The mid-stage win of Silence Therapeutics’ siRNA drug in polycythemia vera validates the therapeutic approach of similar assets in development—but also sets a high standard for therapies from Takeda, Agios and Disc Medicine.
Silence Therapeutics’ siRNA therapy elicited significantly higher rates of response than placebo in a Phase 2 trial of a rare blood cancer called polycythemia vera—findings that analysts say could give competitors a run for their money.
These findings are “impressive,” William Blair told investors in a Monday note, noting that the readout “reflects a highly competitive profile.” The analysts compared Silence’s asset, dubbed divesiran, to other investigational therapies including Takeda’s rusfertide and Agios’ AG-236. Disc Medicine is similarly playing in the polycythemia vera (PV) arena.
Silence closed Monday’s trading session up 29% at $15.40 per share.
In the Phase 2 SANRECO trial, Silence enrolled 48 patients with PV who are dependent on phlebotomy. Results presented on Monday demonstrated an 88% clinical response rate in the divesiran group, compared to 19% in placebo controls. SANRECO defined treatment response as the absence of phlebotomy and maintaining hematocrit under 45% from weeks 18 through 36.
The treatment benefit—a 69% clinical response advantage in favor of divesiran—is “the best-case scenario for the most important wholly-owned 2026 catalyst” for Silence, H.C. Wainwright told investors in a Monday note. The outcome also “de-risks divesiran,” which is now no longer an uncertain mid-stage bet for the biotech but has grown “into a credible registration asset.”
Silence now plans to push divesiran into late-stage development, testing an every-12-week dosing schedule in a Phase 3 study slated to start in the first half of 2027.
SANRECO’s data has broader implications for the PV space, Truist Securities analysts said on Monday. For Agios, Silence’s readout could have “a de-risking read-through” for AG-236, a siRNA therapeutic that works similarly to divesiran. Agios is moving its asset into Phase 2/3 development in PV, with the Phase 2 portion set to start later this year.
“We see class validation as beneficial to AGIO,” the analysts said.
The same goes for Disc’s DISC-3405, which targets the same pathway as divesiran but is instead a monoclonal antibody. DISC-3405 is in Phase 2 development for PV, with data expected in the third quarter.
In a separate note on Monday, Truist said that SANRECO “validates” the broader approach of this therapeutic class, though the magnitude of divesiran’s benefits “substantially raises the competitive bar” for DISC-3405 and other investigational drugs in PV.
