The Core Difference: Biosimilar vs. Reference Product
At the heart of the distinction between Amjevita and Humira is their classification as a biosimilar versus a reference biologic product. Humira (adalimumab) is the original, brand-name biologic drug, first approved by the FDA in 2002. Biologic medications are complex, made from living organisms or cells, making them impossible to replicate exactly like traditional chemical generics. Instead, manufacturers can create biosimilars.
Amjevita (adalimumab-atto) is the first FDA-approved biosimilar of Humira, launched in the United States in 2023. To gain approval, Amjevita was required to demonstrate that it is 'highly similar' to Humira and has 'no clinically meaningful differences' in safety, purity, and potency. While not an exact clone, the functional similarity ensures that patients can expect the same therapeutic outcomes.
Why are biosimilars important?
Biosimilars introduce market competition to costly biologic treatments, often leading to lower prices and increased patient access. This creates more treatment options and can reduce the financial burden on the healthcare system and individual patients.
The Active Ingredients: Adalimumab vs. Adalimumab-atto
The active ingredient in Humira is adalimumab. The active ingredient in Amjevita is adalimumab-atto, with the suffix "-atto" used to distinguish it from the reference product and other biosimilars. The manufacturer, Amgen, confirms that Amjevita's active ingredient has the same amino acid sequence as Humira, meaning the core therapeutic component is identical. Both drugs belong to the class of medications known as TNF blockers, which work by targeting and blocking Tumor Necrosis Factor (TNF), a protein that drives inflammation in autoimmune diseases.
Efficacy and Safety: Highly Similar Profiles
Numerous studies and clinical trials have compared Amjevita to Humira, and the overwhelming conclusion is that there are no clinically meaningful differences in efficacy and safety for their approved indications. A 2022 review of 21 studies, for instance, found no difference in safety or effectiveness when switching from Humira to one of its biosimilars. Both medications carry similar risk profiles for side effects, including the risk of serious infections. This high degree of similarity gives both patients and healthcare providers confidence that a biosimilar will produce a comparable therapeutic effect to the reference product.
Approved Indications: Subtle Differences in Scope
For many of the most common conditions they treat, Amjevita and Humira share the same approved indications. However, Humira's extensive history has led to some approved pediatric indications that do not extend to Amjevita. Both are approved for adult conditions such as rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. The key differences in indication scope involve specific pediatric uses:
- Uveitis: Humira is approved for pediatric uveitis (children 2+), while Amjevita is only approved for adult patients.
- Ulcerative Colitis (UC): Humira is approved for pediatric UC (children 5+), whereas Amjevita is only for adults.
- Hidradenitis Suppurativa (HS): Humira is approved for pediatric HS (children 12+), while Amjevita is only approved for adults.
Interchangeability and Prescribing
One of the most important practical differences for patients is the interchangeability status. As of its launch, Amjevita is not designated as an interchangeable biosimilar. This means:
- Prescribing: A doctor must write a specific prescription for Amjevita; a pharmacist cannot automatically substitute it for a prescription written for Humira.
- Pharmacist Substitution: In contrast, an interchangeable biosimilar (like Cyltezo for an older Humira formulation) can be substituted by a pharmacist without requiring prescriber approval, depending on state law.
Cost and Market Impact
Cost is a major factor driving the adoption of biosimilars. Amjevita's manufacturer, Amgen, launched the product with an innovative dual-pricing strategy to increase its accessibility and appeal to different payers. One list price was 55% lower than Humira's, while the other was 5% lower. This strategy, along with competition from other adalimumab biosimilars, has led to a substantial reduction in Humira's net price, significantly changing the market landscape. For patients, this market shift typically translates to lower out-of-pocket costs, though the final price depends heavily on insurance coverage and formulary placement.
Comparison Table: Amjevita vs. Humira
| Feature | Amjevita (adalimumab-atto) | Humira (adalimumab) |
|---|---|---|
| Drug Type | Biosimilar | Reference Biologic |
| Manufacturer | Amgen | AbbVie |
| Active Ingredient | adalimumab-atto | adalimumab |
| FDA Approval | First approved September 2016; launched 2023 | First approved December 2002 |
| Interchangeable | No | N/A (Reference Product) |
| Adult Indications | Largely the same for RA, PsA, AS, CD, UC, PsO | Extensive approval for RA, PsA, AS, CD, UC, PsO, HS, Uveitis |
| Pediatric Indications | More limited, e.g., JIA (children 2+), CD (children 6+) | Broader approval for JIA, CD, UC, HS, Uveitis |
| Relative Cost | Typically less expensive (lower list price options available) | Generally more expensive (higher list price) |
How to Choose: Considerations for Patients and Physicians
Choosing between Amjevita and Humira, or any adalimumab product, should be a decision made in collaboration with a healthcare provider. Key factors to consider include:
- Specific Indication: For pediatric patients with conditions like uveitis or ulcerative colitis, Humira may be the only FDA-approved option.
- Insurance Coverage: An insurance provider may prefer a specific biosimilar, or even the reference product, based on their formulary. Investigating coverage details is crucial for managing costs.
- Cost: For patients with high out-of-pocket expenses, the typically lower cost of biosimilars like Amjevita is a significant advantage.
- Patient Preference: Factors such as the injection device (prefilled syringe vs. autoinjector) or concentration (high vs. low) might influence a patient's preference and adherence.
For more information on biosimilars and their regulatory approval process, visit the FDA's page on the topic: U.S. Food and Drug Administration: Biosimilars.
Conclusion
While Amjevita is a biosimilar and Humira is the reference biologic, they are not meaningfully different in terms of efficacy and safety for their shared approved indications. Both medications contain a version of the active ingredient adalimumab and work by blocking TNF to treat a range of inflammatory diseases. The primary differentiators are Amjevita's non-interchangeable status, the specific pediatric indications for which it is not yet approved, and its typically lower cost. The entry of biosimilars like Amjevita into the market has created more affordable treatment options and increased competition, benefiting the overall healthcare landscape. Ultimately, the choice of medication should be based on a patient's specific needs, in consultation with their healthcare provider.
