Researchers affiliated with an international study (RAISE) have reported that long-term use of Promacta® (eltrombopag, Revolade®) is safe and effective for the treatment of chronic idiopathic thrombocytopenic purpura (ITP). This study was presented at the annual meeting of the American Society of Hematology (ASH) in San Francisco on December 8, 2008.[1] 

Promacta is an oral non-peptide thrombopoietin receptor agonist with a low immunogenic potential.  Phase I and II studies have suggested that Promacta is a well-tolerated oral TPO-mimetic with excellent response rates in the treatment of chronic ITP. Other similar new agents for treatment of chronic ITP include Nplate™ (romiplostim), which has been approved by the U.S. Food and Drug Administration for this purpose.

The current study was a randomized, double-blind, placebo-controlled Phase III trial that evaluated Promacta in 197 patients with previously treated ITP. The randomization was carried out on a 2:1 basis. All patients in this study had platelet counts less than 30,000. Half of the patients had platelet counts less than 15,000, half were receiving therapy for ITP, and 35% had been splenectomized. Treatment was to be carried out for six months. The median baseline platelet counts were 16,000 in both the Promacta (n=135) and placebo group (n-62). The main findings of this study were as follows:

• In the control group, the median platelet counts did not exceed 30,000.
• In the Promacta group, the median platelet count was 36,000 after the first week and ranged between 52 and 91,000 for the remainder of the study. Platelet counts as high as 400,000 were achieved with Promacta.
• More than half of all patients receiving Promacta stopped or had dose-reduction of concurrent therapies for ITP.
• Any bleeding and significant bleeding was significantly less in patients receiving Promacta.
• 19% of patients in the Promacta group required rescue therapy compared with 40% in the control group.
• After discontinuing Promacta platelet counts returned to baseline within two weeks.
• Splenectomy, baseline platelet counts, and other medications did not affect response to Promacta.
• Total adverse events were not different between the Promacta and placebo groups.
• Dyspepsia and peripheral edema due to steroids were less frequent in the Promacta group.
• Hepatobiliary abnormalities were 13% in the in Promacta group and 7% in the placebo group.
• One death from hemorrhage occurred in the placebo group and none in the Promacta group.

These authors concluded: “Eltrombopag was well-tolerated, with a similar safety profile to placebo, and is an important new treatment option for patients with chronic ITP”

Comments: These data are convincing that eltrombopag is effective for the long-term treatment of patients with chronic ITP.

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