During Tuesday’s State-of-the-Art session, Spero Cataland, M.D. presented the advances made in the management of thrombotic thrombocytopenic purpura (TTP), immune-mediated TTP (iTTP), and congenital TTP (cTTP), and described the role of ADAMTS13 in this condition:
- In acquired TTP, caplacizumab significantly reduced the time to response compared with placebo.
- In cTTP, a phase 1 trial showed that recombinant ADAMTS13 (BAX 930) was well tolerated with no serious adverse events and no anti-ADAMTS13 binding or neutralizing antibodies.
- Depression and cognitive impairment significantly impact TTP patients’ quality of life.
- Novel therapies will require novel monitoring.
At this session, Dr. Cataland described the role of ADAMTS13 in TTP and presented two important TTP clinical trials. The first trial assessed cyclosporine and plasma exchange (PEX) vs. prednisone and PEX for the treatment of patients with acute TTP, and showed that the exacerbation rate was not significantly different between the two treatments within the first 30 days. The second was a phase 2 study of ALX-0081 (caplacizumab) vs. placebo for the treatment of acquired TTP, and found that caplacizumab significantly reduced the time to response (39% reduction in median time to response; event rate ratio, 2.20; 95% CI, 1.28 to 3.78; P = 0.005). A 12-month post hoc evaluation of ADAMTS13 activity in relation to exacerbation or relapse showed that 3 caplacizumab-treated patients had an exacerbation compared to 11 in the placebo arm. In the caplacizumab-treated subjects, the ADAMTS13 activity was still <10% in 2 of 3 patients; in the 11 patients in the placebo group, baseline ADAMTS13 activity was <10% in 10/11 subjects.
Emerging data for novel therapies in the management of cTTP and iTTP were also presented. These included a phase 1 study in cTTP which showed that a recombinant ADAMTS13 (BAX 930) was well tolerated with no serious adverse events, and no anti-ADAMTS13 binding or neutralizing antibodies. Cataland also presented data showing the significance of depression and cognitive impairment and their impact on TTP patients’ quality of life.
Overall, there are several exciting, novel therapies (namely, caplacizumab and BAX 930) for the treatment of iTTP and cTTP, but a better understanding of their optimal use is required. With these novel therapies comes the question of whether traditional monitoring methods of the efficacy and the acute and chronic complications are relevant or if novel methods will be necessary. It will be critical to continue to monitor long-term congenital, immune-mediated complications.