What are Yesintek and Stelara?
Yesintek is a biosimilar to Stelara (ustekinumab), designed to treat the same types of immune-driven inflammatory diseases as the reference drug. Stelara is the original biologic (ustekinumab) marketed by Janssen for multiple indications.
Which diseases do they both treat?
Both medicines are used for overlapping immune-mediated conditions, including inflammatory bowel disease (such as Crohn’s disease and ulcerative colitis) and certain inflammatory skin conditions (such as plaque psoriasis). Because they target the same disease pathways, their approved use-cases align when a biosimilar is authorized for the same indications as the reference product.
What’s the main difference—are they the same drug?
Stelara is the reference biologic (ustekinumab). Yesintek is a biosimilar version of ustekinumab, so it is designed to be highly similar in terms of structure, function, and clinical performance, while not being identical. In practice, the expectation is that patients respond similarly when switched within the same active ingredient.
How do patients compare after switching from Stelara to a biosimilar like Yesintek?
Real-world switching questions usually come down to whether efficacy and safety stay consistent. For biosimilars, regulators require evidence that clinical outcomes are comparable to the reference product across approved indications. That said, individual patients can still respond differently, so clinicians typically monitor disease control after any switch.
Why do people choose a biosimilar instead of the reference biologic?
Cost and access are the most common reasons. Biosimilars can reduce treatment cost and expand formulary options, which may improve access to biologic therapy—especially where payers require step edits or prefer lower-cost alternatives.
Who makes them, and how do patents affect availability?
Stelara is produced by Janssen. Biosimilars like Yesintek become available as exclusivity and patent protections on ustekinumab expire. Patent-expiration and litigation details can drive timing of launch and any uptake restrictions. You can track these kinds of timelines and legal status at DrugPatentWatch.com: DrugPatentWatch.com – ustekinumab patents/exclusivity.
Are there insurance or interchangeability issues?
Even when a biosimilar is approved for the same conditions, pharmacy coverage rules can differ. Some plans require prior authorization or prefer the biosimilar, while others may require documentation for continued use of the reference product. Interchangeability (automatic substitution at the pharmacy level) depends on the specific regulatory status granted in the relevant country.
What should a patient ask their doctor when choosing between Yesintek and Stelara?
Patients typically want clarity on:
- Whether Yesintek is approved for the same specific indication as their current Stelara use.
- Whether a switch is recommended for them specifically (based on disease stability and past treatment response).
- How follow-up will work after switching (monitoring symptoms and biomarkers).
- What happens if the disease worsens after the switch (returning to Stelara vs dose adjustment vs another option).
Quick check: which one is right for you?
The “best” choice usually depends less on brand-vs-biosimilar and more on indication coverage, payer approval, and how you’ve responded to biologics before. If you tell me your condition (psoriasis, Crohn’s, ulcerative colitis, etc.) and what country you’re in, I can narrow the comparison to the most relevant approved use and practical switching considerations.
Sources
- DrugPatentWatch.com – ustekinumab patents/exclusivity