Zynlonta is a prescription medicine used to treat adults with certain types of large B-cell lymphoma that has come back (relapsed) or that did not respond to previous treatment (refractory), who have already received two or more treatments for their cancer.

It is not known if this medicine is safe and effective in children.

• Zynlonta is given to you by your healthcare provider as an intravenous (IV) infusion into your vein over 30 minutes.
• Zynlonta is usually given every 3 weeks.
• Your healthcare provider may give you medicine before each infusion to decrease your chance of side effects.
• Your healthcare provider may stop your treatment, delay your treatment, or change your dose if you have severe side effects.
• Your healthcare provider should do blood tests regularly to check for side effects.
• Your healthcare provider will decide how many treatments you need.

Before you start treatment, tell your healthcare provider about all of your medical conditions, including if you:

• have an active infection or have had one recently.
• have liver problems.
• are pregnant or plan to become pregnant. Zynlonta can harm your unborn baby.
  Females who can become pregnant:
  
  • Your healthcare provider may do a pregnancy test before starting treatment.
  • You should use effective birth control (contraception) during treatment, and for 9 months after the last dose. Talk to your healthcare provider about effective birth control. Tell your healthcare provider right away if you become pregnant or think that you are pregnant during treatment.

Males with female partners who can become pregnant:

• • You should use effective birth control (contraception) during treatment, and for 6 months after the last dose.
  • are breastfeeding or plan to breastfeed. It is not known if Zynlonta passes into breast milk. Do not breastfeed during treatment with Zynlonta and for 3 months after the last dose.

Tell your healthcare provider about all the medicines that you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get new medicine.

Avoid or limit your exposure to sunlight, including sunlight through glass, such as buildings or vehicle windows and artificial sunlight such as sunlamps or tanning beds. Exposure to sunlight during treatment can cause skin reaction or rash. Use sun protection measures such as sunscreen and wear loose fitting clothes that cover your skin while out in sunlight.

Zynlonta may cause serious side effects, including:

• Fluid retention. Your body may hold too much fluid during treatment. This can be serious. Tell your healthcare provider if you develop new or worsening swelling or puffiness, weight gain, chest pain, shortness of breath, or trouble breathing.
• Low blood cell counts (platelets, red blood cells, and white blood cells). Low blood cell counts are common with Zynlonta but can also be serious or severe. Your healthcare provider will monitor your blood counts during treatment. Tell your healthcare provider right away if you get a fever of 100.4°F (38°C) or above, or any bruising or bleeding.
• Infections. Serious infections, including infections that can cause death, have happened in people treated with Zynlonta. Tell your healthcare provider right away if you have new or worsening signs or symptoms of infection, including:
  • fever
  • chills
  • flu-like symptoms (cough, tiredness or weakness, and body aches)
  • headache
  • breathing problems
  • cuts or scrapes that are red, warm, swollen or painful
• Skin Reactions. Serious skin reactions have happened in people treated with Zynlonta. Tell your healthcare provider if you get new or worsening skin reactions, including sensitivity to sunlight, skin rash, peeling, redness or irritation. You may burn more easily or get severe sunburns. See What should I avoid while receiving Zynlonta?

The most common side effects include:

• feeling tired or weak
• skin rash
• swelling
• nausea
• muscle or joint pain
• increase in blood sugar (hyperglycemia)
• changes in certain blood or laboratory tests

Zynlonta may cause fertility problems in males which may affect your ability to father children. Talk to your healthcare provider if this is a concern for you. These are not all of the possible side effects. Call your healthcare provider for medical advice about side effects. You may report side effects to FDA at 1 800-FDA-1088.

Other drugs may interact with loncastuximab tesirine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.