Haematology

 

What is TTP Relapse?

This is when your platelet count is normal, but your ADAMTS13 activity level has fallen below the normal range. Additionally, you may or may not have symptoms.

Treatments is needed to prevent a full clinical relapse if you have either:

  • A persistent ADAMTS13 activity level of less than 20
  • Previously had a normal ADAMTS13 activity level and now it is below the normal range, and you are symptomatic

Why have I been prescribed Obinutuzumab?

You have been prescribed Obinutuzumab for the following reasons

  • You have had an ADAMTS13 relapse less than 12 months after previously being treated with Rituximab for an ADAMTS13 relapse.
  • You are intolerant of Rituximab. This means you either had a severe allergic reaction to Rituximab, developed infusion related reactions to Rituximab induced serum sickness, (a rash, joint pain, or stiffness, facial or limb swelling or fever).

Obinutuzumab is licensed for several other haematological conditions. NHS England have reviewed the evidence to electively prevent TTP relapse for patients who relapsed within 12 months after being treated with Rituximab or developed a reaction to Rituximab with Obinutuzumab.

Consent

Your doctor will talk to you about the benefits and possible side effects of treatment with Obinutuzumab as treatment for your ADAMTS13 relapse, and help you decide if this is the right treatment for you. The team will ask you to sign a consent form prior to starting treatment.

How does it work?

Obinutuzumab reduces activity of your immune system. Obinutuzumab is a monoclonal antibody, a type of protein that sticks to the surface of a white blood cell called a B Cell. When Obinutuzumab sticks to the surface of the B cell, the cell dies, Therefore, significantly reducing the number of antibodies your body is producing.  

It can take several weeks before it starts to take effect. If you respond well to Obinutuzumab, you will probably feel better within a four-to-six-week period.

How is Obinutuzumab given?

Obinutuzumab is given as an infusion through a cannula (a tube into a vein in your arm) weekly for three weeks. (three x 1000mg doses) you will be given premedication 30 minutes before the start of your infusions to reduce the risk of you developing any reactions side effects.

Week one is split into two consecutive days, as a small test dose of 100mg, this will be given initially on day one followed by the rest of the dose 900mg the next day two.

It can take four to six hours to administer for each dose to be given. The first dose is often at a slower rate with close monitoring so that any infusion related reactions or side effects can be treated early.

The team in day ward will take weekly blood samples prior to each weekly dose and once you have completed the initial treatment you will be monitored in clinic.

What are the risks of Obinutuzumab

Most people who are treated with Obinutuzumab for an ADAMTS13 relapse have few side effects, you may get some of these listed below but are very unlikely to get all of them.

Side Effects while Obinutuzumab is being given

Allergic Reaction

Most common reactions can happen during the first infusion, you will be given drugs before the infusion to reduce the risk of allergic reaction. Allergic reactions are usually mild,  but rarely can be severe.

If you have an allergic reaction, the nurse will usually treat this by slowing down the infusion or stopping the drip. You may require additional treatment such as an antihistamine or paracetamol. When the symptoms improve, the rest of the Obinutuzumab will be given at a slower rate to minimize the risk of any further reaction. These reactions are less likely to happen after the second Infusion. If your reaction is severe, the Obinutuzumab will be stopped, and your doctor will be informed.

The nurse will check for signs of an allergic reaction, but always tell your nurse or doctor immediately if you have any of the following symptoms:

  • A rash or feel itchy,
  • Breathless, cough, or wheezy.
  • Felling nauseous
  • Flu like symptoms
  • Pain in your back or stomach or chest
  • Changes in Blood Pressure

Your Blood Pressure may fall whilst having Obinutuzumab.

If you usually take medication to lower your blood pressure, your doctor may ask you not to take it 12 hours before having Obinutuzumab.

Common Side Effects

  • Risk of infection
  • Brusing and bleeding
  • Anaemia (low number of red blood cells)
  • Feeling tired
  • Headaches
  • Diarrhoea and constipation
  • Problems passing urine
  • Your hair may get thinner
  • Skin changes
  • Muscle and joint pain
  • Difficulty sleeping or mood change
  • Effects on your Lungs
  • Heart problems

Rare Side Effects of Obinutuzumab

  • Effects on the nervous system This is a very rare side effect on the nervous system, but it can cause a condition called PML (Progressive multifocal leukoencephalopathy), this is a very rare brain infection.
  • Stomach pain
  • Skin Cancer

Obinutuzumab can increase the risk of developing types of skin cancer

  • Hepatitis B reactivation

What should I do if I have any side effects?

Of you experience any side effects during the infusion, immediately tell your nurse or doctor. If you experience any side effects after you have left the hospital, contact the Haematology team on 0151 706 3397.

Starting any new Medications

Before you start any new medications, you must check with your doctor or pharmacist to ensure they do not react with Obinutuzumab.

Vaccinations:

Tell your doctor prior to starting treatment if you think you need any vaccinations including flu, pneumonia or covid.

Pregnancy and Contraception

You must tell your nurse or Doctor if you are pregnant, think you might be pregnant

Or are planning to become pregnant.

It is important to use effective contraception during treatment with Obinutuzumab and for 18 months after treatment has been stopped.

Please see information below to contact the team

Feedback

Your feedback is important to us and helps us influence care in the future.

Following your discharge from hospital or attendance at your outpatient appointment you will receive a text asking if you would recommend our service to others. Please take the time to text back, you will not be charged for the text and can opt out at any point. Your co-operation is greatly appreciated.

 

Further information

Contact the Haematology Team on 0151 706 3397

Text phone number:  18001 0151 706 3397

or out of hours via switchboard call 0151 706 2000 and ask

for the Haematology Registrar on call.

 

Author: Clinical Haematology - TTP Nursing Team.

Review date: May 2029

PI 3240 V1