The UK's Medicines and Healthcare products Regulatory Agency (MHRA) has approved Takeda's Adzynma (rADAMTS13) for the treatment of congenital thrombotic thrombocytopenic purpura (cTTP), marking the first therapy authorized in the UK for this ultra-rare blood clotting disorder. The approval, announced on May 12, 2025, applies to patients of all ages.
cTTP is an inherited condition characterized by a deficiency in ADAMTS13, an enzyme critical to normal blood clotting. Patients with the disorder experience blood clots forming in small blood vessels throughout the body, which can block blood and oxygen flow to vital organs. This leads to a variety of severe complications including thrombocytopenia (low platelet count), stroke, and renal and cardiovascular disease.
Breakthrough Enzyme Replacement Therapy
Adzynma functions as an enzyme replacement therapy, providing patients with a purified recombinant form of ADAMTS13 designed to compensate for the deficient enzyme levels. The treatment is administered intravenously.
"A century after the scientific discovery of cTTP, significant unmet needs remain for patients who continue to face life-threatening acute events and debilitating chronic symptoms with limited treatment options," said Ricardo Marek, President of Takeda's Europe and Canada business unit, highlighting the significance of this approval.
Regulatory Pathway and Clinical Evidence
The MHRA's decision utilized the International Recognition Procedure (IRP), a fast-track approval process that considers prior authorizations from trusted regulatory partners. This follows the European Commission's approval of Adzynma in August and the US Food and Drug Administration's authorization in 2023.
The approval was supported by compelling evidence from a phase 3 clinical trial. In this study, cTTP patients were randomized to receive either six months of Adzynma or plasma-based therapies before crossing over to the alternative treatment for another six months. All participants then received Takeda's therapy for months 13 to 18.
Superior Clinical Outcomes
The clinical data demonstrated Adzynma's efficacy and safety profile:
- No patients experienced an acute thrombotic thrombocytopenic purpura (TTP) event while receiving Adzynma as preventative treatment
- In contrast, one acute TTP event occurred in a patient receiving plasma-based therapies
- Only one subacute TTP event was observed in the Adzynma cohort during the first two study periods, compared to seven subacute TTP events in six patients receiving plasma-based therapies
- Efficacy results remained consistent in the continuation period
Monitoring Safety and Effectiveness
As with all medications, the MHRA will maintain close surveillance of Adzynma's safety and effectiveness. Healthcare professionals and patients are encouraged to report any suspected side effects through the MHRA Yellow Card scheme.
The approval represents a significant advancement for patients with cTTP in the UK, who previously had limited treatment options for managing this life-threatening condition. By addressing the underlying enzyme deficiency, Adzynma offers a targeted approach to treating this rare blood disorder.
About Congenital Thrombotic Thrombocytopenic Purpura
cTTP is an ultra-rare inherited blood disorder where blood clots form in small blood vessels throughout the body. The condition is caused by a genetic deficiency in the ADAMTS13 enzyme, which normally helps regulate blood clotting. Without sufficient levels of this enzyme, patients experience microthrombi (tiny blood clots) that can lead to serious complications including organ damage, neurological symptoms, and potentially life-threatening events.
Prior to Adzynma's approval, treatment options for cTTP patients in the UK were limited primarily to plasma-based therapies, which provide temporary supplementation of the missing enzyme but carry risks including allergic reactions and volume overload.
