When Less Is More: Intravenous Immune Globulin for the Treatment of New-Onset Pediatric Immune Thrombocytopenia

When less is more: Intravenous immune globulin for the treatment of new-onset pediatric immune thrombocytopeniaIntroduction Pediatric immune thrombocytopenia (ITP) is usually an acute disease which resolves spontaneously in about 80% of cases; with 20% having a chronic course, defined by a disease lasting over one year. Although some risk factors have been identified, it is still unclear what influences recovery, chronicity, or bleeding complications.

The rationale for treating ITP is to prevent intracranial hemorrhage (ICH) or other significant bleeding manifestations. Current medical treatment strategies for new onset pediatric ITP include observation alone, corticosteroids, anti-Rh (D) immune globulin, and intravenous immune globulin (IVIg), in varying dosage regimens between 0.8-2 gm/kg.

Higher dose of IVIG, associated with longer hospitalizations, increased costs, and potentially causes more side effects (e.g. headache, fatigue, vomiting, and hypotension). Yet if a higher dose is therapeutically superior, it would be preferred despite the higher costs and toxicity.

Aim We retrospectively compared durable response to treatment; defined as platelet count remains over 20*10⁹/for a period lasting >14 days, long term effects and adverse events, between the two IVIG dose regimens (1or 2gr/kg), given for new onset pediatric ITP in our pediatric tertiary center.

Methods The study included all children with newly diagnosed ITP, hospitalized in our tertiary center in Israel, between 2010-2020 and treated initially with IVIG.

Data was taken from electronic patient charts.

Results 168 children with newly diagnosed ITP were treated initially with IVIG. 82 received 1 gr/kg and 86, with 2 gr/kg. Baseline demographics and clinical characteristics of patients in both groups were similar.

There was no difference in durable response (platelet count>20*10⁹, > 14 days) between both groups (74.3% compared to 76.7%, p=0.72) and maximal platelet counts following treatment (235.3±169.4*10⁹ compared to 214.5± 182.31*10⁹, p=0.44).

Nor was any difference found in the percentage of patients with thrombocytopenia one year after diagnosis (chronic ITP); 29.3% in the 1gr/kg group, compared to 19.8% in the 2gr/kg group ( p=0.2) and in the percentage of those with chronic disease requiring treatment in the preceding month (13.4%% in the former compared to 8.1% in the later, p=0.32).

Logistic regression analysis demonstrated that there was no effect of the type of treatment on the treatment failure and development of chronic ITP.

There was no difference between those who were treated upfront with 2 gr/kg and those who were treated initially with 1 gr/kg and received the second 1gr/kg up to 3 days later.

As anticipated, adverse effects were more common those who received 2gr/kg.

Conclusion Initial treatment of newly diagnosed pediatric ITP using IVIG 1 gm/kg gives comparable results to the double dose of 2gm/kg in attaining a safe hemostatic threshold, for a similar duration of therapeutic effect and with less adverse effects and at a lower cost.

Yacobovich:Novartis Israel: Consultancy.