Additional efficacy analysis of avatrombopag phase III data for the treatment of adults with immune thrombocytopenia.

What is the context? Avatrombopag is a medicine that helps the body produce platelet cells, which are necessary for blood clotting.Avatrombopag is used to treat people with chronic immune thrombocytopenia (ITP); these patients have low numbers of platelet cells in their blood, so their blood may not clot efficiently, putting them at risk of uncontrolled bleeding.A phase III clinical study in patients with chronic ITP showed that platelet counts increased for most patients who were treated with avatrombopag; patients who had a platelet count ≥50 × 10⁹/L were considered to have a response to avatrombopag treatment.The present study analyzes data from a phase III clinical study to determine whether there are any characteristics that make a patient more or less likely to have a loss of response (LOR) while taking avatrombopag, whether the initial response to avatrombopag is stable, and how long the response lasts.For this analysis, LOR is defined as platelet count <30 × 10⁹/L for either four consecutive weeks or for two consecutive office visits while taking avatrombopag.What is new? In general, patient characteristics did not influence the likelihood of LOR.Patients who responded maintained their response for most of the time they were taking avatrombopag.Most patients did not experience LOR.What is the impact? The initial response to avatrombopag is stable and long-lasting in patients with chronic ITP.These findings indicate that patients with a variety of background characteristics can experience a durable platelet response with avatrombopag treatment.