Symphogen meets Phase II endpoints
Danish Symphogen has published positive study results with the first recombinant polyclonal antibody therapy ever tested in clinical trials.
Results of an open-label, dose-escalation Phase II study including 61 patients with primary immune thromocytopenia (ITP) suggest that a single injection of rozrolimupab (SYM001) is safe and boosts platelet counts significantly (Blood). In doses ranging from 75-300µg/kg the recombinantly produced mixture of 25 fully human anti-Rhesus D (RhD)-specific antibodies induced mild adverse effects in up to 20% of the volunteers, mostly headache (20%) and pyrexia (13%). In 8 out of 13 patients (62%), Symphogen’s lead drug induced an increase in platelet counts of at least 20x109/L after 72 hours that persisted for seven days after injection. Median time to response was 59 hours and the median duration of response was 14 days.
Lead investigator Professor Tadeusz Robak, from Lodz University said: “These phase II results suggest an efficacy and safety profile similar to that seen with plasma derived immunoglobulin products. Rozrolimupab can be produced indefinitely and may represent a novel and convenient replacement for blood-derived immunoglobulins with more limited supply.” Kirsten Drejer, Symphogen chief executive officer, added: “The multicenter study included involvement of the regulatory authorities of the USA, Europe and Asia, and we are confident that antibody mixtures represent a viable new class of antibody therapeutics offering well-characterized and potentially more efficacious alternatives to existing treatments.”
Symphogen’s rozrolimupab is the first human recombinant mixture of 25 antibodies which has been clinically tested. The mixture is manufactured simultaneously from a single batch, mimicking the natural diversity of the human antibody response. Sym001 is being developed as an alternative to existing anti-RhD hyperimmune immunoglobulins for the treatment of Idiopathic Thrombocytopenic Purpura (ITP) and the prevention of Hemolytic Disease of Newborns (HDN). Sym001 is being co-developed with Swedish Biovitrum AB. Idiopathic Thrombocytopenic Purpura is an autoimmune bleeding disorder caused by abnormally low platelet levels, making it difficult for the blood to clot normally. Hemolytic Disease in Newborns is a Rhesus D-negative woman becoming sensitive to RhD during the pregnancy with or delivery of a Rhesus D-positive child. This immune reaction may trigger a maternal antibody response in subsequent RhD-positive pregnancies, causing the breakdown of fetal red blood cells.