Adapted guideline for the diagnosis and treatment of primary immune thrombocytopenia for Chinese children (2021)

The early and rapid response to daratumumab in children with chronic refractory immune thrombocytopenia from a referral single centre of China

Chronic refractory primary immune thrombocytopenia (CRITP) is currently defined as refractory to multiple therapeutic of second-line agents with or without splenectomy, faced with the threat of severe bleeding and challenging to obtain effective treatment. Although stable and effective drug therapy is needed, it is tough to find one. Daratumumab (Dara), an anti-CD38 monoclonal antibody presented the target cloned plasma cells in multiple myeloma, has also been reported to be effective in refractory autoimmune cytopenia in some case or series reports and ongoing clinical trials for adult patients with CRITP. Here, we report the early and durable response of Dara combination with avatrombopag in three CRITP patients (2 male and 1 female aged 12, 5 and 7 years, respectively) in our centre, with a follow-up period of more than 25 weeks. Before Dara, the duration of immune thrombocytopenia was 9, 1.4 and 4 years, respectively, a baseline platelet count of 4, 6, 9 × 109/L, the bleeding score was all above level 2 and the number of previous drugs was >3. The time to response (R: Plt ≥30 × 109/L with at least a twofold increase in the baseline count) of Dara was on Day 45, 6 and 4 and achieved complete response (CR: Plt ≥100 × 109/L) on Day 51, 6 and 8, the sustained response (SR: Plt >30 × 109/L following Dara at ≥75% of the platelet count assessment at follow-up end-point since the patient achieved response) was 48, 175 and 204 days with the follow-up time of 39.1, 25.9 and 29.7 weeks. The bleeding score decreased from grade 3 to grade 0 during follow-up. No significant treatment-related adverse events were found during follow-up. Dara combination with avatrombopag may be a safe and efficacious therapy for children with CRITP, but it needs to be further explored.

The Differences of Serum Thrombopoietin Levels Between Acquired Aplastic Anemia and Immune Thrombocytopenia in Pediatric Patients

Thrombopoietin (TPO) is the critical regulator of platelet production. However, the role of TPO in pediatric patients with thrombocytopenic disorders has not been fully elucidated. In the present study, we attempted to investigate serum TPO levels in patients with acquired aplastic anemia (aAA) and immune thrombocytopenia (ITP). We analyzed the endogenous plasma concentration of TPO and platelet count at the time of TPO measurement in 166 patients with aAA and 280 patients with ITP retrospectively. We further observed a correlation between platelet counts and TPO. Serum TPO levels were significantly higher in aAA compared with ITP (1142 vs. 77.99 pg/mL, P<0.001). In patients with aAA, an elevation for TPO levels in very severe AA (VSAA) was seen when compared with non-severe AA (NSAA) (1360 vs. 984.4 pg/mL, P<0.05). In contrast, the circulating TPO levels with chronic ITP (CITP) showed a decrease than newly diagnosed ITP (NITP) and persistent ITP (PITP) (62.28 vs. 81.56 pg/mL, P<0.01, 62.28 vs. 87.82 pg/mL, P<0.05, respectively). There was a negative correlation between platelet counts and TPO levels in aAA (rs=-0.3325, P<0.001) as well as ITP (rs=-0.2570, P<0.001). Especially, TPO levels were inversely correlated with platelet counts in NSAA (rs=-0.3672, P<0.001) and NITP (rs=-0.3316, P<0.001). After grouping by age or sex, there were no statistical differences in aAA or ITP. Serum TPO levels were markedly elevated in pediatric patients with aAA compared with ITP. It was higher in VSAA and lower in CITP, suggesting that serum TPO level could play a role in classifying disease severity or clinical course in aAA and ITP.

Efficacy and safety of avatrombopag in Chinese children with persistent and chronic primary immune thrombocytopenia: A multicentre observational retrospective study in China

