Detailed Data From Gilead Halted Blood Cancer Drug Magrolimab Program Shows Higher Deaths And Side Effects

Magrolimab was the centerpiece of Gilead Sciences Inc's GILD $4.9 billion buyout of Forty Seven Inc in March 2020.

Magrolimab is a monoclonal antibody targeting CD47 for treating various types of blood cancers. But the drug has repeatedly hit speed breakers.

Over the weekend, at the European Hematology Association meeting, Gilead unveiled additional data from the halted trials.

In Phase 3 trial ENHANCE, 539 patients with high-risk myelodysplastic syndromes received either magrolimab and azacitidine (standard treatment) or placebo plus standard treatment.

More magrolimab + azacitidine arm patients discontinued treatment due to adverse events versus the placebo + azacitidine arm.

The number of patients who proceeded to transplant was higher in the placebo + azacitidine arm (35.4%) compared to the magrolimab + azacitidine arm (20.9%).

The study did not meet the primary endpoints of overall survival (median, 15.9 vs. 18.6 months or complete remission rates (CRR) (21.3% vs. 23.6%).

The study showed more severe TEAEs overall, including a higher rate of Grade ≥3 TEAEs.

42.6% of patients in the magrolimab arm experienced anemia compared to 21.2% in the placebo arm.

And 24% of patients in the magrolimab arm discontinued the study compared to 12.1 in the placebo group.

A second phase 3 study, ENHANCE-3, enrolled 378 untreated acute myeloid leukemia patients who weren't eligible for intensive chemotherapy.

In this study, patients received either magrolimab or a placebo on top of azacitidine and Venclexta.

With a median follow-up of 5.4 months, the median overall survival in the magrolimab and placebo arms was 11.7 vs. 10.4 months, respectively.

There were more deaths in the magrolimab arm (n=68, 36.0%) than in the placebo arm (n=58, 30.7%).

In the magrolimab vs. placebo arm, the complete remission (CR) rate within six treatment cycles was 39.7% vs. 42.9%, the median time to CR was 1.08 vs. 1.87 months, and the duration of CR was 7.8 vs. 8.1 months.

A higher incidence of Grade≥ 3 anemia (39.7% vs. 25.0%) and Grade ≥3 infusion-related reactions (3.7% vs. 1.6%) was observed in the magrolimab and placebo arm.

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