When Cost Savings Aren't Really Savings: The Hidden Economics of Non-Medical Switching in Ankylosing Spondylitis

As PBMs, payers, employers, and health systems increasingly adopt biosimilars to manage costs, it is critical to distinguish between two fundamentally different patient populations: treatment-naïve patients and stable patients on established therapy. While many biologic agents, both originators and biosimilars, are used across autoimmune diseases, ankylosing spondylitis (AS or SpA) presents unique risks when disease control is disrupted. AS is a chronic autoimmune disorder that primarily affects the spine and sacroiliac joints, causing progressive pain, stiffness, and structural damage; loss of control can result in irreversible spinal or hip fusion, severe chronic pain, and permanent, life-altering mobility impairment.

This issue is not academic for me.

I have ankylosing spondylitis and have been clinically stable on Humira (adalimumab) for three plus years — a stability achieved through evidence-based care and it has changed my life thanks to Brian Horgan, PA-C and AHN Rheumatology. Yet despite sustained disease control, I continue to face pressure to switch therapies from PBMs for non-medical reasons, reinforcing why advocacy grounded in clinical evidence matters for patients beyond my own experience.

What the Evidence and Guidelines Say

The 2019 American College of Rheumatology(ACR), Spondylitis Association of America(SAA), and Spondyloarthritis Research and Treatment Network (SPARTAN) guidelines provide a strong recommendation against mandated non-medical switching from originator TNF inhibitors to biosimilars in patients with stable ankylosing spondylitis.[1] This isn't about biosimilar efficacy — it's about the clinical risks of non-medical switching in patients who have achieved disease control.

What the Data Shows:

• The ABILITY-3 Trial showed 53% of patients who discontinue Humira (adalimumab) experience disease flare, and critically, 44% NEVER regain disease remission upon retreatment. This is real risk if the biosimiliar is ineffective [2]
• Real-world studies demonstrate that non-medical switching is associated with reduced remission rates from 92.7% to 80.9%, with some biosimilars showing[3] 12-month drug survival rates as low as 73% compared to 90% for others [4]
• Non-Medical switching increases total healthcare costs by ~$4,000 per patient per year, with healthcare resource utilization rising[5] 4-37% post-switch, potentially[6] offsetting any drug cost savings
• Moreover, 80% of AS costs are work-related productivity losses — disease flares drive disability and employee absenteeism, not just medical expenses [7]

The Right Approach:

✅ Biosimilars as first-line therapy in treatment-naïve patients supported by comparable efficacy data
✅ Biosimilars after treatment failure or intolerance = appropriate clinical indication with viable opportunity
❌ Mandated switching in stable patients introduces unnecessary clinical risk without clear benefit and risk “breaking” what is “fixed”

A Call for Attention from the Stakeholders

The goal should be sustainable cost management, not short-term drug cost reduction that increases downstream utilization. Shared decision-making between physicians and patients (not administrative mandates) should guide treatment decisions in stable patients.

Key Stakeholders:

• PBMs: Express Scripts Pharmacy Benefit Services, CVS Caremark, Optum Rx, Prime Therapeutics
• Specialty Pharmacies: CVS Specialty, Walgreens Boots Alliance, Optum Specialty Pharmacy, Accredo Specialty Pharmacy, Amber Specialty Pharmacy, Avella Specialty Pharmacy, Senderra Specialty Pharmacy
• Manufacturers: AbbVie, Amgen, Samsung Bioepis, Sandoz, Boehringer Ingelheim, Pfizer, Coherus BioSciences, Organon, Mark Cuban Cost Plus Drug Company, PBC 

I would like to give special commendation and recognition to Rightway Healthcare and Jordan Feldman, who are leading new disruptive PBM approaches and recognized a unique recognition path forward with exception in this disease state in their biosimilar strategy.

Evidence-based formulary design should recognize that:

• Treatment-naïve patients are ideal candidates for biosimilar initiation
  Stable patients on originator biologics face real clinical risks from non-medical switching
• Total cost of care includes flares, work disability, and healthcare resource utilization

The majority of US physicians (84%) oppose non-medical switching in stable patients, with concerns about treatment efficacy (57%), patient safety (53%), and mental health impacts (59%) especially in AS/SpA.[8]

Let's align Payer and PBM policy with clinical evidence and guidelines. Biosimilars have an important role in healthcare, but that role should be defined by medical appropriateness, not blanket switching mandates in the absence of the full economic picture.

References

1. Ward MM, Deodhar A, Gensler LS, et al. 2019 Update of the American College of Rheumatology/Spondylitis Association of America/Spondyloarthritis Research and Treatment Network Recommendations for the Treatment of Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis. Arthritis & Rheumatology. 2019. 

2. Landewé R, Sieper J, Mease P, et. al. Efficacy and safety of continuing versus withdrawing adalimumab therapy in maintaining remission in patients with non-radiographic axial spondyloarthritis (ABILITY-3): a multicentre, randomised, double-blind study. Lancet. 2018 Jul 14;392(10142):134-144. doi: 10.1016/S0140-6736(18)31362-X. Epub 2018 Jun 29.

3. Scrivo R, Castellani C, Mancuso S, et al. Effectiveness of Non-Medical Switch From Adalimumab Bio-Originator to SB5 Biosimilar and From ABP501 Adalimumab Biosimilar to SB5 Biosimilar in Patients With Chronic Inflammatory Arthropathies: A Monocentric Observational Study. Clinical and Experimental Rheumatology. 2023. 

4. Glintborg B, Loft AG, Omerovic E, et al. To Switch or Not to Switch: Results of a Nationwide Guideline of Mandatory Switching From Originator to Biosimilar Etanercept. One-Year Treatment Outcomes in 2061 Patients With Inflammatory Arthritis From the DANBIO Registry. Annals of the Rheumatic Diseases. 2019. 

5. Wolf D, Skup M, Yang H, et al. Clinical Outcomes Associated With Switching or Discontinuation From Anti-TNF Inhibitors for Nonmedical Reasons. Clinical Therapeutics. 2017. 

6. Liu Y, Skup M, Yang M, Qi CZ, Wu EQ. Discontinuation and Switchback After Non-Medical Switching From Originator Tumor Necrosis Factor Alpha (TNF) Inhibitors to Biosimilars: A Meta-Analysis of Real-World Studies From 2012 to 2018. Advances in Therapy. 2022. 

7. Cooksey R, Husain MJ, Brophy S, et. al. The Cost of Ankylosing Spondylitis in the UK Using Linked Routine and Patient-Reported Survey Data. PLoS One. 2015 Jul 17;10(7):e0126105. doi: 10.1371/journal.pone.0126105. PMID: 26185984; PMCID: PMC4506082.

8. Teeple A, Ellis LA, Huff L, et al. Physician Attitudes About Non-Medical Switching to Biosimilars: Results From an Online Physician Survey in the United States. Current Medical Research and Opinion. 2019.