Data about efficacy and safety of daratumumab in iTTP refractory or intolerant to standard immunosuppressive treatments are scarce. Therefore, the investigators aim at collecting evidence on a larger number of patients through a collaborative, international study.
iTTP in an autoimmune disease caused by autoantibodies directed against the metalloproteinase ADAMTS13. Rituximab is the standard immune suppressive treatment suggested from international guidelines. However, 10-15% of patients do not achieve a sustained ADAMTS13 remission with rituximab, and a significant portion of responders eventually need re-treatment after 12 months or less. Other therapeutic options are scarce and based on old immunosuppressive agents or splenectomy, all burdened by relevant toxicity and lack of solid efficacy data. Recently, targeting CD20-negative long-lived plasma cells appears to be a promising strategy in refractory iTTP. The anti-CD38 monoclonal antibody daratumumab has been employed in selected iTTP patients with good results. However, evidence stems only from isolated case reports. The DarTTP study aims to collect evidence on a larger number of patients about the efficacy and safety of daratumumab in iTTP subjects who are refractory or intolerant to previous immunosuppressive treatments. The primary endpoint is the proportion of patients with ADAMTS13 activity levels above 20% of normal at 6 months from the first daratumumab administration.
Study Type
OBSERVATIONAL
Enrollment
40
Angelo Bianchi Bonomi Hemophilia and Thrombosis Center
Milan, Italy
RECRUITINGProportion of responders to daratumumab
Number of patients responding to daratumumab / total number of patients treated with daratumumab (response defined as the achievement of ADAMTS13 activity levels above 20% of normal at any timepoint from the first daratumumab administration to 12 weeks after the last dose, without new additional immunosuppressants)
Time frame: From the first daratumumab administration to 12 weeks after the last dose
Safety of daratumumab
Number of adverse events related to daratumumab, using CTCAE v5.0
Time frame: From the first daratumumab administration to 24 weeks after
Duration of response
Median ADAMTS13 relapse-free survival after daratumumab treatment
Time frame: From the date of the first documented ADAMTS13 activity >20% after the first dose of daratumumab until the date of ADAMTS13 relapse (i.e., ADAMTS13 activity <20%), assessed up to 3 years.
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