The FDA has issued a partial clinical hold on Gilead Sciences' magrolimab trials, specifically those combining the drug with azacitidine. This regulatory action stems from an observed imbalance in investigator-reported serious adverse events across different study arms. The trials impacted include Phase 3 studies targeting myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), along with a Phase 2 trial in myeloid malignancies and a Phase 1b study in MDS.
The partial hold has forced Gilead to pause new patient enrollment in the affected trials while the safety signal is thoroughly investigated. However, current participants already receiving the magrolimab and azacitidine combination will be allowed to continue their treatment. This decision aims to minimize disruption for those who may be benefiting from the therapy while ensuring patient safety remains paramount.
Magrolimab is a CD47-directed antibody designed to block the "don't eat me" signal emitted by cancer cells, enabling macrophages to target and destroy them. CD47 is a protein expressed on malignant cells that prevents the cancer from being attacked by white blood cells called macrophages. The drug represents a significant component of Gilead's oncology strategy, particularly following its acquisition of Forty Seven for $4.9 billion in 2020. In earlier studies, magrolimab combined with azacitidine showed promising results, including a 91% overall response rate (ORR) in previously untreated MDS patients, which led to a breakthrough therapy designation from the FDA.
The trials affected by the partial clinical hold include those evaluating magrolimab in combination with azacitidine for MDS and AML. These include trials for 'unfit' AML patients who are unable to be treated with intensive treatment like high-dose chemotherapy. Other studies of the CD47-directed antibody in large B cell lymphoma, multiple myeloma and solid tumours are not affected as they don't include azacitidine as a study drug.
While Gilead has stated that no clear trend in adverse reactions or new safety signal has been identified at this time, the company is implementing the partial clinical hold across all ongoing magrolimab and azacitidine combination studies worldwide. The outcome of the investigation into the safety signal will be crucial in determining the future development path of magrolimab, a key asset in Gilead's oncology pipeline.
