Alemtuzumab Injection (Lemtrada) is a CD52-directed cytolytic monoclonal antibody used for the treatment of relapsing multiple sclerosis (MS). Despite its significant efficacy, this medication may cause a range of side effects, some of which can even be life-threatening.

What Are the Side Effects of Alemtuzumab Injection (Lemtrada)?

Common Side Effects

Skin reactions: Rash (53%), pruritus (14%), urticaria (16%).

Systemic symptoms: Fever (29%), fatigue (18%), headache (52%).

Infection-related: Nasopharyngitis (25%), herpes virus infection (16%), urinary tract infection (19%).

Gastrointestinal system: Nausea (21%), diarrhea (12%), vomiting (10%).

Musculoskeletal system: Arthralgia (12%), limb pain (12%), back pain (12%).

Nervous system: Dizziness (10%), paresthesia (10%).

Serious Side Effects Requiring Vigilance for Alemtuzumab Injection (Lemtrada)

Autoimmune Diseases

Mechanism of occurrence: Alemtuzumab can induce the formation of autoantibodies, leading to multi-organ attack.

Immune thrombocytopenia (ITP, 2%): Manifested as abnormal ecchymosis, epistaxis, hematuria; severe cases can cause fatal intracranial hemorrhage. Platelet counts must be monitored monthly until 48 months after the last dose.

Anti-glomerular basement membrane disease (0.3%): Symptoms include edema, hematuria, hemoptysis, which may progress to renal failure. Regular monitoring of serum creatinine and urine routine is required.

Thyroid diseases (36.8%): Including Graves' disease, thyroiditis, etc. TSH levels should be checked every 3 months.

Infusion Reactions

Characteristics: Occur in 92% of patients, with 3% being severe reactions (such as anaphylactic shock, bronchospasm).

Management measures: Pretreatment with glucocorticoids before infusion, and monitoring for at least 2 hours after infusion.

Delayed reactions: Some cases occur more than 24 hours after infusion; patients should be instructed to report symptoms such as chest tightness and rash promptly.

Malignancy Risk

Thyroid cancer (0.3%): Baseline and annual skin examinations are required.

Melanoma: Occurred in 0.3% of patients in clinical trials; annual dermatological evaluation is recommended.

Lymphoproliferative disorders: Including Castleman disease, lymphoma, etc.

Other High-Risk Complications

Stroke and arterial dissection: Mostly occur within 3 days after administration; vigilance is needed for symptoms such as sudden headache and unilateral weakness.

Hemophagocytic lymphohistiocytosis (HLH): Manifested as persistent fever and hepatosplenomegaly, with a high mortality rate.

Acquired hemophilia A: Tendency for spontaneous bleeding; coagulation function should be tested.

Precautions for the Use of Alemtuzumab Injection (Lemtrada)

Pre-Treatment Assessment

Contraindications: Contraindicated in patients with active infection, HIV positivity, or hypersensitivity to alemtuzumab.

Baseline examinations: Include complete blood count, thyroid function, serum creatinine, urine routine, and tuberculosis screening.

Vaccination: Live vaccines must be administered 6 weeks before drug administration.

Monitoring During Treatment

Laboratory follow-up: Monthly complete blood count and renal function tests until 48 months after the last dose; thyroid function tests every 3 months.

Infection prevention:

Herpes virus: Antiviral prophylaxis should be initiated on the day of infusion and continued until CD4+ ≥ 200 cells/μL or for at least 2 months.

Listeria: Avoid raw or undercooked foods; seek medical attention immediately if fever or neck stiffness occurs.