Divesiran Delivers a Decisive Phase 2 Win in Polycythemia Vera: 88% Response Rate vs 19% for Placebo

summarizeSummary

Silence Therapeutics announced that its siRNA candidate divesiran met the primary endpoint in the Phase 2 SANRECO trial for polycythemia vera, delivering an 88% response rate versus 19% for placebo. Both dosing schedules proved effective, safety was clean, and a Phase 3 trial is planned for 1H 2027.

check_boxKey Events · Product Development and Regulatory · SLN

• Primary Endpoint Met with 88% Response Rate

  During weeks 18‑36, 88% of divesiran‑treated patients achieved hematocrit control without phlebotomy, compared to 19% on placebo (p<0.0001). The placebo‑adjusted response rate was 69%.

• Both Dose Groups Showed Strong Efficacy

  Response rates reached 93.8% for every‑six‑week dosing and 81.3% for every‑twelve‑week dosing, supporting the convenience of quarterly administration.

• Key Secondary Endpoint Also Met

  Mean phlebotomies per patient were 0.2 for divesiran versus 2.1 for placebo (p<0.0001), demonstrating a dramatic reduction in the need for therapeutic blood draws.

• Clean Safety Profile

  Divesiran was well tolerated with no new safety findings. Injection site reactions were infrequent and self‑limiting; only two grade 1 anemia cases were reported.

auto_awesomeAnalysis · SLN · Life Sciences

A landmark clinical readout for Silence Therapeutics: divesiran achieved a decisive Phase 2 victory in polycythemia vera, with 88% of treated patients meeting the primary endpoint of hematocrit control without phlebotomy, compared to just 19% on placebo. Robust efficacy was observed across both every‑six‑week and every‑twelve‑week dosing schedules, and the drug was well tolerated with no new safety signals. These results position divesiran as a potential best‑in‑class siRNA therapy in a market where Jakafi already generates approximately $1 billion annually despite its limitations. The company plans to initiate a Phase 3 trial in the first half of 2027, following an end‑of‑Phase‑2 meeting by year‑end. This is the most important clinical readout in Silence's history and materially de‑risks the pipeline.