After spending her childhood in Ghana, Greenstreet studied in England and went on to become a physician practicing obstetrics and gynecology in the U.K. Later, she earned an MBA from INSEAD, a top-ranked business school in France. She led drug development divisions at pharma giants GlaxoSmithKline and Pfizer before landing at Alnylam as chief operating officer in 2016.
This year, she got her biggest challenge yet: Succeeding the retiring John Maraganore as CEO of Alnylam, becoming one of just six women and even fewer Black people to have headed a major pharmaceutical company.
Alnylam sells drugs that use a Nobel Prize-winning technique called RNA interference to suppress the expression of selected genes. So far, all of the company’s approved medicines have been designed to treat rare conditions such as hereditary transthyretin-mediated amyloidosis. And all of them come with sky-high price tags — Onpattro, the amyloidosis drug, lists for $450,000 per year.
As Alnylam’s COO and later president, Greenstreet oversaw much of that work. Maraganore told STAT in November that his successor brings “a lot of experience growing and scaling global, complex biopharma companies.” If she can show that Alnylam’s drugs will work against more common conditions — at more affordable prices — then decades-old predictions about the power of RNA interference to treat common diseases could finally start to come true. A drug for high blood pressure called zilebesiran, which completed Phase 1 safety trials in 2021, could be the first to clear this threshold.
In January 2021 Alnylam pledged to become a top-five biotech in market capitalization by 2026. “We believe we are well on our way to achieving these ambitious goals,” Greenstreet says.