The first patient has been dosed at UCLH in a ground breaking trial that could drastically improve the lives of people with a rare blood disorder.
In patients with thrombotic thrombocytopenic purpura (TTP), blood clots form in small blood vessels throughout the body. These clots can limit or block the flow of oxygen-rich blood to the body's organs and result in serious health problems such as strokes or epileptic events. TTP is caused by a lack of activity in the ADAMTS13 enzyme, a type of protein in the blood.
The study will be trialling a new treatment in which patients with congenital TTP (caused by an inherited ADAMTS13 deficiency) will self-inject the enzyme they are missing rather than travelling to hospital for a 90 minute procedure every month. Congenital TTP is very rare, with less than one million of the population estimated to have the condition.
Currently plasma infusion is used to replace ADAMTS 13 in patients with hereditary or congenital TTP. To undergo plasma infusions require patients have to visit a centre every three to four weeks.
Janis Laverack, 66, was diagnosed with TTP in 1968. Every four weeks Janis travels to UCLH for plasma infusion. Janis said: “Once a month I travel to the cancer centre to have three bags of plasma. The process takes an hour and half and each time I spend £30 in a taxi there and back. The process leaves me very tired once I get back home”.
Janis, who has been under the care of Dr Marie Scully for almost 10 years, has suffered three strokes since being diagnosed with TTP and has other medical conditions also. Janis said: “I attend hospital four times a week – to the stroke clinic, pain clinic, osteoporosis clinic and the TTP clinic. To drop one off the list would be really helpful”.
Dr Scully is now leading the new trial where participants will be able to self-medicate by injection using a small butterfly catheter to replace the missing enzyme, without the need for plasma exclusion.
Dr Scully said: “The participants will inject recombinant, specifically engineered protein of the missing enzyme, ADAMTS 13. This type of medication is pure protein for replacement, rather than a blood product. It reduces potential risks and is convenient for patients”.
Another of Dr Scully’s TTP patients, Nicola Barling, 31, travels to UCLH every three weeks on the train from Kent for treatment. Nicola, who suffered a stroke when she was two months pregnant with her son, said: “Following a stroke I have hardly any mobility in my left arm. To be able to self-medicate at home would be really advantageous for me rather than having to come an hour into central London on the train”.
TTP is a relatively new disease with the ADAMTS13 enzyme discovered in 1997. Following the launch of a TTP registry in 2009 more patients have been identified, especially congenital TTP cases and UCLH is the biggest international site for TTP.
