Agios shares slide 25% as Novo Nordisk sickle cell data rattles rival drug programme

Shares in Agios Pharmaceuticals fell 25 per cent on Monday after Danish pharmaceutical group Novo Nordisk unveiled encouraging clinical data for its experimental sickle cell disease therapy, intensifying competitive pressure on the Boston-based biotech's own late-stage programme in the same indication.

Novo said its drug candidate, etavopivat, delivered a 27 per cent reduction in vaso-occlusive crisis events — the acutely painful episodes that are a defining feature of the inherited blood disorder — and extended the time to first crisis by around four months when added to standard-of-care treatment. The readout sent Agios stock sharply lower, wiping out a quarter of the company's market capitalisation in a single session.

The sell-off underscores how closely investors are tracking the competitive dynamics in sickle cell disease, where a cluster of drug developers is pursuing therapies that target pyruvate kinase, an enzyme involved in red blood cell metabolism. Agios has been working with the US Food and Drug Administration to identify a viable path forward for its own PK activator, mitapivat, after the drug failed a pivotal phase 3 trial in the disease, in the hope of securing an accelerated approval.

Gregory Renza, analyst at Truist, which maintains a buy rating on the stock, said the Novo readout "creates separation amongst PK class candidates" but argued that much of the bad news was already priced in. He added that the firm continued to see "a place for mitapivat in SCD given the high unmet need globally", pointing to Agios's expanding infrastructure and reputation within the haematological disease community.

Other analysts struck a more cautious note. James Condulis at Stifel said Novo's drug "met its primary endpoints, which is surprising after AGIO's setback", flagging the result as "arguably most negative" for Agios, given the two drugs share a mechanism of action and the US group's programme had previously stumbled in phase 3.

Sickle cell disease, which affects millions of patients globally and is concentrated in populations of African descent, has long been flagged as an area of substantial unmet medical need. A string of recent therapeutic advances — including the arrival of gene therapies — has drawn fresh commercial attention from global pharmaceutical groups. Novo Nordisk, better known for its dominance in diabetes and obesity, has been expanding its rare disease footprint, and a successful etavopivat programme would give the Danish group a foothold in a therapy area where differentiated mechanisms remain scarce.

Agios shares, already under pressure from the earlier phase 3 disappointment, have now given up a significant portion of the gains they had accumulated on hopes that a regulatory workaround could salvage the mitapivat programme.