Avatrombopag (AVA) is a novel thrombopoietin receptor agonist (TPO-RA) that has been recently approved as a second-line therapy for immune thrombocytopenia (ITP) in adults; however, its safety and efficacy data in children are lacking. Here, we demonstrated the efficacy and safety of AVA as second-line therapy in children with ITP. A multicentre, retrospective, observational study was conducted in children with persistent or chronic ITP who did not respond to or relapsed from previous treatment and were treated with AVA for at least 12 weeks between August 2020 and December 2022. The outcomes were the responses (defined as achieving a platelet count ≥30 × 109/L, twofold increase in platelet count from baseline and absence of bleeding), including rapid response within 4 weeks, sustained response at weeks 12 and 24, bleeding control and adverse events (AEs). Thirty-four (18 males) patients with a mean age of 6.3 (range: 1.9-15.3) years were enrolled. The median number of previous treatment types was four (range: 1-6), and 41.2% patients switched from other TPO-RAs. Within 4 weeks, overall response (OR) was achieved in 79.4% patients and complete response (CR, defined as a platelet count ≥100 × 109/L and the absence of bleeding) in 67.7% patients with a median response time of 7 (range: 1-27) days. At 12 weeks, OR was achieved in 88.2%, CR in 76.5% and sustained response in 44% of patients. At 24 weeks, 22/34 (64.7%) patients who achieved a response and were followed up for 24 weeks were evaluated; 12/22 (54.55%) achieved a sustained response. During AVA therapy, median platelet counts increased by week 1 and were maintained throughout the treatment period. The proportion of patients with grade 1-3 bleeding decreased from 52.95% at baseline to 2.94% at 12 weeks, while concomitant ITP medications decreased from 36.47% at baseline to 8.82% at 12 weeks, with only 9 (26.47%) patients receiving rescue therapy 23 times within 12 weeks. There were 61.8% patients with 59 AEs: 29.8% with Common Terminology Criteria for Adverse Events grade 1 and the rest with grade 2. These findings show that AVA could achieve a rapid and sustained response in children with persistent or chronic ITP as a second-line treatment, with good clinical bleeding control and reduction of concomitant ITP therapy, without significant AEs.

Long-term eltrombopag in children with chronic immune thrombocytopenia: A single-centre extended real-life observational study in China

We have previously confirmed the efficacy and safety of eltrombopag (ELT) in children with chronic immune thrombocytopenia (cITP). However, data on both long-term exposure and early use of TPO-RAs are lacking, so further 'field-practice' evidence on treatment is required. Here, we report the long-term follow-up results (between September 2018 and June 2023) of our previous study. The main objective of this study was to retrospectively review our large institutional experience with ITP patients previously enrolled in our paediatric cITP study. We had more than 3 years of follow-up by June 2023 for treatment patterns and outcomes. A total of 65 patients (28 males) were enrolled, with a median age at ELT initiation of 6.34 (range 1.65, 14.13) years and a follow-up of 47.07 (36.00, 57.00) months, with 40.36 (10.53, 56.83) months of ELT therapy at the time of analysis. In total, 29.23% (19/65) of patients discontinued ELT due to stable response, and 18.46% (12/65) of patients switched to other ITP therapies due to loss of response (LOR) after 19.13 (14.53, 26.37) months. Of the 19 patients who discontinued ELT due to a stable response, 24.62% (16/65) achieved a 12 m sustained response off-treatment (SRoT); the last recorded platelet count ranged from 56 to 166 × 109 /L (median 107 × 109/L); and 4.62% (3/65) patients relapsed at 5, 6 and 9 months after discontinuation. Of the 12 patients who LOR to ELT after 19.13 (14.53, 26.37) months of therapy, four switched to avatrombopag, three switched to hetrombopag, two switched to traditional Chinese medicine (TCM), one underwent splenectomy and two received additional prednisolone under ELT treatment. Thirty-four patients who tapered and maintained a durable response. The patients with LOR and the patients with tapering were compared; the platelet count at the start of ELT is lower, and the time to response is longer in the patients with LOR. The platelet count at the start of ELT and the time to response may be the predictive factors for LOR during ELT treatment. We report more than 3 years of long-term clinical data on children with cITP using ELT. These data do not raise any new safety concerns regarding the long-term use of ELT in children with cITP.

Spotlight on eltrombopag concentration in pediatric immune thrombocytopenia: A single-center observational study in China

Importance

Eltrombopag has been recommended for pediatric immune thrombocytopenia (ITP). Response and adverse drug reactions (ADRs) varied widely between individuals, even at the same dose of eltrombopag. The appropriate eltrombopag concentration in ITP has not been reported.

Objective

This study aims to explore the appropriate eltrombopag concentration in pediatric ITP.

Methods

This was a single-center, prospective cohort study. Children diagnosed with refractory persistent/chronic ITP and platelet count < 30×109/L were treated with eltrombopag and followed up for at least 2 months. Concentration was detected by high-performance liquid chromatography-mass spectrometry at least 2 weeks after eltrombopag. The clinical characteristics-concentration, concentration-response, and concentration-ADRs were analyzed.

Results

A total of 30 patients were enrolled, comprising 13 males and 17 females, with a median age of 72 (45‒94) months. The median dose and concentration were 1.39 (1.09‒1.56) mg/kg and 2.70 (2.25‒4.13) mg/L, respectively. Of the enrolled patients, 14 responded to treatment, whereas 16 did not. Additionally, five experienced adverse drug reactions. No linear correlation was observed between eltrombopag concentration and clinical characteristics. The concentration was lower in the response group than in the nonresponse group, but there was no significant difference (t = 0.755, P = 0.457). Patients who experienced ADRs had a higher concentration than those without ADRs (t = 2.538, P = 0.017). The area under the receiver operating characteristic curve of ADRs was 0.78 (95% confidence interval: 0.56‒1.00). Youden's index identified the cutoff point as 4.33 mg/L, with a sensitivity of 88% and a specificity of 60%. Logistic regression analysis demonstrated that a higher platelet count before eltrombopag predicted a favorable response.

