Tafasitamab – Uses, Dosage, Side Effects, Interactions

Tafasitamab is a humanized, CD19-directed cytolytic monoclonal antibody intended for the treatment of B-cell malignancies.[rx] It is produced using recombinant DNA technology in Chinese hamster ovary cells and contains an IgG1/2 hybrid Fc-domain which has been modified with 2 amino acid substitutions to enhance its cytotoxicity relative to non-engineered anti-CD19 antibodies.[rx],[rx]

The CD19 surface protein is highly expressed on the surface of B-cells, where it appears to play a role in enhancing B-cell receptor signaling.[rx] Its relative ubiquity across different stages of B-cell development, including pre-B and mature B-lymphocytes,[rx], as well as its presence in several B-cell malignancies (e.g. chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), diffuse large B-cell lymphoma (DLBCL))[rx], has made it a desirable target in the treatment these B-cell malignancies. Tafasatimab is designed to bind to and block the activity of the CD19 surface antigen, which ultimately results in the lysis of B-cells (both healthy and malignant).[rx]

Having previously received Breakthrough Therapy, Fast Track, and Orphan designations from the FDA,[rx] tafasatimab-cxix (Monjuvi®) received accelerated approval on July 31st, 2020, for the treatment of relapsed or refractory DLBCL in adult patients who cannot receive autologous stem cell transplants.[rx] It must be used in combination with lenalidomide, as this combination results in greater efficacy as compared to either agent alone.[rx]

Mechanism of action

The CD19 surface antigen is a protein expressed on the surface of pre-B and mature B-lymphocytes[rx] that appears to play a role in enhancing B-cell receptor signaling and is considered integral to their survival.[rx] These surface proteins are also highly expressed in several B-cell malignancies, such as chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), and diffuse large B-cell lymphoma (DLBCL).[rx]

Tafasitamab is a CD19-directed cytolytic monoclonal antibody that, upon binding and blocking the activity of CD19, causes lysis of B-cells. This process is mediated through both direct apoptosis and immune-mediated effector mechanisms, such as antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP).[rx]

Tafasitamab induces a reduction in circulating B-cell counts by binding to a surface antigen, CD19, which is important for their survival.[rx] Patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) experienced a 97% reduction in peripheral blood B-cell counts following 8 days of treatment, with a 100% reduction reached within 16 weeks of treatment.[rx]

Tafasitamab can cause infusion-related reactions, particularly during the initial cycles of therapy. Symptoms may include chills, flushing, dyspnea, and hypertension. Patients may be administered premedications (such as acetaminophen, antihistamines, or glucocorticoids) 0.5 – 2 hours prior to infusion to minimize infusion-related reactions.[rx] Tafasitamab may also cause significant myelosuppression, and subsequent infection, due to its mechanism of action – patients should undergo monitoring throughout therapy for signs of myelosuppression and/or infection.[rx]

Indications

  • Tafasitamab is indicated, in combination with lenalidomide, for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) not otherwise specified who are ineligible for autologous stem cell transplant (ASCT).[rx]
  • Tafasitamab, in combination with lenalidomide, is indicated for the treatment of adults with relapsed or refractory diffuse large B-cell lymphoma (DLBCL).[rx]
  • Tafasitamab is a medication used in combination with lenalidomide for the treatment of adults with relapsed or refractory diffuse large B-cell lymphoma (DLBCL).
  • This drug in combination with lenalidomide, is indicated for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) not otherwise specified, including DLBCL arising from low grade lymphoma, and who are not eligible for autologous stem cell transplant (ASCT)
  • In the EU, injury is indicated in combination with lenalidomide followed by tafasitamab monotherapy for the treatment of adults with relapsed or refractory diffuse large B-cell lymphoma who are not eligible for autologous stem cell transplant.[rx]
  • Refractory Diffuse Large B-Cell Lymphoma, Not Otherwise Specified
  • Relapsed Diffuse large B-cell lymphoma NOS

Use in Cancer

Tafasitamab-cxix is approved to treat:

  • Diffuse large B-cell lymphoma (certain types) that has relapsed (come back) or is refractory (does not respond to treatment). It is used with lenalidomide in adults who cannot receive an autologous stem cell transplant.

