FDA Approves Avatrombopag for Thrombocytopenia in Adults with Chronic Liver Disease

Approval is based on results from the ADAPT-1 and ADAPT-2 studies

On 21 May 2018, the US Food and Drug Administration approved avatrombopag (Doptelet, AkaRx Inc.) for thrombocytopenia in adults with chronic liver disease scheduled to undergo a procedure.

Approval was based on two international, identically designed, randomised, double-blind, placebo-controlled trials, ADAPT-1 and ADAPT-2. Patients (n = 430) with chronic liver disease and thrombocytopenia received either avatrombopag (n = 274) or placebo (n = 156) daily for 5 days prior to a scheduled procedure and had at least 1 post-dose safety assessment. Patients were randomised (2:1) to avatrombopag or placebo and stratified according to hepatocellular cancer status and bleeding risk associated with the elective procedure (low, moderate, or high).

Patients randomised to avatrombopag received differential dosing based on mean platelet count at entry. Patients with a baseline platelet count less than 40,000/uL (low baseline platelet cohort) received avatrombopag 60 mg orally once daily for 5 consecutive days. Those with a baseline platelet count of 40,000 to less than 50,000/uL (high baseline platelet cohort) received avatrombopag 40 mg orally once daily for 5 consecutive days. Eligible patients were scheduled to undergo their procedure 5 to 8 days after the last dose of study drug.

The primary efficacy endpoint was the proportion of patients, or responders, who did not require a platelet transfusion or any rescue procedure for bleeding after randomisation and up to 7 days following an elective procedure.

In the low baseline platelet cohort, 66% and 69% of patients treated with avatrombopag responded in the ADAPT-1 and ADAPT-2 trials, respectively. For those receiving placebo, 23% (treatment difference 43%; 95% CI: 27, 58; p < 0.0001) and 35% (treatment difference 34%; 95% CI: 16, 52; p = 0.0006) responded in the ADAPT-1 and ADAPT-2 trials, respectively.

In the high baseline platelet cohort, 88% of avatrombopag-treated patients in both trials responded compared to 38% and 33% of placebo-treated patients. Treatment difference was 50% (95% CI: 32, 68; p < 0.0001) in the ADAPT-1 trial and 55% (95% CI: 37, 73; p < 0.0001) in the ADAPT-2 trial.

The most common adverse reactions reported in at least 3% of patients were pyrexia, abdominal pain, nausea, headache, fatigue, and peripheral oedema.

The recommended dose of avatrombopag is based on a patient’s platelet count prior to a scheduled procedure.

FDA granted this application priority review.

Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System.