Eltrombopag showed good safety and promising clinical activity in patients with immune thrombocytopenia (ITP) secondary to chronic lymphoproliferative disorders, according to results from a phase 2 trial.
Carlo Visco, MD, of the University of Verona (Italy), and colleagues investigated the efficacy and safety of eltrombopag in increasing platelet counts in patients with ITP that was secondary to chronic lymphoproliferative disorders. The findings were published in Blood.
The single-arm, open-label study included 18 patients with ITP secondary to chronic lymphocytic leukemia (14), Waldenstrom macroglobulinemia (2), and classical Hodgkin lymphoma (2). The median age at baseline was 70 years (range, 43-83 years), and all patients were previously treated with ITP.
Study participants were recruited from seven Italian centers from September 2012 to November 2015. Eligible participants were enrolled into an extension phase if a response was observed.
Study patients received oral eltrombopag at 50 mg daily, up to a maximum of 150 mg daily. At weeks 4 and 24, the median dose was 50 mg (ranges, 25-100 mg and 25-150 mg, respectively), with a median total exposure time of 16 months.
At 4 weeks, the researchers found that the platelet response rate was 78%, with a complete response rate of 50%.
After 24 weeks of therapy, the platelet response rate was 59%, with a complete response rate of 30%.
With respect to safety, the therapy was well tolerated, with no adverse events higher than grade 2 reported.
Fifteen patients discontinued therapy: eight due to loss of response, six for disease progression or death, and one for inefficacy and protocol violation, they reported.
The researchers acknowledged two key limitations of the study: the small sample size and lack of a comparison group. “Further prospective studies comparing eltrombopag to standard of care are needed to confirm our findings on the efficacy of this treatment and also to expand our knowledge on its safety, including the potential increased risk of thrombosis,” they wrote.
The study was funded by the Hematology Project Foundation, Vicenza. The authors reported financial affiliations with Amgen, Argenx, and Novartis.
SOURCE: Visco C et al. Blood. 2019 Sep 30. doi: 10.1182/blood.2019001617.