Humira (adalimumab) is a biologic medication used to treat several severe autoimmune conditions, including rheumatoid arthritis, Crohn’s disease, and plaque psoriasis. Its high price tag has created a significant financial burden on the healthcare system and for patients. Competition is highly anticipated for patients seeking more affordable treatment options. This competition comes from biosimilars, a new class of medicine that serves as the biological equivalent of a generic drug. The launch of these products addresses the need for cost reduction while maintaining quality of care.
Understanding Biosimilars: The Generic Equivalent
Traditional generic drugs are chemically synthesized and are exact copies of their brand-name counterparts. Biosimilars are complex protein-based medications derived from living systems, making them impossible to replicate exactly. The Food and Drug Administration (FDA) requires manufacturers to demonstrate that a biosimilar is “highly similar” to the reference product, with no clinically meaningful differences.
This regulatory pathway is abbreviated compared to the original drug’s approval process, allowing manufacturers to rely on the FDA’s existing findings of safety and effectiveness for the reference product. The process involves extensive analytical, nonclinical, and clinical studies to confirm the biosimilar has the same safety profile and effectiveness. An even higher designation is “interchangeability,” meaning the FDA has confirmed the biosimilar can be substituted for the reference product with the same expected clinical result. This designation allows a pharmacist to dispense the biosimilar instead of Humira without the prescriber’s specific permission, depending on state pharmacy laws.
The Humira Biosimilar Launch Timeline
The availability of a generic Humira was determined by complex legal strategy rather than scientific readiness. Humira’s manufacturer established a large network of patents, often called a “patent thicket,” which extended the drug’s market exclusivity in the United States. Biosimilar manufacturers were required to enter into confidential settlements to establish specific US launch dates, even after receiving FDA approval.
This legal maneuvering resulted in a staggered launch schedule beginning in 2023. The first Humira biosimilar to enter the US market was Amjevita (adalimumab-atto), which launched on January 31, 2023, under a negotiated settlement. Amjevita was the sole competitor until the largest wave of competitors launched approximately six months later, beginning in July 2023. This second wave introduced many major competitors, fundamentally changing the adalimumab market.
Key Biosimilars and Their Distinctions
The numerous adalimumab biosimilars now available present a range of options that differ in practical ways. A primary distinction is the drug’s concentration. The original Humira was a low-concentration (LC) formulation, but the later, preferred version is a high-concentration (HC) formulation. The HC formulation delivers a 40 mg dose in a smaller volume (0.4 mL instead of 0.8 mL), which can reduce injection time and discomfort.
Formulation Differences
Another difference is the presence of citrate in the formulation. Citrate is an inactive ingredient that can cause a burning sensation at the injection site, and newer formulations of Humira and most biosimilars are now citrate-free. Biosimilars like Yuflyma (adalimumab-aaty) launched exclusively with the preferred high-concentration, citrate-free formulation. Others, such as Hadlima (adalimumab-bwwd) and Hyrimoz (adalimumab-adaz), are available in both low- and high-concentration options.
Interchangeability Status
The interchangeability designation further distinguishes the products, as it affects how they can be substituted at the pharmacy level. Cyltezo (adalimumab-adbm) was the first adalimumab biosimilar to receive this designation from the FDA, and Abrilada (adalimumab-afzb) has also achieved this status. This designation indicates the product has passed additional switching studies demonstrating that patients can safely move back and forth between the reference product and the biosimilar. This status offers greater flexibility in prescribing and dispensing.
Practical Impact: Cost, Insurance, and Switching
The availability of biosimilars has created a complex pricing structure designed to appeal to different parts of the healthcare system. Many manufacturers adopted a dual-pricing strategy, offering one version with a list price close to Humira’s and another with a significantly lower list price, sometimes discounted by 85% or more. This difference between the high list price and the lower net price is heavily influenced by rebates.
Pharmacy Benefit Managers (PBMs) manage prescription drug benefits for insurance plans and control which drugs are covered. PBMs often favor the brand-name drug or biosimilars with a higher list price because the associated rebates generate more revenue. This rebate system has slowed the adoption of the lowest-cost biosimilars, meaning the largest potential savings have not yet been fully realized.
Patients should understand that biosimilar availability does not guarantee they will receive it. Coverage depends entirely on their specific insurance plan’s formulary, the list of approved drugs. Insurers may require patients stable on Humira to switch to a preferred biosimilar, or Humira may remain the preferred option due to PBM arrangements. Patients should consult their physician regarding formulation advantages and contact their insurance provider to confirm coverage and out-of-pocket costs.