The use of obinutuzumab and ofatumumab in the treatment of immune thrombotic thrombocytopenic purpura.

Rituximab, an anti-CD20 monoclonal antibody, can be used to treat immune thrombotic thrombocytopenic purpura (iTTP) during acute presentation or disease relapse. Undesirable side-effects include severe hypersensitivity reactions, particularly anaphylaxis and rituximab-induced serum sickness, with a minority not maintaining a response to treatment. Alternative humanised anti-CD20 treatments, obinutuzumab and ofatumumab, have been used. A review of the UK TTP Registry showed 15 patients received these drugs over 26 treatment episodes (eight obinutuzumab and 18 ofatumumab). Indications for alternative anti-CD20 treatment were severe infusion-related reactions, acute rituximab-induced serum sickness and a short duration of disease remission. All patients achieved disease remission (ADAMTS13 [A disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13] activity ≥30 iu/dl) after a median 15 days and 92% of episodes achieved complete remission (≥60 iu/dl). Seven patients required further treatment for disease relapse with a median relapse-free survival of 17.4 months. All patients continued to respond to re-treatment with the preceding drug when relapse occurred. There were four adverse events in 26 treatment episodes (15%) - two infections and two infusion reactions. These results suggest that obinutuzumab and ofatumumab may be considered as an alternative option to rituximab in the treatment of iTTP with a comparable safety profile, absence of significant hypersensitivity reactions and sustained normalisation of ADAMTS13.

Refractory immune TTP following Pfizer-BioNTech COVID-19 vaccine successfully salvaged with caplacizumab.

Immune thrombotic thrombocytopenic purpura (iTTP) is a life-threatening thrombotic microangiopathy caused by antibodies against ADAMTS13. We report a young, healthy female who developed hematuria, vomiting, and hematemesis 3 weeks after her first dose of Pfizer Bio-NTech COVID-19 vaccine. Investigations confirmed iTTP with undetectable ADAMTS13 activity and a positive antibody assay. Despite initial response to standard treatment with plasma exchange and corticosteroids, she had an acute deterioration of her TTP with neurological and cardiac involvement. Fortunately, she then had prompt response to rituximab and emergently obtained caplacizumab and is now in remission. Although most cases of iTTP are of unknown etiology, we cannot exclude that her almost fatal iTTP episode was triggered by the Pfizer-BioNTech COVID-19 vaccine. This case also highlights the ability of caplacizumab to quickly halt disseminated thrombus formation in refractory TTP.

Thrombotic thrombocytopenic purpura after ChAdOx1 nCoV-19 vaccine.

A 50-year-old Indian woman presented with acute dysphasia, left upper limb numbness and thrombocytopenia 12 days after receiving the ChAdOx1 nCoV-19 vaccine (AstraZeneca/Vaxzevria). MRI of the brain was unremarkable. Microangiopathic haemolytic anaemia with thrombocytopenia was noted on her peripheral blood film. A diagnosis of thrombotic thrombocytopenic purpura (TTP) was confirmed through the findings of absent ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity and markedly raised titre of ADAMTS13 autoantibodies. Prompt treatment with plasma exchange, adjunctive steroids and rituximab was commenced. A remission of TTP was achieved and she was discharged 3 weeks after admission. While other immune-mediated conditions have been documented after receipt of the vaccine, this report highlights the first case of immune-mediated TTP diagnosed after administration of the ChAdOx1 nCoV-19 vaccine.

Successful Treatment of Klebsiella pneumoniae NDM Sepsis and Intestinal Decolonization with Ceftazidime/Avibactam Plus Aztreonam Combination in a Patient with TTP Complicated by SARSCoV-2 Nosocomial Infection.

Carbapenem-resistant Enterobacteriaceae (CRE) are a serious public health threat. Infections due to these organisms are associated with significant morbidity and mortality. Among them, metallo-ß-lactamases (MBLs)-producing Klebsiella pneumoniae are of global concern today. The ceftazidime/avibactam combination and the ceftazidime/avibactam + aztreonam combination currently represent the most promising antibiotic strategies to stave off these kinds of infections. We describe the case of a patient affected by thrombotic thrombocytopenic purpura (TTP) admitted in our ICU after developing a hospital-acquired SarsCoV2 interstitial pneumonia during his stay in the hematology department. His medical conditions during his ICU stay were further complicated by a K. Pneumoniae NDM sepsis. To our knowledge, the patient had no risk factors for multidrug-resistant bacteria exposure or contamination during his stay in the hematology department. During his stay in the ICU, we treated the sepsis with a combination therapy of ceftazidime/avibactam + aztreonam. The therapy solved his septic state, allowing for a progressive improvement in his general condition. Moreover, we noticed that the negativization of the hemocultures was also associated to a decontamination of his known rectal colonization. The ceftazidime/avibactam + aztreonam treatment could not only be a valid therapeutic option for these kinds of infections, but it could also be considered as a useful tool in selected patients' intestinal decolonizations.

Clinical Characteristics and Pharmacological Management of COVID-19 Vaccine-Induced Immune Thrombotic Thrombocytopenia With Cerebral Venous Sinus Thrombosis: A Review.

Importance: The COVID-19 pandemic saw one of the fastest developments of vaccines in an effort to combat an out-of-control pandemic. The 2 most common COVID-19 vaccine platforms currently in use, messenger RNA (mRNA) and adenovirus vector, were developed on the basis of previous research in use of this technology. Postauthorization surveillance of COVID-19 vaccines has identified safety signals, including unusual cases of thrombocytopenia with thrombosis reported in recipients of adenoviral vector vaccines. One of the devastating manifestations of this syndrome, termed vaccine-induced immune thrombotic thrombocytopenia (VITT), is cerebral venous sinus thrombosis (CVST). This review summarizes the current evidence and indications regarding biology, clinical characteristics, and pharmacological management of VITT with CVST. Observations: VITT appears to be similar to heparin-induced thrombocytopenia (HIT), with both disorders associated with thrombocytopenia, thrombosis, and presence of autoantibodies to platelet factor 4 (PF4). Unlike VITT, HIT is triggered by recent exposure to heparin. Owing to similarities between these 2 conditions and lack of high-quality evidence, interim recommendations suggest avoiding heparin and heparin analogues in patients with VITT. Based on initial reports, female sex and age younger than 60 years were identified as possible risk factors for VITT. Treatment consists of therapeutic anticoagulation with nonheparin anticoagulants and prevention of formation of autoantibody-PF4 complexes, the latter being achieved by administration of high-dose intravenous immunoglobin (IVIG). Steroids, which can theoretically inhibit the production of new antibodies, have been used in combination with IVIG. In severe cases, plasma exchange should be used for clearing autoantibodies. Monoclonal antibodies, such as rituximab and eculizumab, can be considered when other therapies fail. Routine platelet transfusions, aspirin, and warfarin should be avoided because of the possibility of worsening thrombosis and magnifying bleeding risk. Conclusions and Relevance: Adverse events like VITT, while uncommon, have been described despite vaccination remaining the most essential component in the fight against the COVID-19 pandemic. While it seems logical to consider the use of types of vaccines (eg, mRNA-based administration) in individuals at high risk, treatment should consist of therapeutic anticoagulation mostly with nonheparin products and IVIG.