Ublituximab-Xiiy

Introduction Overview

Generic Name

ublituximab-xiiy

Brand Name

Briumvi

Dosage Form

injection for intravenous infusion (150 mg/6 mL)

Drug Class

CD20 monoclonal antibodies

Pharmacokinetics

Absorption

Ublituximab-xiiy (Briumvi) is administered via intravenous infusion, thus bypassing the gastrointestinal tract for complete bioavailability. Following IV administration, the drug is immediately available in systemic circulation. Absorption considerations primarily relate to intravenous delivery rate and infusion timing rather than traditional oral absorption mechanisms.

Distribution

Once in systemic circulation, ublituximab-xiiy distributes mainly within the vascular and extracellular spaces. As a monoclonal antibody, it has a volume of distribution approximating plasma and interstitial fluid volumes. Binding is highly specific to CD20-positive B cells, leading to concentration within lymphoid tissues and circulation. The drug does not significantly penetrate the blood-brain barrier; thus, its effects in multiple sclerosis are primarily through peripheral B cell depletion.

Metabolism

Ublituximab-xiiy, like other monoclonal antibodies, undergoes catabolic metabolism primarily by proteolytic enzymes into small peptides and amino acids in cells of the reticuloendothelial system (RES) and other tissues. It is not metabolized via cytochrome P450 enzymes, avoiding hepatic enzyme interactions typical of small molecules. Its clearance can be influenced by CD20 antigen burden and immune complex formation.

Elimination

Elimination of ublituximab-xiiy occurs via nonspecific reticuloendothelial system-mediated catabolism rather than renal or biliary excretion. Clearance kinetics are typical of IgG monoclonal antibodies, with a half-life sufficient for dosing intervals of up to 24 weeks. The exact half-life is variable depending on patient factors but generally ranges between 18 and 25 days. No dose adjustments based on renal or hepatic impairment have been clearly established.

Dosage Forms

Adults

Briumvi is supplied as an injection for intravenous infusion consisting of a single-dose vial containing 150 mg of ublituximab-xiiy in 6 mL solution (25 mg/mL concentration). The recommended dosing regimen for adults with multiple sclerosis includes: an initial infusion of 150 mg over at least 4 hours, a second infusion of 450 mg given two weeks after the first infusion over at least 1 hour, followed by subsequent 450 mg infusions every 24 weeks over at least 1 hour. Premedication with corticosteroids and antihistamines is used to reduce infusion reactions. Monitoring during and post infusion is required.

Adolescents

Briumvi's safety and efficacy in pediatric populations, including adolescents below 18 years of age, have not been established. Therefore, use in adolescents is not recommended outside of clinical trials. No dosing guidelines exist for this population.

Special Populations

In patients with renal or hepatic impairment, pharmacokinetic data are limited due to the monoclonal antibody nature of the drug, with metabolism primarily via proteolytic catabolism rather than organ-based elimination; thus, no dose adjustments are currently recommended. Due to immunosuppressive effects, elderly patients should be monitored carefully for infections and other adverse events. Pregnancy is contraindicated due to potential harm to the fetus, and women are advised to use effective contraception during treatment and for six months after last infusion. Breastfeeding safety is unknown; consult healthcare providers.

Mechanism Of Action

Briumvi (ublituximab-xiiy) is a humanized IgG1 monoclonal antibody that selectively targets CD20, a transmembrane phosphoprotein expressed predominantly on the surface of pre-B and mature B lymphocytes but absent on stem cells and plasma cells. Binding to CD20 facilitates targeted B cell depletion through multiple mechanisms. First, it triggers antibody-dependent cell-mediated cytotoxicity (ADCC) by recruiting natural killer (NK) cells and macrophages to induce apoptosis of CD20-positive B cells. Second, it activates complement-dependent cytotoxicity (CDC), resulting in cell lysis via complement cascade activation. Third, direct induction of programmed cell death signals in B cells may also occur upon antibody binding.

By depleting circulating and tissue-resident B cells, Briumvi alters pathological immune responses associated with multiple sclerosis (MS). B cells contribute to MS pathogenesis through antigen presentation to T cells, secretion of pro-inflammatory cytokines, and production of autoantibodies. Therefore, reducing B cell populations mitigates inflammation and myelin damage in the central nervous system, thereby improving clinical outcomes.

Compared to other anti-CD20 therapies, Briumvi has been engineered for enhanced ADCC activity via glycoengineering of the Fc region, leading to stronger affinity for Fc gamma receptors on effector immune cells. This results in more efficient and rapid depletion of B cells at lower doses or shorter infusion times compared to predecessors like rituximab or ocrelizumab.

Clinical trials demonstrate that Briumvi significantly reduces relapse rates and MRI lesion activity in relapsing MS, indicating potent immunomodulation through B cell targeting. The therapeutic benefits combine with a dosing schedule administered every six months, improving patient compliance and quality of life. Ongoing research focuses on further elucidating B cell subpopulation effects and long-term impact on immune surveillance and infection risk.

