How Siliq Targets Psoriasis
Siliq (brodalumab) treats moderate-to-severe plaque psoriasis by blocking interleukin-17 receptor A (IL-17RA), a key protein that drives inflammation in the skin.[1] Psoriasis occurs when the immune system overproduces inflammatory signals, causing rapid skin cell turnover and thick, scaly plaques. Brodalumab binds to IL-17RA, preventing IL-17 and related cytokines (like IL-17A, IL-17C, IL-17E, and IL-17F) from attaching and triggering this response.[1][2]
Patients typically inject 210 mg subcutaneously once weekly for the first 3 doses (weeks 0, 1, and 2), then every 2 weeks thereafter. Visible improvement often starts within 2-4 weeks, with many achieving clear or nearly clear skin (PASI 90 or better) by week 12 in clinical trials.[1][3]
How It Differs from Other Biologics
Unlike TNF inhibitors (e.g., Humira) or IL-23 blockers (e.g., Tremfya), Siliq acts downstream at the IL-17 receptor, potentially offering faster clearance for tough-to-treat cases. It outperforms IL-17A-specific drugs like Cosentyx by blocking multiple IL-17 family members.[2][4] Head-to-head trials showed higher PASI 100 rates versus ustekinumab (Stelara).[3]
| Drug | Target | Dosing Frequency After Loading |
|------|--------|-------------------------------|
| Siliq | IL-17RA | Every 2 weeks |
| Cosentyx | IL-17A | Every 4 weeks |
| Tremfya | IL-23 | Every 8-12 weeks |
| Skyrizi | IL-23 | Every 12 weeks |
Common Side Effects Patients Report
Most issues are mild: upper respiratory infections (28%), headache (9%), and injection-site reactions (5%). Serious risks include fungal infections (e.g., candidiasis) due to IL-17's role in immunity, and rare suicidal thoughts—patients must enroll in a REMS program with monthly monitoring.[1][5] No increased malignancy risk in trials up to 5 years.[3]
Who Qualifies and When to Expect Results
Approved for adults unresponsive to other systemic therapies or phototherapy. Not for mild psoriasis or those with active infections/Crohn's disease.[1] About 44% reach PASI 90 at week 12, rising to 60% by week 52 with continued use; non-responders can stop early.[3]
Cost and Access Factors
A 4-week supply (4 injections) costs around $5,500-$6,000 without insurance; copay cards often reduce it to $0-$5/month for eligible patients.[6] Covered by most plans for qualifying cases.
Sources
[1]: Siliq Prescribing Information (Bausch Health)
[2]: FDA Approval Summary
[3]: AMAGINE-2/3 Trials (NEJM 2015)
[4]: IL-17 Pathway Review (J Invest Dermatol 2019)
[5]: REMS Program
[6]: Drugs.com Price Guide