Lemtrada (Alemtuzumab)

Lemtrada (alemtuzumab) is a humanized monoclonal antibody approved as a disease-modifying therapy for multiple sclerosis. It is administered intravenously and is indicated for patients with relapsing disease activity, offering a targeted approach to reduce relapses and disability progression.

• Relapsing‑remitting multiple sclerosis: in adult patients it significantly lowers the annualized relapse rate, reduces the number of new MRI lesions, and delays the accumulation of disability over time.
• Active secondary progressive multiple sclerosis with relapses: provides disease-modifying benefit by decreasing relapse frequency and may modestly slow the progression of disability in patients who have experienced recent disease activity.

• Alemtuzumab binds with high affinity to the CD52 antigen expressed on the surface of mature T and B lymphocytes. This binding triggers antibody‑dependent cellular cytotoxicity and complement‑mediated lysis, leading to rapid and profound depletion of circulating lymphocytes. The depletion is followed by a gradual repopulation of lymphocyte subsets, which is thought to reset the immune system toward a less autoreactive profile.

Lemtrada may be associated with a range of adverse reactions, varying in frequency and severity.

Common Side Effects

• Infusion‑related reactions: fever, chills, flushing, hypotension, or dyspnea occurring during or shortly after the IV infusion.
• Skin reactions: rash, pruritus, or mild erythema that may appear within days of treatment.
• Gastrointestinal symptoms: nausea, vomiting, or abdominal discomfort.

Serious or Rare Side Effects

• Autoimmune thyroid disease: hyperthyroidism, hypothyroidism, or thyroiditis requiring endocrine monitoring.
• Immune‑mediated cytopenias: thrombocytopenia, neutropenia, or hemolytic anemia that can be severe.
• Serious infections: reactivation of herpes viruses, opportunistic bacterial or fungal infections, and sepsis.

When using Lemtrada, clinicians should observe several precautionary measures to minimize risks and ensure optimal patient outcomes.

• Baseline screening: perform complete blood count, renal function, and thyroid function tests before initiating therapy.
• Infection monitoring: assess for active infections and vaccinate appropriately prior to infusion.
• Autoimmune surveillance: regularly monitor thyroid antibodies and complete blood counts during and after treatment.
• Pregnancy and lactation: avoid use in pregnant or breastfeeding women unless benefits outweigh risks; discuss with specialist.
• Concomitant immunosuppression: limit use of other immunosuppressive agents to reduce infection risk.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake the infusion solution.

Lemtrada can interact with other medicines that affect the immune system or increase infection risk.

Major Interactions (Avoid)

• Live vaccines: administration during or up to 6 months after treatment can cause severe infection.
• Other potent immunosuppressants (e.g., cyclophosphamide, azathioprine): may exacerbate lymphocyte depletion and infection risk.

Moderate Interactions (Monitor Closely)

• Antiviral prophylaxis agents (e.g., acyclovir): may be required to prevent herpes reactivation.
• Hormonal contraceptives: immune modulation may alter efficacy; consider alternative methods.
• Thyroid hormone replacement: dose adjustments may be needed due to autoimmune thyroid changes.
• Inactivated vaccines: may have reduced immunogenicity; assess antibody titers where appropriate.