Ublituximab

12.1 Mechanism of Action The precise mechanism by which ublituximab-xiiy exerts its therapeutic effects in multiple sclerosis is unknown, but is presumed to involve binding to CD20, a cell surface antigen present on pre-B and mature B lymphocytes. Following cell surface binding to B lymphocytes, ublituximab-xiiy results in cell lysis through mechanisms including antibody-dependent cellular cytolysis and complement-dependent cytolysis.

1 INDICATIONS AND USAGE BRIUMVI is indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults. BRIUMVI is a CD20-directed cytolytic antibody indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults ( 1 , 14 ).

2 DOSAGE AND ADMINISTRATION Before initiating BRIUMVI, screen for Hepatitis B virus (HBV) and obtain serum quantitative immunoglobulins, aminotransferases, alkaline phosphatase, and bilirubin ( 2.1 ). Pre-medicate with methylprednisolone (or an equivalent corticosteroid) and an antihistamine (e.g., diphenhydramine) prior to each infusion ( 2.2 ). Administer BRIUMVI by intravenous infusion. First Infusion: 150 mg intravenous infusion ( 2.3 ) Second Infusion: 450 mg intravenous infusion two weeks after the first infusion ( 2.3 ) Subsequent Infusions: 450 mg intravenous infusion 24 weeks after the first infusion and every 24 weeks thereafter ( 2.3 ) Must be diluted in 0.9% Sodium Chloride Injection, USP prior to administration ( 2.3 , 2.6 ). Monitor patients closely during and for at least one hour after the completion of the first two infusions. Post-infusion monitoring of subsequent infusions is at physician discretion unless infusion reaction and/or hypersensitivity has been observed ( 2.3 , 5.1 ). 2.1 Assessments Prior to First Dose of BRIUMVI Hepatitis B Virus Screening Prior to initiating BRIUMVI, perform Hepatitis B virus (HBV) screening. BRIUMVI is contraindicated in patients with active HBV confirmed by positive results for Hepatitis B surface antigen [HBsAg] and anti-HBV tests. For patients who are negative for HBsAg and positive for Hepatitis B core antibody [HBcAb+] or are carriers of HBV [HBsAg+], consult liver disease experts before starting and during treatment with BRIUMVI [see Warnings and Precautions (5.2) ] . Serum Immunoglobulins Prior to initiating BRIUMVI, perform testing for quantitative serum immunoglobulins [see Warnings and Precautions (5.4) ]. For patients with low serum immunoglobulins, consult immunology experts before initiating treatment with BRIUMVI. Vaccinations Because vaccination with live-attenuated or live vaccines is not recommended during treatment and after discontinuation until B-cell repletion, administer all immunizations according to immunization guidelines at least 4 weeks prior to initiation of BRIUMVI for live or live-attenuated vaccines and, whenever possible, at least 2 weeks prior to initiation of BRIUMVI for non-live vaccines [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.2) ] . Liver Function Tests Prior to initiating BRIUMVI, obtain serum aminotransferases (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]), alkaline phosphatase, and bilirubin levels [see Warnings and Precautions (5.5) ] . 2.2 Assessment and Premedication Before Every Infusion Infection Assessment Prior to every infusion of BRIUMVI, determine whether there is an active infection. In case of active infection, delay infusion of BRIUMVI until the infection resolves [see Warnings and Precautions (5.2) ] . Recommended Premedication Pre-medicate with 100 mg of methylprednisolone administered intravenously (or an equivalent oral dosage or equivalent corticosteroid) approximately 30 minutes prior to each BRIUMVI infusion to reduce the frequency and severity of infusion reactions [see Warnings and Precautions (5.1) ] . Pre-medicate with an antihistamine (e.g., diphenhydramine) administered orally or intravenously approximately 30-60 minutes prior to each BRIUMVI infusion to further reduce the frequency and severity of infusion reactions. The addition of an antipyretic (e.g., acetaminophen) may also be considered. 2.3 Recommended Dosage and Dose Administration Administer BRIUMVI under the close supervision of an experienced healthcare professional with access to appropriate medical support to manage severe reactions, such as serious infusion reactions. First Infusion: 150 mg intravenous infusion Second Infusion: 450 mg intravenous infusion administered two weeks after the first infusion Subsequent Infusions: 450 mg intravenous infusion administered 24 weeks after the first infusion and every 24 weeks thereafter Observe the patient for at least one hour after the completion of the first two infusions. Post-infusion monitoring of subsequent infusions is at physician discretion unless infusion reaction and/or hypersensitivity has been observed in association with the current or any prior infusion [see Warnings and Precautions (5.1) ]. Table 1: Recommended Dose, Infusion Rate, and Infusion Duration for MS Dose (mg) and Volume (mL) of BRIUMVI Volume (mL) of 0.9% Sodium Chloride Injection, USP Withdraw and discard the required volume of 0.9% Sodium Chloride Injection, USP from the infusion bag following the preparation instructions in Preparation and Administration (2.6). Infusion Rate (mL/hour) Duration Infusion duration may take longer if the infusion is interrupted or slowed. First Infusion 150 mg (6 mL) 250 mL Start at 10 mL per hour for the first 30 minutes Increase to 20 mL per hour for the next 30 minutes Increase to 35 mL per hour for the next hour Increase to 100 mL per hour for the remaining 2 hours 4 hours Second Infusion (2 weeks later) 450 mg (18 mL) 250 mL

