Core Study:
To demonstrate that the efficacy of avatrombopag (in addition to standard of care) is superior to placebo (in addition to standard of care) for the treatment of adult participants with chronic immune thrombocytopenia (idiopathic thrombocytopenic purpura) (ITP) as measured by cumulative number of weeks of platelet response over 6 months of once daily treatment in adults participants who received at least 1 prior ITP therapy.
Extension Phase:
To evaluate the safety and tolerability of long-term therapy with avatrombopag in participants with chronic ITP (cITP).
Avatrombopag, an oral thrombopoietin receptor agonist, was compared with placebo in a 6-month, multicentre, randomised, double-blind, parallel-group Phase 3 study, with an open-label extension phase, to assess the efficacy and safety of avatrombopag (20 mg/day) in adults with chronic immune thrombocytopenia (ITP) and a platelet count <30 × 109 /l (ClinicalTrials.gov identifier NCT01438840). The primary endpoint was the cumulative number of weeks of platelet response (platelet count ≥50 × 109 /l) without rescue therapy for bleeding; secondary endpoints included platelet response rate at day 8 and reductions in the use of concomitant medications. Amongst the 49 patients randomised, avatrombopag (N = 32) was superior to placebo (N = 17) in the median cumulative number of weeks of platelet response (12·4 vs. 0·0 weeks, respectively; P < 0·0001). At day 8, a greater platelet response rate was also observed for patients treated with avatrombopag compared with placebo (65·63% vs. 0·0%; P < 0·0001), and use of concomitant ITP medications was also reduced amongst patients receiving avatrombopag. The safety profile of avatrombopag was consistent with Phase 2 studies; the most common adverse events were headache and contusion. Overall, avatrombopag was well tolerated and efficacious for the treatment of chronic ITP.
To demonstrate that the efficacy of avatrombopag (in addition to standard of care) is superior to placebo (in addition to standard of care) for the treatment of adult participants with chronic immune thrombocytopenia (idiopathic thrombocytopenic purpura) (ITP) as measured by cumulative number of weeks of platelet response over 6 months of once daily treatment in adults participants who received at least 1 prior ITP therapy.
Extension Phase:
To evaluate the safety and tolerability of long-term therapy with avatrombopag in participants with chronic ITP (cITP).
