Inotuzumab ozogamicin

Inotuzumab ozogamicin is a treatment for some adults with acute lymphoblastic leukaemia (ALL). It is a monoclonal antibody linked to ozogamicin.

Inotuzumab ozogamicin sticks to CD22 proteins on leukaemia cells. CD22 proteins are present in 95% of immature B-ALL cells.

Once in the leukaemia cell, the ozogamicin part of inotuzumab ozogamicin causes severe damage to the DNA, leading to the death of the cell.

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Patients who receive inotuzumab ozogamicin are:

• Adults with CD22-positive relapsed or refractory ALL
• Philadelphia chromosome-positive adults with relapsed or refractory ALL who have had previous unsuccessful treatment with at least one TKI.

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Your haematology team will perform an ECG on you before starting you on inotuzumab ozogamicin. This is important if you are also taking drugs known to prolong QT interval. Your haematology team will check your QT interval on a regular basis.

Inotuzumab ozogamicin can also be dangerous if your levels of immature leukaemia cells are too high. This is because it can be unsafe for you to have too many leukaemia cells dying at the same time. Dead cells release waste products that might overwhelm your kidneys and other organs if they reach high levels in your blood. This is called tumour lysis syndrome.

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You usually have inotuzumab ozogamicin for three or four cycles. You can have up to six cycles if you are not having an allogeneic stem cell transplant (allo-SCT). An allo-SCT is used to make sure you stay in remission if your ALL is considered high-risk.

Usually, inotuzumab ozogamicin is effective after three cycles. If it is not reducing the number of your leukaemia cells, your treatment will be reconsidered. The overall aim of treatment with inotuzumab ozogamicin is to get you back into complete remission.

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Your haematology team will monitor you for at least one hour after the end of your infusion. This is to check for any symptoms of infusion-related reactions. These include:

• Low blood pressure
• Hot flush
• Breathing problems

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There are no formal clinical drug interaction studies with inotuzumab ozogamicin.

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Inotuzumab ozogamicin is still a relatively new treatment, but its effects may be seen over time as it is used more.

Fertility and contraception

Inotuzumab ozogamicin may affect both male and female fertility, but there have not been any studies so far. It is also hard to separate the effects of inotuzumab ozogamicin from other treatments known to affect fertility. For example, you are likely to have already had chemotherapy.

You can seek advice for fertility preservation before treatment. Sometimes your treatment is too urgent to do this.

Pregnancy

Inotuzumab ozogamicin has not been studied in pregnant women. It is not recommended to take inotuzumab ozogamicin during pregnancy.

Breastfeeding

Inotuzumab ozogamicin has not been studied in women who are breastfeeding. But, given its mechanism of action, women should not breastfeed at the following times:

• During treatment with inotuzumab ozogamicin
• For at least two months after the final dose of inotuzumab ozogamicin

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This is not a full list of all the side effects that can happen. The patient information leaflet in your medicine package has more information. Or you can find the leaflet in the Electronic Medicines Compendium.

Below are the most common side effects experienced by patients receiving inotuzumab ozogamicin. The percentages of patients affected by them are also included:

• Low levels of platelets (51% of patients)
• Low levels of neutrophils (49%)
• Infection (48%)
• Low levels of red blood cells (anaemia - 36%)
• Low levels of white blood cells (35%)
• Fatigue (35%)
• Haemorrhage (33%)
• Fever (32%)
• Nausea (31%)

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The most serious side effects with inotuzumab ozogamicin are:

• Infection (23% of patients)
• Febrile neutropenia (11%)
• Haemorrhage (5%)
• Fever (3%)
• Stomach pain (3%)
• Veno-occlusive disease (VOD - 2%)
• Tumour lysis syndrome (2%)

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The aim of inotuzumab ozogamicin is to help you return to remission. If your treatment is successful, your leukaemia blood cell counts will eventually return to within normal ranges.

You might go straight into another treatment even if inotuzumab ozogamicin has worked for you. Your haematology team may use an allogeneic stem cell transplant if you are at high risk of relapse to make sure you stay in remission.

Adding a TKI may improve your complete remission if you are positive for the Philadelphia chromosome. This may improve the chances of remission compared to inotuzumab ozogamicin alone.

If inotuzumab ozogamicin has not worked for you, other treatment options may be available. They include:

• Blinatumomab
• CAR T-cell therapy

Other options include radiation therapy or an allogeneic stem cell transplant. Your consultant will be able to let you know of the best treatment for you going forward.