Systematic literature review and meta-analysis on use of Thrombopoietic agents for chemotherapy-induced thrombocytopenia

Observation on the efficacy of TPO receptor agonists and platelet transfusion in chemotherapy-induced thrombocytopenia in malignant tumors

OBJECTIVE

To observe the clinical efficacy of TPO receptor agonists and platelet transfusion in chemotherapy-induced thrombocytopenia in malignant tumors.

METHODS

Clinical data from 120 patients with malignant tumors who developed thrombocytopenia following chemotherapy at our hospital were retrospectively collected and randomly divided into three groups: A, B, and C, with 40 patients in each group. Group A was treated with a TPO receptor agonist (avatrombopag), group B received autologous platelet transfusion, and group C received a combination of both treatments. The clinical efficacy of the three groups was compared, including platelet levels at different time points during treatment, platelet recovery time (time to reach < 50 × 109/L, ≥ 75-100 × 109/L, and ≥ 100 × 109/L), changes in serum cytokine levels (PF4, TPO, vWF) before and after treatment, and fluctuations in coagulation function indicators (APTT, PT, FIB) before and after treatment to analyze the effectiveness of each treatment regimen.

RESULTS

About clinical efficacy, the effectiveness in group A was comparable to that in group B (P > 0.05), while the effective rate in group C was significantly higher than that in groups A and B (P < 0.05). Regarding platelet counts, repeated measures analysis of variance showed significant differences in the time effect, group effect, and interaction effect for platelet counts (PLT) among the three groups (P < 0.05). Concerning platelet recovery time, the time to reach PLT < 50 × 109/L, the time to recover to 75-100 × 109/L, and the time to recover to ≥ 100 × 109/L were similar in groups A and B (P > 0.05). However, the time for these parameters in group C was significantly shorter than in groups A and B (P < 0.05). In terms of changes in platelet parameters, post-treatment levels of PF4, TPO, and vWF in all three groups were significantly higher than pre-treatment levels. The PF4, TPO, and vWF levels in groups A and B were similar (P > 0.05), whereas group C had significantly higher levels compared to groups A and B (P < 0.05). Regarding coagulation indices, post-treatment levels of APTT and PT decreased, while FIB levels increased in all three groups (P < 0.05). There were no significant differences in APTT and FIB levels between groups A and B (P > 0.05). However, group C had significantly lower APTT and higher FIB levels compared to groups A and B (P < 0.05). There were no significant differences in PT levels among the three groups post-treatment (P > 0.05).

CONCLUSION

Autologous platelet transfusion and TPO receptor agonists are effective clinical methods for treating chemotherapy-induced thrombocytopenia. The combined use of both treatments yields better therapeutic results.

Application of thrombopoietic agents in cancer therapy-induced thrombocytopenia: A comprehensive review

Cancer therapy-induced thrombocytopenia (CT-IT) is one of the most common hematological toxicities of anti-cancer therapy, often leading to treatment dose reduced, postponed, or treatment plans altered or even discontinued. Thrombopoietin (TPO) is the only key regulatory factor in platelet production, and TPO receptor is considered an ideal target for the treatment of thrombocytopenia. Thrombopoietic agents, including recombinant human thrombopoietin (rhTPO) and thrombopoietin receptor agonists (TPO-RAs), bind to different regions of the TPO receptor, activating downstream signaling pathways to increase platelet levels. In recent years, numerous studies have demonstrated the effectiveness of thrombopoietic agents in the management of CT-IT. These agents can reduce bleeding risk, decrease platelet transfusions, and maintain relative dose intensity (RDI) of anti-cancer treatments. This article provides a review of the current progress in the application of thrombopoietic agents for CT-IT management.

Role of thrombopoietin receptor agonists in chemotherapy-induced thrombocytopenia: A meta-analysis

INTRODUCTION

Chemotherapy-induced thrombocytopenia (CIT) is a significant challenge in cancer treatment, often leading to dose reductions and reduced number of cycles. The limited effectiveness of platelet transfusions in managing CIT highlights the need for alternative treatments. Thrombopoietin receptor agonists (TPO-RA), including romiplostim, eltrombopag and avatrombopag, have shown potential in increasing platelet counts in CIT patients, necessitating a comprehensive analysis of their efficacy.

METHODS

This meta-analysis followed the Preferred Reporting Items for Systemic Reviews and Meta-analysis guidelines, searching Ovid databases up to 5 October 2023. The primary metric of interest was platelet count changes post-TPO-RA administration in CIT patients.

