Dive Brief:

• The Food and Drug Administration has cleared Gilead to restart some trials testing an experimental cancer drug the company acquired in a roughly $5 billion buyout two years ago, following an investigation into safety concerns that arose in January.

• The FDA had suspended a majority of the clinical trials of the drug, known as magrolimab, after investigators observed an “imbalance” in suspected, unexpected serious adverse reactions in blood cancer patients treated with the medicine and the chemotherapy azacitidine. But after reviewing safety data from each study, the agency has allowed Gilead to restart them.

• Gilead will resume enrollment in three Phase 3 studies in certain blood cancers, among them tests in front-line acute myeloid leukemia and myelodysplastic syndrome, as well as two other earlier-stage trials. Other studies in lymphoma and multiple myeloma remain on hold, however.

Dive Insight:

Gilead’s long-running plan to build an oncology business has hit a few roadblocks recently, and magrolimab’s uncertain prospects are a big reason why.

The drug was acquired through a buyout of Forty Seven, one of a number transactions done by the company over the past two years to bulk up its cancer drug pipeline. The spending spree, which also includes a buyout of Immunomedics as well as a wide-ranging alliance with Arcus Biosciences, cost Gilead $27 billion. Yet, Gilead has so far little to show for its dealmaking.

While Gilead’s $21 billion deal for Immunomedics yielded an approved drug, Trodelvy, the company’s recent disclosure from a clinical trial in breast cancer raised doubts about its possible impact. The Arcus alliance has not yet paid dividends. Magrolimab, meanwhile, was set back and delayed even before the FDA suspended testing. The partial clinical hold the agency placed on trials added to questions about the Forty Seven deal, analysts said at the time.

Gilead’s shares have fallen 15% this year — in line with the year-to-date decline in the IBB, a biotech stock index fund, but in contrast to market gains for some of Gilead’s peers like Amgen, Vertex and Regeneron.

A green light from the FDA to restart testing, then, is “a much-needed piece of good news” for Gilead, wrote Brian Abrahams, an analyst at RBC Capital Markets, in a note to clients. Though trials in lymphoma and multiple myeloma remain on hold, Gilead can resume all of the drug’s late-stage studies, among them a Phase 3 trial in myelodysplastic syndrome that could be its quickest path to market.

Gilead said it already enrolled enough patients in that study, known as ENHANCE, to get to an interim analysis, so it “remains on schedule” to deliver results in 2023. The Phase 3 trial in AML, meanwhile, could read out in September of next year, according to a federal clinical trials database.

Questions still hang over the program, though. Gilead hasn’t said what specific safety concerns led the FDA to stop testing. Some analysts suggested the issue may be anemia triggered by an abnormal reduction in blood-clotting platelets.

Speculation will continue, at least for now, as Gilead didn’t provide any additional details in its announcement. Abrahams, though, noted the “relatively quick removal” of the clinical hold suggests there “was likely no clearly discernible adverse event pattern.”

“We see a higher likelihood of [magrolimab] ultimately getting over the line,” he wrote.

Magrolimab is part of an emerging class of drugs, known as CD47 inhibitors, viewed by Gilead and others as the potential backbone for new immunotherapy combinations. More than a dozen are in clinical trials, and Gilead’s drug is among the most advanced of the group.