Thrombopoietin Receptor Agonists for Thrombocytopenia in Pediatric Hematologic Malignancies

Thrombopoietin receptor agonists (TPO-RAs) have demonstrated efficacy in treating clinically significant thrombocytopenia, including chemotherapy-induced thrombocytopenia in adults. However, data regarding their safety and efficacy in pediatric, adolescents, and young adult (AYA) patients with hematologic malignancies are limited.

We retrospectively identified 15 pediatric and AYA patients aged 25 years or younger with hematologic malignancies treated with a TPO-RA at UCSF Benioff Children's Hospitals between 2015 and 2023. Platelet counts and transfusion requirements were compared before and after TPO-RA therapy.

The median age at TPO-RA initiation was 16 years (range: 7-25 years). Nine patients (60%) had a history of bleeding or comorbidity that predisposed to severe bleeding risk. Eleven patients received romiplostim and four patients received eltrombopag. The median platelet count significantly increased from 24 × 10⁹/L at baseline to 54 × 10⁹/L after 3 weeks of any TPO-RA therapy (p = 0.029). Monthly platelet transfusion requirements significantly decreased from a median of 15 to two units after TPO-RA therapy (p = 0.007). Fourteen of the 15 patients (93%) achieved a sustained platelet count >50,000/µL within 8 weeks, with a median time to response of 3 weeks. No TPO-RA-related adverse events were observed.

TPO-RAs were effective in managing refractory thrombocytopenia in pediatric and young adult patients being treated for hematologic malignancies, with a favorable safety profile, even among patients with multiple comorbidities. These findings warrant further investigation through prospective clinical trials to confirm efficacy and establish clinical guidelines for this population.