RESULTS

From the initial 867 studies obtained, 7 studies were selected based on the inclusion criteria. The analysis included 348 patients. A significant association was found between TPO-RA administration and platelet count increase, with a combined-effect increase of 69.52 ± 2.24 × 109/l. Subgroup analysis based on Romiplostim use suggested an increase of approximately 70.11 ± 39.07 × 109/l, while non-Romiplostim TPO-RAs showcased an increase of about 68.09 ± 82.58 × 109/l.

CONCLUSIONS

The meta-analysis demonstrates the effectiveness of TPO-RAs in managing CIT. Further research comparing platelet increases across standardised TPO-RA regimens is recommended to refine treatment strategies. This analysis provides valuable insights for clinicians in tailoring CIT treatment using TPO-RAs.

Romiplostim in chemotherapy-induced thrombocytopenia: A review of the literature

Chemotherapy-induced thrombocytopenia (CIT) is a common challenge of cancer therapy and can lead to chemotherapy dose reduction, delay, and/or discontinuation, affecting relative dose intensity, and possibly adversely impacting cancer care. Besides changing anticancer regimens, standard management of CIT has been limited to platelet transfusions and supportive care. Use of the thrombopoietin receptor agonist romiplostim, already approved for use in immune thrombocytopenia, has shown promising signs of efficacy in CIT. In a phase 2 prospective randomized study of solid tumor patients with platelet counts <100 × 109/L for ≥4 weeks due to CIT, weekly romiplostim corrected the platelet count to >100 × 109/L in 93% (14/15) of patients within 3 weeks versus 12.5% (1/8) of untreated patients (p < 0.001). Including patients treated with romiplostim in an additional single-arm cohort, 85% (44/52) of all romiplostim-treated patients responded with platelet count correction within 3 weeks. Several retrospective studies of CIT have also shown responses to weekly romiplostim, with the largest study finding that poor response to romiplostim was predicted by tumor invasion of the bone marrow (odds ratio, 0.029; 95% CI: 0.0046-0.18; p < 0.001), prior pelvic irradiation (odds ratio, 0.078; 95% CI: 0.0062-0.98; p = 0.048), and prior temozolomide treatment (odds ratio 0.24; 95% CI: 0.061-0.96; p = 0.043). Elsewhere, lower baseline TPO levels were predictive of romiplostim response (p = 0.036). No new safety signals have emerged from romiplostim CIT studies. Recent treatment guidelines, including those from the National Comprehensive Cancer Network, now support consideration of romiplostim use in CIT. Data are expected from two ongoing phase 3 romiplostim CIT trials.

Hetrombopag for the management of chemotherapy-induced thrombocytopenia in patients with advanced solid tumors: a multicenter, randomized, double-blind, placebo-controlled, phase II study

Background

Chemotherapy-induced thrombocytopenia (CIT) increases the risk of bleeding, necessitates chemotherapy dose reductions and delays, and negatively impacts prognosis.

Objectives

This study aimed to evaluate the efficacy and safety of hetrombopag for the management of CIT in patients with advanced solid tumors.

Design

A multicenter, randomized, double-blind, placebo-controlled, phase II study.

Methods

Patients with advanced solid tumors who experienced a chemotherapy delay of ⩾7 days due to thrombocytopenia (platelet count <75 × 109/L) were randomly assigned (1:1) to receive oral hetrombopag at an initial dose of 7.5 mg once daily or a matching placebo. The primary endpoint was the proportion of treatment responders, defined as patients resuming chemotherapy within 14 days (platelet count ⩾100 × 109/L) and not requiring a chemotherapy dose reduction of ⩾15% or a delay of ⩾4 days or rescue therapy for two consecutive cycles.

Results

Between 9 October 2021 and 5 May 2022, 60 patients were randomized, with 59 receiving ⩾1 dose of assigned treatment (hetrombopag/placebo arm, n = 28/31). The proportion of treatment responders was significantly higher in the hetrombopag arm than in the placebo arm [60.7% (17/28) versus 12.9% (4/31); difference of proportion: 47.6% (95% confidence interval (CI): 26.0-69.3); odds ratio = 10.44 (95% CI: 2.82-38.65); p value (nominal) based on the Cochran-Mantel-Haenszel: <0.001)]. During the double-blind treatment period, grade 3 or higher adverse events (AEs) occurred in 35.7% (10/28) of patients with hetrombopag and 38.7% (12/31) of patients on placebo. The most common grade 3 or higher AEs were decreased neutrophil count [35.7% (10/28) versus 35.5% (11/31)] and decreased white blood cell count [17.9% (5/28) versus 19.4% (6/31)]. Serious AEs were reported in 3.6% (1/28) of patients with hetrombopag and 9.7% (3/31) of patients with placebo.

