Should we consider caplacizumab as routine treatment for acute thrombotic thrombocytopenic purpura? An expert perspective on the pros and cons

INTRODUCTION

Immune thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening disorder. Caplacizumab has been the latest drug incorporated into the initial treatment of acute episodes, allowing for faster platelet recovery and a decrease in refractoriness, exacerbation, thromboembolic events, and mortality. However, caplacizumab is also associated with a bleeding risk and higher treatment costs, which prevent many centers from using it universally.

AREAS COVERED

Studies that included iTTP and/or caplacizumab to date were selected for this review using PubMed and MEDLINE platforms. We describe outcomes in the pre-caplacizumab era and after it, highlighting the benefits and risks of its use early in frontline, and also pointing out special situations that require careful management.

EXPERT OPINION

It is clear that the availability of caplacizumab has significantly and favorably impacted the management of iTTP patients. Whether this improvement is cost-effective still remains uncertain, and data on long-term sequelae and different healthcare systems will help to clarify this point. In addition, evidence of the bleeding/thrombotic risk of iTTP patients under this drug needs to be better addressed in future studies.

Spanish registry of thrombotic thrombocytopenic purpura (REPTT): Data evidence and new developments

Immuno Thrombotic thrombocytopenic purpura (iTTP) is a rare and potentially fatal disorder characterized by systemic microvascular thrombosis because of a severe deficiency of ADAMTS13. It is difficult to generate knowledge about TTP because of its low incidence and the lack of clinical trials. Most of the evidence on diagnosis, treatment, and prognosis has been generated from real-world data registries. In 2004, the Spanish Apheresis Group (GEA) implemented the Spanish registry of TTP (REPTT) with 438 patients suffering 684 acute episodes in 53 hospitals up to January 2022. REPTT has studied several aspects of TTP in Spain. The iTTP incidence in Spain our country is 2.67 (95 % CI 1.90-3.45) and the prevalence is 21.44 (95 % CI % 19.10-23.73) patients per million inhabitants. The refractoriness incidence is 4.8 % and exacerbation incidence was 8.4 %, with a median of follow-up of 131.5 months (IQR: 14-178 months). In a 2018 review, the mortality in the first episode due to TTP was 7.8 %. We have also found that de novo episodes require fewer PEX procedures than relapses. Since June 2023, REPTT will involve Spain and Portugal, with a recommended sampling protocol and new variables to improve the neurological, vascular and quality of life evaluation of these patients. The main strength of this project will be the involvement of a combined population of more than 57 million inhabitants, which implies an annual incidence of close to 180 acute episodes per year. This will allow us to provide better answers to questions like treatment efficacy, associated morbidity and mortality, and the possible neurocognitive and cardiac sequelae.

An update on the pathogenesis and diagnosis of thrombotic thrombocytopenic purpura

INTRODUCTION

Severe ADAMTS13 deficiency defines thrombotic thrombocytopenic purpura (TTP). ADAMTS13 is responsible for VWF cleavage. In the absence of this enzyme, widespread thrombi formation occurs, causing microangiopathic anemia and thrombocytopenia and leading to ischemic organ injury. Understanding ADAMTS13 function is crucial to diagnose and manage TTP, both in the immune and hereditary forms.

AREAS COVERED

The role of ADAMTS13 in coagulation homeostasis and the consequences of its deficiency are detailed. Other factors that modulate the consequences of ADAMTS13 deficiency are explained, such as complement system activation, genetic predisposition, or the presence of an inflammatory status. Clinical suspicion of TTP is crucial to start prompt treatment and avoid mortality and sequelae. Available techniques to diagnose this deficiency and detect autoantibodies or gene mutations are presented, as they have become faster and more available in recent years.

EXPERT OPINION

A better knowledge of TTP pathophysiology is leading to an improvement in diagnosis and follow-up, as well as a customized treatment in patients with TTP. This scenario is necessary to define the role of new targeted therapies already available or coming soon and the need to better diagnose and monitor at the molecular level the evolution of the disease.

Recommendations for the diagnosis and treatment of patients with thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy (TMA) characterized by the development of microangiopathic haemolytic anaemia, thrombocytopenia, and ischaemic organ dysfunction associated with ADAMTS13 levels lower than 10% in most cases. Recently there have been numerous advances in the field of PTT, new, rapid and accessible techniques capable of quantifying ADAMTS13 activity and inhibitors. The massive sequencing systems facilitate the identification of polymorphisms in the ADAMTS13 gene. In addition, new drugs such as caplacizumab have appeared and relapse prevention strategies are being proposed with the use of rituximab. The existence of TTP patient registries allow a deeper understanding of this disease but the great variability in the diagnosis and treatment makes it necessary to elaborate guidelines that homogenize terminology and clinical practice. The recommendations set out in this document were prepared following the AGREE methodology. The research questions were formulated according to the PICO format. A search of the literature published during the last 10 years was carried out. The recommendations were established by consensus among the entire group, specifying the existing strengths and limitations according to the level of evidence obtained. In conclusion, this document contains recommendations on the management, diagnosis, and treatment of TTP with the ultimate objective of developing guidelines based on the evidence published to date that allow healthcare professionals to optimize TTP treatment.

