Abstract Topic: 32. Platelet disorders
Background: At present, there are only relevant pre-market clinical studies for Hetrombopag (HET), as a new TPO receptor agonist (TPORA) made in China. How about the efficacy and safety in the real world? That’s the purpose of this study.
Aims: To observe the efficacy and safety of hetrombopag in relapse and refractory immune thrombocytopenia in the real world.
Methods: In the real world, patients with relapse and refractory immune thrombocytopenia (R/R ITP) were treated with HET, given orally at starting doses of 2.5 mg/day and 5.0 mg/day, respectively. The primary endpoint was the proportion of responders after 4 week, 8 weeks, and 12 weeks of treatment. Treatment response was defined as platelet count ≥50×109/L. The secondary endpoint was the safety of HET treatment. Median onset time was defined as the time when platelet count ≥30 × 109/L at least once and at least twice the baseline platelet count.
Results: A total of 50 patients with R/R ITP were enrolled and observed. Among them, the initial dose of 15 patients was 2.5 mg/d, but 11 patients had no responses after 2 weeks, and then dose was increased to 5 mg/d. Out of 50 patients, the median age was 47 (5-70) years old, 74% were women. The median course of ITP disease was 20 months (4 monts-40 years), and the mean platelet count was 16×109/L when enrolled. The platelet response rates at 4 week, 8 weeks, and 12 weeks of treatment were: 46%, 67%, and 71%, respectively (Table.1). The average number of platelets in patients increased with the prolongation of medication time. The median onset time was 7days.
At two weeks, the mean platelet count reached to 96×109/L. The mean platelet counts at 4 week, 8 week, and 12 week after treatment were 83×109/L, 91×109/L,104×109/L, respectively (Figure.1A). About adverse events (AEs), two cases had mild headache and one case had mild transaminase abnormality. We did not find the previously reported serious AEs.
Notably, there are 13 patients taking HET as the second line medicine. Among them, the response rate at 4th week (platelet counts≥50×109/L) was 56% (5/9), 71% (5/7) at 8th week, and 70% (7/10) at the twelfth week. The average platelet counts were 72, 110 and 82×109/L respectively, when 4,8 and 12weeks. It shows that the earlier the use of HET, the better the clinical effect (Figure.1B).
There were 8 patients converted to HET administration, who had no response to Eltrombopag previously. After conversion, 7 patients acquired clinical response, with an effective rate of 88%. The average platelet count before conversion was 25×109/L, and the average platelet counts at the 4th, 8th and 12th weeks after conversion were 208×109/L,171×109/L, and 196×109/L respectively (Figure.1B).
Summary/Conclusion: Hetrombopag is effective and safe in the treatment of R/R ITP in real world. The recommended initial dose is 5mg per day for ITP treatment, and there is a trend that the longer patients take HET, the higher the response rate. Secondly, it suggested that the earlier the use of HET, the better the clinical effect. Thirdly, for some patients with Eltrombopag invalid, clinical response can still be reacquired after conversion to HET, but more clinical data is needed to verify. Lastly, in the real world, the management of ITP patients should be strengthened to reduce the loss of follow-up, which will affect the therapeutic effect.
Keywords: ITP