Results of a recent study suggest that in pediatric patients with treatment-naïve severe aplastic anemia (SAA), treatment with eltrombopag (EPAG) added to standard immunosuppressive therapy (IST) did not lead to better outcomes than were seen with treatment using IST alone. The study results were reported in the British Journal of Haematology.
The study was a subgroup analysis of an ongoing, prospective phase 1/2 trial (ClinicalTrials.gov Identifier: NCT01623167) examining EPAG added to IST in patients with SAA, with results compared to those of a historical cohort receiving IST only. This subgroup analysis focused on outcomes for patients younger than 18 years old who received EPAG plus IST in this trial, in comparison with those of pediatric patients in the historical IST-treated cohort. Results were also compared to those for adult patients receiving EPAG plus IST or IST only in the historical cohort. Several efficacy outcomes were evaluated.
There were 40 patients in the pediatric subgroup receiving EPAG plus IST and 87 pediatric patients examined from the historical IST-treated cohort. The median follow-up was 1432.5 days for patients receiving EPAG plus IST, and it was 2409 days for the historical cohort.
The overall response rate (ORR) at 6 months in pediatric patients receiving EPAG plus IST (70%) was similar that of the historical pediatric IST-treated cohort (72%; P =.78). Complete response rates at 6 months were also similar between these pediatric groups, with a rate of 30% for those receiving EPAG plus IST and a rate of 23% for the IST-treated cohort (P =.42). The ORR with EPAG plus IST was 82% for adult patients, compared with an ORR of 58% for adults in the historical IST-treated cohort (P ≤.001).
In pediatric patients receiving EPAG plus IST who had responded by 6 months, the event-free survival rate was significantly lower, at 57%, than it was for 6-month responders in the pediatric cohort receiving IST only (69%; P =.0499). Pediatric responders who received EPAG also showed a trend toward a higher relapse rate (43%) compared with the IST-treated pediatric cohort (27%; P =.0661). Overall survival and clonal evolution rates did not significantly differ between the pediatric groups.
“In adults, the addition of EPAG has offered significant improvements in response rates to >80%, but this result was not replicated in children,” the study investigators wrote in their report. They considered the rationale for the reduced efficiency with EPAG in children to not be clear, but they also indicated that children have historically tended to show better responses to IST than adults have.
“The data presented in this [nonrandomized] subgroup analysis do not support the addition of EPAG to IST for treatment-naïve SAA in children,” the study investigators concluded, even though, as they noted, this is a treatment regimen that has been approved by the US Food and Drug Administration for use in patients who are 2 years or older.
Groarke AM, Patel BA, Gutierrez-Rodrigues, et al. Eltrombopag added to immunosuppression for children with treatment-naive severe aplastic anaemia. Br J Haematol. 2021;192(3):605-614. doi:10.1111/bjh.17232