Gilead Axes Phase III Magrolimab Trial Based on Disappointing Data

Gilead HQ Silicon Valley

Pictured: Gilead sign and building in Silicon Valley/iStock, Sundry Photography

Gilead Sciences’ anti-CD47 antibody has again disappointed in a Phase III blood cancer trial. The biopharma announced the decision to discontinue another late-stage study of magrolimab Tuesday. 

This is the second Phase III study ended for the investigational treatment. In July 2023, Gilead put a stop to its ENHANCE study of magrolimab for the high-risk myelodysplastic syndromes (MDS).  

Now, the ENHANCE-2 study of the antibody for acute myeloid leukemia (AML) patients with TP53 mutations has also been dropped by Gilead after a mid-trial independent analysis concluded the treatment is “unlikely to demonstrate a survival benefit” compared to standard of care, the company said. 

The therapy targets CD47, a “don't eat me” signal presented by cancer cells to allow them to avoid being targeted by the body’s immune system. By suppressing the signal, patients’ immune cells should be able to attack and destroy the cancer cells.  

Magrolimab was picked up by Gilead in 2020 with a $4.9 billion buy of Forty Seven, an immuno-oncology biotech that spun out of Stanford. Despite promising Phase Ib results in MDS and AML, it has so far been a dud for the company in later stage trials. 

While the anti-CD47 antibody was seen as a potential treatment for blood cancers, so far it has not proven very effective in the clinic. After inking a $2 billion deal in 2020, Chinese biotech I-Mab and partner AbbVie decided to call it quits on a Phase Ib trial of the former’s lemzoparlimab. The antibody was being tested in MDS and AML in combination with azacitidine and venetoclax.  

This week, AbbVie made the decision to cut its losses and terminate its licensing and collaboration agreement with I-Mab for lemzoparlimab. I-Mab’s SEC filing called it a “strategic decision.” AbbVie is out the $200 million upfront it already paid out to I-Mab. 

Celgene, once considered a front runner for the anti-CD47 monoclonal antibody market, terminated its Phase I trial of CC-90002 in 2018 after preliminary data for AML and MDS did “not offer a sufficiently encouraging profile for further dose escalation/expansion.” 

Gilead isn’t throwing in the towel just yet on magrolimab, however. The antibody is still in the ENHANCE-3 study for patients with first-line, unfit AML currently, but the trial is under partial clinical hold to prevent new patients from joining the program. It is also in studies for diffuse large B-cell lymphoma and in solid tumors like triple-negative breast cancer, brain cancer, as well as head and neck squamous cell carcinoma. 

Kate Goodwin is a freelance life science writer based in Des Moines, Iowa. She can be reached at kate.goodwin@biospace.com and on LinkedIn

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