This use is approved under FDA’s Accelerated Approval Program. As a condition of approval, a confirmatory trial(s) must show that tafasitamab-cxix provides a clinical benefit in these patients. Tafasitamab-cxix is also being studied in the treatment of other types of cancer.

Contraindications

  • a bad infection
  • anemia
  • decreased blood platelets
  • low levels of a type of white blood cell called neutrophils
  • pregnancy
  • a patient who is producing milk and breastfeeding

Dosage

Strengths: 200 mg

Lymphoma

12 mg/kg IV (based on actual body weight; Administer in combination with lenalidomide 25 mg orally for a maximum of 12 cycles, then continue this drug as monotherapy until disease progression or unacceptable toxicity:

  • CYCLE 1: 12 mg/kg IV on Days 1, 4, 8, 15, and 22
  • CYCLE 2: 12 mg/kg IV on Days 1, 8, 15, and 22
  • CYCLE 3: 12 mg/kg IV on Days 1 and 15
  • NOTE: Each therapy cycle is 28 days.
  • For the first infusion, use an infusion rate of 70 mL/h for the first 30 minutes, then increase the rate so that the infusion is administered within 1.5 to 2.5 hours; administer all subsequent infusions within 1.5 to 2 hours.
  • Refer to the lenalidomide prescribing information for lenalidomide dosage recommendations.
  • Administer premedications 30 minutes to 2 hours prior to starting infusion to minimize infusion-related reactions.
  • Premedications may include acetaminophen, histamine H1 receptor antagonists, histamine H2 receptor antagonists, and/or glucocorticosteroids.
  • For patients not experiencing infusion-related reactions during the first 3 infusions, premedication is optional for subsequent infusions.
  • If a patient experiences an infusion-related reaction, administer premedications before each subsequent infusion.

Dose Adjustments

DOSE MODIFICATIONS FOR ADVERSE REACTIONS:
INFUSION-RELATED REACTIONS (IRRS):

  • GRADE 2: Interrupt therapy and treat the IRR; when resolved to Grade 1, resume infusion at no more than 50% of the rate at which the reaction occurred; if the patient does not experience further reaction within 1 hour and vital signs are stable, the infusion rate may be increased every 30 minutes as tolerated to rate at which the reaction occurred.
  • GRADE 3: Interrupt therapy and treat the IRR; when resolved to Grade 1, resume infusion at no more than 25% of the rate at which the reaction occurred; if the patient does not experience further reaction within 1 hour and vital signs are stable, the infusion rate may be increased every 30 minutes as tolerated to a maximum of 50% of the rate at which the reaction occurred; if after rechallenge the reaction returns, stop the infusion immediately.
  • GRADE 4: Permanently discontinue therapy.

MYELOSUPPRESSION:

  • Platelet counts 50,000/mcL or less: Withhold this drug and lenalidomide and monitor complete blood count (CBC) weekly until the platelet count is 50,000/mcL or higher; resume this drug at the same dose and lenalidomide at a reduced dose (refer to lenalidomide prescribing information for dose modifications).
  • Neutrophil count of 1000/mcL or less for at least 7 days OR neutrophil count of 1000/mcL or less with an increase of body temperature to 100.4F (38C) OR neutrophil count less than 500/mcL: Withhold this drug and lenalidomide and monitor CBC weekly until the neutrophil count is 1000/mcL or higher; ; resume this drug at the same dose and lenalidomide at a reduced dose (refer to lenalidomide prescribing information for dose modifications).

Administration advice:

  • Infuse the entire contents of the bag.
  • Do not coadminister other drugs through the same infusion line.
  • No incompatibilities have been observed between this drug with infusion containers made of polypropylene (PP), polyvinylchloride (PVC), polyethylene (PE), polyethylene terephthalate (PET), or glass and infusion sets made of polyurethane (PUR) or PVC.

