Patients with thrombocytopenia and chronic liver disease (CLD) may require platelet transfusions before scheduled procedures to decrease risk of bleeding. We performed 2 randomized, placebo-controlled, phase 3 trials in patients with thrombocytopenia and CLD undergoing scheduled procedures to evaluate the safety and efficacy of avatrombopag in increasing platelet counts in this patient population.

In the ADAPT-1 and ADAPT-2 studies, adults with thrombocytopenia and CLD (n = 231 and n = 204, respectively) were in 1 of 2 cohorts according to their baseline platelet count (below 40 × 10/L or 40 to below 50 × 10/L) and within each cohort were randomized (2:1) to receive 5 daily doses of avatrombopag (60 mg if baseline platelet count below 40 × 10/L or 40 mg if 40 to below 50 × 10/L) or placebo. ADAPT-1 was conducted at 75 study sites in 20 countries, from February 2014 through January 2017, and ADAPT-2 was conducted at 74 sites in 16 countries, from December 2013 through January 2017. The primary endpoint was the proportion of patients not requiring platelet transfusions or rescue procedures for bleeding up to 7 days after a scheduled procedure.

In the ADAPT-1 study, 65.6% of patients who received 60 mg avatrombopag and 88.1% of patients who received 40 mg avatrombopag met the primary endpoint compared with 22.9% and 38.2% of patients receiving placebo, respectively (P < .0001 for both). In the ADAPT-2 study, 68.6% of patients who received 60 mg avatrombopag and 87.9% of patients who received 40 mg avatrombopag met the primary endpoint compared with 34.9% and 33.3% of patients who received placebo, respectively (P < .001 for both). Avatrombopag led to a measured increase in platelet counts and increased the proportion of patients who achieved the target platelet count ≥ 50 × 10/L on procedure day vs placebo. The incidence and severity of adverse events were similar for the avatrombopag and placebo groups and were consistent with those expected in the CLD population.

In 2 phase 3 randomized trials, avatrombopag was superior to placebo in reducing the need for platelet transfusions or rescue procedures for bleeding in patients with thrombocytopenia and CLD undergoing a scheduled procedure. ClinicalTrials.gov nos.: NCT01972529 and NCT01976104.