Besponsa is a antineoplastic biological drug used to treat adults with a type of blood cancer called acute lymphoblastic leukemia (ALL), which is also known as acute lymphocytic leukemia.

Besponsa is an antibody-drug conjugate - it uses an antibody to target an anticancer drug to B-cell leukemia cells.

B-cells, which are also known as B-lymphocytes, are part of your immune system and usually help to fight infection. But in people with ALL, the B-cells grow and divide much faster than normal. The abnormal B-cells build up in the bone marrow where they are made, and then spread to the blood and other parts of the body causing ALL. The abnormal B-cells are not fully developed and don't work properly.

Besponsa uses a humanized immunoglobulin class G subtype 4 (IgG4) kappa antibody called inotuzumab to target a cytotoxic drug called calicheamicin to the leukemia cells.

Inotuzumab targets CD22, which is a sialoglycoprotein found on the surface of B-cells. CD22 regulates how B-cells function and proliferate. Inotuzumab delivers the anti-tumor antibiotic calicheamicin to the cancer cells, where it is internalized into the cells. Once inside the cell, calicheamicin is released and works by inducing DNA double strand breaks, which cause the cancer cells to die.

Besponsa was approved by the US Food and Drug Administration in 2017. No biosimilars of Besponsa have been approved. Biosimilars are highly similar versions of the drug that are designed to have the same effect on a person, but they are not identical to the original version of the drug.

What is Besponsa used for?

Besponsa is a prescription medicine used to treat adults with relapsed or refractory B-cell ALL.

It is not known if Besponsa is safe and effective in children under 18 years of age.

Besponsa use is linked to an increased risk of liver problems and death after stem cell transplant.

Besponsa can cause liver problems that can be severe, life-threatening, or fatal, including a condition called veno-occlusive disease (VOD). This condition can occur during treatment with Besponsa or following subsequent treatment with a stem cell transplant. This condition was more common in patients who had elevated liver tests or who received dual alkylating agents in preparation for their stem cell transplant. Patients may be at a higher risk of VOD if they:

• Receive a stem cell transplant after treatment with Besponsa
• Have previously received a stem cell transplant
• Have ongoing or a history of liver problems
• Are of older age
• Received multiple treatments for their ALL prior to Besponsa
• Receive a greater number of Besponsa treatment cycles

Your doctor should perform liver tests periodically during treatment, and may modify or stop your treatment with Besponsa.

Besponsa may cause serious side effects, including:

• Liver problems: Call your doctor right away if you experience rapid weight gain, yellowing of the whites of the eyes, or abdominal swelling that may be painful. The risk of developing VOD is increased after receiving treatment with Besponsa. Discuss with your doctor the benefit/risk of Besponsa treatment if you have a prior history of VOD or serious ongoing liver disease
• Increased risk of death after stem cell transplant: Call your doctor right away if you experience any signs and symptoms of infection or liver problems. There is an increased risk of death due to infection and VOD after receiving Besponsa
• Low blood cell counts: Low blood cell counts and complications of low blood cell counts, including bleeding and infections, which may be severe, life-threatening, and fatal, have occurred with Besponsa. Call your doctor right away if you experience signs and symptoms of infection (for example, redness, swelling), unexpected bleeding or bruising, blood in your urine or stools, or fever
• Infusion-related reactions: Inform your doctor right away if you experience fever, chills, rash, or breathing problems during or following your Besponsa infusion
• Heart problems: Call your doctor right away if you feel dizzy, lightheaded, or faint or have very slow, very fast, or abnormal heartbeats.

• Besponsa will be administered by a healthcare professional in an outpatient setting. Depending on your overall health you may be able to return home after your infusion.
• Besponsa is given by intravenous (IV) infusion into a vein over 1 hour.
• Prior to your infusion, you will be given a steroid, acetaminophen, and an antihistamine to help reduce the chance of infusion reactions.
• After your infusion you will be observed for an hour to watch for infusion reactions
• You may receive only 1 or up to 6 treatment cycles of Besponsa. Your doctor will determine the number of treatment cycles that is right for you. A treatment cycle lasts 21 or 28 days and Besponsa is given on Day 1, Day 8 and Day 15 of each cycle.
• If your doctor plans for you to receive a transplant, you may receive only 2 or 3 treatment cycles of Besponsa.
• If you do not achieve remission by the third cycle, your doctor should stop treating you with Besponsa.

The dosing regimen for the first and subsequent cycles of Besponsa, which depend on the response to treatment, are shown in the table below below.

_{* For patients who achieve a CR or a CRi, and/or to allow for recovery from toxicity, the cycle length may be extended up to 28 days, allowing for a 7-day treatment-free interval starting on Day 21.}

See full prescribing information for further details about Besponsa dosing.

Do not receive Besponsa if you are allergic to inotuzumab ozogamicin or any of the ingredients in it. See below for a complete list of ingredients in Besponsa.

What should I tell my doctor before receiving Besponsa?

Before taking Besponsa, tell your doctor about all of your medical conditions, including if you:

• Have liver disease or a history of liver problems
• Have an infection
• Have ever experienced symptoms such as fever, chills, rash, or breathing problems during or shortly after your Besponsa infusion
• Have heart problems, including an event of QT prolongation

If you miss a scheduled appointment for Besponsa, call you healthcare professional for advice.

Besponsa can cause serious side effects, including:

• See "Important information" above

The most common side effects are:

• low platelet counts (thrombocytopenia)
• low white blood cell counts with and without fever (neutropenia, febrile neutropenia, and leukopenia)
• infection
• low red blood cell counts (anemia)
• fatigue
• bleeding
• fever
• nausea
• headache
• increases in lab tests measuring liver function
• abdomen pain

These are not all of the possible side effects of Besponsa. Tell your doctor if you have any side effect that bothers you or that does not go away. For more information, ask your doctor or pharmacist.

Tell your doctor about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Especially tell your doctor if you take a medication that is known to prolong the QT interval or induce Torsades de Pointes. If you are not sure if you take a medication that can do this then check with your doctor or pharmacist.