Conclusion

Hetrombopag is an effective and well-tolerated alternative for managing CIT in patients with solid tumors.

Trial registration

ClinicalTrials.gov identifier: NCT03976882.

A real-world observation on thrombopoietic agents for patients with cancer treatment-induced thrombocytopenia in China: A multicenter, cross-sectional study

BACKGROUND

Studies on various thrombopoietic agents for cancer treatment-induced thrombocytopenia (CTIT) in China are lacking. This study aimed to provide detailed clinical profiles to understand the outcomes and safety of different CTIT treatment regimens.

METHODS

In this retrospective, cross-sectional study, 1664 questionnaires were collected from 33 hospitals between March 1 and July 1, 2021. Patients aged >18 years were enrolled who were diagnosed with CTIT and treated with recombinant interleukin 11 (rhIL-11), recombinant thrombopoietin (rhTPO), or a thrombopoietin receptor agonist (TPO-RA). The outcomes, compliance, and safety of different treatments were analyzed.

RESULTS

Among the 1437 analyzable cases, most patients were treated with either rhTPO alone (49.3%) or rhIL-11 alone (27.0%). The most common combination regimen used was rhTPO and rhIL-11 (10.9%). Platelet transfusions were received by 117 cases (8.1%). In multivariate analysis, rhTPO was associated with a significantly lower proportion of platelet recovery, platelet transfusion, and hospitalization due to chemotherapy-induced thrombocytopenia (CIT) than rhIL-11 alone. No significant difference was observed in the time taken to achieve a platelet count of >100 × 109/L and chemotherapy dose reduction due to CIT among the different thrombopoietic agents. The outcomes of thrombocytopenia in 170 patients who received targeted therapy and/or immunotherapy are also summarized. The results show that the proportion of platelet recovery was similar among the different thrombopoietic agents. No new safety signals related to thrombopoietic agents were observed in this study. A higher proportion of physicians preferred to continue treatment with TPO-RA alone than with rhTPO and rhIL-11.

CONCLUSIONS

This survey provides an overview of CTIT and the application of various thrombopoietic agents throughout China. Comparison of monotherapy with rhIL-11, rhTPO, and TPO-RA requires further randomized clinical trials. The appropriate application for thrombopoietic agents should depend on the pretreatment of platelets, treatment variables, and risk of bleeding.

PLAIN LANGUAGE SUMMARY

To provide an overview of the outcome of cancer treatment-induced thrombocytopenia in China, our cross-sectional study analyzed 1437 cases treated with different thrombopoietic agents. Most of the patients were treated with recombinant interleukin 11 (rhIL-11) and recombinant thrombopoietin (rhTPO). rhTPO was associated with a significantly lower proportion of platelet recovery and platelet transfusion compared with rhIL-11.

Management of chemotherapy-induced thrombocytopenia: guidance from the ISTH Subcommittee on Hemostasis and Malignancy

Thrombocytopenia is a common adverse effect of chemotherapy. The development of chemotherapy-induced thrombocytopenia (CIT) is influenced by cancer type and therapy, occurring in approximately one-third of patients with a solid tumor diagnosis and half of all patients with a hematologic malignancy. CIT may complicate the administration of chemotherapy, leading to therapeutic delays or dose reductions. This guidance document, presented by the International Society on Thrombosis and Haemostasis (ISTH) Subcommittee on Hemostasis and Malignancy, provides a comprehensive summary of the evidence and offers direction on the use of thrombopoietin receptor agonists (TPO-RAs) in various settings of CIT, including solid tumors, acute myeloid leukemia, stem cell transplant, and lymphoma. Studies have shown that TPO-RAs can improve platelet counts in CIT, but the clinical benefits of TPO-RA in terms of reducing bleeding, limiting platelet transfusion, avoiding chemotherapy delay, or dose reduction are uncertain. Further research is needed to optimize the selection of appropriate indications and study design to manage thrombocytopenia following chemotherapy.

