Drs Picod and Coppo noted that a recombinant human ADAMTS13 (rhADAMTS13) has also been developed and is now being tested in patients with congenital TTP. Preliminary data have shown this agent had effectiveness and was well tolerated. A phase 3 trial assessing the efficacy of rhADAMTS13 prophylaxis to prevent acute episodes in congenital TTP is currently under way (ClinicalTrials.gov Identifier: NCT03393975). “This therapeutic agent could also show efficacy in iTTP,” wrote the authors.

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Clinical Perspectives and Future Directions

Joseph E Kiss, MD, professor of medicine in the division of hematology and oncology at the University of Pittsburgh in Pennsylvania, said new targeted approaches offer a great deal of promise for lowering morbidity and mortality in patients with iTTP. “New drugs such as caplacizumab have propelled us into an era of targeted therapy that directly blocks the formation of microthrombi in patients with iTTP in contrast to the current therapy of TPE, which is efficacious but takes time to work,” Dr Kiss told Hematology Advisor. “The platelet-Von Willebrand factor blockade [caused by caplacizumab] occurs immediately after the drug is given. This halts the thrombotic process and is potentially life-saving for patients with critical ischemia to organs such as the brain, the heart, and the abdominal viscera, which are often affected in patients with this disease.”

Raymond Adili, MD, research assistant professor in the department of pharmacology at the University of Michigan in Ann Arbor, said the treatment landscape for both congenital TTP and acquired TTP may be changing significantly over the next few years. “In terms of new treatments, there are a number of approaches under development,” Dr Adili said in an interview with Hematology Advisor. “Hematologists are just starting to use caplacizumab and are reporting it reduces overall costs. It is safe and causes minimal bleeding.”

Adding caplacizumab to the current armamentarium may shorten the course of the disease or the number of days a patient is in the hospital. George M Rodgers, MD, PhD, professor of medicine in hematology and hematologic malignancies at the University of Utah in Salt Lake City, said that conversations with patients can now be more fine-tuned. “[Using caplacizumab] is going to improve mortality. It gives many more patients a much better fighting chance who otherwise would not do very well,” said Dr Rodgers. “Approximately 10% to 20% of patients with iTTP have refractory disease and don’t survive. Now, many of these patients will be salvageable.”

References

1.     Picod A, Coppo P. When targeted therapies alleviate the burden of TPE: The example of immune-mediated TTP [published online April 19, 2019]. Transfus Apher Sci. doi:10.1016/j.transci.2019.04.012

  1. Scully M, Cataland SR, Peyvandi F, et al. Caplacizumab treatment for acquired thrombotic thrombocytopenic purpura [published online January 24, 2019]. N Engl J Med. doi:10.1056/NEJMoa1806311