Secondary ITP complicates the clinical course of chronic LPDs in up to 5% of patients and is poorly responsive to conventional treatments.
Eltrombopag is effective in increasing platelet count to safe levels in most patients, thus postponing otherwise unnecessary chemotherapy.
Immune thrombocytopenia (ITP) secondary to chronic lymphoproliferative disorders (LPDs) is poorly responsive to conventional treatments. We conducted a multicenter phase 2 prospective 24-week study in 18 patients with ITP secondary to LPDs to assess the safety and efficacy of eltrombopag. Responsive patients entered an extension study for up to 5 years. For inclusion, patients should not require cytotoxic treatment and should have a platelet count <30 × 109/L or have symptoms of bleeding. Eltrombopag was initiated at 50 mg/day, with a maximum of 150 mg/day. The primary end point was platelet response after 4 weeks. Median age was 70 years (range, 43-83 years), and 14 patients had chronic lymphocytic leukemia, 2 had classic Hodgkin lymphoma, and 2 had Waldenström macroglobulinemia. All patients had received previous ITP treatments. Response rate at week 4 was 78% (95% confidence interval [CI], 58%-97%), with 50% of patients having a complete response (CR) (95% CI, 43%-57%); respective results at week 24 were 59% (95% CI, 36%-82%) with 30% reaching a CR (95% CI, 8%-52%). Median exposure to eltrombopag was 16 months; median dose at week 4 was 50 mg/day (range, 25-100 mg/day), and at week 24, it was 50 mg/day (range, 25-150 mg/day). No grade >2 adverse events were reported. Eltrombopag is active and well tolerated in ITP secondary to LPDs. This trial was registered at www.clinicaltrials.gov as #NCT01610180.