Bidirectional inefficacy or intolerability of thrombopoietin receptor agonists: new data and a concise review

The Clinical Efficacy and Economic Benefits of Recombinant Human Thrombopoietin for the Treatment of Chemotherapy or Chemoradiotherapy-Induced Thrombocytopenia

Even though cytopenia caused by either chemotherapy or radiotherapy is a common complication in cancer patients, chemoradiotherapy remains an essential treatment for the majority of patients. The purpose of this study was to look into the clinical efficacy and cost-effectiveness of recombinant human thrombopoietin (rhTPO) in treating chemo- or chemoradiotherapy-induced grade II, III, and IV thrombocytopenia. From December 2019 to November 2020, 233 lung cancer patients admitted to our hospital with chemotherapy- or chemoradiotherapy-induced thrombocytopenia were enrolled and treated with rhTPO. The study's findings revealed a significant disparity in the use of concurrent chemoradiotherapy in patients with grade II, III, and IV thrombocytopenia. All costs, including rhTPO treatment costs, platelet costs, drug costs, and nondrug costs, tended to rise as the severity of thrombocytopenia increased. In the treatment of chemotherapy or radiotherapy-induced thrombocytopenia, rhTPO has shown good clinical efficacy. In the treatment of grade II thrombocytopenia, rhTPO has a favorable economic evaluation. As a result, early intervention and thrombocytopenia treatment should be provided, which warrants further clinical investigation.

Romiplostim and Eltrombopag in Immune Thrombocytopenia as a Second-Line Treatment

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by platelet count less than 100×10⁹/L and an increased risk of bleeding. The risk of bleeding increases in proportion with the degree of thrombocytopenia. Although several medications are used for primary thrombocytopenia treatment, refractoriness remains a concern. Romiplostim and eltrombopag, two relatively new drugs, have been shown to be successful in ITP treatment after standard treatment failure. The current guidelines recommend their use as a second-line treatment. In this article, we have tried to compare which of these two medications is the best option considering clinical effectiveness, cost-effectiveness, adverse effects, and the possibility of switching between them in case of ineffectiveness. The studies used in this article were found in the PubMed database. All the studies are limited to adults. Based on these studies, both medications seem to be a largely effective, safe option. Romiplostim appears to have slightly fewer adverse effects and higher costs. Switching between thrombopoietin receptor agonists (TRAs) is a successful way to overcome adverse effects and inadequacy according to the currently available literature. We believe that more detailed studies are needed to determine which of these drugs should be considered the first choice, to report long term efficacy and adverse effects, and to determine if treatment guidelines can change regarding the use of TRAs as first-line treatment.

Deciphering predictive factors for choice of thrombopoietin receptor agonist, treatment free responses, and thrombotic events in immune thrombocytopenia

Very few data exist on when a particular thrombopoietin-receptor agonist (TPO-RA) is favored in clinical practice for the treatment of patients with immune thrombocytopenia (ITP), about novel risk factors for vascular events (VE) with these drugs, nor about predictive factors for therapy free responses (TFR). We conducted an observational, retrospective, long-term follow-up multicenter study from November 2016 to January 2018 of 121 adult ITP patients initiating TPO-RA between January 2012 to December 2014. Data reflected that a platelet count ≤25 × 10⁹/l at the time when the TPO-RA was initiated was associated with a 2.8 higher probability of receiving romiplostim vs. eltrombopag (P = 0.010). VE on TPO-RA was related to previous neoplasia in patients over 65 years (50% vs. 2.2%, P < 0.001), and to previous splenectomy in younger patients (100% vs. 33%, P = 0.001). Receiving romiplostim as first TPO-RA with no subsequent TPO-RA switching was associated with a 50% likelihood of TFR after 2.9 years of therapy (3.3 years in chronic ITP patients). These real-world data help deciphering some areas of uncertainty, and offer insight into some of the most relevant challenges of ITP which may help clinicians make appropriate treatment decisions in the management of adult ITP patients with TPO-RA.

Switching thrombopoietin receptor agonist treatments in patients with primary immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is a bleeding disorder that conventionally has been treated with steroids or other immunosuppressive treatments. The introduction of thrombopoietin receptor agonists (TPO-RAs), which increase platelet production, dramatically changed the treatment landscape for ITP by providing patients with well-tolerated, long-term treatment options. Two TPO-RAs, eltrombopag and romiplostim, have been approved in the United States and European Union for the treatment of ITP. Some patients do not benefit from the first TPO-RA they receive, so it is assumed that the alternate TPO-RA would have the same outcome. However, eltrombopag and romiplostim have distinct pharmacodynamic and pharmacokinetic properties and may have different tolerability and efficacy in individual patients with ITP. Published retrospective studies showed that >75% of patients who switched to the alternate TPO-RA maintained or achieved a response with the new treatment. Notably, most patients who switched due to lack of efficacy with the first TPO-RA responded to the alternate TPO-RA, which demonstrates an absence of cross-resistance between the two drugs. Therefore, switching to the alternate TPO-RA if the first TPO-RA fails to demonstrate a response should be considered before the use of a less-preferable option.

Romiplostim for Immune Thrombocytopenia in Neuroblastoma Patients Receiving Chemotherapy

Thrombocytopenia, a serious complication of myelosuppressive chemotherapy in cancer patients, is managed with platelet transfusions until recovery of platelet counts. However, children receiving chemotherapy can rarely develop immune thrombocytopenia (ITP) that is refractory to transfused platelets. This limits the ability to achieve adequate platelet counts and administer further myelosuppressive chemotherapy safely, especially if first-line ITP therapy is ineffective. We report 2 cases of intravenous immunoglobulin refractory ITP in children receiving chemotherapy for high-risk neuroblastoma. ITP was successfully treated with the thrombopoietin-receptor-agonist romiplostim, allowing safe and timely continuation of antineuroblastoma therapies in these high-risk patients.

Efficacy and tolerability of old and new drugs used in the treatment of immune thrombocytopenia: Results from a long-term observation in clinical practice

Background

Many patients with immune thrombocytopenia (ITP) may require special attention and long-term treatment. Little is known on the efficacy and tolerability of the drugs used in practice.

Material and methods

We retrospectively reviewed the results of therapy of 400 patients with chronic ITP. All Patients were treated at our institution between 1996–2016 under consideration of guidelines, general recommendations, and individual aspects, including gender, age, weight, comorbidity, patient’s medical history and bleeding risk.

Results

Treatment was not required in 25% of patients (n = 100) during observation. In treated patients (n = 300), the rate of patients that responded and tolerated treatment with prednisolone was 59% (52/88), with azathioprine 32% (29/90), with eltrombopag 49% (31/63), with romiplostim 59% 27/45, with IVIG (intravenous immunoglobulines) 75% (94/126), with anti-D 37% (19/52) and with dexamethasone 60% (25/42) patients. Eighteen treated patients (6%) entered sustained remission after treatment with various drugs. Twenty-six patients underwent splenectomy (Splx) resulting in sustained remission in 15 cases (60%). Only two patients remained refractory to Splx and to all used drugs.

Discussion

None of the currently available drugs used in the treatment of ITP are invariably safe and effective. Responses, the duration of response, intolerability, and the course of disease are unpredictable. Although the treatment of ITP has considerably improved in the recent years, the currently available drugs may rarely cure affected patients. The need for safe and effective therapy in ITP is evident. Optimal treatment decisions for each patient remains a challenge in many cases.