Abstract
Introduction Primary immune thrombocytopenia (ITP) is a rare autoimmune bleeding disorder characterized by increased platelet destruction with or without impaired platelet production, resulting in markedly low platelet counts, and consequent bleeding risk. ITP is defined as persistent in the 3–12 months from diagnosis, and chronic if it continues for >12 months from diagnosis.Mucocutaneous bleeding is the most common bleeding symptom, and severe gastrointestinal, intracranial, or urinary tract bleeds can be life-threatening. Standard first-line treatment consists of corticosteroids. Subsequent therapies can include thrombopoietin receptor agonists (TPO-RAs), fostamatinib, rituximab, immunosuppressants, and other medications, as well as splenectomy. Intravenous (IV) immunoglobulin (IG) and anti-D IG can be given to control an ongoing bleed. Despite existing therapies, there is still an unmet need in primary ITP management. The objective of this analysis was to understand the clinical characteristics, treatment patterns, and bleeding events among adult patients with previously treated primary ITP in the US.Methods A retrospective cohort study was conducted using data from an administrative claims database in the US (HealthVerity) on adults with ITP who were prescribed ITP treatment between October 2015 and May 2022. Inclusion criteria were: at least one ITP inpatient or at least two ITP outpatient diagnosis codes (ICD-10-CM code D69.3). Patients with an ITP diagnosis code in the 6 months prior to the index date, a secondary cause of thrombocytopenia, or patients under 18 years old were excluded. Following the initial ITP diagnosis, previously treated patients were identified as those who were currently on ITP treatment and who had received one prior therapy comprising an oral corticosteroid, IVIG, IV anti-D, or platelet transfusion, as well as one or more prior therapies comprising TPO-RA, rituximab, fostamatinib, anti-CD-38 monoclonal antibodies, immunosuppressants, danazol, dapsone, bortezomib, vinca alkaloid, or splenectomy. Index date was the date of initiation of the next ITP regimen after meeting the previously treated definition. Patients were followed until the end of study period (May 31, 2022) or end of patient enrollment, whichever occurred first. ITP treatment, use of rescue therapies, and bleeding events were assessed. Bleeding events were identified based on diagnosis codes and classified as major, moderate, or minor, for those requiring a hospitalization, emergency room visit, or outpatient visit alone, respectively.Results For the 34 patients with previously treated primary ITP, the median follow-up duration was 16.3 months after index date. The median age at index date was 49.5 (range: 22.0 to 75.0) years old; 71% were female. At the index date, 47% were classified as having persistent ITP, 44% as chronic ITP, and 9% were newly diagnosed. The median duration from ITP diagnosis to index date was 10.1 (range: 2.6 to 57.5) months. Before the index date, all patients received oral steroids; 35% and 38% of patients received TPO-RA(s) and rituximab, respectively; 29% received immunosuppressants; and 3% had a splenectomy. In the regimen initiated at the index date, 47% of patients received TPO-RA-containing regimens (21% TPO-RA monotherapy and 27% TPO-RA combination therapy), 35% received oral corticosteroid monotherapy, and 18% received immunosuppressants without TPO-RAs. During follow up, 59% required rescue therapy and 35% experienced a bleeding event: major bleeds, 26%; moderate bleeds, 12%; and mild bleeds, 29%. The bleeding event rate per 100 person-months was 7.68 (95% CI 5.75–10.05) overall, 2.75 (1.66–4.30) for major bleeds, 0.58 (0.16–1.48) for moderate bleeds, and 4.35 (2.93–6.21) for mild bleeds. The most common bleeds were ecchymosis (event rate per 100 person-months [95% CI], 2.75 [1.66–4.30]), gastrointestinal (2.46 [1.44–3.95]), and menorrhagia (0.58 [0.16–1.48]).ConclusionsDespite receiving at least one currently available first-line and second-line therapy, in this US-based claims study of patients with primary ITP, a significant proportion continued to experience bleeding events and required rescue therapy. This analysis highlights significant unmet needs for novel therapies for the primary ITP patient population.
