Report Highlights

U.S. Sacroiliitis Treatment: Market Overview

The U.S. sacroiliitis treatment market is structured around three core therapeutic pillars: pharmacological management led by NSAIDs and biologic disease-modifying antirheumatic drugs (bDMARDs), interventional procedures including corticosteroid injections and minimally invasive sacroiliac joint fusion, and physical rehabilitation services. Government policy has been the dominant shaping force through Medicare and Medicaid reimbursement schedules, FDA approval pathways, and the Affordable Care Act's elimination of annual benefit caps — which expanded specialist access for an estimated 1.3 million Americans diagnosed with axial spondyloarthritis, the primary driver of sacroiliitis. The private sector has led investment in biologic innovation and medical device development.

Market structure is fragmented at the therapy level but increasingly consolidated among biologic manufacturers. The FDA's approval of multiple IL-17A inhibitors — including Cosentyx (secukinumab) and Taltz (ixekizumab) — for non-radiographic axial spondyloarthritis has created a competitive biologics tier directly targeting sacroiliitis pathology. CMS sets the reimbursement ceiling for the majority of treatment encounters, with Medicare Part B covering most administered biologics under the buy-and-bill model. The interplay between FDA label expansions, CMS coverage determinations, and commercial payer prior authorization policies defines the market's growth trajectory more than any single clinical or commercial factor.

Policy-Driven Growth in Sacroiliitis Treatment

Three specific policy mechanisms are generating direct demand expansion in this market. First, the FDA's 2020 approval of secukinumab and 2019 approval of ixekizumab for non-radiographic axial spondyloarthritis — a condition where sacroiliitis is the hallmark finding — created a clinically validated and reimbursable treatment pathway for an estimated 500,000 previously untreated patients. These label expansions operate as demand catalysts by enabling prescribers to justify biologic initiation to payers with regulatory backing, triggering commercial and Medicare prior authorization approvals that were previously unavailable. Each approved label expansion directly enlarges the reimbursable patient pool, producing a measurable step-up in prescription volumes within 12 to 18 months of approval.

Second, the Inflation Reduction Act of 2022 (IRA), administered through CMS, introduced Medicare drug price negotiation and out-of-pocket cap provisions — capped at USD 2,000 annually under Part D from 2025 — reducing patient cost-sharing barriers for high-cost biologics. This directly improves adherence rates among Medicare-eligible sacroiliitis patients who previously abandoned therapy due to cost. Third, CMS's Hospital Outpatient Prospective Payment System (OPPS) final rules have progressively reimbursed minimally invasive SI joint fusion procedures under Ambulatory Payment Classifications, incentivising outpatient procedure volumes and driving adoption of devices manufactured by SI-BONE and Enovis. The 2023 OPPS final rule confirmed continued coverage, providing multi-year revenue predictability for device manufacturers.

Regulatory Barriers and Compliance Costs

The most significant regulatory barrier is the FDA's rigorous biologic approval pathway under 21 CFR Part 601, which requires large-scale Phase III randomised controlled trials specific to sacroiliitis or its parent condition — axial spondyloarthritis. Clinical programmes of this scale typically require USD 400–800 million in development expenditure and eight to twelve years from IND filing to approval. The FDA's Center for Drug Evaluation and Research (CDER) additionally requires postmarket safety surveillance commitments under Risk Evaluation and Mitigation Strategies (REMS) for certain immunomodulatory biologics, adding ongoing pharmacovigilance costs estimated at USD 2–5 million annually per approved product. These barriers concentrate market power among large-capitalisation pharmaceutical companies and effectively exclude smaller innovators from the biologics segment.

Commercial payer prior authorisation requirements, while not a federal regulatory mechanism, function as a compliance cost embedded in the market structure. The American Medical Association has documented that rheumatologists spend an average of 14.6 hours per week on prior authorisation administration — a burden disproportionately concentrated in sacroiliitis and spondyloarthritis biologics due to step-edit requirements mandating NSAID failure before biologic initiation. CMS's 2024 proposed rule on prior authorisation transparency under 42 CFR Parts 422 and 423, targeting Medicare Advantage plans, is designed to reduce approval timelines from the current industry average of 10.7 days to under 72 hours for urgent requests. Full compliance is mandated by January 2026, which will materially reduce access friction for sacroiliitis biologic prescriptions.

Policy-Created Opportunities in U.S. Sacroiliitis Treatment

The CMS Merit-based Incentive Payment System (MIPS) under the Quality Payment Program (QPP) creates a direct financial incentive for rheumatologists to document disease activity scores and treatment escalation decisions — practices that systematically identify undertreated sacroiliitis patients and route them toward biologic or interventional therapy. Rheumatology practices reporting on MIPS quality measures related to functional status assessment and disease-modifying therapy initiation receive positive payment adjustments of up to 9% of Medicare fee schedule payments. This administrative incentive structure is effectively a demand-generation mechanism that increases biologic initiation rates independent of direct pharmaceutical marketing, creating volume growth that benefits all biologic manufacturers with active Medicare formulary coverage.

