ITP is an autoimmune disorder that can affect both adults and children.^1,2 It is characterised by a severely reduced platelet count and an increased risk of bleeding, which in rare cases may be life-threatening.^2,3 ITP is classified into three phases based on duration: acute (0–3 months), persistent (3–12 months) and chronic (≥12 months).²

Although traditionally considered a disorder of accelerated antibody-mediated platelet destruction, the pathophysiology of ITP also encompasses impaired platelet production.^4,5 Bleeding symptoms may range from common, relatively mild events such as petechiae and bruising to rarer but more serious events such as intracranial haemorrhage.^1,2 The severity of thrombocytopenia imperfectly correlates with bleeding risk; very low platelet counts are permissive but not sufficient to cause bleeding.^1,5

Treatment eligibility for ITP depends not only on platelet count and bleeding tendency but also a multitude of individual patient factors (such as age, comorbidities and related treatments, lifestyle, expectations and tolerance of side effects).² Many adults with ITP do not require treatment unless their platelet count falls below a certain level, they have significant bleeding symptoms or they need to have surgery (for any reason, including dental work).^2,6 Most newly diagnosed children do not require treatment, and the condition resolves within 6–8 weeks.^2,6 However, children with more severe symptoms or an increased risk of bleeding usually need some form of treatment, which tends to be the same as those used in adults.^2,7

First-line treatment for ITP is corticosteroids,^2,7 those with severe bleeding may also receive IV immunoglobulins to accelerate the restoration of platelet counts.^2,5,8 TPO-RAs, such as REVOLADE, are recommended second-line for ITP.^2,7,9 Other treatments that might be used include: romiplostim, rituximab*, avatrombopag^†, azathioprine, ciclosporin A*, cyclophosphamide*, danazole*, dapsone*, fostamatinib^†, mycophenolate mofetil*, and vinca alkaloids*.^2,7 Patients may undergo splenectomy, however, this is only recommended for patients who are refractory to all other treatments and eligibility depends on age and comorbidities .²

*Off-label. ^†Not licensed in the UK.^10,11

Abbreviations: ITP, immune thrombocytopenia; IV, intravenous; TPO-RA, thrombopoietin-receptor agonist.

References

1. Wong RSM, et al. Blood. 2017;130(23):2527–2536.
2. Provan D, et al. Blood Adv. 2019;3(22):3780–3817.
3. Onisai M, et al. Rom J Intern Med. 2019. DOI: 10.2478/rjim-2019-0014. [Epub ahead of print].
4. Ballem PJ, et al. J Clin Invest. 1987;80(1):33–40.
5. Cines DB and Blanchette VS. N Engl J Med. 2002; 346(13):995–1008.
6. Torbay and South Devon NHS Foundation Trust. Patient Information: Immune Thrombocytopenia (ITP). August 2019. Available at: https://www.torbayandsouthdevon.nhs.uk/uploads/23569.pdf (accessed December 2019).
7. NICE. Immune (idiopathic) thrombocytopenic purpura: rituximab. October 2014. Available at: https://www.nice.org.uk/advice/esuom35/chapter/Key-points-from-the-evidence (accessed December 2019).
8. Nomura, S. Clin Med Insights Blood Disord. 2016;6:15–22.
9. REVOLADE Summary of Product Characteristics.
10. NICE. Proposed technology appraisal guidance GID-TA10348. June 2018. Available at: https://www.nice.org.uk/guidance/proposed/gid-ta10348/documents (accessed December 2019).
11. NICE. Proposed technology appraisal guidance GID-TA10387. August 2019. Available at: https://www.nice.org.uk/guidance/proposed/gid-ta10387/documents (accessed December 2019).