It has been ten years since I was first diagnosed with Thrombotic Thrombocytopenic Purpura (TTP). I have learned a lot about TTP over the years plus I have also had the opportunity to make many new friends and support a charity which supports TTP research.
For some background, I have had TTP five times (2012, 2014,
2017, 2019, and 2019). The first incident was the worst. We did not react fast
enough to go to the hospital. Luckily, I was diagnosed quite quickly and
started plasmapheresis. Unfortunately, this was quite late - I had seizures and
was induced into a coma for two days. Through treatments, they found I had an anaphylaxis
reaction to regular plasma transfusion. This is bad when the treatment is to replace
your plasma. Luck was there again as my hematologist ordered solvent/detergent
plasma, even though it was not yet in use in Canada. The good news is that for
subsequent episodes, we recognized the symptoms and thus had more time to get
the tell-tale blood test.
What have we learned over the last ten years?
You don’t find out whether you are going to have TTP by
measuring the platelets. Sure, your platelets are reduced when you have TTP,
but that is a symptom. The cause is, for some reason, the ADAMTS-13 enzyme
activity is reduced, which causes your blood to become sticky with clotting platelets.
Measuring lack of platelets will just tell you that you have TTP. You need to
monitor ADAMTS-13 activity to see if you will get TTP in the future. We never
started monitoring ADAMTS-13 until the end of 2019. Now we monitor monthly.
TTP patients need Rituximab, which is not a
TTP drug. Most governments including the US and Canada do not have rituximab approved
as a TTP drug, it is a cancer drug. However, hematologists have been using rituximab
for many years to help stop the recurrence of TTP. You can see from the USTMA Foundation
treatment protocol that rituximab should be given immediately after plasmapheresis.
For many Canadian patients, rituximab is not easily available until we find out
how it will be paid for. This causes some delays, and I did not receive
Rituximab twice after TTP occurrences. We need to work to make Rituximab
readily available for chronic TTP patients as it can help ADAMTS-13 to return
to normal levels to stop another occurrence of TTP.
A pharmaceutical company has developed a TTP drug called Caplacizumab. This drug
will stop a TTP patient’s platelets from clotting. This gives the TTP patient
time to respond to treatments such as plasmapheresis, corticosteroids, and rituximab.
Caplacizumab is approved for use in the UK and US, but Canadian Agency for
Drugs and Technologies in Health (CADTH) issued a negative recommendation for caplacizumab.
As such, Canada is an outlier and does not support coverage and reimbursement for
this drug. The AnsweringTTP Foundation has taken action to provide advocacy
and awareness to Canada’s provincial health ministers for caplacizumab. Hopefully,
we will have caplacizumab approved for Canadian TTP patients in the future.
So, in the last ten years I have found out what TTP stands
for, what enzyme we need to test, and what drugs we to get. I hope we have even
more progress in the next ten years.
Thanks, Bruce.
@BruceFightsTTP
