What is Tremfya?
Tremfya (guselkumab) is a fully human monoclonal antibody that selectively blocks the p19 subunit of interleukin-23 (IL-23), FDA-approved for treating moderate-to-severe plaque psoriasis, psoriatic arthritis, and ulcerative colitis. 1
Mechanism of Action
Guselkumab works by binding to the p19 subunit of IL-23, preventing IL-23 from interacting with its receptor 1. This disrupts the IL-23/IL-17 inflammatory pathway that drives psoriatic disease 2. By blocking IL-23, guselkumab inhibits the release of proinflammatory cytokines and chemokines, reducing levels of IL-17A, IL-17F, and IL-22 1.
FDA-Approved Indications
Plaque Psoriasis
- Recommended as Grade A monotherapy for moderate-to-severe plaque psoriasis in adults 3
- Effective for scalp, nail, and palmoplantar psoriasis 3
- Superior efficacy compared to adalimumab, with 70% achieving PASI 90 at week 16 versus 46.8% with adalimumab 3
- 66.1% of adalimumab non-responders achieved PASI 90 after switching to guselkumab 3
Psoriatic Arthritis
- Approved for active psoriatic arthritis 4
- Available in both standard (every 8 weeks) and intensified (every 4 weeks) dosing for patients at high risk of joint damage 5
Ulcerative Colitis
- Recently approved for moderate-to-severe ulcerative colitis 6, 7
- Provides clinical remission, endoscopic improvement, and histologic normalization 7
Dosing Regimens
Subcutaneous Administration
- Standard dosing: 100 mg at weeks 0 and 4, then every 8 weeks 3
- Intensified dosing (PsA): 200 mg every 4 weeks for high-risk joint damage patients 5
- Self-administered via prefilled syringe, pen, or One-Press injector 1
Intravenous Administration
- Available as 200 mg IV infusion for ulcerative colitis 1
Clinical Efficacy
Real-world evidence demonstrates:
- PASI 90 response: 50.8% at 12-16 weeks, increasing to 77.1% at ≥96 weeks 8
- PASI 100 response: 49.8% at 20-28 weeks 8
- PsA response: 69.5% achieving DAPSA <14 at 48-60 weeks 8
- Durable responses maintained for up to 2 years 9
Safety Profile
- Generally well tolerated with acceptable safety profile 10
- Common adverse effects: respiratory tract infections, injection site reactions, arthralgia 7
- No definitive evidence of increased malignancy risk, though long-term studies ongoing 3
- Serious adverse events and discontinuations due to adverse events are uncommon 8
Special Populations
Pregnancy: No human pregnancy data available; animal studies at high doses showed no fetal harm but some neonatal deaths at exposures 18-32 times human levels 1
Lactation: Not detected in cynomolgus monkey milk; unknown if present in human milk 1
Pediatrics: Safety and efficacy not established in patients <18 years 1
Geriatrics: No clinically meaningful pharmacokinetic differences based on age 1
Positioning in Treatment Algorithms
Guselkumab represents the first IL-23p19 inhibitor approved for psoriasis 10, 11. It offers advantages of less frequent dosing (every 8-12 weeks) compared to other biologics, which may improve patient preference and adherence 3. The drug has demonstrated efficacy in patients who inadequately responded to ustekinumab, making it a valuable option for biologic-experienced patients 3.