From the Journals

Avatrombopag cut procedure-related transfusions in patients with thrombocytopenia, chronic liver disease

Publish date: August 30, 2018
By
Amy Karon

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Avatrombopaq looks good with some caveats

Thrombocytopenia in cirrhosis is frequent and multifactorial and includes sequestration in the spleen, reduced liver-derived thrombopoietin, bone marrow toxicity, and autoimmunity towards platelets. Severe thrombocytopenia (less than 50/nL) is rare in cirrhotic patients, but when it occurs may prevent required procedures from being performed or require platelet transfusions, which are associated with significant risks.

Dr. Hans L. Tillmann


Previous attempts to increase platelets in cirrhotic patients with thrombopoietin agonists were halted because of increased frequency of portal vein thrombosis and hepatic decompensation.
Now avatrombopag has been specifically licensed with a 5-day regimen to increase platelets prior to elective interventions in severely thrombocytopenic (less than 50/nL) patients with chronic liver disease with a seemingly better safety profile than earlier treatments and good efficacy. The patient groups studied in the licensing trial had slightly milder but not significantly different liver disease, compared with those in the eltrombopag studies. The key difference was a pretreatment requirement of a portal vein flow of more than 10 cm/sec prior to enrollment, which likely reduced the risk of portal vein thrombosis. It is important that providers ready to use avatrombopag are aware of this.

Importantly, no data are currently available for patients with a Model for End-Stage Liver Disease score greater than 24, and very limited data are available for patients with Child B and Child C cirrhosis.

Given this limitation, careful judgment will be needed; a pretreatment portal vein flow may be advisable, though not a label requirement.

An observational study, NCT03554759, in patients with chronic liver disease and thrombocytopenia is ongoing and will further confirm the likely safety of avatrombopag.

Hans L. Tillmann, MD, is a clinical associate professor, East Carolina University, Greenville, and staff physician, Greenville (N.C.) VA Health Care Center. He has no relevant conflicts of interest.


 

FROM GASTROENTEROLOGY

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 Gastroenterology.

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. doi: 10.1053/j.gastro.2018.05.025.

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