Gilead’s CD47 woes continue, this time in solid tumours

Just a week after dropping the development of its CD47-targeting antibody magrolimab in blood cancers, Gilead Sciences has paused enrolment in clinical trials of the drug in solid tumours, adding to concerns about the drug’s side effects.

The FDA followed the announcement of the decision yesterday with a request for a partial clinical hold on the trials, which comes after the regulator sought a full clinical hold on all magrolimab studies in acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS).

Gilead abandoned testing of the antibody in AML and MDS after data suggested that patients taking the drug in clinical trials were more likely to die than those in control groups. A futility analysis on the ENHANCE-3 trial in these blood cancers also suggested the drug was unlikely to show efficacy.

The restrictions on enrolling new patients apply to Gilead’s own ELEVATE studies of magrolimab in solid tumours, as well as studies being run by independent investigators.

The ELEVATE programme includes three phase 2 studies involving patients with metastatic triple-negative blood cancer (TNBC), head and neck squamous cell carcinoma (HNSCC), metastatic colorectal cancer (CRC), non-small cell lung cancer (NSCLC), and urothelial carcinoma (UC).

“Gilead is reviewing the benefit-risk of magrolimab across all ongoing trials and will provide an update on this assessment as soon as possible,” said the company in a statement.

“Patients already enrolled in the Gilead-sponsored ELEVATE solid tumour studies and deriving clinical benefit may continue to choose receiving magrolimab following reconsenting to the study with their healthcare provider,” it added.

Magrolimab has been at the forefront of drugs targeting CD47, a protein expressed on cancer cells that sends out a ‘don’t eat me’ signal to macrophage cells of the immune system, and was the main asset in Gilead’s $4.9 billion acquisition of Forty Seven in 2020.

It’s not the first time that CD47-directed drugs have run into problems with either safety or efficacy. Others that have been abandoned as a result include Surface Oncology’s SRF231, which was dropped because of haematological side effects, and Bristol-Myers Squibb’s CC-9002 and follow-up CC-9251, which targeted the SIRPα receptor with which CD47 interacts.

Last year, AbbVie also pulled out of a $1.3 billion R&D partnership with I-Mab on lemzoparlimab for MDS and AML, for undisclosed reasons, although, the drug is still in clinical development in China.

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