1. Clinical Overview
Itolizumab is a recombinant humanized monoclonal antibody of the IgG1 isotype, specifically targeting the CD6 receptor on T-cells. It is a first-in-class biologic therapy developed in India for the management of moderate to severe chronic plaque psoriasis. It works by modulating T-cell activation and proliferation, thereby reducing the inflammatory cascade responsible for psoriatic lesions. It is administered as an intravenous infusion.
| Onset | Duration | Bioavailability |
|---|---|---|
| Clinical improvement in Psoriasis Area and Severity Index (PASI) score is typically observed within 4-6 weeks of initiating therapy. | The pharmacodynamic effect persists for several weeks post-infusion, with a dosing interval of every 2 weeks during the induction phase and every 4 weeks for maintenance. | 100% via intravenous administration. |
2. Mechanism of Action
Itolizumab binds to the CD6 receptor, a co-stimulatory molecule predominantly expressed on mature T-lymphocytes and a subset of B-cells (B1 cells). This binding modulates the CD6-CD166/ALCAM (Activated Leukocyte Cell Adhesion Molecule) interaction pathway, which is crucial for T-cell activation, proliferation, differentiation, and migration to sites of inflammation.
3. Indications & Uses
- Moderate to Severe Chronic Plaque Psoriasis in adult patients who are candidates for systemic therapy
- Moderate to Severe Psoriasis in adult patients who have failed topical therapy and phototherapy
4. Dosage & Administration
Adult Dosage: Induction: 1.6 mg/kg body weight administered as an intravenous infusion every 2 weeks for the first 12 weeks (total 7 doses). Maintenance: 1.6 mg/kg every 4 weeks thereafter. The 25mg vial is used as part of the calculated total dose.
Administration: For intravenous infusion only. Must be reconstituted with 5 mL of Water for Injection. Further dilute in 100 mL of 0.9% Sodium Chloride Injection. Administer over a 2-hour period using an infusion set with a 0.2 micron in-line filter. Pre-medicate with an antihistamine (e.g., Hydroxyzine 25mg) and corticosteroid (e.g., Dexamethasone 8mg IV) 30 minutes prior to infusion to minimize reactions.
5. Side Effects
Common side effects may include:
- Infusion-related reactions (pyrexia, chills, headache, nausea)
- Upper respiratory tract infections
- Fatigue
- Pruritus
- Increased liver enzymes (AST/ALT)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other Biologic DMARDs (e.g., Adalimumab, Etanercept, Infliximab) | Increased risk of serious infections and immunosuppression | Major |
| Live Vaccines (e.g., MMR, Varicella, Yellow Fever) | Risk of disseminated vaccine-induced infection | Major |
| CYP450 Substrates (Warfarin, Cyclosporine) | Unlikely interaction as Itolizumab is not metabolized by CYP450 | None |
| Systemic Corticosteroids | Additive immunosuppression, increasing infection risk | Moderate |
7. Patient Counselling
- Do report any signs of infection (fever, cough, sore throat) immediately.
- Do complete all recommended vaccinations (non-live) before starting therapy.
- Do attend all scheduled infusion appointments.
- Don't receive any live vaccines while on Itolizumab.
- Don't self-medicate for fever or infections; consult your doctor.
8. Toxicology & Storage
Overdose: No cases of overdose reported in clinical trials. Theoretical risks include severe immunosuppression leading to opportunistic infections and exacerbated cytokine release syndrome manifesting as high fever, rigors, hypotension, and tachycardia.
Storage: Store unopened vials at 2°C to 8°C in a refrigerator. Do not freeze. Protect from light. Keep in outer carton. The reconstituted and diluted solution should be used immediately. If not used immediately, the chemical and physical stability of the diluted solution has been demonstrated for up to 24 hours at 2°C to 8°C, followed by 4 hours at room temperature (not exceeding 30°C). Do not store partially used vials.