Clinical grade production of IL-15 stimulated NK cells for early infusion in adult AML patients undergoing haploidentical stem cell transplantation with post-transplant cyclophosphamide

BACKGROUND

Allogeneic stem cell transplantation is the treatment of choice for acute myeloid leukemia (AML) patients. Unmanipulated haploidentical transplantation (Haplo-HSCT) is commonly used for those AML patients who need a timely transplant and do not have a suitable matched donor, but relapse rates are still high, and improvements are needed. Adoptive immunotherapy using natural killer cells (NK cells) could be a promising tool to improved Haplo-HSCT but, to date, no optimal infusion and manufacturing protocols have been developed.

STUDY DESIGN AND METHODS

In this study, we describe a quick and reproducible protocol for clinical-grade production of haploidentical donor NK cells using double immunomagnetic depletion and enrichment protocol and overnight IL-15 stimulation.

RESULTS

Thus, we have obtained 8 viable and functional NK cell products that have been safely infused to five AML patients undergoing unmanipulated Haplo-HSCT.

DISCUSSION

Our results demonstrate the safety and feasibility of manufactured NK IL15 cells obtained from an adult allogeneic donor in the setting of haploidentical transplantation for AML patients.

Incorporating genetic and clinical data into the prediction of thromboembolism risk in patients with lymphoma

Background

The incorporation of genetic variables into risk scores for predicting venous thromboembolic events (VTE) could improve their capacity to identify those patients for whom thromboprophylaxis would be most beneficial. Proof‐of‐concept of this is provided by the TiC‐ONCO score for predicting the risk of VTE in patients with solid tumours. Our aim was to develop a similarly improved tool—the TiC‐LYMPHO score—for predicting VTE in patients with lymphoma.

Methods

In a retrospective observational study of 208 patients with lymphoma, 31 (14.9%) were found to have experienced an episode of VTE either at the time of diagnosis or over the next 6 months. Clinical variables associated with VTE, determined via logistic regression analysis, plus the same genetic variables included in the TiC‐ONCO score, were used to build the TiC‐LYMPHO score algorithm. The sensitivity, specificity, predictive values and AUC of the TiC‐LYMPHO, the Khorana and ThroLy scores were compared in the same population.

Results

The TiC‐LYMPHO score showed a significantly higher AUC, sensitivity and NPV (0.783, 95.35% and 97.98% respectively) than the other scores. The ThroLy score showed a significantly higher specificity (96.43% vs. 54.49%; p < 0.0001) and PPV (37.50% vs. 26.36%; p = 0.0147) than the TiC‐LYMPHO score, whereas its AUC, sensitivity and NPV were significantly lower (0.579, 19.35% and 86.48%, respectively).

Conclusion

These results show that by incorporating genetic and clinical data into VTE risk assessment, the TiC‐LYMPHO score can categorize patients with lymphoma better in terms of their risk of VTE and allow individualized thromboprophylaxis to be prescribed.

Best practices and recommendations for drug regimens and plasma exchange for immune thrombotic thrombocytopenic purpura

INTRODUCTION

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ injury. TTP pathophysiology is based on a severe ADAMTS13 deficiency, and is a medical emergency with fatal outcome if appropriate treatment is not initiated promptly.

AREAS COVERED

Authors will review the best options currently available to minimize mortality, prevent relapses, and obtain the best clinical response in patients with immune TTP (iTTP). Available bibliography about iTTP treatment has been searched in Library's MEDLINE/PubMed database from January 1990 until April 2021.

EXPERT OPINION

The generalized use of plasma exchange marked a paradigm in the management of iTTP. In recent years, strenuous efforts have been done for a better understanding of the pathophysiology of this disease, improve diagnosis, optimize treatment, reduce mortality, and prevent recurrences. The administration of front-line rituximab and, more recently, the availability of caplacizumab, the first targeted therapy for iTTP, have been steps toward a further reduction in early mortality and for the prevention of relapses.

COVID-19 coagulopathy: An in-depth analysis of the coagulation system

Background

Abnormal coagulation parameters have been reported in COVID‐19‐infected patients. Although the underlying mechanism of COVID‐19 coagulopathy remains unknown, it has been suggested to be a form of disseminated intravascular coagulation (DIC).

Objectives

The aim of our study was to analyze the coagulation parameters of patients with COVID‐19, determine whether coagulation factors consumption occurs and identify potential prognostic biomarkers of the disease.

Patients/Methods

Blood samples from hospitalized patients with COVID‐19 pneumonia were collected. We performed basic coagulation tests and quantification of coagulation factors and physiological inhibitor proteins. Laboratory data were compared with clinical data and outcomes.

Results

The study involved 206 patients (63.6% male). D‐dimer was particularly elevated (median 450 ng/mL; IQR 222.5‐957.3). Free protein S levels were below the normal range (median 56.6%; IQR: 43.6‐68.9), and factor VIII showed an increasing trend (median 173.4%; IQR: 144.1‐214.9). However, all coagulation factors were within normal limits. We found no correlation between abnormal coagulation parameters and thrombosis, except for higher D‐dimer (HR 1.99; 95% CI 1.3‐3.1; P = .002).

Conclusions

COVID‐19 is associated with coagulopathy that correlates with poor prognosis. However, we did not demonstrate a consumption of coagulation factors, as seen in DIC.