Romiplostim for chemotherapy‐induced thrombocytopenia: Efficacy and safety of extended use

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.

Use of romiplostim for antineoplastic therapy-induced thrombocytopenia in gynecologic and breast cancers

Objective

Romiplostim is used to treat chemotherapy-induced thrombocytopenia in a variety of tumor types; however, few studies have examined its use in breast and gynecologic cancers. We evaluated platelet response and durability of response to romiplostim in patients with gynecologic or breast cancer complicated by chemotherapy-induced thrombocytopenia.

Methods

We retrospectively identified 33 patients with gynecologic or breast cancer who received romiplostim between 07/1/2021-07/31/2022 at an academic cancer center.

Results

Thirty-three patients met inclusion criteria; 26 (79 %) had breast cancer, 4 (12 %) had ovarian cancer, and 3 (9 %) had endometrial cancer. Twenty patients (61 %) experienced treatment delays and 12 (36 %) required dose reductions prior to starting romiplostim for chemotherapy-induced thrombocytopenia, with some patients experiencing both. Eleven patients (33 %) did not undergo a dose reduction or delay prior to initiation of romiplostim. Median platelet count prior to romiplostim therapy was 53 k/mcL (range, 40.5-78.8). Median platelet count within 3 weeks following initiation of romiplostim was 147 k/mcL (range, 31-562). Twenty-one patients (64 %) achieved platelet correction within 3 weeks, of whom 10 (48 %) resumed anticancer therapy and maintained platelet levels above 100 k/mcL at 8 weeks. Twelve patients did not achieve platelet correction within 3 weeks of romiplostim initiation; 4 (33 %) required a treatment change secondary to persistent thrombocytopenia, 3 (25 %) required a treatment dose reduction, 3 (25 %) were deemed too ill to continue therapy, and 2 (17 %) required a treatment delay.

Conclusions

Romiplostim facilitated the resumption of anticancer therapy in 64 % of patients with gynecologic or breast cancer complicated by chemotherapy-induced thrombocytopenia.

Endovascular treatment of renal vein thrombosis in a young patient with lung transplant

Spontaneous renal vein thrombosis is a rare entity. A 28-year-old woman with a history of a double-lung transplant was admitted with flank pain and found to have acute kidney injury. A magnetic resonance venogram demonstrated isolated left renal vein thrombosis with extension into the inferior vena cava. Initial management with therapeutic anticoagulation and hydration was unsuccessful. Thus, pharmacochemical thrombectomy was performed. A temporary suprarenal inferior vena cava filter was placed for intraoperative pulmonary prophylaxis. The patient's renal function returned to baseline and remained normal 13 months later. Early incorporation of percutaneous pharmacomechanical thrombectomy can improve renal function when medical therapy alone is unsuccessful.

Antithrombotic and hemostatic stewardship: Evaluation of romiplostim for treatment of thrombocytopenia at a large academic medical center

Romiplostim is indicated for immune thrombocytopenia (ITP), though is often used off-label for other indications such as chemotherapy-induced thrombocytopenia (CIT) and thrombocytopenia post hematopoietic stem cell transplantation (HSCT). Although romiplostim is FDA approved at a starting dose of 1 mcg/kg, it is often initiated at 2-4 mcg/kg depending on the severity of thrombocytopenia in clinical practice. Given the limited data, but interest in higher doses of romiplostim for indications other than ITP, we aimed to assess our inpatient romiplostim utilization at NYU Langone Health.This was a single-center, retrospective review of 84 adult patients from January 2019 to July 2021. The top three indications were ITP (51, 60.7%), CIT (13, 15.5%), and HSCT (10, 11.9%). The median initial romiplostim dose was 3.8 mcg/kg (range, 0.9-10.8). 51% of patients achieved a platelet count of ≥50 × 109/L by the end of week 1 of therapy. For patients achieving goal platelets by the end of week 1, the median dose of romiplostim was 2.4 mcg/kg (range, 0.9-10.8). There was 1 episode of thrombosis and 1 episode of stroke.We found that higher than FDA-recommended initial doses should be considered to achieve a platelet response. It appears to be safe to initiate romiplostim as higher doses, and to increase doses by greater increments than 1 mcg/kg in order to achieve a platelet response. Future prospective studies are needed to confirm the safety and efficacy of romiplostim in off-label indications and should evaluate clinical outcomes such as bleeding and need for transfusions.

Optimal management of chemotherapy-induced thrombocytopenia with thrombopoietin receptor agonists

Chemotherapy-induced thrombocytopenia (CIT) is a common complication of antineoplastic therapy, resulting in antineoplastic therapy dose reductions, treatment delays, treatment discontinuation, and morbid bleeding events. Despite several decades of research into thrombopoietic growth factors in CIT, there are presently no available U.S. FDA- or EMA-approved agents to treat CIT. However, a respectable body of evidence has been published evaluating the thrombopoietin receptor agonists (TPO-RAs) for the management and prevention of CIT in patients with solid tumors, and critical studies are ongoing with the TPO-RAs romiplostim and avatrombopag. When employed in the appropriate patient population and used properly, TPO-RAs can successfully and safely manage CIT for extended periods of time with minimal apparent risks. This comprehensive review discusses the evidence for TPO-RAs in CIT in patients with solid tumors, provides detailed guidance for their use in the clinic, and discusses ongoing essential clinical trials in management of CIT.

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.

Emerging data on thrombopoietin receptor agonists for management of chemotherapy-induced thrombocytopenia

INTRODUCTION

Chemotherapy-induced thrombocytopenia (CIT) is a common complication of cancer treatment, frequently leading to reduced relative dose intensity, and is associated with reduced survival. Given the lack of FDA-approved therapies for CIT, thrombopoietin receptor agonists (TPO-RAs) have received significant attention for treatment and prevention of CIT.

AREAS COVERED

This review will summarize the development of prior agents for treatment of CIT, discuss the existing literature investigating the use of TPO-RAs in CIT primarily in patients with solid tumor malignancies, and offer insights on the future direction of TPO-RAs and other therapeutics for CIT.

EXPERT OPINION

In alignment with NCCN guidelines, we recommend that patients with CIT participate in a clinical trial for consideration of TPO-RA treatment or consider off-label use of romiplostim when participation in clinical trials is not possible. The literature to date supports the use of TPO-RAs for treatment of persistent CIT. Further data is needed to describe the long-term efficacy, safety, and prescribing practices of TPO-RAs in a diverse patient population with a variety of tumor types and chemotherapy regimens in addition to exploring the underlying biology of CIT.