On September 15, 2020, the U.S. Food and Drug Administration (FDA) granted breakthrough therapy designation to magrolimab, a first-in-class anti-CD47 monoclonal antibody, to treat newly diagnosed patients with myelodysplastic syndromes (MDS).1
The macrophage immune checkpoint protein CD47 is a ‘do not eat me’ signal that facilitates immune evasion of malignant cells. Therefore, its blockade by magrolimab induces tumor phagocytosis and promotes the elimination of tumor cells. Additionally, CD47 has been reported to be overexpressed in myeloid malignancies, including acute myeloid leukemia (AML) and MDS.2
The FDA decision was based on the promising preliminary results from the phase Ib study of magrolimab in patients with intermediate to very high-risk MDS ineligible for intensive chemotherapy (5F9005, NCT03248479). These results were first presented at the 25th Congress of the European Hematology Association (EHA).
- A total of 30 (91%) from the 33 efficacy evaluable patients achieved an objective response, and after 6 months of follow-up, 91% of them continued in response.
- Moreover, the investigators reported that responses deepened over time, from 42% to 56% of complete responses in patients with ≥ 6 months follow-up.
- Regarding tolerability of the combination, safety was similar to the control arm (azacytidine alone). The most common treatment-related adverse events reported were anemia (44%), fatigue (18%), infusion reaction (18%), neutropenia (8%), and thrombocytopenia (5%). Of note, no patients discontinued due to an adverse event.3
The improved efficacy of the combination of magrolimab with azacytidine in untreated patients with intermediate to very high-risk MDS will be confirmed in the ongoing phase III, double-blind, placebo-controlled, randomized study (ENHANCE, NCT04313881).3
Listen below to the discussion between David Sallman (Moffitt Cancer Center, Tampa, US) and Naval Daver (MD Anderson Cancer Center, Houston, US) about the potential of magrolimab to treat patients with AML and MDS.