In a recent real-world study published in Blood, thrombopoietin receptor agonists (TRA) were found to be effective in older patients with primary immune thrombocytopenia (ITP).
Given that the uncertainty of efficacy and safety of thrombopoietin receptor agonists in older patients with ITP, the investigators evaluated TRA response and switch, thrombotic/hemorrhagic risk, and sustained responses off-treatment in patients with ITP ≥60 years of age treated at 21 participating centers between February 2009 and April 2020. Patients were followed until death or the data cutoff date (November 1, 2020).
The study included 384 patients who were treated with eltrombopag (70.6%) or romiplostim (29.4%) as first TRA. The most common comorbidities were diabetes (28.1%), solid tumors (16.2%), and acute myocardial infarction (12%). At TRA initiation, the median platelet count was 20 × 109/L (range, 1-50 × 109/L) and 21.4% received concomitant ITP treatment (corticosteroids and/or immunoglobulins) for a median of 37 days (range, 5-120). The median duration of first TRA therapy was 1.2 years (range, 0.1-11.4).
After 3 months of treatment, 82.5% of eltrombopag and 74.3% romiplostim-treated patients achieved a response. After a median follow up of 2.7 years, 66.7% maintained the response. Approximately one-quarter of patients (22.2%) switched to the alternative TRA. After the switch, 83.3% of patients with treatment-resistant ITP had a response, and no cross-toxicity was observed.
A total of 34 major thromboses (3 fatal) in 18 patients and 14 major hemorrhages (none fatal) in 10 patients occurred and were associated with baseline thrombosis history (subdistribution hazard ratio [HR], 2.04; P =.05) and platelet count <20 × 109/L (subdistribution HR, 1.69; P =.04), respectively. A recurrent thrombotic event occurred in 15.6% of patients (incidence rate, 7.7 per 100 patient-years); all occurred in the absence of adequate antithrombotic secondary prophylaxis.
Among 62 (16.5%) patients who were responding to treatment who discontinued TRAs, 53 (13.8%) patients had sustained responses off-treatment, which were associated with TRA discontinuation in complete response (P <.001). Age ≥75 years (41.1% of patients) was associated with the more frequent start of TRAs in the persistent/acute phase and was not associated with response or thrombotic/hemorrhagic risk.
The authors concluded, “Overall, these findings provide important real-life evidence that TRAs may be effective and safe in older patients, with no fatal hemorrhages and with successful SROTs in a nonnegligible portion of patients. The risk of thrombosis remains considerable. The risk-benefit balance between thrombotic and bleeding events deserves a careful evaluation of the risk factors for both events before prescribing TRAs.”
Disclosure: The study author(s) declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Palandri F, Rossi E, Bartoletti D, et al. Real-world use of thrombopoietin receptor agonists in older patients with primary immune thrombocytopenia. Blood. 2021;138(7):571-583. doi:10.1182/blood.2021010735