Patients Undergoing Systemic Anti-Cancer Therapy Who Require Surgical Intervention: What Surgeons Need to Know

As part of routine cancer care, patients may undergo elective surgery with the aim of long-term cure. Some of these patients will receive systemic anti-cancer therapy (SACT) in the neoadjuvant and adjuvant settings. The majority of patients, usually with locally advanced or metastatic disease, will receive SACT with palliative intent. These treatment options are expanding beyond traditional chemotherapy to include targeted therapies, immunotherapy, hormone therapy, radionuclide therapy and gene therapy. During treatment, some patients will require surgical intervention on an urgent or emergency basis. This narrative review examined the evidence base for SACT-associated surgical risk and the precautions that a surgical team should consider in patients undergoing SACT.

rhTPO Ameliorates Radiation-Induced Long-Term Hematopoietic Stem Cell Injury in Mice

Exposure to medium and high doses of ionizing radiation (IR) can induce long-term bone marrow (BM) suppression. We previously showed that recombinant human thrombopoietin (rhTPO) significantly promotes recovery from hematopoietic-acute radiation syndrome, but its effect on long-term BM suppression remains unknown. C57BL/6 mice were exposed to 6.5 Gy γ-rays of total body irradiation (TBI) at a dose-rate of 63.01 cGy per minute, and the mice were treated with rhTPO (100 μg; intramuscular injection) or vehicle at 2 h after TBI. All mice were killed one or two months after TBI for analysis of peripheral blood cell counts, long-term hematopoietic stem cell (HSC) frequency, and BM-derived clonogenic activity. The HSC self-renewal capacity was analyzed by BM transplantation. The levels of reactive oxygen species (ROS) production and ratios of γH2AX+ and p16, p53, and p21 mRNA in HSCs were measured by flow cytometry and real-time polymerase chain reaction, respectively. Treatment with rhTPO reduced long-term myelosuppression by improving long-term hematopoietic reconstitution (p < 0.05) after transplantation and resting state maintenance of HSCs (p < 0.05). Moreover, rhTPO treatment was associated with a sustained reduction in long-term ROS production, reduction of long-term DNA damage, diminished p53/p21 mRNA expression, and prevention of senescence after TBI. This study suggests rhTPO is an effective agent for treating IR-induced long-term BM injury because it regulates hematopoietic remodeling and HSC cycle disorder through the ROS/p53/p21/p16 pathway long term after IR.

Interactions between Platelets and Tumor Microenvironment Components in Ovarian Cancer and Their Implications for Treatment and Clinical Outcomes

Platelets, the primary operatives of hemostasis that contribute to blood coagulation and wound healing after blood vessel injury, are also involved in pathological conditions, including cancer. Malignancy-associated thrombosis is common in ovarian cancer patients and is associated with poor clinical outcomes. Platelets extravasate into the tumor microenvironment in ovarian cancer and interact with cancer cells and non-cancerous elements. Ovarian cancer cells also activate platelets. The communication between activated platelets, cancer cells, and the tumor microenvironment is via various platelet membrane proteins or mediators released through degranulation or the secretion of microvesicles from platelets. These interactions trigger signaling cascades in tumors that promote ovarian cancer progression, metastasis, and neoangiogenesis. This review discusses how interactions between platelets, cancer cells, cancer stem cells, stromal cells, and the extracellular matrix in the tumor microenvironment influence ovarian cancer progression. It also presents novel potential therapeutic approaches toward this gynecological cancer.

Avatrombopag for the treatment of thrombocytopenia induced by chemotherapy in patients with solid tumors: A multicenter, open-label, single-arm trial

Objective: To explore the effect and safety of avatrombopag for chemotherapy-induced thrombocytopenia (CIT).

Methods: This multicenter, open-label, single-arm trial enrolled CIT patients in eight centers from October 2020 to April 2021. The participants received avatrombopag tablets 60 mg once a day for 5–10 days. The main endpoint was the proportion of patients with platelet count ≥100×10⁹/L or increased by ≥ 50×10⁹/L or increased by ≥ 100% in the cycle after the start of treatment.

Results: Seventy-four participants were enrolled with a mean age of 59.8 ± 11.62.2% were males. The cumulative effective rate (any criteria) was 70.3% at 4 weeks. 42 (56.8%) achieved platelet count ≥100×10⁹/L, 44 (59.5%) increased by ≥ 50×10⁹/L, and 27 (36.5%) increase by ≥ 100% from baseline. The duration of grade III and IV platelet reduction was 4.2 ± 5.3 days. The time of PLT recovery to ≥75×10⁹/L was 9.4 ± 6.6 days. The time of PLT recovery to ≥100×10⁹/L was 10.2 ± 6.4 days. The platelet count nadir was 57.9 ± 45.3×10⁹/L. The most common adverse events were nausea (8.1%), fatigue (5.4%), and abdominal pain (1.4%). There were no cases of fever, headache, or peripheral edema.

Conclusion: Although it was a single-arm trial without a control group, the application of avatrombopag in patients with CIT can increase the platelet count of the patients compared with baseline. Avatrombopag is safe and tolerable.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT04609891?term=04609891&draw=2&rank=1, identifier [NCT04609891]