Pharmacological Actions

Selective binding to CD20 antigen on B lymphocytes
Induction of antibody-dependent cell-mediated cytotoxicity (ADCC)
Activation of complement-dependent cytotoxicity (CDC) leading to B cell lysis
Direct induction of apoptosis in CD20+ B cells
Depletion of circulating and lymphoid tissue B cells
Reduction of autoimmune-mediated inflammation in the central nervous system
Modulation of pathological immune responses in multiple sclerosis
Suppression of pro-inflammatory cytokine release by B cells
Inhibition of autoreactive B cell antigen presentation to T cells
Reduction in gadolinium-enhancing brain lesions on MRI
Decrease in relapse frequency in multiple sclerosis patients
Prolonged B cell depletion enabling infrequent dosing intervals
Impairment of humoral immune responses leading to immunosuppression

Therapeutic Clinical Uses

Treatment of relapsing forms of multiple sclerosis (MS) in adults
Indicated for clinically isolated syndrome (early MS)
Management of relapsing-remitting multiple sclerosis (RRMS)
Treatment of active secondary progressive multiple sclerosis (SPMS)
Reduction of MS relapse rates compared to teriflunomide
Suppression of new and active brain lesions detected by MRI
Use as an alternative to other anti-CD20 monoclonal antibodies in MS
Immunomodulatory therapy to modify disease course in MS

Side Or Adverse Effects

Infusion reactions including dizziness, nausea, headache, chest tightness, back pain, swelling of face
Herpes virus infections causing cold sores and skin blisters
Upper respiratory tract infections such as common cold symptoms
Peripheral neuropathic pain manifesting as tingling or burning in extremities
Sleep disturbances including insomnia
Fatigue and general tiredness
Risk of serious infections due to immunosuppression
Potential allergic reactions including anaphylaxis
Hepatitis B virus reactivation in patients with prior infection
Possible decrease in blood immunoglobulin levels
Progressive multifocal leukoencephalopathy (PML), a rare brain infection
Flu-like symptoms during or after infusion
Hypersensitivity reactions such as hives and rash
Transient elevated liver enzymes
Leukopenia or reduced white blood cell counts

Precautions

Pre-treatment screening for active infections including hepatitis B virus
Delay treatment in presence of active infection until resolution
Vaccination with all required immunizations prior to initiating therapy
Avoid live or live-attenuated vaccines during and shortly before treatment
Monitor for signs of infusion reactions during and after administration
Cautious use in patients with history of severe infusion-related reactions
Monitor immunoglobulin levels periodically during treatment
Evaluate for neurological symptoms suggestive of PML
Use reliable contraception before, during, and for six months after treatment
Pregnancy testing prior to each infusion
Avoid concomitant use of other immunosuppressive therapies unless necessary
Advise patients on signs and symptoms of infection and when to seek medical care
Close monitoring in elderly or immunocompromised individuals
Proper hydration and steroid premedication to reduce infusion reactions
Assess liver function and monitor for signs of hepatitis B reactivation

Warnings

Risk of serious infusion-related reactions requiring medical intervention
Increased susceptibility to severe infections, including opportunistic infections
Potential reactivation of hepatitis B virus leading to liver failure
Possibility of progressive multifocal leukoencephalopathy (PML), a fatal brain infection
Immune system suppression that may impair response to vaccines
Allergic reactions ranging from mild rash to anaphylaxis
Potential harm to fetus; contraindicated in pregnancy
Unknown long-term immunological effects due to prolonged B cell depletion
Delayed infusion reactions that can occur up to 24 hours post-infusion
Must not be administered concomitantly with live vaccines
Potential decrease in antibody production leading to increased infection risk
Monitoring required for low immunoglobulin levels during therapy
Use caution when combining with other immune suppressants that can exacerbate immunosuppression
Hepatic impairment or failure secondary to viral reactivation or drug toxicity
Possible infusion site reactions including pain and erythema

Contraindications

Known hypersensitivity to ublituximab-xiiy or any component of Briumvi formulation
History of life-threatening allergic reactions to Briumvi or related monoclonal antibodies
Active hepatitis B virus (HBV) infection
Concurrent use of live or live-attenuated vaccines during treatment and until immune recovery
Known severe uncontrolled infections
Pregnancy due to potential fetal harm
Breastfeeding unless risks clearly justified and advised by healthcare provider
Severe immunodeficiency states with high risk of opportunistic infections
Patients unwilling or unable to adhere to contraception requirements
Previous severe infusion-related anaphylactic reactions to ublituximab or similar drugs

Drug Interactions

Concurrent use with other immunosuppressants, including cancer chemotherapy agents, increases infection risk
Steroids and antihistamines used as premedication to mitigate infusion reactions
Avoid live or live-attenuated vaccines during treatment and until immune function is restored
Potential interaction with disease-modifying therapies for multiple sclerosis requiring monitoring
No known cytochrome P450 enzyme interactions due to monoclonal antibody nature
Concomitant use with B cell depleting agents may enhance immunosuppression
No significant interactions with over-the-counter vitamins or herbal products documented but caution advised
Possible interference with immunogenicity of vaccines administered during or after therapy
Potential additive effects on lowering immunoglobulin levels with other biologics
Use caution with medications that affect immune cell function or counts
No clinically significant interaction reported with antihistamines or corticosteroids used as premedication
Concurrent administration with live vaccines contraindicated
Regular monitoring required if combined with other drugs metabolized or cleared by reticuloendothelial system

Preparations Of The Drug

Single-dose vial of Briumvi containing 150 mg of ublituximab-xiiy in 6 mL solution (25 mg/mL) for intravenous infusion
Premedication formulations including corticosteroids (e.g., methylprednisolone) and antihistamines used to reduce infusion reactions
Available only as a sterile injectable solution for IV use; no oral formulations
Supplied with appropriate excipients including hydrochloric acid, polysorbate 80, sodium chloride, sodium citrate, and Water for Injection, USP
No currently available generic or biosimilar versions of Briumvi
Packaging includes instructions for reconstitution and administration by healthcare professionals
Stored under refrigeration as indicated in the prescribing information
Not intended for subcutaneous or intramuscular administration
Manufactured by TG Therapeutics, Inc., for single use only, discard any unused portion
No co-formulated products; administered as separate infusion with supportive care medications