How do stelara's secondary patents impact biosimilar entry?

Stelara (ustekinumab) is protected by multiple layers of patent coverage—primary (blocking) patents and “secondary” patents (often covering specific formulations, manufacturing, delivery devices, dosing regimens, methods of treatment, or patents that expire later). For biosimilars, those later-expiring (“secondary”) patents can significantly affect when a biosimilar can be launched, even if the original biologic’s main/basic exclusivity has started to fall.

Here’s how secondary patents typically impact biosimilar entry:

1) They can delay launch even after the first “blockers” expire

Biosimilar applicants may be able to show biosimilarity and obtain approval under the abbreviated pathway, but regulatory approval/labeling and marketing can still be constrained by patent litigation and the FDA’s biosimilar patent framework (e.g., litigation stays and “commercial marketing” triggers).
If secondary patents remain in force, the biosimilar sponsor may face a window where:

• the product can be approved, but
• commercial sale is delayed until patent protection clears or a settlement occurs.

2) They raise the risk of “automatic” patent-triggered barriers

In the US framework, sponsors submit patent lists and then litigate. More listed patents = more potential injunction/remaining claims to address. Secondary patents can therefore:

• extend litigation,
• increase the number of matters that must resolve before “at-risk” launch, and/or
• make settlements more likely (or more complex).

3) They may cover non-obvious aspects that are still critical to the biosimilar label

Secondary patents may cover things like:

• specific dosing regimens (e.g., induction/maintenance schedules),
• particular indications (e.g., certain patient populations),
• formulation elements (stabilizers, concentrations),
• manufacturing process steps (which biosimilars must reliably replicate within regulatory similarity),
• device/container-related aspects.

If a secondary patent is tied to an element that must appear in the biosimilar’s prescribing information (or is necessary to compete effectively), it can limit the ability to launch with a commercially useful label.

4) They can constrain “skinny labeling” and launch strategy

While biosimilars sometimes use labeling restrictions (“carve-outs”) to avoid specific patented indications, secondary patents can reduce the ability to do this if they broadly cover multiple aspects of use/dosing.

5) They can affect settlement timing more than approval timing

Approval can occur while lawsuits continue, but secondary patents often control the economics (when the biosimilar can actually be sold). So you’ll often see biosimilar approvals ahead of market entry, with marketing tied to later patent expirations or settlements.

6) International impact (if relevant)

Outside the US, secondary patents can also delay market entry through:

• patent linkage systems (where approval is linked to patent status),
• local enforcement and injunctions,
• different legal standards and timelines.

Important note

Patent landscapes are time-sensitive and jurisdiction-specific. “Secondary patents” doesn’t mean one uniform category—it depends on what patents are listed and asserted in each case.

If you tell me which country/jurisdiction you mean (US FDA pathway vs EU vs UK) and (if US) the biosimilar name(s) you’re focused on, I can summarize the likely mechanisms and what typically happens procedurally with Stelara-related patent thickets there.