6 ADVERSE REACTIONS The following serious adverse reactions are discussed in greater detail in other sections of the labeling: Infusion Reactions [see Warnings and Precautions (5.1) ] Infections [see Warnings and Precautions (5.2) ] Reduction in Immunoglobulins [see Warnings and Precautions (5.4) ] Liver Injury [see Warnings and Precautions (5.5) ] The most common adverse reactions (≥10%) were infusion reactions and upper respiratory tract infections ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact TG Therapeutics at 1-877-848-9462 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. In active-controlled clinical trials (Study 1 and Study 2), 545 patients with RMS received BRIUMVI [see Clinical Studies (14) ]. The most common adverse reactions in RMS trials (incidence of at least 10%) were infusion reactions and upper respiratory tract infections. Table 2 summarizes the adverse reactions that occurred in RMS trials (Study 1 and Study 2). The most common cause of discontinuation in patients treated with BRIUMVI was infection (1.3%). Table 2: Adverse Reactions in Adult Patients with RMS with an Incidence of at least 5% for BRIUMVI and Higher than Teriflunomide from Study 1 and Study 2 BRIUMVI 450 mg IV The first dose of BRIUMVI was given as an intravenous (IV) infusion of 150 mg. The second dose was given as an IV infusion of 450 mg two weeks after the first infusion. Teriflunomide 14 mg PO Adverse Reactions (N=545) % (N=548) % Infusion reactions 48 12 Upper respiratory tract infections Includes the following: nasopharyngitis, upper respiratory tract infection, respiratory tract infection, respiratory tract infection viral, pharyngitis, rhinitis, sinusitis, acute sinusitis, tonsillitis, laryngitis, chronic sinusitis, viral pharyngitis, viral rhinitis, viral upper respiratory tract infection, chronic tonsillitis, pharyngitis streptococcal, sinusitis bacterial, and tonsillitis bacterial. 45 41 Lower respiratory tract infections Includes the following: bronchitis, pneumonia, tracheitis, tracheobronchitis, COVID-19 pneumonia, bronchitis bacterial, and pneumonia viral. 9 7 Herpes virus-associated infections Includes several related terms. 6 5 Pain in extremity 6 4 Insomnia 6 3 Fatigue 5 4 Infusion Reactions The incidence of infusion reactions was highest with the first infusion (43%), decreasing with subsequent infusions (10% with second, 8% with third infusion). Three (0.6%) patients treated with BRIUMVI reported serious infusion reactions. Most frequently reported symptoms (greater than 5%) included pyrexia, chills, headache, and influenza-like illness [see Warnings and Precautions (5.1) ] . Laboratory Abnormalities Decreased Immunoglobulins BRIUMVI decreased total immunoglobulins with the greatest decline seen in IgM levels. The proportion of BRIUMVI-treated patients at baseline reporting IgG, IgA, and IgM below the LLN was 6.3%, 0.6%, and 1.1%, respectively. Following treatment, the proportion of BRIUMVI-treated patients reporting IgG, IgA, and IgM below the LLN at 96 weeks was 6.5%, 2.4%, and 20.9%, respectively. Decreased Neutrophil Levels In Studies 1 and 2, decreased neutrophil counts (<LLN) occurred in 15% of BRIUMVI-treated patients compared to 22% in teriflunomide-treated patients. The majority of decreased neutrophil counts were observed once for a given patient treated with BRIUMVI, and were between 1.0 and 1.5 × 10 9 /L. In RMS studies, 3% of patients in the BRIUMVI group had neutrophil counts less than 1.0 × 10 9 /L, compared to 2% of patients in the teriflunomide group. Overall, 1% of patients in the BRIUMVI group had neutrophil counts less than 0.5 × 10 9 /L, compared to 0% of patients in the teriflunomide group, and these were not associated with an infection. 6.2 Postmarketing Experience The following adverse reactions have been identified during postapproval use of BRIUMVI. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Hepatobiliary Disorders: Liver injury [see Warnings and Precautions (5.5) ] Infections and Infestations: Progressive multifocal leukoencephalopathy [see Warnings and Precautions (5.2) ]

7 DRUG INTERACTIONS 7.1 Immunosuppressive or Immune-Modulating Therapies The concomitant usage of BRIUMVI with other immune-modulating or immunosuppressant drugs, including immunosuppressant doses of corticosteroids, may increase the risk of infection. Consider the risk of additive immune system effects when co-administering immunosuppressive therapies with BRIUMVI. When switching from therapies with immune effects, the duration and mechanism of action of these therapies should be taken into account because of potential additive immunosuppressive effects when initiating BRIUMVI.