ABSTRACT
Immune thrombocytopenia (ITP) is characterized by low platelet counts (PLTs) and an increased risk of bleeding. Fostamatinib, a spleen tyrosine kinase inhibitor, has been approved as a second-line treatment for ITP. Real-world data on fostamatinib are lacking. This observational, retrospective, multicentre study, conducted in the Andalusia region of Spain, evaluated 44 adult primary ITP patients (47.7% female; median age 58 years; newly diagnosed ITP 6.8%; persistent 13.6%; chronic 79.5%; median four prior treatments) after ≥ 4 weeks of fostamatinib therapy. The median PLT at the initiation of fostamatinib was 15 × 109/L. Common reasons for starting fostamatinib were refractoriness or intolerance to prior therapy, oral medication preference, history of thrombosis and cardiovascular risk. Dosing was individualized based on efficacy and tolerance. After 2 weeks, global response rate was 56.8% (response and complete response). Response rates were 70.5%, 62.5% and 64% at 4 weeks, 12 weeks and at the end of the study respectively. Adverse events were mild, and no patients discontinued as a result. This real-world study demonstrated a response rate similar to fostamatinib as seen in the pivotal clinical trials while including newly diagnosed patients and allowing for individualized dosing.
Subject(s)
Aminopyridines , Morpholines , Purpura, Thrombocytopenic, Idiopathic , Pyridines , Humans , Middle Aged , Female , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Male , Spain , Aminopyridines/therapeutic use , Aminopyridines/adverse effects , Aged , Morpholines/therapeutic use , Morpholines/adverse effects , Retrospective Studies , Adult , Pyridines/therapeutic use , Pyridines/adverse effects , Oxazines/therapeutic use , Oxazines/adverse effects , Pyrimidines/therapeutic use , Pyrimidines/adverse effects , Treatment Outcome , Protein Kinase Inhibitors/therapeutic use , Protein Kinase Inhibitors/adverse effects , Aged, 80 and overABSTRACT
: Thrombopoietin receptor agonist (TPO-RAs) have demonstrated good efficacy and tolerance in clinical trials in refractory chronic primary immune thrombocytopenia (ITP) or chronic ITP with contraindication for splenectomy. No head-to-head study is available, and differences in trials design do not allow comparisons. Information on the use of TPO-RAs in nonchronic ITP is scant. We described our experience with TPO-RAs in ITP (chronic, persistent and newly diagnosed ITP) in routine clinical practice. Retrospective series of 100 adult ITP patients was analysed; 41 treated with eltrombopag, 37 with romiplostim and 22 with both. Response-related and safety variables were evaluated. With a median follow-up of 86.5 weeks (interquartile range, 34.3-128 weeks), no differences were found in response rate, time to response, stability of response or response duration based on the type of TPO-RA used. Of all, 25% of patients with newly diagnosed or persistent ITP and 7.2% with chronic responded and maintained their response when TPO-RAs were stopped. Regarding safety, two developed bone marrow fibrosis grade 3, with loss of response to both drugs. Incidence of vascular events was 7%. Both TPO-RAs may be useful in all types of ITP, not only chronic but also persistent and newly diagnosed. Similar results were noted in efficacy and safety variables for both drugs.