The National Institutes of Health's National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) has allocated sustained funding under its Strategic Plan 2023–2027 toward research on sacroiliac joint inflammation biomarkers and novel treatment targets. This public investment creates an early-stage pipeline opportunity for companies developing small-molecule JAK inhibitors or next-generation IL-23 inhibitors with sacroiliitis-specific labelling. Additionally, the 340B Drug Pricing Program administered by the Health Resources and Services Administration (HRSA) enables qualifying covered entities — including federally qualified health centres serving lower-income sacroiliitis patients — to purchase biologics at significant discounts, expanding treatment access in underserved populations and creating incremental volume for participating manufacturers.

Market at a Glance

Leading Market Participants

• AbbVie Inc.
• Novartis AG
• UCB S.A.
• Eli Lilly and Company
• Johnson & Johnson (Janssen)
• Pfizer Inc.
• SI-BONE Inc.
• Enovis Corporation
• Globus Medical Inc.
• Teva Pharmaceutical Industries

Regulatory and Policy Environment

The primary legislative framework governing this market is the Biologics Price Competition and Innovation Act of 2009 (BPCIA), enacted as part of the Affordable Care Act (Public Law 111-148), administered by the FDA's CDER and Center for Biologics Evaluation and Research (CBER). The BPCIA established the 351(k) biosimilar approval pathway, which directly shapes competitive dynamics in the sacroiliitis biologics market by enabling Humira biosimilar entry — with 10 biosimilars now approved including Hadlima, Hyrimoz, and Cyltezo. The Inflation Reduction Act of 2022 adds a further regulatory layer by subjecting high-expenditure Medicare drugs, including biologics used in sacroiliitis, to price negotiation beginning 2026, with Enbrel (etanercept) among early negotiation candidates. Compared to the European Medicines Agency's centralised biosimilar pathway, the FDA's framework has produced faster multi-biosimilar market entry but slower originator price erosion due to patent settlement agreements known as "pay-for-delay" arrangements under FTC scrutiny.

Upcoming regulatory changes with confirmed or expected timelines include: FDA finalisation of real-world evidence guidance under the 21st Century Cures Act by 2026, which will allow sacroiliitis biologic manufacturers to use registry data to support label expansion without full Phase III trials, materially reducing development costs for new indications. CMS's mandatory prior authorisation transparency rule under 42 CFR Parts 422 and 423 takes full effect January 2026 for Medicare Advantage plans, requiring electronic prior authorisation and decision turnaround within 72 hours. The FTC's ongoing enforcement against pharmaceutical pay-for-delay settlements — most recently its 2023 action against AbbVie — is expected to accelerate biosimilar penetration in sacroiliitis biologics by 2027, fundamentally repricing the market's dominant TNF-alpha inhibitor segment and shifting prescriber and payer preferences toward IL-17A and IL-23 inhibitors not yet facing biosimilar competition.

Long-Term Policy Outlook for U.S. Sacroiliitis Treatment

By 2032, the most consequential policy shift reshaping this market will be the full implementation of IRA drug price negotiation across the biologics tier. CMS's negotiated prices for selected Medicare Part D drugs — including biologic agents used in sacroiliitis — will compress manufacturer net revenue per unit while simultaneously improving patient affordability and adherence, producing a volume-price trade-off that favours market participants with high prescription volumes and diversified payer exposure. The IRA's out-of-pocket cap structure is projected by the Congressional Budget Office to increase biologic adherence by 12–18% among Medicare-eligible patients, directly expanding treatment continuity revenues for manufacturers positioned in the formulary at negotiated prices. Companies that fail to secure formulary inclusion under negotiated terms face volume losses that outweigh any short-term unit price preservation strategy.

The second major policy trajectory is the expansion of CMS coverage for minimally invasive sacroiliac joint fusion, with an expected 2027–2028 update to OPPS reimbursement rates reflecting the growing clinical evidence base. NIAMS-funded outcomes research on SI joint fusion, if published by 2026 in alignment with the 2023–2027 Strategic Plan, will provide the clinical validation needed for CMS to broaden coverage beyond current restrictions to patients with confirmed sacroiliac joint dysfunction secondary to sacroiliitis. This coverage expansion will create a structural demand shift from pharmacological-only management toward combination pharmacological and procedural pathways, increasing average revenue per patient episode and benefiting both biologic manufacturers and SI fusion device companies simultaneously through parallel treatment adoption rather than competitive substitution.