Interpretation

Eltrombopag proves efficacious and well-tolerated for treating pediatric ITP. However, prolonged and high-dose administration may increase the likelihood of ADRs. Thus, examining the appropriate eltrombopag concentration assists in directing individualized management of pediatric ITP.

Predicting the efficacy of glucocorticoids in pediatric primary immune thrombocytopenia using plasma proteomics

Objective

Primary immune thrombocytopenia (ITP) is the most common acquired autoimmune bleeding disorder among children. While glucocorticoids are the primary first-line treatment for ITP treatment, they prove ineffective in certain patients. The challenge of identifying biomarkers capable of early prediction regarding the response to glucocorticoid therapy in ITP persists. This study aimed to identify ideal biomarkers for predicting glucocorticoid efficacy in patients with ITP using plasma proteomics.

Methods

A four-dimensional data-independent acquisition approach was performed to determine the differentially expressed proteins in plasma samples collected from glucocorticoid-sensitive (GCS) (n=18) and glucocorticoid-resistant (GCR) (n=17) children with ITP treated with prednisone. The significantly differentially expressed proteins were selected for enzyme-linked immunosorbent assay validation in a cohort conprising 65 samples(30 healthy controls, 18 GCS and 17 GCR children with ITP). Receiver operating characteristics curves, calibration curves, and clinical decision curve analysis were used to determine the diagnostic efficacy of this method.

Results

47 differentially expressed proteins (36 up-regulated and 11 down-regulated) were identified in the GCR group compared with the GCS group. The significantly differentially expressed proteins myosin heavy chain 9 (MYH9) and fetuin B (FETUB) were selected for enzyme-linked immunosorbent assay validation. The validation results were consistent with the proteomics analyses. Compared with the GCS group, the GCR group exhibited a significantly reduced the plasma concentration of MYH9 and elevated the plasma concentration of FETUB. Furthermore, the receiver operating characteristics curves, calibration curves, and clinical decision curve analysis demonstrated good diagnostic efficacy of these validated biomarkers.

Conclusion

This study contributes to the establishment of objective biological indicators for precision therapy in children with ITP. More importantly, the proteins MYH9 and FETUB hold potential as a foundation for making informed decisions regarding alternative treatments for drugresistant patients, thereby preventing treatment delays.

Development, Evaluation, and impLemenTation for guideline adaptation: a quality improvement protocol for the DELTA study in global health practice

BACKGROUND

Guideline adaptation is an emerging field to provide more appropriate recommendations for local clinical practice quality and to promote global health equity. However, its utilization status, adaptation procedures, and related materials remain to be studied.

METHODS

This study developed a quality improvement protocol for a study as the Development, Evaluation, and impLemenTation for guideline Adaptation (DELTA) study. Current adapted clinical practice guidelines (CPGs) will be systematically searched. Their characteristics, utilization status, and adaptation procedures will be extracted, compared, and analyzed. Whether these adapted CPGs rigorously followed the instruments and steps of adaptation frameworks will also be appraised. In addition, the advantages and limitations of current adaptation methods and their suitable application situations will be analyzed. In addition, future perspectives as DELTA series and DELTA system, aiming for comprehensively evaluating current needs for guideline adaptation and developing a unified framework and related materials were proposed to improve the acceptability, applicability, and implementation of guideline adaptation in clinical practice. The DELTA series are divided into four phases: phase I in analyzing status, characteristics, and procedures and completeness of adapted CPGs; phase II in analyzing differences, heterogeneity, and implementation between adapted and original CPGs; and phase III in collecting, analyzing, and comparing all available adaptation materials. With these research bases, an international working group will be established in phase IV and will develop unified guideline adaptation materials after Delphi consensus, including adaptation frameworks, appraisal tools and checklists, registries, and databases.

DISCUSSION

Guideline adaptation has been advanced as an efficient way to guide local clinical practice. However, it still faces several major challenges. The proposed DELTA study, series, and system will further contribute to this emerging topic.

TRIAL REGISTRATION

 This study has been registered by the PROSPERO international database. https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=400170 .

