Study: Rituximab Originator and Biosimilar Equivalent in iTTP Patients

A recent study published in the British Journal of Haematology looked at immune thrombotic thrombocytopenic purpura (iTTP), an acute multisystem thrombotic microangiopathy mediated by ADAMTS13 autoantibodies. The typical avenue for treatment is with anti-CD20 suppression, which they called a “mainstay” of treatment for this condition. The patent for Mab Thera has expired, they noted, and that has led to the approval of biosimilars for the reference product.

For the current paper, the researchers looked at 84 consecutive patient episodes (over two years), which covered a period prior to and following the patient switches to Truxima. The researchers measured platelet counts, ADAMTS13 activity, and CD19 levels at day one, day 28 and at three months, and also recorded any adverse reactions and infective complications.

According to the results, platelet counts “were not significantly different” between the two treatment groups acutely (day 1, P=0.085; day 28,P= 0.77; 3 months, P=0.71), as well as electively (day 1, P=0.79; day 28, P=0.68; 3 months, P=0.9). The also reported no significant differences in ADAMTS13 recovery either acutely (day 1, P=0.99; day 28, P=0.27; 3 months, P=0.26) or electively (day 1, P=0.59; day 28, P=0.61; 3 months, P=0.34). There were also no significant differences in CD19 depletion at day one and three months acutely or electively. Both therapies were comparable in terms of infusion reactions and infective complications.

“This is the first series of the Rituximab biosimilar Truxima to be reported in iTTP, demonstrating equivalence to MabThera in terms of ADAMTS13 recovery, CD19 depletion, and platelet count at day 28 and three months post‐administration, with comparable infusion and infective complications,” the researchers wrote in their conclusion. “The financial benefit of the biosimilar anti‐CD20 is considerable.”

Read more at the British Journal of Haematology