Secondary ITP complicates the clinical course of chronic LPDs in up to 5% of cases and is poorly responsive to conventional treatments.
Eltrombopag is effective in increasing platelet count to safe levels in most cases, thus postponing otherwise unnecessary chemotherapy.
Immune thrombocytopenia (ITP) secondary to chronic lymphoproliferative disorders (LPD) is poorly responsive to conventional treatments. We conducted a multicenter phase 2 prospective 24-week study in 18 patients with ITP secondary to LPD (sITP) to assess the safety and efficacy of eltrombopag. Responsive patients entered an extension study for up to 5 years. For inclusion patients should not necessitate cytotoxic treatment, and have platelet count < 30 x 109/L or bleeding. Eltrombopag was initiated at 50 mg/day, with a maximum of 150 mg/day. The primary endpoint was platelet response (R) after 4 weeks. Median age was 70 years (43-83), 14 patients had chronic lymphocytic leukemia (CLL), 2 classical Hodgkin's lymphoma, and 2 Waldenstrom macroglobulinemia. All patients had received previous ITP treatments. Response rate at week 4 was 78% (95% CI 58-97), with 50% of complete response (CR) (95% CI 43-57); respective results at week 24 were 59% (95% CI 36-82) with 30% of CR (95% CI 8-52). Median exposure time to eltrombopag was 16 months; median dose at week 4 and 24 was 50 mg (ranges 25-100 and 25-150). No > grade 2 adverse events were reported. Eltrombopag is active and well tolerated in ITP secondary to LPDs. ClinicalTrials.gov Identifier: NCT01610180.