Storage requirements:

  • Store unopened product refrigerated at 36F to 46F (2C to 8C) in the original carton to protect it from light. Do not shake. Do not freeze.
  • Use the reconstituted solution immediately.
  • If needed, store the reconstituted solution in the vial for a maximum of 12 hours either refrigerated at 36F to 46F (2C to 8C) or room temperature at 68F to 77F (20C to 25C) before dilution. Protect from light during storage.

Reconstitution/preparation techniques:

  • Reconstitute and dilute this drug prior to infusion.
  • The manufacturer’s product information should be consulted.

Side Effects

The Most Common

  • diarrhea
  • constipation
  • nausea
  • vomiting
  • loss of appetite
  • back pain
  • muscle spasms
  • sore throat, fever, chills, cough, burning or painful urination, or other signs of infection
  • fever or unusual bruising or bleeding
  • pale skin, fatigue, or shortness of breath

Drug Interactions

Pregnancy and Lactation

US FDA pregnancy category: Not assigned.

Pregnancy

Based on its mechanism of action, MONJUVI may cause fetal B-cell depletion when administered to a pregnant woman [see Clinical Pharmacology (12.1)]. There are no available data on MONJUVI use in pregnant women to evaluate for a drug-associated risk. Animal reproductive toxicity studies have not been conducted with tafasitamab-cxix. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. MONJUVI is administered in combination with lenalidomide for up to 12 cycles. Lenalidomide can cause embryo-fetal harm and is contraindicated for use in pregnancy. Refer to the lenalidomide prescribing information for additional information. Lenalidomide is only available through a REMS
program.

Lactation

There are no data on the presence of tafasitamab-cxix in human milk or the effects on the breastfed child or milk production. Maternal immunoglobulin G is known to be present in human milk. The effects of local gastrointestinal exposure and limited systemic exposure in the breastfed infant to MONJUVI are unknown. Because of the potential for serious adverse reactions in the breastfed child, advise women not
to breastfeed during treatment with MONJUVI and for at least 3 months after the last dose. Refer to lenalidomide prescribing information for additional information.

Why is this medication prescribed?

Tafasitamab-cxix injection is used in adults along with lenalidomide (Revlimid) to treat certain types of non-Hodgkin’s lymphoma (types of cancer that begin in a type of white blood cells that normally fights infection) that have returned or that did not respond to other treatments in those who cannot receive a stem cell transplant. Tafasitamab-cxix injection is in a class of medications called monoclonal antibodies. It works by helping the body to slow or stop the growth of cancer cells.

How should this medicine be used?

Tafasitamab-cxix comes as a powder to be mixed with a liquid and given into a vein by a doctor or nurse in a healthcare setting. Tafasitamab-cxix is usually given on days 1, 4, 8, 15, and 22 of cycle 1, on days 1, 8, 15 and 22 on cycles 2 and 3, and on days 1 and 15 of cycles 4 to 12. Each treatment cycle is 28 days and tafasitamab-cxix is given for up to 12 cycles. The length of treatment depends on how well your body responds to the medication and any side effects you experience.

Tafasitamab-cxix may cause serious reactions while you receive the medication. You may be given other medications to treat or help prevent reactions to tafasitamab-cxix. A doctor or nurse will watch you closely while you are receiving the infusion to be sure you are not having a serious reaction to the medication. Tell your doctor or nurse immediately if you experience any of the following symptoms: chills, flushing, headache, or shortness of breath.

Your doctor may temporarily or permanently stop your treatment if you experience certain side effects. Be sure to tell your doctor how you are feeling during your treatment with tafasitamab-cxix.

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before receiving tafasitamab-cxix,

  • tell your doctor and pharmacist if you are allergic to tafasitamab-cxix, any other medications, or any of the ingredients in tafasitamab-cxix injection. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have an infection or if you have or have ever had an infection that keeps coming back.
  • tell your doctor if you are pregnant or plan to become pregnant. You should use birth control to prevent pregnancy during your treatment with tafasitamab-cxix and for at least 3 months after your final dose. Talk to your doctor about types of birth control that will work for you. If you become pregnant while receiving tafasitamab-cxix injection, call your doctor.
  • tell your doctor if you are breastfeeding. Do not breastfeed during your treatment with tafasitamab-cxix and for 3 months after your final dose.

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