The International Society on Thrombosis and Haemostasis (ISTH) recently updated their 2020 guideline regarding the management of thrombotic thrombocytopenic purpura due to the emergence of new information regarding immune thrombotic thrombocytopenic purpura (iTTP) and congenital thrombotic thrombocytopenic purpura (cTTP). `

In March of 2024, the ISTH gathered a panel of hematologists, intensivists, nephrologists, pathologists, patient representatives, and a methodology team to appraise evidence and formulate recommendations using the GRADE method. Since the 2020 guideline was published, new and improved tools for diagnosis have emerged, along with a better refined treatment protocols, a stronger understanding of pathophysiology, and advancements of new targeted therapies.

The update panel sorted previously issued recommendations into three groups: recommendations not requiring an update; recommendations requiring incorporation of new evidence, but with no anticipated change in directionality and strength of recommendation; and new recommendations to be issued or previous recommendations requiring assessment, vote, and update considering new evidence.

In total, there was one new recommendation, one updated good practice statement, three recommendations received minimal updates, and another received a notable update.

New in 2025
  • Recommendation 8B: For patients with cTTP who are in remission, the guideline panel recommends recombinantADAMTS-13over plasma infusion to prevent acute episodes. (A strong recommendation in the context of moderate certainty evidence).

The original 2020 guidelines featured good practice statements to accompany the recommendations. Statement 19 was the only statement to receive a notable update in the 2025 guideline update.

  • Good Practice Statement 19: Prophylactic dosing of anticoagulants, most likely low molecular weight heparin, could be considered for patients with iTTP with recovered platelet counts >50 × 109/L, and for those with an increased risk of venous thrombosis (eg, history of recurrent VTE, cancer, and recent surgery). For the optimal management of patients with iTTP and major thrombotic events (eg, stroke, acute myocardial infarction), a multidisciplinary team including hematologists, neurologists, and cardiologists should be consulted.
Updated in 2025

For the following recommendations, new evidence was added, but the strength and direction of the recommendation remains the same:

  • Recommendation 1: For patients with iTTP experiencing a first acute event, the Panel recommends the addition of corticosteroids to TPE over TPE alone. (A strong recommendation in the context of very low certainty evidence). 
  • Recommendation 2: For patients with iTTP experiencing their first acute event, the panel suggests the addition of rituximab to corticosteroids and TPE over corticosteroids and TPE alone. (A conditional recommendation in the context of very low certainty evidence).
  • Recommendation 5: For patients with iTTP experiencing an acute event (first event or relapse), the panel suggests using caplacizumab over not using caplacizumab. (A conditional recommendation in the context of moderate certainty evidence).

Recommendation 7 received a change in direction from neutral to in favor of plasma infusion.

  • Recommendation 7: For patients with cTTP who are in remission, the panel suggests prophylaxis with plasma infusion over a watch-and-wait strategy. (A conditional recommendation in the context of very low certainty evidence).

The full-text version of the guideline update is available online, via the Journal of Thrombosis and Haemostasis.

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