Home Drug Guide Ofatumumab

Drug Guide

Generic Name

Ofatumumab

Brand Names Arzerra, Kesimpta

Classification

Therapeutic: Antineoplastic and immunomodulating agent

Pharmacological: Anti-CD20 monoclonal antibody

FDA Approved Indications

Chronic lymphocytic leukemia (Arzerra)
Multiple sclerosis (Kesimpta)

Mechanism of Action

Ofatumumab binds selectively to the CD20 antigen on B cells, leading to B cell depletion through complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity, and apoptosis.

Dosage and Administration

Adult: For CLL: 300 mg IV initially, then 1,000 mg IV weekly for 4 weeks, then maintenance doses as prescribed. For MS: 20 mg subcutaneously monthly after initial loading dose.

Pediatric: Not approved for pediatric use.

Geriatric: Adjust dose based on tolerability and renal function, with careful monitoring.

Renal Impairment: Adjust dosing as needed, based on renal function.

Hepatic Impairment: No specific adjustments recommended.

Pharmacokinetics

Absorption: Subcutaneous route provides steady absorption; IV provides immediate bioavailability.

Distribution: Wide distribution including lymphoid tissues.

Metabolism: Metabolized via proteolytic degradation into peptides and amino acids.

Excretion: Excreted via proteolytic catabolism.

Half Life: Approximately 24 days.

Contraindications

Active infections
Hypersensitivity to ofatumumab

Precautions

Immunosuppression increasing risk of infections, including hepatitis B reactivation, progressive multifocal leukoencephalopathy (PML), infusion reactions, cardiopulmonary reactions, hypersensitivity reactions, malignancies, and hematologic toxicity.

Adverse Reactions - Common

Injection site reactions (Common)
Upper respiratory infections (Common)
Headache (Common)

Adverse Reactions - Serious

Progressive multifocal leukoencephalopathy (PML) (Rare)
Serious infections (Rare)
Infusion reactions including hypotension, bronchospasm, hypoxia (Potentially serious)

Drug-Drug Interactions

Other immunosuppressants, live vaccines

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Screen for infections, hepatitis B status, and allergies before initiation.

Diagnoses:

Risk for infection
Impaired tissue integrity due to infusion reactions

Implementation: Monitor for infusion reactions, infections, and signs of hypersensitivity during and after administration.

Evaluation: Assess patient’s response, watch for adverse effects, and ensure infection prevention.

Patient/Family Teaching

Report any signs of infection immediately.
Avoid live vaccines during treatment.
Understand possible side effects and when to seek medical help.

Special Considerations

Black Box Warnings:

Progressive multifocal leukoencephalopathy (PML)

Genetic Factors: N/A

Lab Test Interference: May cause false elevation of serum immunoglobulin levels; monitor accordingly.

Overdose Management

Signs/Symptoms: Severe infusion reactions, hypersensitivity, or infection signs.

Treatment: Supportive care, discontinue ofatumumab, and manage symptoms; no specific antidote.

Storage and Handling

Storage: Store vials refrigerated at 2-8°C (36-46°F), protect from light.

Stability: Stable until expiration date when refrigerated.