Exhibit 99.4

Email to Gilead Operating Group

This morning, we announced that Gilead will acquire Forty Seven, a clinical-stage immuno-oncology company, in a $4.9 billion agreement. We’ve included some key messages below and attached an FAQ to help you answer questions you may receive from your teams.

Please do not forward this email — it is meant to help guide conversation.

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Key Talking Points

For Internal Use Only, Not for Distribution

·Gilead is acquiring Forty Seven, Inc. for $4.9 billion. The agreement was unanimously approved by both boards of directors and is expected to close in the second quarter.

·The deal brings magrolimab to Gilead, providing the company with an investigational molecule that has demonstrated promising results in Phase 1b/2 clinical studies for a number of cancers, including myelodysplastic syndrome and acute myeloid leukemia.

·This transaction supports Gilead’s strategic focus in growing its pipeline and expertise in immuno-oncology beyond cell therapy, as we seek to deliver on our ambitious goal of bringing 10 transformative therapies to patients in the next 10 years.

·This is the kind of deal we have said we would pursue — and will continue to pursue — in our efforts to ensure that we have access to the best scientific innovation available, as well as the best talent.

·Forty Seven has a highly experienced team with complementary expertise in a promising area of oncology. We are pleased to be able to add to our expertise in immuno-oncology and look forward to having Forty Seven become part of the Gilead family.