Final data were presented at conference of the Phase II study of rozrolimupab in adult patients with immune thrombocytopenia purpura (ITP).

Rozrolimupab is a fully human recombinant anti-RhD monoclonal antibody (mAb) mixture, currently being investigated in the treatment of ITP.

In this open-label study, 61 patients with RhD positive, non-splenectomised ITP were treated with single infusions of rozrolimupab in doses ranging from 75µg/kg to 300µg/kg. The primary end point was response, defined as platelet counts of >30 x 10^9/L and an increase of >20 x 10^9/L from baseline at day 7.

The trial demonstrated that at 300µg/kg, the optimal dose, eight of 13 (62%) of patients responded at day seven. Median time to response was 59 hours (approximately 2.5 days) and the median duration of response was 14 days.

The most common adverse events, mostly mild or moderate, were headache (18%), pyrexia (13%), chills (8%), and fatigue (8%). Four serious adverse events considered related to study drug were reported: decreased haemoglobin, extravascular haemolysis/dizziness and two cases of transient rise in D-dimer values without clinical symptoms.