Once-daily treatment with the oral second-generation thrombopoietin agonist avatrombopag (Doptelet) significantly reduced the need for platelet transfusion and rescue therapy for up to 7 days after patients with chronic liver disease and thrombocytopenia underwent scheduled procedures, according to the results of two international, randomized, double-blind, phase III, placebo-controlled trials reported in the September issue of.
SOURCE: AMERICAN GASTROENTEROLOGICAL ASSOCIATION
In the ADAPT-1 trial, 66% of patients in the 60-mg arm met this primary endpoint, as did 88% of patients who received 40 mg for less severe thrombocytopenia, versus 23% and 38% of the placebo arms, respectively (P less than .001 for each comparison). In the ADAPT-2 trial, 69% of the 60-mg group met the primary endpoint, as did 88% of the 40-mg group, versus 35% and 33% of the respective placebo groups (P less than .001 for each comparison).
These results led the Food and Drug Administration to approve avatrombopag in May 2018 under its priority review process. The novel therapy “may be a safe and effective alternative to platelet transfusions” that could simplify the clinical management of patients with chronic liver disease and thrombocytopenia, Norah Terrault, MD, MPH, and her associates wrote in Gastroenterology.
The ADAPT-1 study included 231 patients, while ADAPT-2 included 204 patients. In each trial, patients were randomized on a 2:1 basis to receive oral avatrombopag or placebo once daily for 5 consecutive days. Patients in the intervention arms received 60 mg avatrombopag if their baseline platelet count was less than 40 x 109 per liter, and 40 mg if their baseline platelet count was 40-50 x 109 per liter. Procedures were scheduled for 10-13 days after treatment initiation.
“Platelet counts increased by [treatment] day 4, peaked at days 10-13, and then returned to baseline levels by day 35,” the researchers reported. Among ADAPT-1 patients with low baseline counts, 69% of avatrombopag recipients reached a prespecified target of at least 50 x 109 platelets per liter on their procedure day, versus 4% of placebo recipients (P less than .0001). Corresponding proportions in ADAPT-2 were 67% and 7%, respectively (P less than .0001). Among patients with higher baseline counts, 88% and 20% achieved the target, respectively, in ADAPT-1 (P less than .0001), as did 93% versus 39%, respectively, in ADAPT-2 (P less than .0001).
Avatrombopag and placebo produced similar rates of treatment-emergent adverse events. These most often consisted of abdominal pain, dyspepsia, nausea, pyrexia, dizziness, and headache. Only three avatrombopag patients developed platelet counts above 200 x 109 per liter, and they all remained asymptomatic, the investigators said.
Dova Pharmaceuticals makes avatrombopag and funded medical writing support. Dr. Terrault and three coinvestigators disclosed ties to AbbVie, Allergan, Bristol-Myers Squibb, Eisai, Gilead, Merck, and other pharmaceutical companies. One coinvestigator is chief medical officer of Dova, helped analyze the data and write the manuscript, and gave final approval of the submitted version.
SOURCE: Terrault N et al. Gastroenterology. 2018 May 17. .