By Anne McLeod, MD

2009-12-08

Immune thrombocytopenic purpura (ITP) has long been a condition with many treatment options. The challenge for physicians has been to choose the right therapy at the right time (including the difficult decision about timing of splenectomy), to know when to give up on one therapy and move on to something else, and to help patients deal with all of this uncertainty. It is with somewhat mixed feelings, then, that we embrace additional ITP treatment options — rituximab and the thrombopoietic agents. These medications have clearly demonstrated their efficacy in ITP, and this is exciting, but we do not know how best to use them. This year’s ITP Oral and Poster Sessions focus on who to treat, how long to treat, and what side effects to expect. 

Yesterday in the Disorders of Platelet Number or Function: New Therapies for ITP Oral Session moderated by Drs. Adam Cuker and Craig Kessler, Dr. David Kuter from Massachusetts General Hospital (abstract #679) presented final results from an open-label randomized study of romiplostim versus standard care in non-splenectomized patients with ITP. The study demonstrated a 9 percent incidence of splenectomy in the romiplostim group versus 36 percent in the standard-care group and a 11 percent treatment failure rate in the romiplostim group versus 30 percent in the standard-care group. The incidence of significant bleeding events was also lower in the romiplostim group.

Following this presentation, Dr. George Buchanan of the University of Texas Southwestern (abstract #680) described results of a randomized study in children, demonstrating the safety and efficacy of romiplostim in the treatment of pediatric chronic ITP. Twenty-two patients ranging in age from 22 months to 18 years were enrolled.  After 12 weeks, 88 percent of the romiplostim-treated group achieved a platelet count >50x109/L, versus none in the placebo-treated group. Although more studies in children are needed, this provides important evidence supporting the use of romiplostim in pediatric chronic ITP.

Long-term follow-up results were presented for eltrombopag and romiplostim. The EXTEND Study, presented by Dr. Mansoor Saleh from Georgia Cancer Specialists (abstract #682), demonstrated that oral eltrombopag treatment for up to two years effectively raised platelet counts, decreased bleeding symptoms, and was well-tolerated in chronic ITP. Dr. James Bussel from Weill Cornell Medical College (abstract #681) presented five-year follow-up results showing romiplostim-treated patients were able to maintain platelet counts within the target range, with minimal dose adjustments over five years. Romiplostim was well tolerated, and adverse events did not increase with longer duration of treatment. In Sunday’s Poster Session, Dr. Francesco Zaja (Udine, Italy) presented follow-up results from the ITP trial he discussed at the 2008 Plenary Session: a study of rituximab plus dexamethasone versus dexamethasone alone (abstract #2415).  Dr. Zaja and his colleagues observed no additional long-term toxicity.

There is no doubt that there are a lot of good ITP treatment options, but we have some confusing years ahead. As we gather answers to where new agents fit in ITP treatment algorithms, we will be better able to answer the key question our patients ask: “Which option is best for me?”

Dr. McLeod indicated no relevant conflicts of interest.

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