Efficacy and Safety of Eltrombopag in Persistent and Newly Diagnosed ITP

Background: Eltrombopag is a thrombopoietin receptor agonist approved for primary chronic ITP patients. Due to the non-existence of clinical trials using eltrombopag in persistent and newly diagnosed ITP, there are no clear data about its usefulness in this setting.

Aims: To evaluate efficacy and safety of eltrombopag in persistent, newly diagnosed and chronic ITP in routine clinical practice in Spain.

Methods: Two hundred and twenty adult ITP patients from thirty Spanish centers who had been treated with eltrombopag and included in the Spanish Eltrombopag Registry were retrospectively evaluated. This study was performed in accordance with the standards of the Helsinki declaration and approved by the Hospital Universitario de Burgos Ethics Committee.

Results:

Here we report efficacy and safety results of primary ITP Spanish Eltrombopag Registry cohort. According to the standard definition, patients were allocated to newly diagnosed (n=30), persistent (n=30) and chronic (n=160) ITP groups. Each group is described separately in Table I.

There are no statistical significant differences regarding response and duration of response among ITP groups. There is a trend towards a greater efficacy in newly diagnosed ITP with 93.3% of responses (platelet count ≥30 x10⁹/L and at least two-fold increase the baseline count and absence of bleeding) and 86.7% of complete responses (CR; platelet count >100 x 10⁹/L). Persistent ITP achieved 83.3% of responses and 80.0% of CR. Similarly 79.4% of responses with 73.1 of CR were observed in chronic ITP. Response rates were similar in all groups regardless all other studied parameters.

Another trend towards a longer response duration in persistent ITP was found, with a median of 424 (IQR, 288-664) days. Response durations were similar in chronic ITP (median, 370 days; IQR, 174-624) and in newly diagnosed ITP (median, 378 days; IQR, 154-485).

In newly diagnosed ITP, eight adverse events (AEs) with only three grade 3-4 AEs were observed. We reported three deaths; Two of them were due to upper respiratory tract infections in previously diagnosed pulmonary patients. A cerebral hemorrhage was the only death directly related to thrombocytopenia.

In persistent ITP, four grade 1-2 AEs and two grade 3-4 AEs (one stroke, one cerebral bleeding) were reported. The only observed death was secondary to the mentioned cerebral hemorrhage.

Twenty-one grade 1-2 AEs, ten grade 3-4 AEs and eight deaths (only two caused by bleeding) occurred in chronic ITP.

Conclusion:

Use of eltrombopag for treating persistent and newly diagnosed ITP is effective and safe. However, more studies are needed to confirm usefulness of TPO-RAs in this setting.