, occurred in 24.8% of the biosimilar group compared to 31.0% of the control group. The biosimilar was found to be non-inferior in clinical effectiveness (P < .01). Safety outcomes, including serious infection, cancer, or injection-related adverse events, were also comparable (5.6 vs 7.2 events per 100 person-years; P = .21). Importantly, patients who switched to the biosimilar experienced significantly lower monthly out-of-pocket costs for adalimumab (P < .01), highlighting a tangible financial benefit.

The findings emphasize the potential for biosimilar adoption to optimize therapeutic value, reduce patient financial burden, and support sustainable formulary management. The authors concluded that more research with extended follow-up will be crucial in understanding long-term outcomes, especially as payer-driven transitions become more widespread.

References

1. Bungay R, Chen A, Gagnon-Sanchagrin, et al. Real-world patient profile, persistence, and adherence data on early Hyrimoz utilization: a retrospective claims-based analysis. Presented at: AMCP 2025; March 31-April 3, 2025; Houston, TX. Poster M2.

2. Pham C, Niu F, Delate T, et al. Clinical and out-of-pocket cost outcomes of patients with rheumatoid arthritis who switched to biosimilar adalimumab-atto from reference product adalimumab. Presented at: AMCP 2025; March 31-April 3, 2025; Houston, TX. Poster M3.