Phase I/II (MDS)

Opsona has initiated an open label Phase I/II study to assess the safety and efficacy of cycles of intravenously infused doses of Tomaralimab (OPN-305) in patients with second-or third line lower (Low and intermediate-1) risk myelodysplastic syndrome (MDS). The trial commenced as a single centre study in the USA in collaboration with MD Anderson, Houston, Texas, USA. The Phase I part of the study is completed and Phase II is currently ongoing. Three additional USA centres (Montefiore Einstein, Weill Cornell Center and Moffitt Cancer Center) have now been initiated. Further information can be located at

Patients who complete the Phase I/II study and continue to respond have the option to continue to receive treatment under a separate follow up protocol, a number of patients are currently participating in this follow up study.

The initial emerging data was presented at the American Society of Haematology (ASH) in 2016. Further information can be located at

Myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a complex and heterogeneous group of bone marrow failure disorders characterized by ineffective cell maturation (hematopoiesis). This dysfunctional blood cell production is manifested by reduced red blood cell counts, abnormal cell growth and differentiation and cellular dysfunction resulting in an increased risk of infection and need for blood transfusions in most MDS patients.

There is an urgent need for the development of novel therapies, such as Tomaralimab (OPN-305), in the treatment of MDS which can improve patient survival and which have fewer adverse side effects than current standard of care medications.