Transient increase in platelet counts associated with COVID-19 infection during TPO-RA as the second-line treatment in children with ITP

The thrombopoietin receptor agonists (TPO-RA) were recommended for primary immune thrombocytopenia (ITP) during the pandemic of COVID-19. However, the incidence of thrombocytosis and thrombosis was sporadically reported in the chronic immune thrombocytopenia (CITP) patients receiving TPO-RA during the COVID-19 infection. With the local prevalence of COVID-19 in December 2022 in the Beijing area, we got more powerful evidence about the change in platelet (Plt) counts associated with COVID-19 infection. A single-centre observational cohort study was performed from the beginning of December 2022 to the end of February 2023 to enrol CITP children treated with TPO-RA alone as the second-line treatment and suffering from the COVID-19 infection in December 2022. The Plt counts before, during and after COVID-19 infection were collected. In total, 67 (34 males and 33 females) patients with 8.10 (2.15, 15.70) years of age were enrolled. Sixty-three patients who had responded to the TPO-RA showed a transient increase in Plt counts after the infection of COVID-19. The time of starting to increase was on Day 3 (2, 7), and to the peak level on Day 14 (7, 19) of infection with the peak Plt count was 289 (88, 1974) × 109 /L. With at least 2 months observation period from COVID-19 infection, the Plt counts of 100% (63/63) patients declined to the baseline on Day 25 (14, 41). The phenomenon of transient increase in Plt counts has been shown in the CITP children who responded to TPO-RA when suffering from COVID-19 infection.

Gut microbiota alterations in children and their relationship with primary immune thrombocytopenia

Introduction

Gut microbiota reportedly play a critical role in some autoimmune diseases by maintaining immune homeostasis. Only a few studies have examined the correlation between gut microbiota and the onset of primary immune thrombocytopenia (ITP), especially in children. The purpose of this study was to investigate changes in the composition and diversity of the fecal microbiota of children with ITP, as well as the correlation between such microbiota and the onset of ITP.

Methods

Twenty-five children newly diagnosed with ITP and 16 healthy volunteers (controls) were selected for the study. Fresh stool samples were collected to identify changes in the composition and diversity of gut microbiota as well as for potential correlation analysis.

Results

In ITP patients, the phyla that were most frequently encountered were Firmicutes (54.3%), followed by Actinobacteria (19.79%), Bacteriodetes (16.06%), and Proteobacteria (8.75%). The phyla that were predominantly found in the controls were, Firmicutes (45.84%), Actinobacteria (40.15%), Bacteriodetes (3.42%), and Proteobacteria (10.23%). Compared with those of the controls, the proportions of Firmicutes and Bacteriodetes in the gut microbiota of ITP patients were increased while the proportions of Actinobacteria and Proteobacteria were decreased. Furthermore, gut microbiota in ITP patients varied by age group, showed specific changes in diversity, and were correlated with antiplatelet antibodies. IgG levels were significantly positively correlated with Bacteroides (P<0.01).

Conclusions

The gut microbiota of children with ITP are imbalanced, as shown by the increase in Bacteroidetes, which was positively correlated with IgG. Thus gut microbiota may contribute to ITP pathogenesis via IgG.

Clinical Trial Registration

The clinical trial were registered and approved by the Institutional Review Committee of The Affiliated Huaian No.1 People's Hospital of Nanjing Medical University. Ethics number KY-2023-106-01.

Sustained response off treatment in eltrombopag for children with persistent/chronic primary immune thrombocytopenia: A multicentre observational retrospective study in China

Eltrombopag (ELT) is effective and safe in adult persistent/chronic immune thrombocytopenia (p/cITP); a proportion could achieve a sustained response off treatment (SRoT); however, data on children are lacking. We attempted to analyse SRoT of ELT in children with p/cITP in this study. A multicentre retrospective observational study was performed in November 2022 for children with p/cITP who used ELT alone for >2 months between January 2017 and November 2021. Clinical data of pre-, during and post-ELT were collected. SRoT was defined as maintaining a platelet count of ≥30 × 10⁹ /L without rescue therapy for at least 6 months off ELT. There were 143 patients enrolled; 69.2% (99/143) achieved an overall response of 43.3% and 25.9% achieved complete response (CR) and response (R). Among the 35 patients analysed from whom ELT was withdrawn, 71.4% (25/35) showed SRoT after discontinuing ELT without additional ITP therapy, with a median follow-up of 0.94 (range, 0.53-3.8) years, equal to 17.5% (25/143) in all patients treated with ELT. Compared with the patients with relapse (n = 10), the SRoT patients (n = 25) had a higher rate of CR (80% [20/25] vs. 40% [4/10]), shorter interval time from initiation to taper (6.4 months vs. 9.4 months), longer time from taper to withdrawal (1.1 years vs. 0.3 years) and a longer duration of ELT treatment (1.6 years vs. 0.5 years) with p < 0.05. Patients who achieved CR could attain SRoT more easily (p = 0.02). ELT had a response in 69.2% of children with p/cITP and 17.5% of them attained SRoT with good tolerance. The patients who achieved CR and began ELT treatment as early as possible, with a longer treatment duration and slower tapering, had a higher probability of SRoT.